Regenerative Endodontic Treatment of an Immature Necrotic Molar with Arrested Root Development by Using Recombinant Human Platelet-derived Growth Factor: A Case Report.

PubMed

Zhujiang, Annie; Kim, Sahng G

2016-01-01

Regenerative endodontic treatment has provided a treatment option that aims to allow root maturation. The present report describes the regenerative endodontic treatment of a necrotic, immature molar by using recombinant human platelet-derived growth factor (rhPDGF-BB) and shows the continued root maturation in the tooth with arrested root development. A regenerative endodontic procedure that used a growth factor was performed for a necrotic molar with arrested root formation in a 20-year-old patient. Thorough disinfection by using mechanical instrumentation and copious irrigation of antimicrobial agents as well as intracanal medication with calcium hydroxide was performed throughout the first 2 appointments. At the third appointment, the root canals were irrigated with an antimicrobial solution and 17% EDTA, and bleeding was evoked by passing sterile paper points beyond the apex in each canal. Small pieces of a collagen membrane saturated with rhPDGF-BB solution from GEM 21S were packed into each canal. Mineral trioxide aggregate was placed, and Cavit and composite resin were used to restore the tooth. Complete root maturation and resolution of a periapical radiolucency were observed at the 15-month follow-up. The present report presents a regenerative endodontic procedure that uses rhPDGF-BB for a necrotic molar with arrested root development. The finding of continued root development in the present case suggests that regenerative endodontic treatment may be able to resume the root maturation process in teeth with arrested root formation. Further clinical studies are required to investigate the efficacy of rhPDGF-BB in regenerative endodontic treatment. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Influence of light and shoot development stage on leaf photosynthesis and carbohydrate status during the adventitious root formation in cuttings of Corylus avellana L.

PubMed Central

Tombesi, Sergio; Palliotti, Alberto; Poni, Stefano; Farinelli, Daniela

2015-01-01

Adventitious root formation in plant cuttings is influenced by many endogenous and environmental factors. Leaf photosynthesis during rooting of leafy cuttings in hard to root species can contribute to supply carbohydrates to the intensive metabolic processes related to adventious root formation. Light intensity during rooting is artificially kept low to decrease potential cutting desiccation, but can be limiting for photosynthetic activity. Furthermore, leafy cuttings collected from different part of the shoot can have a different ability to fuel adventitious root formation in cutting stem. The aim of this work was to determine the role of leaf photosynthesis on adventitious root formation in hazelnut (Corylus avellana L) (a hard-to-root specie) leafy cuttings and to investigate the possible influence of the shoot developmental stage on cutting rooting and survival in the post-rooting phase. Cutting rooting was closely related to carbohydrate content in cutting stems during the rooting process. Cutting carbohydrate status was positively influenced by leaf photosynthesis during rooting. Non-saturating light exposure of leafy cuttings can contribute to improve photosynthetic activity of leafy cuttings. Collection of cuttings from different part of the mother shoots influenced rooting percentage and this appear related to the different capability to concentrate soluble sugars in the cutting stem during rooting. Adventitious root formation depend on the carbohydrate accumulation at the base of the cutting. Mother shoot developmental stage and leaf photosynthesis appear pivotal factors for adventitious roots formation. PMID:26635821

Evaluating success of autotransplantation of embedded/impacted third molars harvested using piezosurgery: a pilot study.

PubMed

Nagori, Shakil Ahmed; Jose, Anson; Bhutia, Ongkila; Roychoudhury, Ajoy

2014-11-01

To evaluate the success of autogenous transplantation of embedded/impacted third molars harvested using piezosurgery. This prospective pilot study enrolled 20 healthy patients with non-restorable first/second molars and a caries-free retrievable embedded/impacted third molar. Piezosurgery was used for removing inter-radicular bone at the recipient socket as well as for bone removal around the donor teeth. After an average follow-up of 16.4 months (SD = 1.9), 18 cases were successful with formation of periodontal ligament around the teeth. One tooth was lost due to infection at 1 month. One patient was lost to follow-up. There was no root resorption or ankylosis in any of the cases. In six donor teeth with complete root formation, root canal treatment was carried out. All the remaining teeth responded positively with vitality testing. Piezosurgery is an effective device if embedded/impacted third molars are to be harvested for successful autogenous transplantation.

Remodeling of the Infection Chamber before Infection Thread Formation Reveals a Two-Step Mechanism for Rhizobial Entry into the Host Legume Root Hair1

PubMed Central

Teillet, Alice; Chabaud, Mireille; Ivanov, Sergey; Genre, Andrea; Limpens, Erik; de Carvalho-Niebel, Fernanda; Barker, David G.

2015-01-01

In many legumes, root entry of symbiotic nitrogen-fixing rhizobia occurs via host-constructed tubular tip-growing structures known as infection threads (ITs). Here, we have used a confocal microscopy live-tissue imaging approach to investigate early stages of IT formation in Medicago truncatula root hairs (RHs) expressing fluorescent protein fusion reporters. This has revealed that ITs only initiate 10 to 20 h after the completion of RH curling, by which time major modifications have occurred within the so-called infection chamber, the site of bacterial entrapment. These include the accumulation of exocytosis (M. truncatula Vesicle-Associated Membrane Protein721e)- and cell wall (M. truncatula EARLY NODULIN11)-associated markers, concomitant with radial expansion of the chamber. Significantly, the infection-defective M. truncatula nodule inception-1 mutant is unable to create a functional infection chamber. This underlines the importance of the NIN-dependent phase of host cell wall remodeling that accompanies bacterial proliferation and precedes IT formation, and leads us to propose a two-step model for rhizobial infection initiation in legume RHs. PMID:25659382

Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

NASA Technical Reports Server (NTRS)

Ng, Y. K.; Moore, R.

1985-01-01

The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

Autotransplantation of mandibular third molar: a case report.

PubMed

Ravi Kumar, Pabbati; Jyothi, Mandava; Sirisha, Kantheti; Racca, Khushboo; Uma, Chalasani

2012-01-01

Autogenous transplantation is a feasible, fast, and economical option for the treatment of nonsalvageable teeth when a suitable donor tooth is available. This paper presents successful autotransplantation of a mature mandibular left third molar (38) without anatomical variances is used to replace a mandibular left second molar (37). The mandibular second molar was nonrestorable due to extensive root caries and resorption of distal root. After extraction of mandibular second and third molars, root canal therapy was done for the third molar extraorally, and the tooth was reimplanted into the extracted socket of second molar site. After one year, clinical and radiographic examination revealed satisfactory outcome with no signs or symptoms suggestive of pathology. In selected cases, autogenous tooth transplantation, even after complete root formation of the donor tooth, may be considered as a practical treatment alternative to conventional prosthetic rehabilitation or implant treatment.

Reactive oxygen species and nitric oxide are involved in polyamine-induced growth inhibition in wheat plants.

PubMed

Recalde, Laura; Vázquez, Analía; Groppa, María D; Benavides, María Patricia

2018-03-06

Polyamines (PAs) produce H 2 O 2 and nitric oxide (NO) during their normal catabolism and modulate plant growth and development. To explore the biochemical basis of PAs-induced growth inhibition in Triticum aestivum L seedlings, we examined the role of O 2 ·- , H 2 O 2 or NO in shoot and root development. Although all PA treatments resulted in a variable reduction of root and shoot elongation, spermine (Spm) caused the greater inhibition in a similar way to that observed with the NO donor, sodium nitroprusside (SNP). In both cases, O 2 ·- production was completely blocked whereas H 2 O 2 formation was high in the root apex under SNP or Spm treatments. Catalase recovered root and shoot growth in SNP but not in Spm-treated plants, revealing the involvement of H 2 O 2 in SNP-root length reduction. The addition of the NO scavenger, cPTIO, restored root length in SNP- or Spm-treated plants, respectively, and partially recovered O 2 ·- levels, compared to the plants exposed to PAs or SNP without cPTIO. A strong correlation was observed between root growth restoration and O 2 ·- accumulation after treating roots with SNP + aminoguanidine, a diamine oxidase inhibitor, and with SNP + 1,8-diaminoctane, a polyamine oxidase inhibitor, confirming the essential role of O 2 ·- formation for root growth and the importance of the origin and level of H 2 O 2 . The differential modulation of wheat growth by PAs through reactive oxygen species or NO is discussed. Graphical abstract Polyamines, nitric oxide and ROS interaction in plants during plant growth.

Histologic Outcomes of Uninfected Human Immature Teeth Treated with Regenerative Endodontics: 2 Case Reports.

PubMed

Nosrat, Ali; Kolahdouzan, Alireza; Hosseini, Farzaneh; Mehrizi, Ehsan A; Verma, Prashant; Torabinejad, Mahmoud

2015-10-01

A growing body of evidence exists showing the possibility of growing vital tissues in the root canal spaces of teeth with necrotic pulps and open apices. However, there is very limited histologic information regarding characteristics of tissues formed in the root canal space of human teeth after regenerative endodontics. The aim of this study was to examine clinically and histologically the outcomes of human immature teeth treated with regenerative endodontics. Two healthy birooted human maxillary first premolar teeth scheduled for extraction were included. Preoperative radiographs confirmed that these teeth had immature apices. Vitality tests showed the presence of vital pulps in these teeth. After receiving consent forms, the teeth were isolated with a rubber dam, and the pulps were completely removed. After the formation of blood clots in the canals, the teeth were covered with mineral trioxide aggregate. Four months later, the teeth were clinically and radiographically evaluated, extracted, and examined histologically. Both patients remained asymptomatic after treatment. Radiographic examination of the teeth showed signs of root development after treatment. Histologic examination of tissues growing into the root canal space of these teeth shows the presence of connective tissue, bone and cementum formation, and thickening of roots. Based on our findings, it appears that when canals of teeth with open apices are treated with regenerative endodontics, tissues of the periodontium grow into the root canals of these teeth. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effects of phosphorus supply on growth, phosphate concentration and cluster-root formation in three Lupinus species

PubMed Central

Abdolzadeh, Ahmad; Wang, Xing; Veneklaas, Erik J.; Lambers, Hans

2010-01-01

Background and Aims In some lupin species, phosphate deficiency induces cluster-root formation, which enhances P uptake by increasing root surface area and, more importantly, the release of root exudates which enhances P availability. Methods Three species of Lupinus, L. albus, L. atlanticus and L. micranthus, with inherently different relative growth rates were cultivated under hydroponics in a greenhouse at four phosphate concentrations (1, 10, 50 and 150 µm) to compare the role of internal P in regulating cluster-root formation. Key Results The highest growth rate was observed in L. atlanticus, followed by L. albus and L. micranthus. At 1 µm P, cluster-root formation was markedly induced in all three species. The highest P uptake and accumulation was observed in L. micranthus, followed by L. atlanticus and then L. albus. Inhibition of cluster-root formation was severe at 10 µm P in L. atlanticus, but occurred stepwise with increasing P concentration in the root medium in L. albus. Conclusions In L. atlanticus and L. albus cluster-root formation was suppressed by P treatments above 10 µm, indicating a P-inducible regulating system for cluster-root formation, as expected. By contrast, production of cluster roots in L. micranthus, in spite of a high internal P concentration, indicated a lower sensitivity to P status, which allowed P-toxicity symptoms to develop. PMID:20037142

Metabolic analysis of the increased adventitious rooting mutant of Artemisia annua reveals a role for the plant monoterpene borneol in adventitious root formation.

PubMed

Tian, Na; Liu, Shuoqian; Li, Juan; Xu, Wenwen; Yuan, Lin; Huang, Jianan; Liu, Zhonghua

2014-08-01

Adventitious root (AR) formation is a critical process for plant clonal propagation. The role of plant secondary metabolites in AR formation is still poorly understood. Chemical and physical mutagenesis in combination with somatic variation were performed on Artemisia annua in order to obtain a mutant with changes in adventitious rooting and composition of plant secondary metabolites. Metabolic and morphological analyses of the iar (increased adventitious rooting) mutant coupled with in vitro assays were used to elucidate the relationship between plant secondary metabolites and AR formation. The only detected differences between the iar mutant and wild-type were rooting capacity and borneol/camphor content. Consistent with this, treatment with borneol in vitro promoted adventitious rooting in wild-type. The enhanced rooting did not continue upon removal of borneol. The iar mutant displayed no significant differences in AR formation upon treatment with camphor. Together, our results suggest that borneol promotes adventitious rooting whereas camphor has no effect on AR formation. © 2013 Scandinavian Plant Physiology Society.

Origin, timing, and gene expression profile of adventitious rooting in Arabidopsis hypocotyls and stems.

PubMed

Welander, Margareta; Geier, Thomas; Smolka, Anders; Ahlman, Annelie; Fan, Jing; Zhu, Li-Hua

2014-02-01

Adventitious root (AR) formation is indispensable for vegetative propagation, but difficult to achieve in many crops. Understanding its molecular mechanisms is thus important for such species. Here we aimed at developing a rooting protocol for direct AR formation in stems, locating cellular AR origins in stems and exploring molecular differences underlying adventitious rooting in hypocotyls and stems. In-vitro-grown hypocotyls or stems of wild-type and transgenic ecotype Columbia (Col-0) of Arabidopsis thaliana were rooted on rooting media. Anatomy of AR formation, qRT-PCR of some rooting-related genes and in situ GUS expression were carried out during rooting from hypocotyls and stems. We developed a rooting protocol for AR formation in stems and traced back root origins in stems by anatomical and in situ expression studies. Unlike rooting in hypocotyls, rooting in stems was slower, and AR origins were mainly from lateral parenchyma of vascular bundles and neighboring starch sheath cells as well as, to a lesser extent, from phloem cap and xylem parenchyma. Transcript levels of GH3-3, LBD16, LBD29, and LRP1 in hypocotyls and stems were similar, but transcript accumulation was delayed in stems. In situ expression signals of DR5::GUS, LBD16::GUS, LBD29::GUS, and rolB::GUS reporters in stems mainly occurred at the root initiation sites, suggesting their involvement in AR formation. We have developed an efficient rooting protocol using half-strength Lepoivre medium for studying AR formation in stems, traced back the cellular AR origins in stems, and correlated expression of rooting-related genes with root initiation sites.

Effect of exogenous hydrogen peroxide on biophoton emission from radish root cells.

PubMed

Rastogi, Anshu; Pospísil, Pavel

2010-01-01

Biophotons spontaneously emitted from radish root cells were detected using highly sensitive photomultiplier tube. Freshly isolated radish root cells exhibited spontaneous photon emission of about 4 counts s(-1). Addition of hydrogen peroxide to the cells caused significant enhancement in biophoton emission to about 500 counts s(-1). Removal of molecular oxygen using glucose/glucose oxidase system and scavengering of reactive oxygen species by reducing agents such are sodium ascorbate and cysteine completely diminished biophoton emission. Spectral analysis of the hydrogen peroxide-induced biophoton emission indicates that biophotons are emitted mainly in green-red region of the spectra. The data provided by electron paramagnetic resonance spin-trapping technique showed that formation of singlet oxygen observed after addition of H2O2 correlates with enhancement in biophoton emission. These observations provide direct evidence that singlet oxygen is involved in biophoton emission from radish root cells. Copyright 2010 Elsevier Masson SAS. All rights reserved.

[A method for rapid extracting three-dimensional root model of vivo tooth from cone beam computed tomography data based on the anatomical characteristics of periodontal ligament].

PubMed

Zhao, Y J; Wang, S W; Liu, Y; Wang, Y

2017-02-18

To explore a new method for rapid extracting and rebuilding three-dimensional (3D) digital root model of vivo tooth from cone beam computed tomography (CBCT) data based on the anatomical characteristics of periodontal ligament, and to evaluate the extraction accuracy of the method. In the study, 15 extracted teeth (11 with single root, 4 with double roots) were collected from oral clinic and 3D digital root models of each tooth were obtained by 3D dental scanner with a high accuracy 0.02 mm in STL format. CBCT data for each patient were acquired before tooth extraction, DICOM data with a voxel size 0.3 mm were input to Mimics 18.0 software. Segmentation, Morphology operations, Boolean operations and Smart expanded function in Mimics software were used to edit teeth, bone and periodontal ligament threshold mask, and root threshold mask were automatically acquired after a series of mask operations. 3D digital root models were extracted in STL format finally. 3D morphology deviation between the extracted root models and corresponding vivo root models were compared in Geomagic Studio 2012 software. The 3D size errors in long axis, bucco-lingual direction and mesio-distal direction were also calculated. The average value of the 3D morphology deviation for 15 roots by calculating Root Mean Square (RMS) value was 0.22 mm, the average size errors in the mesio-distal direction, the bucco-lingual direction and the long axis were 0.46 mm, 0.36 mm and -0.68 mm separately. The average time of this new method for extracting single root was about 2-3 min. It could meet the accuracy requirement of the root 3D reconstruction fororal clinical use. This study established a new method for rapid extracting 3D root model of vivo tooth from CBCT data. It could simplify the traditional manual operation and improve the efficiency and automation of single root extraction. The strategy of this method for complete dentition extraction needs further research.

Plasma membrane H(+)-ATPase is involved in methyl jasmonate-induced root hair formation in lettuce (Lactuca sativa L.) seedlings.

PubMed

Zhu, Changhua; Yang, Na; Ma, Xiaoling; Li, Guijun; Qian, Meng; Ng, Denny; Xia, Kai; Gan, Lijun

2015-06-01

Our results show that methyl jasmonate induces plasma membrane H (+) -ATPase activity and subsequently influences the apoplastic pH of trichoblasts to maintain a cell wall pH environment appropriate for root hair development. Root hairs, which arise from root epidermal cells, are tubular structures that increase the efficiency of water absorption and nutrient uptake. Plant hormones are critical regulators of root hair development. In this study, we investigated the regulatory role of the plasma membrane (PM) H(+)-ATPase in methyl jasmonate (MeJA)-induced root hair formation. We found that MeJA had a pronounced effect on the promotion of root hair formation in lettuce seedlings, but that this effect was blocked by the PM H(+)-ATPase inhibitor vanadate. Furthermore, MeJA treatment increased PM H(+)-ATPase activity in parallel with H(+) efflux from the root tips of lettuce seedlings and rhizosphere acidification. Our results also showed that MeJA-induced root hair formation was accompanied by hydrogen peroxide accumulation. The apoplastic acidification acted in concert with reactive oxygen species to modulate root hair formation. Our results suggest that the effect of MeJA on root hair formation is mediated by modulation of PM H(+)-ATPase activity.

Strigolactones Suppress Adventitious Rooting in Arabidopsis and Pea1[C][W][OA

PubMed Central

Rasmussen, Amanda; Mason, Michael Glenn; De Cuyper, Carolien; Brewer, Philip B.; Herold, Silvia; Agusti, Javier; Geelen, Danny; Greb, Thomas; Goormachtig, Sofie; Beeckman, Tom; Beveridge, Christine Anne

2012-01-01

Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation. PMID:22323776

Strigolactones suppress adventitious rooting in Arabidopsis and pea.

PubMed

Rasmussen, Amanda; Mason, Michael Glenn; De Cuyper, Carolien; Brewer, Philip B; Herold, Silvia; Agusti, Javier; Geelen, Danny; Greb, Thomas; Goormachtig, Sofie; Beeckman, Tom; Beveridge, Christine Anne

2012-04-01

Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative divisions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation.

Root Formation in Ethylene-Insensitive Plants1

PubMed Central

Clark, David G.; Gubrium, Erika K.; Barrett, James E.; Nell, Terril A.; Klee, Harry J.

1999-01-01

Experiments with ethylene-insensitive tomato (Lycopersicon esculentum) and petunia (Petunia × hybrida) plants were conducted to determine if normal or adventitious root formation is affected by ethylene insensitivity. Ethylene-insensitive Never ripe (NR) tomato plants produced more belowground root mass but fewer aboveground adventitious roots than wild-type Pearson plants. Applied auxin (indole-3-butyric acid) increased adventitious root formation on vegetative stem cuttings of wild-type plants but had little or no effect on rooting of NR plants. Reduced adventitious root formation was also observed in ethylene-insensitive transgenic petunia plants. Applied 1-aminocyclopropane-1-carboxylic acid increased adventitious root formation on vegetative stem cuttings from NR and wild-type plants, but NR cuttings produced fewer adventitious roots than wild-type cuttings. These data suggest that the promotive effect of auxin on adventitious rooting is influenced by ethylene responsiveness. Seedling root growth of tomato in response to mechanical impedance was also influenced by ethylene sensitivity. Ninety-six percent of wild-type seedlings germinated and grown on sand for 7 d grew normal roots into the medium, whereas 47% of NR seedlings displayed elongated taproots, shortened hypocotyls, and did not penetrate the medium. These data indicate that ethylene has a critical role in various responses of roots to environmental stimuli. PMID:10482660

Comparison of in vivo dental pulp responses to capping with iRoot BP Plus and mineral trioxide aggregate.

PubMed

Shi, S; Bao, Z F; Liu, Y; Zhang, D D; Chen, X; Jiang, L M; Zhong, M

2016-02-01

To compare dental pulp responses to capping with iRoot BP Plus and mineral trioxide aggregate (MTA) in dogs. Pulps in 36 incisors of three 8-month-old beagle dogs were mechanically exposed and assigned to two experimental groups (iRoot BP Plus group and MTA group, n = 15 per group) and one control group (n = 6). Direct pulp capping was performed using either iRoot BP Plus or MTA. The animals were sacrificed 3 months later. Histological sections were stained with haematoxylin and eosin and categorized using a histologic scoring system. Statistical analysis was performed using the Mann-Whitney U-test, with the significance set at 0.05. The majority of specimens in both experimental groups were associated with complete calcified bridge formation and the absence of pulpal inflammation. There was no significant difference in pulp response to iRoot BP Plus or MTA after 3 months (P > 0.05). iRoot BP Plus and MTA had similar favourable results when used as pulp-capping agents. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Regulation of root hair initiation and expansin gene expression in Arabidopsis

NASA Technical Reports Server (NTRS)

Cho, Hyung-Taeg; Cosgrove, Daniel J.

2002-01-01

The expression of two Arabidopsis expansin genes (AtEXP7 and AtEXP18) is tightly linked to root hair initiation; thus, the regulation of these genes was studied to elucidate how developmental, hormonal, and environmental factors orchestrate root hair formation. Exogenous ethylene and auxin, as well as separation of the root from the medium, stimulated root hair formation and the expression of these expansin genes. The effects of exogenous auxin and root separation on root hair formation required the ethylene signaling pathway. By contrast, blocking the endogenous ethylene pathway, either by genetic mutations or by a chemical inhibitor, did not affect normal root hair formation and expansin gene expression. These results indicate that the normal developmental pathway for root hair formation (i.e., not induced by external stimuli) is independent of the ethylene pathway. Promoter analyses of the expansin genes show that the same promoter elements that determine cell specificity also determine inducibility by ethylene, auxin, and root separation. Our study suggests that two distinctive signaling pathways, one developmental and the other environmental/hormonal, converge to modulate the initiation of the root hair and the expression of its specific expansin gene set.

Root-derived auxin contributes to the phosphorus-deficiency-induced cluster-root formation in white lupin (Lupinus albus).

PubMed

Meng, Zhi Bin; You, Xue Di; Suo, Dong; Chen, Yun Long; Tang, Caixian; Yang, Jian Li; Zheng, Shao Jian

2013-08-01

Formation of cluster roots is a typical morphological response to phosphorus (P) deficiency in white lupin (Lupinus albus), but its physiological and molecular mechanisms are still unclear. We investigated the role of auxin in the initiation of cluster roots by distinguishing the sources of auxin, measuring the longitudinal distribution patterns of free indole-3-acetic acid (IAA) along the root and the related gene expressions responsible for polar auxin transport (PAT) in different developmental stages of cluster roots. We found that removal of shoot apex or primary root apex and application of auxin-influx or -efflux transport inhibitors, 3-chloro-4-hydroxyphenylacetic acid, N-1-naphthylphthalamic acid and 2,3,5-triiodobenzoic acid, to the stem did not affect the number of cluster roots and the free-IAA concentration in the roots of P-deficient plants, but when these inhibitors were applied directly to the growth media, the cluster-root formation was greatly suppressed, suggesting the fundamental role of root-derived IAA in cluster-root formation. The concentration of free IAA in the roots was higher in P-deficient plants than in P-adequate ones, and the highest in the lateral-root apex and the lowest in the mature cluster roots. Meanwhile the expression patterns of LaAUX1, LaPIN1 and LaPIN3 transcripts related to PAT was consistent with concentrations of free IAA along the lateral root, indicating the contribution of IAA redistribution in the cluster-root development. We proposed that root-derived IAA plays a direct and important role in the P-deficiency-induced formation of cluster roots. Copyright © Physiologia Plantarum 2012.

Endodontic Treatment of an Autogenous Transplanted Tooth Using an Er,Cr:YSGG Laser and Radial Firing Tips: Case Report.

PubMed

Martins, Miguel Rodrigues; Lima, Rita C; Pina-Vaz, Irene; Carvalho, Manuel Fontes; Gutknecht, Norbert

2016-10-01

Although several surgical techniques have been reported, no study has yet reported alternative strategies for endodontic treatment of autogenous transplanted teeth. Therefore, the aim of this clinical report is to present the long-term endodontic outcome of a nonvital autogenously transplanted third molar treated with an Er,Cr:YSGG laser and radial firing tips (RFTs). Autogenous tooth transplantation can be considered an alternative to restore edentulous areas and, in donor's teeth with complete root formation, root canal treatment should be performed up to 14 days following transplantation. In the present case report, the patient returned only after 6 months, with clinical and radiological signs of apical periodontitis (AP) associated with the transplanted tooth. Instead of traditional endodontic chemical irrigants or medications, the protocol for smear-layer removal and root canal disinfection was based on intracanal irradiation with an Er,Cr:YSGG laser and RFTs. After 3-years' follow-up, the complete reestablishment of the periodontal ligament and the arrest of the resorptive process could be noticed. This protocol has shown to be effective for the endodontic treatment of a transplanted multi-rooted tooth with AP. Further randomized clinical trials should be conducted to clearly demonstrate the effectiveness of this laser-assisted endodontic protocol.

Regulation of Hormonal Control, Cell Reprogramming, and Patterning during De Novo Root Organogenesis1[OPEN

PubMed Central

Bustillo-Avendaño, Estefano; Ibáñez, Sergio; Sanz, Oscar; Sousa Barros, Jessica Aline; Gude, Inmaculada; Perianez-Rodriguez, Juan; Micol, José Luis; Del Pozo, Juan Carlos

2018-01-01

Body regeneration through formation of new organs is a major question in developmental biology. We investigated de novo root formation using whole leaves of Arabidopsis (Arabidopsis thaliana). Our results show that local cytokinin biosynthesis and auxin biosynthesis in the leaf blade followed by auxin long-distance transport to the petiole leads to proliferation of J0121-marked xylem-associated tissues and others through signaling of INDOLE-3-ACETIC ACID INDUCIBLE28 (IAA28), CRANE (IAA18), WOODEN LEG, and ARABIDOPSIS RESPONSE REGULATORS1 (ARR1), ARR10, and ARR12. Vasculature proliferation also involves the cell cycle regulator KIP-RELATED PROTEIN2 and ABERRANT LATERAL ROOT FORMATION4, resulting in a mass of cells with rooting competence that resembles callus formation. Endogenous callus formation precedes specification of postembryonic root founder cells, from which roots are initiated through the activity of SHORT-ROOT, PLETHORA1 (PLT1), and PLT2. Primordia initiation is blocked in shr plt1 plt2 mutant. Stem cell regulators SCHIZORIZA, JACKDAW, BLUEJAY, and SCARECROW also participate in root initiation and are required to pattern the new organ, as mutants show disorganized and reduced number of layers and tissue initials resulting in reduced rooting. Our work provides an organ regeneration model through de novo root formation, stating key stages and the primary pathways involved. PMID:29233938

Regulation of Hormonal Control, Cell Reprogramming, and Patterning during De Novo Root Organogenesis.

PubMed

Bustillo-Avendaño, Estefano; Ibáñez, Sergio; Sanz, Oscar; Sousa Barros, Jessica Aline; Gude, Inmaculada; Perianez-Rodriguez, Juan; Micol, José Luis; Del Pozo, Juan Carlos; Moreno-Risueno, Miguel Angel; Pérez-Pérez, José Manuel

2018-02-01

Body regeneration through formation of new organs is a major question in developmental biology. We investigated de novo root formation using whole leaves of Arabidopsis ( Arabidopsis thaliana ). Our results show that local cytokinin biosynthesis and auxin biosynthesis in the leaf blade followed by auxin long-distance transport to the petiole leads to proliferation of J0121-marked xylem-associated tissues and others through signaling of INDOLE-3-ACETIC ACID INDUCIBLE28 (IAA28), CRANE (IAA18), WOODEN LEG, and ARABIDOPSIS RESPONSE REGULATORS1 (ARR1), ARR10, and ARR12. Vasculature proliferation also involves the cell cycle regulator KIP-RELATED PROTEIN2 and ABERRANT LATERAL ROOT FORMATION4, resulting in a mass of cells with rooting competence that resembles callus formation. Endogenous callus formation precedes specification of postembryonic root founder cells, from which roots are initiated through the activity of SHORT-ROOT, PLETHORA1 (PLT1), and PLT2. Primordia initiation is blocked in shr plt1 plt2 mutant. Stem cell regulators SCHIZORIZA, JACKDAW, BLUEJAY, and SCARECROW also participate in root initiation and are required to pattern the new organ, as mutants show disorganized and reduced number of layers and tissue initials resulting in reduced rooting. Our work provides an organ regeneration model through de novo root formation, stating key stages and the primary pathways involved. © 2018 American Society of Plant Biologists. All Rights Reserved.

Endodontic Treatment of an Anomalous Anterior Tooth with the Aid of a 3-dimensional Printed Physical Tooth Model.

PubMed

Byun, Chanhee; Kim, Changhwan; Cho, Seungryong; Baek, Seung Hoon; Kim, Gyutae; Kim, Sahng G; Kim, Sun-Young

2015-06-01

Endodontic treatment of tooth formation anomalies is a challenge to clinicians and as such requires a complete understanding of the aberrant root canal anatomy followed by careful root canal disinfection and obturation. Here, we report the use of a 3-dimensional (3D) printed physical tooth model including internal root canal structures for the endodontic treatment of a challenging tooth anomaly. A 12-year-old boy was referred for endodontic treatment of tooth #8. The tooth showed class II mobility with swelling and a sinus tract in the buccal mucosa and periapical radiolucency. The tooth presented a very narrow structure between the crown and root by distal concavity and a severely dilacerated root. Moreover, a perforation site with bleeding and another ditching site were identified around the cervical area in the access cavity. A translucent physical tooth model carrying the information on internal root canal structures was built through a 3-step process: data acquisition by cone-beam computed tomographic scanning, virtual modeling by image processing, and manufacturing by 3D printing. A custom-made guide jig was then fabricated to achieve a safe and precise working path to the root canal. Endodontic procedures including access cavity preparation were performed using the physical tooth model and the guide jig. At the 7-month follow-up, the endodontically treated tooth showed complete periapical healing with no clinical signs and symptoms. This case report describes a novel method of endodontic treatment of an anomalous maxillary central incisor with the aid of a physical tooth model and a custom-made guide jig via 3D printing technique. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Orthodontic Management with Traction and Asymmetric Extraction for Multiple Impacted Permanent Maxillary Teeth - A Case Report.

PubMed

Niu, Qiannan; Zhang, Liang; Dai, Juan; Li, Feifei; Feng, Xue

2016-01-01

Multiple impacted teeth are a rare eruption disturbance that increases the case complexity. In this article, we described a 13-year-old boy whose 5 permanent maxillary teeth were not erupted although their root formation was complete. The orthodontic treatment with traction and asymmetric extraction was performed to achieve a significantly improved functional and esthetic result.

Non-destructive digital imaging in poplar allows detailed analysis of adventitious rooting dynamics

Treesearch

R.J. Kodrzycki; R.B. Michaels; A.L. Friend; R.S. Zalesny; Ch.P. Mawata; D.W. McDonald

2008-01-01

The dynamics of root formation are difficult to observe directly over time without disturbing the rooting environment. A novel system for a non-destructive, non-invasive root analysis (RootViz FS, Phenotype Screening Corp.) was evaluated for its ability to analyze root formation from cuttings over a 32 day period in three poplar genotypes (DN70, P. Deltoides x...

Nitric oxide is the shared signalling molecule in phosphorus- and iron-deficiency-induced formation of cluster roots in white lupin (Lupinus albus)

PubMed Central

Meng, Zhi Bin; Chen, Li Qian; Suo, Dong; Li, Gui Xin; Tang, Cai Xian; Zheng, Shao Jian

2012-01-01

Background and Aims Formation of cluster roots is one of the most specific root adaptations to nutrient deficiency. In white lupin (Lupinus albus), cluster roots can be induced by phosphorus (P) or iron (Fe) deficiency. The aim of the present work was to investigate the potential shared signalling pathway in P- and Fe-deficiency-induced cluster root formation. Methods Measurements were made of the internal concentration of nutrients, levels of nitric oxide (NO), citrate exudation and expression of some specific genes under four P × Fe combinations, namely (1) 50 µm P and 10 µm Fe (+P + Fe); (2) 0 P and 10 µm Fe (–P + Fe); (3) 50 µm P and 0 Fe (+P–Fe); and (4) 0 P and 0 Fe (–P–Fe), and these were examined in relation to the formation of cluster roots. Key Results The deficiency of P, Fe or both increased the cluster root number and cluster zones. It also enhanced NO accumulation in pericycle cells and rootlet primordia at various stages of cluster root development. The formation of cluster roots and rootlet primordia, together with the expression of LaSCR1 and LaSCR2 which is crucial in cluster root formation, were induced by the exogenous NO donor S-nitrosoglutathione (GSNO) under the +P + Fe condition, but were inhibited by the NO-specific endogenous scavenger 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl- 3-oxide (cPTIO) under –P + Fe, +P–Fe and –P–Fe conditions. However, cluster roots induced by an exogenous supply of the NO donor did not secrete citrate, unlike those formed under –P or –Fe conditions. Conclusions NO plays an important role in the shared signalling pathway of the P- and Fe-deficiency-induced formation of cluster roots in white lupin. PMID:22351487

Enhanced formation of aerenchyma and induction of a barrier to radial oxygen loss in adventitious roots of Zea nicaraguensis contribute to its waterlogging tolerance as compared with maize (Zea mays ssp. mays).

PubMed

Abiko, Tomomi; Kotula, Lukasz; Shiono, Katsuhiro; Malik, Al Imran; Colmer, Timothy David; Nakazono, Mikio

2012-09-01

Enhancement of oxygen transport from shoot to root tip by the formation of aerenchyma and also a barrier to radial oxygen loss (ROL) in roots is common in waterlogging-tolerant plants. Zea nicaraguensis (teosinte), a wild relative of maize (Zea mays ssp. mays), grows in waterlogged soils. We investigated the formation of aerenchyma and ROL barrier induction in roots of Z. nicaraguensis, in comparison with roots of maize (inbred line Mi29), in a pot soil system and in hydroponics. Furthermore, depositions of suberin in the exodermis/hypodermis and lignin in the epidermis of adventitious roots of Z. nicaraguensis and maize grown in aerated or stagnant deoxygenated nutrient solution were studied. Growth of maize was more adversely affected by low oxygen in the root zone (waterlogged soil or stagnant deoxygenated nutrient solution) compared with Z. nicaraguensis. In stagnant deoxygenated solution, Z. nicaraguensis was superior to maize in transporting oxygen from shoot base to root tip due to formation of larger aerenchyma and a stronger barrier to ROL in adventitious roots. The relationships between the ROL barrier formation and suberin and lignin depositions in roots are discussed. The ROL barrier, in addition to aerenchyma, would contribute to the waterlogging tolerance of Z. nicaraguensis. © 2012 Blackwell Publishing Ltd.

Mevalonate kinase activity during different stages of plant regeneration from nodular callus cultures in white pine (Pinus strobus).

PubMed

Tang, Wei; Newton, Ronald J

2006-02-01

Mevalonate kinase (MK) catalyzes a step in the isoprenoid biosynthetic pathway, which leads to a huge number of compounds that play important roles in plant growth and development. Here, we report on changes in MK activity in white pine (Pinus strobus L.) during plant regeneration by adventitious shoot organogenesis from cotyledons of mature embryos, including nodular callus induction, shoot formation and rooting. Nodular calli were induced from Pinus strobus (PS) embryos by culture in nodular callus induction medium in a 0-, 8- or 16-h photoperiod. Mevalonate kinase activity peaked in nodular calli after three weeks of culture on nodular callus induction medium in a 16-h photoperiod, whereas frequency of nodular callus formation peaked after 4 weeks of culture on nodular callus induction medium in darkness. During adventitious shoot formation, MK activity peaked in shoots derived from dark-grown nodular calli after 3 weeks on bud formation medium, and frequency of shoot formation was highest in dark-grown nodular calli cultured on bud formation medium for 4 weeks. During rooting, MK activity peaked 2 weeks after transfer of adventitious shoots to rooting medium and rooting frequency was highest in adventitious shoots after 3 weeks on rooting medium. Although during nodular callus induction in darkness MK activity was inversely related to frequency of nodular callus formation, MK activity was highly correlated with frequency of shoot formation and with rooting frequency. The observed increase in MK activity preceding rooting suggests that MK could serve as a marker for rooting of white pine shoots in vitro.

Cell wall properties play an important role in the emergence of lateral root primordia from the parent root.

PubMed

Roycewicz, Peter S; Malamy, Jocelyn E

2014-05-01

Plants adapt to their unique soil environments by altering the number and placement of lateral roots post-embryonic. Mutants were identified in Arabidopsis thaliana that exhibit increased lateral root formation. Eight mutants were characterized in detail and were found to have increased lateral root formation due to at least three distinct mechanisms. The causal mutation in one of these mutants was found in the XEG113 gene, recently shown to be involved in plant cell wall biosynthesis. Lateral root primordia initiation is unaltered in this mutant. In contrast, synchronization of lateral root initiation demonstrated that mutation of XEG113 increases the rate at which lateral root primordia develop and emerge to form lateral roots. The effect of the XEG113 mutation was specific to the root system and had no apparent effect on shoot growth. Screening of 17 additional cell wall mutants, altering a myriad of cell wall components, revealed that many (but not all) types of cell wall defects promote lateral root formation. These results suggest that proper cell wall biosynthesis is necessary to constrain lateral root primordia emergence. While previous reports have shown that lateral root emergence is accompanied by active remodelling of cell walls overlying the primordia, this study is the first to demonstrate that alteration of the cell wall is sufficient to promote lateral root formation. Therefore, inherent cell wall properties may play a previously unappreciated role in regulation of root system architecture.

Control of root meristem establishment in conifers.

PubMed

Brunoni, Federica; Ljung, Karin; Bellini, Catherine

2018-06-19

The evolution of terrestrial plant life was made possible by the establishment of a root system, which enabled plants to migrate from aquatic to terrestrial habitats. During evolution, root organization has gradually progressed from a very simple to a highly hierarchical architecture. Roots are initiated during embryogenesis and branch afterwards through lateral root formation. Additionally, adventitious roots can be formed post-embryonically from aerial organs. Induction of adventitious roots forms the basis of the vegetative propagation via cuttings in horticulture, agriculture and forestry. This method, together with somatic embryogenesis, is routinely used to clonally multiply conifers. In addition to being utilized as propagation techniques, adventitious rooting and somatic embryogenesis have emerged as versatile models to study cellular and molecular mechanisms of embryo formation and organogenesis of coniferous species. Both formation of the embryonic root and the adventitious root primordia require the establishment of auxin gradients within cells that coordinate the developmental response. These processes also share key elements of the genetic regulatory networks that, for example, are triggering cell fate. This minireview gives an overview of the molecular control mechanisms associated with root development in conifers, from initiation in the embryo to post-embryonic formation in cuttings. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The Starvation Resistance and Biofilm Formation of Enterococcus faecalis in Coexistence with Candida albicans, Streptococcus gordonii, Actinomyces viscosus, or Lactobacillus acidophilus.

PubMed

Gao, Yan; Jiang, Xiaoqiong; Lin, Dongjia; Chen, Yanhuo; Tong, Zhongchun

2016-08-01

Enterococcus faecalis is the most frequently detected species in root canal-treated teeth, and it is able to survive under starvation conditions. However, persistent periapical disease is often caused by multispecies. The aim of this study was to explore the survival of E. faecalis in starvation conditions and biofilm formation with the 4 common pathogenic species. A dual-species model of Candida albicans, Streptococcus gordonii, Actinomyces viscosus, or Lactobacillus acidophilus in combination with E. faecalis was established and allowed to grow in phosphate-buffered saline for the examination of starvation survival. Cefuroxime sodium and vancomycin at a concentration of 100 mg/L were added into brain-heart infusion plate agar to count the 2 bacteria separately in the dual species. Scanning electron microscopy was used to observe the dual species and multiple species on the root canal dentin of bovine teeth for 48 hours. A confocal laser scanning microscope was used to show the 4 groups of dual-species biofilms on substrates with glass bottoms for 48 hours. E. faecalis was more resistant to starvation in coexistence with C. albicans, S. gordonii, A. viscosus, or L. acidophilus, and S. gordonii was completely inhibited in coexistence with E. faecalis. The dual-species biofilm showed that E. faecalis formed thicker and denser biofilms on the root canal dentin and glass slides in coexistence with S. gordonii and A. viscosus than C. albicans and L. acidophilus. The multispecies community is conducive to the resistance to starvation of E. faecalis and biofilm formation in root canals. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The Arabidopsis DCR Encoding a Soluble BAHD Acyltransferase Is Required for Cutin Polyester Formation and Seed Hydration Properties1[C][W][OA

PubMed Central

Panikashvili, David; Shi, Jian Xin; Schreiber, Lukas; Aharoni, Asaph

2009-01-01

The cuticle covering every plant aerial organ is largely made of cutin that consists of fatty acids, glycerol, and aromatic monomers. Despite the huge importance of the cuticle to plant development and fitness, our knowledge regarding the assembly of the cutin polymer and its integration in the complete cuticle structure is limited. Cutin composition implies the action of acyltransferase-type enzymes that mediate polymer construction through ester bond formation. Here, we show that a member of the BAHD family of acyltransferases (DEFECTIVE IN CUTICULAR RIDGES [DCR]) is required for incorporation of the most abundant monomer into the polymeric structure of the Arabidopsis (Arabidopsis thaliana) flower cutin. DCR-deficient plants display phenotypes that are typically associated with a defective cuticle, including altered epidermal cell differentiation and postgenital organ fusion. Moreover, levels of the major cutin monomer in flowers, 9(10),16-dihydroxy-hexadecanoic acid, decreased to an almost undetectable amount in the mutants. Interestingly, dcr mutants exhibit changes in the decoration of petal conical cells and mucilage extrusion in the seed coat, both phenotypes formerly not associated with cutin polymer assembly. Excessive root branching displayed by dcr mutants and the DCR expression pattern in roots pointed to the function of DCR belowground, in shaping root architecture by influencing lateral root emergence and growth. In addition, the dcr mutants were more susceptible to salinity, osmotic, and water deprivation stress conditions. Finally, the analysis of DCR protein localization suggested that cutin polymerization, possibly the oligomerization step, is partially carried out in the cytoplasmic space. Therefore, this study extends our knowledge regarding the functionality of the cuticular layer and the formation of its major constituent the polymer cutin. PMID:19828672

The Arabidopsis DCR encoding a soluble BAHD acyltransferase is required for cutin polyester formation and seed hydration properties.

PubMed

Panikashvili, David; Shi, Jian Xin; Schreiber, Lukas; Aharoni, Asaph

2009-12-01

The cuticle covering every plant aerial organ is largely made of cutin that consists of fatty acids, glycerol, and aromatic monomers. Despite the huge importance of the cuticle to plant development and fitness, our knowledge regarding the assembly of the cutin polymer and its integration in the complete cuticle structure is limited. Cutin composition implies the action of acyltransferase-type enzymes that mediate polymer construction through ester bond formation. Here, we show that a member of the BAHD family of acyltransferases (DEFECTIVE IN CUTICULAR RIDGES [DCR]) is required for incorporation of the most abundant monomer into the polymeric structure of the Arabidopsis (Arabidopsis thaliana) flower cutin. DCR-deficient plants display phenotypes that are typically associated with a defective cuticle, including altered epidermal cell differentiation and postgenital organ fusion. Moreover, levels of the major cutin monomer in flowers, 9(10),16-dihydroxy-hexadecanoic acid, decreased to an almost undetectable amount in the mutants. Interestingly, dcr mutants exhibit changes in the decoration of petal conical cells and mucilage extrusion in the seed coat, both phenotypes formerly not associated with cutin polymer assembly. Excessive root branching displayed by dcr mutants and the DCR expression pattern in roots pointed to the function of DCR belowground, in shaping root architecture by influencing lateral root emergence and growth. In addition, the dcr mutants were more susceptible to salinity, osmotic, and water deprivation stress conditions. Finally, the analysis of DCR protein localization suggested that cutin polymerization, possibly the oligomerization step, is partially carried out in the cytoplasmic space. Therefore, this study extends our knowledge regarding the functionality of the cuticular layer and the formation of its major constituent the polymer cutin.

An NADPH Oxidase RBOH Functions in Rice Roots during Lysigenous Aerenchyma Formation under Oxygen-Deficient Conditions

PubMed Central

Yoshioka, Miki; Fukazawa, Aya; Nishizawa, Naoko K.

2017-01-01

Reactive oxygen species (ROS) produced by the NADPH oxidase, respiratory burst oxidase homolog (RBOH), trigger signal transduction in diverse biological processes in plants. However, the functions of RBOH homologs in rice (Oryza sativa) and other gramineous plants are poorly understood. Ethylene induces the formation of lysigenous aerenchyma, which consists of internal gas spaces created by programmed cell death of cortical cells, in roots of gramineous plants under oxygen-deficient conditions. Here, we report that, in rice, one RBOH isoform (RBOHH) has a role in ethylene-induced aerenchyma formation in roots. Induction of RBOHH expression under oxygen-deficient conditions was greater in cortical cells than in cells of other root tissues. In addition, genes encoding group I calcium-dependent protein kinases (CDPK5 and CDPK13) were strongly expressed in root cortical cells. Coexpression of RBOHH with CDPK5 or CDPK13 induced ROS production in Nicotiana benthamiana leaves. Inhibitors of RBOH activity or cytosolic calcium influx suppressed ethylene-induced aerenchyma formation. Moreover, knockout of RBOHH by CRISPR/Cas9 reduced ROS accumulation and inducible aerenchyma formation in rice roots. These results suggest that RBOHH-mediated ROS production, which is stimulated by CDPK5 and/or CDPK13, is essential for ethylene-induced aerenchyma formation in rice roots under oxygen-deficient conditions. PMID:28351990

Effect of medium composition and light on root and rhinacanthin formation in Rhinacanthus nasutus cultures.

PubMed

Panichayupakaranant, P; Meerungrueang, W

2010-11-01

Rhinacanthus nasutus (L.) Kurz (Acanthaceae) has long been used in Thai traditional medicine for treatment of tinea versicolor, ringworm, pruritic rash, and abscess. The active constituents are known as a group of naphthoquinone esters, rhinacanthins. This work focused on establishment of R. nasutus root cultures and determination of rhinacanthin production. Induction of R. nasutus root formation was accomplished on solid Gamborg's B5 (B5) medium, supplied with 0.1 mg/L indole-3-butyric acid (IBA) and 20 g/L sucrose. The effects of explants (whole leaf explants and four-side excised leaf explants), light and medium composition on root and rhinacanthin formation were investigated. The root formation from the whole leaf explants was 10 times higher than that from the four-side excised leaf explants. In addition, light possessed an inhibitory effect on the root and rhinacanthin formation of R. nasutus. Medium manipulation found that Murashige and Skoog (MS) medium supplied with 3 mg/L IBA and 30 g/L sucrose was the most suitable for induction of the root formation. Unfortunately, the obtained root cultures produced only rhinacanthin-C in very low amount, 0.026 mg/g dry weight (DW), when they were transferred into the same MS liquid medium. With semisolid medium (4 g/L agar) of the same MS composition, however, the root cultures appeared to produce higher content of rhinacanthin-C, -D and -N (3.45, 0.07 and 0.07 mg/g DW, respectively). Our finding suggests that culturing in semisolid medium is capable of improving of rhinacanthin production in R. nasutus root cultures.

Knockdown of the partner protein OsNAR2.1 for high-affinity nitrate transport represses lateral root formation in a nitrate-dependent manner

PubMed Central

Huang, Shuangjie; Chen, Si; Liang, Zhihao; Zhang, Chenming; Yan, Ming; Chen, Jingguang; Xu, Guohua; Fan, Xiaorong; Zhang, Yali

2015-01-01

The morphological plasticity of root systems is critical for plant survival, and understanding the mechanisms underlying root adaptation to nitrogen (N) fluctuation is critical for sustainable agriculture; however, the molecular mechanism of N-dependent root growth in rice remains unclear. This study aimed to identify the role of the complementary high-affinity NO3− transport protein OsNAR2.1 in NO3−-regulated rice root growth. Comparisons with wild-type (WT) plants showed that knockdown of OsNAR2.1 inhibited lateral root (LR) formation under low NO3− concentrations, but not under low NH4+ concentrations. 15N-labelling NO3− supplies (provided at concentrations of 0–10 mM) demonstrated that (i) defects in LR formation in mutants subjected to low external NO3− concentrations resulted from impaired NO3− uptake, and (ii) the mutants had significantly fewer LRs than the WT plants when root N contents were similar between genotypes. LR formation in osnar2.1 mutants was less sensitive to localised NO3− supply than LR formation in WT plants, suggesting that OsNAR2.1 may be involved in a NO3−-signalling pathway that controls LR formation. Knockdown of OsNAR2.1 inhibited LR formation by decreasing auxin transport from shoots to roots. Thus, OsNAR2.1 probably functions in both NO3− uptake and NO3−-signalling. PMID:26644084

The effects of exogenous hormones on rooting process and the activities of key enzymes of Malus hupehensis stem cuttings.

PubMed

Zhang, Wangxiang; Fan, Junjun; Tan, Qianqian; Zhao, Mingming; Zhou, Ting; Cao, Fuliang

2017-01-01

Malus hupehensis is an excellent Malus rootstock species, known for its strong adverse-resistance and apomixes. In the present study, stem cuttings of M. hupehensis were treated with three types of exogenous hormones, including indole acetic acid (IAA), naphthalene acetic acid (NAA), or green growth regulator (GGR). The effects and mechanisms of exogenous hormone treatment and antioxidant enzyme activity on adventitious root formation were investigated. The results showed that the apparent morphology of the adventitious root had four stages, including root pre-emergence stage (S0), early stage of root formation (S1), massive root formation stage (S2), and later stage of root formation (S3). The suitable concentrations of the three exogenous hormones, IAA, NAA and GGR, were 100 mg·L-1, 300 mg·L-1, and 300 mg·L-1, respectively. They shortened the rooting time by 25-47.4% and increased the rooting percentages of cuttings by 0.9-1.3 times, compared with that in the control. The dispersion in S0 stage was 3.6 times of that in the S1 stage after exogenous hormone application. The earlier the third critical point (P3) appeared, the shorter the rooting time and the greater the rooting percentage of the cuttings. During rhizogenesis, the activities of three antioxidant enzymes (POD, SOD, and PPO) showed an A-shaped trend. However, peak values of enzyme activity appeared at different points, which were 9 d before the P3, P3, and the fourth critical point (P4), respectively. Exogenous hormone treatment reduced the time to reach the peak value by 18 days, although the peak values of the enzymatic activities did not significantly changed. Our results suggested that exogenous hormone treatment mainly acted during the root pre-emergence stage, accelerated the synthesis of antioxidant enzymes, reduced the rooting time, and consequently promoted root formation. The three kinds of antioxidant enzymes acted on different stages of rooting.

A Bacillus subtilis Sensor Kinase Involved in Triggering Biofilm Formation on the Roots of Tomato Plants

PubMed Central

Chen, Yun; Cao, Shugeng; Chai, Yunrong; Clardy, Jon; Kolter, Roberto; Guo, Jian-hua; Losick, Richard

2012-01-01

SUMMARY The soil bacterium Bacillus subtilis is widely used in agriculture as a biocontrol agent able to protect plants from a variety of pathogens. Protection is thought to involve the formation of bacterial communities - biofilms - on the roots of the plants. Here we used confocal microscopy to visualize biofilms on the surface of the roots of tomato seedlings and demonstrated that biofilm formation requires genes governing the production of the extracellular matrix that holds cells together. We further show that biofilm formation was dependent on the sensor histidine kinase KinD and in particular on an extracellular CACHE domain implicated in small molecule sensing. Finally, we report that exudates of tomato roots strongly stimulated biofilm formation ex planta and that an abundant small molecule in the exudates, l-malic acid, was able to stimulate biofilm formation at high concentrations in a manner that depended on the KinD CACHE domain. We propose that small signaling molecules released by the roots of tomato plants are directly or indirectly recognized by KinD, triggering biofilm formation. PMID:22716461

[Morphogenesis in formative process in vitro from Rehmannia glutinosa].

PubMed

Xue, Jian-ping; Zhang, Ai-min; Liu, Jun; Xu, Xue-feng

2004-01-01

To study the morphogenesis in formative process of tuberous root in vitro from Rehmannia glutinosa and compare the anatomical shape of tuberous root with nature term R. glutinosa. Tuberous roots of different vegetal phase were cut and dyed, then made into paraffin cuts and observed microscope. In anatomical shape, nature R. glutinosa and tuberous root were the same, which showed that no structural variation occurred in tuberous root induced process.

Severe root resorption resulting from orthodontic treatment: Prevalence and risk factors

PubMed Central

Maués, Caroline Pelagio Raick; do Nascimento, Rizomar Ramos; Vilella, Oswaldo de Vasconcellos

2015-01-01

OBJECTIVE: To assess the prevalence of severe external root resorption and its potential risk factors resulting from orthodontic treatment. METHODS: A randomly selected sample was used. It comprised conventional periapical radiographs taken in the same radiology center for maxillary and mandibular incisors before and after active orthodontic treatment of 129 patients, males and females, treated by means of the Standard Edgewise technique. Two examiners measured and defined root resorption according to the index proposed by Levander et al. The degree of external apical root resorption was registered defining resorption in four degrees of severity. To assess intra and inter-rater reproducibility, kappa coefficient was used. Chi-square test was used to assess the relationship between the amount of root resorption and patient's sex, dental arch (maxillary or mandibular), treatment with or without extractions, treatment duration, root apex stage (open or closed), root shape, as well as overjet and overbite at treatment onset. RESULTS: Maxillary central incisors had the highest percentage of severe root resorption, followed by maxillary lateral incisors and mandibular lateral incisors. Out of 959 teeth, 28 (2.9%) presented severe root resorption. The following risk factors were observed: anterior maxillary teeth, overjet greater than or equal to 5 mm at treatment onset, treatment with extractions, prolonged therapy, and degree of apex formation at treatment onset. CONCLUSION: This study showed that care must be taken in orthodontic treatment involving extractions, great retraction of maxillary incisors, prolonged therapy, and/or completely formed apex at orthodontic treatment onset. PMID:25741825

Severe root resorption resulting from orthodontic treatment: prevalence and risk factors.

PubMed

Maués, Caroline Pelagio Raick; do Nascimento, Rizomar Ramos; Vilella, Oswaldo de Vasconcellos

2015-01-01

To assess the prevalence of severe external root resorption and its potential risk factors resulting from orthodontic treatment. A randomly selected sample was used. It comprised conventional periapical radiographs taken in the same radiology center for maxillary and mandibular incisors before and after active orthodontic treatment of 129 patients, males and females, treated by means of the Standard Edgewise technique. Two examiners measured and defined root resorption according to the index proposed by Levander et al. The degree of external apical root resorption was registered defining resorption in four degrees of severity. To assess intra and inter-rater reproducibility, kappa coefficient was used. Chi-square test was used to assess the relationship between the amount of root resorption and patient's sex, dental arch (maxillary or mandibular), treatment with or without extractions, treatment duration, root apex stage (open or closed), root shape, as well as overjet and overbite at treatment onset. Maxillary central incisors had the highest percentage of severe root resorption, followed by maxillary lateral incisors and mandibular lateral incisors. Out of 959 teeth, 28 (2.9%) presented severe root resorption. The following risk factors were observed: anterior maxillary teeth, overjet greater than or equal to 5 mm at treatment onset, treatment with extractions, prolonged therapy, and degree of apex formation at treatment onset. This study showed that care must be taken in orthodontic treatment involving extractions, great retraction of maxillary incisors, prolonged therapy, and/or completely formed apex at orthodontic treatment onset.

Effects of Meloidogyne incognita on Growth and Storage-Root Formation of Cassava (Manihot esculenta)

PubMed Central

Makumbi-Kidza, N. N.; Speijer, P. R.; Sikora, R. A.

2000-01-01

Two-node cuttings of cassava cultivar SS4 were inoculated with 1,000 infective juveniles of Meloidogyne incognita at 1, 14, 40, 70, 88, and 127 days after planting (DAP). Plant growth and root damage were assessed at 150 DAP. Meloidogyne incognita significantly reduced the number of storageroots formed in plants inoculated at 14, 40, 70, and 88 DAP and the total weight of storage-roots in plants inoculated at 1, 14, 40, 70, and 88 DAP, compared to uninoculated plants. Individual storage-root weight and plant height were not affected by M. incognita. Storage-root formation in cassava is initiated when plants are 1 to 2 months old. The results of this experiment indicate that, at this time, young cassava plants are most prone to root-knot nematode damage in terms of storage-root formation. The production loss caused by M. incognita to young SS4 plants was due to a reduction of storage-root number rather than a reduction in individual storage-root weight. PMID:19270997

Over-expression of mango (Mangifera indica L.) MiARF2 inhibits root and hypocotyl growth of Arabidopsis.

PubMed

Wu, Bei; Li, Yun-He; Wu, Jian-Yong; Chen, Qi-Zhu; Huang, Xia; Chen, Yun-Feng; Huang, Xue-Lin

2011-06-01

An auxin response factor 2 gene, MiARF2, was cloned in our previous study [1] from the cotyledon section of mango (Mangifera indica L. cv. Zihua) during adventitious root formation, which shares an 84% amino acid sequence similarity to Arabidopsis ARF2. This study was to examine the effects of over-expression of the full-length MiARF2 open reading frame on the root and hypocotyl growth in Arabidopsis. Phenotype analysis showed that the T(3) transgenic lines had about 20-30% reduction in the length of hypocotyls and roots of the seedlings in comparison with the wild-type. The transcription levels of ANT and ARGOS genes which play a role in controlling organ size and cell proliferation in the transgenic seedlings also decreased. Therefore, the inhibited root and hypocotyl growth in the transgenic seedlings may be associated with the down-regulated transcription of ANT and ARGOS by the over-expression of MiARF2. This study also suggests that although MiARF2 only has a single DNA-binding domain (DBD), it can function as other ARF-like proteins containing complete DBD, middle region (MR) and carboxy-terminal dimerization domain (CTD).

Organic acids from root exudates of banana help root colonization of PGPR strain Bacillus amyloliquefaciens NJN-6

PubMed Central

Yuan, Jun; Zhang, Nan; Huang, Qiwei; Raza, Waseem; Li, Rong; Vivanco, Jorge M.; Shen, Qirong

2015-01-01

The successful colonization of plant growth promoting rhizobacteria (PGPR) in the rhizosphere is an initial and compulsory step in the protection of plants from soil-borne pathogens. Therefore, it is necessary to evaluate the role of root exudates in the colonization of PGPR. Banana root exudates were analyzed by high pressure liquid chromatography (HPLC) which revealed exudates contained several organic acids (OAs) including oxalic, malic and fumaric acid. The chemotactic response and biofilm formation of Bacillus amyloliquefaciens NJN-6 were investigated in response to OA’s found in banana root exudates. Furthermore, the transcriptional levels of genes involved in biofilm formation, yqxM and epsD, were evaluated in response to OAs via quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Results suggested that root exudates containing the OAs both induced the chemotaxis and biofilm formation in NJN-6. In fact, the strongest chemotactic and biofilm response was found when 50 μM of OAs were applied. More specifically, malic acid showed the greatest chemotactic response whereas fumaric acid significantly induced biofilm formation by a 20.7–27.3% increase and therefore biofilm formation genes expression. The results showed banana root exudates, in particular the OAs released, play a crucial role in attracting and initiating PGPR colonization on the host roots. PMID:26299781

Comparison of Quick-Set and mineral trioxide aggregate root-end fillings for the regeneration of apical tissues in dogs.

PubMed

Kohout, George D; He, Jianing; Primus, Carolyn M; Opperman, Lynne A; Woodmansey, Karl F

2015-02-01

Quick-Set (Avalon Biomed Inc, Bradenton, FL) is a calcium aluminosilicate cement that is a potential alternative to mineral trioxide aggregate (MTA) with greater acid resistance and faster setting. The purpose of this study was to compare the regeneration of apical tissues after root-end surgery when the apical tissues were exposed to Quick-Set or White ProRoot MTA (Dentsply Tulsa Dental Specialties, Tulsa, OK) by root-end resection. The root canals of 42 mandibular premolars in 7 beagle dogs were accessed, cleaned and shaped, and obturated with Quick-Set or white MTA. Osteotomies and root-end resections were performed immediately. The dogs were sacrificed at 90 days, and the teeth and surrounding tissues were removed and prepared for histologic analysis. The sections of the apical areas were scored for inflammation, new cementum formation, periodontal ligament formation, and bone quality. At 90 days, both materials supported some degree of cementum formation on the surface of the material, periodontal ligament regeneration, and excellent bone quality. The only significant difference was greater inflammation found in the Quick-Set group. Quick-Set and White ProRoot MTA had a similar effect on bone quality, cementum formation, and periodontal ligament formation after root-end surgery in dogs. Quick-Set was associated with greater inflammation. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The effect of complete radial lateral meniscus posterior root tear on the knee contact mechanics: a finite element analysis.

PubMed

Bao, H R C; Zhu, D; Gong, H; Gu, G S

2013-03-01

In recent years, with technological advances in arthroscopy and magnetic resonance imaging and improved biomechanical studies of the meniscus, there has been some progress in the diagnosis and treatment of injuries to the roots of the meniscus. However, the biomechanical effect of posterior lateral meniscus root tears on the knee has not yet become clear. The purpose of this study was to determine the effect of a complete radial posterior lateral meniscus root tear on the knee contact mechanics and the function of the posterior meniscofemoral ligament on the knee with tear in the posterior root of lateral meniscus. A finite element model of the knee was developed to simulate different cases for intact knee, a complete radial posterior lateral meniscus root tear, a complete radial posterior lateral meniscus root tear with posterior meniscofemoral ligament deficiency, and total meniscectomy of the lateral meniscus. A compressive load of 1000 N was applied in all cases to calculate contact areas, contact pressure, and meniscal displacements. The complete radial posterior lateral meniscus root tear decreased the contact area and increased the contact pressure on the lateral compartment under compressive load. We also found a decreased contact area and increased contact pressure in the medial compartment, but it was not obvious compared to the lateral compartment. The lateral meniscus was radially displaced by compressive load after a complete radial posterior lateral meniscus root tear, and the displacement took place mainly in the body and posterior horn of lateral meniscus. There were further decrease in contact area and increases in contact pressure and raidial displacement of the lateral meniscus in the case of the complete posterior lateral meniscus root tear in combination with posterior meniscofemoral ligament deficiency. Complete radial posterior lateral meniscus root tear is not functionally equivalent to total meniscectomy. The posterior root torn lateral meniscus continues to provide some load transmission and distribution functions across the joint. The posterior meniscofemoral ligament prevents excessive radial displacement of the posterior root torn lateral meniscus and assists the torn lateral meniscus in transmitting a certain amount of stress in the lateral compartment.

Hormone-Mediated Pattern Formation in Seedling of Plants: a Competitive Growth Dynamics Model

NASA Astrophysics Data System (ADS)

Kawaguchi, Satoshi; Mimura, Masayasu; Ohya, Tomoyuki; Oikawa, Noriko; Okabe, Hirotaka; Kai, Shoichi

2001-10-01

An ecologically relevant pattern formation process mediated by hormonal interactions among growing seedlings is modeled based on the experimental observations on the effects of indole acetic acid, which can act as an inhibitor and activator of root growth depending on its concentration. In the absence of any lateral root with constant hormone-sensitivity, the edge effect phenomenon is obtained depending on the secretion rate of hormone from the main root. Introduction of growth-stage-dependent hormone-sensitivity drastically amplifies the initial randomness, resulting in spatially irregular macroscopic patterns. When the lateral root growth is introduced, periodic patterns are obtained whose periodicity depends on the length of lateral roots. The growth-stage-dependent hormone-sensitivity and the lateral root growth are crucial for macroscopic periodic-pattern formation.

In vitro cultured primary roots derived from stem segments of cassava (Manihot esculenta) can behave like storage organs.

PubMed

Medina, Ricardo D; Faloci, Mirta M; Gonzalez, Ana M; Mroginski, Luis A

2007-03-01

Cassava (Manihot esculenta) has three adventitious root types: primary and secondary fibrous roots, and storage roots. Different adventitious root types can also regenerate from in vitro cultured segments. The aim of this study was to investigate aspects of in vitro production of storage roots. Morphological and anatomical analyses were performed to identify and differentiate each root type. Twenty-nine clones were assayed to determine the effect of genotype on the capacity to form storage roots in vitro. The effects of cytokinins and auxins on the formation of storage roots in vitro were also examined. Primary roots formed in vitro and in vivo had similar tissue kinds; however, storage roots formed in vitro exhibited physiological specialization for storing starch. The only consistent diagnostic feature between secondary fibrous and storage roots was their functional differentiation. Anatomical analysis of the storage roots formed in vitro showed that radial expansion as a consequence of massive proliferation and enlargement of parenchymatous cells occurred in the middle cortex, but not from cambial activity as in roots formed in vivo. Cortical expansion could be related to dilatation growth favoured by hormone treatments. Starch deposition of storage roots formed in vitro was confined to cortical tissue and occurred earlier than in storage roots formed in vivo. Auxin and cytokinin supplementation were absolutely required for in vitro storage root regeneration; these roots were not able to develop secondary growth, but formed a tissue competent for starch storing. MS medium with 5 % sucrose plus 0.54 microM 1-naphthaleneacetic acid and 0.44 microM 6-benzylaminopurine was one of the most effective in stimulating the storage root formation. Genotypes differed significantly in their capacity to produce storage roots in vitro. Storage root formation was considerably affected by the segment's primary position and strongly influenced by hormone treatments. The storage root formation system reported here is a first approach to develop a tuberization model, and additional efforts are required to improve it. Although it was not possible to achieve root secondary growth, after this work it will be feasible to advance in some aspects of in vitro cassava tuberization.

Genetic and Phenotypic Analysis of Lateral Root Development in Arabidopsis thaliana.

PubMed

Napsucialy-Mendivil, Selene; Dubrovsky, Joseph G

2018-01-01

Root system formation to a great extent depends on lateral root (LR) formation. In Arabidopsis thaliana, LRs are initiated within a parent root in pericycle that is an external tissue of the stele. LR initiation takes place in a strictly acropetal pattern, whereas posterior lateral root primordium (LRP) formation is asynchronous. In this chapter, we focus on methods of genetic and phenotypic analysis of LR initiation, LRP morphogenesis, and LR emergence in Arabidopsis. We provide details on how to make cleared root preparations and how to identify the LRP stages. We also pay attention to the categorization of the LRP developmental stages and their variations and to the normalization of the number of LRs and LRPs formed, per length of the primary root, and per number of cells produced within a root. Hormonal misbalances and mutations affect LRP morphogenesis significantly, and the evaluation of LRP abnormalities is addressed as well. Finally, we deal with various molecular markers that can be used for genetic and phenotypic analyses of LR development.

Nitric oxide enhances development of lateral roots in tomato (Solanum lycopersicum L.) under elevated carbon dioxide.

PubMed

Wang, Huan; Xiao, Wendan; Niu, Yaofang; Jin, Chongwei; Chai, Rushan; Tang, Caixian; Zhang, Yongsong

2013-01-01

Elevated carbon dioxide (CO₂) has been shown to enhance the growth and development of plants, especially of roots. Amongst them, lateral roots play an important role in nutrient uptake, and thus alleviate the nutrient limitation to plant growth under elevated CO₂. This paper examined the mechanism underlying CO₂ elevation-induced lateral root formation in tomato. The endogenous nitric oxide (NO) in roots was detected by the specific probe 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA). We suggest that CO₂ elevation-induced NO accumulation was important for lateral root formation. Elevated CO₂ significantly increased the activity of nitric oxide synthase in roots, but not nitrate reductase activity. Moreover, the pharmacological evidence showed that nitric oxide synthase rather than nitrate reductase was responsible for CO₂ elevation-induced NO accumulation. Elevated CO₂ enhanced the activity of nitric oxide synthase and promoted production of NO, which was involved in lateral root formation in tomato under elevated CO₂.

Specific plant induced biofilm formation in Methylobacterium species.

PubMed

Rossetto, Priscilla B; Dourado, Manuella N; Quecine, Maria C; Andreote, Fernando D; Araújo, Welington L; Azevedo, João L; Pizzirani-Kleiner, Aline A

2011-07-01

Two endophytic strains of Methylobacterium spp. were used to evaluate biofilm formation on sugarcane roots and on inert wooden sticks. Results show that biofilm formation is variable and that plant surface and possibly root exudates have a role in Methylobacterium spp. host recognition, biofilm formation and successful colonization as endophytes.

The effects of exogenous hormones on rooting process and the activities of key enzymes of Malus hupehensis stem cuttings

PubMed Central

Tan, Qianqian; Zhao, Mingming; Zhou, Ting; Cao, Fuliang

2017-01-01

Malus hupehensis is an excellent Malus rootstock species, known for its strong adverse-resistance and apomixes. In the present study, stem cuttings of M. hupehensis were treated with three types of exogenous hormones, including indole acetic acid (IAA), naphthalene acetic acid (NAA), or green growth regulator (GGR). The effects and mechanisms of exogenous hormone treatment and antioxidant enzyme activity on adventitious root formation were investigated. The results showed that the apparent morphology of the adventitious root had four stages, including root pre-emergence stage (S0), early stage of root formation (S1), massive root formation stage (S2), and later stage of root formation (S3). The suitable concentrations of the three exogenous hormones, IAA, NAA and GGR, were 100 mg·L-1, 300 mg·L-1, and 300 mg·L-1, respectively. They shortened the rooting time by 25–47.4% and increased the rooting percentages of cuttings by 0.9–1.3 times, compared with that in the control. The dispersion in S0 stage was 3.6 times of that in the S1 stage after exogenous hormone application. The earlier the third critical point (P3) appeared, the shorter the rooting time and the greater the rooting percentage of the cuttings. During rhizogenesis, the activities of three antioxidant enzymes (POD, SOD, and PPO) showed an A-shaped trend. However, peak values of enzyme activity appeared at different points, which were 9 d before the P3, P3, and the fourth critical point (P4), respectively. Exogenous hormone treatment reduced the time to reach the peak value by 18 days, although the peak values of the enzymatic activities did not significantly changed. Our results suggested that exogenous hormone treatment mainly acted during the root pre-emergence stage, accelerated the synthesis of antioxidant enzymes, reduced the rooting time, and consequently promoted root formation. The three kinds of antioxidant enzymes acted on different stages of rooting. PMID:28231330

Inhibitory effects of Japanese horseradish (Wasabia japonica) on the formation and genotoxicity of a potent carcinogen, acrylamide.

PubMed

Shimamura, Yuko; Iio, Misako; Urahira, Tomoko; Masuda, Shuichi

2017-06-01

The formation of acrylamide (AA) in cooked foods has raised human health concerns. AA is metabolized by cytochrome P450 2E1 (CYP2E1) to glycidamide (GA), which forms DNA adducts. This study examined the inhibitory effects of wasabi (Japanese horseradish, Wasabia japonica) roots and leaves as well as their active component, allyl isothiocyanate (AIT), on the formation and genotoxicity of AA. AA formation (51.8 ± 4.2 µg kg -1 ) was inhibited with ≥2 mg mL -1 of AIT. Wasabi roots also inhibited AA formation (∼90% reduction), but wasabi leaves were not effective at 2 mg mL -1 . Wasabi roots and leaves decreased the number of cells with micronuclei by approximately 33 and 24% respectively compared with the AA treatment group. Moreover, wasabi roots and leaves (100 mg kg -1 body weight (BW) day -1 for each) decreased AA (100 mg kg -1 BW day -1 )-induced DNA damage. The AA-induced CYP2E1 activity was decreased by 39 and 26% with wasabi roots and leaves respectively. Further, the activity of glutathione S-transferase, which catalyzes the detoxification of AA via glutathione conjugation, increased by 54 and 33% with wasabi roots and leaves respectively. These results indicate that wasabi roots and leaves are effective ingredients for inhibiting the formation and genotoxicity of AA. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

A Review and Conceptual Model of Factors Correlated with Postmortem Root Band Formation.

PubMed

Donfack, Joseph; Castillo, Hilda S

2018-03-12

It is generally accepted within the forensic trace evidence community that a postmortem root band (PMRB) can appear in the root of hairs attached to remains during decomposition. Presently, the specific sequences of events and/or exact molecular signals that lead to the formation of a PMRB are not well understood. The published literature addressing the abiotic and biotic factors that correlate with the formation of PMRBs is reviewed and a conceptual model for the formation of PMRBs is proposed. © 2018 American Academy of Forensic Sciences.

Adventitious Root Formation of Forest Trees and Horticultural Plants - From Genes to Applications

USDA-ARS?s Scientific Manuscript database

Adventitious root formation is a key step in the clonal propagation of forest trees and horticultural crops. Difficulties in forming adventitious roots (ARs) on stem cuttings and plants produced in vitro hinders the propagation of elite trees and efficient production of many horticultural plant spec...

Mitochondrial β-Cyanoalanine Synthase Is Essential for Root Hair Formation in Arabidopsis thaliana[W

PubMed Central

García, Irene; Castellano, José María; Vioque, Blanca; Solano, Roberto; Gotor, Cecilia; Romero, Luis C.

2010-01-01

Cyanide is stoichiometrically produced as a coproduct of the ethylene biosynthesis pathway and is detoxified by β-cyanoalanine synthase enzymes. The molecular and phenotypical analysis of T-DNA insertion mutants of the mitochondrial β-cyanoalanine synthase CYS-C1 suggests that discrete accumulation of cyanide is not toxic for the plant and does not alter mitochondrial respiration rates but does act as a strong inhibitor of root hair development. The cys-c1 null allele is defective in root hair formation and accumulates cyanide in root tissues. The root hair defect is phenocopied in wild-type plants by the exogenous addition of cyanide to the growth medium and is reversed by the addition of hydroxocobalamin or by genetic complementation with the CYS-C1 gene. Hydroxocobalamin not only recovers the root phenotype of the mutant but also the formation of reactive oxygen species at the initial step of root hair tip growth. Transcriptional profiling of the cys-c1 mutant reveals that cyanide accumulation acts as a repressive signal for several genes encoding enzymes involved in cell wall rebuilding and the formation of the root hair tip as well as genes involved in ethylene signaling and metabolism. Our results demonstrate that mitochondrial β-cyanoalanine synthase activity is essential to maintain a low level of cyanide for proper root hair development. PMID:20935247

OsMOGS is required for N-glycan formation and auxin-mediated root development in rice (Oryza sativa L.)

PubMed Central

Zhang, SaiNa; Lim, Jae-Min; Lee, Kyun Oh; Li, ChuanYou; Qian, Qian; Jiang, De An; Qi, YanHua

2014-01-01

SUMMARY N-glycosylation is a major modification of glycoproteins in eukaryotic cells. In Arabidopsis, great progress has been made in functional analysis of N-glycan production; however, there are few studies in monocotyledons. Here, we characterized a rice (Oryza sativa L.) osmogs mutant with shortened roots and isolated a gene coding a putative mannosyl-oligosaccharide glucosidase (OsMOGS), an ortholog of α-glucosidase I in Arabidopsis, which trims the terminal glucosyl residue of the oligosaccharide chain of nascent peptides in the endoplasmic reticulum (ER). OsMOGS is strongly expressed in rapidly cell-dividing tissues and OsMOGS protein is localized in the ER. Mutation of OsMOGS entirely blocked N-glycan maturation and inhibited high-mannose N-glycan formation. The osmogs mutant exhibited severe defects in root cell division and elongation, resulting in a short-root phenotype. In addition, osmogs plants had impaired root hair formation and elongation, and reduced root epidemic cell wall thickness due to decreased cellulose synthesis. Further analysis showed that auxin content and polar transport in osmogs roots were reduced due to incomplete N-glycosylation of the B subfamily of ATP-binding cassette transporter proteins (ABCBs). Our results demonstrate that involvement of OsMOGS in N-glycan formation is required for auxin-mediated root development in rice. PMID:24597623

Specific plant induced biofilm formation in Methylobacterium species

PubMed Central

Rossetto, Priscilla B.; Dourado, Manuella N.; Quecine, Maria C.; Andreote, Fernando D.; Araújo, Welington L.; Azevedo, João L.; Pizzirani-Kleiner, Aline A.

2011-01-01

Two endophytic strains of Methylobacterium spp. were used to evaluate biofilm formation on sugarcane roots and on inert wooden sticks. Results show that biofilm formation is variable and that plant surface and possibly root exudates have a role in Methylobacterium spp. host recognition, biofilm formation and successful colonization as endophytes. PMID:24031703

Sedimentology and taphonomy of the upper Karoo-equivalent Mpandi Formation in the Tuli Basin of Zimbabwe, with a new 40Ar/ 39Ar age for the Tuli basalts

NASA Astrophysics Data System (ADS)

Rogers, Raymond R.; Rogers, Kristina Curry; Munyikwa, Darlington; Terry, Rebecca C.; Singer, Bradley S.

2004-10-01

Karoo-equivalent rocks in the Tuli Basin of Zimbabwe are described, with a focus on the dinosaur-bearing Mpandi Formation, which correlates with the Elliot Formation (Late Triassic-Early Jurassic) in the main Karoo Basin. Isolated exposures of the Mpandi Formation along the banks of the Limpopo River consist of red silty claystones and siltstones that preserve root traces, small carbonate nodules, and hematite-coated prosauropod bones. These fine-grained facies accumulated on an ancient semi-arid floodplain. Widespread exposures of quartz-rich sandstone and siltstone representing the upper Mpandi Formation crop out on Sentinel Ranch. These strata preserve carbonate concretions and silicified root casts, and exhibit cross-bedding indicative of deposition via traction currents, presumably in stream channels. Prosauropod fossils are also preserved in the Sentinel Ranch exposures, with one particularly noteworthy site characterized by a nearly complete and articulated Massospondylus individual. An unconformity caps the Mpandi Formation in the study area, and this stratigraphically significant surface rests on a laterally-continuous zone of pervasive silicification interpreted as a silcrete. Morphologic, petrographic, and geochemical data indicate that the Mpandi silcrete formed by intensive leaching near the ground surface during prolonged hiatus. Chert clasts eroded from the silcrete are intercalated at the base of the overlying Samkoto Formation (equivalent to the Clarens Formation in the main Karoo Basin), which in turn is overlain by the Tuli basalts. These basalts, which are part of the Karoo Igneous Province, yield a new 40Ar/ 39Ar plateau age of 186.3 ± 1.2 Ma.

Root Cortical Aerenchyma Enhances Nitrogen Acquisition from Low-Nitrogen Soils in Maize1[W][OPEN

PubMed Central

Saengwilai, Patompong; Nord, Eric A.; Chimungu, Joseph G.; Brown, Kathleen M.; Lynch, Jonathan Paul

2014-01-01

Suboptimal nitrogen (N) availability is a primary constraint for crop production in developing nations, while in rich nations, intensive N fertilization carries substantial environmental and economic costs. Therefore, understanding root phenes that enhance N acquisition is of considerable importance. Structural-functional modeling predicts that root cortical aerenchyma (RCA) could improve N acquisition in maize (Zea mays). We evaluated the utility of RCA for N acquisition by physiological comparison of maize recombinant inbred lines contrasting in RCA grown under suboptimal and adequate N availability in greenhouse mesocosms and in the field in the United States and South Africa. N stress increased RCA formation by 200% in mesocosms and by 90% to 100% in the field. RCA formation substantially reduced root respiration and root N content. Under low-N conditions, RCA formation increased rooting depth by 15% to 31%, increased leaf N content by 28% to 81%, increased leaf chlorophyll content by 22%, increased leaf CO2 assimilation by 22%, increased vegetative biomass by 31% to 66%, and increased grain yield by 58%. Our results are consistent with the hypothesis that RCA improves plant growth under N-limiting conditions by decreasing root metabolic costs, thereby enhancing soil exploration and N acquisition in deep soil strata. Although potential fitness tradeoffs of RCA formation are poorly understood, increased RCA formation appears be a promising breeding target for enhancing crop N acquisition. PMID:24891611

Indole-3-butyric acid induces lateral root formation via peroxisome-derived indole-3-acetic acid and nitric oxide.

PubMed

Schlicht, Markus; Ludwig-Müller, Jutta; Burbach, Christian; Volkmann, Dieter; Baluska, Frantisek

2013-10-01

Controlled plant growth requires regulation through a variety of signaling molecules, including steroids, peptides, radicals of oxygen and nitrogen, as well as the 'classical' phytohormone groups. Auxin is critical for the control of plant growth and also orchestrates many developmental processes, such as the formation of new roots. It modulates root architecture both slowly, through actions at the transcriptional level and, more rapidly, by mechanisms targeting primarily plasma membrane sensory systems and intracellular signaling pathways. The latter reactions use several second messengers, including Ca(2+) , nitric oxide (NO) and reactive oxygen species (ROS). Here, we investigated the different roles of two auxins, the major auxin indole-3-acetic acid (IAA) and another endogenous auxin indole-3-butyric acid (IBA), in the lateral root formation process of Arabidopsis and maize. This was mainly analyzed by different types of fluorescence microscopy and inhibitors of NO production. This study revealed that peroxisomal IBA to IAA conversion is followed by peroxisomal NO, which is important for IBA-induced lateral root formation. We conclude that peroxisomal NO emerges as a new player in auxin-induced root organogenesis. In particular, the spatially and temporally coordinated release of NO and IAA from peroxisomes is behind the strong promotion of lateral root formation via IBA. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Regulation of root morphogenesis in arbuscular mycorrhizae: what role do fungal exudates, phosphate, sugars and hormones play in lateral root formation?

PubMed Central

Fusconi, Anna

2014-01-01

Background Arbuscular mycorrhizae (AMs) form a widespread root–fungus symbiosis that improves plant phosphate (Pi) acquisition and modifies the physiology and development of host plants. Increased branching is recognized as a general feature of AM roots, and has been interpreted as a means of increasing suitable sites for colonization. Fungal exudates, which are involved in the dialogue between AM fungi and their host during the pre-colonization phase, play a well-documented role in lateral root (LR) formation. In addition, the increased Pi content of AM plants, in relation to Pi-starved controls, as well as changes in the delivery of carbohydrates to the roots and modulation of phytohormone concentration, transport and sensitivity, are probably involved in increasing root system branching. Scope This review discusses the possible causes of increased branching in AM plants. The differential root responses to Pi, sugars and hormones of potential AM host species are also highlighted and discussed in comparison with those of the non-host Arabidopsis thaliana. Conclusions Fungal exudates are probably the main compounds regulating AM root morphogenesis during the first colonization steps, while a complex network of interactions governs root development in established AMs. Colonization and high Pi act synergistically to increase root branching, and sugar transport towards the arbusculated cells may contribute to LR formation. In addition, AM colonization and high Pi generally increase auxin and cytokinin and decrease ethylene and strigolactone levels. With the exception of cytokinins, which seem to regulate mainly the root:shoot biomass ratio, these hormones play a leading role in governing root morphogenesis, with strigolactones and ethylene blocking LR formation in the non-colonized, Pi-starved plants, and auxin inducing them in colonized plants, or in plants grown under high Pi conditions. PMID:24227446

Root induced changes of effective 1D hydraulic properties in a soil column.

PubMed

Scholl, P; Leitner, D; Kammerer, G; Loiskandl, W; Kaul, H-P; Bodner, G

Roots are essential drivers of soil structure and pore formation. This study aimed at quantifying root induced changes of the pore size distribution (PSD). The focus was on the extent of clogging vs. formation of pores during active root growth. Parameters of Kosugi's lognormal PSD model were determined by inverse estimation in a column experiment with two cover crops (mustard, rye) and an unplanted control. Pore dynamics were described using a convection-dispersion like pore evolution model. Rooted treatments showed a wider range of pore radii with increasing volumes of large macropores >500 μm and micropores <2.5 μm, while fine macropores, mesopores and larger micropores decreased. The non-rooted control showed narrowing of the PSD and reduced porosity over all radius classes. The pore evolution model accurately described root induced changes, while structure degradation in the non-rooted control was not captured properly. Our study demonstrated significant short term root effects with heterogenization of the pore system as dominant process of root induced structure formation. Pore clogging is suggested as a partial cause for reduced pore volume. The important change in micro- and large macropores however indicates that multiple mechanic and biochemical processes are involved in root-pore interactions.

In vitro Cultured Primary Roots Derived from Stem Segments of Cassava (Manihot esculenta) Can Behave Like Storage Organs

PubMed Central

Medina, Ricardo D.; Faloci, Mirta M.; Gonzalez, Ana M.; Mroginski, Luis A.

2007-01-01

Background and Aims Cassava (Manihot esculenta) has three adventitious root types: primary and secondary fibrous roots, and storage roots. Different adventitious root types can also regenerate from in vitro cultured segments. The aim of this study was to investigate aspects of in vitro production of storage roots. Methods Morphological and anatomical analyses were performed to identify and differentiate each root type. Twenty-nine clones were assayed to determine the effect of genotype on the capacity to form storage roots in vitro. The effects of cytokinins and auxins on the formation of storage roots in vitro were also examined. Key Results Primary roots formed in vitro and in vivo had similar tissue kinds; however, storage roots formed in vitro exhibited physiological specialization for storing starch. The only consistent diagnostic feature between secondary fibrous and storage roots was their functional differentiation. Anatomical analysis of the storage roots formed in vitro showed that radial expansion as a consequence of massive proliferation and enlargement of parenchymatous cells occurred in the middle cortex, but not from cambial activity as in roots formed in vivo. Cortical expansion could be related to dilatation growth favoured by hormone treatments. Starch deposition of storage roots formed in vitro was confined to cortical tissue and occurred earlier than in storage roots formed in vivo. Auxin and cytokinin supplementation were absolutely required for in vitro storage root regeneration; these roots were not able to develop secondary growth, but formed a tissue competent for starch storing. MS medium with 5 % sucrose plus 0·54 μm 1-naphthaleneacetic acid and 0·44 μm 6-benzylaminopurine was one of the most effective in stimulating the storage root formation. Genotypes differed significantly in their capacity to produce storage roots in vitro. Storage root formation was considerably affected by the segment's primary position and strongly influenced by hormone treatments. Conclusions The storage root formation system reported here is a first approach to develop a tuberization model, and additional efforts are required to improve it. Although it was not possible to achieve root secondary growth, after this work it will be feasible to advance in some aspects of in vitro cassava tuberization. PMID:17267513

Ethylene-dependent aerenchyma formation in adventitious roots is regulated differently in rice and maize.

PubMed

Yamauchi, Takaki; Tanaka, Akihiro; Mori, Hitoshi; Takamure, Itsuro; Kato, Kiyoaki; Nakazono, Mikio

2016-10-01

In roots of gramineous plants, lysigenous aerenchyma is created by the death and lysis of cortical cells. Rice (Oryza sativa) constitutively forms aerenchyma under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. However, maize (Zea mays) develops aerenchyma only under oxygen-deficient conditions. Ethylene is involved in lysigenous aerenchyma formation. Here, we investigated how ethylene-dependent aerenchyma formation is differently regulated between rice and maize. For this purpose, in rice, we used the reduced culm number1 (rcn1) mutant, in which ethylene biosynthesis is suppressed. Ethylene is converted from 1-aminocyclopropane-1-carboxylic acid (ACC) by the action of ACC oxidase (ACO). We found that OsACO5 was highly expressed in the wild type, but not in rcn1, under aerobic conditions, suggesting that OsACO5 contributes to aerenchyma formation in aerated rice roots. By contrast, the ACO genes in maize roots were weakly expressed under aerobic conditions, and thus ACC treatment did not effectively induce ethylene production or aerenchyma formation, unlike in rice. Aerenchyma formation in rice roots after the initiation of oxygen-deficient conditions was faster and greater than that in maize. These results suggest that the difference in aerenchyma formation in rice and maize is due to their different mechanisms for regulating ethylene biosynthesis. © 2016 John Wiley & Sons Ltd.

Dynamics of air gap formation around roots with changing soil water content.

NASA Astrophysics Data System (ADS)

Vetterlein, D.; Carminati, A.; Weller, U.; Oswald, S.; Vogel, H.-J.

2009-04-01

Most models regarding uptake of water and nutrients from soil assume intimate contact between roots and soil. However, it is known for a long time that roots may shrink under drought conditions. Due to the opaque nature of soil this process could not be observed in situ until recently. Combining tomography of the entire sample (field of view of 16 x 16 cm, pixel side 0.32 mm) with local tomography of the soil region around roots (field of view of 5 x 5 cm, pixel side 0.09 mm), the high spatial resolution required to image root shrinkage and formation of air-filled gaps around roots could be achieved. Applying this technique and combining it with microtensiometer measurements, measurements of plant gas exchange and microscopic assessment of root anatomy, a more detailed study was conducted to elucidate at which soil matric potential roots start to shrink in a sandy soil and which are the consequences for plant water relations. For Lupinus albus grown in a sandy soil tomography of the entire root system and of the interface between taproot and soil was conducted from day 11 to day 31 covering two drying cycles. Soil matric potential decreased from -36 hPa at day 11 after planting to -72, -251, -429 hPa, on day 17, 19, 20 after planting. On day 20 an air gap started to occur around the tap root and extended further on day 21 with matric potential below -429 hPa (equivalent to 5 v/v % soil moisture). From day 11 to day 21 stomatal conductivity decreased from 467 to 84 mmol m-2 s-1, likewise transpiration rate decreased and plants showed strong wilting symptoms on day 21. Plants were watered by capillary rise on day 21 and recovered completely within a day with stomatal conductivity increasing to 647 mmol m-2 s-1. During a second drying cycle, which was shorter as plants continuously increased in size, air gap formed again at the same matric potential. Plant stomatal conductance and transpiration decreased in a similar fashion with decreasing matric potential and appearance of air gap as during the first cycle. Microscopic assessment of the tap root at day 31 showed that secondary thickening of the taproot occurred all along the region of interest observed during X-ray tomography. A large part of the cross sections consists of lignified tissue; no root hairs could be observed along the tap root. Gaps are expected to reduce water transfers between soil and roots. Opening and closing of gaps may help plants to prevent water loss when the soil dries, and to restore the soil-root continuity when water becomes available.

Demonstration of osmotically dependent promotion of aerenchyma formation at different levels in the primary roots of rice using a ‘sandwich’ method and X-ray computed tomography

PubMed Central

Karahara, Ichirou; Umemura, Konomi; Soga, Yuumi; Akai, Yuki; Bando, Tadafumi; Ito, Yuko; Tamaoki, Daisuke; Uesugi, Kentaro; Abe, Jun; Yamauchi, Daisuke; Mineyuki, Yoshinobu

2012-01-01

Background and Aims The effect of environmental factors on the regulation of aerenchyma formation in rice roots has been discussed for a long time, because aerenchyma is constitutively formed under aerated conditions. To elucidate this problem, a unique method has been developed that enables sensitive detection of differences in the development of aerenchyma under two different environmental conditions. The method is tested to determine whether aerenchyma development in rice roots is affected by osmotic stress. Methods To examine aerenchyma formation both with and without mannitol treatment in the same root, germinating rice (Oryza sativa) caryopses were sandwiched between two agar slabs, one of which contained 270 mm of mannitol. The roots were grown touching both slabs and were thereby exposed unilaterally to osmotic stress. As a non-invasive approach, refraction contrast X-ray computed tomography (CT) using a third-generation synchrotron facility, SPring-8 (Super photon ring 8 GeV, Japan Synchrotron Radiation Research Institute), was used to visualize the three-dimensional (3-D) intact structure of aerenchyma and its formation in situ in rice roots. The effects of unilateral mannitol treatment on the development of aerenchyma were quantitatively examined using conventional light microscopy. Key Results Structural continuity of aerenchyma was clearly visualized in 3-D in the primary root of rice and in situ using X-ray CT. Light microscopy and X-ray CT showed that the development of aerenchyma was promoted on the mannitol-treated side of the root. Detailed light microscopic analysis of cross-sections cut along the root axis from the tip to the basal region demonstrated that aerenchyma developed significantly closer to the root tip on the mannitol-treated side of the root. Conclusions Continuity of the aerenchyma along the rice root axis was morphologically demonstrated using X-ray CT. By using this ‘sandwich’ method it was shown that mannitol promoted aerenchyma formation in the primary roots of rice. PMID:22499856

Arabidopsis ROP-interactive CRIB motif-containing protein 1 (RIC1) positively regulates auxin signalling and negatively regulates abscisic acid (ABA) signalling during root development.

PubMed

Choi, Yunjung; Lee, Yuree; Kim, Soo Young; Lee, Youngsook; Hwang, Jae-Ung

2013-05-01

Auxin and abscisic acid (ABA) modulate numerous aspects of plant development together, mostly in opposite directions, suggesting that extensive crosstalk occurs between the signalling pathways of the two hormones. However, little is known about the nature of this crosstalk. We demonstrate that ROP-interactive CRIB motif-containing protein 1 (RIC1) is involved in the interaction between auxin- and ABA-regulated root growth and lateral root formation. RIC1 expression is highly induced by both hormones, and expressed in the roots of young seedlings. Whereas auxin-responsive gene induction and the effect of auxin on root growth and lateral root formation were suppressed in the ric1 knockout, ABA-responsive gene induction and the effect of ABA on seed germination, root growth and lateral root formation were potentiated. Thus, RIC1 positively regulates auxin responses, but negatively regulates ABA responses. Together, our results suggest that RIC1 is a component of the intricate signalling network that underlies auxin and ABA crosstalk. © 2012 Blackwell Publishing Ltd.

Transcriptional sequencing and analysis of major genes involved in the adventitious root formation of mango cotyledon segments.

PubMed

Li, Yun-He; Zhang, Hong-Na; Wu, Qing-Song; Muday, Gloria K

2017-06-01

A total of 74,745 unigenes were generated and 1975 DEGs were identified. Candidate genes that may be involved in the adventitious root formation of mango cotyledon segment were revealed. Adventitious root formation is a crucial step in plant vegetative propagation, but the molecular mechanism of adventitious root formation remains unclear. Adventitious roots formed only at the proximal cut surface (PCS) of mango cotyledon segments, whereas no roots were formed on the opposite, distal cut surface (DCS). To identify the transcript abundance changes linked to adventitious root development, RNA was isolated from PCS and DCS at 0, 4 and 7 days after culture, respectively. Illumina sequencing of libraries generated from these samples yielded 62.36 Gb high-quality reads that were assembled into 74,745 unigenes with an average sequence length of 807 base pairs, and 33,252 of the assembled unigenes at least had homologs in one of the public databases. Comparative analysis of these transcriptome databases revealed that between the different time points at PCS there were 1966 differentially expressed genes (DEGs), while there were only 51 DEGs for the PCS vs. DCS when time-matched samples were compared. Of these DEGs, 1636 were assigned to gene ontology (GO) classes, the majority of that was involved in cellular processes, metabolic processes and single-organism processes. Candidate genes that may be involved in the adventitious root formation of mango cotyledon segment are predicted to encode polar auxin transport carriers, auxin-regulated proteins, cell wall remodeling enzymes and ethylene-related proteins. In order to validate RNA-sequencing results, we further analyzed the expression profiles of 20 genes by quantitative real-time PCR. This study expands the transcriptome information for Mangifera indica and identifies candidate genes involved in adventitious root formation in cotyledon segments of mango.

High-efficiency induction of soybean hairy roots and propagation of the soybean cyst nematode.

PubMed

Cho, H J; Farrand, S K; Noel, G R; Widholm, J M

2000-01-01

Cotyledon explants of 10 soybean [Glycine max (L.) Merr.] cultivars were inoculated with Agrobacterium rhizogenes strain K599 with and without binary vectors pBI121 or pBINm-gfp5-ER possessing both neomycin phosphotransferase II (nptII) and beta-glucuronidase (gus) or nptII and green fluorescent protein (gfp) genes, respectively. Hairy roots were produced from the wounded surface of 54-95% of the cotyledon explants on MXB selective medium containing 200 microg ml(-1) kanamycin and 500 microg ml(-1) carbenicillin. Putative individual transformed hairy roots were identified by cucumopine analysis and were screened for transgene incorporation using polymerase chain reaction. All of the roots tested were found to be co-transformed with T-DNA from the Ri-plasmid and the transgene from the binary vectors. Southern blot analysis confirmed the presence of the 35S-gfp5 gene in the plant genomes. Transgene expression was also confirmed by histochemical GUS assay and Western blot analysis for the GFP. Attempts to induce shoot formation from the hairy roots failed. Infection of hairy roots of the soybean cyst nematode (Heterodera glycines Ichinohe)-susceptible cultivar, Williams 82, with eggs of H. glycines race 1, resulted in the development of mature cysts about 4-5 weeks after inoculation. Thus the soybean cyst nematode could complete its entire life cycle in transformed soybean hairy-root cultures expressing GFP. This system should be ideal for testing genes that might impart resistance to soybean cyst nematode.

Tracheophytes Contain Conserved Orthologs of a Basic Helix-Loop-Helix Transcription Factor That Modulate ROOT HAIR SPECIFIC Genes[OPEN

PubMed Central

Cho, Hyun-Min

2017-01-01

ROOT HAIR SPECIFIC (RHS) genes, which contain the root hair-specific cis-element (RHE) in their regulatory regions, function in root hair morphogenesis. Here, we demonstrate that an Arabidopsis thaliana basic helix-loop-helix transcription factor, ROOT HAIR DEFECTVE SIX-LIKE4 (RSL4), directly binds to the RHE in vitro and in vivo, upregulates RHS genes, and stimulates root hair formation in Arabidopsis. Orthologs of RSL4 from a eudicot (poplar [Populus trichocarpa]), a monocot (rice [Oryza sativa]), and a lycophyte (Selaginella moellendorffii) each restored root hair growth in the Arabidopsis rsl4 mutant. In addition, the rice and S. moellendorffii RSL4 orthologs bound to the RHE in in vitro and in vivo assays. The RSL4 orthologous genes contain RHEs in their promoter regions, and RSL4 was able to bind to its own RHEs in vivo and amplify its own expression. This process likely provides a positive feedback loop for sustainable root hair growth. When RSL4 and its orthologs were expressed in cells in non-root-hair positions, they induced ectopic root hair growth, indicating that these genes are sufficient to specify root hair formation. Our results suggest that RSL4 mediates root hair formation by regulating RHS genes and that this mechanism is conserved throughout the tracheophyte (vascular plant) lineage. PMID:28087829

Differences in root aeration, iron plaque formation and waterlogging tolerance in six mangroves along a continues tidal gradient.

PubMed

Cheng, Hao; Wang, You-Shao; Fei, Jiao; Jiang, Zhao-Yu; Ye, Zhi-Hong

2015-10-01

Mangrove is a special coastal forest along tropical and subtropical intertidal shores. However, how mangroves adapt to tidal flooding and the mechanisms involved in mangrove zonation are still poorly understood. In this study, a pot trial with different tide treatments was conducted to investigate the differences in root anatomy, porosity, radial oxygen loss, iron plaque formation and waterlogging tolerance among six mangroves along a continuous tidal gradient. The index of waterlogging tolerance illustrated that Sonneratia apetala possessed the highest index, followed by Aeguceras corniculatum/Kandelia, Rhizophora stylosa, Heritiera littorlis and Thespesia populnea. Waterlogging tolerances of the mangroves were found to be positively correlated with their root porosity, radial oxygen loss and iron plaque formation. Waterlogging-sensitive species such as landward semi-mangroves exhibited small root porosity and ROL, while waterlogging-tolerant species such as seaward pioneer and rhizophoraceous mangroves exhibited extensive porosity, ROL and iron plaque formation. Nevertheless, grater root porosity and iron plaque formation were detected in permanent waterlogged plants when compared to drained plants. In conclusion, The present study proposes a structural adaptive strategy to tidal flooding in mangroves, such that the mangroves with higher root porosity, ROL and iron plaque appeared to exhibit higher waterlogging tolerance and adaptability in anaerobic foreshores.

Control of Meloidogyne incognita Using Mixtures of Organic Acids

PubMed Central

Seo, Yunhee; Kim, Young Ho

2014-01-01

This study sought to control the root-knot nematode (RKN) Meloidogyne incognita using benign organo-chemicals. Second-stage juveniles (J2) of RKN were exposed to dilutions (1.0%, 0.5%, 0.2%, and 0.1%) of acetic acid (AA), lactic acid (LA), and their mixtures (MX). The nematode bodies were disrupted severely and moderately by vacuolations in 0.5% of MX and single organic acids, respectively, suggesting toxicity of MX may be higher than AA and LA. The mortality of J2 was 100% at all concentrations of AA and MX and only at 1.0% and 0.5% of LA, which lowered slightly at 0.2% and greatly at 0.1% of LA. This suggests the nematicidal activity of MX may be mostly derived from AA together with supplementary LA toxicity. MX was applied to chili pepper plants inoculated with about 1,000 J2, for which root-knot gall formations and plant growths were examined 4 weeks after inoculation. The root gall formation was completely inhibited by 0.5% MX and standard and double concentrations of fosthiazate; and inhibited 92.9% and 57.1% by 0.2% and 0.1% MX, respectively. Shoot height, shoot weight, and root weight were not significantly (P ≤ 0.05) different among all treatments and the untreated and non-inoculated controls. All of these results suggest that the mixture of the organic acids may have a potential to be developed as an eco-friendly nematode control agent that needs to be supported by the more nematode control experiments in fields. PMID:25506312

Degradation of mangrove tissues and implications for peat formation in Belizean island forests

USGS Publications Warehouse

Middleton, B.A.; McKee, K.L.

2001-01-01

1. Macrofaunal leaf consumption and degradation of leaves, woody twigs and roots were studied in mangrove island forests on a Belizean island. Factors influencing accumulation of organic matter deposited both above and below ground in this oligotrophic, autochothonous system were assessed. 2. Leaf degradation rates of Rhizophora mangle (red mangrove), Avicennia germinans (black mangrove) and Laguncularia racemosa (white mangrove) measured in mesh bags, were much faster in the lower than the upper intertidal zone. Mass loss was most rapid in A. germinans but zonal effects were much larger than species differences. 3. Exposure to invertebrates such as crabs and amphipods tripled overall rates of leaf litter breakdown. In the lower intertidal, crabs completely consumed some unbagged leaves within 23 days. Crabs also had an effect on some upper intertidal sites, where degradation of leaves placed in artificial burrows was 2.4 times faster than when placed on the soil surface. 4. In contrast to leaves (27??5% remaining after 230 days), roots and woody twigs were highly refractory (40??2% and 51??6% remaining after 584 and 540 days, respectively). Root degradation did not vary by soil depth, zone or species. Twigs of R. mangle and A. germinans degraded faster on the ground than in the canopy, whereas those of L. racemosa were highly resistant to decay regardless of position. 5. Peat formation at Twin Cays has occurred primarily through deposition and slow turnover of mangrove roots, rather than above-ground tissues that are either less abundant (woody twigs) or more readily removed (leaves).

Multiple essential MT1-MMP functions in tooth root formation, dentinogenesis, and tooth eruption

PubMed Central

Wimer, H.F.; Yamada, S.S.; Yang, T.; Holmbeck, K.; Foster, B.L.

2016-01-01

Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a transmembrane zinc-endopeptidase that breaks down extracellular matrix components, including several collagens, during tissue development and physiological remodeling. MT1-MMP-deficient mice (MT1-MMP−/−) feature severe defects in connective tissues, such as impaired growth, osteopenia, fibrosis, and conspicuous loss of molar tooth eruption and root formation. In order to define the functions of MT1-MMP during root formation and tooth eruption, we analyzed the development of teeth and surrounding tissues in the absence of MT1-MMP. In situ hybridization showed that MT1-MMP was widely expressed in cells associated with teeth and surrounding connective tissues during development. Multiple defects in dentoalveolar tissues were associated with loss of MT1-MMP. Root formation was inhibited by defective structure and function of Hertwig's epithelial root sheath (HERS). However, no defect was found in creation of the eruption pathway, suggesting that tooth eruption was hampered by lack of alveolar bone modeling/remodeling coincident with reduced periodontal ligament (PDL) formation and integration with the alveolar bone. Additionally, we identified a significant defect in dentin formation and mineralization associated with the loss of MT1-MMP. To segregate these multiple defects and trace their cellular origin, conditional ablation of MT1-MMP was performed in epithelia and mesenchyme. Mice featuring selective loss of MT1-MMP activity in the epithelium were indistinguishable from wild type mice, and importantly, featured a normal HERS structure and molar eruption. In contrast, selective knock-out of MT1-MMP in Osterix-expressing mesenchymal cells, including osteoblasts and odontoblasts, recapitulated major defects from the global knock-out including altered HERS structure, short roots, defective dentin formation and mineralization, and reduced alveolar bone formation, although molars were able to erupt. These data indicate that MT1-MMP activity in the dental mesenchyme, and not in epithelial-derived HERS, is essential for proper tooth root formation and eruption. In summary, our studies point to an indispensable role for MT1-MMP-mediated matrix remodeling in tooth eruption through effects on bone formation, soft tissue remodeling and organization of the follicle/PDL region. PMID:26780723

Orthodontic Movement after Regenerative Endodontic Procedure: Case Report and Long-term Observations.

PubMed

Chaniotis, Antonis

2018-03-01

Although regenerative treatment approaches in teeth with incomplete root formation and pulp necrosis have become part of the suggested therapeutic endodontic spectrum, little is known about the effect of orthodontic movement in the tissue that has been regenerated. Furthermore, as the number of adults undergoing orthodontic treatment increases, there is an increasing need to investigate the changes that these tissues may undergo during orthodontic movement. Here we describe the alterations observed after the application of orthodontic forces in a case of an apically root-fractured necrotic immature root that had been managed with regenerative endodontic procedures in the past. A 9-year-old male patient was referred after suffering the third incidence of trauma in the anterior maxilla. Radiographic evaluation revealed a periapical rarefaction associated with an apically root-fractured immature central incisor. Clinical evaluation revealed a buccal abscess and grade 3 tooth mobility. Periodontal probing was within normal limits. The tooth was accessed and disinfected by using apical negative pressure irrigation of 6% NaOCl. Intracanal dentin conditioning was achieved by using 17% EDTA for 5 minutes. A blood clot was induced from the periapical area, and calcium silicate-based cement was placed in direct contact with the blood clot at the same visit. The composite resin restoration was accomplished in the same appointment. Recall radiographic examination after 24 months revealed healing of the periapical lesion and signs of continuous root development despite the apical root fracture. Clinical evaluation revealed normal tooth development, normal mobility, and a resolving buccal infection. The tooth was subjected to orthodontic treatment because of Class II division 1 malocclusion with an overjet of 11 mm. After completion of the orthodontic treatment, 5.5 years after the initial intervention, the radiographic image revealed marked remodeling of the periapical tissues and repair of the apical fractures, and the buccal infection had resolved completely. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Mechanical Failure of Fine Root Cortical Cells Initiates Plant Hydraulic Decline during Drought.

PubMed

Cuneo, Italo F; Knipfer, Thorsten; Brodersen, Craig R; McElrone, Andrew J

2016-11-01

Root systems perform the crucial task of absorbing water from the soil to meet the demands of a transpiring canopy. Roots are thought to operate like electrical fuses, which break when carrying an excessive load under conditions of drought stress. Yet the exact site and sequence of this dysfunction in roots remain elusive. Using in vivo x-ray computed microtomography, we found that drought-induced mechanical failure (i.e. lacunae formation) in fine root cortical cells is the initial and primary driver of reduced fine root hydraulic conductivity (Lp r ) under mild to moderate drought stress. Cortical lacunae started forming under mild drought stress (-0.6 MPa Ψ stem ), coincided with a dramatic reduction in Lp r , and preceded root shrinkage or significant xylem embolism. Only under increased drought stress was embolism formation observed in the root xylem, and it appeared first in the fine roots (50% loss of hydraulic conductivity [P 50 ] reached at -1.8 MPa) and then in older, coarse roots (P 50 = -3.5 MPa). These results suggest that cortical cells in fine roots function like hydraulic fuses that decouple plants from drying soil, thus preserving the hydraulic integrity of the plant's vascular system under early stages of drought stress. Cortical lacunae formation led to permanent structural damage of the root cortex and nonrecoverable Lp r , pointing to a role in fine root mortality and turnover under drought stress. © 2016 American Society of Plant Biologists. All Rights Reserved.

PLETHORA transcription factors orchestrate de novo organ patterning during Arabidopsis lateral root outgrowth

PubMed Central

Du, Yujuan

2017-01-01

Plant development is characterized by repeated initiation of meristems, regions of dividing cells that give rise to new organs. During lateral root (LR) formation, new LR meristems are specified to support the outgrowth of LRs along a new axis. The determination of the sequential events required to form this new growth axis has been hampered by redundant activities of key transcription factors. Here, we characterize the effects of three PLETHORA (PLT) transcription factors, PLT3, PLT5, and PLT7, during LR outgrowth. In plt3plt5plt7 triple mutants, the morphology of lateral root primordia (LRP), the auxin response gradient, and the expression of meristem/tissue identity markers are impaired from the “symmetry-breaking” periclinal cell divisions during the transition between stage I and stage II, wherein cells first acquire different identities in the proximodistal and radial axes. Particularly, PLT1, PLT2, and PLT4 genes that are typically expressed later than PLT3, PLT5, and PLT7 during LR outgrowth are not induced in the mutant primordia, rendering “PLT-null” LRP. Reintroduction of any PLT clade member in the mutant primordia completely restores layer identities at stage II and rescues mutant defects in meristem and tissue establishment. Therefore, all PLT genes can activate the formative cell divisions that lead to de novo meristem establishment and tissue patterning associated with a new growth axis. PMID:29078398

Permanent tooth mineralization in bonobos (Pan paniscus) and chimpanzees (P. troglodytes).

PubMed

Boughner, Julia C; Dean, M Christopher; Wilgenbusch, Chelsea S

2012-12-01

The timing of tooth mineralization in bonobos (Pan paniscus) is virtually uncharacterized. Analysis of these developmental features in bonobos and the possible differences with its sister species, the chimpanzee (P. troglodytes), is important to properly quantify the normal ranges of dental growth variation in closely related primate species. Understanding this variation among bonobo, chimpanzee and modern human dental development is necessary to better contextualize the life histories of extinct hominins. This study tests whether bonobos and chimpanzees are distinguished from each other by covariance among the relative timing and sequences of tooth crown initiation, mineralization, root extension, and completion. Using multivariate statistical analyses, we compared the relative timing of permanent tooth crypt formation, crown mineralization, and root extension between 34 P. paniscus and 80 P. troglodytes mandibles radiographed in lateral and occlusal views. Covariance among our 12 assigned dental scores failed to statistically distinguish between bonobos and chimpanzees. Rather than clustering by species, individuals clustered by age group (infant, younger or older juvenile, and adult). Dental scores covaried similarly between the incisors, as well as between both premolars. Conversely, covariance among dental scores distinguished the canine and each of the three molars not only from each other, but also from the rest of the anterior teeth. Our study showed no significant differences in the relative timing of permanent tooth crown and root formation between bonobos and chimpanzees. Copyright © 2012 Wiley Periodicals, Inc.

Transcription factors PRE3 and WOX11 are involved in the formation of new lateral roots from secondary growth taproot in A. thaliana.

PubMed

Baesso, B; Chiatante, D; Terzaghi, M; Zenga, D; Nieminen, K; Mahonen, A P; Siligato, R; Helariutta, Y; Scippa, G S; Montagnoli, A

2018-05-01

The spatial deployment of lateral roots determines the ability of a plant to interact with the surrounding environment for nutrition and anchorage. This paper shows that besides the pericycle, the vascular cambium becomes active in Arabidopsis thaliana taproot at a later stage of development and is also able to form new lateral roots. To demonstrate the above, we implemented a two-step approach in which the first step leads to development of a secondary structure in A. thaliana taproot, and the second applies a mechanical stress on the vascular cambium to initiate formation of a new lateral root primordium. GUS staining showed PRE3, DR5 and WOX11 signals in the cambial zone of the root during new lateral root formation. An advanced level of wood formation, characterized by the presence of medullar rays, was achieved. Preliminary investigations suggest the involvement of auxin and two transcription factors (PRE3/ATBS1/bHLH135/TMO7 and WOX11) in the transition of some vascular cambium initials from a role as producers of xylem/phloem mother cells to founder cells of a new lateral root primordium. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

The effect of cellulose overproduction on binding and biofilm formation on roots by Agrobacterium tumefaciens.

PubMed

Matthysse, Ann G; Marry, Mazz; Krall, Leonard; Kaye, Mitchell; Ramey, Bronwyn E; Fuqua, Clay; White, Alan R

2005-09-01

Agrobacterium tumefaciens growing in liquid attaches to the surface of tomato and Arabidopsis thaliana roots, forming a biofilm. The bacteria also colonize roots grown in sterile quartz sand. Attachment, root colonization, and biofilm formation all were markedly reduced in celA and chvB mutants, deficient in production of cellulose and cyclic beta-(1,2)-D-glucans, respectively. We have identified two genes (celG and cell) in which mutations result in the overproduction of cellulose as judged by chemical fractionation and methylation analysis. Wild-type and chvB mutant strains carrying a cDNA clone of a cellulose synthase gene from the marine urochordate Ciona savignyi also overproduced cellulose. The overproduction in a wild-type strain resulted in increased biofilm formation on roots, as evaluated by light microscopy, and levels of root colonization intermediate between those of cellulose-minus mutants and the wild type. Overproduction of cellulose by a nonattaching chvB mutant restored biofilm formation and bacterial attachment in microscopic and viable cell count assays and partially restored root colonization. Although attachment to plant surfaces was restored, overproduction of cellulose did not restore virulence in the chvB mutant strain, suggesting that simple bacterial binding to plant surfaces is not sufficient for pathogenesis.

Auxins differentially regulate root system architecture and cell cycle protein levels in maize seedlings.

PubMed

Martínez-de la Cruz, Enrique; García-Ramírez, Elpidio; Vázquez-Ramos, Jorge M; Reyes de la Cruz, Homero; López-Bucio, José

2015-03-15

Maize (Zea mays) root system architecture has a complex organization, with adventitious and lateral roots determining its overall absorptive capacity. To generate basic information about the earlier stages of root development, we compared the post-embryonic growth of maize seedlings germinated in water-embedded cotton beds with that of plants obtained from embryonic axes cultivated in liquid medium. In addition, the effect of four different auxins, namely indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and 2,4-dichlorophenoxyacetic acid (2,4-D) on root architecture and levels of the heat shock protein HSP101 and the cell cycle proteins CKS1, CYCA1 and CDKA1 were analyzed. Our data show that during the first days after germination, maize seedlings develop several root types with a simultaneous and/or continuous growth. The post-embryonic root development started with the formation of the primary root (PR) and seminal scutellar roots (SSR) and then continued with the formation of adventitious crown roots (CR), brace roots (BR) and lateral roots (LR). Auxins affected root architecture in a dose-response fashion; whereas NAA and IBA mostly stimulated crown root formation, 2,4-D showed a strong repressing effect on growth. The levels of HSP101, CKS1, CYCA1 and CDKA in root and leaf tissues were differentially affected by auxins and interestingly, HSP101 registered an auxin-inducible and root specific expression pattern. Taken together, our results show the timing of early branching patterns of maize and indicate that auxins regulate root development likely through modulation of the HSP101 and cell cycle proteins. Copyright © 2014 Elsevier GmbH. All rights reserved.

Localized application of soil organic matter shifts distribution of cluster roots of white lupin in the soil profile due to localized release of phosphorus

PubMed Central

Li, Hai-Gang; Shen, Jian-Bo; Zhang, Fu-Suo; Lambers, Hans

2010-01-01

Background and Aims Phosphorus (P) is a major factor controlling cluster-root formation. Cluster-root proliferation tends to concentrate in organic matter (OM)-rich surface-soil layers, but the nature of this response of cluster-root formation to OM is not clear. Cluster-root proliferation in response to localized application of OM was characterized in Lupinus albus (white lupin) grown in stratified soil columns to test if the stimulating effect of OM on cluster-root formation was due to (a) P release from breakdown of OM; (b) a decrease in soil density; or (c) effects of micro-organisms other than releasing P from OM. Methods Lupin plants were grown in three-layer stratified soil columns where P was applied at 0 or 330 mg P kg−1 to create a P-deficient or P-sufficient background, and OM, phytate mixed with OM, or perlite was applied to the top or middle layers with or without sterilization. Key Results Non-sterile OM stimulated cluster-root proliferation and root length, and this effect became greater when phytate was supplied in the presence of OM. Both sterile OM and perlite significantly decreased cluster-root formation in the localized layers. The OM position did not change the proportion of total cluster roots to total roots in dry biomass among no-P treatments, but more cluster roots were concentrated in the OM layers with a decreased proportion in other places. Conclusions Localized application of non-sterile OM or phytate plus OM stimulated cluster-root proliferation of L. albus in the localized layers. This effect is predominantly accounted for by P release from breakdown of OM or phytate, but not due to a change in soil density associated with OM. No evidence was found for effects of micro-organisms in OM other than those responsible for P release. PMID:20150198

Tooth-bone morphogenesis during postnatal stages of mouse first molar development

PubMed Central

Lungová, Vlasta; Radlanski, Ralf J; Tucker, Abigail S; Renz, Herbert; Míšek, Ivan; Matalová, Eva

2011-01-01

The first mouse molar (M1) is the most common model for odontogenesis, with research particularly focused on prenatal development. However, the functional dentition forms postnatally, when the histogenesis and morphogenesis of the tooth is completed, the roots form and the tooth physically anchors into the jaw. In this work, M1 was studied from birth to eruption, assessing morphogenesis, proliferation and apoptosis, and correlating these with remodeling of the surrounding bony tissue. The M1 completed crown formation between postnatal (P) days 0–2, and the development of the tooth root was initiated at P4. From P2 until P12, cell proliferation in the dental epithelium reduced and shifted downward to the apical region of the forming root. In contrast, proliferation was maintained or increased in the mesenchymal cells of the dental follicle. At later stages, before tooth eruption (P20), cell proliferation suddenly ceased. This withdrawal from the cell cycle correlated with tooth mineralization and mesenchymal differentiation. Apoptosis was observed during all stages of M1 postnatal morphogenesis, playing a role in the removal of cells such as osteoblasts in the mandibular region and working together with osteoclasts to remodel the bone around the developing tooth. At more advanced developmental stages, apoptotic cells and bodies accumulated in the cell layers above the tooth cusps, in the path of eruption. Three-dimensional reconstruction of the developing postnatal tooth and bone indicates that the alveolar crypts form by resorption underneath the primordia, whereas the ridges form by active bone growth between the teeth and roots to form a functional complex. PMID:21418206

Efficacy of ProTaper universal retreatment files in removing filling materials during root canal retreatment.

PubMed

Giuliani, Valentina; Cocchetti, Roberto; Pagavino, Gabriella

2008-11-01

The aim of this study was to evaluate the efficacy of the ProTaper Universal System rotary retreatment system and of Profile 0.06 and hand instruments (K-file) in the removal of root filling materials. Forty-two extracted single-rooted anterior teeth were selected. The root canals were enlarged with nickel-titanium (NiTi) rotary files, filled with gutta-percha and sealer, and randomly divided into 3 experimental groups. The filling materials were removed with solvent in conjunction with one of the following devices and techniques: the ProTaper Universal System for retreatment, ProFile 0.06, and hand instruments (K-file). The roots were longitudinally sectioned, and the image of the root surface was photographed. The images were captured in JPEG format; the areas of the remaining filling materials and the time required for removing the gutta-percha and sealer were calculated by using the nonparametric one-way Kruskal-Wallis test and Tukey-Kramer tests, respectively. The group that showed better results for removing filling materials was the ProTaper Universal System for retreatment files, whereas the group of ProFile rotary instruments yielded better root canal cleanliness than the hand instruments, even though there was no statistically significant difference. The ProTaper Universal System for retreatment and ProFile rotary instruments worked significantly faster than the K-file. The ProTaper Universal System for retreatment files left cleaner root canal walls than the K-file hand instruments and the ProFile Rotary instruments, although none of the devices used guaranteed complete removal of the filling materials. The rotary NiTi system proved to be faster than hand instruments in removing root filling materials.

Assessment of Marginal Adaptation and Sealing Ability of Root Canal Sealers: An in vitro Study.

PubMed

Remy, Vimal; Krishnan, Vineesh; Job, Tisson V; Ravisankar, Madhavankutty S; Raj, C V Renjith; John, Seena

2017-12-01

This study aims to compare the marginal adaptation and sealing ability [mineral trioxide aggregate (MTA)-Fillapex, AH Plus, Endofill sealers] of root canal sealers. In the present study, the inclusion criteria include 45 single-rooted extracted mandibular premolar teeth, with single canal and complete root formation. The sectioning of the samples was done at the cementoenamel junction using a low-speed diamond disc. Step-back technique was used to prepare root canals manually. The MTA-Fillapex, AH Plus, and Endofill sealers were the three experimental sealer groups to which 45 teeth were distributed. Under scanning electron microscope (SEM), marginal gap at sealer and root dentin interface were examined at coronal and apical halves of root canal. Among the three maximum marginal adaptations were seen with AH Plus sealer (4.10 ± 0.10) which is followed by Endofill sealer (1.44 ± 0.18) and MTA-Fillapex sealer (0.80 ± 0.22). Between the coronal and apical marginal adaptation, significant statistical difference (p = 0.001) was seen in AH Plus sealer. When a Mann-Whitney U-test was done on MTA-Fillapex sealer vs AH Plus sealer and AH Plus sealer vs Endofill sealer, there was a statistically significant difference (p < 0.05) found between the above two groups at coronal and apical third. The present study proves that AH Plus sealer has a better marginal adaptation when compared with other sealers used. For sealing space of crown wall and main cone in root canal treatment, sealers play an important role. The other advantages of sealers are that they are used to fill voids and irregularities in root channel, secondary, lateral channels, and space between applied gutta-percha cones and also act as tripper during filling.

An Auxin Transport Independent Pathway Is Involved in Phosphate Stress-Induced Root Architectural Alterations in Arabidopsis. Identification of BIG as a Mediator of Auxin in Pericycle Cell Activation1

PubMed Central

López-Bucio, José; Hernández-Abreu, Esmeralda; Sánchez-Calderón, Lenin; Pérez-Torres, Anahí; Rampey, Rebekah A.; Bartel, Bonnie; Herrera-Estrella, Luis

2005-01-01

Arabidopsis (Arabidopsis thaliana) plants display a number of root developmental responses to low phosphate availability, including primary root growth inhibition, greater formation of lateral roots, and increased root hair elongation. To gain insight into the regulatory mechanisms by which phosphorus (P) availability alters postembryonic root development, we performed a mutant screen to identify genetic determinants involved in the response to P deprivation. Three low phosphate-resistant root lines (lpr1-1 to lpr1-3) were isolated because of their reduced lateral root formation in low P conditions. Genetic and molecular analyses revealed that all lpr1 mutants were allelic to BIG, which is required for normal auxin transport in Arabidopsis. Detailed characterization of lateral root primordia (LRP) development in wild-type and lpr1 mutants revealed that BIG is required for pericycle cell activation to form LRP in both high (1 mm) and low (1 μm) P conditions, but not for the low P-induced alterations in primary root growth, lateral root emergence, and root hair elongation. Exogenously supplied auxin restored normal lateral root formation in lpr1 mutants in the two P treatments. Treatment of wild-type Arabidopsis seedlings with brefeldin A, a fungal metabolite that blocks auxin transport, phenocopies the root developmental alterations observed in lpr1 mutants in both high and low P conditions, suggesting that BIG participates in vesicular targeting of auxin transporters. Taken together, our results show that auxin transport and BIG function have fundamental roles in pericycle cell activation to form LRP and promote root hair elongation. The mechanism that activates root system architectural alterations in response to P deprivation, however, seems to be independent of auxin transport and BIG. PMID:15681664

In vitro root induction of faba bean (Vicia faba L.).

PubMed

Ismail, Roba M; Elazab, Heba E M; Hussein, Gihan M H; Metry, Emad A

2011-01-01

A major challenge for regeneration of faba bean (Vicia faba L.) plants is the difficulty of in vitro root induction. In the present study, in vitro rooting and its architecture have been studied. Adventitious root formation was successfully induced from regenerated faba bean shoots of four Egyptian cultivars, i.e., Giza 461, Giza 40, Giza 834 and Giza 716 on hormone free MS medium supplemented with 5 mg/l silver nitrate. Among the four cultivars, Giza 461 and Giza 40 were recorded as the highest root formation response (75 % and 65) followed by cultivars Giza716 and Giza843 (20%, and 10%). Anatomical study proved that the produced roots are initiated as the adventitious lateral root (LR) with tri-arch xylem strands as compared with the penta-arch of the primary roots of the intact faba bean seedling. The obtained results overcome the root induction problem in faba bean.

Cellular and molecular mechanisms of tooth root development

PubMed Central

Li, Jingyuan; Parada, Carolina

2017-01-01

ABSTRACT The tooth root is an integral, functionally important part of our dentition. The formation of a functional root depends on epithelial-mesenchymal interactions and integration of the root with the jaw bone, blood supply and nerve innervations. The root development process therefore offers an attractive model for investigating organogenesis. Understanding how roots develop and how they can be bioengineered is also of great interest in the field of regenerative medicine. Here, we discuss recent advances in understanding the cellular and molecular mechanisms underlying tooth root formation. We review the function of cellular structure and components such as Hertwig's epithelial root sheath, cranial neural crest cells and stem cells residing in developing and adult teeth. We also highlight how complex signaling networks together with multiple transcription factors mediate tissue-tissue interactions that guide root development. Finally, we discuss the possible role of stem cells in establishing the crown-to-root transition, and provide an overview of root malformations and diseases in humans. PMID:28143844

An Undergraduate Study of Two Transcription Factors that Promote Lateral Root Formation

ERIC Educational Resources Information Center

Bargmann, Bastiaan O. R.; Birnbaum, Kenneth D.; Brenner, Eric D.

2014-01-01

We present a lab that enables students to test the role of genes involved in the regulation of lateral roots growth in the model plant "Arabidopsis thaliana." Here, students design an experiment that follows the effects of the hormone auxin on the stimulation of genes involved in the formation of lateral root initials. These genes, known…

Formation of the unusual semivolatile Diterpene Rhizathalene by the Arabidopsis Class I Terpene Synthase TPS08 in the root stele is involved in defense against belowground herbivory

USDA-ARS?s Scientific Manuscript database

Secondary metabolites are major constituents of plant defense against herbivore attack. Relatively little is known about the cell type-specific formation and anti-herbivore activities of secondary compounds in roots despite the substantial impact of root herbivory on plant performance and fitness. ...

Comparative proteomics analysis of Bacillus amyloliquefaciens SQR9 revealed the key proteins involved in in situ root colonization.

PubMed

Qiu, Meihua; Xu, Zhihui; Li, Xingxing; Li, Qing; Zhang, Nan; Shen, Qirong; Zhang, Ruifu

2014-12-05

Bacillus Amyloliquefaciens SQR9 is a well-investigated plant growth-promoting rhizobacteria with strong root colonization capability. To identify the key proteins involved in in situ root colonization and biofilm formation, the proteomic profiles of planktonic and root colonized SQR9 cells were compared. A total of 755 proteins were identified, of which 78 and 95 proteins were significantly increased and deceased, respectively, when SQR9 was colonized on the root. The proteins that were closely affiliated with the root colonization belonged to the functional categories of biocontrol, detoxification, biofilm formation, cell motility and chemotaxis, transport, and degradation of plant polysaccharides. A two-component system protein ResE was increased 100-fold when compared to the planktonic status; impairment of the resE gene postponed the formation of cell biofilm and decreased the root colonization capability, which may be regulated through the spo0A-sinI-yqxM pathway. The SQR9 proteomic data provide valuable clues for screening key proteins in the plant-rhizobacteria interaction.

High miR156 Expression Is Required for Auxin-Induced Adventitious Root Formation via MxSPL26 Independent of PINs and ARFs in Malus xiaojinensis

PubMed Central

Xu, Xiaozhao; Li, Xu; Hu, Xingwang; Wu, Ting; Wang, Yi; Xu, Xuefeng; Zhang, Xinzhong; Han, Zhenhai

2017-01-01

Adventitious root formation is essential for the vegetative propagation of perennial woody plants. During the juvenile-to-adult phase change mediated by the microRNA156 (miR156), the adventitious rooting ability decreases dramatically in many species, including apple rootstocks. However, the mechanism underlying how miR156 affects adventitious root formation is unclear. In the present study, we showed that in the presence of the synthetic auxin indole-3-butyric acid (IBA), semi-lignified leafy cuttings from juvenile phase (Mx-J) and rejuvenated (Mx-R) Malus xiaojinensis trees exhibited significantly higher expression of miR156, PIN-FORMED1 (PIN1), PIN10, and rootless concerning crown and seminal roots-like (RTCS-like) genes, thus resulting in higher adventitious rooting ability than those from adult phase (Mx-A) trees. However, the expression of SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE26 (SPL26) and some auxin response factor (ARF) gene family members were substantially higher in Mx-A than in Mx-R cuttings. The expression of NbRTCS-like but not NbPINs and NbARFs varied with miR156 expression in tobacco (Nicotiana benthamiana) plants transformed with 35S:MdMIR156a6 or 35S:MIM156 constructs. Overexpressing the miR156-resistant MxrSPL genes in tobacco confirmed the involvement of MxSPL20, MxSPL21&22, and MxSPL26 in adventitious root formation. Together, high expression of miR156 was necessary for auxin-induced adventitious root formation via MxSPL26, but independent of MxPINs and MxARFs expression in M. xiaojinensis leafy cuttings. PMID:28674551

Inactivation of Tgfbr2 in Osterix-Cre expressing Dental Mesenchyme Disrupts Molar Root Formation

PubMed Central

Coricor, George; MacDougall, Mary; Serra, Rosa

2013-01-01

It has been difficult to examine the role of TGF-ß in post-natal tooth development due to perinatal lethality in many of the signaling deficient mouse models. To address the role of Tgfbr2 in postnatal tooth development, we generated a mouse in which Tgfbr2 was deleted in odontoblast-and bone-producing mesenchyme. Osx-Cre;Tgfbr2fl/fl mice were generated (Tgfbr2cko) and postnatal tooth development was compared in Tgfbr2cko and control littermates. X-ray and μCT analysis showed that in Tgfbr2cko mice radicular dentin matrix density was reduced in the molars. Molar shape was abnormal and molar eruption was delayed in the mutant mice. Most significantly, defects in root formation, including failure of the root to elongate, were observed by postnatal day 10. Immunostaining for Keratin-14 (K14) was used to delineate Hertwig's epithelial root sheath (HERS). The results showed a delay in elongation and disorganization of the HERS in Tgfbr2cko mice. In addition, the HERS was maintained and the break up into epithelial rests was attenuated suggesting that Tgfbr2 acts on dental mesenchyme to indirectly regulate the formation and maintenance of the HERS. Altered odontoblast organization and reduced Dspp expression indicated that odontoblast differentiation was disrupted in the mutant mice likely contributing to the defect in root formation. Nevertheless, expression of Nfic, a key mesenchymal regulator of root development, was similar in Tgfbr2cko mice and controls. The number of osteoclasts in the bone surrounding the tooth was reduced and osteoblast differentiation was disrupted likely contributing to both root and eruption defects. We conclude that Tgfbr2 in dental mesenchyme and bone is required for tooth development particularly root formation. PMID:23933490

Iron plaque formation and morphoanatomy of roots from species of restinga subjected to excess iron.

PubMed

Siqueira-Silva, Advanio Inácio; da Silva, Luzimar Campos; Azevedo, Aristéa Alves; Oliva, Marco Antonio

2012-04-01

The restingas, a sandy coastal plain ecosystem of Brazil, have received an additional amount of iron due to the activity of mining industries. The present study aims to characterize morphoanatomically and histochemically the iron plaque formation on roots of Ipomoea pes-caprae L. and Canavalia rosea DC, cultivated in hydroponic solution with and without excess iron. The iron plaque formation as well as changes in the external morphology of the lateral roots of both species were observed after the subjection to excess iron. Changes in the nutrient uptake, and in the organization and form of the pericycle and cortex cells were observed for both species. Scanning electron microscopy showed evident iron plaques on the whole surface of the root. The iron was histolocalized in all root tissues of both species. The species of restinga studied here formed iron plaque in their roots when exposed to excess of this element, which may compromise their development in environments polluted by particulated iron. Copyright © 2011 Elsevier Inc. All rights reserved.

Effects of glucose and ethylene on root hair initiation and elongation in lettuce (Lactuca sativa L.) seedlings.

PubMed

Harigaya, Wakana; Takahashi, Hidenori

2018-05-01

Root hair formation occurs in lettuce seedlings after transfer to an acidic medium (pH 4.0). This process requires cortical microtubule (CMT) randomization in root epidermal cells and the plant hormone ethylene. We investigated the interaction between ethylene and glucose, a new signaling molecule in plants, in lettuce root development, with an emphasis on root hair formation. Dark-grown seedlings were used to exclude the effect of photosynthetically produced glucose. In the dark, neither root hair formation nor the CMT randomization preceding it occurred, even after transfer to the acidic medium (pH 4.0). Adding 1-aminocyclopropane-1-carboxylic-acid (ACC) to the medium rescued the induction, while adding glucose did not. Although CMT randomization occurred when glucose was applied together with ACC, it was somewhat suppressed compared to that in ACC-treated seedlings. This was not due to a decrease in the speed of randomization, but due to lowering of the maximum degree of randomization. Despite the negative effect of glucose on ACC-induced CMT randomization, the density and length of ACC-induced root hairs increased when glucose was also added. The hair-cell length of the ACC-treated seedlings was comparable to that in the combined-treatment seedlings, indicating that the increase in hair density caused by glucose results from an increase in the root hair number. Furthermore, quantitative RT-PCR revealed that glucose suppressed ethylene signaling. These results suggest that glucose has a negative and positive effect on the earlier and later stages of root hair formation, respectively, and that the promotion of the initiation and elongation of root hairs by glucose may be mediated in an ethylene-independent manner.

Effects of light and growth regulators on adventitious bud formation in horseradish (Armoracia rusticana).

PubMed

Kamada, H; Tachikawa, Y; Saitou, T; Harada, H

1995-07-01

To clarify that the presence of Ri T-DNA genes are not prerequisite for the light-induced bud formation in horseradish (Armoracia rusticana) hairy roots, leaf and root segments of nontransformed horseradish plants were used as explants. Bud formation from nontransformed tissues was observed in hormone-free medium under 16 h daylight conditions, but not under continuous darkness. To investigate the effects of growth regulators on bud formation, leaf and root explants were treated with auxin (1-naphthaleneacetic acid; NAA) and / or cytokinin (6-benzyl-aminopurine; BA). The most effective treatment in the dark to stimulate bud formation was BA at 1 mg·1(-1). These results show that adventitious bud formation in horseradish can be induced by light and growth regulators, and especially cytokinin, may be involved in bud formation, irrespective of whether the tissues were transformed with Ri T-DNA.

Comparative Developmental Anatomy of the Root in Three Species of Cladopus (Podostemaceae)

PubMed Central

KOI, SATOSHI; KATO, MASAHIRO

2003-01-01

Root meristem structure and root branching in three species of Cladopus were investigated from developmental and anatomical perspectives. Cladopus fukiensis has a compressed bell‐shaped meristem at the apex of a compressed subcylindrical root, while C. javanicus and perhaps C. nymanii, with a ribbon‐like root, have a half lozenge‐shaped (⊂ as seen from above) meristem composed of an apical meristem of cubic cells and a marginal meristem of rectangular cells. The dorsiventrality of the meristem results in root dorsiventrality, and a marginal meristem contributes to the broadening of the root. Comparisons of meristem structure and root morphology suggest that the ribbon‐like root of, e.g. C. javanicus, evolved towards the foliose root of Hydrobryum, sister to the genus Cladopus, by loss of an indeterminate apical meristem. The lateral root of C. javanicus initiates within the meristem of a parent root. The dorsal dermal layer and inner cells of the lateral‐root meristem appear endogenously under the dermal layer of the parent root, while the ventral layer is derived exogenously from a ventral dermal layer continuous with the parent‐root meristem. This mosaic pattern of exogenous and endogenous root formation differs from the truly exogenous formation seen in Hydrobryum and Zeylanidium. The dorsiventral mosaic origin of the root meristem may account for root cap asymmetry. PMID:12770848

Micropropagation of ornamental Prunus spp. and GF305 peach, a Prunus viral indicator.

PubMed

Kalinina, Anna; Brown, Daniel C W

2007-07-01

A micropropagation approach was developed for nine ornamental Prunus species, P. americana, P. cistena, P. glandulosa, P. serrulata 'Kwanzan', P. laurocerasus, P. sargentii, P. tomentosa, P. triloba, P. virginiana 'Schubert', commercially important in North America, and GF305 peach, commonly used for Prunus virus indexing. The micropropagation cycle based on proliferation of vegetative tissues includes establishment of tissue culture through introduction of shoot meristems in vitro, shoot proliferation, root induction and plant acclimatization steps and can be completed in 5 months. A meristem sterilization protocol minimized bacterial and fungal contamination. Multiple shoot formation in ornamental Prunus was obtained through the use of 1 mg l(-1) 6-benzyladenine. For GF305 peach, alteration in the sugar composition, fructose instead of sucrose, and addition of 1 mg l(-1 )ferulic acid had a significant impact on the shoot proliferation rate and maintenance of long-term in vitro culture. Rooting and plant acclimatization conditions were improved using a two-step protocol with a 4-day root induction in indole-3-butiric acid (IBA)-containing media with consequent 3-week root elongation in IBA-free media. One-month incubation of rooted shoots in a vermiculite-based medium resulted in additional shoot and root growth and provided better acclimatization and plant recovery. The micropropagation approach can be used for maintenance of the clonal properties for Prunus spp. as well as a protocol to support meristem therapy against viral infection.

Tomato root growth, gravitropism, and lateral development: correlation with auxin transport

NASA Technical Reports Server (NTRS)

Muday, G. K.; Haworth, P.

1994-01-01

Tomato (Lycopersicon esculentum, Mill.) roots were analyzed during growth on agar plates. Growth of these roots was inhibited by the auxin transport inhibitors naphthylphthalamic acid (NPA) and semicarbazone derivative I (SCB-1). The effect of auxin transport inhibitors on root gravitropism was analyzed by measurement of the angle of gravitropic curvature after the roots were reoriented 90 degrees from the vertical. NPA and SCB-1 abolished both the response of these roots to gravity and the formation of lateral roots, with SCB-1 being the more effective at inhibition. Auxins also inhibited root growth. Both auxins tested has a slight effect on the gravity response, but this effect is probably indirect, since auxins reduced the growth rate. Auxins also stimulated lateral root growth at concentration where primary root growth was inhibited. When roots were treated with both IAA and NPA simultaneously, a cumulative inhibition of root growth was found. When both compounds were applied together, analysis of gravitropism and lateral root formation indicated that the dominant effect was exerted by auxin transport inhibitors. Together, these data suggest a model for the role of auxin transport in controlling both primary and lateral root growth.

Transcriptomic and anatomical complexity of primary, seminal, and crown roots highlight root type-specific functional diversity in maize (Zea mays L.)

PubMed Central

Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank

2016-01-01

Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. PMID:26628518

When stress and development go hand in hand: main hormonal controls of adventitious rooting in cuttings

PubMed Central

da Costa, Cibele T.; de Almeida, Márcia R.; Ruedell, Carolina M.; Schwambach, Joseli; Maraschin, Felipe S.; Fett-Neto, Arthur G.

2013-01-01

Adventitious rooting (AR) is a multifactorial response leading to new roots at the base of stem cuttings, and the establishment of a complete and autonomous plant. AR has two main phases: (a) induction, with a requirement for higher auxin concentration; (b) formation, inhibited by high auxin and in which anatomical changes take place. The first stages of this process in severed organs necessarily include wounding and water stress responses which may trigger hormonal changes that contribute to reprogram target cells that are competent to respond to rooting stimuli. At severance, the roles of jasmonate and abscisic acid are critical for wound response and perhaps sink strength establishment, although their negative roles on the cell cycle may inhibit root induction. Strigolactones may also inhibit AR. A reduced concentration of cytokinins in cuttings results from the separation of the root system, whose tips are a relevant source of these root induction inhibitors. The combined increased accumulation of basipetally transported auxins from the shoot apex at the cutting base is often sufficient for AR in easy-to-root species. The role of peroxidases and phenolic compounds in auxin catabolism may be critical at these early stages right after wounding. The events leading to AR strongly depend on mother plant nutritional status, both in terms of minerals and carbohydrates, as well as on sink establishment at cutting bases. Auxins play a central role in AR. Auxin transporters control auxin canalization to target cells. There, auxins act primarily through selective proteolysis and cell wall loosening, via their receptor proteins TIR1 (transport inhibitor response 1) and ABP1 (Auxin-Binding Protein 1). A complex microRNA circuitry is involved in the control of auxin response factors essential for gene expression in AR. After root establishment, new hormonal controls take place, with auxins being required at lower concentrations for root meristem maintenance and cytokinins needed for root tissue differentiation. PMID:23717317

When stress and development go hand in hand: main hormonal controls of adventitious rooting in cuttings.

PubMed

da Costa, Cibele T; de Almeida, Márcia R; Ruedell, Carolina M; Schwambach, Joseli; Maraschin, Felipe S; Fett-Neto, Arthur G

2013-01-01

Adventitious rooting (AR) is a multifactorial response leading to new roots at the base of stem cuttings, and the establishment of a complete and autonomous plant. AR has two main phases: (a) induction, with a requirement for higher auxin concentration; (b) formation, inhibited by high auxin and in which anatomical changes take place. The first stages of this process in severed organs necessarily include wounding and water stress responses which may trigger hormonal changes that contribute to reprogram target cells that are competent to respond to rooting stimuli. At severance, the roles of jasmonate and abscisic acid are critical for wound response and perhaps sink strength establishment, although their negative roles on the cell cycle may inhibit root induction. Strigolactones may also inhibit AR. A reduced concentration of cytokinins in cuttings results from the separation of the root system, whose tips are a relevant source of these root induction inhibitors. The combined increased accumulation of basipetally transported auxins from the shoot apex at the cutting base is often sufficient for AR in easy-to-root species. The role of peroxidases and phenolic compounds in auxin catabolism may be critical at these early stages right after wounding. The events leading to AR strongly depend on mother plant nutritional status, both in terms of minerals and carbohydrates, as well as on sink establishment at cutting bases. Auxins play a central role in AR. Auxin transporters control auxin canalization to target cells. There, auxins act primarily through selective proteolysis and cell wall loosening, via their receptor proteins TIR1 (transport inhibitor response 1) and ABP1 (Auxin-Binding Protein 1). A complex microRNA circuitry is involved in the control of auxin response factors essential for gene expression in AR. After root establishment, new hormonal controls take place, with auxins being required at lower concentrations for root meristem maintenance and cytokinins needed for root tissue differentiation.

Final Technical Report: Microbial Production of Isoprene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fall, Ray

2003-09-12

OAK B135 We have discovered that bacteria produce and emit the hydrocarbon isoprene (2-methyl-1,3-butadiene), and have suggested that if isoprene-producing enzymes and their genes can be harnessed, useful hydrocarbon-producing systems might be constructed. The main goal of the proposed work was to establish the biochemical mechanism and regulation of isoprene formation in the model bacterial system, Bacillus subtilis. In this 3-year project we (a) characterized the physiological regulation of isoprene formation in B. subtilis and its relationship to isoprene formation in plant chloroplasts; (b) analyzed genetic controls on isoprene formation in B. subtilis; and (c) developed models to explain themore » biochemical rationale for isoprene formation. We are also pursued (d) new methods for continuous measurement of isoprene release in bioreactors, and (e) determined the presence of isoprene-forming Bacillus on plant roots and used B. subtilis as a biocontrol agent for protection of plant roots from plant pathogenic bacteria. We have made significant advances in several areas. These include: (1) establishing the enzymatic basis of isoprene formation in B. subtilis, and demonstrating throughout growth in a bioreactor that isoprene synthase activity rises and falls with each of three peaks of isoprene release (i.e. it appears to be a regulated enzyme). (2) We have explored genetic aspects of isoprene formation, using gene disruption methods to greatly alter the patterns of isoprene formation in bioreactors. Analysis of these mutants and alteration of cellular levels of dimethylallyl diphosphate (DMAPP), the substrate for isoprene synthase, has led to the formulation of two models to explain why isoprene is formed: an isoprenoid overflow model and a signaling model. We have obtained compelling evidence that isoprene releases in bioreactors result from metabolic overflow. However, we have yet to determine the pattern of isoprene formation when these bacteria are grown in a more natural state (e.g. as biofilms on surfaces). (3) We successfully used on-line mass spectrometry methods to measure release of volatiles, including isoprene, from bioreactors during growth of B. subtilis. This methodology, still in its infancy, may provide a new means to assess physiological processes during industrial growth of Bacillus species, and use isoprene formation as a barometer of carbon flow in these bacteria. (4) We also addressed the question: is Bacillus isoprene formation analogous to chloroplast processes? This research was initiated because of the continuing interest in the puzzle of isoprene formation in leaf chloroplasts. In pursuit of linkages between bacterial and plant isoprene formation, we used our DMAPP assay to demonstrate that leaves of the isoprene-emitter (cottonwood) show a diurnal cycle, peaking at mid-day in parallel with isoprene release. Thus it appears that in two different biological systems isoprene formation is highly regulated, and linked to isoprenoid carbon availability. (5) We developed a new method to detect Bacillus species in plant root samples, and demonstrated that plant roots are a rich source of biofilm-forming B. subtilis. Furthermore, using cultured Arabidopsis roots as a test system, we were able to demonstrate the formation of stable, viable Bacillus biofilms on the roots. Such roots were protected from killing by a root pathogenic Pseudomonas syringae strain. We have now formulated a mechanism to explain how such biocontrol by B. subtilis occurs, and future work will explore the role of isoprene in signaling between different rhizobacteria and plant roots.« less

Tooth Eruption without Roots

PubMed Central

2013-01-01

Root development and tooth eruption are very important topics in dentistry. However, they remain among the less-studied and -understood subjects. Root development accompanies rapid tooth eruption, but roots are required for the movement of teeth into the oral cavity. It has been shown that the dental follicle and bone remodeling are essential for tooth eruption. So far, only limited genes have been associated with root formation and tooth eruption. This may be due to the difficulties in studying late stages of tooth development and tooth movement and the lack of good model systems. Transgenic mice with eruption problems and short or no roots can be used as a powerful model for further deciphering of the cellular, molecular, and genetic mechanisms underlying root formation and tooth eruption. Better understanding of these processes can provide hints on delivering more efficient dental therapies in the future. PMID:23345536

Alkaloids in plants and root cultures of Atropa belladonna overexpressing putrescine N-methyltransferase.

PubMed

Rothe, Grit; Hachiya, Akira; Yamada, Yasuyuki; Hashimoto, Takashi; Dräger, Birgit

2003-09-01

Putrescine N-methyltransferase (PMT) is the first alkaloid-specific enzyme for nicotine and tropane alkaloid formation. The pmt gene from Nicotiana tabacum was fused to the CaMV 35S promoter and integrated into the Atropa belladonna genome. Transgenic plants and derived root cultures were analysed for gene expression and for levels of alkaloids and their precursors. Scopolamine, hyoscyamine, tropine, pseudotropine, tropinone, and calystegines were found unaltered or somewhat decreased in pmt-overexpressing lines compared to controls. When root cultures were treated with 5% sucrose, calystegine levels were elevated in control roots, but were not affected in pmt-overexpressing roots. 1 microM auxin reduced calystegine levels in control roots, while in pmt-overexpressing roots all alkaloids remained unaltered. Expression level of pmt alone is apparently not limiting for tropane alkaloid formation in A. belladonna.

Combined periodontic-orthodonticendodontic interdisciplinary approach in the treatment of periodontally compromised tooth.

PubMed

Deepa, D; Mehta, D S; Puri, Viren K; Shetty, Sadashiva

2010-04-01

Orthodontic treatment in adult patients is one of the most frequently encountered components involving multidisciplinary approaches. In the present report, a 28-year-old male patient was treated for localized chronic periodontitis with pocket formation, mobility, pathologic migration and malalignment of maxillary left lateral incisor tooth #22. The periodontal therapy included motivation, education and oral-hygiene instructions (O.H.I.), scaling and root planing and periodontal flap surgery. Subsequently on resolution of periodontal inflammation, orthodontic therapy was carried out using the orthodontic aligner for a period of 6 months. Post-treatment (3 years) results showed complete resolution of infrabony pocket with significant bone fill, reduced tooth mobility and complete alignment of the affected maxillary left lateral incisor, thus restoring the esthetics and function.

Interactions between light intensity and phosphorus nutrition affect the phosphate-mining capacity of white lupin (Lupinus albus L.)

PubMed Central

Cheng, Lingyun; Tang, Xiaoyan; Vance, Carroll P.; White, Philip J.; Zhang, Fusuo; Shen, Jianbo

2014-01-01

Light intensity affects photosynthetic carbon (C) fixation and the supply of carbon to roots. To evaluate interactions between carbon supply and phosphorus (P) supply, effects of light intensity on sucrose accumulation, root growth, cluster root formation, carboxylate exudation, and P uptake capacity were studied in white lupin (Lupinus albus L.) grown hydroponically with either 200 µmol m–2 s–1 or 600 µmol m–2 s–1 light and a sufficient (50 µM P) or deficient (1 µM P) P supply. Plant biomass and root:shoot ratio increased with increasing light intensity, particularly when plants were supplied with sufficient P. Both low P supply and increasing light intensity increased the production of cluster roots and citrate exudation. Transcripts of a phosphoenol pyruvate carboxylase gene (LaPEPC3) in cluster roots (which is related to the exudation of citrate), transcripts of a phosphate transporter gene (LaPT1), and P uptake all increased with increasing light intensity, under both P-sufficient and P-deficient conditions. Across all four experimental treatments, increased cluster root formation and carboxylate exudation were associated with lower P concentration in the shoot and greater sucrose concentration in the roots. It is suggested that C in excess of shoot growth capabilities is translocated to the roots as sucrose, which serves as both a nutritional signal and a C-substrate for carboxylate exudation and cluster root formation. PMID:24723402

Introduction to Blueweb: A Decentralized Scatternet Formation Algorithm for Bluetooth Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Yu, Chih-Min; Huang, Chia-Chi

In this letter, a decentralized scatternet formation algorithm called Bluelayer is proposed. First, Bluelayer uses a designated root to construct a tree-shaped subnet and propagates an integer variable k1 called counter limit as well as a constant k in its downstream direction to determine new roots. Then each new root asks its upstream master to start a return connection procedure to convert the tree-shaped subnet into a web-shaped subnet for its immediate upstream root. At the same time, each new root repeats the same procedure as the root to build its own subnet until the whole scatternet is formed. Simulation results show that Bluelayer achieves good network scalability and generates an efficient scatternet configuration for various sizes of Bluetooth ad hoc network.

Form matters: morphological aspects of lateral root development

PubMed Central

Szymanowska-Pułka, Joanna

2013-01-01

Background The crucial role of roots in plant nutrition, and consequently in plant productivity, is a strong motivation to study the growth and functioning of various aspects of the root system. Numerous studies on lateral roots, as a major determinant of the root system architecture, mostly focus on the physiological and molecular bases of developmental processes. Unfortunately, little attention is paid either to the morphological changes accompanying the formation of a lateral root or to morphological defects occurring in lateral root primordia. The latter are observed in some mutants and occasionally in wild-type plants, but may also result from application of external factors. Scope and Conclusions In this review various morphological aspects of lateral branching in roots are analysed. Morphological events occurring during the formation of a typical lateral root are described. This process involves dramatic changes in the geometry of the developing organ that at early stages are associated with oblique cell divisions, leading to breaking of the symmetry of the cell pattern. Several types of defects in the morphology of primordia are indicated and described. Computer simulations show that some of these defects may result from an unstable field of growth rates. Significant changes in both primary and lateral root morphology may also be a consequence of various mutations, some of which are auxin-related. Examples reported in the literature are considered. Finally, lateral root formation is discussed in terms of mechanics. In this approach the primordium is considered as a physical object undergoing deformation and is characterized by specific mechanical properties. PMID:24190952

Microarray Analyses of Gene Expression during Adventitious Root Development in Pinus contorta1[w

PubMed Central

Brinker, Monika; van Zyl, Leonel; Liu, Wenbin; Craig, Deborah; Sederoff, Ronald R.; Clapham, David H.; von Arnold, Sara

2004-01-01

In order to investigate the gene expression pattern during adventitious root development, RNA of Pinus contorta hypocotyls, pulse-treated with the auxin indole-3-butyric acid and harvested at distinct developmental time points of root development, was hybridized to microarrays containing 2,178 cDNAs from Pinus taeda. Over the period of observation of root development, the transcript levels of 220 genes changed significantly. During the root initiation phase, genes involved in cell replication and cell wall weakening and a transcript encoding a PINHEAD/ZWILLE-like protein were up-regulated, while genes related to auxin transport, photosynthesis, and cell wall synthesis were down-regulated. In addition, there were changes in transcript abundance of genes related to water stress. During the root meristem formation phase the transcript abundances of genes involved in auxin transport, auxin responsive transcription, and cell wall synthesis, and of a gene encoding a B-box zinc finger-like protein, increased, while those encoding proteins involved in cell wall weakening decreased. Changes of transcript abundance of genes related to water stress during the root meristem formation and root formation phase indicate that the plant roots had become functional in water transport. Simultaneously, genes involved in auxin transport were up-regulated, while genes related to cell wall modification were down-regulated. Finally, during the root elongation phase down-regulation of transcripts encoding proteins involved in cell replication and stress occurred. Based on the observed changes in transcript abundances, we suggest hypotheses about the relative importance of various physiological processes during the auxin-induced development of roots in P. contorta. PMID:15247392

The Tomato (Solanum Lycopersicum cv. Micro-Tom) Natural Genetic Variation Rg1 and the DELLA Mutant Procera Control the Competence Necessary to Form Adventitious Roots and Shoots

PubMed Central

Peres, Lázaro Eustáquio Pereira

2012-01-01

Despite the wide use of plant regeneration for biotechnological purposes, the signals that allow cells to become competent to assume different fates remain largely unknown. Here, it is demonstrated that the Regeneration1 (Rg1) allele, a natural genetic variation from the tomato wild relative Solanum peruvianum, increases the capacity to form both roots and shoots in vitro; and that the gibberellin constitutive mutant procera (pro) presented the opposite phenotype, reducing organogenesis on either root-inducing medium (RIM) or shoot-inducing medium (SIM). Mutants showing alterations in the formation of specific organs in vitro were the auxin low-sensitivity diageotropica (dgt), the lateral suppresser (ls), and the KNOX-overexpressing Mouse ears (Me). dgt failed to form roots on RIM, Me increased shoot formation on SIM, and the high capacity for in vitro shoot formation of ls contrasted with its recalcitrance to form axillary meristems. Interestingly, Rg1 rescued the in vitro organ formation capacity in proRg1 and dgtRg1 double mutants and the ex vitro low lateral shoot formation in pro and ls. Such epistatic interactions were also confirmed in gene expression and histological analyses conducted in the single and double mutants. Although Me phenocopied the high shoot formation of Rg1 on SIM, it failed to increase rooting on RIM and to rescue the non-branching phenotype of ls. Taken together, these results suggest REGENERATION1 and the DELLA mutant PROCERA as controlling a common competence to assume distinct cell fates, rather than the specific induction of adventitious roots or shoots, which is controlled by DIAGEOTROPICA and MOUSE EARS, respectively. PMID:22915742

The tomato (Solanum lycopersicum cv. Micro-Tom) natural genetic variation Rg1 and the DELLA mutant procera control the competence necessary to form adventitious roots and shoots.

PubMed

Lombardi-Crestana, Simone; da Silva Azevedo, Mariana; e Silva, Geraldo Felipe Ferreira; Pino, Lílian Ellen; Appezzato-da-Glória, Beatriz; Figueira, Antonio; Nogueira, Fabio Tebaldi Silveira; Peres, Lázaro Eustáquio Pereira

2012-09-01

Despite the wide use of plant regeneration for biotechnological purposes, the signals that allow cells to become competent to assume different fates remain largely unknown. Here, it is demonstrated that the Regeneration1 (Rg1) allele, a natural genetic variation from the tomato wild relative Solanum peruvianum, increases the capacity to form both roots and shoots in vitro; and that the gibberellin constitutive mutant procera (pro) presented the opposite phenotype, reducing organogenesis on either root-inducing medium (RIM) or shoot-inducing medium (SIM). Mutants showing alterations in the formation of specific organs in vitro were the auxin low-sensitivity diageotropica (dgt), the lateral suppresser (ls), and the KNOX-overexpressing Mouse ears (Me). dgt failed to form roots on RIM, Me increased shoot formation on SIM, and the high capacity for in vitro shoot formation of ls contrasted with its recalcitrance to form axillary meristems. Interestingly, Rg1 rescued the in vitro organ formation capacity in proRg1 and dgtRg1 double mutants and the ex vitro low lateral shoot formation in pro and ls. Such epistatic interactions were also confirmed in gene expression and histological analyses conducted in the single and double mutants. Although Me phenocopied the high shoot formation of Rg1 on SIM, it failed to increase rooting on RIM and to rescue the non-branching phenotype of ls. Taken together, these results suggest REGENERATION1 and the DELLA mutant PROCERA as controlling a common competence to assume distinct cell fates, rather than the specific induction of adventitious roots or shoots, which is controlled by DIAGEOTROPICA and MOUSE EARS, respectively.

A re-assessment of sucrose signaling involved in cluster-root formation and function in phosphate-deficient white lupin (Lupinus albus).

PubMed

Wang, Zhengrui; Shen, Jianbo; Ludewig, Uwe; Neumann, Günter

2015-07-01

Apart from substrate functions, a signaling role of sucrose in root growth regulation is well established. This raised the question whether sucrose signals might also be involved in formation of cluster-roots (CRs) under phosphate (Pi) limitation, mediating exudation of phosphorus (P)-mobilizing root exudates, e.g. in Lupinus albus and members of the Proteaceae. Earlier studies demonstrated that CR formation in L. albus was mimicked to some extent by external application of high sucrose concentrations (25 mM) in the presence of extremely high P supply (1-10 mM), usually suppressing CR formation. In this study, we re-addressed this question using an axenic hydroponic culture system with normal P supply (0.1 mM) and a range of sucrose applications (0.25-25 mM). The 2.5 mM sucrose concentration was comparable with internal sucrose levels in the zone of CR initiation in first-order laterals of P-deficient plants (3.4 mM) and induced the same CR morphology. Similar to earlier studies, high sucrose concentrations (25 mM) resulted in root thickening and inhibition of root elongation, associated with a 10-fold increase of the internal sucrose level. The sucrose analog palatinose and a combination of glucose/fructose failed to stimulate CR formation under P-sufficient conditions, demonstrating a signal function of sucrose and excluding osmotic or carbon source effects. In contrast to earlier findings, sucrose was able to induce CR formation but had no effect on CR functioning with respect to citrate exudation, in vitro activity and expression of genes encoding phosphoenolpyruvate carboxylase, secretory acid phosphatase and MATE transporters, mediating P-mobilizing functions of CRs. © 2014 Scandinavian Plant Physiology Society.

Transcriptomic and anatomical complexity of primary, seminal, and crown roots highlight root type-specific functional diversity in maize (Zea mays L.).

PubMed

Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank

2016-02-01

Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Expression of insulin-like growth factor-1 and proliferating cell nuclear antigen in human pulp cells of teeth with complete and incomplete root development.

PubMed

Caviedes-Bucheli, J; Canales-Sánchez, P; Castrillón-Sarria, N; Jovel-Garcia, J; Alvarez-Vásquez, J; Rivero, C; Azuero-Holguín, M M; Diaz, E; Munoz, H R

2009-08-01

To quantify the expression of insulin-like growth factor-1 (IGF-1) and proliferating cell nuclear antigen (PCNA) in human pulp cells of teeth with complete or incomplete root development, to support the specific role of IGF-1 in cell proliferation during tooth development and pulp reparative processes. Twenty six pulp samples were obtained from freshly extracted human third molars, equally divided in two groups according to root development stage (complete or incomplete root development). All samples were processed and immunostained to determine the expression of IGF-1 and PCNA in pulp cells. Sections were observed with a light microscope at 80x and morphometric analyses were performed to calculate the area of PCNA and IGF-1 immunostaining using digital image software. Mann-Whitney's test was used to determine statistically significant differences between groups (P < 0.05) for each peptide and the co-expression of both. Expression of IGF-1 and PCNA was observed in all human pulp samples with a statistically significant higher expression in cells of pulps having complete root development (P = 0.0009). Insulin-like growth factor-1 and PCNA are expressed in human pulp cells, with a significant greater expression in pulp cells of teeth having complete root development.

Analysis of integrated multiple 'omics' datasets reveals the mechanisms of initiation and determination in the formation of tuberous roots in Rehmannia glutinosa.

PubMed

Li, Mingjie; Yang, Yanhui; Li, Xinyu; Gu, Li; Wang, Fengji; Feng, Fajie; Tian, Yunhe; Wang, Fengqing; Wang, Xiaoran; Lin, Wenxiong; Chen, Xinjian; Zhang, Zhongyi

2015-09-01

All tuberous roots in Rehmannia glutinosa originate from the expansion of fibrous roots (FRs), but not all FRs can successfully transform into tuberous roots. This study identified differentially expressed genes and proteins associated with the expansion of FRs, by comparing the tuberous root at expansion stages (initiated tuberous root, ITRs) and FRs at the seedling stage (initiated FRs, IFRs). The role of miRNAs in the expansion of FRs was also explored using the sRNA transcriptome and degradome to identify miRNAs and their target genes that were differentially expressed between ITRs and FRs at the mature stage (unexpanded FRs, UFRs, which are unable to expand into ITRs). A total of 6032 genes and 450 proteins were differentially expressed between ITRs and IFRs. Integrated analyses of these data revealed several genes and proteins involved in light signalling, hormone response, and signal transduction that might participate in the induction of tuberous root formation. Several genes related to cell division and cell wall metabolism were involved in initiating the expansion of IFRs. Of 135 miRNAs differentially expressed between ITRs and UFRs, there were 27 miRNAs whose targets were specifically identified in the degradome. Analysis of target genes showed that several miRNAs specifically expressed in UFRs were involved in the degradation of key genes required for the formation of tuberous roots. As far as could be ascertained, this is the first time that the miRNAs that control the transition of FRs to tuberous roots in R. glutinosa have been identified. This comprehensive analysis of 'omics' data sheds new light on the mechanisms involved in the regulation of tuberous roots formation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Dark exposure of petunia cuttings strongly improves adventitious root formation and enhances carbohydrate availability during rooting in the light.

PubMed

Klopotek, Yvonne; Haensch, Klaus-Thomas; Hause, Bettina; Hajirezaei, Mohammad-Reza; Druege, Uwe

2010-05-01

The effect of temporary dark exposure on adventitious root formation (ARF) in Petuniaxhybrida 'Mitchell' cuttings was investigated. Histological and metabolic changes in the cuttings during the dark treatment and subsequent rooting in the light were recorded. Excised cuttings were exposed to the dark for seven days at 10 degrees C followed by a nine-day rooting period in perlite or were rooted immediately for 16 days in a climate chamber at 22/20 degrees C (day/night) and a photosynthetic photon flux density (PPFD) of 100micromolm(-2)s(-1). Dark exposure prior to rooting increased, accelerated and synchronized ARF. The rooting period was reduced from 16 days (non-treated cuttings) to 9 days (treated cuttings). Under optimum conditions, despite the reduced rooting period, dark-exposed cuttings produced a higher number and length of roots than non-treated cuttings. An increase in temperature to 20 degrees C during the dark treatment or extending the cold dark exposure to 14 days caused a similar enhancement of root development compared to non-treated cuttings. Root meristem formation had already started during the dark treatment and was enhanced during the subsequent rooting period. Levels of soluble sugars (glucose, fructose and sucrose) and starch in leaf and basal stem tissues significantly decreased during the seven days of dark exposure. This depletion was, however, compensated during rooting after 6 and 24h for soluble sugars in leaves and the basal stem, respectively, whereas the sucrose level in the basal stem was already increased at 6h. The association of higher carbohydrate levels with improved rooting in previously dark-exposed versus non-treated cuttings indicates that increased post-darkness carbohydrate availability and allocation towards the stem base contribute to ARF under the influence of dark treatment and provide energy for cell growth subject to a rising sink intensity in the base of the cutting. Copyright 2009 Elsevier GmbH. All rights reserved.

Effect of phorbol derivatives and staurosporine on gravitropic response of primary root of maize

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulkey, T.J.; Kim, S.Y.; Lee, J.S.

1991-05-01

Time-lapse videography and computer-based, video image digitization were used to examine the effects of phorbol derivatives (phorbol 12-myristate 13-acetate, TPA; phorbol 12-myristate 13-acetate 4-O-methyl ether, mTPA) and staurosporine on the kinetics of gravicurvature of primary roots of maize (Zea mays L., Pioneer 3343 and Golden Cross Bantam). Pretreatment of roots with TPA (3 hr, 1 {mu}M) decreases the time lag prior to induction of positive gravicurvature in horizontally-oriented roots by > 60%. The rate of curvature is not significantly different than the rate observed in control roots. Wrongway curvature which is observed in 30-40% of control roots is not observedmore » in TPA-pretreated roots. Oscillatory movements observed in control roots after completion of gravitropic reorientation is completely dampened in TPA-pretreated roots. Pretreatment of roots with mTPA(3hr,1{mu}M), the inactive analog of TPA, does not significantly alter the kinetics of gravicurvature of primary roots of maize. Staurosporine (10{sup {minus}8}M), a microbial alkaloid which has been reported to have antifungal activity and to inhibit phospholipid/Ca{sup ++} dependent protein kinase, completely inhibits TPA-induced alteration of the kinetics of gravitropism. DAG (1-oleoyl-2-acetyl-rac-glycerol), a synthetic diglyceride activator of protein kinase C, exhibits similar activity to TPA. TPA-induced alterations in tissue response to auxin are presented.« less

The GLABRA2 homeodomain protein directly regulates CESA5 and XTH17 gene expression in Arabidopsis roots.

PubMed

Tominaga-Wada, Rumi; Iwata, Mineko; Sugiyama, Junji; Kotake, Toshihisa; Ishida, Tetsuya; Yokoyama, Ryusuke; Nishitani, Kazuhiko; Okada, Kiyotaka; Wada, Takuji

2009-11-01

Arabidopsis root hair formation is determined by the patterning genes CAPRICE (CPC), GLABRA3 (GL3), WEREWOLF (WER) and GLABRA2 (GL2), but little is known about the later changes in cell wall material during root hair formation. A combined Fourier-transform infrared microspectroscopy-principal components analysis (FTIR-PCA) method was used to detect subtle differences in the cell wall material between wild-type and root hair mutants in Arabidopsis. Among several root hair mutants, only the gl2 mutation affected root cell wall polysaccharides. Five of the 10 genes encoding cellulose synthase (CESA1-10) and 4 of 33 xyloglucan endotransglucosylase (XTH1-33) genes in Arabidopsis are expressed in the root, but only CESA5 and XTH17 were affected by the gl2 mutation. The L1-box sequence located in the promoter region of these genes was recognized by the GL2 protein. These results indicate that GL2 directly regulates cell wall-related gene expression during root development.

Shoot size significantly affects rooting response of sugar maple softwood cuttings

Treesearch

John R. Donnelly

1974-01-01

Three hundred softwood cuttings were collected from each of three mature sugar maple trees to test the effect of shoot size on adventitious root formation. One of the trees was a good rooter (61 percent rooted); one was a poor rooter (19 percent rooted); and the third was a non-rooter (1 percent rooted). There was an insufficient number of rooted cuttings from the...

Do radial oxygen loss and external aeration affect iron plaque formation and arsenic accumulation and speciation in rice?

PubMed Central

Wu, Chuan; Ye, Zhihong; Li, Hui; Wu, Shengchun; Deng, Dan; Zhu, Yongguan; Wong, Minghung

2012-01-01

Hydroponic experiments were conducted to investigate the effect of radial oxygen loss (ROL) and external aeration on iron (Fe) plaque formation, and arsenic (As) accumulation and speciation in rice (Oryza sativa L.). The data showed that there were significant correlations between ROL and Fe concentrations in Fe plaque produced on different genotypes of rice. There were also significant differences in the amounts of Fe plaque formed between different genotypes in different positions of roots and under different aeration conditions (aerated, normal, and stagnant treatments). In aerated treatments, rice tended to have a higher Fe plaque formation than in a stagnant solution, with the greatest formation at the root tip decreasing with increasing distances away, in accordance with a trend of spatial ROL. Genotypes with higher rates of ROL induced higher degrees of Fe plaque formation. Plaques sequestered As on rice roots, with arsenate almost double that with arsenite, leading to decreased As accumulation in both roots and shoots. The major As species detected in roots and shoots was arsenite, ranging from 34 to 78% of the total As in the different treatments and genotypes. These results contribute to our understanding of genotypic differences in As uptake by rice and the mechanisms causing rice genotypes with higher ROL to show lower overall As accumulation. PMID:22345639

Identification of a hydrolyzable tannin, oenothein B, as an aluminum-detoxifying ligand in a highly aluminum-resistant tree, Eucalyptus camaldulensis.

PubMed

Tahara, Ko; Hashida, Koh; Otsuka, Yuichiro; Ohara, Seiji; Kojima, Katsumi; Shinohara, Kenji

2014-02-01

Eucalyptus camaldulensis is a tree species in the Myrtaceae that exhibits extremely high resistance to aluminum (Al). To explore a novel mechanism of Al resistance in plants, we examined the Al-binding ligands in roots and their role in Al resistance of E. camaldulensis. We identified a novel type of Al-binding ligand, oenothein B, which is a dimeric hydrolyzable tannin with many adjacent phenolic hydroxyl groups. Oenothein B was isolated from root extracts of E. camaldulensis by reverse-phase high-performance liquid chromatography and identified by nuclear magnetic resonance and mass spectrometry analyses. Oenothein B formed water-soluble or -insoluble complexes with Al depending on the ratio of oenothein B to Al and could bind at least four Al ions per molecule. In a bioassay using Arabidopsis (Arabidopsis thaliana), Al-induced inhibition of root elongation was completely alleviated by treatment with exogenous oenothein B, which indicated the capability of oenothein B to detoxify Al. In roots of E. camaldulensis, Al exposure enhanced the accumulation of oenothein B, especially in EDTA-extractable forms, which likely formed complexes with Al. Oenothein B was localized mostly in the root symplast, in which a considerable amount of Al accumulated. In contrast, oenothein B was not detected in three Al-sensitive species, comprising the Myrtaceae tree Melaleuca bracteata, Populus nigra, and Arabidopsis. Oenothein B content in roots of five tree species was correlated with their Al resistance. Taken together, these results suggest that internal detoxification of Al by the formation of complexes with oenothein B in roots likely contributes to the high Al resistance of E. camaldulensis.

Identification of a Hydrolyzable Tannin, Oenothein B, as an Aluminum-Detoxifying Ligand in a Highly Aluminum-Resistant Tree, Eucalyptus camaldulensis1[C][W

PubMed Central

Tahara, Ko; Hashida, Koh; Otsuka, Yuichiro; Ohara, Seiji; Kojima, Katsumi; Shinohara, Kenji

2014-01-01

Eucalyptus camaldulensis is a tree species in the Myrtaceae that exhibits extremely high resistance to aluminum (Al). To explore a novel mechanism of Al resistance in plants, we examined the Al-binding ligands in roots and their role in Al resistance of E. camaldulensis. We identified a novel type of Al-binding ligand, oenothein B, which is a dimeric hydrolyzable tannin with many adjacent phenolic hydroxyl groups. Oenothein B was isolated from root extracts of E. camaldulensis by reverse-phase high-performance liquid chromatography and identified by nuclear magnetic resonance and mass spectrometry analyses. Oenothein B formed water-soluble or -insoluble complexes with Al depending on the ratio of oenothein B to Al and could bind at least four Al ions per molecule. In a bioassay using Arabidopsis (Arabidopsis thaliana), Al-induced inhibition of root elongation was completely alleviated by treatment with exogenous oenothein B, which indicated the capability of oenothein B to detoxify Al. In roots of E. camaldulensis, Al exposure enhanced the accumulation of oenothein B, especially in EDTA-extractable forms, which likely formed complexes with Al. Oenothein B was localized mostly in the root symplast, in which a considerable amount of Al accumulated. In contrast, oenothein B was not detected in three Al-sensitive species, comprising the Myrtaceae tree Melaleuca bracteata, Populus nigra, and Arabidopsis. Oenothein B content in roots of five tree species was correlated with their Al resistance. Taken together, these results suggest that internal detoxification of Al by the formation of complexes with oenothein B in roots likely contributes to the high Al resistance of E. camaldulensis. PMID:24381064

Interactions between light intensity and phosphorus nutrition affect the phosphate-mining capacity of white lupin (Lupinus albus L.).

PubMed

Cheng, Lingyun; Tang, Xiaoyan; Vance, Carroll P; White, Philip J; Zhang, Fusuo; Shen, Jianbo

2014-07-01

Light intensity affects photosynthetic carbon (C) fixation and the supply of carbon to roots. To evaluate interactions between carbon supply and phosphorus (P) supply, effects of light intensity on sucrose accumulation, root growth, cluster root formation, carboxylate exudation, and P uptake capacity were studied in white lupin (Lupinus albus L.) grown hydroponically with either 200 µmol m(-2) s(-1) or 600 µmol m(-2) s(-1) light and a sufficient (50 µM P) or deficient (1 µM P) P supply. Plant biomass and root:shoot ratio increased with increasing light intensity, particularly when plants were supplied with sufficient P. Both low P supply and increasing light intensity increased the production of cluster roots and citrate exudation. Transcripts of a phosphoenol pyruvate carboxylase gene (LaPEPC3) in cluster roots (which is related to the exudation of citrate), transcripts of a phosphate transporter gene (LaPT1), and P uptake all increased with increasing light intensity, under both P-sufficient and P-deficient conditions. Across all four experimental treatments, increased cluster root formation and carboxylate exudation were associated with lower P concentration in the shoot and greater sucrose concentration in the roots. It is suggested that C in excess of shoot growth capabilities is translocated to the roots as sucrose, which serves as both a nutritional signal and a C-substrate for carboxylate exudation and cluster root formation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Nitric Oxide Affects Rice Root Growth by Regulating Auxin Transport Under Nitrate Supply

PubMed Central

Sun, Huwei; Feng, Fan; Liu, Juan; Zhao, Quanzhi

2018-01-01

Nitrogen (N) is a major essential nutrient for plant growth, and rice is an important food crop globally. Although ammonium (NH4+) is the main N source for rice, nitrate (NO3-) is also absorbed and utilized. Rice responds to NO3- supply by changing root morphology. However, the mechanisms of rice root growth and formation under NO3- supply are unclear. Nitric oxide (NO) and auxin are important regulators of root growth and development under NO3- supply. How the interactions between NO and auxin in regulating root growth in response to NO3- are unknown. In this study, the levels of indole-3-acetic acid (IAA) and NO in roots, and the responses of lateral roots (LRs) and seminal roots (SRs) to NH4+ and NO3-, were investigated using wild-type (WT) rice, as well as osnia2 and ospin1b mutants. NO3- supply promoted LR formation and SR elongation. The effects of NO donor and NO inhibitor/scavenger supply on NO levels and the root morphology of WT and nia2 mutants under NH4+ or NO3- suggest that NO3--induced NO is generated by the nitrate reductase (NR) pathway rather than the NO synthase (NOS)-like pathway. IAA levels, [3H] IAA transport, and PIN gene expression in roots were enhanced under NO3- relative to NH4+ supply. These results suggest that NO3- regulates auxin transport in roots. Application of SNP under NH4+ supply, or of cPTIO under NO3- supply, resulted in auxin levels in roots similar to those under NO3- and NH4+ supply, respectively. Compared to WT, the roots of the ospin1b mutant had lower auxin levels, fewer LRs, and shorter SRs. Thus, NO affects root growth by regulating auxin transport in response to NO3-. Overall, our findings suggest that NO3- influences LR formation and SR elongation by regulating auxin transport via a mechanism involving NO. PMID:29875779

Growth and anatomical parameters of adventitious roots formed on mung bean hypocotyls are correlated with galactoglucomannan oligosaccharides structure.

PubMed

Kollárová, K; Zelko, I; Henselová, M; Capek, P; Lišková, D

2012-01-01

The effect of galactoglucomannan oligosaccharides (GGMOs) compared with chemically modified oligosaccharides, GGMOs-g (with reduced number of D-galactose side chains) and GGMOs-r (with reduced reducing ends) on mung bean (Vigna radiata (L.) Wilczek) adventitious roots formation, elongation, and anatomical structure have been studied. All types of oligosaccharides influenced adventitious root formation in the same way: stimulation in the absence of exogenous auxin and inhibition in the presence of exogenous auxin. Both reactions are probably related with the presence/content of endogenous auxin in plant cuttings. However, the adventitious root length was inhibited by GGMOs both in the absence as well as in the presence of auxin (IBA or NAA), while GGMOs-g inhibition was significantly weaker compared with GGMOs. GGMOs-r were without significant difference on both processes, compared with GGMOs. GGMOs affected not only the adventitious root length but also their anatomy in dependence on the combination with certain type of auxin. The oligosaccharides influenced cortical cells division, which was reflected in the cortex area and in the root diameter. All processes followed were dependent on oligosaccharides chemical structure. The results suggest also that GGM-derived oligosaccharides may play an important role in adventitious roots elongation but not in their formation.

Growth and Anatomical Parameters of Adventitious Roots Formed on Mung Bean Hypocotyls Are Correlated with Galactoglucomannan Oligosaccharides Structure

PubMed Central

Kollárová, K.; Zelko, I.; Henselová, M.; Capek, P.; Lišková, D.

2012-01-01

The effect of galactoglucomannan oligosaccharides (GGMOs) compared with chemically modified oligosaccharides, GGMOs-g (with reduced number of D-galactose side chains) and GGMOs-r (with reduced reducing ends) on mung bean (Vigna radiata (L.) Wilczek) adventitious roots formation, elongation, and anatomical structure have been studied. All types of oligosaccharides influenced adventitious root formation in the same way: stimulation in the absence of exogenous auxin and inhibition in the presence of exogenous auxin. Both reactions are probably related with the presence/content of endogenous auxin in plant cuttings. However, the adventitious root length was inhibited by GGMOs both in the absence as well as in the presence of auxin (IBA or NAA), while GGMOs-g inhibition was significantly weaker compared with GGMOs. GGMOs-r were without significant difference on both processes, compared with GGMOs. GGMOs affected not only the adventitious root length but also their anatomy in dependence on the combination with certain type of auxin. The oligosaccharides influenced cortical cells division, which was reflected in the cortex area and in the root diameter. All processes followed were dependent on oligosaccharides chemical structure. The results suggest also that GGM-derived oligosaccharides may play an important role in adventitious roots elongation but not in their formation. PMID:22666154

Proliferation and ajmalicine biosynthesis of Catharanthus roseus (L). G. Don adventitious roots in self-built temporary immersion system

NASA Astrophysics Data System (ADS)

Phuc, Vo Thanh; Trung, Nguyen Minh; Thien, Huynh Tri; Tien, Le Thi Thuy

2017-09-01

Periwinkle (Catharanthus roseus (L.) G. Don) is a medicinal plant containing about 130 types of alkaloids that have important pharmacological effects. Ajmalicine in periwinkle root is an antihypertensive drug used in treatment of high blood pressure. Adventitious roots obtained from periwinkle leaves of in vitro shoots grew well in quarter-strength MS medium supplemented with 0.3 mg/l IBA and 20 g/l sucrose. Dark condition was more suitable for root growth than light. However, callus formation also took place in addition to the growth of adventitious roots. Temporary immersion system was applied in the culture of adventitious roots in order to reduce the callus growth rate formed in shake flask cultures. The highest growth index of roots was achieved using the system with 5-min immersion every 45 min (1.676 ± 0.041). The roots cultured in this system grew well without callus formation. Ajmalicine content was highest in the roots cultured with 5-min immersion every 180 min (950 μg/g dry weight).

Transcriptome-wide mining suggests conglomerate of genes associated with tuberous root growth and development in Aconitum heterophyllum Wall.

PubMed

Malhotra, Nikhil; Sood, Hemant; Chauhan, Rajinder Singh

2016-12-01

Tuberous roots of Aconitum heterophyllum constitute storage organ for secondary metabolites, however, molecular components contributing to their formation are not known. The transcriptomes of A. heterophyllum were analyzed to identify possible genes associated with tuberous root development by taking clues from genes implicated in other plant species. Out of 18 genes, eight genes encoding GDP-mannose pyrophosphorylase (GMPase), SHAGGY, Expansin, RING-box protein 1 (RBX1), SRF receptor kinase (SRF), β-amylase, ADP-glucose pyrophosphorylase (AGPase) and Auxin responsive factor 2 (ARF2) showed higher transcript abundance in roots (13-171 folds) compared to shoots. Comparative expression analysis of those genes between tuberous root developmental stages showed 11-97 folds increase in transcripts in fully developed roots compared to young rootlets, thereby implying their association in biosynthesis, accumulation and storage of primary metabolites towards root biomass. Cluster analysis revealed a positive correlation with the gene expression data for different stages of tuberous root formation in A. heterophyllum. The outcome of this study can be useful in genetic improvement of A. heterophyllum for root biomass yield.

Root Cortical Aerenchyma Enhances the Growth of Maize on Soils with Suboptimal Availability of Nitrogen, Phosphorus, and Potassium1[W][OA

PubMed Central

Postma, Johannes Auke; Lynch, Jonathan Paul

2011-01-01

Root cortical aerenchyma (RCA) is induced by hypoxia, drought, and several nutrient deficiencies. Previous research showed that RCA formation reduces the respiration and nutrient content of root tissue. We used SimRoot, a functional-structural model, to provide quantitative support for the hypothesis that RCA formation is a useful adaptation to suboptimal availability of phosphorus, nitrogen, and potassium by reducing the metabolic costs of soil exploration in maize (Zea mays). RCA increased the growth of simulated 40-d-old maize plants up to 55%, 54%, or 72% on low nitrogen, phosphorus, or potassium soil, respectively, and reduced critical fertility levels by 13%, 12%, or 7%, respectively. The greater utility of RCA on low-potassium soils is associated with the fact that root growth in potassium-deficient plants was more carbon limited than in phosphorus- and nitrogen-deficient plants. In contrast to potassium-deficient plants, phosphorus- and nitrogen-deficient plants allocate more carbon to the root system as the deficiency develops. The utility of RCA also depended on other root phenes and environmental factors. On low-phosphorus soils (7.5 μm), the utility of RCA was 2.9 times greater in plants with increased lateral branching density than in plants with normal branching. On low-nitrate soils, the utility of RCA formation was 56% greater in coarser soils with high nitrate leaching. Large genetic variation in RCA formation and the utility of RCA for a range of stresses position RCA as an interesting crop-breeding target for enhanced soil resource acquisition. PMID:21628631

Aspen Root Sucker Formation and Apical Dominance

Treesearch

Robert E. Farmer

1962-01-01

Root suckering is the primary mode of regeneration in the aspens, Populus tremuloides Michx. and P. grandidentata Michx. When stems of these species are cut, numerous suckers originating in the root pericycle are formed on their extensive lateral root systems. During their first season of growth, suckers ordinarily reach a height...

UV-B Induced Generation of Reactive Oxygen Species Promotes Formation of BFA-Induced Compartments in Cells of Arabidopsis Root Apices

PubMed Central

Yokawa, Ken; Kagenishi, Tomoko; Baluška, František

2016-01-01

UV-B radiation is an important part of the electromagnetic spectrum emitted by the sun. For much of the period of biological evolution organisms have been exposed to UV radiation, and have developed diverse mechanisms to cope with this potential stress factor. Roots are usually shielded from exposure to UV by the surrounding soil, but may nevertheless be exposed to high energy radiation on the soil surface. Due to their high sensitivity to UV-B radiation, plant roots need to respond rapidly in order to minimize exposure on the surface. In addition to root gravitropism, effective light perception by roots has recently been discovered to be essential for triggering negative root phototropism in Arabidopsis. However, it is not fully understood how UV-B affects root growth and phototropism. Here, we report that UV-B induces rapid generation of reactive oxygen species which in turn promotes the formation of BFA-induced compartments in the Arabidopsis root apex. During unilateral UV-B irradiation of roots changes in auxin concentration on the illuminated side have been recorded. In conclusion, UV-B-induced and ROS-mediated stimulation of vesicle recycling promotes root growth and induces negative phototropism. PMID:26793199

Halogenated auxins affect microtubules and root elongation in Lactuca sativa

NASA Technical Reports Server (NTRS)

Zhang, N.; Hasenstein, K. H.

2000-01-01

We studied the effect of 4,4,4-trifluoro-3-(indole-3-)butyric acid (TFIBA), a recently described root growth stimulator, and 5,6-dichloro-indole-3-acetic acid (DCIAA) on growth and microtubule (MT) organization in roots of Lactuca sativa L. DCIAA and indole-3-butyric acid (IBA) inhibited root elongation and depolymerized MTs in the cortex of the elongation zone, inhibited the elongation of stele cells, and promoted xylem maturation. Both auxins caused the plane of cell division to shift from anticlinal to periclinal. In contrast, TFIBA (100 micromolar) promoted elongation of primary roots by 40% and stimulated the elongation of lateral roots, even in the presence of IBA, the microtubular inhibitors oryzalin and taxol, or the auxin transport inhibitor naphthylphthalamic acid. However, TFIBA inhibited the formation of lateral root primordia. Immunostaining showed that TFIBA stabilized MTs orientation perpendicular to the root axis, doubled the cortical cell length, but delayed xylem maturation. The data indicate that the auxin-induced inhibition of elongation and swelling of roots results from reoriented phragmoplasts, the destabilization of MTs in elongating cells, and promotion of vessel formation. In contrast, TFIBA induced promotion of root elongation by enhancing cell length, prolonging transverse MT orientation, delaying cell and xylem maturation.

A new method to enhance rhizosheath formation

NASA Astrophysics Data System (ADS)

Ahmadi, katayoun; Zarebanadkouki, Mohsen; Kuzyakov, Yakov; Carminati, Andrea

2016-04-01

The rhizosheath is defined as the soil that adheres to the roots by help of root hairs and mucilage. Rhizosheath maintain the contact between roots and soil improving water and nutrient uptake. Here we introduce: (1) a technique to quantify the formation of rhizosheath around the roots, and (2) a method to enhance the formation of rhizosheath around the roots. Additionally, we measured the relation between rhizosheath thickness and the carbon content and enzyme activities in the rhizosphere. We grew lupine plants in aluminum containers (28×30×1 cm) filled with a sandy soil. When plants were two weeks-old and the soil had a water content of 30%, we stopped the irrigation and let the plants to uptake water to a soil water content of 4-5%. Thereafter, half of the plants (4 plants) were irrigated with water and the other half with water with an additive (international patent is pending). We repeated the drying and rewetting cycle three times. At the end of the third drying cycle, when plants were 40 days old and soil had a water content of 4-5%,the containers were opened and roots and their surrounding soils were gently collected. We used imaging to quantify the rhizosheath formation. The method consists of scanning the roots and the surrounding soil using the Winrhizo software. By image analysis we quantified the thickness of roots and their rhizosheath. The plants irrigated with the additive had 63% thicker rhizopsheath than plants irrigated with water. So, the additive enhanced gelation of mucilage exuded by the roots. Carbon content and enzyme activity in the collected rhizosheath showed that the rhizosheath of plants irrigated with the additive had higher carbon content and enzyme activity than the rhizopsheath of plants irrigated with water. The new method to increase rhizosheath has the great advantage that can be easily applied to the irrigation water to improve plant uptake of water and nutrients in semiarid and arid areas.

Combined periodontic-orthodonticendodontic interdisciplinary approach in the treatment of periodontally compromised tooth

PubMed Central

Deepa, D; Mehta, D. S.; Puri, Viren K.; Shetty, Sadashiva

2010-01-01

Orthodontic treatment in adult patients is one of the most frequently encountered components involving multidisciplinary approaches. In the present report, a 28-year-old male patient was treated for localized chronic periodontitis with pocket formation, mobility, pathologic migration and malalignment of maxillary left lateral incisor tooth #22. The periodontal therapy included motivation, education and oral-hygiene instructions (O.H.I.), scaling and root planing and periodontal flap surgery. Subsequently on resolution of periodontal inflammation, orthodontic therapy was carried out using the orthodontic aligner for a period of 6 months. Post-treatment (3 years) results showed complete resolution of infrabony pocket with significant bone fill, reduced tooth mobility and complete alignment of the affected maxillary left lateral incisor, thus restoring the esthetics and function. PMID:21691554

Quantitative Analysis of Adventitious Root Growth Phenotypes in Carnation Stem Cuttings

PubMed Central

Birlanga, Virginia; Villanova, Joan; Cano, Antonio; Cano, Emilio A.; Acosta, Manuel; Pérez-Pérez, José Manuel

2015-01-01

Carnation is one of the most important species on the worldwide market of cut flowers. Commercial carnation cultivars are vegetatively propagated from terminal stem cuttings that undergo a rooting and acclimation process. For some of the new cultivars that are being developed by ornamental breeders, poor adventitious root (AR) formation limits its commercial scaling-up, due to a significant increase in the production costs. We have initiated a genetical-genomics approach to determine the molecular basis of the differences found between carnation cultivars during adventitious rooting. The detailed characterization of AR formation in several carnation cultivars differing in their rooting losses has been performed (i) during commercial production at a breeders’ rooting station and (ii) on a defined media in a controlled environment. Our study reveals the phenotypic signatures that distinguishes the bad-rooting cultivars and provides the appropriate set-up for the molecular identification of the genes involved in AR development in this species. PMID:26230608

Cell dynamics in cervical loop epithelium during transition from crown to root: implications for Hertwig's epithelial root sheath formation.

PubMed

Sakano, M; Otsu, K; Fujiwara, N; Fukumoto, S; Yamada, A; Harada, H

2013-04-01

Some clinical cases of hypoplastic tooth root are congenital. Because the formation of Hertwig's epithelial root sheath (HERS) is an important event for root development and growth, we have considered that understanding the HERS developmental mechanism contributes to elucidate the causal factors of the disease. To find integrant factors and phenomenon for HERS development and growth, we studied the proliferation and mobility of the cervical loop (CL). We observed the cell movement of CL by the DiI labeling and organ culture system. To examine cell proliferation, we carried out immunostaining of CL and HERS using anti-Ki67 antibody. Cell motility in CL was observed by tooth germ slice organ culture using green fluorescent protein mouse. We also examined the expression of paxillin associated with cell movement. Imaging using DiI labeling showed that, at the apex of CL, the epithelium elongated in tandem with the growth of outer enamel epithelium (OEE). Cell proliferation assay using Ki67 immunostaining showed that OEE divided more actively than inner enamel epithelium (IEE) at the onset of HERS formation. Live imaging suggested that mobility of the OEE and cells in the apex of CL were more active than in IEE. The expression of paxillin was observed strongly in OEE and the apex of CL. The more active growth and movement of OEE cells contributed to HERS formation after reduction of the growth of IEE. The expression pattern of paxillin was involved in the active movement of OEE and HERS. The results will contribute to understand the HERS formation mechanism and elucidate the cause of anomaly root. © 2012 John Wiley & Sons A/S.

Expression of bone morphogenetic proteins and Msx genes during root formation.

PubMed

Yamashiro, T; Tummers, M; Thesleff, I

2003-03-01

Like crown development, root formation is also regulated by interactions between epithelial and mesenchymml tissues. Bone morphogenetic proteins (BMPs), together with the transcription factors Msx1 and Msx2, play important roles in these interactions during early tooth morphogenesis. To investigate the involvement of this signaling pathway in root development, we analyzed the expression patterns of Bmp2, Bmp3, Bmp4, and Bmp7 as well as Msx1 and Msx2 in the roots of mouse molars. Bmp4 was expressed in the apical mesenchyme and Msx2 in the root sheath. However, Bmps were not detected in the root sheath epithelium, and Msx transcripts were absent from the underlying mesenchyme. These findings indicate that this Bmp signaling pathway, required for tooth initiation, does not regulate root development, but we suggest that root shape may be regulated by a mechanism similar to that regulating crown shape in cap-stage tooth germs. Msx2 expression continued in the epithelial cell rests of Malassez, and the nearby cementoblasts intensely expressed Bmp3, which may regulate some functions of the fragmented epithelium.

Binding of isolated plant lectin by rhizobia during episodes of reduced gravity obtained by parabolic flight

NASA Technical Reports Server (NTRS)

Henry, R. L.; Green, P. D.; Wong, P. P.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)

1990-01-01

Development of a legume root nodule is a complex process culminating in a plant/bacterial symbiosis possessing the capacity for biological dinitrogen fixation. Formation of root nodules is initiated by the binding and stabilization of rhizobia to plant root hairs, mediated in part by a receptor/ligand recognition system composed of lectins on the plant root surface and lectin-binding sites on the rhizobial cell surface. The dinitrogen fixation activity of these root nodules may be an important feature of enclosed, space-based life support systems, and may provide an ecological method to recycle nitrogen for amino acid production. However, the effects on nodule development of varied gravitational fields, or of root nutrient delivery hardware, remain unknown. We have investigated the effects of microgravity on root nodule formation, with preliminary experiments focused upon the receptor/ligand component. Microgravity, obtained during parabolic flight aboard NASA 930, has no apparent effect on the binding of purified lectin to rhizobia, a result that will facilitate forthcoming experiments using intact root tissues.

A comprehensive phylogeny of auxin homeostasis genes involved in adventitious root formation in carnation stem cuttings.

PubMed

Sánchez-García, Ana Belén; Ibáñez, Sergio; Cano, Antonio; Acosta, Manuel; Pérez-Pérez, José Manuel

2018-01-01

Understanding the functional basis of auxin homeostasis requires knowledge about auxin biosynthesis, auxin transport and auxin catabolism genes, which is not always directly available despite the recent whole-genome sequencing of many plant species. Through sequence homology searches and phylogenetic analyses on a selection of 11 plant species with high-quality genome annotation, we identified the putative gene homologs involved in auxin biosynthesis, auxin catabolism and auxin transport pathways in carnation (Dianthus caryophyllus L.). To deepen our knowledge of the regulatory events underlying auxin-mediated adventitious root formation in carnation stem cuttings, we used RNA-sequencing data to confirm the expression profiles of some auxin homeostasis genes during the rooting of two carnation cultivars with different rooting behaviors. We also confirmed the presence of several auxin-related metabolites in the stem cutting tissues. Our findings offer a comprehensive overview of auxin homeostasis genes in carnation and provide a solid foundation for further experiments investigating the role of auxin homeostasis in the regulation of adventitious root formation in carnation.

A comprehensive phylogeny of auxin homeostasis genes involved in adventitious root formation in carnation stem cuttings

PubMed Central

Cano, Antonio; Acosta, Manuel

2018-01-01

Understanding the functional basis of auxin homeostasis requires knowledge about auxin biosynthesis, auxin transport and auxin catabolism genes, which is not always directly available despite the recent whole-genome sequencing of many plant species. Through sequence homology searches and phylogenetic analyses on a selection of 11 plant species with high-quality genome annotation, we identified the putative gene homologs involved in auxin biosynthesis, auxin catabolism and auxin transport pathways in carnation (Dianthus caryophyllus L.). To deepen our knowledge of the regulatory events underlying auxin-mediated adventitious root formation in carnation stem cuttings, we used RNA-sequencing data to confirm the expression profiles of some auxin homeostasis genes during the rooting of two carnation cultivars with different rooting behaviors. We also confirmed the presence of several auxin-related metabolites in the stem cutting tissues. Our findings offer a comprehensive overview of auxin homeostasis genes in carnation and provide a solid foundation for further experiments investigating the role of auxin homeostasis in the regulation of adventitious root formation in carnation. PMID:29709027

Effects of medial meniscal posterior horn avulsion and repair on meniscal displacement.

PubMed

Hein, Christopher N; Deperio, Jennifer Gurske; Ehrensberger, Mark T; Marzo, John M

2011-06-01

Medial meniscal posterior root avulsion (MMRA) leads to deleterious alteration of medial joint compartment loading profiles and increased risk of medial degenerative changes. Surgical repair restores more normal biomechanics to the knee. Our hypothesis is that MMRA will cause medial meniscal (MM) extrusion and gap formation between the root attachment site and MM. Meniscal root repair will restore the ability of the meniscus to resist extrusion, and reduce gap formation at the defect. Seven fresh frozen human cadaveric knees were dissected and mechanically loaded using a servo-hydraulic load frame (MTS ®) with 0 and 1800 N. The knees were tested under three conditions: native, avulsed, and repaired. Four measurements were obtained: meniscal displacement anteriorly, medially, posteriorly, and gap distance between the root attachment site and MM after transection and repair. The medial displacement of the avulsed MM (3.28 mm) was significantly greater (p < 0.001) than the native knee (1.60mm) and repaired knee (1.46 mm). Gap formation is significantly larger in the avulsed compared to repaired state at 0 (p < 0.02) and 1800N (p < 0.02) and also larger with loading in both avulsed (p < 0.05) and repaired (p < 0.02) conditions. Therefore, MMRA results in MM extrusion from the joint and gap formation between the MM root and the MM. Subsequent surgical repair reduces meniscal displacement and gap formation at the defect. Copyright © 2010 Elsevier B.V. All rights reserved.

Azacytidine and miR156 promote rooting in adult but not in juvenile Arabidopsis tissues.

PubMed

Massoumi, Mehdi; Krens, Frans A; Visser, Richard G F; De Klerk, Geert-Jan M

2017-01-01

Poor adventitious root (AR) formation is a major obstacle in micropropagation and conventional vegetative propagation of many crops. It is affected by many endogenous and exogenous factors. With respect to endogenous factors, the phase change from juvenile to adult has a major influence on AR formation and rooting is usually much reduced or even fully inhibited in adult tissues. It has been reported that the phase change is characterized by an increase in DNA-methylation and a decrease in the expression of microRNA156 (miR156). In this paper, we examined the effect of azacytidine (AzaC) and miR156 on AR formation in adult and juvenile Arabidopsis tissues. To identify the ontogenetic state researchers have used flowering or leaf morphology. We have used the rootability which allows - in contrast with both other characteristics- to examine the ontogenetic state at the cellular level. Overexpression of miR156 promoted only the rooting of adult tissues indicating that the phase change-associated loss in tissues' competence to develop ARs is also under the control of miR156. Azacytidine inhibits DNA methylation during DNA replication. Azacytidine treatment also promoted AR formation in nonjuvenile tissues but had no or little effect in juvenile tissues. Its addition during seedling growth (by which all tissues become hypomethylated) or during the rooting treatment (by which only those cells become hypomethylated that are generated after taking the explant) are both effective in the promotion of rooting. An AzaC treatment may be useful in tissue culture for crops that are recalcitrant to root. Copyright © 2016 Elsevier GmbH. All rights reserved.

Nitrate induction of root hair density is mediated by TGA1/TGA4 and CPC transcription factors in Arabidopsis thaliana.

PubMed

Canales, Javier; Contreras-López, Orlando; Álvarez, José M; Gutiérrez, Rodrigo A

2017-10-01

Root hairs are specialized cells that are important for nutrient uptake. It is well established that nutrients such as phosphate have a great influence on root hair development in many plant species. Here we investigated the role of nitrate on root hair development at a physiological and molecular level. We showed that nitrate increases root hair density in Arabidopsis thaliana. We found that two different root hair defective mutants have significantly less nitrate than wild-type plants, suggesting that in A. thaliana root hairs have an important role in the capacity to acquire nitrate. Nitrate reductase-null mutants exhibited nitrate-dependent root hair phenotypes comparable with wild-type plants, indicating that nitrate is the signal that leads to increased formation of root hairs. We examined the role of two key regulators of root hair cell fate, CPC and WER, in response to nitrate treatments. Phenotypic analyses of these mutants showed that CPC is essential for nitrate-induced responses of root hair development. Moreover, we showed that NRT1.1 and TGA1/TGA4 are required for pathways that induce root hair development by suppression of longitudinal elongation of trichoblast cells in response to nitrate treatments. Our results prompted a model where nitrate signaling via TGA1/TGA4 directly regulates the CPC root hair cell fate specification gene to increase formation of root hairs in A. thaliana. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Phosphate Availability Alters Architecture and Causes Changes in Hormone Sensitivity in the Arabidopsis Root System1

PubMed Central

López-Bucio, José; Hernández-Abreu, Esmeralda; Sánchez-Calderón, Lenin; Nieto-Jacobo, María Fernanda; Simpson, June; Herrera-Estrella, Luis

2002-01-01

The postembryonic developmental program of the plant root system is plastic and allows changes in root architecture to adapt to environmental conditions such as water and nutrient availability. Among essential nutrients, phosphorus (P) often limits plant productivity because of its low mobility in soil. Therefore, the architecture of the root system may determine the capacity of the plant to acquire this nutrient. We studied the effect of P availability on the development of the root system in Arabidopsis. We found that at P-limiting conditions (<50 μm), the Arabidopsis root system undergoes major architectural changes in terms of lateral root number, lateral root density, and primary root length. Treatment with auxins and auxin antagonists indicate that these changes are related to an increase in auxin sensitivity in the roots of P-deprived Arabidopsis seedlings. It was also found that the axr1-3, axr2-1, and axr4-1 Arabidopsis mutants have normal responses to low P availability conditions, whereas the iaa28-1 mutant shows resistance to the stimulatory effects of low P on root hair and lateral root formation. Analysis of ethylene signaling mutants and treatments with 1-aminocyclopropane-1-carboxylic acid showed that ethylene does not promote lateral root formation under P deprivation. These results suggest that in Arabidopsis, auxin sensitivity may play a fundamental role in the modifications of root architecture by P availability. PMID:12011355

Ectopic expression of R3 MYB transcription factor gene OsTCL1 in Arabidopsis, but not rice, affects trichome and root hair formation

PubMed Central

Zheng, Kaijie; Tian, Hainan; Hu, Qingnan; Guo, Hongyan; Yang, Li; Cai, Ling; Wang, Xutong; Liu, Bao; Wang, Shucai

2016-01-01

In Arabidopsis, a MYB-bHLH-WD40 (MBW) transcriptional activator complex activates the homeodomain protein gene GLABRA2 (GL2), leading to the promotion of trichome formation and inhibition of root hair formation. The same MBW complex also activates single-repeat R3 MYB genes. R3 MYBs in turn, play a negative feedback role by competing with R2R3 MYB proteins for binding bHLH proteins, thus blocking the formation of the MBW complex. By BLASTing the rice (Oryza sativa) protein database using the entire amino acid sequence of Arabidopsis R3 MYB transcription factor TRICHOMELESS1 (TCL1), we found that there are two genes in rice genome encoding R3 MYB transcription factors, namely Oryza sativa TRICHOMELESS1 (OsTCL1) and OsTCL2. Expressing OsTCL1 in Arabidopsis inhibited trichome formation and promoted root hair formation, and OsTCL1 interacted with GL3 when tested in Arabidopsis protoplasts. Consistent with these observations, expression levels of GL2, R2R3 MYB transcription factor gene GLABRA1 (GL1) and several R3 MYB genes were greatly reduced, indicating that OsTCL1 is functional R3 MYB. However, trichome and root hair formation in transgenic rice plants overexpressing OsTCL1 remained largely unchanged, and elevated expression of OsGL2 was observed in the transgenic rice plants, indicating that rice may use different mechanisms to regulate trichome formation. PMID:26758286

CsSCL1 is differentially regulated upon maturation in chestnut microshoots and is specifically expressed in rooting-competent cells.

PubMed

Vielba, Jesús M; Díaz-Sala, Carmen; Ferro, Enrique; Rico, Saleta; Lamprecht, María; Abarca, Dolores; Ballester, Antonio; Sánchez, Conchi

2011-10-01

The Castanea sativa SCL1 gene (CsSCL1) has previously been shown to be induced by auxin during adventitious root (AR) formation in rooting-competent microshoots. However, its expression has not previously been analyzed in rooting-incompetent shoots. This study focuses on the regulation of CsSCL1 during maturation and the role of the gene in the formation of AR. The expression of CsSCL1 in rooting-incompetent microshoots and other tissues was investigated by quantitative reverse transcriptase--polymerase chain reaction. The analysis was complemented by in situ hybridization of the basal segments of rooting-competent and --incompetent microshoots during AR induction, as well as in AR and lateral roots. It was found that CsSCL1 is upregulated by auxin in a cell-type- and phase-dependent manner during the induction of AR. In root-forming shoots, CsSCL1 mRNA was specifically located in the cambial zone and derivative cells, which are rooting-competent cells, whereas in rooting-incompetent shoots the hybridization signal was more diffuse and evenly distributed through the phloem and parenchyma. CsSCL1 expression was also detected in lateral roots and axillary buds. The different CsSCL1 expression patterns in rooting-competent and -incompetent microshoots, together with the specific location of transcripts in cell types involved in root meristem initiation and in the root primordia of AR and lateral roots, indicate an important role for the gene in determining whether certain cells will enter the root differentiation pathway and its involvement in meristem maintenance.

iTRAQ-Based Proteomic Analysis Reveals Potential Regulation Networks of IBA-Induced Adventitious Root Formation in Apple

PubMed Central

Lei, Chao; Fan, Sheng; Li, Ke; Meng, Yuan; Mao, Jiangping; Han, Mingyu; Zhao, Caiping; Bao, Lu; Zhang, Dong

2018-01-01

Adventitious root (AR) formation, which is controlled by endogenous and environmental factors, is indispensable for vegetative asexual propagation. However, comprehensive proteomic data on AR formation are still lacking. The aim of this work was to study indole-3-butyric acid (IBA)-induced AR formation in the dwarf apple rootstock ‘T337’. In this study, the effect of IBA on AR formation was analysed. Subsequent to treatment with IBA, both the rooting rate and root length of ‘T337’ increased significantly. An assessment of hormone levels in basal stem cuttings suggested that auxin, abscisic acid, and brassinolide were higher in basal stem cuttings that received the exogenous IBA application; while zeatin riboside, gibberellins, and jasmonic acid were lower than non-treated basal stem cuttings. To explore the underlying molecular mechanism, an isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic technique was employed to identify the expression profiles of proteins at a key period of adventitious root induction (three days after IBA treatment). In total, 3355 differentially expressed proteins (DEPs) were identified. Many DEPs were closely related to carbohydrate metabolism and energy production, protein homeostasis, reactive oxygen and nitric oxide signaling, and cell wall remodeling biological processes; as well as the phytohormone signaling, which was the most critical process in response to IBA treatment. Further, RT-qPCR analysis was used to evaluate the expression level of nine genes that are involved in phytohormone signaling and their transcriptional levels were mostly in accordance with the protein patterns. Finally, a putative work model was proposed. Our study establishes a foundation for further research and sheds light on IBA-mediated AR formation in apple as well as other fruit rootstock cuttings. PMID:29495482

Petunia as model for elucidating adventitious root formation and mycorrhizal symbiosis: at the nexus of physiology, genetics, microbiology and horticulture.

PubMed

Druege, Uwe; Franken, Philipp

2018-05-17

Adventitious root formation in cuttings and establishment of arbuscular mycorrhizal symbiosis reflect the enormous plasticity of plants and are key factors in the efficient and sustainable clonal propagation and production of ornamental crops. Based on the high importance of Petunia hybrida for the European and US annual bedding plant markets and its suitability as a model for basic plant sciences, petunia has been established as an experimental system for elucidating the molecular and physiological processes underlying adventitious root formation and mycorrhizal symbiosis. In the present review, we introduce the tools of the Petunia model system. Then, we discuss findings regarding the hormonal and metabolic control of adventitious rooting in the context of diverse environmental factors as well as findings on the function of arbuscular mycorrhiza related to nutrient uptake and resistance to root pathogens. Considering the recent publication of the genomes of the parental species of P. hybrida and other tools available in the petunia scientific community, we will outline the quality of petunia as a model for future system-oriented analysis of root development and function in the context of environmental and genetic control, which are at the heart of modern horticulture. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays).

PubMed

Hu, Bo; Henry, Amelia; Brown, Kathleen M; Lynch, Jonathan P

2014-01-01

Formation of root cortical aerenchyma (RCA) can be induced by nutrient deficiency. In species adapted to aerobic soil conditions, this response is adaptive by reducing root maintenance requirements, thereby permitting greater soil exploration. One trade-off of RCA formation may be reduced radial transport of nutrients due to reduction in living cortical tissue. To test this hypothesis, radial nutrient transport in intact roots of maize (Zea mays) was investigated in two radiolabelling experiments employing genotypes with contrasting RCA. In the first experiment, time-course dynamics of phosphate loading into the xylem were measured from excised nodal roots that varied in RCA formation. In the second experiment, uptake of phosphate, calcium and sulphate was measured in seminal roots of intact young plants in which variation in RCA was induced by treatments altering ethylene action or genetic differences. In each of three paired genotype comparisons, the rate of phosphate exudation of high-RCA genotypes was significantly less than that of low-RCA genotypes. In the second experiment, radial nutrient transport of phosphate and calcium was negatively correlated with the extent of RCA for some genotypes. The results support the hypothesis that RCA can reduce radial transport of some nutrients in some genotypes, which could be an important trade-off of this trait.

High-efficiency Agrobacterium rhizogenes-mediated transformation of heat inducible sHSP18.2-GUS in Nicotiana tabacum.

PubMed

Chen, Shih-Cheng; Liu, Hui-Wen; Lee, Kung-Ta; Yamakawa, Takashi

2007-01-01

The chimerical gene, Arabidopsis thaliana sHSP18.2 promoter fused to E. coli gusA gene, was Agrobacterium rhizogenes-mediated transformed into Nicotiana tabacum as a heat-regulatable model, and the thermo-inducible expression of GUS activity in N. tabacum transgenic hairy roots was profiled. An activation of A. rhizogenes with acetosyringone (AS) before cocultured with tobacco's leaf disc strongly promoted transgenic hairy roots formation. Transgenic hairy roots formation efficiency of A. rhizogenes precultured with 200 microM AS supplementation was 3.1-fold and 7.5-fold, respectively, compared to the formation efficiency obtained with and without AS supplementation in coculture. Transgenic hairy roots transformed with different AS concentration exhibited a similar pattern of thermo-inducibility after 10 min to 3 h heat treatments detected by GUS expression. The peak of expressed GUS specific activity, 399,530 pmol MUG per mg total protein per min, of the transgenic hairy roots was observed at 48 h after 3 h of 42 degrees C heat treatment, and the expressed GUS specific activity was 7-26 times more than that reported in A. thaliana, tobacco BY-2 cells and Nicotiana plumbaginifolia. Interference caused by AS supplementation on the growth of transgenic hairy roots, time-course of GUS expression and its expression level were not observed.

Polymorphisms in the AOX2 gene are associated with the rooting ability of olive cuttings.

PubMed

Hedayati, Vahideh; Mousavi, Amir; Razavi, Khadijeh; Cultrera, Nicolò; Alagna, Fiammetta; Mariotti, Roberto; Hosseini-Mazinani, Mehdi; Baldoni, Luciana

2015-07-01

Different rooting ability candidate genes were tested on an olive cross progeny. Our results demonstrated that only the AOX2 gene was strongly induced. OeAOX2 was fully characterised and correlated to phenotypical traits. The formation of adventitious roots is a key step in the vegetative propagation of trees crop species, and this ability is under strict genetic control. While numerous studies have been carried out to identify genes controlling adventitious root formation, only a few loci have been characterised. In this work, candidate genes that were putatively involved in rooting ability were identified in olive (Olea europaea L.) by similarity with orthologs identified in other plant species. The mRNA levels of these genes were analysed by real-time PCR during root induction in high- (HR) and low-rooting (LR) individuals. Interestingly, alternative oxidase 2 (AOX2), which was previously reported to be a functional marker for rooting in olive cuttings, showed a strong induction in HR individuals. From the OeAOX2 full-length gene, alleles and effective polymorphisms were distinguished and analysed in the cross progeny, which were segregated based on rooting. The results revealed a possible correlation between two single nucleotide polymorphisms of OeAOX2 gene and rooting ability.

Biochemical and molecular characterization of rice (Oryza sativa L.) roots forming a barrier to radial oxygen loss.

PubMed

Kulichikhin, Konstantin; Yamauchi, Takaki; Watanabe, Kohtaro; Nakazono, Mikio

2014-10-01

The formation of a barrier to radial oxygen (O2 ) loss (ROL) in the root is an important adaptation of plants to root flooding, but the biochemical changes in plant roots where the barrier is formed are unclear. In this study, we analysed metabolic profiles and gene expression profiles in roots of rice (Oryza sativa L.) plants grown under stagnant deoxygenated conditions, which induce suberization in the outer cell layers of the roots and formation of barrier to ROL. Under these conditions, two distinctive biochemical features of the roots were the accumulations of malic acid and very long chain fatty acids (VLCFAs). We also showed that the expressions of some genes encoding plastid-localized enzymes, which convert malic acid to acetyl coenzyme A (AcCoA), were simultaneously up-regulated under stagnant conditions. The expression levels of these genes in specific root tissues isolated by laser microdissection suggested that malic acid is converted to AcCoA predominantly in the plastids in the outer cell layers of rice roots. We propose that the physiological role of malic acid accumulation in rice roots grown under stagnant conditions is to provide a substrate for the biosynthesis of fatty acids, which, in turn, are used in the biosynthesis of suberin. © 2014 John Wiley & Sons Ltd.

A Formate Dehydrogenase Confers Tolerance to Aluminum and Low pH1[OPEN

PubMed Central

Gong, Yu Long; Fan, Wei; Xu, Jia Meng; Liu, Yu; Cao, Meng Jie; Wang, Ming-Hu

2016-01-01

Formate dehydrogenase (FDH) is involved in various higher plant abiotic stress responses. Here, we investigated the role of rice bean (Vigna umbellata) VuFDH in Al and low pH (H+) tolerance. Screening of various potential substrates for the VuFDH protein demonstrated that it functions as a formate dehydrogenase. Quantitative reverse transcription-PCR and histochemical analysis showed that the expression of VuFDH is induced in rice bean root tips by Al or H+ stresses. Fluorescence microscopic observation of VuFDH-GFP in transgenic Arabidopsis plants indicated that VuFDH is localized in the mitochondria. Accumulation of formate is induced by Al and H+ stress in rice bean root tips, and exogenous application of formate increases internal formate content that results in the inhibition of root elongation and induction of VuFDH expression, suggesting that formate accumulation is involved in both H+- and Al-induced root growth inhibition. Over-expression of VuFDH in tobacco (Nicotiana tabacum) results in decreased sensitivity to Al and H+ stress due to less production of formate in the transgenic tobacco lines under Al and H+ stresses. Moreover, NtMATE and NtALS3 expression showed no changes versus wild type in these over-expression lines, suggesting that herein known Al-resistant mechanisms are not involved. Thus, the increased Al tolerance of VuFDH over-expression lines is likely attributable to their decreased Al-induced formate production. Taken together, our findings advance understanding of higher plant Al toxicity mechanisms, and suggest a possible new route toward the improvement of plant performance in acidic soils, where Al toxicity and H+ stress coexist. PMID:27021188

Development of the foremost light-curable calcium-silicate MTA cement as root-end in oral surgery. Chemical-physical properties, bioactivity and biological behavior.

PubMed

Gandolfi, Maria Giovanna; Taddei, Paola; Siboni, Francesco; Modena, Enrico; Ciapetti, Gabriela; Prati, Carlo

2011-07-01

An innovative light-curable calcium-silicate cement containing a HEMA-TEGDMA-based resin (lc-MTA) was designed to obtain a bioactive fast setting root-end filling and root repair material. lc-MTA was tested for setting time, solubility, water absorption, calcium release, alkalinizing activity (pH of soaking water), bioactivity (apatite-forming ability) and cell growth-proliferation. The apatite-forming ability was investigated by micro-Raman, ATR-FTIR and ESEM/EDX after immersion at 37°C for 1-28 days in DPBS or DMEM+FBS. The marginal adaptation of cement in root-end cavities of extracted teeth was assessed by ESEM/EDX, and the viability of Saos-2 cell on cements was evaluated. lc-MTA demonstrated a rapid setting time (2min), low solubility, high calcium release (150-200ppm) and alkalinizing power (pH 10-12). lc-MTA proved the formation of bone-like apatite spherulites just after 1 day. Apatite precipitates completely filled the interface porosities and created a perfect marginal adaptation. lc-MTA allowed Saos-2 cell viability and growth and no compromising toxicity was exerted. HEMA-TEGDMA creates a polymeric network able to stabilize the outer surface of the cement and a hydrophilic matrix permeable enough to allow water absorption. SiO(-)/Si-OH groups from the mineral particles induce heterogeneous nucleation of apatite by sorption of calcium and phosphate ions. Oxygen-containing groups from poly-HEMA-TEGDMA provide additional apatite nucleating sites through the formation of calcium chelates. The strong novelty was that the combination of a hydraulic calcium-silicate powder and a poly-HEMA-TEGDMA hydrophilic resin creates the conditions (calcium release and functional groups able to chelate Ca ions) for a bioactive fast setting light-curable material for clinical applications in dental and maxillofacial surgery. The first and unique/exclusive light-curable calcium-silicate MTA cement for endodontics and root-end application was created, with a potential strong impact on surgical procedures. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Parallel evolution of storage roots in morning glories (Convolvulaceae).

PubMed

Eserman, Lauren A; Jarret, Robert L; Leebens-Mack, James H

2018-05-29

Storage roots are an ecologically and agriculturally important plant trait that have evolved numerous times in angiosperms. Storage roots primarily function to store carbohydrates underground as reserves for perennial species. In morning glories, storage roots are well characterized in the crop species sweetpotato, where starch accumulates in storage roots. This starch-storage tissue proliferates, and roots thicken to accommodate the additional tissue. In morning glories, storage roots have evolved numerous times. The primary goal of this study is to understand whether this was through parallel evolution, where species use a common genetic mechanism to achieve storage root formation, or through convergent evolution, where storage roots in distantly related species are formed using a different set of genes. Pairs of species where one forms storage roots and the other does not were sampled from two tribes in the morning glory family, the Ipomoeeae and Merremieae. Root anatomy in storage roots and fine roots was examined. Furthermore, we sequenced total mRNA from storage roots and fine roots in these species and analyzed differential gene expression. Anatomical results reveal that storage roots of species in the Ipomoeeae tribe, such as sweetpotato, accumulate starch similar to species in the Merremieae tribe but differ in vascular tissue organization. In both storage root forming species, more genes were found to be upregulated in storage roots compared to fine roots. Further, we find that fifty-seven orthologous genes were differentially expressed between storage roots and fine roots in both storage root forming species. These genes are primarily involved in starch biosynthesis, regulation of starch biosynthesis, and transcription factor activity. Taken together, these results demonstrate that storage roots of species from both morning glory tribes are anatomically different but utilize a common core set of genes in storage root formation. This is consistent with a pattern of parallel evolution, thus highlighting the importance of examining anatomy together with gene expression to understand the evolutionary origins of ecologically and economically important plant traits.

Nitric oxide is involved in hydrogen gas-induced cell cycle activation during adventitious root formation in cucumber.

PubMed

Zhu, Yongchao; Liao, Weibiao; Niu, Lijuan; Wang, Meng; Ma, Zhanjun

2016-06-28

Adventitious root development is a complex process regulated through a variety of signaling molecules. Hydrogen gas (H2) and nitric oxide (NO), two new signaling molecules are both involved in plant development and stress tolerance. To investigate the mechanism of adventitious root development induced by hydrogen-rich water (HRW), a combination of fluorescence microscopy and molecular approaches was used to study cell cycle activation and cell cycle-related gene expression in cucumber (Cucumis sativus 'Xinchun 4') explants. The results revealed that the effect of HRW on adventitious root development was dose-dependent, with maximal biological responses at 50 % HRW. HRW treatment increased NO content in a time-dependent fashion. The results also indicated that HRW and NO promoted the G1-to-S transition and up-regulated cell cycle-related genes: CycA (A-type cyclin), CycB (B-type cyclin), CDKA (cyclin-dependent kinase A) and CDKB (cyclin-dependent kinase B) expression. Additionally, target genes related to adventitious rooting were up-regulated by HRW and NO in cucumber explants. While, the responses of HRW-induced adventitious root development and increase of NO content were partially blocked by a specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt, NO synthase (NOS)-like enzyme inhibitor N(G) -nitro-L-arginine methylester hydrochloride, or nitrate reductase inhibitors tungstate and NaN3. These chemicals also partially reversed the effect of HRW on cell cycle activation and the transcripts of cell cycle regulatory genes and target genes related adventitious root formation. Together, NO may emerge as a downstream signaling molecule in H2-induced adventitious root organogenesis. Additionally, H2 mediated cell cycle activation via NO pathway during adventitious root formation.

[Influences of arbuscular mycorrhizal fungus and phosphorus level on the lateral root formation of tomato seedlings].

PubMed

Jiang, Xia; Chen, Wei-li; Xu, Chun-xiang; Zhu, Hong-hui; Yao, Qing

2015-04-01

To explore the influences of arbuscular mycorrhizal fungi (AMF) and P level on plant root system architecture, tomato seedlings were inoculated with AMF strain Rhizophagus irregularis BGC JX04B under two P levels, and the influences of AMF and P level on lateral root (LR) formation of tomato seedlings were studied. Results indicated that the promoting effect of AMF on plant biomass was not evident, but significantly decreased the root to shoot ratio of plants. AMF significantly increased the primary root length but decreased the 1st order LR length and interacted with the mycorrhizal colonization period. AMF significantly lowered the 2nd-3rd order LR number and the ratio of 2nd order LR number to 1st order LR number, but did not significantly affect the 1st-2nd order LR density. High P level (50 mg x kg(-1) P) significantly promoted the plant growth and decreased the root to shoot ratio of plants. It had no significant effect on the primary root length and the 1st order root length, but significantly enhanced the 1st-3rd order LR number and the ratio of 2nd order LR number to P order LR number, increased the 1st-2nd order LR density. It suggested that AMF and P level did not share a common mechanism to influence the LR formation of tomato plants. The influence of high P level may depend on its promoting effects on nutrient uptake and plant growth, while the influence of AMF is more complex. Furthermore, the interaction between AMF and mycorrhizal colonization period implies the possible involvement of carbohydrate distribution (sugar signaling) in the regulation of root system architecture by AMF.

Cambial Activity and Intra-annual Xylem Formation in Roots and Stems of Abies balsamea and Picea mariana

PubMed Central

Thibeault-Martel, Maxime; Krause, Cornelia; Morin, Hubert; Rossi, Sergio

2008-01-01

Background and Aims Studies on xylogenesis focus essentially on the stem, whereas there is basically no information about the intra-annual growth of other parts of the tree. As roots strongly influence carbon allocation and tree development, knowledge of the dynamics of xylem production and maturation in roots at a short time scale is required for a better understanding of the phenomenon of tree growth. This study compared cambial activity and xylem formation in stem and roots in two conifers of the boreal forest in Canada. Methods Wood microcores were collected weekly in stem and roots of ten Abies balsamea and ten Picea mariana during the 2004–2006 growing seasons. Cross-sections were cut using a rotary microtome, stained with cresyl violet acetate and observed under visible and polarized light. The number of cells in the cambial zone and in differentiation, plus the number of mature cells, was counted along the developing xylem. Key Results Xylem formation lasted from the end of May to the end of September, with no difference between stem and roots in 2004–2005. On the contrary, in 2006 a 1-week earlier beginning of cell differentiation was observed in the stem, with cell wall thickening and lignification in roots ending up to 22 d later than in the stem. Cell production in the stem was concentrated early in the season, in June, while most cell divisions in roots occurred 1 month later. Conclusions The intra-annual dynamics of growth observed in stem and roots could be related to the different amount of cells produced by the cambium and the patterns of air and soil temperature occurring in spring. PMID:18708643

An analysis of root cause identification and continuous quality improvement in public health H1N1 after-action reports.

PubMed

Singleton, Christa-Marie; Debastiani, Summer; Rose, Dale; Kahn, Emily B

2014-01-01

To identify the extent to which the Homeland Security Exercise and Evaluation Program's (HSEEP) After Action Report/Improvement Plan (AAR/IP) template was followed by public health entities and facilitated the identification of detailed corrective actions and continuous improvement. Data were drawn from the US H1N1 Public Health Emergency Response (PHER) federal grant awardees (n = 62). After action report/improvement plan text was examined to identify the presence of AAR/IP HSEEP elements and characterized as "minimally complete," "partially complete," or "complete." Corrective actions (CA) and recommendations within the IP focusing on performance deficits were coded as specific, measurable, and time-bound, and whether they were associated with a problem that met root cause criteria and whether the CA/recommendation was intended to address or fix the root cause. A total of 2619 CA/recommendations were identified. More than half (n = 1480, 57%) addressed root causes. Corrective actions/recommendations associated with complete AARs more frequently addressed root cause (58% vs 51%, χ = 9.1, P < 0.003) and were more specific (34% vs 23%, χ = 32.3, P < 0.0001), measurable (30% vs 18%, χ = 37.9, P < 0.0001), and time-bound (38% vs 15%, χ = 115.5, P < 0.0001) than partially complete AARs. The same pattern was not observed with completeness of IPs. Corrective actions and recommendations were similarly specific and measurable. Recommendations significantly addressed root cause more than CAs. Our analysis indicates a possible lack of awardee distinction between CA and recommendations in AARs. As HSEEP adapts to align with the 2011 National Preparedness Goal and National Preparedness System, future HSEEP documents should emphasize the importance of root cause analysis as a required element within AAR documents and templates in the exercise and real incident environment, as well as the need for specific and measurable CAs.

Exploring the structural basis for selenium/mercury antagonism in Allium fistulosum

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNear, Jr., David H.; Afton, Scott E.; Caruso, Joseph A.

While continuing efforts are devoted to studying the mutually protective effect of mercury and selenium in mammals, few studies have investigated the mercury-selenium antagonism in plants. In this study, we report the metabolic fate of mercury and selenium in Allium fistulosum (green onion) after supplementation with sodium selenite and mercuric chloride. Analysis of homogenized root extracts via capillary reversed phase chromatography coupled with inductively coupled plasma mass spectrometry (capRPLC-ICP-MS) suggests the formation of a mercury-selenium containing compound. Micro-focused synchrotron X-ray fluorescence mapping of freshly excised roots show Hg sequestered on the root surface and outlining individual root cells, while Semore » is more evenly distributed throughout the root. There are also discrete Hg-only, Se-only regions and an overall strong correlation between Hg and Se throughout the root. Analysis of the X-ray absorption near edge structure (XANES) spectra show a 'background' of methylselenocysteine within the root with discrete spots of SeO{sub 3}{sup 2-}, Se{sup 0} and solid HgSe on the root surface. Mercury outlining individual root cells is possibly binding to sulfhydryl groups or plasma membrane or cell wall proteins, and in some places reacting with reduced selenium in the rhizosphere to form a mercury(II) selenide species. Together with the formation of the root-bound mercury(II) selenide species, we also report on the formation of cinnabar (HgS) and Hg{sup 0} in the rhizosphere. The results presented herein shed light on the intricate chemical and biological processes occurring within the rhizosphere that influence Hg and Se bioavailability and will be instrumental in predicting the fate and assisting in the remediation of these metals in the environment and informing whether or not fruit and vegetable food selection from aerial plant compartments or roots from plants grown in Hg contaminated soils, are safe for consumption.« less

In situ ∼2.0 Ma trees discovered as fossil rooted stumps, lowermost Bed I, Olduvai Gorge, Tanzania.

PubMed

Habermann, Jörg M; Stanistreet, Ian G; Stollhofen, Harald; Albert, Rosa M; Bamford, Marion K; Pante, Michael C; Njau, Jackson K; Masao, Fidelis T

2016-01-01

The discovery of fossil rooted tree stumps in lowermost Lower Bed I from the western Olduvai Basin, Tanzania, age-bracketed by the Naabi Ignimbrite (2.038 ± 0.005 Ma) and Tuff IA (1.88 ± 0.05 Ma), provides the first direct, in situ, and to date oldest evidence of living trees at Olduvai Gorge. The tree relicts occur in an interval dominated by low-viscosity mass flow and braided fluvial sediments, deposited at the toe of a largely Ngorongoro Volcano-sourced volcaniclastic fan apron that comprised a widely spaced network of ephemeral braided streams draining northward into the Olduvai Basin. Preservation of the trees occurred through their engulfment by mass flows, post-mortem mold formation resulting from differential decay of woody tissues, and subsequent fluvially-related sediment infill, calcite precipitation, and cast formation. Rhizolith preservation was triggered by the interaction of root-induced organic and inorganic processes to form rhizocretionary calcareous root casts. Phytolith analyses were carried out to complete the paleoenvironmental reconstruction. They imply a pronounced seasonality and indicate a wooded landscape with grasses, shrubs, and sedges growing nearby, comparable to the low, open riverine woodland (unit 4c) along the Garusi River and tributaries in the Laetoli area. Among the tree stump cluster were found outsized lithic clasts and those consisting of quartzite were identified as Oldowan stone tool artifacts. In the context of hominin activity, the identification of wooded grassland in association with nearby freshwater drainages and Oldowan artifacts significantly extends our paleoenvironmental purview on the basal parts of Lower Bed I, and highlights the hitherto underrated role of the yet poorly explored western Olduvai Gorge area as a potential ecologically attractive setting and habitat for early hominins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of Blood Cell Attachment on Er:Yag Laser Applied Root Surface Using Scanning Electron Microscopy

PubMed Central

CEKICI, Ali; MADEN, Ilay; YILDIZ, Sercan; SAN, Tangul; ISIK, Gulden

2013-01-01

Background: Periodontal regeneration is dependent on the uninterrupted adhesion, maturation and absorption of fibrin clots to a periodontally compromised root surface. The modification of the root surface with different agents has been used for better fibrin clot formation and blood cell attachment. It is known that Er:YAG laser application on dentin removes the smear layer succesfully. Aim: The aim of this study is to observe blood cell attachment and fibrin network formation following ER:YAG laser irradiation on periodontally compromised root surfaces in comparison to chemical root conditioning techniques in vitro. Materials and methods: 40 dentin blocks prepared from freshly extracted periodontally compromised hopeless teeth. Specimens were divided in 5 groups; those applied with PBS, EDTA, Citric acid and Er:YAG. They were further divided into two groups: those which had received these applications, and the control group. The specimens were evaluated with scanning electron microscope and micrographs were taken. Smear layer and blood cell attachment scoring was performed. Results: In the Er:YAG laser applied group, smear layer were totally removed. In the blood applied specimens, better fibrin clot formation and blood cell attachment were observed in the Er:YAG group. In the group that had been applied with citric acid, the smear layer was also removed. The smear layer could not be fully removed in the EDTA group. Conclusion: Er:YAG laser application on the root dentin seems to form a suitable surface for fibrin clot formation and blood cell attachment. Further clinical studies to support these results are necessitated. PMID:23533017

The Ethylene Responsive Factor Required for Nodulation 1 (ERN1) Transcription Factor Is Required for Infection-Thread Formation in Lotus japonicus.

PubMed

Kawaharada, Yasuyuki; James, Euan K; Kelly, Simon; Sandal, Niels; Stougaard, Jens

2017-03-01

Several hundred genes are transcriptionally regulated during infection-thread formation and development of nitrogen-fixing root nodules. We have characterized a set of Lotus japonicus mutants impaired in root-nodule formation and found that the causative gene, Ern1, encodes a protein with a characteristic APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription-factor domain. Phenotypic characterization of four ern1 alleles shows that infection pockets are formed but root-hair infection threads are absent. Formation of root-nodule primordia is delayed and no normal transcellular infection threads are found in the infected nodules. Corroborating the role of ERN1 (ERF Required for Nodulation1) in nodule organogenesis, spontaneous nodulation induced by an autoactive CCaMK and cytokinin-induced nodule primordia were not observed in ern1 mutants. Expression of Ern1 is induced in the susceptible zone by Nod factor treatment or rhizobial inoculation. At the cellular level, the pErn1:GUS reporter is highly expressed in root epidermal cells of the susceptible zone and in the cortical cells that form nodule primordia. The genetic regulation of this cellular expression pattern was further investigated in symbiotic mutants. Nod factor induction of Ern1 in epidermal cells was found to depend on Nfr1, Cyclops, and Nsp2 but was independent of Nin and Nf-ya1. These results suggest that ERN1 functions as a transcriptional regulator involved in the formation of infection threads and development of nodule primordia and may coordinate these two processes.

Patient Demonstration Videos in Predoctoral Endodontic Education: Aspects Perceived as Beneficial by Students.

PubMed

Edrees, Hadeel Y; Ohlin, Johan; Ahlquist, Michael; Tessma, Mesfin K; Zary, Nabil

2015-08-01

The aim of this study was to assess the perceived benefits of video-mediated demonstrations in learning endodontics. Participants in the study were 75 third-year students enrolled in the undergraduate dentistry program at Karolinska Institute, Stockholm, Sweden. After the endodontic preclinical course, the students were introduced to the treatment protocol in the clinic by watching two live patient-demonstrated videos. The first video demonstrated how to communicate with the patient and perform diagnosis and root canal instrumentation. The second video illustrated how to perform bacterial sampling and root canal filling. After the students watched each video, a questionnaire was used to evaluate their opinions about various steps of the endodontic treatment protocol and the benefit of such educational material for their practice. Of the total 75 students, 72 completed the first questionnaire (96% response rate), and 65 completed the second questionnaire (87% response rate). The results showed that the students perceived high value in the video demonstrations related to treatment procedure. A statistically significant difference was observed between the perceived benefits of the first and second sessions in communication and treatment procedure (p<0.001). Further studies are needed to assess improvement in the design and delivery format for video demonstrations to enhance their effectiveness as a teaching modality for endodontics.

Use of third molar transplantation for closure of the oroantral communication after tooth extraction: a report of 2 cases.

PubMed

Kitagawa, Yoshimasa; Sano, Kazuo; Nakamura, Mikiko; Ogasawara, Toshiyuki

2003-04-01

This clinical report introduces a promising and unique method for the immediate closure of the oroantral communication (OAC) after tooth extraction: the use of the transplanted third molar with closed apices. In 2 adult patients, OAC caused by the extraction of an upper molar was immediately closed by using a transplanted third molar with complete root formation. After tooth extraction at the recipient site, OAC with perforated mucosa of the sinus floor was confirmed and the donor third molar was transferred to the prepared recipient socket. Endodontic therapy of the transplanted third molar began at 3 weeks after surgery, and prosthetic treatment was completed at 5 months after the operation. These 2 patients were carefully observed both clinically and radiographically. Closure of the OAC was successfully performed, and the transplanted teeth became fixed with the passage of time in these 2 patients. Root resorption did not occur, and good functional results were obtained without any complications. Tooth transplantation of a mature third molar for closure of the OAC is a simple and excellent method because the transplanted tooth not only closes the communication to the maxillary sinus, but it also satisfactorily functions at the recipient site during mastication, even in adult patients.

Aluminum stress increases carbon-centered radicals in soybean roots.

PubMed

Abo, Mitsuru; Yonehara, Hiroki; Yoshimura, Etsuro

2010-10-15

The formation of radical species was examined in roots of soybean seedlings exposed to aluminum (Al). Electron spin resonance (ESR) spectra of root homogenates with the spin-trapping reagent 5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO) indicated the presence of carbon-centered radicals in plants not exposed to Al. Plants exposed to 50 microM Al showed a similar spectrum, with increased signal intensity. These radicals were likely produced through a H-atom abstraction reaction by hydroxyl (*OH) radicals, the synthesis of which was initiated by the formation of superoxide (O2*-) anions. The increased production of the carbon-centered radicals may be responsible for the lipid peroxidation in Al-treated roots. Copyright (c) 2010 Elsevier GmbH. All rights reserved.

Morphological and Physiological Factors Affecting Formation of Adventitious Roots on Sugar Maple Stem Cuttings

Treesearch

John R. Donnelly

1977-01-01

Sugar maple cuttings were collected twice a week throughout June from four mature trees. Some of the cuttings were analyzed for carbohydrate (starch and sugars) and nitrogen content; the others were stuck in rooting beds. Rooting response showed significant daily and clonal variations. Cuttings rooted best when their terminal leaves were mature, as judged by size and...

Characterization of extracellular polymeric substances of Bacillus amyloliquefaciens SQR9 induced by root exudates of cucumber.

PubMed

Kimani, Veronicah Njeri; Chen, Lin; Liu, Yunpeng; Raza, Waseem; Zhang, Nan; Mungai, Lewis Kamau; Shen, Qirong; Zhang, Ruifu

2016-11-01

Bacillus amyloliquefaciens SQR9 is a plant growth-promoting rhizobacterium (PGPRs) that forms biofilm on the roots of plants and protects them from a variety of pathogens. In this study, we reported the effect of root exudates produced by cucumber (Cucumis sativus L.) at different developmental stages on the biochemical composition of the biofilm matrix of SQR9. The results showed that the amino acids present in the root exudates of cucumber were responsible for triggering biofilm formation of SQR9. In addition, when root exudates harvested at different growth phases of cucumber were used as carbon sources for biofilm formation, the resulting biofilm matrixes differed both quantitatively and qualitatively. The biofilm matrix was mostly composed of amino groups observed by confocal laser scanning microscope (CLSM) hence the proteins formed the major component of the resulting extracellular polymeric substances (EPS). The potential use of amino acid-based dietary supplements to control biofilm formation in the plants may be a viable option to improve agricultural productivity by recruiting beneficial association with PGPRs in the manufacture of bio fertilizers or bio controls. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Roles of auxin and ethylene in aerenchyma formation in sugarcane roots.

PubMed

Tavares, E Q P; Grandis, A; Lembke, C G; Souza, G M; Purgatto, E; De Souza, A P; Buckeridge, M S

2018-03-04

Although the cross-talk between auxin and ethylene has been described during plant development, the role played by auxin upon gene expression during aerenchyma formation is poorly understood. Root aerenchyma formation results from the opening of gas spaces in the cortex. It is part of a developmental program (constitutive) or due to ethylene treatment or abiotic stress (induced) such as flooding and nutrient starvation. This process relies on programmed cell death and cell wall modifications. Here we followed development of aerenchyma formation in sugarcane along 5 cm from the root apex. As a constitutive process, the aerenchyma formation was observed in the cortex from the 3 rd cm onwards. This occurred despite 1-methylcyclepropene (1-MCP) treatment, an inhibitor of ethylene perception. However, this process occurred while ethylene (and auxin) levels decreased. Within the aerenchyma formation zone, the concentration of ethylene is lower in comparison to the concentration in maize. Besides, the ratio between both hormones (ethylene and auxin) was around 1:1. These pieces of evidence suggest that ethylene sensitivity and ethylene-auxin balance may play a role in the formation of aerenchyma. Furthermore, the transcriptional analysis showed that genes related to cell expansion are up-regulated due to 1-MCP treatment. Our results help explaining the regulation of the formation constitutive aerenchyma in sugarcane.

A peptide hormone required for Casparian strip diffusion barrier formation in Arabidopsis roots.

PubMed

Nakayama, Takuya; Shinohara, Hidefumi; Tanaka, Mina; Baba, Koki; Ogawa-Ohnishi, Mari; Matsubayashi, Yoshikatsu

2017-01-20

Plants achieve mineral ion homeostasis by means of a hydrophobic barrier on endodermal cells called the Casparian strip, which restricts lateral diffusion of ions between the root vascular bundles and the soil. We identified a family of sulfated peptides required for contiguous Casparian strip formation in Arabidopsis roots. These peptide hormones, which we named Casparian strip integrity factor 1 (CIF1) and CIF2, are expressed in the root stele and specifically bind the endodermis-expressed leucine-rich repeat receptor kinase GASSHO1 (GSO1)/SCHENGEN3 and its homolog, GSO2. A mutant devoid of CIF peptides is defective in ion homeostasis in the xylem. CIF genes are environmentally responsive. Casparian strip regulation is not merely a passive process driven by root developmental cues; it also serves as an active strategy to cope with adverse soil conditions. Copyright © 2017, American Association for the Advancement of Science.

SHR overexpression induces the formation of supernumerary cell layers with cortex cell identity in rice.

PubMed

Henry, S; Dievart, A; Divol, F; Pauluzzi, G; Meynard, D; Swarup, R; Wu, S; Gallagher, K L; Périn, C

2017-05-01

The number of root cortex cell layers varies among plants, and many species have several cortical cell layers. We recently demonstrated that the two rice orthologs of the Arabidopsis SHR gene, OsSHR1 and OsSHR2, could complement the A. thaliana shr mutant. Moreover, OsSHR1 and OsSHR2 expression in A. thaliana roots induced the formation of extra root cortical cell layers. In this article, we demonstrate that the overexpression of AtSHR and OsSHR2 in rice roots leads to plants with wide and short roots that contain a high number of extra cortical cell layers. We hypothesize that SHR genes share a conserved function in the control of cortical cell layer division and the number of ground tissue cell layers in land plants. Copyright © 2017 Elsevier Inc. All rights reserved.

Rooting depths of plants relative to biological and environmental factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foxx, T S; Tierney, G D; Williams, J M

1984-11-01

In 1981 to 1982 an extensive bibliographic study was completed to document rooting depths of native plants in the United States. The data base presently contains 1034 citations with approximately 12,000 data elements. In this paper the data were analyzed for rooting depths as related to life form, soil type, geographical region, root type, family, root depth to shoot height ratios, and root depth to root lateral ratios. Average rooting depth and rooting frequencies were determined and related to present low-level waste site maintenance.

Peroxidases, lignin and anatomy during in vitro and ex vitro rooting of gardenia (Gardenia jasminoides Ellis) microshoots.

PubMed

Hatzilazarou, Stefanos P; Syros, Thomas D; Yupsanis, Traianos A; Bosabalidis, Artemios M; Economou, Athanasios S

2006-07-01

In vitro and ex vitro rooting of gardenia (Gardenia jasminoides Ellis) microshoots with or without indolic-3-butyric acid (IBA) was studied in order to improve acclimatization of microplants after root formation and transplantation. Peroxidase (POD) activity and isoforms, lignin content and anatomical observations were evaluated in the course of the three interdependent phases (induction, initiation and expression) of microshoot rooting. Microshoots treated or not treated with IBA achieved high rooting percentages both in vitro and ex vitro. At the end of the 2-week acclimatization period, the percentage of surviving microplants ranged from 80% to 100%, for in vitro and ex vitro rooted microshoots, respectively. Microshoots rooted in vitro and ex vitro showed a relationship between rooting and POD activity but in a different time course. It appeared that root formation occurred after the microshoots had reached and passed a peak of maximum enzyme activity. In all treatments, electrophoretic analysis (native PAGE) of PODs revealed the appearance of one anionic and three cationic POD isoforms (C(1), C(3) and C(4)). An additional cationic POD isoform (C(2)) appeared only in the ex vitro rooting. The lignin content was similar in microshoots rooted both in vitro and ex vitro. The sequential anatomical changes during the rooting process were similar in both in vitro and ex vitro rooting treatments. In the case of in vitro rooting, pith cells had vacuoles entirely filled with a dark substance, while in the case of ex vitro rooting, pith cells contained many amyloplasts. The origin of the adventitious roots, in both rooting conditions, was located in the cambial ring. Roots with organized tissue systems emerged from the microshoot stem 10-14 days after the root induction treatments; on day 10 for rooting in vitro, while a 4-day delay was noted in microshoots rooted ex vitro.

Superior Root Hair Formation Confers Root Efficiency in Some, But Not All, Rice Genotypes upon P Deficiency.

PubMed

Nestler, Josefine; Wissuwa, Matthias

2016-01-01

Root hairs are a low-cost way to extend root surface area (RSA), water and nutrient acquisition. This study investigated to what extend variation exists for root hair formation in rice in dependence of genotype, phosphorus (P) supply, growth medium, and root type. In general, genotypic variation was found for three root hair properties: root hair length, density, and longevity. In low P nutrient solution more than twofold genotypic difference was detected for root hair length while only onefold variation was found in low P soil. These differences were mostly due to the ability of some genotypes to increase root hair length in response to P deficiency. In addition, we were able to show that a higher proportion of root hairs remain viable even in mature, field-grown plants under low P conditions. All investigated root hair parameters exhibited high correlations across root types which were always higher in the low P conditions compared to the high P controls. Therefore we hypothesize that a low P response leads to a systemic signal in the entire root system. The genotype DJ123 consistently had the longest root hairs under low P conditions and we estimated that, across the field-grown root system, root hairs increased the total RSA by 31% in this genotype. This would explain why DJ123 is considered to be very root efficient in P uptake and suggests that DJ123 should be utilized as a donor in breeding for enhanced P uptake. Surprisingly, another root and P efficient genotype seemed not to rely on root hair growth upon P deficiency and therefore must contain different methods of low P adaptation. Genotypic ranking of root hair properties did change substantially with growth condition highlighting the need to phenotype plants in soil-based conditions or at least to validate results obtained in solution-based growth conditions.

Biomechanical consequences of a complete radial tear adjacent to the medial meniscus posterior root attachment site: in situ pull-out repair restores derangement of joint mechanics.

PubMed

Padalecki, Jeffrey R; Jansson, Kyle S; Smith, Sean D; Dornan, Grant J; Pierce, Casey M; Wijdicks, Coen A; Laprade, Robert F

2014-03-01

Complete radial tears near the medial meniscus posterior root attachment site disrupt the circumferential integrity of the meniscus (similar to a posterior root avulsion). These tears can compromise the circumferential integrity, and they have been reported in biomechanical studies to be comparable with the meniscectomized state. To quantify the tibiofemoral contact pressure and contact area changes that occur in cadaveric knees from complete posterior horn radial tears and subsequent repairs of the medial meniscus adjacent to the posterior root attachment site. Controlled laboratory study. Six nonpaired fresh-frozen human cadaveric knees each underwent 45 different testing conditions: 9 medial meniscus conditions (intact, root avulsion, root repair, serial radial tear at 3, 6, and 9 mm from the root attachment site, and in situ repair at the same 3 distances from the root attachment site) at 5 flexion angles (0°, 30°, 45°, 60°, and 90°), under a 1000-N axial load. Tekscan sensors were used to measure contact area and pressure in the medial and lateral compartments. The medial meniscus root avulsion and all radial tear conditions resulted in significantly decreased contact area and increased mean contact pressure compared with the intact state for knee flexion angles beyond 0° (P < .05). The root repair and in situ repairs restored contact area and pressure to levels statistically indistinguishable from those of the intact meniscus and increased contact area and decreased contact pressure compared with the corresponding tear conditions. Posterior horn radial tears adjacent to the medial meniscus root that extend to the meniscocapsular junction can lead to derangement of the loading profiles of the medial compartment that are similar to a root avulsion. Repair of these radial tears with an in situ pull-out technique restored joint mechanics to the intact state. Complete radial tears of the posterior horn of the medial meniscus, which occur relatively frequently, are biomechanically equivalent to root avulsions and could potentially lead to medial compartment arthrosis. An in situ repair offers an alternative treatment to meniscectomy and can reestablish the posterior anchor point, thus improving load distribution in the medial compartment. Future clinical studies of these repairs are recommended.

Enhanced rhizosphere colonization of beneficial Bacillus amyloliquefaciens SQR9 by pathogen infection.

PubMed

Liu, Yunpeng; Zhang, Nan; Qiu, Meihua; Feng, Haichao; Vivanco, Jorge M; Shen, Qirong; Zhang, Ruifu

2014-04-01

Root exudates play important roles in root-soil microorganism interactions and can mediate tripartite interactions of beneficial microorganisms-plant-pathogen in the rhizosphere. However, the roles of organic acid components in this process have not been well studied. In this study the colonization of a plant growth-promoting rhizobacterium, Bacillus amyloliquefaciens SQR9, on cucumber root infected by Fusarium oxysporum f. sp. cucumerinum J. H. Owen (FOC) was investigated. Chemotaxis and biofilm formation response of SQR9 to root exudates and their organic acid components were analysed. Infection of FOC on cucumber had a positive effect (3.30-fold increase) on the root colonization of SQR9 compared with controls. Root secretion of citric acid (2.3 ± 0.2 μM) and fumaric acid (5.7 ± 0.5 μM) was enhanced in FOC-infected cucumber plants. Bacillus amyloliquefaciens SQR9 exhibited enhanced chemotaxis to root exudates of FOC-infected cucumber seedlings. Further experiments demonstrated that citric acid acts as a chemoattractant and fumaric acid as a stimulator of biofilm formation in this process. These results suggest that root exudates mediate the interaction of cucumber root and rhizosphere strain B. amyloliquefaciens SQR9 and enhance its root colonization. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

The effect of graphene oxide on adventitious root formation and growth in apple.

PubMed

Li, Feihong; Sun, Chao; Li, Xuehan; Yu, Xinyi; Luo, Chao; Shen, Yanying; Qu, Shenchun

2018-05-30

Graphene, a new type of nanomaterial, has unique physical properties and important potential biological applications. However, few studies have been conducted on the environmental impact of graphene. Therefore, to explore the effect of graphene on plants, three-week-old, tissue-cultured 'Gala' apple plants (Malus domestica) were treated with different concentrations (0, 0.1, 1, 10 mg/L) of graphene oxide (GO) and examined after 40 days. Results indicated that adventitious root length, moisture content and the number of lateral roots were all inhibited by 0.1-10 mg/L GO. At 0.1 and 1 mg/L GO, however, the number of adventitious roots and the rooting rate exhibited a significant increase, relative to the control (no GO). Treatment with GO increased the activities of oxidative stress enzymes including catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in the apple plants, relative to controls. Malondialdehyde (MDA) levels were also significantly decreased at 10 mg/L GO. Treatment of apple plantlets with 0.1 mg/L GO increased the transcript abundance of auxin efflux carrier (PIN7, ABCB1) genes and auxin influx carrier (LAX2, LAX3) genes but inhibited the transcript levels of the ARR3 gene, which involved in cytokinin biosynthesis. Additionally, the transcript levels of ARRO1, ARF19, and TTG1, which play roles in the formation of adventitious roots, lateral roots, and root hairs, respectively, were all decreased in response to treatment with 1 and 10 mg/L GO. Collectively, the results indicate that treatment of 'Gala' apple plants with 0.1 mg/L GO had a positive effect on root formation but a negative effect on root growth. This response may be related to the negative impact of GO on cellular structure and function. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Bilateral presence of two root canals in maxillary central incisors: A rare case study.

PubMed

Kavitha, M; Gokul, Kannan; Ramaprabha, B; Lakshmi, Amudha

2014-04-01

Success in root canal treatment is achieved after thorough cleaning and shaping followed by complete obturation of the canal system. Therefore, endodontic therapy requires specific and complete knowledge of the internal and external dental anatomy, and its variations in presentation. The internal anatomy of the maxillary central incisor is well-known and usually presents one root canal system. This case report describes an endodontic treatment of traumatized both maxillary central incisors with two canal systems. Knowledge of dental anatomy is fundamental for proper endodontic practice. When root canal treatment is performed, the clinician should be aware that both external and internal anatomy may be abnormal.

Coronally advanced flap with and without a xenogenic collagen matrix in the treatment of multiple recessions: a randomized controlled clinical study.

PubMed

Cardaropoli, Daniele; Tamagnone, Lorenzo; Roffredo, Alessandro; Gaveglio, Lorena

2014-01-01

Multiple adjacent recession defects were treated in 32 patients using a coronally advanced flap (CAF) with or without a collagen matrix (CM). The percentage of root coverage was 81.49% ± 23.45% (58% complete root coverage) for CAF sites (control) and 93.25% ± 10.01% root coverage (72% complete root coverage) for CM plus CAF sites (test). The results achieved in the test group were significantly greater than in the control group, indicating that CM plus CAF is a suitable option for the treatment of multiple adjacent gingival recessions.

Storage root of cassava: Morphological types, anatomy, formation, growth, development and harvest time

USDA-ARS?s Scientific Manuscript database

Cassava (Manihot esculenta, Crantz) is considered a starchy root crop that provides staple food for millions of people in tropical and subtropical regions of the world. Research efforts are directed towards genetic breeding and cultivation of cassava to improve cassava storage root starch production...

Substance P increases production of proinflammatory cytokines and formation of osteoclasts in dental pulp fibroblasts in patients with severe orthodontic root resorption.

PubMed

Yamaguchi, Masaru; Ozawa, Yasuhito; Mishima, Hiroyuki; Aihara, Norihito; Kojima, Tadashi; Kasai, Kazutaka

2008-05-01

The objective of this study was to determine the extent to which substance P (SP) increases proinflammatory cytokine production and osteoclast formation of human dental pulp fibroblasts (HDPF) in patients with severe orthodontically induced inflammatory root resorption (OIIRR). HDPF were obtained from 5 patients with severe apical root resorption after orthodontic treatment. The levels of interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha were determined after 24 hours by using ELISA kits. Furthermore, culture supernatants were added to cultured human osteoclasts, and osteoclast formation was observed after tartrate-resistant acid phosphatase (TRAP) staining and the formation of resorption cavities. Stimulation with SP increased the levels of IL-1beta, IL-6, and TNF-alpha, in a time- and concentration-dependent manner, although the increase was greater in the severe root resorption (SRR) group than in the nonresorption (NR) group (P < 0.001, 3-way repeated measures ANOVA). As for osteoclast formation, the numbers of TRAP-positive multinucleate cells and resorptive pits were significantly increased in the SRR group compared with the NR group (P < 0.001, 2-way repeated measures ANOVA). These results suggest that HDPF stimulated with SP might be deeply involved in the progress of inflammation in pulp tissue and the incidence of SRR during orthodontic treatment.

The major-effect quantitative trait locus CsARN6.1 encodes an AAA ATPase domain-containing protein that is associated with waterlogging stress tolerance by promoting adventitious root formation

USDA-ARS?s Scientific Manuscript database

In plants, the formation of hypocotyl-derived adventitious roots (AR) is an important morphological acclimation to waterlogging stress, but its genetic basis is largely unknown. In the present study, with combined use of bulked segregant analysis-based high throughput next-gen whole genome sequencin...

Anti-inflammation effects of Sophora flavescens nanoparticles.

PubMed

Han, Chun-Chao; Wang, Yingzi

2012-08-01

The roots of Sophora flavescens was reported to possess many pharmacological activities including anti-inflammatory, antiashmatic, antithelmintic, free radical scavenging and antimicrobial activities. However, the low saturated solubility and dissolution velocity of S. flavescens lead to poor bioavailability. The S. flavescens nanoparticles (SFNP) were prepared by a combination of ultrasound and hydrolysis developed by the authors. The drug dissolution profiles of SFNP in both pH 6.8 and pH 2 media showed complete dissolution within 30 min. The seropharmacology study showed that oral S. flavescens absorption in the SFNP was significantly increased. Anti-inflammation assay revealed the therapeutic efficiency of S. flavescens significantly enhanced upon nanoparticle formation.

A complete system for 3D reconstruction of roots for phenotypic analysis.

PubMed

Kumar, Pankaj; Cai, Jinhai; Miklavcic, Stanley J

2015-01-01

Here we present a complete system for 3D reconstruction of roots grown in a transparent gel medium or washed and suspended in water. The system is capable of being fully automated as it is self calibrating. The system starts with detection of root tips in root images from an image sequence generated by a turntable motion. Root tips are detected using the statistics of Zernike moments on image patches centred on high curvature points on root boundary and Bayes classification rule. The detected root tips are tracked in the image sequence using a multi-target tracking algorithm. Conics are fitted to the root tip trajectories using a novel ellipse fitting algorithm which weighs the data points by its eccentricity. The conics projected from the circular trajectory have a complex conjugate intersection which are image of the circular points. Circular points constraint the image of the absolute conics which are directly related to the internal parameters of the camera. The pose of the camera is computed from the image of the rotation axis and the horizon. The silhouettes of the roots and camera parameters are used to reconstruction the 3D voxel model of the roots. We show the results of real 3D reconstruction of roots which are detailed and realistic for phenotypic analysis.

Nitrogen affects cluster root formation and expression of putative peptide transporters

PubMed Central

Paungfoo-Lonhienne, Chanyarat; Schenk, Peer M.; Lonhienne, Thierry G. A.; Brackin, Richard; Meier, Stefan; Rentsch, Doris; Schmidt, Susanne

2009-01-01

Non-mycorrhizal Hakea actites (Proteaceae) grows in heathland where organic nitrogen (ON) dominates the soil nitrogen (N) pool. Hakea actites uses ON for growth, but the role of cluster roots in ON acquisition is unknown. The aim of the present study was to ascertain how N form and concentration affect cluster root formation and expression of peptide transporters. Hydroponically grown plants produced most biomass with low molecular weight ON>inorganic N>high molecular weight ON, while cluster roots were formed in the order no-N>ON>inorganic N. Intact dipeptide was transported into roots and metabolized, suggesting a role for the peptide transporter (PTR) for uptake and transport of peptides. HaPTR4, a member of subgroup II of the NRT1/PTR transporter family, which contains most characterized di- and tripeptide transporters in plants, facilitated transport of di- and tripeptides when expressed in yeast. No transport activity was demonstrated for HaPTR5 and HaPTR12, most similar to less well characterized transporters in subgroup III. The results provide further evidence that subgroup II of the NRT1/PTR family contains functional di- and tripeptide transporters. Green fluorescent protein fusion proteins of HaPTR4 and HaPTR12 localized to tonoplast, and plasma- and endomembranes, respectively, while HaPTR5 localized to vesicles of unknown identity. Grown in heathland or hydroponic culture with limiting N supply or starved of nutrients, HaPTR genes had the highest expression in cluster roots and non-cluster roots, and leaf expression increased upon re-supply of ON. It is concluded that formation of cluster roots and expression of PTR are regulated in response to N supply. PMID:19380419

Root growth during molar eruption in extant great apes.

PubMed

Kelley, Jay; Dean, Christopher; Ross, Sasha

2009-01-01

While there is gradually accumulating knowledge about molar crown formation and the timing of molar eruption in extant great apes, very little is known about root formation during the eruption process. We measured mandibular first and second molar root lengths in extant great ape osteological specimens that died while either the first or second molars were in the process of erupting. For most specimens, teeth were removed so that root lengths could be measured directly. When this was not possible, roots were measured radiographically. We were particularly interested in the variation in the lengths of first molar roots near the point of gingival emergence, so specimens were divided into early, middle and late phases of eruption based on the number of cusps that showed protein staining, with one or two cusps stained equated with immediate post-gingival emergence. For first molars at this stage, Gorilla has the longest roots, followed by Pongo and Pan. Variation in first molar mesial root lengths at this stage in Gorilla and Pan, which comprise the largest samples, is relatively low and represents no more than a few months of growth in both taxa. Knowledge of root length at first molar emergence permits an assessment of the contribution of root growth toward differences between great apes and humans in the age at first molar emergence. Root growth makes up a greater percentage of the time between birth and first molar emergence in humans than it does in any of the great apes. Copyright (c) 2009 S. Karger AG, Basel.

Healing of intrabony defects and its relationship to root canal therapy. A histologic and histometric study in dogs.

PubMed

Lima, L A; Anderson, G B; Wang, M M; Nasjleti, C E; Morrison, E C; Kon, S; Caffesse, R G

1997-03-01

The purpose of this study was to evaluate the importance of root canal therapy in the healing process of severe intrabony defects. Four beagle dogs were used and 32 interproximal intrabony defects, up to the apical third, were created. Wire ligatures were placed into these defects for plaque accumulation. Three weeks later, the ligatures were removed and 4 different treatment modalities were employed: group 1) scaling and root planing (SRP); group 2) modified Widman flap (MWF); group 3) modified Widman flap and root canal therapy performed at the same time (RCT/MWF); and group 4) modified Widman flap and root canal therapy performed 3 weeks after the surgical procedure (MWF + RCT). Postoperative oral hygiene was obtained by spraying a 0.12% chlorhexidine solution 3 times a week. The animals were sacrificed 7 weeks after treatment. Blocks were obtained and processed for routine histology. Results were expressed as a percentage of the total defect length (TDL). No differences were observed when SRP was compared to MWF. New bone formation (BF) presented better results for SRP (43.4%) and MWF (53.4%) when compared to RCT/MWF (15.5%). New cementum formation (CF) presented better results for SRP (59.8%) and MWF (64.6%) when compared to RCT/MWF (19.3%) and MWF + RCT (31.5%). Connective tissue repair (CTR) presented better results for SRP (72.4%) and MWF (74.2%) when compared to RCT/MWF (47.5%) and MWF + RCT (44.4%). Results were statistically significant at the level of 0.05. Within the limits of this study, it was concluded that root canal therapy performed simultaneously or 3 weeks after surgery modified the healing of intrabony defects, impairing new bone formation, new cementum formation and new attachment.

Rapid auxin-induced nitric oxide accumulation and subsequent tyrosine nitration of proteins during adventitious root formation in sunflower hypocotyls

PubMed Central

Yadav, Sunita; David, Anisha; Baluška, František; Bhatla, Satish C.

2013-01-01

Using NO specific probe (MNIP-Cu), rapid nitric oxide (NO) accumulation as a response to auxin (IAA) treatment has been observed in the protoplasts from the hypocotyls of sunflower seedlings (Helianthus annuus L.). Incubation of protoplasts in presence of NPA (auxin efflux blocker) and PTIO (NO scavenger) leads to significant reduction in NO accumulation, indicating that NO signals represent an early signaling event during auxin-induced response. A surge in NO production has also been demonstrated in whole hypocotyl explants showing adventitious root (AR) development. Evidence of tyrosine nitration of cytosolic proteins as a consequence of NO accumulation has been provided by western blot analysis and immunolocalization in the sections of AR producing hypocotyl segments. Most abundant anti-nitrotyrosine labeling is evident in proteins ranging from 25–80 kDa. Tyrosine nitration of a particular protein (25 kDa) is completely absent in presence of NPA (which suppresses AR formation). Similar lack of tyrosine nitration of this protein is also evident in other conditions which do not allow AR differentiation. Immunofluorescent localization experiments have revealed that non-inductive treatments (such as PTIO) for AR develpoment from hypocotyl segments coincide with symplastic and apoplastic localization of tyrosine nitrated proteins in the xylem elements, in contrast with negligible (and mainly apoplastic) nitration of proteins in the interfascicular cells and phloem elements. Application of NPA does not affect tyrosine nitration of proteins even in the presence of an external source of NO (SNP). Tyrosine nitrated proteins are abundant around the nuclei in the actively dividing cells of the root primordium. Thus, NO-modulated rapid response to IAA treatment through differential distribution of tyrosine nitrated proteins is evident as an inherent aspect of the AR development. PMID:23299324

Regenerative endodontics: a comprehensive review.

PubMed

Kim, S G; Malek, M; Sigurdsson, A; Lin, L M; Kahler, B

2018-05-19

The European Society of Endodontology and the American Association for Endodontists have released position statements and clinical considerations for regenerative endodontics. There is increasing literature on this field since the initial reports of Iwaya et al. (Dental Traumatology, 17, 2001, 185) and Banchs & Trope (Journal of Endodontics, 30, 2004, 196). Endogenous stem cells from an induced periapical bleeding and scaffolds using blood clot, platelet rich plasma or platelet-rich fibrin have been utilized in regenerative endodontics. This approach has been described as a 'paradigm shift' and considered the first treatment option for immature teeth with pulp necrosis. There are three treatment outcomes of regenerative endodontics; (i) resolution of clinical signs and symptoms; (ii) further root maturation; and (iii) return of neurogenesis. It is known that results are variable for these objectives, and true regeneration of the pulp/dentine complex is not achieved. Repair derived primarily from the periodontal and osseous tissues has been shown histologically. It is hoped that with the concept of tissue engineering, namely stem cells, scaffolds and signalling molecules, that true pulp regeneration is an achievable goal. This review discusses current knowledge as well as future directions for regenerative endodontics. Patient-centred outcomes such as tooth discolouration and possibly more appointments with the potential for adverse effects needs to be discussed with patients and parents. Based on the classification of Cvek (Endodontics and Dental Traumatology, 8, 1992, 45), it is proposed that regenerative endodontics should be considered for teeth with incomplete root formation although teeth with near or complete root formation may be more suited for conventional endodontic therapy or MTA barrier techniques. However, much is still not known about clinical and biological aspects of regenerative endodontics. © 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Benefits of flooding-induced aquatic adventitious roots depend on the duration of submergence: linking plant performance to root functioning.

PubMed

Zhang, Qian; Huber, Heidrun; Beljaars, Simone J M; Birnbaum, Diana; de Best, Sander; de Kroon, Hans; Visser, Eric J W

2017-07-01

Temporal flooding is a common environmental stress for terrestrial plants. Aquatic adventitious roots (aquatic roots) are commonly formed in flooding-tolerant plant species and are generally assumed to be beneficial for plant growth by supporting water and nutrient uptake during partial flooding. However, the actual contribution of these roots to plant performance under flooding has hardly been quantified. As the investment into aquatic root development in terms of carbohydrates may be costly, these costs may - depending on the specific environmental conditions - offset the beneficial effects of aquatic roots. This study tested the hypothesis that the balance between potential costs and benefits depends on the duration of flooding, as the benefits are expected to outweigh the costs in long-term but not in short-term flooding. The contribution of aquatic roots to plant performance was tested in Solanum dulcamara during 1-4 weeks of partial submergence and by experimentally manipulating root production. Nutrient uptake by aquatic roots, transpiration and photosynthesis were measured in plants differing in aquatic root development to assess the specific function of these roots. As predicted, flooded plants benefited from the presence of aquatic roots. The results showed that this was probably due to the contribution of roots to resource uptake. However, these beneficial effects were only present in long-term but not in short-term flooding. This relationship could be explained by the correlation between nutrient uptake and the flooding duration-dependent size of the aquatic root system. The results indicate that aquatic root formation is likely to be selected for in habitats characterized by long-term flooding. This study also revealed only limited costs associated with adventitious root formation, which may explain the maintenance of the ability to produce aquatic roots in habitats characterized by very rare or short flooding events. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Enhanced Conjugation of Auxin by GH3 Enzymes Leads to Poor Adventitious Rooting in Carnation Stem Cuttings.

PubMed

Cano, Antonio; Sánchez-García, Ana Belén; Albacete, Alfonso; González-Bayón, Rebeca; Justamante, María Salud; Ibáñez, Sergio; Acosta, Manuel; Pérez-Pérez, José Manuel

2018-01-01

Commercial carnation ( Dianthus caryophyllus ) cultivars are vegetatively propagated from axillary stem cuttings through adventitious rooting; a process which is affected by complex interactions between nutrient and hormone levels and is strongly genotype-dependent. To deepen our understanding of the regulatory events controlling this process, we performed a comparative study of adventitious root (AR) formation in two carnation cultivars with contrasting rooting performance, "2101-02 MFR" and "2003 R 8", as well as in the reference cultivar "Master". We provided molecular evidence that localized auxin response in the stem cutting base was required for efficient adventitious rooting in this species, which was dynamically established by polar auxin transport from the leaves. In turn, the bad-rooting behavior of the "2003 R 8" cultivar was correlated with enhanced synthesis of indole-3-acetic acid conjugated to aspartic acid by GH3 proteins in the stem cutting base. Treatment of stem cuttings with a competitive inhibitor of GH3 enzyme activity significantly improved rooting of "2003 R 8". Our results allowed us to propose a working model where endogenous auxin homeostasis regulated by GH3 proteins accounts for the cultivar dependency of AR formation in carnation stem cuttings.

The root cause of ability and inability to assemble and install components using written manual with or without diagrams among non-native English speakers: Root cause analysis

NASA Astrophysics Data System (ADS)

Shukri, S. Ahmad; Millar, R.; Gratton, G.; Garner, M.; Noh, H. Mohd

2017-12-01

Documentation errors and human errors are often claimed to be the contributory factors for aircraft maintenance mistakes. This paper highlights the preliminary results of the third phase of a four-phased research on communication media that are utilised in an aircraft maintenance organisation. The second phase has looked into the probability of success and failure in completing a task by 60 subjects while in this third phase, the same subjects have been interviewed immediately after completing the task by using Root Cause Analysis (RCA) method. It is discovered that the root cause of their inability to finish the task while using only written manual is the absence of diagrams. However, haste is identified to be the root cause for the incompletion of the task when both manual and diagram are given to the participants. It is observed that those who are able to complete the task is due to their reference to both manual and diagram, simultaneously.

A preliminary report on histological outcome of pulpotomy with endodontic biomaterials vs calcium hydroxide.

PubMed

Nosrat, Ali; Peimani, Ali; Asgary, Saeed

2013-11-01

The purpose of the study was to evaluate human dental pulp response to pulpotomy with calcium hydroxide (CH), mineral trioxide aggregate (MTA), and calcium enriched mixture (CEM) cement. A total of nine erupted third molars were randomly assigned to each pulpotomy group. The same clinician performed full pulpotomies and coronal restorations. The patients were followed clinically for six months; the teeth were then extracted and prepared for histological assessments. The samples were blindly assessed by an independent observer for pulp vitality, pulp inflammation, and calcified bridge formation. All patients were free of clinical signs/symptoms of pulpal/periradicular diseases during the follow up period. In CH group, one tooth had necrotic radicular pulp; other two teeth in this group had vital uninflamed pulps with complete dentinal bridge formation. In CEM cement and MTA groups all teeth had vital uninflamed radicular pulps. A complete dentinal bridge was formed beneath CEM cement and MTA in all roots. Odontoblast-like cells were present beneath CEM cement and MTA in all samples. This study revealed that CEM cement and MTA were reliable endodontic biomaterials in full pulpotomy treatment. In contrast, the human dental pulp response to CH might be unpredictable.

Comparative analysis of endodontic smear layer removal efficacy of 17% ethylenediaminetetraacetic acid, 7% maleic acid, and 2% chlorhexidine using scanning electron microscope: An in vitro study.

PubMed

Attur, Kailash; Joy, Mathew T; Karim, Riyas; Anil Kumar, V J; Deepika, C; Ahmed, Haseena

2016-08-01

The aim of the present study was to evaluate the efficiency of different endodontic irrigants in the removal of smear layer through scanning electron microscopic image analysis. The present in vitro study was carried out on 45 single-rooted extracted human mandibular premolar teeth with single canal and complete root formation. Teeth were randomly assigned to three groups with 15 teeth in each group. Group I samples were irrigated with 17% ethylenediaminetetraacetic (EDTA) irrigation, Group II with 7% maleic acid irrigation, and Group III with 2% chlorhexidine irrigation. Scanning electron microscope evaluation was done for the assessment of smear layer removal in the coronal, middle, and apical thirds. Comparison of the smear layer removal between the three different groups was done by Kruskal-Wallis test, followed by Mann-Whitney U test for comparing individual groups. A P value less than 0.05 was considered to be statistically significant. Statistically significant difference was seen between the two test groups (17% EDTA vs. 7% maleic acid and 17% EDTA vs. 2% chlorhexidine) in smear layer removal at coronal, middle, and apical thirds of the root canal. The most efficient smear layer removal was seen in Group I with 17% EDTA irrigation compared with other groups (P < 0.05) and the least by 2% chlorhexidine. The present study shows that 17% EDTA efficiently removes the smear layer from root canal walls.

Nitrogen and dry-matter partitioning in soybean plants during onset of and recovery from nitrogen stress

NASA Technical Reports Server (NTRS)

Tolley-Henry, L.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

1986-01-01

The study tested the hypothesis that resupplying nitrogen after a period of nitrogen stress leads to restoration of the balance between root and shoot growth and normal functional activity. Nonnodulated soybean plants were grown hydroponically for 14 days with 1.0 mM NO3- in a complete nutrient solution. One set of plants was continued on the complete nutrient solution for 25 days; a second set was given 0.0 mM NO3- for 25 days; and the third set was given 0.0 mM NO3- for 10 days followed by transfer to the complete solution with 1.0 mM NO3- for 15 days. In continuously nitrogen-stressed plants, emergence and expansion of main-stem and branch leaves were severely inhibited as low nitrogen content limited further growth. This was followed by a shift in partitioning of dry matter from the leaves to the roots, resulting in an initial stimulation of root growth and a decreased shoot:root ratio. Reduced nitrogen also was redistributed from the leaves into the stem and roots. When nitrogen stress was relieved, leaf initiation and expansion were renewed. With the restoration of the balance between root and shoot function, the shoot:root ratio and distribution of reduced nitrogen within the plant organs returned to levels similar to those of nonstressed plants.

Effect of polyvinyl alcohol on in vitro rooting capacity of shoots in pear clones (Pyrus communis L.) of different ploidy

USDA-ARS?s Scientific Manuscript database

Poor adventitious root formation is a major obstacle in micropropagation. In this study, intense efforts have been made for improvement of rooting procedures for triploid, tetraploid, and mixploid clones of the pear cultivar, 'Fertility', obtained by in vitro colchicine treatment. An efficient roo...

Nitric oxide is involved in phosphorus deficiency-induced cluster root development and citrate exudation in white lupin

USDA-ARS?s Scientific Manuscript database

White lupin (Lupinus albus) forms specialized cluster roots characterized by exudation of organic anions under phosphorus (P) deficiency. Here, we evaluated the role of nitric oxide (NO) in P deficiency-induced cluster-root formation and citrate exudation in white lupin. Plants were treated with NO ...

A Kinetic Analysis of the Auxin Transcriptome Reveals Cell Wall Remodeling Proteins That Modulate Lateral Root Development in Arabidopsis[W][OPEN

PubMed Central

Lewis, Daniel R.; Olex, Amy L.; Lundy, Stacey R.; Turkett, William H.; Fetrow, Jacquelyn S.; Muday, Gloria K.

2013-01-01

To identify gene products that participate in auxin-dependent lateral root formation, a high temporal resolution, genome-wide transcript abundance analysis was performed with auxin-treated Arabidopsis thaliana roots. Data analysis identified 1246 transcripts that were consistently regulated by indole-3-acetic acid (IAA), partitioning into 60 clusters with distinct response kinetics. We identified rapidly induced clusters containing auxin-response functional annotations and clusters exhibiting delayed induction linked to cell division temporally correlated with lateral root induction. Several clusters were enriched with genes encoding proteins involved in cell wall modification, opening the possibility for understanding mechanistic details of cell structural changes that result in root formation following auxin treatment. Mutants with insertions in 72 genes annotated with a cell wall remodeling function were examined for alterations in IAA-regulated root growth and development. This reverse-genetic screen yielded eight mutants with root phenotypes. Detailed characterization of seedlings with mutations in CELLULASE3/GLYCOSYLHYDROLASE9B3 and LEUCINE RICH EXTENSIN2, genes not normally linked to auxin response, revealed defects in the early and late stages of lateral root development, respectively. The genes identified here using kinetic insight into expression changes lay the foundation for mechanistic understanding of auxin-mediated cell wall remodeling as an essential feature of lateral root development. PMID:24045021

The formation of 3 alpha- and 3 beta-acetoxytropanes by Datura stramonium transformed root cultures involves two acetyl-CoA-dependent acyltransferases.

PubMed

Robins, R J; Bachmann, P; Robinson, T; Rhodes, M J; Yamada, Y

1991-11-04

Tropine (tropan-3 alpha-ol) is an intermediate in the formation of hyoscyamine. An acyltransferase activity that can acetylate tropine using acetylcoenzyme A as cosubstrate has been found in transformed root cultures of Datura stramonium. A further acyltransferase activity that acetylates pseudotropine (tropan-3 beta-ol) with acetyl-coenzyme A is also present. These two activities can be partially resolved by anion-exchange chromatography, some fractions containing only the pseudotropine-utilizing activity. The basic properties of these two enzymes are reported and their roles in forming the observed alkaloid spectrum of D. stramonium roots discussed.

Correlation of the Radiographic and Morphological Features of the Dental Follicle of Third Molars with Incomplete Root Formation

PubMed Central

de OLIVEIRA, David Moraes; de Souza ANDRADE, Emanuel Sávio; da SILVEIRA, Márcia Maria Fonseca; CAMARGO, Igor Batista

2008-01-01

The objective of this study was to determine the correlation of the radiographic and morphological features of the dental follicle of unerupted third molars with incomplete root formation. A cross-sectional study was carried out with 56 patients (105 teeth) aged 13 to 24 years. Panoramic radiography was used to determine the stage of root formation to locate and measure pericoronal radiolucency. The width of the dental follicle ranged from 0.0 to 4.0 mm, the distal face being the one most frequently involved, and stage 7 of root formation showing the highest incidence. An inactive enamel reduced epithelium and inactive epithelium remnant also showed a high incidence. Dense connective tissue showed a high incidence, chronic inflammation was infrequent and calcification was a common finding. There was a significant association between the progression of the rhizogenesis and the transformation of the enamel reduced epithelium into a stratified squamous epithelium. No significant association was found between rhizogenesis and the other morphological findings or between the latter and the width of the pericoronal space. It was concluded that there was no clinically significant correlation between the radiographic and morphological features. Every asymptomatic unerupted third molar should be followed up and the follicular tissue analyzed. PMID:18311329

Gibberellin–Abscisic Acid Balances during Arbuscular Mycorrhiza Formation in Tomato

PubMed Central

Martín-Rodríguez, José A.; Huertas, Raúl; Ho-Plágaro, Tania; Ocampo, Juan A.; Turečková, Veronika; Tarkowská, Danuše; Ludwig-Müller, Jutta; García-Garrido, José M.

2016-01-01

Plant hormones have become appropriate candidates for driving functional plant mycorrhization programs, including the processes that regulate the formation of arbuscules in arbuscular mycorrhizal (AM) symbiosis. Here, we examine the role played by ABA/GA interactions regulating the formation of AM in tomato. We report differences in ABA and GA metabolism between control and mycorrhizal roots. Active synthesis and catabolism of ABA occur in AM roots. GAs level increases as a consequence of a symbiosis-induced mechanism that requires functional arbuscules which in turn is dependent on a functional ABA pathway. A negative interaction in their metabolism has been demonstrated. ABA attenuates GA-biosynthetic and increases GA-catabolic gene expression leading to a reduction in bioactive GAs. Vice versa, GA activated ABA catabolism mainly in mycorrhizal roots. The negative impact of GA3 on arbuscule abundance in wild-type plants is partially offset by treatment with ABA and the application of a GA biosynthesis inhibitor rescued the arbuscule abundance in the ABA-deficient sitiens mutant. These findings, coupled with the evidence that ABA application leads to reduce bioactive GA1, support the hypothesis that ABA could act modifying bioactive GA level to regulate AM. Taken together, our results suggest that these hormones perform essential functions and antagonize each other by oppositely regulating AM formation in tomato roots. PMID:27602046

Comparative Analysis of Crack Propagation in Roots with Hand and Rotary Instrumentation of the Root Canal -An Ex-vivo Study.

PubMed

Kumari, Manju Raj; Krishnaswamy, Manjunath Mysore

2016-07-01

Success of any endodontic treatment depends on strict adherence to 'endodontic triad'. Preparation of root canal system is recognized as being one of the most important stages in root canal treatment. At times, we inevitably end up damaging root dentin which becomes a Gateway for infections like perforation, zipping, dentinal cracks and minute intricate fractures or even vertical root fractures, thereby resulting in failure of treatment. Several factors may be responsible for the formation of dentinal cracks like high concentration of sodium hypochlorite, compaction methods and various canal shaping methods. To compare and evaluate the effects of root canal preparation techniques and instrumentation length on the development of apical root cracks. Seventy extracted premolars with straight roots were mounted on resin blocks with simulated periodontal ligaments, exposing 1-2 mm of the apex followed by sectioning of 1mm of root tip for better visualization under stereomicroscope. The teeth were divided into seven groups of 10 teeth each - a control group and six experimental groups. Subgroup A & B were instrumented with: Stainless Steel hand files (SS) up to Root Canal Length (RCL) & (RCL -1 mm) respectively; sub group C & D were instrumented using ProTaper Universal (PTU) up to RCL and (RCL -1mm) respectively; subgroup E & F were instrumented using ProTaper Next (PTN) up to RCL & (RCL -1 mm) respectively. Stereomicroscopic images of the instrumentation sequence were compared for each tooth. The data was analyzed statistically using descriptive analysis by 'Phi' and 'Cramers' test to find out statistical significance between the groups. The level of significance was set at p< 0.05 using SPSS software. Stainless steel hand file group showed most cracks followed by ProTaper Universal & ProTaper Next though statistically not significant. Samples instrumented up to 1mm short of working length (RCL-1mm) showed lesser number of cracks. All groups showed cracks formation, the stainless steel group being the highest. Working 1mm short of apex reduces the incidence of crack formation.

Transcription factors network in root endosymbiosis establishment and development.

PubMed

Diédhiou, Issa; Diouf, Diaga

2018-02-15

Root endosymbioses are mutualistic interactions between plants and the soil microorganisms (Fungus, Frankia or Rhizobium) that lead to the formation of nitrogen-fixing root nodules and/or arbuscular mycorrhiza. These interactions enable many species to survive in different marginal lands to overcome the nitrogen-and/or phosphorus deficient environment and can potentially reduce the chemical fertilizers used in agriculture which gives them an economic, social and environmental importance. The formation and the development of these structures require the mediation of specific gene products among which the transcription factors play a key role. Three of these transcription factors, viz., CYCLOPS, NSP1 and NSP2 are well conserved between actinorhizal, legume, non-legume and mycorrhizal symbioses. They interact with DELLA proteins to induce the expression of NIN in nitrogen fixing symbiosis or RAM1 in mycorrhizal symbiosis. Recently, the small non coding RNA including micro RNAs (miRNAs) have emerged as major regulators of root endosymbioses. Among them, miRNA171 targets NSP2, a TF conserved in actinorhizal, legume, non-legume and mycorrhizal symbioses. This review will also focus on the recent advances carried out on the biological function of others transcription factors during the root pre-infection/pre-contact, infection or colonization. Their role in nodule formation and AM development will also be described.

Mycorrhizal Formation and Diversity of Endophytic Fungi in Hair Roots of Vaccinium oldhamii Miq. in Japan

PubMed Central

Baba, Takashi; Hirose, Dai; Sasaki, Nobumitsu; Watanabe, Naoaki; Kobayashi, Nobuo; Kurashige, Yuji; Karimi, Fraidoon; Ban, Takuya

2016-01-01

The root diameters as well as colonization and diversity of the root-associating fungi of Vaccinium oldhamii Miq. were investigated in order to obtain information on their mycorrhizal properties. The distal regions of roots had typical hair roots with diameters of less than 100 μm. Ericoid mycorrhizal fungi (ErMF) and dark septate endophytes (DSE) were frequently observed in the roots. Ascomycetes, particularly helotialean fungi, appeared to be dominant among the endophytic fungi of V. oldhamii roots. Furthermore, Rhizoscyphus ericae (Read) Zhuang & Korf and Oidiodendron maius Barron known as ErMF were detected more frequently than other fungal species. PMID:27297892

Dynamics of Aerenchyma Distribution in the Cortex of Sulfate-deprived Adventitious Roots of Maize

PubMed Central

BOURANIS, DIMITRIS L.; CHORIANOPOULOU, STYLIANI N.; KOLLIAS, CHARALAMBOS; MANIOU, PHILIPPA; PROTONOTARIOS, VASSILIS E.; SIYIANNIS, VASSILIS F.; HAWKESFORD, MALCOLM J.

2006-01-01

• Background and Aims Aerenchyma formation in maize adventitious roots is induced in nutrient solution by the deprivation of sulfate (S) under well-oxygenated conditions. The aim of this research was to examine the extent of aerenchyma formation in the cortex of sulfate-deprived adventitious roots along the root axis, in correlation with the presence of reactive oxygen species (ROS), calcium levels and pH of cortex cells and root lignification. • Methods The morphometry of the second whorl of adventitious (W2) roots, subject to S-deprivation conditions throughout development, was recorded in terms of root length and lateral root length and distribution. W2 roots divided into sectors according to the mean length of lateral roots, and cross-sections of each were examined for aerenchyma. In-situ detection of alterations in ROS presence, calcium levels and pH were performed by means of fluorescence microscopy using H2DCF-DA, fluo-3AM and BCECF, respectively. Lignification was detected using the Wiesner test. • Key Results S-deprivation reduced shoot growth and enhanced root proliferation. Aerenchyma was found in the cortex of 77 % of the root length, particularly in the region of emerging or developing lateral roots. The basal and apical sectors had no aerenchyma and no aerenchyma connection was found with the shoot. S-deprivation resulted in alterations of ROS, calcium levels and pH in aerenchymatous sectors compared with the basal non-aerenchymatous region. Lignified epidermal layers were located at the basal and the proximal sectors. S-deprivation resulted in shorter lateral roots in the upper sectors and in a limited extension of the lignified layers towards the next lateral root carrying sector. • Conclusions Lateral root proliferation is accompanied by spatially localized induced cell death in the cortex of developing young maize adventitious roots during S-deprivation. PMID:16481362

Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography

PubMed Central

Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

2015-01-01

Background Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Material/Methods Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. Results ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (p<0.001). Similarly, there was a statistically significant difference in root canal straightening after preparation between the techniques (p<0.001). Conclusions Neither manual nor rotary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal. PMID:26092929

Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography.

PubMed

Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

2015-06-20

Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (p<0.001). Similarly, there was a statistically significant difference in root canal straightening after preparation between the techniques (p<0.001). Neither manual nor rotary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal.

Methane-rich water induces cucumber adventitious rooting through heme oxygenase1/carbon monoxide and Ca(2+) pathways.

PubMed

Cui, Weiti; Qi, Fang; Zhang, Yihua; Cao, Hong; Zhang, Jing; Wang, Ren; Shen, Wenbiao

2015-03-01

Methane-rich water triggered adventitious rooting by regulating heme oxygenase1/carbon monoxide and calcium pathways in cucumber explants. Heme oxygenase1/carbon monoxide (HO1/CO) and calcium (Ca(2+)) were reported as the downstream signals in auxin-induced cucumber adventitious root (AR) formation. Here, we observed that application of methane-rich water (MRW; 80% saturation) obviously induced AR formation in IAA-depleted cucumber explants. To address the universality, we checked adventitious rooting in soybean and mung bean explants, and found that MRW (50 and 10% saturation, respectively) exhibited the similar inducing results. To further determine if the HO1/CO system participated in MRW-induced adventitious rooting, MRW, HO1 inducer hemin, its activity inhibitor zinc protoporphyrin IX (ZnPP), and its catalytic by-products CO, bilirubin, and Fe(2+) were used to detect their effects on cucumber adventitious rooting in IAA-depleted explants. Subsequent results showed that MRW-induced adventitious rooting was blocked by ZnPP and further reversed by 20% saturation CO aqueous solution. However, the other two by-products of HO1, bilirubin and Fe(2+), failed to induce AR formation. Above responses were consistent with the MRW-induced increases of HO1 transcript and corresponding protein level. Further molecular evidence indicted that expression of marker genes, including auxin signaling-related genes and cell cycle regulatory genes, were modulated by MRW alone but blocked by the cotreatment with ZnPP, the latter of which could be significantly rescued by the addition of CO. By using the Ca(2+)-channel blocker and Ca(2+) chelator, the involvement of Ca(2+) pathway in MRW-induced adventitious rooting was also suggested. Together, our results indicate that MRW might serve as a stimulator of adventitious rooting, which was partially mediated by HO1/CO and Ca(2+) pathways.

S-nitrosoglutathione promotes cell wall remodelling, alters the transcriptional profile and induces root hair formation in the hairless root hair defective 6 (rhd6) mutant of Arabidopsis thaliana.

PubMed

Moro, Camila Fernandes; Gaspar, Marilia; da Silva, Felipe Rodrigues; Pattathil, Sivakumar; Hahn, Michael G; Salgado, Ione; Braga, Marcia Regina

2017-03-01

Nitric oxide (NO) exerts pleiotropic effects on plant development; however, its involvement in cell wall modification during root hair formation (RHF) has not yet been addressed. Here, mutants of Arabidopsis thaliana with altered root hair phenotypes were used to assess the involvement of S-nitrosoglutathione (GSNO), the primary NO source, in cell wall dynamics and gene expression in roots induced to form hairs. GSNO and auxin restored the root hair phenotype of the hairless root hair defective 6 (rhd6) mutant. A positive correlation was observed between increased NO production and RHF induced by auxin in rhd6 and transparent testa glabra (ttg) mutants. Deposition of an epitope within rhamnogalacturonan-I recognized by the CCRC-M2 antibody was delayed in root hair cells (trichoblasts) compared with nonhair cells (atrichoblasts). GSNO, but not auxin, restored the wild-type root glycome and transcriptome profiles in rhd6, modulating the expression of a large number of genes related to cell wall composition and metabolism, as well as those encoding ribosomal proteins, DNA and histone-modifying enzymes and proteins involved in post-translational modification. Our results demonstrate that NO plays a key role in cell wall remodelling in trichoblasts and suggest that it also participates in chromatin modification in root cells of A. thaliana. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Treatment of root fracture with accompanying resorption using cermet cement.

PubMed

Lui, J L

1992-02-01

A method of treating an apical root fracture with accompanying resorption at the junction of the fracture fragments using glass-cermet cement is described. Endodontically, the material had previously been used for repair of lateral resorptive root defects and retrograde root fillings. Complete bone regeneration was observed three years post-operatively following treatment of the root fracture in the conventional manner. The various advantages of glass-cermet cement as a root filling material used in the technique described are discussed.

Comparative evaluation of dentinal crack formation after root canal preparation using ProTaper Next, OneShape, and Hyflex EDM

PubMed Central

Das, Sanjib; Pradhan, Prasanti Kumari; Lata, S.; Sinha, Sachidananda Prasad

2018-01-01

Introduction: The purpose of this study was to compare the incidence of dentinal crack formation after root canal preparation using ProTaper Next, OneShape, and Hyflex electrodischarge machining (HEDM). Materials and Methods: A total of 75 extracted mandibular premolars were selected. The root canals were instrumented using ProTaper Next, OneShape, and HEDM rotary files. All roots were horizontally sectioned at 3, 6, and 9 mm from apex with slow-speed saw under water cooling. The sections were observed under a stereomicroscope at ×25 to determine the absence or presence of crack. Data were analyzed using post hoc test and one-way ANOVA. Results: ProTaper Next and HEDM produced significantly less cracks than OneShape. Conclusion: Within the limitation of this in vitro study, it can be concluded that nickel–titanium instruments may cause cracks on the root surface. ProTaper Next and HEDM tend to produce less number of cracks as compared to OneShape. PMID:29674816

Auxin acts as a local morphogenetic trigger to specify lateral root founder cells

PubMed Central

Dubrovsky, Joseph G.; Sauer, Michael; Napsucialy-Mendivil, Selene; Ivanchenko, Maria G.; Friml, Jiří; Shishkova, Svetlana; Celenza, John; Benková, Eva

2008-01-01

Plants exhibit an exceptional adaptability to different environmental conditions. To a large extent, this adaptability depends on their ability to initiate and form new organs throughout their entire postembryonic life. Plant shoot and root systems unceasingly branch and form axillary shoots or lateral roots, respectively. The first event in the formation of a new organ is specification of founder cells. Several plant hormones, prominent among them auxin, have been implicated in the acquisition of founder cell identity by differentiated cells, but the mechanisms underlying this process are largely elusive. Here, we show that auxin and its local accumulation in root pericycle cells is a necessary and sufficient signal to respecify these cells into lateral root founder cells. Analysis of the alf4–1 mutant suggests that specification of founder cells and the subsequent activation of cell division leading to primordium formation represent two genetically separable events. Time-lapse experiments show that the activation of an auxin response is the earliest detectable event in founder cell specification. Accordingly, local activation of auxin response correlates absolutely with the acquisition of founder cell identity and precedes the actual formation of a lateral root primordium through patterned cell division. Local production and subsequent accumulation of auxin in single pericycle cells induced by Cre-Lox-based activation of auxin synthesis converts them into founder cells. Thus, auxin is the local instructive signal that is sufficient for acquisition of founder cell identity and can be considered a morphogenetic trigger in postembryonic plant organogenesis. PMID:18559858

Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

DOE PAGES

Dash, Madhumita; Yordanov, Yordan S.; Georgieva, Tatyana; ...

2017-02-10

Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) genemore » with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.« less

Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dash, Madhumita; Yordanov, Yordan S.; Georgieva, Tatyana

Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) genemore » with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.« less

The major-effect quantitative trait locus CsARN6.1 encodes an AAA ATPase domain-containing protein that is associated with waterlogging stress tolerance by promoting adventitious root formation.

PubMed

Xu, Xuewen; Ji, Jing; Xu, Qiang; Qi, Xiaohua; Weng, Yiqun; Chen, Xuehao

2018-03-01

In plants, the formation of hypocotyl-derived adventitious roots (ARs) is an important morphological acclimation to waterlogging stress; however, its genetic basis remains fragmentary. Here, through combined use of bulked segregant analysis-based whole-genome sequencing, SNP haplotyping and fine genetic mapping, we identified a candidate gene for a major-effect QTL, ARN6.1, that was responsible for waterlogging tolerance due to increased AR formation in the cucumber line Zaoer-N. Through multiple lines of evidence, we show that CsARN6.1 is the most possible candidate for ARN6.1 which encodes an AAA ATPase. The increased formation of ARs under waterlogging in Zaoer-N could be attributed to a non-synonymous SNP in the coiled-coil domain region of this gene. CsARN6.1 increases the number of ARs via its ATPase activity. Ectopic expression of CsARN6.1 in Arabidopsis resulted in better rooting ability and lateral root development in transgenic plants. Transgenic cucumber expressing the CsARN6.1 Asp allele from Zaoer-N exhibited a significant increase in number of ARs compared with the wild type expressing the allele from Pepino under waterlogging conditions. Taken together, these data support that the AAA ATPase gene CsARN6.1 has an important role in increasing cucumber AR formation and waterlogging tolerance. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

Grapevine species from varied native habitats exhibit differences in embolism formation/repair associated with leaf gas exchange and root pressure.

PubMed

Knipfer, Thorsten; Eustis, Ashley; Brodersen, Craig; Walker, Andrew M; McElrone, Andrew J

2015-08-01

Drought induces xylem embolism formation, but grapevines can refill non-functional vessels to restore transport capacity. It is unknown whether vulnerability to embolism formation and ability to repair differ among grapevine species. We analysed in vivo embolism formation and repair using x-ray computed microtomography in three wild grapevine species from varied native habitats (Vitis riparia, V. arizonica, V. champinii) and related responses to measurements of leaf gas exchange and root pressure. Vulnerability to embolism formation was greatest in V. riparia, intermediate in V. arizonica and lowest in V. champinii. After re-watering, embolism repair was rapid and pronounced in V. riparia and V. arizonica, but limited or negligible in V. champinii even after numerous days. Similarly, root pressure measured after re-watering was positively correlated with drought stress severity for V. riparia and V. arizonica (species exhibiting embolism repair) but not for V. champinii. Drought-induced reductions in transpiration were greatest for V. riparia and least in V. champinii. Recovery of transpiration after re-watering was delayed for all species, but was greatest for V. champinii and most rapid in V. arizonica. These species exhibit varied responses to drought stress that involve maintenance/recovery of xylem transport capacity coordinated with root pressure and gas exchange responses. © 2014 John Wiley & Sons Ltd.

Interaction between sulfur and lead in toxicity, iron plaque formation and lead accumulation in rice plant.

PubMed

Yang, Junxing; Liu, Zhiyan; Wan, Xiaoming; Zheng, Guodi; Yang, Jun; Zhang, Hanzhi; Guo, Lin; Wang, Xuedong; Zhou, Xiaoyong; Guo, Qingjun; Xu, Ruixiang; Zhou, Guangdong; Peters, Marc; Zhu, Guangxu; Wei, Rongfei; Tian, Liyan; Han, Xiaokun

2016-06-01

Human activities have resulted in lead and sulfur accumulation in paddy soils in parts of southern China. A combined soil-sand pot experiment was conducted to investigate the influence of S supply on iron plaque formation and Pb accumulation in rice (Oryza sativa L.) under two Pb levels (0 and 600 mg kg(-1)), combined with four S concentrations (0, 30, 60, and 120 mg kg(-1)). Results showed that S supply significantly decreased Pb accumulation in straw and grains of rice. This result may be attributed to the enhancement of Fe plaque formation, decrease of Pb availability in soil, and increase of reduced glutathione (GSH) in rice leaves. Moderate S supply (30 mg kg(-1)) significantly increased Fe plaque formation on the root surface and in the rhizosphere, whereas excessive S supply (60 and 120 mg kg(-1)) significantly decreased the amounts of iron plaque on the root surface. Sulfur supply significantly enhanced the GSH contents in leaves of rice plants under Pb treatment. With excessive S application, the rice root acted as a more effective barrier to Pb accumulation compared with iron plaque. Excessive S supply may result in a higher monosulfide toxicity and decreased iron plaque formation on the root surface during flooded conditions. However, excessive S supply could effectively decrease Pb availability in soils and reduce Pb accumulation in rice plants. Copyright © 2016 Elsevier Inc. All rights reserved.

Elevated levels of N-lauroylethanolamine, an endogenous constituent of desiccated seeds, disrupt normal root development in Arabidopsis thaliana seedlings

NASA Technical Reports Server (NTRS)

Blancaflor, Elison B.; Hou, Guichuan; Chapman, Kent D.

2003-01-01

N-Acylethanolamines (NAEs) are prevalent in desiccated seeds of various plant species, and their levels decline substantially during seed imbibition and germination. Here, seeds of Arabidopsis thaliana (L.) Heynh. were germinated in, and seedlings maintained on, micromolar concentrations of N-lauroylethanolamine (NAE 12:0). NAE 12:0 inhibited root elongation, increased radial swelling of root tips, and reduced root hair numbers in a highly selective and concentration-dependent manner. These effects were reversible when seedlings were transferred to NAE-free medium. Older seedlings (14 days old) acclimated to exogenous NAE by increased formation of lateral roots, and generally, these lateral roots did not exhibit the severe symptoms observed in primary roots. Cells of NAE-treated primary roots were swollen and irregular in shape, and in many cases showed evidence, at the light- and electron-microscope levels, of improper cell wall formation. Microtubule arrangement was disrupted in severely distorted cells close to the root tip, and endoplasmic reticulum (ER)-localized green fluorescent protein (mGFP5-ER) was more abundant, aggregated and distributed differently in NAE-treated root cells, suggesting disruption of proper cell division, endomembrane organization and vesicle trafficking. These results suggest that NAE 12:0 likely influences normal cell expansion in roots by interfering with intracellular membrane trafficking to and/or from the cell surface. The rapid metabolism of NAEs during seed imbibition/germination may be a mechanism to remove this endogenous class of lipid mediators to allow for synchronized membrane reorganization associated with cell expansion.

Microbiologic endodontic status of young traumatized tooth.

PubMed

Baumotte, Karla; Bombana, Antonio C; Cai, Silvana

2011-12-01

Traumatic dental injuries could expose the dentin and, even the pulp, to the oral environment, making possible their contamination. The presence of microorganisms causes pulpal disease and further a tecidual clutter in the periradicular region. The therapy of periradicular pathosis is the consequence of a correct diagnoses which depends on the knowledge of the nature and complexity of endodontic infections. As there is no information on the microbiology of primary endodontic infection in young teeth, the aim of the current study was to investigate the microbiologic status of root canals from permanent young teeth with primary endodontic infection. Twelve patients with the need for endodontic treatment participated in the study. The selected teeth were uniradicular and had an incomplete root formation. They had untreated necrotic pulp. After the access preparation, nineteen microbiologic samples were obtained from the root canals with sterile paper points. Afterwards, the paper points were pooled in a sterile tube containing 2 ml of prereduced transport fluid. The samples were diluted and spread onto plates with selective medium for Enterococcus spp. and for yeast species and onto plates with non-selective medium. A quantitative analysis was performed. The mean number of cultivable bacterial cells in the root canals was 5.7 × 10(6). In four samples (21.05%) black pigmented species were recovered and the mean number of cells was 6.5 × 10(5). One specimen (5.25%) showed the growth of Enterococcus species and the mean number of cells in this case was of 1.5 × 10(4) . The results showed a root canal microbiota with similar design as seen in completely formed teeth. © 2011 John Wiley & Sons A/S.

Nitric oxide signaling is involved in the response to iron deficiency in the woody plant Malus xiaojinensis.

PubMed

Zhai, Longmei; Xiao, Dashuang; Sun, Chaohua; Wu, Ting; Han, Zhenhai; Zhang, Xinzhong; Xu, Xuefeng; Wang, Yi

2016-12-01

To cope with iron (Fe) deficiency, plants have evolved a wide range of adaptive responses from changes in morphology to altered physiological responses. Recent studies have demonstrated that nitric oxide (NO) is involved in the Fe-deficiency response through hormonal signaling pathways. Here, we report that NO plays a significant role in Malus xiaojinensis, an Fe-efficient woody plant. Fe deficiency triggered significant accumulation of NO in the root system, predominantly in the outer cortical and epidermal cells of the elongation zone. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO) completely arrested Fe deficiency-induced root hair formation, blocked the increase in root ferric-chelate reductase activity and in root H + excretion, further reduced the active iron content in young leaves and roots, and prevented the upregulation of the critical Fe-related genes, FIT, MxFRO2-like, and MxIRT1. These conditions were restored under Fe deficiency by treatment with the NO donor, sodium nitroprusside (SNP). Additionally, chlorophyll content and relative expression levels of the genes chlorophyll a deoxygenase (MxCAO) and polyamine oxidase (MxPAO) were not changed significantly following Fe deficiency for 6 d; however, SNP treatment increased MxHEMA gene expression. Interestingly, the Fv/Fm ratio, the maximum quantum yield of photosystem II (PSII), decreased significantly following cPTIO treatment. We observed more severe chlorosis under Fe deficiency with cPTIO treatment for 9 d. These results strongly suggest that NO mediates a range of responses to Fe deficiency in M. xiaojinensis, from morphological changes to the regulation of physiological processes and gene expression. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

In vitro evaluation of efficacy of different rotary instrument systems for gutta percha removal during root canal retreatment

PubMed Central

Joseph, Mercy; Malhotra, Amit; Rao, Murali; Sharma, Abhimanyu; Talwar, Sangeeta

2016-01-01

Background Complete removal of old filling material during root canal retreatment is fundamental for predictable cleaning and shaping of canal anatomy. Most of the retreatment methods tested in earlier studies have shown inability to achieve complete removal of root canal filling. Therefore the aim of this investigation was to assess the efficacy of three different rotary nickel titanium retreatment systems and Hedstrom files in removing filling material from root canals. Material and Methods Sixty extracted mandibular premolars were decoronated to leave 15 mm root. Specimen were hand instrumented and obturated using gutta percha and AH plus root canal sealer. After storage period of two weeks, roots were retreated with three (Protaper retreatment files, Mtwo retreatment files, NRT GPR) rotary retreatment instrument systems and Hedstroem files. Subsequently, samples were sectioned longitudinally and examined under stereomicroscope. Digital images were recorded and evaluated using Digital Image Analysing Software. The retreatment time was recorded for each tooth using a stopwatch. The area of canal and the residual filling material was recorded in mm2 and the percentage of remaining filling material on canal walls was calculated. Data was analysed using ANOVA test. Results Significantly less amount of residual filling material was present in protaper and Mtwo instrumented teeth (p < 0.05) compared to NRT GPR and Hedstrom files group. Protaper instruments also required lesser time during removal of filling material followed by Mtwo instruments, NRT GPR files and Hedstrom files. Conclusions None of the instruments were able to remove the filling material completely from root canal. Protaper universal retreatment system and Mtwo retreatment files were more efficient and faster compared to NRT GPR fles and Hedstrom files. Key words:Gutta-percha removal, nickel titanium, root canal retreatment, rotary instruments. PMID:27703601

Degradation changes in plant root cell wall structural molecules during extended decomposition of important agricultural crop and forage species

USDA-ARS?s Scientific Manuscript database

Little is known about the changes in the cell wall structural molecules lignin, cellulose and hemicellulose as plant roots decompose, despite their importance in the formation of soil organic matter. The objectives of this study were to quantify changes in root composition during 270 d incubations o...

Stimulation of vesicular-arbuscular mycorrhizal fungi by mycotrophic and nonmycotrophic plant root systems.

PubMed

Schreiner, R P; Koide, R T

1993-08-01

Transformed root cultures of three nonmycotrophic and one mycotrophic plant species stimulated germination and hyphal growth of the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum (Becker & Gerd.) in a gel medium. However, only roots of the mycotrophic species (carrot) supported continued hyphal exploration after 3 to 4 weeks and promoted appressoria formation by G. etunicatum.

Localized gene expression changes during adventitious root formation in black walnut (Juglans nigra L.)

Treesearch

Micah E Stevens; Keith E Woeste; Paula M Pijut

2018-01-01

Cutting propagation plays a large role in the forestry and horticulture industries where superior genotypes need to be clonally multiplied. Integral to this process is the ability of cuttings to form adventitious roots. Recalcitrance to adventitious root development is a serious hurdle for many woody plant propagation systems including black walnut (Juglans...

A Continuous Square Root in Formation Filter-Swoother with Discrete Data Update

NASA Technical Reports Server (NTRS)

Miller, J. K.

1994-01-01

A differential equation for the square root information matrix is derived and adapted to the problems of filtering and smoothing. The resulting continuous square root information filter (SRIF) performs the mapping of state and process noise by numerical integration of the SRIF matrix and admits data via a discrete least square update.

Partially arrested root formation in a permanent maxillary central incisor subsequent to trauma to the primary dentition.

PubMed

Nagatani, S; Mathieu, G P

1994-02-01

When the primary dentition sustains a traumatic insult, the development of the succedaneous teeth can be disturbed leading to a number of malformations. In this case report, the patient presented with a history of prior trauma to his primary maxillary incisors which resulted in partially arrested root formation for a permanent incisor. The considerations in formulating a treatment plan which included orthodontics are discussed.

Hydrogen Peroxide Is a Second Messenger in the Salicylic Acid-Triggered Adventitious Rooting Process in Mung Bean Seedlings

PubMed Central

Yang, Wei; Zhu, Changhua; Ma, Xiaoling; Li, Guijun; Gan, Lijun; Ng, Denny; Xia, Kai

2013-01-01

In plants, salicylic acid (SA) is a signaling molecule that regulates disease resistance responses, such as systemic acquired resistance (SAR) and hypertensive response (HR). SA has been implicated as participating in various biotic and abiotic stresses. This study was conducted to investigate the role of SA in adventitious root formation (ARF) in mung bean (Phaseolus radiatus L) hypocotyl cuttings. We observed that hypocotyl treatment with SA could significantly promote the adventitious root formation, and its effects were dose and time dependent. Explants treated with SA displayed a 130% increase in adventitious root number compared with control seedlings. The role of SA in mung bean hypocotyl ARF as well as its interaction with hydrogen peroxide (H2O2) were also elucidated. Pretreatment of mung bean explants with N, N’-dimethylthiourea (DMTU), a scavenger for H2O2, resulted in a significant reduction of SA-induced ARF. Diphenyleneiodonium (DPI), a specific inhibitor of membrane-linked NADPH oxidase, also inhibited the effect of adventitious rooting triggered by SA treatment. The determination of the endogenous H2O2 level indicated that the seedlings treated with SA could induce H2O2 accumulation compared with the control treatment. Our results revealed a distinctive role of SA in the promotion of adventitious rooting via the process of H2O2 accumulation. This conclusion was further supported by antioxidant enzyme activity assays. Based on these results, we conclude that the accumulation of free H2O2 might be a downstream event in response to SA-triggered adventitious root formation in mung bean seedlings. PMID:24386397

An auxin-induced β-type endo-1,4-β-glucanase in poplar is involved in cell expansion and lateral root formation.

PubMed

Yu, Liangliang; Li, Qiong; Zhu, Yingying; Afzal, Muhammad Saddique; Li, Laigeng

2018-05-01

PtrGH9A7, a poplar β-type endo-1,4-β-glucanase gene induced by auxin, promotes both plant growth and lateral root development by enhancing cell expansion. Endo-1,4-β-glucanase (EGase) family genes function in multiple aspects of plant growth and development. Our previous study found that PtrCel9A6, a poplar EGase gene of the β subfamily, is specifically expressed in xylem tissue and is involved in the cellulose biosynthesis required for secondary cell wall formation (Yu et al. in Mol Plant 6:1904-1917, 2013). To further explore the functions and regulatory mechanism of β-subfamily EGases, we cloned and characterized another poplar β-type EGase gene PtrGH9A7, a close homolog of PtrCel9A6. In contrast to PtrCel9A6, PtrGH9A7 is predominantly expressed in parenchyma tissues of the above-ground part; in roots, PtrGH9A7 expression is specifically restricted to lateral root primordia at all stages from initiation to emergence and is strongly induced by auxin application. Heterologous overexpression of PtrGH9A7 promotes plant growth by enhancing cell expansion, suggesting a conserved role for β-type EGases in 1,4-β-glucan chains remodeling, which is required for cell wall loosening. Moreover, the overexpression of PtrGH9A7 significantly increases lateral root number, which might result from improved lateral root primordium development due to enhanced cell expansion. Taken together, these results demonstrate that this β-type EGase induced by auxin signaling has a novel role in promoting lateral root formation as well as in enhancing plant growth.

Eucalyptus hairy roots, a fast, efficient and versatile tool to explore function and expression of genes involved in wood formation.

PubMed

Plasencia, Anna; Soler, Marçal; Dupas, Annabelle; Ladouce, Nathalie; Silva-Martins, Guilherme; Martinez, Yves; Lapierre, Catherine; Franche, Claudine; Truchet, Isabelle; Grima-Pettenati, Jacqueline

2016-06-01

Eucalyptus are of tremendous economic importance being the most planted hardwoods worldwide for pulp and paper, timber and bioenergy. The recent release of the Eucalyptus grandis genome sequence pointed out many new candidate genes potentially involved in secondary growth, wood formation or lineage-specific biosynthetic pathways. Their functional characterization is, however, hindered by the tedious, time-consuming and inefficient transformation systems available hitherto for eucalypts. To overcome this limitation, we developed a fast, reliable and efficient protocol to obtain and easily detect co-transformed E. grandis hairy roots using fluorescent markers, with an average efficiency of 62%. We set up conditions both to cultivate excised roots in vitro and to harden composite plants and verified that hairy root morphology and vascular system anatomy were similar to wild-type ones. We further demonstrated that co-transformed hairy roots are suitable for medium-throughput functional studies enabling, for instance, protein subcellular localization, gene expression patterns through RT-qPCR and promoter expression, as well as the modulation of endogenous gene expression. Down-regulation of the Eucalyptus cinnamoyl-CoA reductase1 (EgCCR1) gene, encoding a key enzyme in lignin biosynthesis, led to transgenic roots with reduced lignin levels and thinner cell walls. This gene was used as a proof of concept to demonstrate that the function of genes involved in secondary cell wall biosynthesis and wood formation can be elucidated in transgenic hairy roots using histochemical, transcriptomic and biochemical approaches. The method described here is timely because it will accelerate gene mining of the genome for both basic research and industry purposes. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Role of Root Hairs and Lateral Roots in Silicon Uptake by Rice

PubMed Central

Ma, Jian Feng; Goto, Shoko; Tamai, Kazunori; Ichii, Masahiko

2001-01-01

The rice plant (Oryza sativa L. cv Oochikara) is known to be a Si accumulator, but the mechanism responsible for the high uptake of Si by the roots is not well understood. We investigated the role of root hairs and lateral roots in the Si uptake using two mutants of rice, one defective in the formation of root hairs (RH2) and another in that of lateral roots (RM109). Uptake experiments with nutrient solution during both a short term (up to 12 h) and relatively long term (26 d) showed that there was no significant difference in Si uptake between RH2 and the wild type (WT), whereas the Si uptake of RM109 was much less than that of WT. The number of silica bodies formed on the third leaf in RH2 was similar to that in WT, but the number of silica bodies in RM109 was only 40% of that in WT, when grown in soil amended with Si under flooded conditions. There was also no difference in the shoot Si concentration between WT and RH2 when grown in soil under upland conditions. Using a multi-compartment transport box, the Si uptake at the root tip (0–1 cm, without lateral roots and root hairs) was found to be similar in WT, RH2, and RM109. However, the Si uptake in the mature zone (1–4 cm from root tip) was significantly lower in RM109 than in WT, whereas no difference was found in Si uptake between WT and RH2. All these results clearly indicate that lateral roots contribute to the Si uptake in rice plant, whereas root hairs do not. Analysis of F2 populations between RM109 and WT showed that Si uptake was correlated with the presence of lateral roots and that the gene controlling formation of lateral roots and Si uptake is a dominant gene. PMID:11743120

Internal aeration of paddy field rice (Oryza sativa) during complete submergence---importance of light and floodwater O2.

PubMed

Winkel, Anders; Colmer, Timothy D; Ismail, Abdelbagi M; Pedersen, Ole

2013-03-01

Flash floods can submerge paddy field rice (Oryza sativa), with adverse effects on internal aeration, sugar status and survival. Here, we investigated the in situ aeration of roots of rice during complete submergence, and elucidated how underwater photosynthesis and floodwater pO(2) influence root aeration in anoxic soil. In the field, root pO(2) was measured using microelectrodes during 2 d of complete submergence. Leaf gas films that formed on the superhydrophobic leaves were left intact, or experimentally removed, to elucidate their effect on internal aeration. In darkness, root pO(2) declined to very low concentrations (0.24 kPa) and was strongly correlated with floodwater pO(2). In light, root pO(2) was high (14 kPa) and primarily a function of the incident light determining the rates of underwater net photosynthesis. Plants with intact leaf gas films maintained higher underwater net photosynthesis relative to plants without gas films when the submerged shoots were in light. During complete submergence, internal aeration of rice in the field relies on underwater photosynthesis during the day and entry of O(2) from the floodwater during the night. Leaf gas films enhance photosynthesis during submergence leading to improved O(2) production and sugar status, and therefore contribute to the submergence tolerance of rice. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Enhanced Conjugation of Auxin by GH3 Enzymes Leads to Poor Adventitious Rooting in Carnation Stem Cuttings

PubMed Central

Cano, Antonio; Sánchez-García, Ana Belén; Albacete, Alfonso; González-Bayón, Rebeca; Justamante, María Salud; Ibáñez, Sergio; Acosta, Manuel; Pérez-Pérez, José Manuel

2018-01-01

Commercial carnation (Dianthus caryophyllus) cultivars are vegetatively propagated from axillary stem cuttings through adventitious rooting; a process which is affected by complex interactions between nutrient and hormone levels and is strongly genotype-dependent. To deepen our understanding of the regulatory events controlling this process, we performed a comparative study of adventitious root (AR) formation in two carnation cultivars with contrasting rooting performance, “2101–02 MFR” and “2003 R 8”, as well as in the reference cultivar “Master”. We provided molecular evidence that localized auxin response in the stem cutting base was required for efficient adventitious rooting in this species, which was dynamically established by polar auxin transport from the leaves. In turn, the bad-rooting behavior of the “2003 R 8” cultivar was correlated with enhanced synthesis of indole-3-acetic acid conjugated to aspartic acid by GH3 proteins in the stem cutting base. Treatment of stem cuttings with a competitive inhibitor of GH3 enzyme activity significantly improved rooting of “2003 R 8”. Our results allowed us to propose a working model where endogenous auxin homeostasis regulated by GH3 proteins accounts for the cultivar dependency of AR formation in carnation stem cuttings. PMID:29755501

Utilizing collagen membranes for guided tissue regeneration-based root coverage.

PubMed

Wang, Hom-Lay; Modarressi, Marmar; Fu, Jia-Hui

2012-06-01

Gingival recession is a common clinical problem that can result in hypersensitivity, pain, root caries and esthetic concerns. Conventional soft tissue procedures for root coverage require an additional surgical site, thereby causing additional trauma and donor site morbidity. In addition, the grafted tissues heal by repair, with formation of long junctional epithelium with some connective tissue attachment. Guided tissue regeneration-based root coverage was thus developed in an attempt to overcome these limitations while providing comparable clinical results. This paper addresses the biologic foundation of guided tissue regeneration-based root coverage, and describes the indications and contraindications for this technique, as well as the factors that influence outcomes. The step-by-step clinical techniques utilizing collagen membranes are also described. In comparison with conventional soft tissue procedures, the benefits of guided tissue regeneration-based root coverage procedures include new attachment formation, elimination of donor site morbidity, less chair-time, and unlimited availability and uniform thickness of the product. Collagen membranes, in particular, benefit from product biocompatibility with the host, while promoting chemotaxis, hemostasis, and exchange of gas and nutrients. Such characteristics lead to better wound healing by promoting primary wound coverage, angiogenesis, space creation and maintenance, and clot stability. In conclusion, collagen membranes are a reliable alternative for use in root coverage procedures. © 2012 John Wiley & Sons A/S.

AOX1-Subfamily Gene Members in Olea europaea cv. "Galega Vulgar"-Gene Characterization and Expression of Transcripts during IBA-Induced in Vitro Adventitious Rooting.

PubMed

Velada, Isabel; Grzebelus, Dariusz; Lousa, Diana; M Soares, Cláudio; Santos Macedo, Elisete; Peixe, Augusto; Arnholdt-Schmitt, Birgit; G Cardoso, Hélia

2018-02-17

Propagation of some Olea europaea L. cultivars is strongly limited due to recalcitrant behavior in adventitious root formation by semi-hardwood cuttings. One example is the cultivar "Galega vulgar". The formation of adventitious roots is considered a morphological response to stress. Alternative oxidase (AOX) is the terminal oxidase of the alternative pathway of the plant mitochondrial electron transport chain. This enzyme is well known to be induced in response to several biotic and abiotic stress situations. This work aimed to characterize the alternative oxidase 1 (AOX1)-subfamily in olive and to analyze the expression of transcripts during the indole-3-butyric acid (IBA)-induced in vitro adventitious rooting (AR) process. OeAOX1a (acc. no. MF410318) and OeAOX1d (acc. no. MF410319) were identified, as well as different transcript variants for both genes which resulted from alternative polyadenylation events. A correlation between transcript accumulation of both OeAOX1a and OeAOX1d transcripts and the three distinct phases (induction, initiation, and expression) of the AR process in olive was observed. Olive AOX1 genes seem to be associated with the induction and development of adventitious roots in IBA-treated explants. A better understanding of the molecular mechanisms underlying the stimulus needed for the induction of adventitious roots may help to develop more targeted and effective rooting induction protocols in order to improve the rooting ability of difficult-to-root cultivars.

Phosphorus deficiency affects the allocation of below-ground resources to combined cluster roots and nodules in Lupinus albus.

PubMed

Thuynsma, Rochelle; Valentine, Alex; Kleinert, Aleysia

2014-02-15

Lupins can rely on both cluster roots and nodules for P acquisition and biological nitrogen fixation (BNF), respectively. The resource allocation (C, N and P) between cluster roots and nodules has been largely understudied during P-deficient conditions. The aim of this investigation was therefore to determine the changes in resource allocation between these organs during fluctuations in P supply. Lupinus albus was cultivated in sand culture for 3 weeks, with either sufficient (2 mM high) or limiting (0.1 mM low) P supply. Although variation on P supply had no effect on the total biomass, there were significant differences in specialised below-ground organ allocation to cluster roots and nodule formation. Cluster root formation and the associated C-costs increased during low P supply, but at sufficient P-supply the construction and growth respiration costs of cluster roots declined along with their growth. In contrast to the cluster root decline at high P supply, there was an increase in nodule growth allocation and corresponding C-costs. However, this was not associated with an increase in BNF. Since cluster roots were able to increase P acquisition under low P conditions, this below-ground investment may also have benefited the P nutrition of nodules. These findings provide evidence that when lupins acquire N via BNF in their nodules, there may be a trade-off in resource allocation between cluster roots and nodules. Copyright © 2013 Elsevier GmbH. All rights reserved.

[Endodontic treatment of a periapical lesion causing root separation].

PubMed

Canalda Sahli, C

1990-01-01

A case is presented of a periapical lesion of a rather large size, which produced an important separation of two inferior incisor roots. The root canal was treated, with calcium hydroxide overextending the apex. Clinic and radiographic control after two years complete reparation of the periapex.

Promotion of adventitious root formation of difficult-to-root hardwood tree species

Treesearch

Paula M. Pijut; Keith E. Woeste; Charles H. Michler

2011-01-01

North American hardwood tree species, such as alder (Alnus spp.), ash (Fraxinus spp.), basswood (Tilia spp.), beech (Fagus spp.), birch (Betula spp.), black cherry (Prunus seratina), black walnut (Juglans nigra), black willow (...

Pulp Revascularization: A Literature Review

PubMed Central

Araújo, Pollyana Rodrigues de Souza; Silva, Luciano Barreto; Neto, Alexandrino Pereira dos Santos; Almeida de Arruda, José Alcides; Álvares, Pâmella Recco; Sobral, Ana Paula Veras; Júnior, Severino Alves; Leão, Jair Carneiro; Braz da Silva, Rodivan; Sampaio, Gerhilde Callou

2017-01-01

Reestablishing blood flow and allowing the continuation of root development are some of the objectives of pulp revascularization. This procedure is currently indicated for teeth with incomplete root formation as an alternative to the traditional treatment of apecification, which consists of inserting calcium hydroxide paste into the root canal for a determined time period in order to induce the formation of a calcified barrier. Although it is considered as the most classically employed therapy, the permanence of the paste for long time periods may lead to the weakening of the root due to hygroscopic properties, as well as proteolytic activities of calcium hydroxide. Therefore, there has been a permanent search for alternatives which allow the full development of immature teeth. Revascularization has emerged as such an alternative, and a range of treatment protocols can be found in the scientific literature. The aim of this paper is to accomplish a literature review concerning this issue. PMID:28567136

Seed-vectored endophytic bacteria modulate development of rice seedlings.

PubMed

Verma, S K; Kingsley, K; Irizarry, I; Bergen, M; Kharwar, R N; White, J F

2017-06-01

The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development. © 2017 The Society for Applied Microbiology.

Forming Completely Penetrated Welded T-joints when Pulsed Arc Welding

NASA Astrophysics Data System (ADS)

Krampit, N. Yu; Krampit, M. A.; Sapozhkov, A. S.

2016-04-01

The paper is focused on revealing the influence of welding parameters on weld formation when pulsed arc welding. As an experimental sample a T-joint over 10 mm was selected. Welding was carried out in flat position, which required no edge preparation but provided mono-directional guaranteed root penetration. The following parameters of welding were subjected to investigation: gap in the joint, wire feed rate and incline angles of the torch along and across the weld axis. Technological recommendations have been made with respect to pulsed arc welding; the cost price of product manufacturing can be reduced on their basis due to reduction of labor input required by machining, lowering consumption of welding materials and electric power.

Occurrence of mycorrhizae after logging and slash burning in the Douglas-fir forest type.

Treesearch

Ernest Wright; Robert F. Tarrant

1958-01-01

The association of certain fungi with plant roots results in formation of an organ called a mycorrhiza. There are two principal types of mycorrhizae: those with the fungus confined internally in the root, or endotrophic mycorrhizae, and those with both internal fungus development and an external fungal mantle enveloping the root tips, or ectotrophic mycorrhizae....

Stimulation of Vesicular-Arbuscular Mycorrhizal Fungi by Mycotrophic and Nonmycotrophic Plant Root Systems

PubMed Central

Schreiner, R. Paul; Koide, Roger T.

1993-01-01

Transformed root cultures of three nonmycotrophic and one mycotrophic plant species stimulated germination and hyphal growth of the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum (Becker & Gerd.) in a gel medium. However, only roots of the mycotrophic species (carrot) supported continued hyphal exploration after 3 to 4 weeks and promoted appressoria formation by G. etunicatum. Images PMID:16349030

Local Auxin Biosynthesis Mediated by a YUCCA Flavin Monooxygenase Regulates Haustorium Development in the Parasitic Plant Phtheirospermum japonicum.

PubMed

Ishida, Juliane K; Wakatake, Takanori; Yoshida, Satoko; Takebayashi, Yumiko; Kasahara, Hiroyuki; Wafula, Eric; dePamphilis, Claude W; Namba, Shigetou; Shirasu, Ken

2016-08-01

Parasitic plants in the Orobanchaceae cause serious agricultural problems worldwide. Parasitic plants develop a multicellular infectious organ called a haustorium after recognition of host-released signals. To understand the molecular events associated with host signal perception and haustorium development, we identified differentially regulated genes expressed during early haustorium development in the facultative parasite Phtheirospermum japonicum using a de novo assembled transcriptome and a customized microarray. Among the genes that were upregulated during early haustorium development, we identified YUC3, which encodes a functional YUCCA (YUC) flavin monooxygenase involved in auxin biosynthesis. YUC3 was specifically expressed in the epidermal cells around the host contact site at an early time point in haustorium formation. The spatio-temporal expression patterns of YUC3 coincided with those of the auxin response marker DR5, suggesting generation of auxin response maxima at the haustorium apex. Roots transformed with YUC3 knockdown constructs formed haustoria less frequently than nontransgenic roots. Moreover, ectopic expression of YUC3 at the root epidermal cells induced the formation of haustorium-like structures in transgenic P. japonicum roots. Our results suggest that expression of the auxin biosynthesis gene YUC3 at the epidermal cells near the contact site plays a pivotal role in haustorium formation in the root parasitic plant P. japonicum. © 2016 American Society of Plant Biologists. All rights reserved.

Hormonal interactions during cluster-root development in phosphate-deficient white lupin (Lupinus albus L.).

PubMed

Wang, Zhengrui; Rahman, A B M Moshiur; Wang, Guoying; Ludewig, Uwe; Shen, Jianbo; Neumann, Günter

2015-04-01

This study addresses hormonal interactions involved in cluster-root (CR) development of phosphate (Pi)-deficient white lupin (Lupinus albus), which represents the most efficient plant strategy for root-induced mobilisation of sparingly soluble soil phosphorus (P) sources. Shoot-to-root translocation of auxin was unaffected by P-limitation, while strong stimulatory effects of external sucrose on CR formation, even in P-sufficient plants, suggest sucrose, rather than auxins, acts as a shoot-borne signal, triggering the induction of CR primordia. Ethylene may act as mediator of the sucrose signal, as indicated by moderately increased expression of genes involved in ethylene biosynthesis in pre-emergent clusters and by strong inhibitory effects of the ethylene antagonist CoCl2 on CR formation induced by sucrose amendments or P-limitation. As reported in other plants, moderately increased production of brassinosteroids (BRs) and cytokinin, in pre-emergent clusters, may be required for the formation of auxin gradients necessary for induction of CR primordia via interference with auxin biosynthesis and transport. The well-documented inhibition of root elongation by high doses of ethylene may be involved in the growth inhibition of lateral rootlets during CR maturation, indicated by a massive increased expression of gene involved in ethylene production, associated with a declined expression of transcripts with stimulatory effects (BR and auxin-related genes). Copyright © 2014 Elsevier GmbH. All rights reserved.

Adventitious rooting declines with the vegetative to reproductive switch and involves a changed auxin homeostasis.

PubMed

Rasmussen, Amanda; Hosseini, Seyed Abdollah; Hajirezaei, Mohammed-Reza; Druege, Uwe; Geelen, Danny

2015-03-01

Adventitious rooting, whereby roots form from non-root tissues, is critical to the forestry and horticultural industries that depend on propagating plants from cuttings. A major problem is that age of the tissue affects the ability of the cutting to form adventitious roots. Here, a model system has been developed using Pisum sativum to differentiate between different interpretations of ageing. It is shown that the decline in adventitious rooting is linked to the ontogenetic switch from vegetative to floral and is mainly attributed to the cutting base. Using rms mutants it is demonstrated that the decline is not a result of increased strigolactones inhibiting adventitious root formation. Monitoring endogenous levels of a range of other hormones including a range of cytokinins in the rooting zone revealed that a peak in jasmonic acid is delayed in cuttings from floral plants. Additionally, there is an early peak in indole-3-acetic acid levels 6h post excision in cuttings from vegetative plants, which is absent in cuttings from floral plants. These results were confirmed using DR5:GUS expression. Exogenous supplementation of young cuttings with either jasmonic acid or indole-3-acetic acid promoted adventitious rooting, but neither of these hormones was able to promote adventitious rooting in mature cuttings. DR5:GUS expression was observed to increase in juvenile cuttings with increasing auxin treatment but not in the mature cuttings. Therefore, it seems the vegetative to floral ontogenetic switch involves an alteration in the tissue's auxin homeostasis that significantly reduces the indole-3-acetic acid pool and ultimately results in a decline in adventitious root formation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Adventitious rooting declines with the vegetative to reproductive switch and involves a changed auxin homeostasis

PubMed Central

Rasmussen, Amanda; Hosseini, Seyed Abdollah; Hajirezaei, Mohammed-Reza; Druege, Uwe; Geelen, Danny

2015-01-01

Adventitious rooting, whereby roots form from non-root tissues, is critical to the forestry and horticultural industries that depend on propagating plants from cuttings. A major problem is that age of the tissue affects the ability of the cutting to form adventitious roots. Here, a model system has been developed using Pisum sativum to differentiate between different interpretations of ageing. It is shown that the decline in adventitious rooting is linked to the ontogenetic switch from vegetative to floral and is mainly attributed to the cutting base. Using rms mutants it is demonstrated that the decline is not a result of increased strigolactones inhibiting adventitious root formation. Monitoring endogenous levels of a range of other hormones including a range of cytokinins in the rooting zone revealed that a peak in jasmonic acid is delayed in cuttings from floral plants. Additionally, there is an early peak in indole-3-acetic acid levels 6h post excision in cuttings from vegetative plants, which is absent in cuttings from floral plants. These results were confirmed using DR5:GUS expression. Exogenous supplementation of young cuttings with either jasmonic acid or indole-3-acetic acid promoted adventitious rooting, but neither of these hormones was able to promote adventitious rooting in mature cuttings. DR5:GUS expression was observed to increase in juvenile cuttings with increasing auxin treatment but not in the mature cuttings. Therefore, it seems the vegetative to floral ontogenetic switch involves an alteration in the tissue’s auxin homeostasis that significantly reduces the indole-3-acetic acid pool and ultimately results in a decline in adventitious root formation. PMID:25540438

Root iron plaque alleviates cadmium toxicity to rice (Oryza sativa) seedlings.

PubMed

Fu, Youqiang; Yang, Xujian; Shen, Hong

2018-06-18

Iron plaque (IP) on root surface can enhance the tolerance of plants to environmental stresses. However, it remains unclear the impact of Fe 2+ on cadmium (Cd) toxicity to rice (Oryza sativa) seedlings. In this study, the effects of different Fe 2+ and Cd 2+ concentration combinations on rice growth were examined hydroponically. Results indicated that Fe 2+ concentration up to 3.2 mM did not damage rice roots while induced IP formation obviously. Cd 2+ of 10 μM repressed rice growth significantly, while the addition of 0.2 mM Fe 2+ to 10 μM Cd 2+ solution (Cd+Fe) did not damage rice roots, indicating that Fe 2+ could ameliorate Cd toxicity to rice seedlings. Microstructure analysis showed Cd+Fe treatment induced the formation of IP with dense and intricate network structure, Cd adsorption on the root surface was reduced significantly. Cd concentration of rice roots and shoots and Cd translocation from roots to shoots with Fe+Cd treatment were reduced by 34.1%, 36.0% and 20.1%, respectively, in comparison to a single Cd treatment. Noteworthy, the removal of IP resulted in a larger loss of root biomass under Cd treatment. In addition, Cd+Fe treatment increased the activities of root superoxide dismutase and catalase by 105.5% and 177.4%, and decreased H 2 O 2 and O 2 · - accumulation of rice roots by 56.9% and 35.9%, and recovered Cd-triggered electrolyte leakage obviously, when compared with a single Cd treatment. The results from this experiment indicated that the formed dense IP on rice roots decreased Cd absorption and reactive oxygen species accumulation, and Fe 2+ supply alleviated Cd toxicity to rice seedlings. Copyright © 2018 Elsevier Inc. All rights reserved.

Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

NASA Technical Reports Server (NTRS)

Moore, R.; McClelen, C. E.

1989-01-01

Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

Interactions among cluster-root investment, leaf phosphorus concentration, and relative growth rate in two Lupinus species.

PubMed

Wang, Xing; Veneklaas, Erik J; Pearse, Stuart J; Lambers, Hans

2015-09-01

Cluster-root (CR) formation is a desirable trait to improve phosphorus (P) acquisition as global P resources are dwindling. CRs in some lupine species are suppressed at higher P status. Whether increased growth rate enhances CR formation due to a "dilution" of leaf P concentration is unknown. We investigated interactive effects of leaf P status and relative growth rate (RGR) on CR formation in two Lupinus species, which differ in their CR biomass investment. Variation in RGR was imposed by varying day length. Lupinus albus and L. pilosus were grown hydroponically with KH2PO4 at a day length of 6, 10, or 14 h. We used a slightly higher P supply at longer day lengths to avoid a decline in leaf P concentration, which would induce CRs. Cluster-root percentage, leaf P concentrations, and RGR were determined at 22, 38, and 52 d after sowing. Lupinus species grown at similar root P availability, but with a faster growth rate, as dependent on day length, showed a greater CR percentage. Because our aim to achieve exactly the same leaf P concentrations at different day lengths was only partially achieved, we carried out a multiple regression analysis. This analysis showed the CR percentage was strongly and negatively correlated with plant P status and only marginally and positively correlated with RGR. The two Lupinus species invariably formed fewer cluster roots at higher leaf P status, irrespective of RGR. Differences in RGR or leaf P concentration cannot explain the species-specific variation in cluster-root investment. © 2015 Botanical Society of America.

Three-year follow-up results for non-surgical root canal therapy of idiopathic external root resorption on a maxillary canine with MTA: a case report

PubMed Central

Huang, Zheng; Chen, Li-Li; Wang, Cong-Yi; Dai, Lin; Cheng, Bo; Sun, Jun; Sun, Jun

2014-01-01

External root resorption (ERR) is an uncommon and intractable disease. Treatment alternatives are case-dependant and aim for the repair of the resorptive lesion and long-term retention of the tooth. A forty-year-old Asian female was diagnosed with idiopathic ERR on tooth #11 (the left maxillary canine) by CBCT. Non-surgical root canal therapy was completed with the aid of an operating microscope. The apical third of the root canal was filled with warm gutta-percha and the resorption defect was filled with mineral trioxide aggregate (MTA). The periapical radiographs were taken immediately after operation, one-month follow-up, six-month follow-up and three-year follow-up, respectively. Clinically, the canine was asymptomatic, and no evidence of any further resorption was found. The six-month follow-up radiograph showed initial healing of the bony lesion, while the three-year follow-up radiograph manifested almost complete healing. MTA can be a superior material to be successfully used in the non-surgical treatment of ERR. CBCT is very useful for evaluating the true nature and severity of absorption lesions in root resorption. It is the first complete case report from China about non-surgical treatment of severe ERR along with a relatively long term follow-up. PMID:25031758

Inhibition of strigolactones promotes adventitious root formation

PubMed Central

Beveridge, Christine A.; Geelen, Danny

2012-01-01

Roots that form from non-root tissues (adventitious roots) are crucial for cutting propagation in the forestry and horticulture industries. Strigolactone has been demonstrated to be an important regulator of these roots in both Arabidopsis and pea using strigolactone deficient mutants and exogenous hormone applications. Strigolactones are produced from a carotenoid precursor which can be blocked using the widely available but broad terpenoid biosynthesis blocker, fluridone. We demonstrate here that fluridone can be used to promote adventitious rooting in the model species Pisum sativum (pea). In addition, in the garden species Plumbago auriculata and Jasminium polyanthum fluridone was equally as successful at promoting roots as a commercial rooting compound containing NAA and IBA. Our findings demonstrate that inhibition of strigolactone signaling has the potential to be used to improve adventitious rooting in commercially relevant species. PMID:22580687

The DAQ system for the AEḡIS experiment

NASA Astrophysics Data System (ADS)

Prelz, F.; Aghion, S.; Amsler, C.; Ariga, T.; Bonomi, G.; Brusa, R. S.; Caccia, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Ereditato, A.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Hinterberger, A.; Holmestad, H.; Kellerbauer, A.; Krasnický, D.; Lagomarsino, V.; Lansonneur, P.; Lebrun, P.; Malbrunot, C.; Mariazzi, S.; Matveev, V.; Mazzotta, Z.; Müller, S. R.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pacifico, N.; Pagano, D.; Penasa, L.; Petracek, V.; Prevedelli, M.; Ravelli, L.; Rienaecker, B.; Robert, J.; Røhne, O. M.; Rotondi, A.; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Scampoli, P.; Simon, M.; Smestad, L.; Sorrentino, F.; Testera, G.; Tietje, I. C.; Widmann, E.; Yzombard, P.; Zimmer, C.; Zmeskal, J.; Zurlo, N.

2017-10-01

In the sociology of small- to mid-sized (O(100) collaborators) experiments the issue of data collection and storage is sometimes felt as a residual problem for which well-established solutions are known. Still, the DAQ system can be one of the few forces that drive towards the integration of otherwise loosely coupled detector systems. As such it may be hard to complete with off-the-shelf components only. LabVIEW and ROOT are the (only) two software systems that were assumed to be familiar enough to all collaborators of the AEḡIS (AD6) experiment at CERN: working out of the GXML representation of LabVIEW Data types, a semantically equivalent representation as ROOT TTrees was developed for permanent storage and analysis. All data in the experiment is cast into this common format and can be produced and consumed on both systems and transferred over TCP and/or multicast over UDP for immediate sharing over the experiment LAN. We describe the setup that has been able to cater to all run data logging and long term monitoring needs of the AEḡIS experiment so far.

Management of 2 teeth diagnosed with dens invaginatus with regenerative endodontics and apexification in the same patient: a case report and review.

PubMed

Kumar, Harleen; Al-Ali, Muna; Parashos, Peter; Manton, David J

2014-05-01

This review and case report present the treatment of a 10-year-old boy with both permanent maxillary lateral incisors demonstrating Oehlers type II dens invaginatus and pulpal involvement. Treatment was complicated by dental anxiety, supraventricular tachycardia, immature tooth development, and facial cellulitis. An infected necrotic pulp of the permanent maxillary left lateral incisor was treated by apexification and endodontic treatment with mineral trioxide aggregate. The necrotic pulp of the permanent maxillary right lateral incisor was treated with canal debridement and dressing under general anesthesia. Periapical healing of both teeth occurred, with the right lateral incisor showing continued root growth, thickening of the dentinal root walls, and completed apex formation. This tooth responded normally to pulp testing. Twenty-eight months after initial treatment, the right lateral incisor displayed progressive sclerosis of the canal. This case demonstrates possible pulpal regeneration of an infected maxillary right lateral incisor with dens invaginatus and an immature apex after minimal canal debridement. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Arbuscular Mycorrhizal Fungus Enhances Lateral Root Formation in Poncirus trifoliata (L.) as Revealed by RNA-Seq Analysis

PubMed Central

Chen, Weili; Li, Juan; Zhu, Honghui; Xu, Pengyang; Chen, Jiezhong; Yao, Qing

2017-01-01

Arbuscular mycorrhizal fungi (AMF) establish symbiosis with most terrestrial plants, and greatly regulate lateral root (LR) formation. Phosphorus (P), sugar, and plant hormones are proposed being involved in this regulation, however, no global evidence regarding these factors is available so far, especially in woody plants. In this study, we inoculated trifoliate orange seedlings (Poncirus trifoliata L. Raf) with an AMF isolate, Rhizophagus irregularis BGC JX04B. After 4 months of growth, LR formation was characterized, and sugar contents in roots were determined. RNA-Seq analysis was performed to obtain the transcriptomes of LR root tips from non-mycorrhizal and mycorrhizal seedlings. Quantitative real time PCR (qRT-PCR) of selected genes was also conducted for validation. The results showed that AMF significantly increased LR number, as well as plant biomass and shoot P concentration. The contents of glucose and fructose in primary root, and sucrose content in LR were also increased. A total of 909 differentially expressed genes (DEGs) were identified in response to AMF inoculation, and qRT-PCR validated the transcriptomic data. The numbers of DEGs related to P, sugar, and plant hormones were 31, 32, and 25, respectively. For P metabolism, the most up-regulated DEGs mainly encoded phosphate transporter, and the most down-regulated DEGs encoded acid phosphatase. For sugar metabolism, the most up-regulated DEGs encoded polygalacturonase and chitinase. For plant hormones, the most up-regulated DEGs were related to auxin signaling, and the most down-regulated DEGs were related to ethylene signaling. PLS-SEM analysis indicates that P metabolism was the most important pathway by which AMF regulates LR formation in this study. These data reveal the changes of genome-wide gene expression in responses to AMF inoculation in trifoliate orange and provide a solid basis for the future identification and characterization of key genes involved in LR formation induced by AMF. PMID:29238356

Arbuscular Mycorrhizal Fungus Enhances Lateral Root Formation in Poncirus trifoliata (L.) as Revealed by RNA-Seq Analysis.

PubMed

Chen, Weili; Li, Juan; Zhu, Honghui; Xu, Pengyang; Chen, Jiezhong; Yao, Qing

2017-01-01

Arbuscular mycorrhizal fungi (AMF) establish symbiosis with most terrestrial plants, and greatly regulate lateral root (LR) formation. Phosphorus (P), sugar, and plant hormones are proposed being involved in this regulation, however, no global evidence regarding these factors is available so far, especially in woody plants. In this study, we inoculated trifoliate orange seedlings ( Poncirus trifoliata L. Raf) with an AMF isolate, Rhizophagus irregularis BGC JX04B. After 4 months of growth, LR formation was characterized, and sugar contents in roots were determined. RNA-Seq analysis was performed to obtain the transcriptomes of LR root tips from non-mycorrhizal and mycorrhizal seedlings. Quantitative real time PCR (qRT-PCR) of selected genes was also conducted for validation. The results showed that AMF significantly increased LR number, as well as plant biomass and shoot P concentration. The contents of glucose and fructose in primary root, and sucrose content in LR were also increased. A total of 909 differentially expressed genes (DEGs) were identified in response to AMF inoculation, and qRT-PCR validated the transcriptomic data. The numbers of DEGs related to P, sugar, and plant hormones were 31, 32, and 25, respectively. For P metabolism, the most up-regulated DEGs mainly encoded phosphate transporter, and the most down-regulated DEGs encoded acid phosphatase. For sugar metabolism, the most up-regulated DEGs encoded polygalacturonase and chitinase. For plant hormones, the most up-regulated DEGs were related to auxin signaling, and the most down-regulated DEGs were related to ethylene signaling. PLS-SEM analysis indicates that P metabolism was the most important pathway by which AMF regulates LR formation in this study. These data reveal the changes of genome-wide gene expression in responses to AMF inoculation in trifoliate orange and provide a solid basis for the future identification and characterization of key genes involved in LR formation induced by AMF.

Role of HSP101 in the stimulation of nodal root development from the coleoptilar node by light and temperature in maize (Zea mays L.) seedlings.

PubMed

López-Frías, Guillermo; Martínez, Luz María; Ponce, Georgina; Cassab, Gladys I; Nieto-Sotelo, Jorge

2011-08-01

Nodal roots (NRs) constitute the prevalent root system of adult maize plants. NRs emerge from stem nodes located below or above ground, and little is known about their inducing factors. Here, it is shown that precocious development of NRs at the coleoptilar node (NRCNs) occurred in maize seedlings when: (i) dark grown and stimulated by the concurrent action of a single light shock of low intensity white light (2 μmol m(-2) s(-1)) and a single heat shock; (ii) grown under a photoperiod of low intensity light (0.1 μmol m(-2) s(-1)); or (iii) grown in the dark under a thermoperiod (28 °C/34 °C). The light shock effects were synergistic with heat shock and with the photoperiod, whereas the thermoperiodical and photoperiodical effects were additive. Dissection of the primary root or the root cap, to mimic the fatal consequences of severe heat shock, caused negligible effects on NRCN formation, indicating that the shoot is directly involved in perception of the heat shock-inducible signal that triggered NRCN formation. A comparison between hsp101-m5::Mu1/hsp101-m5::Mu1 and Hsp101/Hsp101 seedlings indicated that the heat shock protein 101 (HSP101) chaperone inhibited NRCN formation in the light and in the dark. Stimulation of precocious NRCN formation by light and heat shocks was affected by genetic background and by the stage of seedling development. HSP101 protein levels increased in the coleoptilar node of induced wild-type plants, particularly in the procambial region, where NRCN formation originated. The adaptive relevance of development of NRCNs in response to these environmental cues and hypothetical mechanisms of regulation by HSP101 are discussed. © 2011 The Author(s).

Re-do aortic root replacement after an allograft aortic root replacement.

PubMed

Vrtik, Marian; Tesar, Peter J

2009-10-01

Structural degeneration of allograft aortic root is a global process. In addition to valvular degeneration, the allograft wall calcification poses a risk of systemic calcific embolization and late phase anastomotic aneurysm formation and rupture (anecdotal). Furthermore, the valve annulus is often small, and the tissues are rigid making the implantation of an adequately sized prosthesis within the allograft wall difficult. To avoid these issues, we routinely perform re-do aortic root replacement with either a mechanical valve conduit or bio-root composite graft. The technique has been successfully used in 22 consecutive patients with no operative mortality and minimal morbidity.

Setting the light conditions for measuring root transparency for age-at-death estimation methods.

PubMed

Adserias-Garriga, Joe; Nogué-Navarro, Laia; Zapico, Sara C; Ubelaker, Douglas H

2018-03-01

Age-at-death estimation is one of the main goals in forensic identification, being an essential parameter to determine the biological profile, narrowing the possibility of identification in cases involving missing persons and unidentified bodies. The study of dental tissues has been long considered as a proper tool for age estimation with several age estimation methods based on them. Dental age estimation methods can be divided into three categories: tooth formation and development, post-formation changes, and histological changes. While tooth formation and growth changes are important for fetal and infant consideration, when the end of dental and skeletal growth is achieved, post-formation or biochemical changes can be applied. Lamendin et al. in J Forensic Sci 37:1373-1379, (1992) developed an adult age estimation method based on root transparency and periodontal recession. The regression formula demonstrated its accuracy of use for 40 to 70-year-old individuals. Later on, Prince and Ubelaker in J Forensic Sci 47(1):107-116, (2002) evaluated the effects of ancestry and sex and incorporated root height into the equation, developing four new regression formulas for males and females of African and European ancestry. Even though root transparency is a key element in the method, the conditions for measuring this element have not been established. The aim of the present study is to set the light conditions measured in lumens that offer greater accuracy when applying the Lamendin et al. method modified by Prince and Ubelaker. The results must be also taken into account in the application of other age estimation methodologies using root transparency to estimate age-at-death.

Learning from Adverse Events in Obstetrics: Is a Standardized Computer Tool an Effective Strategy for Root Cause Analysis?

PubMed

Murray-Davis, Beth; McDonald, Helen; Cross-Sudworth, Fiona; Ahmed, Rashid; Simioni, Julia; Dore, Sharon; Marrin, Michael; DeSantis, Judy; Leyland, Nicholas; Gardosi, Jason; Hutton, Eileen; McDonald, Sarah

2015-08-01

Adverse events occur in up to 10% of obstetric cases, and up to one half of these could be prevented. Case reviews and root cause analysis using a structured tool may help health care providers to learn from adverse events and to identify trends and recurring systems issues. We sought to establish the reliability of a root cause analysis computer application called Standardized Clinical Outcome Review (SCOR). We designed a mixed methods study to evaluate the effectiveness of the tool. We conducted qualitative content analysis of five charts reviewed by both the traditional obstetric quality assurance methods and the SCOR tool. We also determined inter-rater reliability by having four health care providers review the same five cases using the SCOR tool. The comparative qualitative review revealed that the traditional quality assurance case review process used inconsistent language and made serious, personalized recommendations for those involved in the case. In contrast, the SCOR review provided a consistent format for recommendations, a list of action points, and highlighted systems issues. The mean percentage agreement between the four reviewers for the five cases was 75%. The different health care providers completed data entry and assessment of the case in a similar way. Missing data from the chart and poor wording of questions were identified as issues affecting percentage agreement. The SCOR tool provides a standardized, objective, obstetric-specific tool for root cause analysis that may improve identification of risk factors and dissemination of action plans to prevent future events.

Evolution and genetics of root hair stripes in the root epidermis.

PubMed

Dolan, L; Costa, S

2001-03-01

Root hair pattern develops in a number of different ways in angiosperm. Cells in the epidermis of some species undergo asymmetric cell divisions to form a smaller daughter cell from which a hair grows, and a larger cell that forms a non-hair epidermal cell. In other species any cell in the epidermis can form a root hair. Hair cells are arranged in files along the Arabidopsis root, located in the gaps between underlying cortical cell files. Epidermal cells overlying a single cortical cell file develop as non-hair epidermal cells. Genetic analysis has identified a transcription factor cascade required for the formation of this pattern. WEREWOLF (WER) and GLABRA2 (GL2) are required for the formation of non-hair epidermal cells while CAPRICE (CPC) is required for hair cell development. Recent analyses of the pattern of epidermal cells among the angiosperms indicate that this striped pattern of cell organization evolved from non-striped ancestors independently in a number of diverse evolutionary lineages. The genetic basis for the evolution of epidermal pattern in angiosperms may now be examined.

The effect of partially exposed connective tissue graft on root-coverage outcomes: a systematic review and meta-analysis.

PubMed

Dodge, Austin; Garcia, Jeffrey; Luepke, Paul; Lai, Yu-Lin; Kassab, Moawia; Lin, Guo-Hao

2018-04-01

The aim of this systematic review was to compare the root-coverage outcomes of using a partially exposed connective tissue graft (CTG) technique with a fully covered CTG technique for root coverage. An electronic search up to February 28 th , 2017, was performed to identify human clinical studies with data comparing outcomes of root coverage using CTG, with and without a partially exposed graft. Five clinical studies were selected for inclusion in this review. For each study, the gain of keratinized gingiva, reduction of recession depth, number of surgical sites achieving complete root coverage, percentage of root coverage, gain of tissue thickness, and changes of probing depth and clinical attachment level were recorded. Meta-analysis for the comparison of complete root coverage between the two techniques presented no statistically significant differences. A statistically significant gain of keratinized tissue in favor of the sites with an exposed CTG and a tendency of greater reduction in recession depth were seen at the sites with a fully covered CTG. Based on the results, the use of a partially exposed CTG in root-coverage procedures could achieve greater gain in keratinized gingiva, while a fully covered CTG might be indicated for procedures aiming to reduce recession depth. © 2018 Eur J Oral Sci.

Root development during soil genesis: effects of root-root interactions, mycorrhizae, and substrate

NASA Astrophysics Data System (ADS)

Salinas, A.; Zaharescu, D. G.

2015-12-01

A major driver of soil formation is the colonization and transformation of rock by plants and associated microbiota. In turn, substrate chemical composition can also influence the capacity for plant colonization and development. In order to better define these relationships, a mesocosm study was set up to analyze the effect mycorrhizal fungi, plant density and rock have on root development, and to determine the effect of root morphology on weathering and soil formation. We hypothesized that plant-plant and plant-fungi interactions have a stronger influence on root architecture and rock weathering than the substrate composition alone. Buffalo grass (Bouteloua dactyloides) was grown in a controlled environment in columns filled with either granular granite, schist, rhyolite or basalt. Each substrate was given two different treatments, including grass-microbes and grass-microbes-mycorrhizae and incubated for 120, 240, and 480 days. Columns were then extracted and analyzed for root morphology, fine fraction, and pore water major element content. Preliminary results showed that plants produced more biomass in rhyolite, followed by schist, basalt, and granite, indicating that substrate composition is an important driver of root development. In support of our hypothesis, mycorrhizae was a strong driver of root development by stimulating length growth, biomass production, and branching. However, average root length and branching also appeared to decrease in response to high plant density, though this trend was only present among roots with mycorrhizal fungi. Interestingly, fine fraction production was negatively correlated with average root thickness and volume. There is also slight evidence indicating that fine fraction production is more related to substrate composition than root morphology, though this data needs to be further analyzed. Our hope is that the results of this study can one day be applied to agricultural research in order to promote the production of crops on traditionally un-arable land.

Phloem Girdling of Norway Spruce Alters Quantity and Quality of Wood Formation in Roots Particularly Under Drought

PubMed Central

Rainer-Lethaus, Gina; Oberhuber, Walter

2018-01-01

Carbon (C) availability plays an essential role in tree growth and wood formation. We evaluated the hypothesis that a decrease in C availability (i) triggers mobilization of C reserves in the coarse roots of Picea abies to maintain growth and (ii) causes modification of wood structure notably under drought. The 6-year-old saplings were subjected to two levels of soil moisture (watered versus drought conditions) and root C status was manipulated by physically blocking phloem transport in the stem at three girdling dates (GDs). Stem girdling was done before the onset of bud break [day of the year (doy) 77], during vigorous aboveground shoot and radial stem growth (GD doy 138), and after cessation of shoot growth (GD doy 190). The effect of blockage of C transport on root growth, root phenology, and wood anatomical traits [cell lumen diameter (CLD) and cell wall thickness (CWT)] in earlywood (EW) and latewood (LW) was determined. To evaluate changes in belowground C status caused by girdling, non-structural carbohydrates (soluble sugars and starch) in coarse roots were determined at the time of girdling and after the growing season. Although fine root mass significantly decreased in response to blockage of phloem C transport, the phenology of root elongation growth was not affected. Surprisingly, radial root growth and CLD of EW tracheids in coarse roots were strikingly increased in drought-stressed trees, when girdling occurred before bud break or during aboveground stem growth. In watered trees, the growth response to girdling was less distinct, but the CWT of EW significantly increased. Starch reserves in the roots of girdled trees significantly decreased in both soil moisture treatments and at all GDs. We conclude that (i) radial growth and wood development in coarse roots of P. abies saplings are not only dependent on current photosynthates, and (ii) blockage of phloem transport induces physiological changes that outweigh drought effects imposed on root cambial activity and cell differentiation. PMID:29636766

Transcriptomic analysis reveals ethylene as stimulator and auxin as regulator of adventitious root formation in petunia cuttings.

PubMed

Druege, Uwe; Franken, Philipp; Lischewski, Sandra; Ahkami, Amir H; Zerche, Siegfried; Hause, Bettina; Hajirezaei, Mohammad R

2014-01-01

Adventitious root (AR) formation in the stem base (SB) of cuttings is the basis for propagation of many plant species and petunia is used as model to study this developmental process. Following AR formation from 2 to 192 hours post-excision (hpe) of cuttings, transcriptome analysis by microarray revealed a change of the character of the rooting zone from SB to root identity. The greatest shift in the number of differentially expressed genes was observed between 24 and 72 hpe, when the categories storage, mineral nutrient acquisition, anti-oxidative and secondary metabolism, and biotic stimuli showed a notable high number of induced genes. Analyses of phytohormone-related genes disclosed multifaceted changes of the auxin transport system, auxin conjugation and the auxin signal perception machinery indicating a reduction in auxin sensitivity and phase-specific responses of particular auxin-regulated genes. Genes involved in ethylene biosynthesis and action showed a more uniform pattern as a high number of respective genes were generally induced during the whole process of AR formation. The important role of ethylene for stimulating AR formation was demonstrated by the application of inhibitors of ethylene biosynthesis and perception as well as of the precursor aminocyclopropane-1-carboxylic acid, all changing the number and length of AR. A model is proposed showing the putative role of polar auxin transport and resulting auxin accumulation in initiation of subsequent changes in auxin homeostasis and signal perception with a particular role of Aux/IAA expression. These changes might in turn guide the entrance into the different phases of AR formation. Ethylene biosynthesis, which is stimulated by wounding and does probably also respond to other stresses and auxin, acts as important stimulator of AR formation probably via the expression of ethylene responsive transcription factor genes, whereas the timing of different phases seems to be controlled by auxin.

Transcriptomic analysis reveals ethylene as stimulator and auxin as regulator of adventitious root formation in petunia cuttings

PubMed Central

Druege, Uwe; Franken, Philipp; Lischewski, Sandra; Ahkami, Amir H.; Zerche, Siegfried; Hause, Bettina; Hajirezaei, Mohammad R.

2014-01-01

Adventitious root (AR) formation in the stem base (SB) of cuttings is the basis for propagation of many plant species and petunia is used as model to study this developmental process. Following AR formation from 2 to 192 hours post-excision (hpe) of cuttings, transcriptome analysis by microarray revealed a change of the character of the rooting zone from SB to root identity. The greatest shift in the number of differentially expressed genes was observed between 24 and 72 hpe, when the categories storage, mineral nutrient acquisition, anti-oxidative and secondary metabolism, and biotic stimuli showed a notable high number of induced genes. Analyses of phytohormone-related genes disclosed multifaceted changes of the auxin transport system, auxin conjugation and the auxin signal perception machinery indicating a reduction in auxin sensitivity and phase-specific responses of particular auxin-regulated genes. Genes involved in ethylene biosynthesis and action showed a more uniform pattern as a high number of respective genes were generally induced during the whole process of AR formation. The important role of ethylene for stimulating AR formation was demonstrated by the application of inhibitors of ethylene biosynthesis and perception as well as of the precursor aminocyclopropane-1-carboxylic acid, all changing the number and length of AR. A model is proposed showing the putative role of polar auxin transport and resulting auxin accumulation in initiation of subsequent changes in auxin homeostasis and signal perception with a particular role of Aux/IAA expression. These changes might in turn guide the entrance into the different phases of AR formation. Ethylene biosynthesis, which is stimulated by wounding and does probably also respond to other stresses and auxin, acts as important stimulator of AR formation probably via the expression of ethylene responsive transcription factor genes, whereas the timing of different phases seems to be controlled by auxin. PMID:25400641

Endodontic management of a mandibular first molar with six root canal systems.

PubMed

Jain, Dilip; Reddy, Smitha; Venigalla, Bhuvan Shome; Kamishetty, Shekhar

2015-01-01

Internal anatomy of pulp is complex. The first mandibular molars typically have two roots, one mesial with two root canals and another distal root, which contains one or two canals. A 20-year-old female patient reported with intermittent pain and incomplete root canal treatment in left lower back region since 1-week. Refined access cavity revealed initially two canals in mesial and two canals in the distal root. With operating microscope and cone beam computerized tomography, two additional canals (L-mesio-buccal and B-mesio-lingual) were identified in mesial root. One-year follow-up showed patient was asymptomatic and complete healing of periapical radiolucency.

Genetic evidence for the vital function of Osterix in cementogenesis.

PubMed

Cao, Zhengguo; Zhang, Hua; Zhou, Xin; Han, Xianglong; Ren, Yinshi; Gao, Tian; Xiao, Yin; de Crombrugghe, Benoit; Somerman, Martha J; Feng, Jian Q

2012-05-01

To date, attempts to regenerate a complete tooth, including the critical periodontal tissues associated with the tooth root, have not been successful. Controversy still exists regarding the origin of the cell source for cellular cementum (epithelial or mesenchymal). This disagreement may be partially due to a lack of understanding of the events leading to the initiation and development of the tooth roots and supportive tissues, such as the cementum. Osterix (OSX) is a transcriptional factor essential for osteogenesis, but its role in cementogenesis has not been addressed. In the present study, we first documented a close relationship between the temporal- and spatial-expression pattern of Osx and the formation of cellular cementum. We then generated 3.6-kilobase (kb) collagen type I (3.6-kb Col 1)-Osx transgenic mice, which displayed accelerated cementum formation versus wild-type (WT) controls. Importantly, the conditional deletion of Osx in the mesenchymal cells with two different Cre systems (the 2.3-kb Col 1 and an inducible CAG-Cre estrogen receptor [CreER]) led to a sharp reduction in cellular cementum formation (including the cementum mass and mineral deposition rate) and gene expression of dentin matrix protein 1 (DMP1) by cementocytes. However, the deletion of the Osx gene after cellular cementum formed did not alter the properties of the mature cementum as evaluated by backscattered scanning electron microscopy (SEM) and resin-casted SEM. Transient transfection of Osx in the cementoblasts in vitro significantly inhibited cell proliferation and increased cell differentiation and mineralization. Taken together, these data support: (1) the mesenchymal origin of cellular cementum (from periodontal ligament [PDL] progenitor cells); (2) the vital role of OSX in controlling the formation of cellular cementum; and (3) the limited remodeling of cellular cementum in adult mice. Copyright © 2012 American Society for Bone and Mineral Research.

Three-year outcomes of root canal treatment: Mining an insurance database.

PubMed

Raedel, Michael; Hartmann, Andrea; Bohm, Steffen; Walter, Michael H

2015-04-01

There is doubt whether success rates of root canal treatments reported from clinical trials are achievable outside of standardized study populations. The aim of this study was to analyse the outcome of a large number of root canal treatments conducted in general practice. The data was collected from the digital database of a major German national health insurance company. All teeth with complete treatment data were included. Only patients who had been insurance members for the whole 3-year period from 2010 to 2012 were eligible. Kaplan-Meier survival analyses were conducted based on completed root canal treatments. Target events were re-interventions as (1) retreatment of the root canal treatment, (2) apical root resection (apicoectomy) and (3) extraction. The influences of vitality status and root numbers on survival were tested with the log-rank test. A total of 556,067 root canal treatments were included. The cumulative overall survival rate for all target events combined was 84.3% for 3 years. The survival rate for nonvital teeth (82.6%) was significantly lower than for vital teeth (85.6%; p<0.001). The survival rate for single rooted teeth (83.4%) was significantly lower than for multi-rooted teeth (85.5%; p<0.001). The most frequent target event was extraction followed by apical root resection and retreatment. Based on these 3-year outcomes, root canal treatment is considered a reliable treatment in practice routine under the conditions of the German national health insurance system. Root canal treatment can be considered as a reliable treatment option suitable to salvage most of the affected teeth. This statement applies to treatments that in the vast majority of cases were delivered by general practitioners under the terms and conditions of a nationwide health insurance system. Copyright © 2015 Elsevier Ltd. All rights reserved.

CONTRIBUTIONS OF CURRENT YEAR PHOTOSYNTHATE TO FINE ROOTS ESTIMATED USING A 13C-DEPLETED CO2 SOURCE

EPA Science Inventory

The quantification of root turnover is necessary for a complete understanding of plant carbon (C) budgets, especially in terms of impacts of global climate change. To improve estimates of root turnover, we present a method to distinguish current- from prior-year allocation of ca...

AOX1-Subfamily Gene Members in Olea europaea cv. “Galega Vulgar”—Gene Characterization and Expression of Transcripts during IBA-Induced in Vitro Adventitious Rooting

PubMed Central

Lousa, Diana; M. Soares, Cláudio; Santos Macedo, Elisete; Arnholdt-Schmitt, Birgit

2018-01-01

Propagation of some Olea europaea L. cultivars is strongly limited due to recalcitrant behavior in adventitious root formation by semi-hardwood cuttings. One example is the cultivar ”Galega vulgar”. The formation of adventitious roots is considered a morphological response to stress. Alternative oxidase (AOX) is the terminal oxidase of the alternative pathway of the plant mitochondrial electron transport chain. This enzyme is well known to be induced in response to several biotic and abiotic stress situations. This work aimed to characterize the alternative oxidase 1 (AOX1)-subfamily in olive and to analyze the expression of transcripts during the indole-3-butyric acid (IBA)-induced in vitro adventitious rooting (AR) process. OeAOX1a (acc. no. MF410318) and OeAOX1d (acc. no. MF410319) were identified, as well as different transcript variants for both genes which resulted from alternative polyadenylation events. A correlation between transcript accumulation of both OeAOX1a and OeAOX1d transcripts and the three distinct phases (induction, initiation, and expression) of the AR process in olive was observed. Olive AOX1 genes seem to be associated with the induction and development of adventitious roots in IBA-treated explants. A better understanding of the molecular mechanisms underlying the stimulus needed for the induction of adventitious roots may help to develop more targeted and effective rooting induction protocols in order to improve the rooting ability of difficult-to-root cultivars. PMID:29462998

Effect of the association between citric acid and EDTA on root surface etching.

PubMed

Manzolli Leite, Fabio Renato; Nascimento, Gustavo Giacomelli; Manzolli Leite, Elza Regina; Leite, Amauri Antiquera; Cezar Sampaio, Josá Eduardo

2013-09-01

This study aims to compare the clot stabilization on root surfaces conditioned with citric acid and ethylenediamine-tetraacetic acid (EDTA). Scaled root samples (n = 100) were set in fve groups: group I-control group (saline solution); group II (24% EDTA); group III (25% citric acid); group IV (EDTA + citric acid); group V (citric acid + EDTA). Fifty samples were assessed using the root surface modifcation index (RSMI). The other 50 received a blood drop after conditioning. Clot formation was assessed using blood elements adhesion index (BEAI). A blind examiner evaluated photomicrographs. Statistical analysis considered p < 0.05. Groups-III and G-V attained the best results for RSMI and BEAI in comparison to control. The worst results for clot stabilization were seen in group-II. EDTA employment before citric acid (group-IV) reduced clot formation in comparison to citric acid use alone (group-III). Root conditioning with citric acid alone and before EDTA had the best results for smear layer removal and clot stabilization. EDTA inhibited clot stabilization on root surface and must have a residual activity once it has diminished clot adhesion to root even after citric acid conditioning. Thus, EDTA can be used to neutralize citric acid effects on periodontal cells without affecting clot stabilization. Clinical signifcance: To demonstrate that citric acid use on root surfaces previously affected by periodontal disease may favor clot stabilization and may have a benefcial effect on surgical outcomes. Also, EDTA can be used to neutralize citric acid effects on periodontal cells.

A Comparative SEM Investigation of Smear Layer Remaining on Dentinal Walls by Three Rotary NiTi Files with Different Cross Sectional Designs in Moderately Curved Canals

PubMed Central

Kakkar, Pooja; Vats, Asit

2015-01-01

Objective: The objective of this study was to compare the smear layer formed on root canal walls during canal preparation of extracted human teeth by Twisted, Mtwo, and ProTaper rotary nickel titanium instruments. Materials and Methods: Sixty single rooted human premolar teeth with root curvature <250 were selected and randomly divided into three Groups (n= 20 teeth per Group). Three types of rotary nickel titanium instruments were used, Twisted (SybronEndo, Orange, CA, USA), Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) according to manufacturer’s instructions to instrument the root canals. Irrigation for all groups was performed after each instrument change with 3ml of 3% sodium hypochlorite followed by Glyde (File Prep, Dentsply, Maillefer, Ballaigues, Switzerland) as chelator paste and lubricant. Three different areas (coronal, middle and apical thirds) of the root canal were evaluated using scanning electron microscopy (SEM). The canal wall of each sample was assessed and compared using a predefined scale for the presence or absence of smear layer. Data were analysed statistically using ANOVA and Tukey HSD test Results: All three groups showed statistically significant more smear layer in the apical thirds of the canal as compared to the coronal and middle thirds (p<0.001). Mtwo rotary file system produced significantly less smear layer (p<0.001) compared to Twisted and ProTaper rotary instruments in the apical portion. Twisted Files resulted in less smear layer formation in the apical thirds of the canal compared to ProTaper rotary instruments but were statistically insignificant. Conclusion: Completely clean root canals were not found after instrumentation with any of the three instruments. Under the confines of this study Mtwo instruments produced significantly cleaner dentin wall surfaces throughout the canal length in comparison to Twisted and ProTaper rotary files. Twisted Files proved to be comparable to ProTaper rotary instruments with respect to canal cleanliness in the apical thirds of the root canal. PMID:25954704

AFLP-based transcript profiling for cassava genome-wide expression analysis in the onset of storage root formation.

PubMed

Sojikul, Punchapat; Kongsawadworakul, Panida; Viboonjun, Unchera; Thaiprasit, Jittrawan; Intawong, Burapat; Narangajavana, Jarunya; Svasti, Mom Rajawong Jisnuson

2010-10-01

Cassava (Manihot esculenta Crantz) is a root crop that accumulates large quantities of starch, and it is an important source of carbohydrate. Study on gene expressions during storage root development provides important information on storage root formation and starch accumulation as well as unlock new traits for improving of starch yield. cDNA-Amplified Fragment Length Polymorphism (AFLP) was used to compare gene expression profiles in fibrous and storage roots of cassava cultivar Kasetsart 50. Total of 155 differentially expressed transcript-derived fragments with undetectable or low expression in leaves were characterized and classified into 11 groups regarding to their functions. The four major groups were no similarity (20%), hypothetical or unknown proteins (17%), cellular metabolism and biosynthesis (17%) and cellular communication and signaling (14%). Interestingly, sulfite reductase (MeKD82), calcium-dependent protein kinase (CDPK) (MeKD83), ent-kaurene synthase (KS) (MeKD106) and hexose transporter (HT) (MeKD154) showed root-specific expression patterns. This finding is consistent with previously reported genes involved in the initiation of potato tuber. Semi-quantitative reverse transcription polymerase chain reaction of early-developed root samples confirmed that those four genes exhibited significant expression with similar pattern in the storage root initiation and early developmental stages. We proposed that KS and HT may involve in transient induction of CDPK expression, which may play an important role in the signaling pathway of storage root initiation. Sulfite reductase, on the other hand, may involve in storage root development by facilitating sulfur-containing protein biosynthesis or detoxifying the cyanogenic glucoside content through aspartate biosynthesis. Copyright © Physiologia Plantarum 2010.

Gravity-dependent differentiation and root coils in Arabidopsis thaliana wild type and phospholipase-A-I knockdown mutant grown on the International Space Station.

PubMed

Scherer, G F E; Pietrzyk, P

2014-01-01

Arabidopsis roots on 45° tilted agar in 1-g grow in wave-like figures. In addition to waves, formation of root coils is observed in several mutants compromised in gravitropism and/or auxin transport. The knockdown mutant ppla-I-1 of patatin-related phospholipase-A-I is delayed in root gravitropism and forms increased numbers of root coils. Three known factors contribute to waving: circumnutation, gravisensing and negative thigmotropism. In microgravity, deprivation of wild type (WT) and mutant roots of gravisensing and thigmotropism and circumnutation (known to slow down in microgravity, and could potentially lead to fewer waves or increased coiling in both WT and mutant). To resolve this, mutant ppla-I-1 and WT were grown in the BIOLAB facility in the International Space Station. In 1-g, roots of both types only showed waving. In the first experiment in microgravity, the mutant after 9 days formed far more coils than in 1-g but the WT also formed several coils. After 24 days in microgravity, in both types the coils were numerous with slightly more in the mutant. In the second experiment, after 9 days in microgravity only the mutant formed coils and the WT grew arcuated roots. Cell file rotation (CFR) on the mutant root surface in microgravity decreased in comparison to WT, and thus was not important for coiling. Several additional developmental responses (hypocotyl elongation, lateral root formation, cotyledon expansion) were found to be gravity-influenced. We tentatively discuss these in the context of disturbances in auxin transport, which are known to decrease through lack of gravity. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

SIZ1 Regulation of Phosphate Starvation-Induced Root Architecture Remodeling Involves the Control of Auxin Accumulation1[C][W][OA

PubMed Central

Miura, Kenji; Lee, Jiyoung; Gong, Qingqiu; Ma, Shisong; Jin, Jing Bo; Yoo, Chan Yul; Miura, Tomoko; Sato, Aiko; Bohnert, Hans J.; Hasegawa, Paul M.

2011-01-01

Phosphate (Pi) limitation causes plants to modulate the architecture of their root systems to facilitate the acquisition of Pi. Previously, we reported that the Arabidopsis (Arabidopsis thaliana) SUMO E3 ligase SIZ1 regulates root architecture remodeling in response to Pi limitation; namely, the siz1 mutations cause the inhibition of primary root (PR) elongation and the promotion of lateral root (LR) formation. Here, we present evidence that SIZ1 is involved in the negative regulation of auxin patterning to modulate root system architecture in response to Pi starvation. The siz1 mutations caused greater PR growth inhibition and LR development of seedlings in response to Pi limitation. Similar root phenotypes occurred if Pi-deficient wild-type seedlings were supplemented with auxin. N-1-Naphthylphthalamic acid, an inhibitor of auxin efflux activity, reduced the Pi starvation-induced LR root formation of siz1 seedlings to a level equivalent to that seen in the wild type. Monitoring of the auxin-responsive reporter DR5::uidA indicated that auxin accumulates in PR tips at early stages of the Pi starvation response. Subsequently, DR5::uidA expression was observed in the LR primordia, which was associated with LR elongation. The time-sequential patterning of DR5::uidA expression occurred earlier in the roots of siz1 as compared with the wild type. In addition, microarray analysis revealed that several other auxin-responsive genes, including genes involved in cell wall loosening and biosynthesis, were up-regulated in siz1 relative to wild-type seedlings in response to Pi starvation. Together, these results suggest that SIZ1 negatively regulates Pi starvation-induced root architecture remodeling through the control of auxin patterning. PMID:21156857

The low-molecular-weight fraction of exopolysaccharide II from Sinorhizobium meliloti is a crucial determinant of biofilm formation.

PubMed

Rinaudi, Luciana V; González, Juan E

2009-12-01

Sinorhizobium meliloti is a soil bacterium that elicits the formation of root organs called nodules on its host plant, Medicago sativa. Inside these structures, the bacteria are able to convert atmospheric nitrogen into ammonia, which is then used by the plant as a nitrogen source. The synthesis by S. meliloti of at least one exopolysaccharide, succinoglycan or EPS II, is essential for a successful symbiosis. While exopolysaccharide-deficient mutants induce the formation of nodules, they fail to invade them, and as a result, no nitrogen fixation occurs. Interestingly, the low-molecular-weight fractions of these exopolysaccharides are the symbiotically active forms, and it has been suggested that they act as signals to the host plant to initiate infection thread formation. In this work, we explored the role of these rhizobial exopolysaccharides in biofilm formation and their importance in the symbiotic relationship with the host. We showed that the ExpR/Sin quorum-sensing system controls biofilm formation in S. meliloti through the production of EPS II, which provides the matrix for the development of structured and highly organized biofilms. Moreover, the presence of the low-molecular-weight fraction of EPS II is vital for biofilm formation, both in vitro and in vivo. This is the first report where the symbiotically active fraction of EPS II is shown to be a critical factor for biofilm formation and root colonization. Thus, the ability of S. meliloti to properly attach to root surfaces and form biofilms conferred by the synthesis of exopolysaccharides may embody the main function of these symbiotically essential molecules.

Comprehensive transcriptome analysis unravels the existence of crucial genes regulating primary metabolism during adventitious root formation in Petunia hybrida.

PubMed

Ahkami, Amirhossein; Scholz, Uwe; Steuernagel, Burkhard; Strickert, Marc; Haensch, Klaus-Thomas; Druege, Uwe; Reinhardt, Didier; Nouri, Eva; von Wirén, Nicolaus; Franken, Philipp; Hajirezaei, Mohammad-Reza

2014-01-01

To identify specific genes determining the initiation and formation of adventitious roots (AR), a microarray-based transcriptome analysis in the stem base of the cuttings of Petunia hybrida (line W115) was conducted. A microarray carrying 24,816 unique, non-redundant annotated sequences was hybridized to probes derived from different stages of AR formation. After exclusion of wound-responsive and root-regulated genes, 1,354 of them were identified which were significantly and specifically induced during various phases of AR formation. Based on a recent physiological model distinguishing three metabolic phases in AR formation, the present paper focuses on the response of genes related to particular metabolic pathways. Key genes involved in primary carbohydrate metabolism such as those mediating apoplastic sucrose unloading were induced at the early sink establishment phase of AR formation. Transcriptome changes also pointed to a possible role of trehalose metabolism and SnRK1 (sucrose non-fermenting 1- related protein kinase) in sugar sensing during this early step of AR formation. Symplastic sucrose unloading and nucleotide biosynthesis were the major processes induced during the later recovery and maintenance phases. Moreover, transcripts involved in peroxisomal beta-oxidation were up-regulated during different phases of AR formation. In addition to metabolic pathways, the analysis revealed the activation of cell division at the two later phases and in particular the induction of G1-specific genes in the maintenance phase. Furthermore, results point towards a specific demand for certain mineral nutrients starting in the recovery phase.

Comprehensive Transcriptome Analysis Unravels the Existence of Crucial Genes Regulating Primary Metabolism during Adventitious Root Formation in Petunia hybrida

PubMed Central

Ahkami, Amirhossein; Scholz, Uwe; Steuernagel, Burkhard; Strickert, Marc; Haensch, Klaus-Thomas; Druege, Uwe; Reinhardt, Didier; Nouri, Eva; von Wirén, Nicolaus; Franken, Philipp; Hajirezaei, Mohammad-Reza

2014-01-01

To identify specific genes determining the initiation and formation of adventitious roots (AR), a microarray-based transcriptome analysis in the stem base of the cuttings of Petunia hybrida (line W115) was conducted. A microarray carrying 24,816 unique, non-redundant annotated sequences was hybridized to probes derived from different stages of AR formation. After exclusion of wound-responsive and root-regulated genes, 1,354 of them were identified which were significantly and specifically induced during various phases of AR formation. Based on a recent physiological model distinguishing three metabolic phases in AR formation, the present paper focuses on the response of genes related to particular metabolic pathways. Key genes involved in primary carbohydrate metabolism such as those mediating apoplastic sucrose unloading were induced at the early sink establishment phase of AR formation. Transcriptome changes also pointed to a possible role of trehalose metabolism and SnRK1 (sucrose non-fermenting 1- related protein kinase) in sugar sensing during this early step of AR formation. Symplastic sucrose unloading and nucleotide biosynthesis were the major processes induced during the later recovery and maintenance phases. Moreover, transcripts involved in peroxisomal beta-oxidation were up-regulated during different phases of AR formation. In addition to metabolic pathways, the analysis revealed the activation of cell division at the two later phases and in particular the induction of G1-specific genes in the maintenance phase. Furthermore, results point towards a specific demand for certain mineral nutrients starting in the recovery phase. PMID:24978694

A preliminary report on histological outcome of pulpotomy with endodontic biomaterials vs calcium hydroxide

PubMed Central

Peimani, Ali; Asgary, Saeed

2013-01-01

Objectives The purpose of the study was to evaluate human dental pulp response to pulpotomy with calcium hydroxide (CH), mineral trioxide aggregate (MTA), and calcium enriched mixture (CEM) cement. Materials and Methods A total of nine erupted third molars were randomly assigned to each pulpotomy group. The same clinician performed full pulpotomies and coronal restorations. The patients were followed clinically for six months; the teeth were then extracted and prepared for histological assessments. The samples were blindly assessed by an independent observer for pulp vitality, pulp inflammation, and calcified bridge formation. Results All patients were free of clinical signs/symptoms of pulpal/periradicular diseases during the follow up period. In CH group, one tooth had necrotic radicular pulp; other two teeth in this group had vital uninflamed pulps with complete dentinal bridge formation. In CEM cement and MTA groups all teeth had vital uninflamed radicular pulps. A complete dentinal bridge was formed beneath CEM cement and MTA in all roots. Odontoblast-like cells were present beneath CEM cement and MTA in all samples. Conclusions This study revealed that CEM cement and MTA were reliable endodontic biomaterials in full pulpotomy treatment. In contrast, the human dental pulp response to CH might be unpredictable. PMID:24303358

Regeneration of dental pulp by stem cells.

PubMed

Nakashima, M; Iohara, K

2011-07-01

Angiogenesis/vasculogenesis and neurogenesis are essential for pulp regeneration. Two subfractions of side-population (SP) cells, CD31(-)/CD146(-) SP cells and CD105(+) cells with angiogenic and neurogenic potential, were isolated by flow cytometry from canine dental pulp. In an experimental model of mouse hindlimb ischemia, transplantation of these cell populations resulted in an increase in blood flow, including high-density capillary formation. In a model of rat cerebral ischemia, stem cell transplantations enhanced neuronal regeneration and recovery from motor disability. Autologous transplantation of the CD31(-)/CD146(-) SP cells into an in vivo model of amputated pulp resulted in complete regeneration of pulp tissue with vascular and neuronal processes within 14 days. The transplanted cells expressed pro-angiogenic factors, implying trophic action on endothelial cells. Autologous transplantation of CD31(-)/CD146(-) SP cells or CD105(+) cells with stromal-cell-derived factor-1 (SDF-1) into root canals after whole pulp removal of mature teeth resulted in complete regeneration of pulp replete with nerves and vasculature by day 14, followed by dentin formation along the dentinal wall by day 35. Therefore, the potential utility of fractionated SP cells and CD105(+) cells in angiogenesis and neurogenesis was demonstrated by treatment of limb and cerebral ischemia following pulpotomy and pulpectomy.

The Physiology of Adventitious Roots1

PubMed Central

Steffens, Bianka; Rasmussen, Amanda

2016-01-01

Adventitious roots are plant roots that form from any nonroot tissue and are produced both during normal development (crown roots on cereals and nodal roots on strawberry [Fragaria spp.]) and in response to stress conditions, such as flooding, nutrient deprivation, and wounding. They are important economically (for cuttings and food production), ecologically (environmental stress response), and for human existence (food production). To improve sustainable food production under environmentally extreme conditions, it is important to understand the adventitious root development of crops both in normal and stressed conditions. Therefore, understanding the regulation and physiology of adventitious root formation is critical for breeding programs. Recent work shows that different adventitious root types are regulated differently, and here, we propose clear definitions of these classes. We use three case studies to summarize the physiology of adventitious root development in response to flooding (case study 1), nutrient deficiency (case study 2), and wounding (case study 3). PMID:26697895

Seismic imaging of a mid-lithospheric discontinuity beneath Ontong Java Plateau

NASA Astrophysics Data System (ADS)

Tharimena, Saikiran; Rychert, Catherine A.; Harmon, Nicholas

2016-09-01

Ontong Java Plateau (OJP) is a huge, completely submerged volcanic edifice that is hypothesized to have formed during large plume melting events ∼90 and 120 My ago. It is currently resisting subduction into the North Solomon trench. The size and buoyancy of the plateau along with its history of plume melting and current interaction with a subduction zone are all similar to the characteristics and hypothesized mechanisms of continent formation. However, the plateau is remote, and enigmatic, and its proto-continent potential is debated. We use SS precursors to image seismic discontinuity structure beneath Ontong Java Plateau. We image a velocity increase with depth at 28 ± 4 km consistent with the Moho. In addition, we image velocity decreases at 80 ± 5 km and 282 ± 7 km depth. Discontinuities at 60-100 km depth are frequently observed both beneath the oceans and the continents. However, the discontinuity at 282 km is anomalous in comparison to surrounding oceanic regions; in the context of previous results it may suggest a thick viscous root beneath OJP. If such a root exists, then the discontinuity at 80 km bears some similarity to the mid-lithospheric discontinuities (MLDs) observed beneath continents. One possibility is that plume melting events, similar to that which formed OJP, may cause discontinuities in the MLD depth range. Plume-plate interaction could be a mechanism for MLD formation in some continents in the Archean prior to the onset of subduction.

CAPRICE positively regulates stomatal formation in the Arabidopsis hypocotyl

PubMed Central

2008-01-01

In the Arabidopsis hypocotyl, stomata develop only from a set of epidermal cell files. Previous studies have identified several negative regulators of stomata formation. Such regulators also trigger non-hair cell fate in the root. Here, it is shown that TOO MANY MOUTHS (TMM) positively regulates CAPRICE (CPC) expression in differentiating stomaless-forming cell files, and that the CPC protein might move to the nucleus of neighbouring stoma-forming cells, where it promotes stomata formation in a redundant manner with TRIPTYCHON (TRY). Unexpectedly, the CPC protein was also localized in the nucleus and peripheral cytoplasm of hypocotyl fully differentiated epidermal cells, suggesting that CPC plays an additional role to those related to stomata formation. These results identify CPC and TRY as positive regulators of stomata formation in the embryonic stem, which increases the similarity between the genetic control of root hair and stoma cell fate determination. PMID:19513241

Interaction of Pratylenchus penetrans and Rhizoctonia fragariae in Strawberry Black Root Rot

PubMed Central

LaMondia, J. A.

2003-01-01

A split-root technique was used to examine the interaction between Pratylenchus penetrans and the cortical root-rotting pathogen Rhizoctonia fragariae in strawberry black root rot. Plants inoculated with both pathogens on the same half of a split-root crown had greater levels of root rot than plants inoculated separately or with either pathogen alone. Isolation of R. fragariae from field-grown roots differed with root type and time of sampling. Fungal infection of structural roots was low until fruiting, whereas perennial root colonization was high. Isolation of R. fragariae from feeder roots was variable, but was greater from feeder roots on perennial than from structural roots. Isolation of the fungus was greater from structural roots with nematode lesions than from non-symptomatic roots. Rhizoctonia fragariae was a common resident on the sloughed cortex of healthy perennial roots. From this source, the fungus may infect additional roots. The direct effects of lesion nematode feeding and movement are cortical cell damage and death. Indirect effects include discoloration of the endodermis and early polyderm formation. Perhaps weakened or dying cells caused directly or indirectly by P. penetrans are more susceptible to R. fragariae, leading to increased disease. PMID:19265969

Perforating internal root resorption repaired with mineral trioxide aggregate caused complete resolution of odontogenic sinus mucositis: a case report.

PubMed

Bendyk-Szeffer, Maja; Łagocka, Ryta; Trusewicz, Matylda; Lipski, Mariusz; Buczkowska-Radlińska, Jadwiga

2015-02-01

An extensive perforating internal root resorption accompanied by apical periodontitis and odontogenic sinus mucositis was detected on preoperative cone-beam computed tomographic scans in a first maxillary molar. After the chemomechanical debridement of the root canals, calcium hydroxide was placed as a temporary dressing for 7 days. Mineral trioxide aggregate was used to fill the perforation site with the aid of a surgical microscope. At the next visit, the root with the resorption defect was filled with warm vertical compaction of gutta-percha. A control cone-beam computed tomographic scan acquired 6 months after the endodontic treatment revealed complete resolution of the sinus retention cyst. Moreover, the patient's frequent otolaryngologic disturbances ceased. The tooth was functional with satisfactory clinical and radiographic results after 12 months. Based on the results of this case, successful repair of an extensive, perforating internal resorption with mineral trioxide aggregate may lead to complete resolution of apical periodontitis and maxillary sinus retention cyst. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Complete Genome Sequence of the Symbiotic Strain Bradyrhizobium icense LMTR 13T, Isolated from Lima Bean (Phaseolus lunatus) in Peru

PubMed Central

Rogel, Marco A.; Zúñiga-Dávila, Doris; Martínez-Romero, Esperanza

2018-01-01

ABSTRACT The complete genome sequence of Bradyrhizobium icense LMTR 13T, a root nodule bacterium isolated from the legume Phaseolus lunatus, is reported here. The genome consists of a circular 8,322,773-bp chromosome which codes for a large and novel symbiotic island as well as genes putatively involved in soil and root colonization. PMID:29519840

Coronectomy of the mandibular third molar: Respect for the inferior alveolar nerve.

PubMed

Kouwenberg, A J; Stroy, L P P; Rijt, E D Vree-V D; Mensink, G; Gooris, P J J

2016-05-01

The aim of this study was to evaluate the outcomes of coronectomy as an alternative surgical procedure to complete removal of the impacted mandibular third molar in patients with a suspected close relationship between the tooth root(s) and the mandibular canal. A total of 151 patients underwent coronectomy and were followed up with clinical examinations and panoramic radiographs for a minimum of 6 months after surgery. None of the patients exhibited inferior alveolar nerve injury. Eruption of the retained root(s) was more frequent in younger patients (18-35 years). Thirty-six patients (23.8%) exhibited insufficient growth of new bone in the alveolar defect, and 11.3% required a second surgical procedure to remove the root remnant(s). Our results indicate that coronectomy can be a reliable alternative to complete removal of the impacted mandibular third molar in patients exhibiting an increased risk of damage to the inferior alveolar nerve on panoramic radiographs. Copyright © 2016. Published by Elsevier Ltd.

Generation of alkali-free and high-proton concentration layer in a soda lime glass using non-contact corona discharge

NASA Astrophysics Data System (ADS)

Ikeda, Hiroshi; Sakai, Daisuke; Funatsu, Shiro; Yamamoto, Kiyoshi; Suzuki, Toshio; Harada, Kenji; Nishii, Junji

2013-08-01

Formation mechanisms of alkali-free and high-proton concentration surfaces were investigated for a soda lime glass using a corona discharge treatment under an atmospheric pressure. Protons produced by high DC voltage around an anode needle electrode were incorporated into a sodium ion site in the anode side glass. The sodium ion was swept away to the cathode side as a charge carrier. Then it was discharged. The precipitated sodium was transformed to a Na2CO3 powder when the surface contacted with air. The sodium ion in the glass surface layer of the anode side was replaced completely by protons. The concentration of OH groups in the layer was balanced with the amount of excluded sodium ions. The substitution reaction of sodium ions with protons tends to be saturated according to a square root function of time. The alkali depletion layer formation rate was affected by the large difference in mobility between sodium ions and protons in the glass.

Root-Knot and Cyst Nematodes Activate Procambium-Associated Genes in Arabidopsis Roots.

PubMed

Yamaguchi, Yasuka L; Suzuki, Reira; Cabrera, Javier; Nakagami, Satoru; Sagara, Tomomi; Ejima, Chika; Sano, Ryosuke; Aoki, Yuichi; Olmo, Rocio; Kurata, Tetsuya; Obayashi, Takeshi; Demura, Taku; Ishida, Takashi; Escobar, Carolina; Sawa, Shinichiro

2017-01-01

Developmental plasticity is one of the most striking features of plant morphogenesis, as plants are able to vary their shapes in response to environmental cues. Biotic or abiotic stimuli often promote organogenesis events in plants not observed under normal growth conditions. Root-knot nematodes (RKNs) are known to parasitize multiple species of rooting plants and to induce characteristic tissue expansion called galls or root-knots on the roots of their hosts by perturbing the plant cellular machinery. Galls contain giant cells (GCs) and neighboring cells, and the GCs are a source of nutrients for the parasitizing nematode. Highly active cell proliferation was observed in galls. However, the underlying mechanisms that regulate the symptoms triggered by the plant-nematode interaction have not yet been elucidated. In this study, we deciphered the molecular mechanism of gall formation with an in vitro infection assay system using RKN Meloidogyne incognita , and the model plant Arabidopsis thaliana. By taking advantages of this system, we performed next-generation sequencing-based transcriptome profiling, and found that the expression of procambium identity-associated genes were enriched during gall formation. Clustering analyses with artificial xylogenic systems, together with the results of expression analyses of the candidate genes, showed a significant correlation between the induction of gall cells and procambium-associated cells. Furthermore, the promoters of several procambial marker genes such as ATHB8 , TDR and WOX4 were activated not only in M. incognita -induced galls, but similarly in M. javanica induced-galls and Heterodera schachtii -induced syncytia. Our findings suggest that phytoparasitic nematodes modulate the host's developmental regulation of the vascular stem cells during gall formation.

Transposon Mutagenesis of the Plant-Associated Bacillus amyloliquefaciens ssp. plantarum FZB42 Revealed That the nfrA and RBAM17410 Genes Are Involved in Plant-Microbe-Interactions

PubMed Central

Dietel, Kristin; Beator, Barbara; Dolgova, Olga; Fan, Ben; Bleiss, Wilfrid; Ziegler, Jörg; Schmid, Michael; Hartmann, Anton; Borriss, Rainer

2014-01-01

Bacillus amyloliquefaciens ssp. plantarum FZB42 represents the prototype of Gram-positive plant growth promoting and biocontrol bacteria. In this study, we applied transposon mutagenesis to generate a transposon library, which was screened for genes involved in multicellular behavior and biofilm formation on roots as a prerequisite of plant growth promoting activity. Transposon insertion sites were determined by rescue-cloning followed by DNA sequencing. As in B. subtilis, the global transcriptional regulator DegU was identified as an activator of genes necessary for swarming and biofilm formation, and the DegU-mutant of FZB42 was found impaired in efficient root colonization. Direct screening of 3,000 transposon insertion mutants for plant-growth-promotion revealed the gene products of nfrA and RBAM_017140 to be essential for beneficial effects exerted by FZB42 on plants. We analyzed the performance of GFP-labeled wild-type and transposon mutants in the colonization of lettuce roots using confocal laser scanning microscopy. While the wild-type strain heavily colonized root surfaces, the nfrA mutant did not colonize lettuce roots, although it was not impaired in growth in laboratory cultures, biofilm formation and swarming motility on agar plates. The RBAM17410 gene, occurring in only a few members of the B. subtilis species complex, was directly involved in plant growth promotion. None of the mutant strains were affected in producing the plant growth hormone auxin. We hypothesize that the nfrA gene product is essential for overcoming the stress caused by plant response towards bacterial root colonization. PMID:24847778

Grapevine species from varied native habitats exhibit differences in embolism formation/repair associated with leaf gas exchange and root pressure

USDA-ARS?s Scientific Manuscript database

Drought induces xylem embolism formation, but grapevines can refill blocked conduits to restore transport capacity. It is unknown whether vulnerability to embolism formation and ability to repair differ among grapevine species. We analyzed in vivo embolism formation and repair using x-ray microtomog...

Silicon Promotes Exodermal Casparian Band Formation in Si-Accumulating and Si-Excluding Species by Forming Phenol Complexes

PubMed Central

Hinrichs, Martin; Specht, André; Waßmann, Friedrich; Schreiber, Lukas; Schenk, Manfred K.

2015-01-01

We studied the effect of Silicon (Si) on Casparian band (CB) development, chemical composition of the exodermal CB and Si deposition across the root in the Si accumulators rice and maize and the Si non-accumulator onion. Plants were cultivated in nutrient solution with and without Si supply. The CB development was determined in stained root cross-sections. The outer part of the roots containing the exodermis was isolated after enzymatic treatment. The exodermal suberin was transesterified with MeOH/BF3 and the chemical composition was measured using gas chromatography-mass spectroscopy (GC-MS) and flame ionization detector (GC-FID). Laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) was used to determine the Si deposition across root cross sections. Si promoted CB formation in the roots of Si-accumulator and Si non-accumulator species. The exodermal suberin was decreased in rice and maize due to decreased amounts of aromatic suberin fractions. Si did not affect the concentration of lignin and lignin-like polymers in the outer part of rice, maize and onion roots. The highest Si depositions were found in the tissues containing CB. These data along with literature were used to suggest a mechanism how Si promotes the CB development by forming complexes with phenols. PMID:26383862

NADPH Thioredoxin Reductase C Is Localized in Plastids of Photosynthetic and Nonphotosynthetic Tissues and Is Involved in Lateral Root Formation in Arabidopsis[W

PubMed Central

Kirchsteiger, Kerstin; Ferrández, Julia; Pascual, María Belén; González, Maricruz; Cejudo, Francisco Javier

2012-01-01

Plastids are organelles present in photosynthetic and nonphotosynthetic plant tissues. While it is well known that thioredoxin-dependent redox regulation is essential for leaf chloroplast function, little is known of the redox regulation in plastids of nonphotosynthetic tissues, which cannot use light as a direct source of reducing power. Thus, the question remains whether redox regulation operates in nonphotosynthetic plastid function and how it is integrated with chloroplasts for plant growth. Here, we show that NADPH-thioredoxin reductase C (NTRC), previously reported as exclusive to green tissues, is also expressed in nonphotosynthetic tissues of Arabidopsis thaliana, where it is localized to plastids. Moreover, we show that NTRC is involved in maintaining the redox homeostasis of plastids also in nonphotosynthetic organs. To test the relationship between plastids of photosynthetic and nonphotosynthetic tissues, transgenic plants were obtained with redox homeostasis restituted exclusively in leaves or in roots, through the expression of NTRC under the control of organ-specific promoters in the ntrc mutant. Our results show that fully functional root amyloplasts are not sufficient for root, or leaf, growth, but fully functional chloroplasts are necessary and sufficient to support wild-type rates of root growth and lateral root formation. PMID:22505729

NADPH thioredoxin reductase C is localized in plastids of photosynthetic and nonphotosynthetic tissues and is involved in lateral root formation in Arabidopsis.

PubMed

Kirchsteiger, Kerstin; Ferrández, Julia; Pascual, María Belén; González, Maricruz; Cejudo, Francisco Javier

2012-04-01

Plastids are organelles present in photosynthetic and nonphotosynthetic plant tissues. While it is well known that thioredoxin-dependent redox regulation is essential for leaf chloroplast function, little is known of the redox regulation in plastids of nonphotosynthetic tissues, which cannot use light as a direct source of reducing power. Thus, the question remains whether redox regulation operates in nonphotosynthetic plastid function and how it is integrated with chloroplasts for plant growth. Here, we show that NADPH-thioredoxin reductase C (NTRC), previously reported as exclusive to green tissues, is also expressed in nonphotosynthetic tissues of Arabidopsis thaliana, where it is localized to plastids. Moreover, we show that NTRC is involved in maintaining the redox homeostasis of plastids also in nonphotosynthetic organs. To test the relationship between plastids of photosynthetic and nonphotosynthetic tissues, transgenic plants were obtained with redox homeostasis restituted exclusively in leaves or in roots, through the expression of NTRC under the control of organ-specific promoters in the ntrc mutant. Our results show that fully functional root amyloplasts are not sufficient for root, or leaf, growth, but fully functional chloroplasts are necessary and sufficient to support wild-type rates of root growth and lateral root formation.

Endoscopic root canal treatment.

PubMed

Moshonov, Joshua; Michaeli, Eli; Nahlieli, Oded

2009-10-01

To describe an innovative endoscopic technique for root canal treatment. Root canal treatment was performed on 12 patients (15 teeth), using a newly developed endoscope (Sialotechnology), which combines an endoscope, irrigation, and a surgical microinstrument channel. Endoscopic root canal treatment of all 15 teeth was successful with complete resolution of all symptoms (6-month follow-up). The novel endoscope used in this study accurately identified all microstructures and simplified root canal treatment. The endoscope may be considered for use not only for preoperative observation and diagnosis but also for active endodontic treatment.

Novel scanning procedure enabling the vectorization of entire rhizotron-grown root systems

PubMed Central

2013-01-01

This paper presents an original spit-and-combine imaging procedure that enables the complete vectorization of complex root systems grown in rhizotrons. The general principle of the method is to (1) separate the root system into a small number of large pieces to reduce root overlap, (2) scan these pieces one by one, (3) analyze separate images with a root tracing software and (4) combine all tracings into a single vectorized root system. This method generates a rich dataset containing morphological, topological and geometrical information of entire root systems grown in rhizotrons. The utility of the method is illustrated with a detailed architectural analysis of a 20-day old maize root system, coupled with a spatial analysis of water uptake patterns. PMID:23286457

Novel scanning procedure enabling the vectorization of entire rhizotron-grown root systems.

PubMed

Lobet, Guillaume; Draye, Xavier

2013-01-04

: This paper presents an original spit-and-combine imaging procedure that enables the complete vectorization of complex root systems grown in rhizotrons. The general principle of the method is to (1) separate the root system into a small number of large pieces to reduce root overlap, (2) scan these pieces one by one, (3) analyze separate images with a root tracing software and (4) combine all tracings into a single vectorized root system. This method generates a rich dataset containing morphological, topological and geometrical information of entire root systems grown in rhizotrons. The utility of the method is illustrated with a detailed architectural analysis of a 20-day old maize root system, coupled with a spatial analysis of water uptake patterns.

Adventitious root formation in tree species: involvement of transcription factors.

PubMed

Legué, Valérie; Rigal, Adeline; Bhalerao, Rishikesh P

2014-06-01

Adventitious rooting is an essential step in the vegetative propagation of economically important horticultural and woody species. Populus has emerged as an experimental model for studying processes that are important in tree growth and development. It is highly useful for molecular genetic analysis of adventitious roots in trees. In this short review, we will highlight the recent progress made in the identification of transcription factors involved in the control of adventitious rooting in woody species. Their regulation will be discussed. © 2014 Scandinavian Plant Physiology Society.

Numerical simulation of the hair formation -modeling of hair cycle

NASA Astrophysics Data System (ADS)

Kajihara, Narumichi; Nagayama, Katsuya

2018-01-01

In the recent years, the fields of study of anti-aging, health and beauty, cosmetics, and hair diseases have attracted significant attention. In particular, human hair is considered to be an important aspect with regard to an attractive appearance. To this end, many workers have sought to understand the formation mechanism of the hair root. However, observing growth in the hair root is difficult, and a detailed mechanism of the process has not yet been elucidated. Hair repeats growth, retraction, and pause cycles (hair cycle) in a repetitive process. In the growth phase, hair is formed through processes of cell proliferation and differentiation (keratinization). During the retraction phase, hair growth stops, and during the resting period, hair fall occurs and new hair grows. This hair cycle is believed to affect the elongation rate, thickness, strength, and shape of hair. Therefore, in this study, we introduce a particle model as a new method to elucidate the unknown process of hair formation, and to model the hair formation process accompanying the proliferation and differentiation of the hair root cells in all three dimensions. In addition, to the growth period, the retraction and the resting periods are introduced to realize the hair cycle using this model.

A specific role of iron in promoting meristematic cell division during adventitious root formation.

PubMed

Hilo, Alexander; Shahinnia, Fahimeh; Druege, Uwe; Franken, Philipp; Melzer, Michael; Rutten, Twan; von Wirén, Nicolaus; Hajirezaei, Mohammad-Reza

2017-07-10

Adventitious root (AR) formation is characterized by a sequence of physiological and morphological processes and determined by external factors, including mineral nutrition, the impacts of which remain largely elusive. Morphological and anatomical evaluation of the effects of mineral elements on AR formation in leafy cuttings of Petunia hybrida revealed a striking stimulation by iron (Fe) and a promotive action of ammonium (NH4+). The optimal application period for these nutrients corresponded to early division of meristematic cells in the rooting zone and coincided with increased transcript levels of mitotic cyclins. Fe-localization studies revealed an enhanced allocation of Fe to the nuclei of meristematic cells in AR initials. NH4+ supply promoted AR formation to a lesser extent, most likely by favoring the availability of Fe. We conclude that Fe acts locally by promoting cell division in the meristematic cells of AR primordia. These results highlight a specific biological function of Fe in AR development and point to an unexploited importance of Fe for the vegetative propagation of plants from cuttings. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Through form to function: root hair development and nutrient uptake

NASA Technical Reports Server (NTRS)

Gilroy, S.; Jones, D. L.

2000-01-01

Root hairs project from the surface of the root to aid nutrient and water uptake and to anchor the plant in the soil. Their formation involves the precise control of cell fate and localized cell growth. We are now beginning to unravel the complexities of the molecular interactions that underlie this developmental regulation. In addition, after years of speculation, nutrient transport by root hairs has been demonstrated clearly at the physiological and molecular level, with evidence for root hairs being intense sites of H(+)-ATPase activity and involved in the uptake of Ca(2+), K(+), NH(4)(+), NO(3)(-), Mn(2+), Zn(2+), Cl(-) and H(2)PO(4)(-).

RcRR1, a Rosa canina type-A response regulator gene, is involved in cytokinin-modulated rhizoid organogenesis.

PubMed

Gao, Bin; Fan, Lusheng; Li, Xingxing; Yang, Huifang; Liu, Fengluan; Wang, Ling; Xi, Lin; Ma, Nan; Zhao, Liangjun

2013-01-01

In vitro, a new protocol of plant regeneration in rose was achieved via protocorm-like bodies (PLBs) induced from the root-like organs named rhizoids that developed from leaf explants. The development of rhizoids is a critical stage for efficient regeneration, which is triggered by exogenous auxin. However, the role of cytokinin in the control of organogenesis in rose is as yet uncharacterized. The aim of this study was to elucidate the molecular mechanism of cytokinin-modulated rhizoid formation in Rosa canina. Here, we found that cytokinin is a key regulator in the formation of rhizoids. Treatment with cytokinin reduced callus activity and significantly inhibited rhizoid formation in Rosa canina. We further isolated the full-length cDNA of a type-A response regulator gene of cytokinin signaling, RcRR1, from which the deduced amino acid sequence contained the conserved DDK motif. Gene expression analysis revealed that RcRR1 was differentially expressed during rhizoid formation and its expression level was rapidly up-regulated by cytokinin. In addition, the functionality of RcRR1 was tested in Arabidopsis. RcRR1 was found to be localized to the nucleus in GFP-RcRR1 transgenic plants and overexpression of RcRR1 resulted in increased primary root length and lateral root density. More importantly, RcRR1 overexpression transgenic plants also showed reduced sensitivity to cytokinin during root growth; auxin distribution and the expression of auxin efflux carriers PIN genes were altered in RcRR1 overexpression plants. Taken together, these results demonstrate that RcRR1 is a functional type-A response regulator which is involved in cytokinin-regulated rhizoid formation in Rosa canina.

RcRR1, a Rosa canina Type-A Response Regulator Gene, Is Involved in Cytokinin-Modulated Rhizoid Organogenesis

PubMed Central

Li, Xingxing; Yang, Huifang; Liu, Fengluan; Wang, Ling; Xi, Lin; Ma, Nan; Zhao, Liangjun

2013-01-01

In vitro, a new protocol of plant regeneration in rose was achieved via protocorm-like bodies (PLBs) induced from the root-like organs named rhizoids that developed from leaf explants. The development of rhizoids is a critical stage for efficient regeneration, which is triggered by exogenous auxin. However, the role of cytokinin in the control of organogenesis in rose is as yet uncharacterized. The aim of this study was to elucidate the molecular mechanism of cytokinin-modulated rhizoid formation in Rosa canina. Here, we found that cytokinin is a key regulator in the formation of rhizoids. Treatment with cytokinin reduced callus activity and significantly inhibited rhizoid formation in Rosa canina. We further isolated the full-length cDNA of a type-A response regulator gene of cytokinin signaling, RcRR1, from which the deduced amino acid sequence contained the conserved DDK motif. Gene expression analysis revealed that RcRR1 was differentially expressed during rhizoid formation and its expression level was rapidly up-regulated by cytokinin. In addition, the functionality of RcRR1 was tested in Arabidopsis. RcRR1 was found to be localized to the nucleus in GFP-RcRR1 transgenic plants and overexpression of RcRR1 resulted in increased primary root length and lateral root density. More importantly, RcRR1 overexpression transgenic plants also showed reduced sensitivity to cytokinin during root growth; auxin distribution and the expression of auxin efflux carriers PIN genes were altered in RcRR1 overexpression plants. Taken together, these results demonstrate that RcRR1 is a functional type-A response regulator which is involved in cytokinin-regulated rhizoid formation in Rosa canina. PMID:24009713

Nitrogen remobilisation facilitates adventitious root formation on reversible dark-induced carbohydrate depletion in Petunia hybrida.

PubMed

Zerche, Siegfried; Haensch, Klaus-Thomas; Druege, Uwe; Hajirezaei, Mohammad-Reza

2016-10-10

Adventitious root (AR) formation in axillary shoot tip cuttings is a crucial physiological process for ornamental propagation that is utilised in global production chains for young plants. In this process, the nitrogen and carbohydrate metabolisms of a cutting are regulated by its total nitrogen content (N t ), dark exposure during transport and irradiance levels at distinct production sites and phases through a specific plasticity to readjust metabolite pools. Here, we examined how elevated N t contents with a combined dark exposure of cuttings influence their internal N-pools including free amino acids and considered early anatomic events of AR formation as well as further root development in Petunia hybrida cuttings. Enhanced N t contents of unrooted cuttings resulted in elevated total free amino acid levels and in particular glutamate (glu) and glutamine (gln) in leaf and basal stem. N-allocation to mobile N-pools increased whereas the allocation to insoluble protein-N declined. A dark exposure of cuttings conserved initial N t and nitrate-N, while it reduced insoluble protein-N and increased soluble protein, amino- and amide-N. The increase of amino acids mainly comprised asparagine (asn), aspartate (asp) and arginine (arg) in the leaves, with distinct tissue specific responses to an elevated N supply. Dark exposure induced an early transient rise of asp followed by a temporary increase of glu. A strong positive N effect of high N t contents of cuttings on AR formation after 384 h was observed. Root meristematic cells developed at 72 h with a negligible difference for two N t levels. After 168 h, an enhanced N t accelerated AR formation and gave rise to first obvious fully developed roots while only meristems were formed with a low N t . However, dark exposure for 168 h promoted AR formation particularly in cuttings with a low N t to such an extent so that the benefit of the enhanced N t was almost compensated. Combined dark exposure and low N t of cuttings strongly reduced shoot growth during AR formation. The results indicate that both enhanced N t content and dark exposure of cuttings reinforced N signals and mobile N resources in the stem base facilitated by senescence-related proteolysis in leaves. Based on our results, a model of N mobilisation concomitant with carbohydrate depletion and its significance for AR formation is postulated.

Rules and Self-Organizing Properties of Post-embryonic Plant Organ Cell Division Patterns.

PubMed

von Wangenheim, Daniel; Fangerau, Jens; Schmitz, Alexander; Smith, Richard S; Leitte, Heike; Stelzer, Ernst H K; Maizel, Alexis

2016-02-22

Plants form new organs with patterned tissue organization throughout their lifespan. It is unknown whether this robust post-embryonic organ formation results from stereotypic dynamic processes, in which the arrangement of cells follows rigid rules. Here, we combine modeling with empirical observations of whole-organ development to identify the principles governing lateral root formation in Arabidopsis. Lateral roots derive from a small pool of founder cells in which some take a dominant role as seen by lineage tracing. The first division of the founders is asymmetric, tightly regulated, and determines the formation of a layered structure. Whereas the pattern of subsequent cell divisions is not stereotypic between different samples, it is characterized by a regular switch in division plane orientation. This switch is also necessary for the appearance of patterned layers as a result of the apical growth of the primordium. Our data suggest that lateral root morphogenesis is based on a limited set of rules. They determine cell growth and division orientation. The organ-level coupling of the cell behavior ensures the emergence of the lateral root's characteristic features. We propose that self-organizing, non-deterministic modes of development account for the robustness of plant organ morphogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bacillus subtilis Early Colonization of Arabidopsis thaliana Roots Involves Multiple Chemotaxis Receptors.

PubMed

Allard-Massicotte, Rosalie; Tessier, Laurence; Lécuyer, Frédéric; Lakshmanan, Venkatachalam; Lucier, Jean-François; Garneau, Daniel; Caudwell, Larissa; Vlamakis, Hera; Bais, Harsh P; Beauregard, Pascale B

2016-11-29

Colonization of plant roots by Bacillus subtilis is mutually beneficial to plants and bacteria. Plants can secrete up to 30% of their fixed carbon via root exudates, thereby feeding the bacteria, and in return the associated B. subtilis bacteria provide the plant with many growth-promoting traits. Formation of a biofilm on the root by matrix-producing B. subtilis is a well-established requirement for long-term colonization. However, we observed that cells start forming a biofilm only several hours after motile cells first settle on the plant. We also found that intact chemotaxis machinery is required for early root colonization by B. subtilis and for plant protection. Arabidopsis thaliana root exudates attract B. subtilis in vitro, an activity mediated by the two characterized chemoreceptors, McpB and McpC, as well as by the orphan receptor TlpC. Nonetheless, bacteria lacking these chemoreceptors are still able to colonize the root, suggesting that other chemoreceptors might also play a role in this process. These observations suggest that A. thaliana actively recruits B. subtilis through root-secreted molecules, and our results stress the important roles of B. subtilis chemoreceptors for efficient colonization of plants in natural environments. These results demonstrate a remarkable strategy adapted by beneficial rhizobacteria to utilize carbon-rich root exudates, which may facilitate rhizobacterial colonization and a mutualistic association with the host. Bacillus subtilis is a plant growth-promoting rhizobacterium that establishes robust interactions with roots. Many studies have now demonstrated that biofilm formation is required for long-term colonization. However, we observed that motile B. subtilis mediates the first contact with the roots. These cells differentiate into biofilm-producing cells only several hours after the bacteria first contact the root. Our study reveals that intact chemotaxis machinery is required for the bacteria to reach the root. Many, if not all, of the B. subtilis 10 chemoreceptors are involved in the interaction with the plant. These observations stress the importance of root-bacterium interactions in the B. subtilis lifestyle. Copyright © 2016 Allard-Massicotte et al.

Initiation and elongation of lateral roots in Lactuca sativa

NASA Technical Reports Server (NTRS)

Zhang, N.; Hasenstein, K. H.

1999-01-01

Lactuca sativa cv. Baijianye seedlings do not normally produce lateral roots, but removal of the root tip or application of auxin, especially indole-butyric acid, triggered the formation of lateral roots. Primordia initiated within 9 h and were fully developed after 24 h by activating the pericycle cells opposite the xylem pole. The pericycle cells divided asymmetrically into short and long cells. The short cells divided further to form primordia. The effect of root tip removal and auxin application was reversed by 6-benzylaminopurine at concentrations >10(-8) M. The cytokinin oxidase inhibitor N1-(2chloro4pyridyl)-N2-phenylurea also suppressed auxin-induced lateral rooting. The elongation of primary roots was promoted by L-alpha-(2-aminoethoxyvinyl) glycine and silver ions, but only the latter enhanced elongation of lateral roots. The data indicate that the induction of lateral roots is controlled by basipetally moving cytokinin and acropetally moving auxin. Lateral roots appear to not produce ethylene.

Periapical status and quality of root fillings in a selected adult Riga population.

PubMed

Jersa, Ilana; Kundzina, Rita

2013-01-01

The aim of the study was to assess the prevalence of apical periodontitis and quality of root canal fillings in an adult Riga subpopulation. Panoramic radiographs of Latvian adults 35-44 year old attending a private dental clinic for the first time during the period of 2004-2008 were included in the study. Totally, 312 out of 1248 panoramic radiographs were randomly selected and examined for periapical conditions and endodontic treatment quality. The technical quality of root fillings was evaluated in terms of length in relation to the root apex and lateral adaptation to the canal wall. The periapical status was assessed using the PAI index. The data were analyzed using SPSS 14 computer software program. Statistical significance was assessed by the chi-squared (Pearson's) test. Out of the 312 individuals examined 224 (72%) had one or more teeth with apical periodontitis (PAI 3-5) and 272 individuals (87%) had one or more endodontically treated teeth. Amongst 7065 teeth evaluated 1255 (18%) were endodontically treated. Only 285 teeth (23%) of the root canal treated teeth were with complete root canal fillings. There was a statistically significant relationship between quality of root canal fillings and apical periodontitis (p<0.0001). In teeth with complete fillings only 15% were with apical periodontitis, but apical periodontitis were detected in 342 teeth (35%) with incomplete root fillings. The results from this study indicates a high prevalence of apical periodontitis and low quality of root fillings in a selected adult Riga population.

Micro-computed Tomography versus the Cross-sectioning Method to Evaluate Dentin Defects Induced by Different Mechanized Instrumentation Techniques.

PubMed

Stringheta, Carolina Pessoa; Pelegrine, Rina Andréa; Kato, Augusto Shoji; Freire, Laila Gonzales; Iglecias, Elaine Faga; Gavini, Giulio; Bueno, Carlos Eduardo da Silveira

2017-12-01

The objective of this study was to compare the methods of micro-computed tomography (micro-CT) and cross-sectioning followed by stereomicroscopy in assessing dentinal defects after instrumentation with different mechanized systems. Forty mesial roots of mandibular molars were scanned and divided into 4 groups (n = 10): Group R, Reciproc; Group PTN, ProTaper Next; Group WOG, WaveOne Gold; Group PDL, ProDesign Logic. After instrumentation, the roots were once again submitted to a micro-CT scan, and then sectioned at 3, 6, and 9 mm from the apex, and assessed for the presence of complete and incomplete dentinal defects under a stereomicroscope. The nonparametric Kruskal-Wallis, Friedman, and Wilcoxon tests were used in the statistical analysis. The study used a significance level of 5%. The total number of defects observed by cross-sectioning followed by stereomicroscopy was significantly higher than that observed by micro-CT, in all of the experimental groups (P ≤ .05). All of the defects identified in the postoperative period were already present in the corresponding preoperative period. There was no significant difference among the instrumentation systems as to the median numbers of defects, for either cross-sectioning followed by stereomicroscopy or micro-CT, at all the root levels (P > .05). In the micro-CT analysis, no significant difference was found between the median numbers of pre- and postinstrumentation defects, regardless of the instrumentation system (P > .05). None of the evaluated instrumentation systems led to the formation of new dentin defects. All of the defects identified in the stereomicroscopic analysis were already present before instrumentation, or were absent at both time points in the micro-CT analysis, indicating that the formation of new defects resulted from the sectioning procedure performed before stereomicroscopy and not from instrumentation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Root coverage of a previously restored tooth. A case report with a 7-year follow-up

PubMed Central

Corsair, Alexander

2009-01-01

This case report describes the treatment of a maxillary canine that had 4 mm of marginal gingival recession. The exposed root had been previously restored with a composite class 5 restoration. The restoration was removed and the root planed and demineralized. The root was then covered by a subepithelial connective tissue graft harvested from the palate. The flap was coronally positioned to completely cover the graft and exposed root. The healing was photographed post-operatively at one month, six months, and seven years. Root coverage increased to 100% after seven years. The zone of attached gingiva also increased. PMID:23674903

Root coverage of a previously restored tooth. A case report with a 7-year follow-up.

PubMed

Corsair, Alexander

2009-01-01

This case report describes the treatment of a maxillary canine that had 4 mm of marginal gingival recession. The exposed root had been previously restored with a composite class 5 restoration. The restoration was removed and the root planed and demineralized. The root was then covered by a subepithelial connective tissue graft harvested from the palate. The flap was coronally positioned to completely cover the graft and exposed root. The healing was photographed post-operatively at one month, six months, and seven years. Root coverage increased to 100% after seven years. The zone of attached gingiva also increased.

Autotransplantation and Orthodontic Treatment after Maxillary Central Incisor Region Trauma: A 13-Year Follow-Up Case Report Study.

PubMed

Piroozmand, Farzad; Hessari, Hossein; Shirazi, Mohsen; Khazaei, Pegah

2018-01-01

The anterior maxilla is the most prone region to the trauma during childhood, and tooth loss sometimes happens due to trauma. Replacing the missing teeth has always been one of the dentists' challenges in children and adolescents, since their dentofacial growth is not complete. Autotransplantation of mandibular premolars with two-thirds or three-quarters of root formation provides the best prognosis for the tooth survival. This case report describes the management of a 10-year-old boy suffering a severe dental injury who received the autotransplantation of the premolars from mandible to restore the space caused by trauma in maxillary central incisor region and a 13-year follow-up of the autotransplantation.

[The mechanism of root hair development and molecular regulation in plants].

PubMed

Wang, Yue-Ping; Li, Ying-Hui; Guan, Rong-Xia; Liu, Zhang-Xiong; Chen, Xiong-Ting; Chang, Ru-Zhen; Qiu, Li-Juan

2007-04-01

The formation of the root epidermis in Arabidopsis thaliana provides a simple model to study mechanisms underlying patterning in plants. Root hair increases the root surface area and effectively increases the root diameter, so root hair is thought to aid plants in nutrient uptake, anchorage and microbe interactions. The determination of root hair development has two types, lateral inhibition with feedback and position-dependent pattern of cell differentiation. The initiation and development of root hair in Arabidopsis provide a simple and efficacious model for the study of cell fate determination in plants. Molecular genetic studies identify a suite of putative transcription factors which regulate the epidermal cell pattern. The homeodomain protein GLABRA2 (GL2), R2R3 MYB-type transcription factor WEREWOLF (WER) and WD-repeat protein TRANSPARENTT TESTA GLABRA (TTG) are required for specification of non-hair cell type. The CAPRICE (CPC) and TRYPTICHON (TRY) are involved in specifying the hair cell fate.

A gradient of endogenous calcium forms in mucilage of graviresponding roots of Zea mays

NASA Technical Reports Server (NTRS)

Moore, R.; Fondren, W. M.

1988-01-01

Agar blocks that contacted the upper sides of tips of horizontally-oriented roots of Zea mays contain significantly less calcium (Ca) than blocks that contacted the lower sides of such roots. This gravity-induced gradient of Ca forms prior to the onset of gravicurvature, and does not form across tips of vertically-oriented roots or roots of agravitropic mutants. These results indicate that (1) Ca can be collected from mucilage of graviresponding roots, (2) gravity induces a downward movement of endogenous Ca in mucilage overlying the root tip, (3) this gravity-induced gradient of Ca does not form across tips of agravitropic roots, and (4) formation of a Ca gradient is not a consequence of gravicurvature. These results are consistent with gravity-induced movement of Ca being a trigger for subsequent redistribution of growth effectors (e.g. auxin) that induce differential growth and gravicurvature.

Strigolactone Levels in Dicot Roots Are Determined by an Ancestral Symbiosis-Regulated Clade of the PHYTOENE SYNTHASE Gene Family

PubMed Central

Stauder, Ron; Welsch, Ralf; Camagna, Maurizio; Kohlen, Wouter; Balcke, Gerd U.; Tissier, Alain; Walter, Michael H.

2018-01-01

Strigolactones (SLs) are apocarotenoid phytohormones synthesized from carotenoid precursors. They are produced most abundantly in roots for exudation into the rhizosphere to cope with mineral nutrient starvation through support of root symbionts. Abscisic acid (ABA) is another apocarotenoid phytohormone synthesized in roots, which is involved in responses to abiotic stress. Typically low carotenoid levels in roots raise the issue of precursor supply for the biosynthesis of these two apocarotenoids in this organ. Increased ABA levels upon abiotic stress in Poaceae roots are known to be supported by a particular isoform of phytoene synthase (PSY), catalyzing the rate-limiting step in carotenogenesis. Here we report on novel PSY3 isogenes from Medicago truncatula (MtPSY3) and Solanum lycopersicum (SlPSY3) strongly expressed exclusively upon root interaction with symbiotic arbuscular mycorrhizal (AM) fungi and moderately in response to phosphate starvation. They belong to a widespread clade of conserved PSYs restricted to dicots (dPSY3) distinct from the Poaceae-PSY3s involved in ABA formation. An ancient origin of dPSY3s and a potential co-evolution with the AM symbiosis is discussed in the context of PSY evolution. Knockdown of MtPSY3 in hairy roots of M. truncatula strongly reduced SL and AM-induced C13 α-ionol/C14 mycorradicin apocarotenoids. Inhibition of the reaction subsequent to phytoene synthesis revealed strongly elevated levels of phytoene indicating induced flux through the carotenoid pathway in roots upon mycorrhization. dPSY3 isogenes are coregulated with upstream isogenes and downstream carotenoid cleavage steps toward SLs (D27, CCD7, CCD8) suggesting a combined carotenoid/apocarotenoid pathway, which provides “just in time”-delivery of precursors for apocarotenoid formation. PMID:29545815

Trans-Golgi network localized small GTPase RabA1d is involved in cell plate formation and oscillatory root hair growth.

PubMed

Berson, Tobias; von Wangenheim, Daniel; Takáč, Tomáš; Šamajová, Olga; Rosero, Amparo; Ovečka, Miroslav; Komis, George; Stelzer, Ernst H K; Šamaj, Jozef

2014-09-27

Small Rab GTPases are important regulators of vesicular trafficking in plants. AtRabA1d, a member of the RabA1 subfamily of small GTPases, was previously found in the vesicle-rich apical dome of growing root hairs suggesting a role during tip growth; however, its specific intracellular localization and role in plants has not been well described. The transient expression of 35S::GFP:RabA1d construct in Allium porrum and Nicotiana benthamiana revealed vesicular structures, which were further corroborated in stable transformed Arabidopsis thaliana plants. GFP-RabA1d colocalized with the trans-Golgi network marker mCherry-VTI12 and with early FM4-64-labeled endosomal compartments. Late endosomes and endoplasmic reticulum labeled with FYVE-DsRed and ER-DsRed, respectively, were devoid of GFP-RabA1d. The accumulation of GFP-RabA1d in the core of brefeldin A (BFA)-induced-compartments and the quantitative upregulation of RabA1d protein levels after BFA treatment confirmed the association of RabA1d with early endosomes/TGN and its role in vesicle trafficking. Light-sheet microscopy revealed involvement of RabA1d in root development. In root cells, GFP-RabA1d followed cell plate expansion consistently with cytokinesis-related vesicular trafficking and membrane recycling. GFP-RabA1d accumulated in disc-like structures of nascent cell plates, which progressively evolved to marginal ring-like structures of the growing cell plates. During root hair growth and development, GFP-RabA1d was enriched at root hair bulges and at the apical dome of vigorously elongating root hairs. Importantly, GFP-RabA1d signal intensity exhibited an oscillatory behavior in-phase with tip growth. Progressively, this tip localization dissapeared in mature root hairs suggesting a link between tip localization of RabA1d and root hair elongation. Our results support a RabA1d role in events that require vigorous membrane trafficking. RabA1d is located in early endosomes/TGN and is involved in vesicle trafficking. RabA1d participates in both cell plate formation and root hair oscillatory tip growth. The specific GFP-RabA1d subcellular localization confirms a correlation between its specific spatio-temporal accumulation and local vesicle trafficking requirements during cell plate and root hair formation.

Complete Genome Sequence of the Symbiotic Strain Bradyrhizobium icense LMTR 13T, Isolated from Lima Bean (Phaseolus lunatus) in Peru.

PubMed

Ormeño-Orrillo, Ernesto; Rogel, Marco A; Zúñiga-Dávila, Doris; Martínez-Romero, Esperanza

2018-03-08

The complete genome sequence of Bradyrhizobium icense LMTR 13 T , a root nodule bacterium isolated from the legume Phaseolus lunatus , is reported here. The genome consists of a circular 8,322,773-bp chromosome which codes for a large and novel symbiotic island as well as genes putatively involved in soil and root colonization. Copyright © 2018 Ormeño-Orrillo et al.

Cadmium induces hypodermal periderm formation in the roots of the monocotyledonous medicinal plant Merwilla plumbea

PubMed Central

Lux, Alexander; Vaculík, Marek; Martinka, Michal; Lišková, Desana; Kulkarni, Manoj G.; Stirk, Wendy A.; Van Staden, Johannes

2011-01-01

Background and Aims Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminated with metals from mining activities, the danger of human intoxication exists. An experiment with plants exposed to cadmium (Cd) was performed to investigate the response of M. plumbea to this heavy metal, its uptake and translocation to plant organs and reaction of root tissues. Methods Plants grown from seeds were cultivated in controlled conditions. Hydroponic cultivation is not suitable for this species as roots do not tolerate aquatic conditions, and additional stress by Cd treatment results in total root growth inhibition and death. After cultivation in perlite the plants exposed to 1 and 5 mg Cd L−1 in half-strength Hoagland's solution were compared with control plants. Growth parameters were evaluated, Cd content was determined by inductively coupled plasma mass spectroscopy (ICP-MS) and root structure was investigated using various staining procedures, including the fluorescent stain Fluorol yellow 088 to detect suberin deposition in cell walls. Key Results The plants exposed to Cd were significantly reduced in growth. Most of the Cd taken up by plants after 4 weeks cultivation was retained in roots, and only a small amount was translocated to bulbs and leaves. In reaction to higher Cd concentrations, roots developed a hypodermal periderm close to the root tip. Cells produced by cork cambium impregnate their cell walls by suberin. Conclusions It is suggested that the hypodermal periderm is developed in young root parts in reaction to Cd toxicity to protect the root from radial uptake of Cd ions. Secondary meristems are usually not present in monocotyledonous species. Another interpretation explaining formation of protective suberized layers as a result of periclinal divisions of the hypodermis is discussed. This process may represent an as yet unknown defence reaction of roots when exposed to elemental stress. PMID:21118841

Demonstrations at School Level of the Effects of IAA

ERIC Educational Resources Information Center

Falk, Peter

1973-01-01

Describes demonstrations suitable for secondary school biology classes relating to the effects of the hormone IAA on plant growth. Demonstrations illustrate how hormone treatments affect stem elongation, callus formation, inhibition of axillary buds, stimulation of secondary growth and initiation of adventitious root development, root elongation,…

Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images

NASA Astrophysics Data System (ADS)

Minamino, Takuya; Mine, Atsushi; Matsumoto, Mariko; Sugawa, Yoshihiko; Kabetani, Tomoshige; Higashi, Mami; Kawaguchi, Asuka; Ohmi, Masato; Awazu, Kunio; Yatani, Hirofumi

2015-10-01

No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root.

Biochemical Composition Suggests Different Roles of Leaf Litter and Fine Roots in Soil Carbon Formation

NASA Astrophysics Data System (ADS)

Xia, M.; Pregitzer, K. S.; Talhelm, A. F.

2012-12-01

Plant litter is a major source of soil organic carbon (C). This litter is not homogenous, but instead primarily composed of fine root and leaf litter that adapted to different physiological functions. These unique functions suggest that root and leaf litter likely have different biochemical traits, and thus different decomposition patterns. However, few studies have compared their substrate quality and contributions to soil C. Also, much less attention has been given to fine roots although they can represent a substantial litter production. Here we hypothesize that 1) leaf litter and fine roots have different substrate quality as they are highly different in biochemical composition; 2) the biochemical composition of leaf litter and fine roots responds differently to the simulated nitrogen (N) deposition. To test these hypotheses, we collected leaf litter and fine roots of Acer saccharum (the dominant species in the northern temperate ecosystems we studied) in both ambient and N addition treatment plots at four sites of Michigan N deposition gradient study. We quantified ten biochemical components thought to be important on decomposition. Strikingly, we found a consistently three-fold higher lignin concentration in fine roots than that in leaf litter (P< 0.01). On average, lignin concentration of fine roots was 45.4±0.3% while that of leaf litter was 13.5±0.2%. Lignin has been considered highly recalcitrant and hypothesized as the major precursor of humus substance. Condensed tannin (CT) concentration in fine roots (13.13±0.51%) was also substantially higher than that in leaf litter (P< 0.01, 4.63±0.42 %). Tissue CT can inhibit litter decay by both precipitating proteins and by having antimicrobial properties. In contrast, fine roots exhibited lower concentrations of non-structural carbohydrates (NSC), soluble phenolics, and holocellulose (hemicelluloses & cellulose) than leaf litter (P< 0.01). These components are considered more easily accessible, and may stimulate the decay of lignin by providing required energy. Therefore, fine roots of Acer saccharum have a relatively recalcitrant nature based on their distinct biochemical composition, suggesting fine roots may be the major driver of soil carbon formation in the ecosystems we studied. Litter type and N addition had significant interactions on lignin, holocellulose, and NSC (P< 0.05), indicating these traits of different litter types respond differently to N addition. In leaf litter, the concentrations of lignin, NSC, and bound CT were affected by N addition (P< 0.05). By contrast, N addition only reduced the soluble protein concentration in fine roots (P< 0.05). Hence, substrate quality of leaf litter and fine roots responds differently to the simulated N deposition, and may eventually lead to different responses in decomposition pattern. This is one of few studies comparing the detailed biochemical profile of leaf litter and fine roots in a dominant tree species. Different biochemical traits of fine roots and leaf litter may reflect the different specializations for their physiological functions. This work highlights the importance of fine root in the soil carbon formation due to its recalcitrant nature, and emphasizes the necessity of differentiating the responses of leaf litter and fine root decompositions to environmental changes when modeling biogeochemical cycles.

Developmental role of phenylalanine-ammonia-lyase (PAL) and cinnamate 4-hydroxylase (C4H) genes during adventitious rooting of Juglans regia L. microshoots.

PubMed

Cheniany, Monireh; Ganjeali, Ali

2016-12-01

Phenylalanine-ammonia-lyase and cinnamate-4-hydroxylase play important role in the phenylpropanoid pathway, which produces many biologically important secondary metabolites participating in normal plant development. Flavonol quercetin is the main representant of these compounds that has been identified in numerous Juglans spp. In this survey, the developmental expression patterns of PAL and C4H genes during in vitro rooting of two walnut cultivars 'Sunland' and 'Howard' was examined by RT-PCR. To understand the potential role in rooting, the changing pattern of endogenous content of quercetin was also analyzed by HPLC. The 'Sunland' with better capacity to root had more quercetin content during the "inductive phase" of rooting than 'Howard'. In each cultivar, the level of PAL transcripts showed the same behavior with the changing patterns of quercetin during root formation of microshoots. The positive correlation between the changes of quercetin and PAL-mRNA indicated that PAL gene may have an immediate effect on flavonoid pathway metabolites including quercetin. Although the behavioral change of C4H expression was similar in both cultivars during root formation (with significantly more level for 'Howard'), it was not coincide with the changes of quercerin concentrations. Our results showed that C4H function is important for the normal development, but its transcriptional regulation does not correlate with quercetin as an efficient phenolic compound for walnut rhizogenesis.

Jasmonates act positively in adventitious root formation in petunia cuttings.

PubMed

Lischweski, Sandra; Muchow, Anne; Guthörl, Daniela; Hause, Bettina

2015-09-22

Petunia is a model to study the process of adventitious root (AR) formation on leafy cuttings. Excision of cuttings leads to a transient increase in jasmonates, which is regarded as an early, transient and critical event for rooting. Here, the role of jasmonates in AR formation on petunia cuttings has been studied by a reverse genetic approach. To reduce the endogenous levels of jasmonates, transgenic plants were generated expressing a Petunia hybrida ALLENE OXIDE CYCLASE (PhAOC)-RNAi construct. The transgenic plants exhibited strongly reduced PhAOC transcript and protein levels as well as diminished accumulation of cis-12-oxo-phytodienoic acid, jasmonic acid and jasmonoyl-isoleucine after wounding in comparison to wild type and empty vector expressing plants. Reduced levels of endogenous jasmonates resulted in formation of lower numbers of ARs. However, this effect was not accompanied by altered levels of auxin and aminocyclopropane carboxylate (ACC, precursor of ethylene) or by impaired auxin and ethylene-induced gene expression. Neither activity of cell-wall invertases nor accumulation of soluble sugars was altered by jasmonate deficiency. Diminished numbers of AR in JA-deficient cuttings suggest that jasmonates act as positive regulators of AR formation in petunia wild type. However, wound-induced rise in jasmonate levels in petunia wild type cuttings seems not to be causal for increased auxin and ethylene levels and for sink establishment.

Endodontic Microsurgical Treatment of a Three-rooted Mandibular First Molar with Separate Distolingual Root: Report of One Case.

PubMed

Wang, Han Guo; Xu, Ning; Yu, Qing

The separate distolingual (DL) roots of three-rooted mandibular first molars are thought to be too difficult for performing apical surgery. This article represents microsurgical treatment of a three-rooted mandibular first molar with a separate DL root. The procedure includes incision and flap retraction, osteotomy, apicoectomy, retropreparation and retrofilling of the root canal, using micro instruments, ultrasonic retrotips and mineral trioxide aggregate (MTA) under a dental operating microscope. Two mm in length of apical root resection, 2 mm in depth of root canal retropreparation with a personalised ultrasonic retrotip, and 2 mm in length of retrofilling with MTA are the key points for accomplishment of apical surgery on separate DL roots. The case was followed up for 15 months after surgery. Clinical and radiographic examinations revealed complete healing of periapical tissue. Separate DL roots of three-rooted mandibular first molars can be treated by endodontic microsurgery with modifications from standard protocol.

Succinoglycan Is Required for Initiation and Elongation of Infection Threads during Nodulation of Alfalfa by Rhizobium meliloti

PubMed Central

Cheng, Hai-Ping; Walker, Graham C.

1998-01-01

Rhizobium meliloti Rm1021 must be able to synthesize succinoglycan in order to invade successfully the nodules which it elicits on alfalfa and to establish an effective nitrogen-fixing symbiosis. Using R. meliloti cells that express green fluorescent protein (GFP), we have examined the nature of the symbiotic deficiency of exo mutants that are defective or altered in succinoglycan production. Our observations indicate that an exoY mutant, which does not produce succinoglycan, is symbiotically defective because it cannot initiate the formation of infection threads. An exoZ mutant, which produces succinoglycan without the acetyl modification, forms nitrogen-fixing nodules on plants, but it exhibits a reduced efficiency in the initiation and elongation of infection threads. An exoH mutant, which produces symbiotically nonfunctional high-molecular-weight succinoglycan that lacks the succinyl modification, cannot form extended infection threads. Infection threads initiate at a reduced rate and then abort before they reach the base of the root hairs. Overproduction of succinoglycan by the exoS96::Tn5 mutant does not reduce the efficiency of infection thread initiation and elongation, but it does significantly reduce the ability of this mutant to colonize the curled root hairs, which is the first step of the invasion process. The exoR95::Tn5 mutant, which overproduces succinoglycan to an even greater extent than the exoS96::Tn5 mutant, has completely lost its ability to colonize the curled root hairs. These new observations lead us to propose that succinoglycan is required for both the initiation and elongation of infection threads during nodule invasion and that excess production of succinoglycan interferes with the ability of the rhizobia to colonize curled root hairs. PMID:9748453

[Modern aortic surgery in Marfan syndrome--2011].

PubMed

Kallenbach, K; Schwill, S; Karck, M

2011-09-01

Marfan syndrome is a hereditary disease with a prevalence of 2-3 in 10,000 births, leading to a fibrillin connective tissue disorder with manifestations in the skeleton, eye, skin, dura mater and in particular the cardiovascular system. Since other syndromes demonstrate similar vascular manifestations, but therapy may differ significantly, diagnosis should be established using the revised Ghent nosology in combination with genotypic analysis in specialized Marfan centres. The formation of aortic root aneurysms with the subsequent risk of acute aortic dissection type A (AADA) or aortic rupture limits life expectancy in patients with Marfan syndrome. Therefore, prophylactic replacement of the aortic root needs to be performed before the catastrophic event of AADA can occur. The goal of surgery is the complete resection of pathological aortic tissue. This can be achieved with excellent results by using a (mechanically) valved conduit that replaces both the aortic valve and the aortic root (Bentall operation). However, the need for lifelong anticoagulation with Coumadin can be avoided using the aortic valve sparing reimplantation technique according to David. The long-term durability of the reconstructed valve is favourable, and further technical improvements may improve longevity. Although results of prospective randomised long-term studies comparing surgical techniques are lacking, the David operation has become the surgical method of choice for aortic root aneurysms, not only at the Heidelberg Marfan Centre. Replacement of the aneurysmal dilated aortic arch is performed under moderate hypothermic circulatory arrest combined with antegrade cerebral perfusion using a heart-lung machine, which we also use in thoracic or thoracoabdominal aneurysms. Close post-operative follow-up in a Marfan centre is pivotal for the early detection of pathological changes on the diseased aorta.

Autotransplantation of third molars with completely formed roots into surgically created sockets and fresh extraction sockets: a 10-year comparative study.

PubMed

Yu, H J; Jia, P; Lv, Z; Qiu, L X

2017-04-01

The aim of this study was to analyze and compare the long-term clinical outcomes of mature third molar autotransplantation in surgically created sockets and fresh extraction sockets with regard to survival and functional success rates. A total of 65 third molars with completely formed roots were autotransplanted in 60 patients (average age 33.1 years). Thirty-six of the teeth were autotransplanted into surgically created sockets with or without guided bone regeneration (GBR; delayed autotransplantation), while 29 were autotransplanted into fresh extraction sockets (immediate autotransplantation; control group). All patients underwent annual clinical and radiographic examinations (average follow-up 9.9 years, range 7-13 years). The survival rates for the control, GBR, and no GBR groups were 93.1%, 95.2%, and 80.0%, respectively, with no significant differences among the groups. There were no statistically significant differences among the groups with regard to the frequency of inflammatory root resorption or root ankylosis. Age did not influence the clinical outcomes. These results suggest that the autotransplantation of third molars with completely formed roots is effective in both surgically created and fresh extraction sockets and provides a high long-term success rate if cases are selected and treated appropriately. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Plant Hormones: How They Affect Root Formation.

ERIC Educational Resources Information Center

Reinhard, Diana Hereda

This science study aid, produced by the U.S. Department of Agriculture, includes a series of plant rooting activities for secondary science classes. The material in the pamphlet is written for students and includes background information on plant hormones, a vocabulary list, and five learning activities. Objectives, needed materials, and…

Role of motor-evoked potential monitoring in conjunction with temporary clipping of spinal nerve roots in posterior thoracic spine tumor surgery.

PubMed

Eleraky, Mohammed A; Setzer, Matthias; Papanastassiou, Ioannis D; Baaj, Ali A; Tran, Nam D; Katsares, Kiesha M; Vrionis, Frank D

2010-05-01

The vascular supply of the thoracic spinal cord depends on the thoracolumbar segmental arteries. Because of the small size and ventral course of these arteries in relation to the dorsal root ganglion and ventral root, they cannot be reliably identified during surgery by anatomic or morphologic criteria. Sacrificing them will most likely result in paraplegia. The goal of this study was to evaluate a novel method of intraoperative testing of a nerve root's contribution to the blood supply of the thoracic spinal cord. This is a clinical retrospective study of 49 patients diagnosed with thoracic spine tumors. Temporary nerve root clipping combined with motor-evoked potential (MEP) and somatosensory-evoked potential (SSEP) monitoring was performed; additionally, postoperative clinical evaluation was done and reported in all cases. All cases were monitored by SSEP and MEPs. The nerve root to be sacrificed was temporarily clipped using standard aneurysm clips, and SSEP/MEP were assessed before and after clipping. Four nerve roots were sacrificed in four cases, three nerve roots in eight cases, and two nerve roots in 22 cases. Nerve roots were sacrificed bilaterally in 12 cases. Most patients (47/49) had no changes in MEP/SSEP and had no neurological deficit postoperatively. One case of a spinal sarcoma demonstrated changes in MEP after temporary clipping of the left T11 nerve root. The nerve was not sacrificed, and the patient was neurologically intact after surgery. In another case of a sarcoma, MEPs changed in the lower limbs after ligation of left T9 nerve root. It was felt that it was a global event because of anesthesia. Postoperatively, the patient had complete paraplegia but recovered almost completely after 6 months. Temporary nerve root clipping combined with MEP and SSEP monitoring may enhance the impact of neuromonitoring in the intraoperative management of patients with thoracic spine tumors and favorably influence neurological outcome. Copyright 2010 Elsevier Inc. All rights reserved.

Local and systemic mycorrhiza-induced protection against the ectoparasitic nematode Xiphinema index involves priming of defence gene responses in grapevine.

PubMed

Hao, Zhipeng; Fayolle, Léon; van Tuinen, Diederik; Chatagnier, Odile; Li, Xiaolin; Gianinazzi, Silvio; Gianinazzi-Pearson, Vivienne

2012-06-01

The ectoparasitic dagger nematode (Xiphinema index), vector of Grapevine fanleaf virus (GFLV), provokes gall formation and can cause severe damage to the root system of grapevines. Mycorrhiza formation by Glomus (syn. Rhizophagus) intraradices BEG141 reduced both gall formation on roots of the grapevine rootstock SO4 (Vitis berlandieri×V. riparia) and nematode number in the surrounding soil. Suppressive effects increased with time and were greater when the nematode was post-inoculated rather than co-inoculated with the arbuscular mycorrhizal (AM) fungus. Using a split-root system, decreased X. index development was shown in mycorrhizal and non-mycorrhizal parts of mycorrhizal root systems, indicating that both local and systemic induced bioprotection mechanisms were active against the ectoparasitic nematode. Expression analyses of ESTs (expressed sequence tags) generated in an SSH (subtractive suppressive hybridization) library, representing plant genes up-regulated during mycorrhiza-induced control of X. index, and of described grapevine defence genes showed activation of chitinase 1b, pathogenesis-related 10, glutathione S-transferase, stilbene synthase 1, 5-enolpyruvyl shikimate-3-phosphate synthase, and a heat shock proein 70-interacting protein in association with the observed local and/or systemic induced bioprotection against the nematode. Overall, the data suggest priming of grapevine defence responses by the AM fungus and transmission of a plant-mediated signal to non-mycorrhizal tissues. Grapevine gene responses during AM-induced local and systemic bioprotection against X. index point to biological processes that are related either to direct effects on the nematode or to protection against nematode-imposed stress to maintain root tissue integrity.

THttpServer class in ROOT

NASA Astrophysics Data System (ADS)

Adamczewski-Musch, Joern; Linev, Sergey

2015-12-01

The new THttpServer class in ROOT implements HTTP server for arbitrary ROOT applications. It is based on Civetweb embeddable HTTP server and provides direct access to all objects registered for the server. Objects data could be provided in different formats: binary, XML, GIF/PNG, and JSON. A generic user interface for THttpServer has been implemented with HTML/JavaScript based on JavaScript ROOT development. With any modern web browser one could list, display, and monitor objects available on the server. THttpServer is used in Go4 framework to provide HTTP interface to the online analysis.

Lateral root initiation in Marsilea quadrifolia. I. Origin and histogensis of lateral roots

NASA Technical Reports Server (NTRS)

Lin, B. L.; Raghavan, V.

1991-01-01

In Marsilea quadrifolia, lateral roots arise from modified single cells of the endodermis located opposite the protoxylem poles within the meristematic region of the parent root. The initial cell divides in four specific planes to establish a five-celled lateral root primordium, with a tetrahedral apical cell in the centre and the oldest merophytes and the root cap along the sides. The cells of the merophyte divide in a precise pattern to give rise to the cells of the cortex, endodermis, pericycle, and vascular tissues of the emerging lateral root. Although the construction of the parent root is more complicated than that of lateral roots, patterns of cell division and tissue formation are similar in both types of roots, with the various tissues being arranged in similar positions in relation to the central axis. Vascular connection between the lateral root primordium and the parent root is derived from the pericycle cells lying between the former and the protoxylem members of the latter. It is proposed that the central axis of the root is not only a geometric centre, but also a physiological centre which determines the fate of the different cell types.

Strigolactones Effects on Root Growth

NASA Astrophysics Data System (ADS)

Koltai, Hinanit

2012-07-01

Strigolactones (SLs) were defined as a new group of plant hormones that suppress lateral shoot branching. Our previous studies suggested SLs to be regulators of root development. SLs were shown to alter root architecture by regulating lateral root formation and to affect root hair elongation in Arabidopsis. Another important effect of SLs on root growth was shown to be associated with root directional growth. Supplementation of SLs to roots led to alterations in root directional growth, whereas associated mutants showed asymmetrical root growth, which was influenced by environmental factors. The regulation by SLs of root development was shown to be conducted via a cross talk of SLs with other plant hormones, including auxin. SLs were shown to regulate auxin transport, and to interfere with the activity of auxin-efflux carriers. Therefore, it might be that SLs are regulators of root directional growth as a result of their ability to regulated auxin transport. However, other evidences suggest a localized effect of SLs on cell division, which may not necessarily be associated with auxin efflux. These and other, recent hypothesis as to the SLs mode of action and the associated root perception and response to environmental factors will be discussed.

Circular zig-zag scan video format

DOEpatents

Peterson, C. Glen; Simmons, Charles M.

1992-01-01

A circular, ziz-zag scan for use with vidicon tubes. A sine wave is generated, rectified and its fourth root extracted. The fourth root, and its inverse, are used to generate horizontal ramp and sync signals. The fourth root is also used to generate a vertical sync signal, and the vertical sync signal, along with the horizontal sync signal, are used to generate the vertical ramp signal. Cathode blanking and preamplifier clamp signals are also obtained from the vertical sync signal.

A higher sink competitiveness of the rooting zone and invertases are involved in dark stimulation of adventitious root formation in Petunia hybrida cuttings.

PubMed

Klopotek, Yvonne; Franken, Philipp; Klaering, Hans-Peter; Fischer, Kerstin; Hause, Bettina; Hajirezaei, Mohammad-Reza; Druege, Uwe

2016-02-01

The contribution of carbon assimilation and allocation and of invertases to the stimulation of adventitious root formation in response to a dark pre-exposure of petunia cuttings was investigated, considering the rooting zone (stem base) and the shoot apex as competing sinks. Dark exposure had no effect on photosynthesis and dark respiration during the subsequent light period, but promoted dry matter partitioning to the roots. Under darkness, higher activities of cytosolic and vacuolar invertases were maintained in both tissues when compared to cuttings under light. This was partially associated with higher RNA levels of respective genes. However, activity of cell wall invertases and transcript levels of one cell wall invertase isogene increased specifically in the stem base during the first two days after cutting excision under both light and darkness. During five days after excision, RNA accumulation of four invertase genes indicated preferential expression in the stem base compared to the apex. Darkness shifted the balance of expression of one cytosolic and two vacuolar invertase genes towards the stem base. The results indicate that dark exposure before planting enhances the carbon sink competitiveness of the rooting zone and that expression and activity of invertases contribute to the shift in carbon allocation. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

An Autophagy-Related Kinase Is Essential for the Symbiotic Relationship between Phaseolus vulgaris and Both Rhizobia and Arbuscular Mycorrhizal Fungi[OPEN

PubMed Central

Estrada-Navarrete, Georgina; Cruz-Mireles, Neftaly; Barraza, Aarón; Olivares, Juan E.; Quinto, Carmen

2016-01-01

Eukaryotes contain three types of lipid kinases that belong to the phosphatidylinositol 3-kinase (PI3K) family. In plants and Saccharomyces cerevisiae, only PI3K class III family members have been identified. These enzymes regulate the innate immune response, intracellular trafficking, autophagy, and senescence. Here, we report that RNAi-mediated downregulation of common bean (Phaseolus vulgaris) PI3K severely impaired symbiosis in composite P. vulgaris plants with endosymbionts such as Rhizobium tropici and Rhizophagus irregularis. Downregulation of Pv-PI3K was associated with a marked decrease in root hair growth and curling. Additionally, infection thread growth, root-nodule number, and symbiosome formation in root nodule cells were severely affected. Interestingly, root colonization by AM fungi and the formation of arbuscules were also abolished in PI3K loss-of-function plants. Furthermore, the transcript accumulation of genes encoding proteins known to interact with PI3K to form protein complexes involved in autophagy was drastically reduced in these transgenic roots. RNAi-mediated downregulation of one of these genes, Beclin1/Atg6, resulted in a similar phenotype as observed for transgenic roots in which Pv-PI3K had been downregulated. Our findings show that an autophagy-related process is crucial for the mutualistic interactions of P. vulgaris with beneficial microorganisms. PMID:27577790

PHOTOPERIOD RESPONSE 1 (PHOR1)-like genes regulate shoot/root growth, starch accumulation, and wood formation in Populus.

PubMed

Zawaski, Christine; Ma, Cathleen; Strauss, Steven H; French, Darla; Meilan, Richard; Busov, Victor B

2012-09-01

This study describes functional characterization of two putative poplar PHOTOPERIOD RESPONSE 1 (PHOR1) orthologues. The expression and sequence analyses indicate that the two poplar genes diverged, at least partially, in function. PtPHOR1_1 is most highly expressed in roots and induced by short days, while PtPHOR1_2 is more uniformly expressed throughout plant tissues and is not responsive to short days. The two PHOR1 genes also had distinct effects on shoot and root growth when their expression was up- and downregulated transgenically. PtPHOR1_1 effects were restricted to roots while PtPHOR1_2 had similar effects on aerial and below-ground development. Nevertheless, both genes seemed to be upregulated in transgenic poplars that are gibberellin-deficient and gibberellin-insensitive, suggesting interplay with gibberellin signalling. PHOR1 suppression led to increased starch accumulation in both roots and stems. The effect of PHOR1 suppression on starch accumulation was coupled with growth-inhibiting effects in both roots and shoots, suggesting that PHOR1 is part of a mechanism that regulates the allocation of carbohydrate to growth or storage in poplar. PHOR1 downregulation led to significant reduction of xylem formation caused by smaller fibres and vessels suggesting that PHOR1 likely plays a role in the growth of xylem cells.

PHOTOPERIOD RESPONSE 1 (PHOR1)-like Genes Regulate Shoot/root Growth, Starch Accumulation, and Wood Formation in Populus

PubMed Central

Busov, Victor B.

2012-01-01

This study describes functional characterization of two putative poplar PHOTOPERIOD RESPONSE 1 (PHOR1) orthologues. The expression and sequence analyses indicate that the two poplar genes diverged, at least partially, in function. PtPHOR1_1 is most highly expressed in roots and induced by short days, while PtPHOR1_2 is more uniformly expressed throughout plant tissues and is not responsive to short days. The two PHOR1 genes also had distinct effects on shoot and root growth when their expression was up- and downregulated transgenically. PtPHOR1_1 effects were restricted to roots while PtPHOR1_2 had similar effects on aerial and below-ground development. Nevertheless, both genes seemed to be upregulated in transgenic poplars that are gibberellin-deficient and gibberellin-insensitive, suggesting interplay with gibberellin signalling. PHOR1 suppression led to increased starch accumulation in both roots and stems. The effect of PHOR1 suppression on starch accumulation was coupled with growth-inhibiting effects in both roots and shoots, suggesting that PHOR1 is part of a mechanism that regulates the allocation of carbohydrate to growth or storage in poplar. PHOR1 downregulation led to significant reduction of xylem formation caused by smaller fibres and vessels suggesting that PHOR1 likely plays a role in the growth of xylem cells. PMID:22915748

Expression of animal anti-apoptotic gene Ced-9 enhances tolerance during Glycine max L.-Bradyrhizobium japonicum interaction under saline stress but reduces nodule formation.

PubMed

Robert, Germán; Muñoz, Nacira; Melchiorre, Mariana; Sánchez, Federico; Lascano, Ramiro

2014-01-01

The mechanisms by which the expression of animal cell death suppressors in economically important plants conferred enhanced stress tolerance are not fully understood. In the present work, the effect of expression of animal antiapoptotic gene Ced-9 in soybean hairy roots was evaluated under root hairs and hairy roots death-inducing stress conditions given by i) Bradyrhizobium japonicum inoculation in presence of 50 mM NaCl, and ii) severe salt stress (150 mM NaCl), for 30 min and 3 h, respectively. We have determined that root hairs death induced by inoculation in presence of 50 mM NaCl showed characteristics of ordered process, with increased ROS generation, MDA and ATP levels, whereas the cell death induced by 150 mM NaCl treatment showed non-ordered or necrotic-like characteristics. The expression of Ced-9 inhibited or at least delayed root hairs death under these treatments. Hairy roots expressing Ced-9 had better homeostasis maintenance, preventing potassium release; increasing the ATP levels and controlling the oxidative damage avoiding the increase of reactive oxygen species production. Even when our results demonstrate a positive effect of animal cell death suppressors in plant cell ionic and redox homeostasis under cell death-inducing conditions, its expression, contrary to expectations, drastically inhibited nodule formation even under control conditions.

Horizontal root fracture treated with MTA, a case report with a 10-year follow-up.

PubMed

Roig, Miguel; Espona, José; Mercadé, Montse; Duran-Sindreu, Fernando

2011-12-01

Root fractures occur more frequently in fully erupted permanent teeth with closed apices in which the completely formed root is solidly supported in the bone and periodontium. The consequences can be complex because of combined damage to the pulp, dentine, cementum, bone, and periodontium. Management of horizontal root fractures and lateral luxation depends on several factors, with the result that various clinical modalities have been suggested. This case report describes the treatment and 10-year follow-up of two maxillary central incisors, one with horizontal root fracture and the other with lateral luxation, treated with mineral trioxide aggregate and root canal treatment, respectively. © 2011 John Wiley & Sons A/S.

Plant growth, biomass partitioning and soil carbon formation in response to altered lignin biosynthesis in Populus tremuloides.

PubMed

Hancock, Jessica E; Loya, Wendy M; Giardina, Christian P; Li, Laigeng; Chiang, Vincent L; Pregitzer, Kurt S

2007-01-01

We conducted a glasshouse mesocosm study that combined (13)C isotope techniques with wild-type and transgenic aspen (Populus tremuloides) in order to examine how altered lignin biosynthesis affects plant production and soil carbon formation. Our transgenic aspen lines expressed low stem lignin concentration but normal cellulose concentration, low lignin stem concentration with high cellulose concentration or an increased stem syringyl to guaiacyl lignin ratio. Large differences in stem lignin concentration observed across lines were not observed in leaves or fine roots. Nonetheless, low lignin lines accumulated 15-17% less root C and 33-43% less new soil C than the control line. Compared with the control line, transformed aspen expressing high syringyl lignin accumulated 30% less total plant C - a result of greatly reduced total leaf area - and 70% less new soil C. These findings suggest that altered stem lignin biosynthesis in Populus may have little effect on the chemistry of fine roots or leaves, but can still have large effects on plant growth, biomass partitioning and soil C formation.

Characterisation of Roseomonas mucosa isolated from the root canal of an infected tooth.

PubMed

Diesendorf, Nina; Köhler, Stefanie; Geißdörfer, Walter; Grobecker-Karl, Tanja; Karl, Matthias; Burkovski, Andreas

2017-06-14

The genus Roseomonas comprises a group of pink-pigmented, slow-growing, aerobic, non-fermentative Gram-negative bacteria, which have been isolated from environmental sources such as water and soil, but are also associated with human infections. In the study presented here, Roseomonas mucosa was identified for the first time as part of the endodontic microbiota of an infected root canal and characterised in respect to growth, antibiotic susceptibility and biofilm formation. The isolated R. mucosa strain showed strong slime formation and was resistant to most β-lactam antibiotics, while it was susceptible to aminoglycosides, carbapenemes, fluorochinolones, polymyxines, sulfonamides and tetracyclines. Biofilm formation on artificial surfaces (glass, polystyrene, gutta-percha) and on teeth was tested using colorimetric and fluorescence microscopic assays. While solid biofilms were formed on glass surfaces, on the hydrophobic surface of gutta-percha points, no confluent but localised, spotty biofilms were observed. Furthermore, R. mucosa was able form biofilms on dentin. The data obtained indicate that R. mucosa can support establishment of endodontic biofilms and furthermore, infected root canals might serve as an entrance pathway for blood stream infections by this emerging pathogen.

An in-vitro comparison of the radiographic and actual gutta-percha terminus.

PubMed

Namazikhah, M S; Ghiai, M; Parkin, M J; Puccinelli, L

2000-06-01

The purpose of this study was to investigate the difference between the radiographic gutta-percha terminus and the actual gutta-percha terminus of human molars by comparing radiographic obturation results with actual obturation results. Forty maxillary palatal roots and 50 mandibular distal roots were randomly selected from a population of 540. They were then mounted in stone and radiographed. Conventional endodontic therapy was completed using stainless-steel K files and lateral condensation. Each radiographic gutta-percha terminus was evaluated under 4.5x magnification by three examiners following the completion of root canal therapy. These results were recorded. Each tooth was then removed from its mounting, and the actual gutta-percha terminus was evaluated under 4.5x magnification. These results were recorded and compared to the radiographic gutta-percha terminus results. In all 90 teeth examined, the actual gutta-percha terminus was equal to or longer than the radiographic gutta-percha terminus. In the 50 mandibular distal roots, the actual gutta-percha terminus averaged 0.645 mm longer than the radiographic gutta-percha terminus. In the 40 maxillary palatal roots, this difference measured 0.6375 mm.

Effect of Instrumentation Length and Instrumentation Systems: Hand Versus Rotary Files on Apical Crack Formation – An In vitro Study

PubMed Central

Mahesh, MC; Bhandary, Shreetha

2017-01-01

Introduction Stresses generated during root canal instrumentation have been reported to cause apical cracks. The smaller, less pronounced defects like cracks can later propagate into vertical root fracture, when the tooth is subjected to repeated stresses from endodontic or restorative procedures. Aim This study evaluated occurrence of apical cracks with stainless steel hand files, rotary NiTi RaCe and K3 files at two different instrumentation lengths. Materials and Methods In the present in vitro study, 60 mandibular premolars were mounted in resin blocks with simulated periodontal ligament. Apical 3 mm of the root surfaces were exposed and stained using India ink. Preoperative images of root apices were obtained at 100x using stereomicroscope. The teeth were divided into six groups of 10 each. First two groups were instrumented with stainless steel files, next two groups with rotary NiTi RaCe files and the last two groups with rotary NiTi K3 files. The instrumentation was carried out till the apical foramen (Working Length-WL) and 1 mm short of the apical foramen (WL-1) with each file system. After root canal instrumentation, postoperative images of root apices were obtained. Preoperative and postoperative images were compared and the occurrence of cracks was recorded. Descriptive statistical analysis and Chi-square tests were used to analyze the results. Results Apical root cracks were seen in 30%, 35% and 20% of teeth instrumented with K-files, RaCe files and K3 files respectively. There was no statistical significance among three instrumentation systems in the formation of apical cracks (p=0.563). Apical cracks were seen in 40% and 20% of teeth instrumented with K-files; 60% and 10% of teeth with RaCe files and 40% and 0% of teeth with K3 files at WL and WL-1 respectively. For groups instrumented with hand files there was no statistical significance in number of cracks at WL and WL-1 (p=0.628). But for teeth instrumented with RaCe files and K3 files significantly more number of cracks were seen at WL than WL-1 (p=0.057 for RaCe files and p=0.087 for K3 files). Conclusion There was no statistical significance between stainless steel hand files and rotary files in terms of crack formation. Instrumentation length had a significant effect on the formation of cracks when rotary files were used. Using rotary instruments 1 mm short of apical foramen caused lesser crack formation. But, there was no statistically significant difference in number of cracks formed with hand files at two instrumentation levels. PMID:28274036

Effect of Instrumentation Length and Instrumentation Systems: Hand Versus Rotary Files on Apical Crack Formation - An In vitro Study.

PubMed

Devale, Madhuri R; Mahesh, M C; Bhandary, Shreetha

2017-01-01

Stresses generated during root canal instrumentation have been reported to cause apical cracks. The smaller, less pronounced defects like cracks can later propagate into vertical root fracture, when the tooth is subjected to repeated stresses from endodontic or restorative procedures. This study evaluated occurrence of apical cracks with stainless steel hand files, rotary NiTi RaCe and K3 files at two different instrumentation lengths. In the present in vitro study, 60 mandibular premolars were mounted in resin blocks with simulated periodontal ligament. Apical 3 mm of the root surfaces were exposed and stained using India ink. Preoperative images of root apices were obtained at 100x using stereomicroscope. The teeth were divided into six groups of 10 each. First two groups were instrumented with stainless steel files, next two groups with rotary NiTi RaCe files and the last two groups with rotary NiTi K3 files. The instrumentation was carried out till the apical foramen (Working Length-WL) and 1 mm short of the apical foramen (WL-1) with each file system. After root canal instrumentation, postoperative images of root apices were obtained. Preoperative and postoperative images were compared and the occurrence of cracks was recorded. Descriptive statistical analysis and Chi-square tests were used to analyze the results. Apical root cracks were seen in 30%, 35% and 20% of teeth instrumented with K-files, RaCe files and K3 files respectively. There was no statistical significance among three instrumentation systems in the formation of apical cracks (p=0.563). Apical cracks were seen in 40% and 20% of teeth instrumented with K-files; 60% and 10% of teeth with RaCe files and 40% and 0% of teeth with K3 files at WL and WL-1 respectively. For groups instrumented with hand files there was no statistical significance in number of cracks at WL and WL-1 (p=0.628). But for teeth instrumented with RaCe files and K3 files significantly more number of cracks were seen at WL than WL-1 (p=0.057 for RaCe files and p=0.087 for K3 files). There was no statistical significance between stainless steel hand files and rotary files in terms of crack formation. Instrumentation length had a significant effect on the formation of cracks when rotary files were used. Using rotary instruments 1 mm short of apical foramen caused lesser crack formation. But, there was no statistically significant difference in number of cracks formed with hand files at two instrumentation levels.

Root Type-Specific Reprogramming of Maize Pericycle Transcriptomes by Local High Nitrate Results in Disparate Lateral Root Branching Patterns1[OPEN

PubMed Central

Lithio, Andrew

2016-01-01

The adaptability of root system architecture to unevenly distributed mineral nutrients in soil is a key determinant of plant performance. The molecular mechanisms underlying nitrate dependent plasticity of lateral root branching across the different root types of maize are only poorly understood. In this study, detailed morphological and anatomical analyses together with cell type-specific transcriptome profiling experiments combining laser capture microdissection with RNA-seq were performed to unravel the molecular signatures of lateral root formation in primary, seminal, crown, and brace roots of maize (Zea mays) upon local high nitrate stimulation. The four maize root types displayed divergent branching patterns of lateral roots upon local high nitrate stimulation. In particular, brace roots displayed an exceptional architectural plasticity compared to other root types. Transcriptome profiling revealed root type-specific transcriptomic reprogramming of pericycle cells upon local high nitrate stimulation. The alteration of the transcriptomic landscape of brace root pericycle cells in response to local high nitrate stimulation was most significant. Root type-specific transcriptome diversity in response to local high nitrate highlighted differences in the functional adaptability and systemic shoot nitrogen starvation response during development. Integration of morphological, anatomical, and transcriptomic data resulted in a framework underscoring similarity and diversity among root types grown in heterogeneous nitrate environments. PMID:26811190

Cytokinin-induced promotion of root meristem size in the fern Azolla supports a shoot-like origin of euphyllophyte roots.

PubMed

de Vries, Jan; Fischer, Angela Melanie; Roettger, Mayo; Rommel, Sophie; Schluepmann, Henriette; Bräutigam, Andrea; Carlsbecker, Annelie; Gould, Sven Bernhard

2016-01-01

The phytohormones cytokinin and auxin orchestrate the root meristem development in angiosperms by determining embryonic bipolarity. Ferns, having the most basal euphyllophyte root, form neither bipolar embryos nor permanent embryonic primary roots but rather an adventitious root system. This raises the questions of how auxin and cytokinin govern fern root system architecture and whether this can tell us something about the origin of that root. Using Azolla filiculoides, we characterized the influence of IAA and zeatin on adventitious fern root meristems and vasculature by Nomarski microscopy. Simultaneously, RNAseq analyses, yielding 36,091 contigs, were used to uncover how the phytohormones affect root tip gene expression. We show that auxin restricts Azolla root meristem development, while cytokinin promotes it; it is the opposite effect of what is observed in Arabidopsis. Global gene expression profiling uncovered 145 genes significantly regulated by cytokinin or auxin, including cell wall modulators, cell division regulators and lateral root formation coordinators. Our data illuminate both evolution and development of fern roots. Promotion of meristem size through cytokinin supports the idea that root meristems of euphyllophytes evolved from shoot meristems. The foundation of these roots was laid in a postembryonically branching shoot system. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Sterilization of root canal spaces using an Nd:YAG laser, in vitro

NASA Astrophysics Data System (ADS)

Goodis, Harold E.; White, Joel M.; Yee, Barbara; Marshall, Sally J.; Marshall, Grayson W.

1995-05-01

A smear layer is created during the cleaning and shaping of root canal systems. The Nd:YAG laser has been shown to be effective in removing that smear layer and any tissue remnants from prepared root canal systems suggesting that it may aid in root canal sterilization without detrimental thermal effects to adjacent tissues. The root canal system of 72 single-rooted teeth was conventionally prepared and sterilized using gamma radiation. The teeth were divided into three groups of 24 each, 8 of which were inoculated only with sterile broth and remained as negative controls. Sixteen teeth of each group were inoculated with one of three organisms of 106 to 1010 CFU/(mu) l: B subtilis (BS), E. coli (EC) and S. marcescens (SM) (10 (mu) l). Eight in each group were not treated further and served as positive controls. Sixteen test teeth were treated with the laser three times using each exposure parameter: 1 W, 10 Hz pulses per second (pps); 2 W, 20 Hz; and 3 W, 30 Hz inserted to the radiographic apex. Laser exposures were completed while withdrawing the fiber from the root canal system. At completion of laser exposure, all teeth were cultured, using sterile paper points and plated on brain heat infusion agar. Three cultures were taken for each tooth, the plates incubated for 72 hours, and read for the presence of growth of colony-forming units. The laser was able to reduce the number of organisms placed in root canal systems, and suggests that the laser may be used in root canal therapy for bacterial reduction and cleaning of the root canal space.

Evaluation of Dentin Defect Formation during Retreatment with Hand and Rotary Instruments: A Micro-CT Study.

PubMed

Yilmaz, Ayca; Helvacioglu-Yigit, Dilek; Gur, Cansu; Ersev, Handan; Kiziltas Sendur, Gullu; Avcu, Egemen; Baydemir, Canan; Abbott, Paul Vincent

2017-01-01

The purpose of this study was to compare the incidence and longitudinal propagation of dentin defects after gutta-percha removal with hand and rotary instruments using microcomputed tomography. Twenty mandibular incisors were prepared using the balanced-force technique and scanned in a 19.9  μ m resolution. Following filling with the lateral compaction technique, gutta-percha was removed with ProTaper Universal Retreatment (PTUR) or hand instruments. After rescanning, a total of 24,120 cross-sectional images were analyzed. The numbers, types, and longitudinal length changes of defects were recorded. Defects were observed in 36.90% of the cross sections. A total of 73 defects were comprised of 87.67% craze lines, 2.73% partial cracks, and 9.58% fractures. No significant difference in terms of new defect formation was detected between the retreatment groups. The apical and middle portions of the roots had more dentin defects than the coronal portions. Defects in three roots of the PTUR instrument group increased in length. Under the conditions of this in vitro study, gutta-percha removal seemed to not increase the incidence of dentin defect formation, but the longitudinal defect propagation finding suggests possible cumulative dentinal damage due to additional endodontic procedures. Hand and rotary instrumentation techniques caused similar dentin defect formation during root canal retreatment.

Red mud (RM)-Induced enhancement of iron plaque formation reduces arsenic and metal accumulation in two wetland plant species.

PubMed

Yang, J X; Guo, Q J; Yang, J; Zhou, X Y; Ren, H Y; Zhang, H Z; Xu, R X; Wang, X D; Peters, M; Zhu, G X; Wei, R F; Tian, L Y; Han, X K

2016-01-01

Human activities have resulted in arsenic (As) and heavy metals accumulation in paddy soils in China. Phytoremediation has been suggested as an effective and low-cost method to clean up contaminated soils. A combined soil-sand pot experiment was conducted to investigate the influence of red mud (RM) supply on iron plaque formation and As and heavy metal accumulation in two wetland plant species (Cyperus alternifolius Rottb., Echinodorus amazonicus Rataj), using As and heavy metals polluted paddy soil combined with three rates of RM application (0, 2%, 5%). The results showed that RM supply significantly decreased As and heavy metals accumulation in shoots of the two plants due to the decrease of As and heavy metal availability and the enhancement of the formation of iron plaque on the root surface and in the rhizosphere. Both wetland plants supplied with RM tended to have more Fe plaque, higher As and heavy metals on roots and in their rhizospheres, and were more tolerant of As and heavy metal toxicity. The results suggest that RM-induced enhancement of the formation of iron plaque on the root surface and in the rhizosphere of wetland plants may be significant for remediation of soils contaminated with As and heavy metals.

Altered tibiofemoral contact mechanics due to lateral meniscus posterior horn root avulsions and radial tears can be restored with in situ pull-out suture repairs.

PubMed

LaPrade, Christopher M; Jansson, Kyle S; Dornan, Grant; Smith, Sean D; Wijdicks, Coen A; LaPrade, Robert F

2014-03-19

An avulsion of the posterior root attachment of the lateral meniscus or a radial tear close to the root attachment can lead to degenerative knee arthritis. Although the biomechanical effects of comparable injuries involving the medial meniscus have been studied, we are aware of no such study involving the lateral meniscus. We hypothesized that in situ pull-out suture repair of lateral meniscus root avulsions and of complete radial tears 3 and 6 mm from the root attachment would increase the contact area and decrease mean and peak tibiofemoral contact pressures, at all knee flexion angles, relative to the corresponding avulsion or tear condition. Eight human cadaveric knees underwent biomechanical testing. Eight lateral meniscus conditions (intact, footprint tear, root avulsion, root avulsion repair, radial tears at 3 and 6 mm from the posterior root, and repairs of the 3 and 6-mm tears) were tested at five different flexion angles (0°, 30°, 45°, 60°, and 90°) under a compressive 1000-N load. Avulsion of the posterior root of the lateral meniscus or an adjacent radial tear resulted in significantly decreased contact area and increased mean and peak contact pressures in the lateral compartment, relative to the intact condition, in all cases except the root avulsion condition at 0° of flexion. In situ pull-out suture repair of the root avulsion or radial tear significantly reduced mean contact pressures, relative to the corresponding avulsion or tear condition, when the results for each condition were pooled across all flexion angles. Posterior horn root avulsions and radial tears adjacent to the root attachment of the lateral meniscus significantly increased contact pressures in the lateral compartment. In situ pull-out suture repairs of these tears significantly improved lateral compartment joint contact pressures. In situ repair may be an effective treatment to improve tibiofemoral contact profiles after an avulsion of the posterior root of the lateral meniscus or a complete radial tear adjacent to the root. In situ repairs should be further investigated clinically as an alternative to partial lateral meniscectomy.

Endodontic Management of a Maxillary Lateral Incisor with 4 Root Canals and a Dens Invaginatus Tract.

PubMed

Nosrat, Ali; Schneider, S Craig

2015-07-01

Dens invaginatus (DI) is associated with complex internal anatomy. This article represents a maxillary lateral incisor with 5 root canals including DI. The treatment was planned and performed using cone-beam computed tomographic (CBCT) imaging. After clinical and radiographic evaluations, tooth #7 was diagnosed with DI and pulp necrosis with symptomatic apical periodontitis. Periapical radiographs of the tooth showed 2 roots and complex internal anatomy. CBCT evaluation revealed tooth #7 had 5 separate canals (4 root canals and 1 DI canal extending through the root to the periodontal ligament), communication between DI and the root canal system, and severe and multiple curvatures of the palatal canals. Root canal treatment was completed in 2 visits. Modified access openings were required to safely treat the dilacerated palatal canals. At the 6-month re-evaluation, the patient reported he had remained asymptomatic and his tooth had remained functional since the treatment was completed. Clinical examination showed tooth #7 had no sensitivity to percussion or palpation, probe depths within normal limits (≤3 mm), and no mobility. Radiographic assessment of the tooth showed significant osseous healing of the preoperative lesion. Three-dimensional imaging is a valuable tool for endodontic management of teeth with complex internal anatomy. Three-dimensional imaging is recommended for evaluating and treatment planning cases with DI. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Indole-3-butyric acid mediates antioxidative defense systems to promote adventitious rooting in mung bean seedlings under cadmium and drought stresses.

PubMed

Li, Shi-Weng; Zeng, Xiao-Ying; Leng, Yan; Feng, Lin; Kang, Xiao-Hu

2018-06-08

In vitro experiments were performed to determine whether auxin can mediate the formation of adventitious roots in response to heavy metal and drought stresses using a model rooting plant, mung bean [Vigna radiata (L.) Wilczek]. The treatments with CdCl 2 or mannitol alone significantly inhibited the formation and growth of adventitious roots in mung bean seedlings. In contrast, when CdCl 2 or mannitol was applied together with indole-3-butyric acid (IBA), IBA considerably cancelled the inhibition of adventitious rooting by stresses. Treatment with CdCl 2 or mannitol alone significantly increased the soluble protein and malondialdehyde (MDA) contents. CdCl 2 and mannitol stress each induced differentially significant changes in the activities of antioxidative enzyme and antioxidant levels during adventitious rooting. Notably, both CdCl 2 and mannitol stress strongly reduced the peroxidase (POD) and ascorbate peroxidase (APX) activities and glutathione (GSH) and phenols levels. Catalase and superoxide dismutase (SOD) activity were enhanced by CdCl 2 but reduced by mannitol. CdCl 2 increased the ascorbate acid (ASA) level, which was decreased by mannitol. Furthermore, when CdCl 2 or mannitol was applied together with IBA, IBA counteracted the CdCl 2 - or mannitol-induced increase or decrease in certain antioxidants, MDA, and antioxidative enzymes. These results suggest that Cd and mannitol stress inhibition of adventitious rooting is associated with the regulation of antioxidative enzymes and antioxidants in cells to defense the oxidative stress. Moreover, IBA alleviates the effects of Cd and mannitol stress on the rooting process partially through the regulation of antioxidative defense systems. Copyright © 2018 Elsevier Inc. All rights reserved.

An ordered EST catalogue and gene expression profiles of cassava (Manihot esculenta) at key growth stages.

PubMed

Li, You-Zhi; Pan, Ying-Hua; Sun, Chang-Bin; Dong, Hai-Tao; Luo, Xing-Lu; Wang, Zhi-Qiang; Tang, Ji-Liang; Chen, Baoshan

2010-12-01

A cDNA library was constructed from the root tissues of cassava variety Huanan 124 at the root bulking stage. A total of 9,600 cDNA clones from the library were sequenced with single-pass from the 5'-terminus to establish a catalogue of expressed sequence tags (ESTs). Assembly of the resulting EST sequences resulted in 2,878 putative unigenes. Blastn analysis showed that 62.6% of the unigenes matched with known cassava ESTs and the rest had no 'hits' against the cassava database in the integrative PlantGDB database. Blastx analysis showed that 1,715 (59.59%) of the unigenes matched with one or more GenBank protein entries and 1,163 (40.41%) had no 'hits'. A cDNA microarray with 2,878 unigenes was developed and used to analyze gene expression profiling of Huanan 124 at key growth stages including seedling, formation of root system, root bulking, and starch maturity. Array data analysis revealed that (1) the higher ratio of up-regulated ribosome-related genes was accompanied by a high ratio of up-regulated ubiquitin, proteasome-related and protease genes in cassava roots; (2) starch formation and degradation simultaneously occur at the early stages of root development but starch degradation is declined partially due to decrease in UDP-glucose dehydrogenase activity with root maturity; (3) starch may also be synthesized in situ in roots; (4) starch synthesis, translocation, and accumulation are also associated probably with signaling pathways that parallel Wnt, LAM, TCS and ErbB signaling pathways in animals; (5) constitutive expression of stress-responsive genes may be due to the adaptation of cassava to harsh environments during long-term evolution.

The RCN1-encoded A subunit of protein phosphatase 2A increases phosphatase activity in vivo

NASA Technical Reports Server (NTRS)

Deruere, J.; Jackson, K.; Garbers, C.; Soll, D.; Delong, A.; Evans, M. L. (Principal Investigator)

1999-01-01

Protein phosphatase 2A (PP2A), a heterotrimeric serine/threonine-specific protein phosphatase, comprises a catalytic C subunit and two distinct regulatory subunits, A and B. The RCN1 gene encodes one of three A regulatory subunits in Arabidopsis thaliana. A T-DNA insertion mutation at this locus impairs root curling, seedling organ elongation and apical hypocotyl hook formation. We have used in vivo and in vitro assays to gauge the impact of the rcn1 mutation on PP2A activity in seedlings. PP2A activity is decreased in extracts from rcn1 mutant seedlings, and this decrease is not due to a reduction in catalytic subunit expression. Roots of mutant seedlings exhibit increased sensitivity to the phosphatase inhibitors okadaic acid and cantharidin in organ elongation assays. Shoots of dark-grown, but not light-grown seedlings also show increased inhibitor sensitivity. Furthermore, cantharidin treatment of wild-type seedlings mimics the rcn1 defect in root curling, root waving and hypocotyl hook formation assays. In roots of wild-type seedlings, RCN1 mRNA is expressed at high levels in root tips, and accumulates to lower levels in the pericycle and lateral root primordia. In shoots, RCN1 is expressed in the apical hook and the basal, rapidly elongating cells in etiolated hypocotyls, and in the shoot meristem and leaf primordia of light-grown seedlings. Our results show that the wild-type RCN1-encoded A subunit functions as a positive regulator of the PP2A holoenzyme, increasing activity towards substrates involved in organ elongation and differential cell elongation responses such as root curling.

Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins.

PubMed

Mei, Yu; Jia, Wen-Jing; Chu, Yu-Jia; Xue, Hong-Wei

2012-03-01

Phosphatidylinositol monophosphate 5-kinase (PIP5K) catalyzes the synthesis of PI-4,5-bisphosphate (PtdIns(4,5)P(2)) by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring, and is involved in regulating multiple developmental processes and stress responses. We here report on the functional characterization of Arabidopsis PIP5K2, which is expressed during lateral root initiation and elongation, and whose expression is enhanced by exogenous auxin. The knockout mutant pip5k2 shows reduced lateral root formation, which could be recovered with exogenous auxin, and interestingly, delayed root gravity response that could not be recovered with exogenous auxin. Crossing with the DR5-GUS marker line and measurement of free IAA content confirmed the reduced auxin accumulation in pip5k2. In addition, analysis using the membrane-selective dye FM4-64 revealed the decelerated vesicle trafficking caused by PtdIns(4,5)P(2) reduction, which hence results in suppressed cycling of PIN proteins (PIN2 and 3), and delayed redistribution of PIN2 and auxin under gravistimulation in pip5k2 roots. On the contrary, PtdIns(4,5)P(2) significantly enhanced the vesicle trafficking and cycling of PIN proteins. These results demonstrate that PIP5K2 is involved in regulating lateral root formation and root gravity response, and reveal a critical role of PIP5K2/PtdIns(4,5)P(2) in root development through regulation of PIN proteins, providing direct evidence of crosstalk between the phosphatidylinositol signaling pathway and auxin response, and new insights into the control of polar auxin transport.

Responses of root physiological characteristics and yield of sweet potato to humic acid urea fertilizer

PubMed Central

Kou, Meng; Tang, Zhonghou; Zhang, Aijun; Li, Hongmin; Wei, Meng

2017-01-01

Humic acid (HA), not only promote the growth of crop roots, they can be combined with nitrogen (N) to increase fertilizer use efficiency and yield. However, the effects of HA urea fertilizer (HA-N) on root growth and yield of sweet potato has not been widely investigated. Xushu 28 was used as the experimental crop to investigate the effects of HA-N on root morphology, active oxygen metabolism and yield under field conditions. Results showed that nitrogen application alone was not beneficial for root growth and storage root formation during the early growth stage. HA-N significantly increased the dry weight of the root system, promoted differentiation from adventitious root to storage root, and increased the overall root activity, total root length, root diameter, root surface area, as well as root volume. HA-N thus increased the activity of superoxide dismutase (SOD), peroxidase (POD), and Catalase (CAT) as well as increasing the soluble protein content of roots and decreasing the malondialdehyde (MDA) content. HA-N significantly increased both the number of storage roots per plant increased by 14.01%, and the average fresh weight per storage root increased by 13.7%, while the yield was also obviously increased by 29.56%. In this study, HA-N increased yield through a synergistic increase of biological yield and harvest index. PMID:29253886

The Suffix "-oso" in Central American Spanish.

ERIC Educational Resources Information Center

Scavnicky, Gary Eugene A.

1982-01-01

Examines the lexical formative "-oso," which is added to nominal and verbal roots to form adjectives to denote possession of the quality contained in the primitive, in Central American Spanish. Concludes it is used with traditional Spanish denotations and has undergone various semantic shifts and is being applied to roots in a completely…

Crystalline phases involved in the hydration of calcium silicate-based cements: Semi-quantitative Rietveld X-ray diffraction analysis.

PubMed

Grazziotin-Soares, Renata; Nekoofar, Mohammad H; Davies, Thomas; Hübler, Roberto; Meraji, Naghmeh; Dummer, Paul M H

2017-08-30

Chemical comparisons of powder and hydrated forms of calcium silicate cements (CSCs) and calculation of alterations in tricalcium silicate (Ca 3 SiO 5 ) calcium hydroxide (Ca(OH) 2 ) are essential for understanding their hydration processes. This study aimed to evaluate and compare these changes in ProRoot MTA, Biodentine and CEM cement. Powder and hydrated forms of tooth coloured ProRoot MTA, Biodentine and CEM cement were subjected to X-ray diffraction (XRD) analysis with Rietveld refinement to semi-quantitatively identify and quantify the main phases involved in their hydration process. Data were reported descriptively. Reduction in Ca 3 SiO 5 and formation of Ca(OH) 2 were seen after the hydration of ProRoot MTA and Biodentine; however, in the case of CEM cement, no reduction of Ca 3 SiO 5 and no formation of Ca(OH) 2 were detected. The highest percentages of amorphous phases were seen in Biodentine samples. Ettringite was detected in the hydrated forms of ProRoot MTA and CEM cement but not in Biodentine. © 2017 Australian Society of Endodontology Inc.

Circular zig-zag scan video format

DOEpatents

Peterson, C.G.; Simmons, C.M.

1992-06-09

A circular, ziz-zag scan for use with vidicon tubes is disclosed. A sine wave is generated, rectified and its fourth root extracted. The fourth root, and its inverse, are used to generate horizontal ramp and sync signals. The fourth root is also used to generate a vertical sync signal, and the vertical sync signal, along with the horizontal sync signal, are used to generate the vertical ramp signal. Cathode blanking and preamplifier clamp signals are also obtained from the vertical sync signal. 10 figs.

Plant Hormone Homeostasis, Signaling, and Function during Adventitious Root Formation in Cuttings

PubMed Central

Druege, Uwe; Franken, Philipp; Hajirezaei, Mohammad R.

2016-01-01

Adventitious root (AR) formation in cuttings is a multiphase developmental process, resulting from wounding at the cutting site and isolation from the resource and signal network of the whole plant. Though, promotive effects of auxins are widely used for clonal plant propagation, the regulation and function of plant hormones and their intricate signaling networks during AR formation in cuttings are poorly understood. In this focused review, we discuss our recent publications on the involvement of polar auxin transport (PAT) and transcriptional regulation of auxin and ethylene action during AR formation in petunia cuttings in a broad context. Integrating new findings on cuttings of other plant species and general models on plant hormone networks, a model on the regulation and function of auxin, ethylene, and jasmonate in AR formation of cuttings is presented. PAT and cutting off from the basipetal auxin drain are considered as initial principles generating early accumulation of IAA in the rooting zone. This is expected to trigger a self-regulatory process of auxin canalization and maximization to responding target cells, there inducing the program of AR formation. Regulation of auxin homeostasis via auxin influx and efflux carriers, GH3 proteins and peroxidases, of flavonoid metabolism, and of auxin signaling via AUX/IAA proteins, TOPLESS, ARFs, and SAUR-like proteins are postulated as key processes determining the different phases of AR formation. NO and H2O2 mediate auxin signaling via the cGMP and MAPK cascades. Transcription factors of the GRAS-, AP2/ERF-, and WOX-families link auxin signaling to cell fate specification. Cyclin-mediated governing of the cell cycle, modifications of sugar metabolism and microtubule and cell wall remodeling are considered as important implementation processes of auxin function. Induced by the initial wounding and other abiotic stress factors, up-regulation of ethylene biosynthesis, and signaling via ERFs and early accumulation of jasmonic acid stimulate AR formation, while both pathways are linked to auxin. Future research on the function of candidate genes should consider their tissue-specific role and regulation by environmental factors. Furthermore, the whole cutting should be regarded as a system of physiological units with diverse functions specifically responding to the environment and determining the rooting response. PMID:27064322

Plant Hormone Homeostasis, Signaling, and Function during Adventitious Root Formation in Cuttings.

PubMed

Druege, Uwe; Franken, Philipp; Hajirezaei, Mohammad R

2016-01-01

Adventitious root (AR) formation in cuttings is a multiphase developmental process, resulting from wounding at the cutting site and isolation from the resource and signal network of the whole plant. Though, promotive effects of auxins are widely used for clonal plant propagation, the regulation and function of plant hormones and their intricate signaling networks during AR formation in cuttings are poorly understood. In this focused review, we discuss our recent publications on the involvement of polar auxin transport (PAT) and transcriptional regulation of auxin and ethylene action during AR formation in petunia cuttings in a broad context. Integrating new findings on cuttings of other plant species and general models on plant hormone networks, a model on the regulation and function of auxin, ethylene, and jasmonate in AR formation of cuttings is presented. PAT and cutting off from the basipetal auxin drain are considered as initial principles generating early accumulation of IAA in the rooting zone. This is expected to trigger a self-regulatory process of auxin canalization and maximization to responding target cells, there inducing the program of AR formation. Regulation of auxin homeostasis via auxin influx and efflux carriers, GH3 proteins and peroxidases, of flavonoid metabolism, and of auxin signaling via AUX/IAA proteins, TOPLESS, ARFs, and SAUR-like proteins are postulated as key processes determining the different phases of AR formation. NO and H2O2 mediate auxin signaling via the cGMP and MAPK cascades. Transcription factors of the GRAS-, AP2/ERF-, and WOX-families link auxin signaling to cell fate specification. Cyclin-mediated governing of the cell cycle, modifications of sugar metabolism and microtubule and cell wall remodeling are considered as important implementation processes of auxin function. Induced by the initial wounding and other abiotic stress factors, up-regulation of ethylene biosynthesis, and signaling via ERFs and early accumulation of jasmonic acid stimulate AR formation, while both pathways are linked to auxin. Future research on the function of candidate genes should consider their tissue-specific role and regulation by environmental factors. Furthermore, the whole cutting should be regarded as a system of physiological units with diverse functions specifically responding to the environment and determining the rooting response.

Rapid dental development in a Middle Paleolithic Belgian Neanderthal.

PubMed

Smith, Tanya M; Toussaint, Michel; Reid, Donald J; Olejniczak, Anthony J; Hublin, Jean-Jacques

2007-12-18

The evolution of life history (pace of growth and reproduction) was crucial to ancient hominin adaptations. The study of dental development facilitates assessment of growth and development in fossil hominins with greater precision than other skeletal analyses. During tooth formation, biological rhythms manifest in enamel and dentine, creating a permanent record of growth rate and duration. Quantification of these internal and external incremental features yields developmental benchmarks, including ages at crown completion, tooth eruption, and root completion. Molar eruption is correlated with other aspects of life history. Recent evidence for developmental differences between modern humans and Neanderthals remains ambiguous. By measuring tooth formation in the entire dentition of a juvenile Neanderthal from Scladina, Belgium, we show that most teeth formed over a shorter time than in modern humans and that dental initiation and eruption were relatively advanced. By registering manifestations of stress across the dentition, we are able to present a precise chronology of Neanderthal dental development that differs from modern humans. At 8 years of age at death, this juvenile displays a degree of development comparable with modern human children who are several years older. We suggest that age at death in juvenile Neanderthals should not be assessed by comparison with modern human standards, particularly those derived from populations of European origin. Moreover, evidence from the Scladina juvenile and other similarly aged hominins suggests that a prolonged childhood and slow life history are unique to Homo sapiens.

Early steps of adventitious rooting: morphology, hormonal profiling and carbohydrate turnover in carnation stem cuttings.

PubMed

Agulló-Antón, María Ángeles; Ferrández-Ayela, Almudena; Fernández-García, Nieves; Nicolás, Carlos; Albacete, Alfonso; Pérez-Alfocea, Francisco; Sánchez-Bravo, José; Pérez-Pérez, José Manuel; Acosta, Manuel

2014-03-01

The rooting of stem cuttings is a common vegetative propagation practice in many ornamental species. A detailed analysis of the morphological changes occurring in the basal region of cultivated carnation cuttings during the early stages of adventitious rooting was carried out and the physiological modifications induced by exogenous auxin application were studied. To this end, the endogenous concentrations of five major classes of plant hormones [auxin, cytokinin (CK), abscisic acid, salicylic acid (SA) and jasmonic acid] and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid were analyzed at the base of stem cuttings and at different stages of adventitious root formation. We found that the stimulus triggering the initiation of adventitious root formation occurred during the first hours after their excision from the donor plant, due to the breakdown of the vascular continuum that induces auxin accumulation near the wounding. Although this stimulus was independent of exogenously applied auxin, it was observed that the auxin treatment accelerated cell division in the cambium and increased the sucrolytic activities at the base of the stem, both of which contributed to the establishment of the new root primordia at the stem base. Further, several genes involved in auxin transport were upregulated in the stem base either with or without auxin application, while endogenous CK and SA concentrations were specially affected by exogenous auxin application. Taken together our results indicate significant crosstalk between auxin levels, stress hormone homeostasis and sugar availability in the base of the stem cuttings in carnation during the initial steps of adventitious rooting. © 2013 Scandinavian Plant Physiology Society.

Functions of Nitric Oxide (NO) in Roots during Development and under Adverse Stress Conditions

PubMed Central

Corpas, Francisco J.; Barroso, Juan B.

2015-01-01

The free radical molecule, nitric oxide (NO), is present in the principal organs of plants, where it plays an important role in a wide range of physiological functions. Root growth and development are highly regulated by both internal and external factors such as nutrient availability, hormones, pattern formation, cell polarity and cell cycle control. The presence of NO in roots has opened up new areas of research on the role of NO, including root architecture, nutrient acquisition, microorganism interactions and the response mechanisms to adverse environmental conditions, among others. Additionally, the exogenous application of NO throughout the roots has the potential to counteract specific damages caused by certain stresses. This review aims to provide an up-to-date perspective on NO functions in the roots of higher plants. PMID:27135326

Root elongation against a constant force: experiment with a computerized feedback-controlled device

NASA Technical Reports Server (NTRS)

Kuzeja, P. S.; Lintilhac, P. M.; Wei, C.

2001-01-01

Axial force was applied to the root tip of corn (Zea mays L. cv. Merit) seedlings using a computerized, feedback-controlled mechanical device. The system's feedback capability allowed continuous control of a constant tip load, and the attached displacement transducer provided the time course of root elongation. Loads up to 7.5 g decreased the root elongation rate by 0.13 mm h-1 g-1, but loads 7.5 to 17.5 g decreased the growth rate by only 0.04 mm h-1 g-1. Loads higher than 18 g stopped root elongation completely. Measurement of the cross-sectional areas of the root tips indicated that the 18 g load had applied about 0.98 MPa of axial pressure to the root, thereby exceeding the root's ability to respond with increased turgor pressure. Recorded time-lapse images of loaded roots showed that radial thickening (swelling) occurred behind the root cap, whose cross-sectional area increased with tip load.

Determination of stress responses induced by aluminum in maize (Zea mays).

PubMed

Vardar, Filiz; Ismailoğlu, Işil; Inan, Deniz; Unal, Meral

2011-06-01

To assess the alternative responses to aluminum toxicity, maize (Zea mays L. cv Karadeniz yıldızı) roots were exposed to different concentrations of AlCl3 (150, 300 and 450 μM). Aluminum reduced the root elongation by 39.6% in 150 μM, 44.1% in 300 μM, 50.1% in 450 μM AlCl3 after 96 h period. To correlate the root elongation with the alternative stress responses including aluminum accumulation, lipid peroxidation, mitotic abnormalities, reduction of starch content, intracellular Ca2+ accumulation, callose formation, lignin deposition and peroxidase activity, cytochemical and biochemical tests were performed. The results indicated that aluminum accumulation and lipid peroxidation were observed more densely on the root cap and the outer cortex cells. In addition to morphological deformations, cytochemical analysis displayed cellular deformations. Furthermore, mitotic abnormalities were observed such as c-mitosis, micronuclei, bi- and trinucleated cells in aluminum treated root tips. Aluminum treatment induced starch reduction, callose formation, lignin accumulation and intracellular Ca2+ increase. Moreover, the peroxidase activity increased significantly by 3, 4.4 and 7.7 times higher than in that of control after 96 h, respectively. In conclusion, aluminum is significantly stressful in maize culminating in morphological and cellular alterations.

Leaf proteomic analysis in cassava (Manihot esculenta, Crantz) during plant development, from planting of stem cutting to storage root formation.

PubMed

Mitprasat, Mashamon; Roytrakul, Sittiruk; Jiemsup, Surasak; Boonseng, Opas; Yokthongwattana, Kittisak

2011-06-01

Tuberization in cassava (Manihot esculenta Crantz) occurs simultaneously with plant development, suggesting competition of photoassimilate partitioning between the shoot and the root organs. In potato, which is the most widely studied tuber crop, there is ample evidence suggesting that metabolism and regulatory processes in leaf may have an impact on tuber formation. To search for leaf proteins putatively involved in regulating tuber generation and/or development in cassava, comparative proteomic approaches have been applied to monitor differentially expressed leaf proteins during root transition from fibrous to tuberous. Stringent cross comparison and statistical analysis between two groups with different plant ages using Student's t test with 95% significance level revealed a number of protein spots whose abundance were significantly altered (P < 0.05) during week 4 to week 8 of growth. Of these, 39 spots were successfully identified by ion trap LC-MS/MS. The proteins span various functional categories from antioxidant and defense, carbohydrate metabolism, cyanogenesis, energy metabolism, miscellaneous and unknown proteins. Results suggested possible metabolic switches in the leaf that may trigger/regulate storage root initiation and growth. This study provides a basis for further functional characterization of differentially expressed leaf proteins, which can help understand how biochemical processes in cassava leaves may be involved in storage root development.

ASSESSING ROOT DEMOGRAPHY AND CARBOHYDRATE DYNAMICS OF ZOSTERA MARINA

EPA Science Inventory

To help establish protective criteria for Zostera marina a more complete understanding of the factors affecting the status, condition, distribution and ecophysiology of Z. marina is needed. While Z. marina shoots are readily observed, assessing growth and carbon dynamics of roots...

Ammonium-induced loss of root gravitropism is related to auxin distribution and TRH1 function, and is uncoupled from the inhibition of root elongation in Arabidopsis.

PubMed

Zou, Na; Li, Baohai; Dong, Gangqiang; Kronzucker, Herbert J; Shi, Weiming

2012-06-01

Root gravitropism is affected by many environmental stresses, including salinity, drought, and nutrient deficiency. One significant environmental stress, excess ammonium (NH(4)(+)), is well documented to inhibit root elongation and lateral root formation, yet little is known about its effects on the direction of root growth. We show here that inhibition of root elongation upon elevation of external NH(4)(+) is accompanied by a loss in root gravitropism (agravitropism) in Arabidopsis. Addition of potassium (K(+)) to the treatment medium partially rescued the inhibition of root elongation by high NH(4)(+) but did not improve gravitropic root curvature. Expression analysis of the auxin-responsive reporter gene DR5::GUS revealed that NH(4)(+) treatment delayed the development of gravity-induced auxin gradients across the root cap but extended their duration once initiated. Moreover, the β-glucuronidase (GUS) signal intensity in root tip cells was significantly reduced under high NH(4)(+) treatment over time. The potassium carrier mutant trh1 displayed different patterns of root gravitropism and DR5::GUS signal intensity in root apex cells compared with the wild type in response to NH(4)(+). Together, the results demonstrate that the effects of NH(4)(+) on root gravitropism are related to delayed lateral auxin redistribution and the TRH1 pathway, and are largely independent of inhibitory effects on root elongation.

MicroRNAs, polyamines, and the activities antioxidant enzymes are associated with in vitro rooting in white pine (Pinus strobus L.).

PubMed

Fei, Yunjun; Xiao, Bo; Yang, Man; Ding, Qiong; Tang, Wei

2016-01-01

Molecular mechanism of in vitro rooting in conifer is not fully understood. After establishment of a regeneration procedure in eastern white pine (Pinus strobus L.) using mature embryos as explants to induce shoot formation on medium containing 3 μM IAA, 6 μM BA and 6 μM TDZ and induce root formation on medium containing 0.001-0.05 μM IAA, 0.001-0.05 μM IBA, 0.001-0.05 μM TDZ, we have investigated the changes of polyamine content and the activities of antioxidant enzymes during in vitro rooting in P. strobus. Our results demonstrated that putrescine (Put), spermidine (Spd), and spermine (Spm) did not increase in P. strobus during the first week of rooting on medium supplemented with 0.01 μM indole-3-acetic acid (IAA), whereas the levels of Put, Spd, and Spm increased during the 1st-3rd week of culture on medium with IAA, and then decreased on medium with IAA. No such a change in Put, Spd, and Spm was observed on medium without IAA. Measurement of antioxidant enzyme activity demonstrated that the activities of polyphenol oxidase, catalase, and peroxidase slightly increased in the first week of culture and reached to the highest peak in the 3rd-5th week of culture. Quantitative RT-PCR results indicated that miR160 was increased on the 7th day, miR162, miR397, and miR408 was increased from the 21th to 35th day, miR857 was increased on the 35th day, and miR827 was increased on the 49th day. These results demonstrated that enhanced polyamine biosynthesis, antioxidant enzyme activity, and microRNAs are correlated with the root induction and formation in P. strobus.

Influence of cervical preflaring on apical file size determination.

PubMed

Pecora, J D; Capelli, A; Guerisoli, D M Z; Spanó, J C E; Estrela, C

2005-07-01

To investigate the influence of cervical preflaring with different instruments (Gates-Glidden drills, Quantec Flare series instruments and LA Axxess burs) on the first file that binds at working length (WL) in maxillary central incisors. Forty human maxillary central incisors with complete root formation were used. After standard access cavities, a size 06 K-file was inserted into each canal until the apical foramen was reached. The WL was set 1 mm short of the apical foramen. Group 1 received the initial apical instrument without previous preflaring of the cervical and middle thirds of the root canal. Group 2 had the cervical and middle portion of the root canals enlarged with Gates-Glidden drills sizes 90, 110 and 130. Group 3 had the cervical and middle thirds of the root canals enlarged with nickel-titanium Quantec Flare series instruments. Titanium-nitrite treated, stainless steel LA Axxess burs were used for preflaring the cervical and middle portions of root canals from group 4. Each canal was sized using manual K-files, starting with size 08 files with passive movements until the WL was reached. File sizes were increased until a binding sensation was felt at the WL, and the instrument size was recorded for each tooth. The apical region was then observed under a stereoscopic magnifier, images were recorded digitally and the differences between root canal and maximum file diameters were evaluated for each sample. Significant differences were found between experimental groups regarding anatomical diameter at the WL and the first file to bind in the canal (P < 0.01, 95% confidence interval). The major discrepancy was found when no preflaring was performed (0.151 mm average). The LA Axxess burs produced the smallest differences between anatomical diameter and first file to bind (0.016 mm average). Gates-Glidden drills and Flare instruments were ranked in an intermediary position, with no statistically significant differences between them (0.093 mm average). The instrument binding technique for determining anatomical diameter at WL is not precise. Preflaring of the cervical and middle thirds of the root canal improved anatomical diameter determination; the instrument used for preflaring played a major role in determining the anatomical diameter at the WL. Canals preflared with LA Axxess burs created a more accurate relationship between file size and anatomical diameter.

Low phosphate alters lateral root setpoint angle and gravitropism.

PubMed

Bai, Hanwen; Murali, Bhavna; Barber, Kevin; Wolverton, Chris

2013-01-01

Lateral roots, responsible for water and nutrient uptake, maintain nonvertical angles throughout development. Soil phosphate is one limiting nutrient for plant growth that is known to induce changes to root system architecture, such as increased lateral root formation. This study seeks to determine whether phosphate concentration affects lateral root orientation in addition to its previously described influences on root architecture. Images of intact Arabidopsis root systems were recorded for 24 h, and lateral root tip angles were measured for wild-type and mutant pgm-1 and pin3-1 roots on a full or low phosphate medium. Setpoint angles of unstimulated root systems were determined, as were gravitropic responses of lateral roots over time. The root system setpoint angles of wild-type and mutant pin3-1 roots showed a shift toward a more vertical orientation on low orthophosphate (Pi) medium. The gravitropic responses of both pgm-1 and pin3-1 roots on low Pi medium was elevated relative to control Pi medium. Mutations in two phosphate transporters with high levels of expression in the root showed a gravitropic response similar to wild-type roots grown on low Pi, supporting a role for Pi status in regulating lateral root gravitropism. Lateral root orientation and gravitropism are affected by Pi status and may provide an important additional parameter for describing root responses to low Pi. The data also support the conclusion that gravitropic setpoint angle reacts to nutrient status and is under dynamic regulation.

Incidence of Postoperative Pain after Single Visit and Two Visit Root Canal Therapy: A Randomized Controlled Trial

PubMed Central

Joshi, Sonal B.; Bhagwat, S.V; Patil, Sanjana A

2016-01-01

Introduction Root Canal Treatment (RCT) has become a mainstream procedure in dentistry. A successful RCT is presented by absence of clinical signs and symptoms in teeth without any radiographic evidence of periodontal involvement. Completing this procedure in one visit or multiple visits has long been a topic of discussion. Aim To evaluate the incidence of postoperative pain after root canal therapy performed in single visit and two visits. Material and Methods An unblinded/ open label randomized controlled trial was carried out in the endodontic department of the Dental Institute, where 78 patients were recruited from the regular pool of patients. A total of 66 maxillary central incisors requiring root canal therapy fulfilled the inclusion and exclusion criteria. Using simple randomization by biased coin randomization method, the selected patients were assigned into two groups: group A (n=33) and group B (n=33). Single visit root canal treatment was performed for group A and two visit root canal treatment for group B. Independent sample t-test was used for statistical analysis. Results Thirty three patients were allotted to group A where endodontic treatment was completed in single visit while 33 patients were allotted to group B where endodontic treatment was completed in two visits. One patient dropped-out from Group A. Hence in Group A, 32 patients were analysed while in Group B, 33 patients were analysed. After 6 hours, 12 hours and 24 hours of obturation, pain was significantly higher in Group B as compared to Group A. However, there was no significant difference in the pain experienced by the patients 48 hours after treatment in both the groups. Conclusion Incidence of pain after endodontic treatment being performed in one-visit or two-visits is not significantly different. PMID:27437339

Adventive plants from ovules and nucelli in Citrus.

PubMed

Kochba, J; Spiegel-Roy, P; Safran, H

1972-09-01

1- to 8-week-old ovules and nucelli from three Citrus cultivars-Shamouti and Valencia (Citrus sinensis) oranges and Marsh Seedless (C. paradisi) grapefruit-were cultured in vitro. No embryo differentiation was observed in the explants prior to culture. The Shamouti ovules had degenerated and were apparently unfertilized. Embryoids formed on Murashige and Tucker nutrient medium supplemented with 500 mg/l malt extract. Whole plants developed on the same basal medium supplemented with kinetin and indole-3-acetic acid (IAA), coconut milk or gibberellic acid (GA3). A higher kinetin/IAA ratio or the addition of coconut milk favoured stem elongation more than root formation while a lower kinetin/IAA ratio favoured root formation and inhibited stem elongation. The addition of GA3 to the basal medium stimulated rooting and stem elongation. These results can be of aid in mutation research, allowing irradiation at stages prior to embryonic development.

Conserved Gene Expression Programs in Developing Roots from Diverse Plants.

PubMed

Huang, Ling; Schiefelbein, John

2015-08-01

The molecular basis for the origin and diversification of morphological adaptations is a central issue in evolutionary developmental biology. Here, we defined temporal transcript accumulation in developing roots from seven vascular plants, permitting a genome-wide comparative analysis of the molecular programs used by a single organ across diverse species. The resulting gene expression maps uncover significant similarity in the genes employed in roots and their developmental expression profiles. The detailed analysis of a subset of 133 genes known to be associated with root development in Arabidopsis thaliana indicates that most of these are used in all plant species. Strikingly, this was also true for root development in a lycophyte (Selaginella moellendorffii), which forms morphologically different roots and is thought to have evolved roots independently. Thus, despite vast differences in size and anatomy of roots from diverse plants, the basic molecular mechanisms employed during root formation appear to be conserved. This suggests that roots evolved in the two major vascular plant lineages either by parallel recruitment of largely the same developmental program or by elaboration of an existing root program in the common ancestor of vascular plants. © 2015 American Society of Plant Biologists. All rights reserved.

Fine Root Abundance and Dynamics of Stone Pine (Pinus cembra) at the Alpine Treeline Is Not Impaired by Self-shading.

PubMed

Kubisch, Petra; Leuschner, Christoph; Coners, Heinz; Gruber, Andreas; Hertel, Dietrich

2017-01-01

Low temperatures are crucial for the formation of the alpine treeline worldwide. Since soil temperature in the shade of tree canopies is lower than in open sites, it was assumed that self-shading may impair the trees' root growth performance. While experiments with tree saplings demonstrate root growth impairment at soil temperatures below 5-7°C, field studies exploring the soil temperature - root growth relationship at the treeline are missing. We recorded soil temperature and fine root abundance and dynamics in shaded and sun-exposed areas under canopies of isolated Pinus cembra trees at the alpine treeline. In contrast to the mentioned assumption, we found more fine root biomass and higher fine root growth in colder than in warmer soil areas. Moreover, colder areas showed higher fine root turnover and thus lower root lifespan than warmer places. We conclude that P. cembra balances enhanced fine root mortality in cold soils with higher fine root activity and by maintaining higher fine root biomass, most likely as a response to shortage in soil resource supply. The results from our study highlight the importance of in situ measurements on mature trees to understand the fine root response and carbon allocation pattern to the thermal growth conditions at the alpine treeline.

Trichoderma-Induced Acidification Is an Early Trigger for Changes in Arabidopsis Root Growth and Determines Fungal Phytostimulation

PubMed Central

Pelagio-Flores, Ramón; Esparza-Reynoso, Saraí; Garnica-Vergara, Amira; López-Bucio, José; Herrera-Estrella, Alfredo

2017-01-01

Trichoderma spp. are common rhizosphere inhabitants widely used as biological control agents and their role as plant growth promoting fungi has been established. Although soil pH influences several fungal and plant functional traits such as growth and nutrition, little is known about its influence in rhizospheric or mutualistic interactions. The role of pH in the Trichoderma–Arabidopsis interaction was studied by determining primary root growth and lateral root formation, root meristem status and cell viability, quiescent center (QC) integrity, and auxin inducible gene expression. Primary root growth phenotypes in wild type seedlings and STOP1 mutants allowed identification of a putative root pH sensing pathway likely operating in plant–fungus recognition. Acidification by Trichoderma induced auxin redistribution within Arabidopsis columella root cap cells, causing root tip bending and growth inhibition. Root growth stoppage correlated with decreased cell division and with the loss of QC integrity and cell viability, which were reversed by buffering the medium. In addition, stop1, an Arabidopsis mutant sensitive to low pH, was oversensitive to T. atroviride primary root growth repression, providing genetic evidence that a pH root sensing mechanism reprograms root architecture during the interaction. Our results indicate that root sensing of pH mediates the interaction of Trichoderma with plants. PMID:28567051

Comparative effects of plant growth regulators on leaf and stem explants of Labisia pumila var. alata

PubMed Central

Ling, Anna Pick Kiong; Tan, Kinn Poay; Hussein, Sobri

2013-01-01

Objective: Labisia pumila var. alata, commonly known as ‘Kacip Fatimah’ or ‘Selusuh Fatimah’ in Southeast Asia, is traditionally used by members of the Malay community because of its post-partum medicinal properties. Its various pharmaceutical applications cause an excessive harvesting and lead to serious shortage in natural habitat. Thus, this in vitro propagation study investigated the effects of different plant growth regulators (PGRs) on in vitro leaf and stem explants of L. pumila. Methods: The capabilities of callus, shoot, and root formation were evaluated by culturing both explants on Murashige and Skoog (MS) medium supplemented with various PGRs at the concentrations of 0, 1, 3, 5, and 7 mg/L. Results: Medium supplemented with 3 mg/L indole-3-butyric acid (IBA) showed the optimal callogenesis from both leaf and stem explants with (72.34±19.55)% and (70.40±14.14)% efficacy, respectively. IBA was also found to be the most efficient PGR for root induction. A total of (50.00±7.07)% and (77.78±16.47)% of root formation were obtained from the in vitro stem and leaf explants after being cultured for (26.5±5.0) and (30.0±8.5) d in the medium supplemented with 1 and 3 mg/L of IBA, respectively. Shoot formation was only observed in stem explant, with the maximum percentage of formation ((100.00±0.00)%) that was obtained in 1 mg/L zeatin after (11.0±2.8) d of culture. Conclusions: Callus, roots, and shoots can be induced from in vitro leaf and stem explants of L. pumila through the manipulation of types and concentrations of PGRs. PMID:23825148

In Situ Visualization of the Dynamics in Xylem Embolism Formation and Removal in the Absence of Root Pressure: A Study on Excised Grapevine Stems.

PubMed

Knipfer, Thorsten; Cuneo, Italo F; Brodersen, Craig R; McElrone, Andrew J

2016-06-01

Gas embolisms formed during drought can disrupt long-distance water transport through plant xylem vessels, but some species have the ability to remove these blockages. Despite evidence suggesting that embolism removal is linked to the presence of vessel-associated parenchyma, the underlying mechanism remains controversial and is thought to involve positive pressure generated by roots. Here, we used in situ x-ray microtomography on excised grapevine stems to determine if embolism removal is possible without root pressure, and if the embolism formation/removal affects vessel functional status after sample excision. Our data show that embolism removal in excised stems was driven by water droplet growth and was qualitatively identical to refilling in intact plants. When stem segments were rehydrated with H2O after excision, vessel refilling occurred rapidly (<1 h). The refilling process was substantially slower when polyethylene glycol was added to the H2O source, thereby providing new support for an osmotically driven refilling mechanism. In contrast, segments not supplied with H2O showed no refilling and increased embolism formation. Dynamic changes in liquid/wall contact angles indicated that the processes of embolism removal (i.e. vessel refilling) by water influx and embolism formation by water efflux were directly linked to the activity of vessel-associated living tissue. Overall, our results emphasize that root pressure is not required as a driving force for vessel refilling, and care should be taken when performing hydraulics measurements on excised plant organs containing living vessel-associated tissue, because the vessel behavior may not be static. © 2016 American Society of Plant Biologists. All Rights Reserved.

In Situ Visualization of the Dynamics in Xylem Embolism Formation and Removal in the Absence of Root Pressure: A Study on Excised Grapevine Stems1[OPEN

PubMed Central

Knipfer, Thorsten; Cuneo, Italo F.; Brodersen, Craig R.; McElrone, Andrew J.

2016-01-01

Gas embolisms formed during drought can disrupt long-distance water transport through plant xylem vessels, but some species have the ability to remove these blockages. Despite evidence suggesting that embolism removal is linked to the presence of vessel-associated parenchyma, the underlying mechanism remains controversial and is thought to involve positive pressure generated by roots. Here, we used in situ x-ray microtomography on excised grapevine stems to determine if embolism removal is possible without root pressure, and if the embolism formation/removal affects vessel functional status after sample excision. Our data show that embolism removal in excised stems was driven by water droplet growth and was qualitatively identical to refilling in intact plants. When stem segments were rehydrated with H2O after excision, vessel refilling occurred rapidly (<1 h). The refilling process was substantially slower when polyethylene glycol was added to the H2O source, thereby providing new support for an osmotically driven refilling mechanism. In contrast, segments not supplied with H2O showed no refilling and increased embolism formation. Dynamic changes in liquid/wall contact angles indicated that the processes of embolism removal (i.e. vessel refilling) by water influx and embolism formation by water efflux were directly linked to the activity of vessel-associated living tissue. Overall, our results emphasize that root pressure is not required as a driving force for vessel refilling, and care should be taken when performing hydraulics measurements on excised plant organs containing living vessel-associated tissue, because the vessel behavior may not be static. PMID:27208267

Role of LOTR1 in Nutrient Transport through Organization of Spatial Distribution of Root Endodermal Barriers.

PubMed

Li, Baohai; Kamiya, Takehiro; Kalmbach, Lothar; Yamagami, Mutsumi; Yamaguchi, Katsushi; Shigenobu, Shuji; Sawa, Shinichiro; Danku, John M C; Salt, David E; Geldner, Niko; Fujiwara, Toru

2017-03-06

The formation of Casparian strips and suberin lamellae at the endodermis limits the free diffusion of nutrients and harmful substances via the apoplastic space between the soil solution and the stele in roots [1-3]. Casparian strips are ring-like lignin polymers deposited in the middle of anticlinal cell walls between endodermal cells and fill the gap between them [4-6]. Suberin lamellae are glycerolipid polymers covering the endodermal cells and likely function as a barrier to limit transmembrane movement of apoplastic solutes into the endodermal cells [7, 8]. However, the current knowledge on the formation of these two distinct endodermal barriers and their regulatory role in nutrient transport is still limited. Here, we identify an uncharacterized gene, LOTR1, essential for Casparian strip formation in Arabidopsis thaliana. The lotr1 mutants display altered localization of CASP1, an essential protein for Casparian strip formation [9], disrupted Casparian strips, ectopic suberization of endodermal cells, and low accumulation of shoot calcium (Ca). Degradation by expression of a suberin-degrading enzyme in the mutants revealed that the ectopic suberization at the endodermal cells limits Ca transport through the transmembrane pathway, thereby causing reduced Ca delivery to the shoot. Moreover, analysis of the mutants showed that suberin lamellae function as an apoplastic diffusion barrier to the stele at sites of lateral root emergence where Casparian strips are disrupted. Our findings suggest that the transmembrane pathway through unsuberized endodermal cells, rather than the sites of lateral root emergence, mediates the transport of apoplastic substances such as Ca into the xylem. Copyright © 2017 Elsevier Ltd. All rights reserved.

Double Crush of L5 Spinal Nerve Root due to L4/5 Lateral Recess Stenosis and Bony Spur Formation of Lumbosacral Transitional Vertebra Pseudoarticulation: A Case Report and Review

PubMed Central

Iwasaki, Motoyuki; Akiyama, Masahiko; Koyanagi, Izumi; Niiya, Yoshimasa; Ihara, Tatsuo; Houkin, Kiyohiro

2017-01-01

We present a case of double-crushed L5 nerve root symptoms caused by inside and outside of the spinal canal with spur formation of the lumbosacral transitional vertebra (LSTV). A 78-year-old man presented with 7-year history of moderate paresis of his toe and left leg pain when walking. Magnetic resonance imaging (MRI) revealed spinal stenosis at the L3/4 and 4/5 spinal levels and he underwent wide fenestration of both levels. Leg pain disappeared and 6-min walk distance (6MWD) improved after surgery, however, the numbness in his toes increased and 6MWD decreased 9 months after surgery. Repeated MR and 3D multiplanar reconstructed computed tomography (CT) images showed extraforaminal impingement of the L5 root by bony spur of the left LSTV. He underwent second decompression surgery of the L5/S via the left sided Wiltse approach, resulting in the improvement of his symptoms. The impingement of L5 spinal nerve root between the transverse process of the fifth lumbar vertebra and the sacral ala is a rare entity of the pathology called “far-out syndrome (FOS)”. Especially, the bony spur formation secondary to the anomalous articulation of the LSTV (LSPA) has not been reported. These articulations could be due to severe disc degeneration, following closer distance and contact between the transverse process and the sacral ala. To our knowledge, this is the first report describing a case with this pathology and may be considered in cases of failed back surgery syndromes (FBSS) of the L5 root symptoms. PMID:29018654

Local and systemic mycorrhiza-induced protection against the ectoparasitic nematode Xiphinema index involves priming of defence gene responses in grapevine

PubMed Central

Hao, Zhipeng; Fayolle, Léon; van Tuinen, Diederik; Chatagnier, Odile; Gianinazzi, Silvio; Gianinazzi-Pearson, Vivienne

2012-01-01

The ectoparasitic dagger nematode (Xiphinema index), vector of Grapevine fanleaf virus (GFLV), provokes gall formation and can cause severe damage to the root system of grapevines. Mycorrhiza formation by Glomus (syn. Rhizophagus) intraradices BEG141 reduced both gall formation on roots of the grapevine rootstock SO4 (Vitis berlandieri×V. riparia) and nematode number in the surrounding soil. Suppressive effects increased with time and were greater when the nematode was post-inoculated rather than co-inoculated with the arbuscular mycorrhizal (AM) fungus. Using a split-root system, decreased X. index development was shown in mycorrhizal and non-mycorrhizal parts of mycorrhizal root systems, indicating that both local and systemic induced bioprotection mechanisms were active against the ectoparasitic nematode. Expression analyses of ESTs (expressed sequence tags) generated in an SSH (subtractive suppressive hybridization) library, representing plant genes up-regulated during mycorrhiza-induced control of X. index, and of described grapevine defence genes showed activation of chitinase 1b, pathogenesis-related 10, glutathione S-transferase, stilbene synthase 1, 5-enolpyruvyl shikimate-3-phosphate synthase, and a heat shock proein 70-interacting protein in association with the observed local and/or systemic induced bioprotection against the nematode. Overall, the data suggest priming of grapevine defence responses by the AM fungus and transmission of a plant-mediated signal to non-mycorrhizal tissues. Grapevine gene responses during AM-induced local and systemic bioprotection against X. index point to biological processes that are related either to direct effects on the nematode or to protection against nematode-imposed stress to maintain root tissue integrity. PMID:22407649

NSP-Dependent Simple Nitrile Formation Dominates upon Breakdown of Major Aliphatic Glucosinolates in Roots, Seeds, and Seedlings of Arabidopsis thaliana Columbia-0.

PubMed

Wittstock, Ute; Meier, Kathrin; Dörr, Friederike; Ravindran, Beena M

2016-01-01

One of the best-studied plant defense systems, the glucosinolate-myrosinase system of the Brassicales, is composed of thioglucosides known as glucosinolates and their hydrolytic enzymes, the myrosinases. Tissue disruption brings these components together, and bioactive products are formed as a consequence of myrosinase-catalyzed glucosinolate hydrolysis. Among these products, isothiocyanates have attracted most interest as chemical plant defenses against herbivores and pathogens and health-promoting compounds in the human diet. Previous research has identified specifier proteins whose presence results in the formation of alternative product types, e.g., nitriles, at the expense of isothiocyanates. The biological roles of specifier proteins and alternative breakdown products are poorly understood. Here, we assessed glucosinolate breakdown product profiles obtained upon maceration of roots, seedlings and seeds of Arabidopsis thaliana Columbia-0. We identified simple nitriles as the predominant breakdown products of the major endogenous aliphatic glucosinolates in root, seed, and seedling homogenates. In agreement with this finding, genes encoding nitrile-specifier proteins (NSPs) are expressed in roots, seeds, and seedlings. Analysis of glucosinolate breakdown in mutants with T-DNA insertions in any of the five NSP genes demonstrated, that simple nitrile formation upon tissue disruption depended almost entirely on NSP2 in seeds and mainly on NSP1 in seedlings. In roots, about 70-80% of the nitrile-forming activity was due to NSP1 and NSP3 . Thus, glucosinolate breakdown product profiles are organ-specifically regulated in A. thaliana Col-0, and high proportions of simple nitriles are formed in some parts of the plant. This should be considered in future studies on biological roles of the glucosinolate-myrosinase system.

NSP-Dependent Simple Nitrile Formation Dominates upon Breakdown of Major Aliphatic Glucosinolates in Roots, Seeds, and Seedlings of Arabidopsis thaliana Columbia-0

PubMed Central

Wittstock, Ute; Meier, Kathrin; Dörr, Friederike; Ravindran, Beena M.

2016-01-01

One of the best-studied plant defense systems, the glucosinolate-myrosinase system of the Brassicales, is composed of thioglucosides known as glucosinolates and their hydrolytic enzymes, the myrosinases. Tissue disruption brings these components together, and bioactive products are formed as a consequence of myrosinase-catalyzed glucosinolate hydrolysis. Among these products, isothiocyanates have attracted most interest as chemical plant defenses against herbivores and pathogens and health-promoting compounds in the human diet. Previous research has identified specifier proteins whose presence results in the formation of alternative product types, e.g., nitriles, at the expense of isothiocyanates. The biological roles of specifier proteins and alternative breakdown products are poorly understood. Here, we assessed glucosinolate breakdown product profiles obtained upon maceration of roots, seedlings and seeds of Arabidopsis thaliana Columbia-0. We identified simple nitriles as the predominant breakdown products of the major endogenous aliphatic glucosinolates in root, seed, and seedling homogenates. In agreement with this finding, genes encoding nitrile-specifier proteins (NSPs) are expressed in roots, seeds, and seedlings. Analysis of glucosinolate breakdown in mutants with T-DNA insertions in any of the five NSP genes demonstrated, that simple nitrile formation upon tissue disruption depended almost entirely on NSP2 in seeds and mainly on NSP1 in seedlings. In roots, about 70–80% of the nitrile-forming activity was due to NSP1 and NSP3. Thus, glucosinolate breakdown product profiles are organ-specifically regulated in A. thaliana Col-0, and high proportions of simple nitriles are formed in some parts of the plant. This should be considered in future studies on biological roles of the glucosinolate-myrosinase system. PMID:27990154

Effect of Exogenous Indole-3-Acetic Acid and Indole-3-Butyric Acid on Internal Levels of the Respective Auxins and Their Conjugation with Aspartic Acid during Adventitious Root Formation in Pea Cuttings

PubMed Central

Nordström, Ann-Caroline; Jacobs, Fernando Alvarado; Eliasson, Lennart

1991-01-01

The influence of exogenous indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on the internal levels of these auxins was studied during the first 4 days of adventitious root formation in cuttings of Pisum sativum L. The quantitations were done by high performance liquid chromatography with spectrofluorometric detection. IBA, identified by combined gas chromatography-mass spectrometry (GC-MS), was found to naturally occur in this plant material. The root inducing ability of exogenous IBA was superior to that of IAA. The IAA level in the tissue increased considerably on the first day after application of IAA, but rapidly decreased again, returning to a level twice the control by day 3. The predominant metabolic route was conjugation with aspartic acid, as reflected by the increase in the level of indole-3-acetylaspartic acid. The IBA treatment resulted in increases in the levels of IBA, IAA, and indole-3-acetylaspartic acid. The IAA content rapidly returned to control levels, whereas the IBA level remained high throughout the experimental period. High amounts of indole-3-butyrylaspartic acid were found in the tissue after feeding with IBA. The identity of the conjugate was confirmed by 1H-nuclear magnetic resonance and GC-MS. IBA was much more stable in solution than IAA. No IAA was detected after 48 hours, whereas 70% IBA was still recovered after this time. The relatively higher root inducing ability of IBA is ascribed to the fact that its level remained elevated longer than that of IAA, even though IBA was metabolized in the tissue. Adventitious root formation is discussed on the basis of these findings. PMID:16668265

Protection forest resilience after a fire event: a case study in Vallis, Switzerland

NASA Astrophysics Data System (ADS)

Vergani, Chiara; Werlen, Mario; Schwarz, Massimiliano

2016-04-01

Forests are well known to protect against natural hazards such as landslides, rockfall and floods. Nevertheless, they are dynamic ecosystems which are exposed to a variety of disturbances such as windstorms, fires, bark beetle and pathogen outbreaks. Catastrophic disturbances like windstorms and fires usually remove large portions of the canopy, starting a succession process which lead to a complete stand regeneration. Disturbances belong to the natural dynamic of forests, however they are highly undesirable in the case where forest protect infrastructure or settlements. Quantifying the decay and recovery of the protection effect of forests after disturbances is therefore important to evaluate risks and implement appropriate management techniques, when needed. This work analyzes the dynamic of a Scots Pine (Pinus silvestris) protection forests near Visp (Vallis) after a fire event, focusing on root reinforcement, which is the key factor in preventing shallow landslides. Forest cover, root distribution and root mechanical properties were analyzed 4 years after the fire event, and the root reinforcement has been quantified. Furthermore, the contribution of natural regeneration has been evaluated. Results show that the root reinforcement of Scots pine has declined massively in the forest fire area. At a distance of 1.5 m from the tree stem there is a reduction of 60% compared with the live stand. With increasing distance from the stem, the reduction in the reinforcement is even bigger. At a distance of 2.5 meters it is 12% and at 3.5 meters, only 5% of the original root reinforcement. This decrease is due to the decomposition of roots and associated change in the mechanical properties of the wood. The reinforcement of the dead roots in the forest area is estimated between 0.36 kPa and 2.64 kPa. The contribution of the emerging regeneration is estimated on average 0.01 kPa. Overall the stand provides a reinforcement between 0.37 kPa and 2.65 kPa. From the results it can be concluded that the dying roots can still provide a certain root reinforcement; however, the contribution of rejuvenation is too little to compensate the continuously decreasing protective effect in the future time. The time in which a forest can return in the initial state plays therefore a decisive role for contrasting the formation of landslides, which after a forest fire can be triggered at lower precipitation events. The results obtained need now to be implemented in slope stability analysis to compare the protection effect of vegetation before and after the disturbance. This work contributes to provide a first framework to evaluate the efficiency of protection forests before and after a catastrophic event, in order to support risk evaluation and plan possible management actions.

Rrhizogenesis in vitro is a convenient model for studying the root graviperceptive apparatus formation in microgravity

NASA Astrophysics Data System (ADS)

Kordyum, Elizabeth; Sarnatska, Veresa; Ovcharenko, Yulia

A root graviperceptive apparatus is known to form in microgravity but does not function in the absence of a gravitational vector, that has been shown in many spaceflight experiments with seedlings of different plant species. In statocytes, which are differentiated in microgravity, a nucleus is localized in the proximal part of a cell as at 1 g. Unlike control, amyloplastsstatoliths do not sedimented in the distal part of a cell in microgravity, they group in the cell center more often, sometimes they localized in the different part of a cell. In all these experiments, the objects of investigations were embryonal roots formed in seeds at 1 g. There is only single report that columella cells in roots, which developed de novo from callus in space flight, did not differentiate in statocytes. Therefore, we call to attention to rhizogenesis in vitro as a convenient model for studying the influence of microgravity on differentiation of a root graviperceptive apparatus. Two methods for obtaining of Arabidopsis thaliana roots in vitro are proposed: the first-from the primary callus of leaf origin and the second - from leaf fragments. Callus initiation and growth are successful on MS medium supplemented with vitamin B5, glycine, inositol, 2,4-D, kinetin, glucose and agar. For induction of rhizogenesis calli were transferred to medium without hormones or medium which contained one to ten of MS mineral salts and microelements, without vitamins and hormones. Rhyzogenesis was obtained without added growth substances, but considerably higher number of calli with roots and number of roots per callus are on MS medium diluted tenfold. Rhizogenesis in A. thaliana leaf segments should present no problem, but the most intensive root formation is obtained when culturing them for three day on diluted MS medium supplemented with salycilic acid and then on diluted MS medium only. The low temperature treatment for three days increases the number of roots formed. A role of both plasticity and positional keys in vivo and in vitro root development at 1 g and under clinorotation is discussed.

Simulation of root forms using cellular automata model

NASA Astrophysics Data System (ADS)

Winarno, Nanang; Prima, Eka Cahya; Afifah, Ratih Mega Ayu

2016-02-01

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled "A New Kind of Science" discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram's investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation used four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.

Functional Heart Valve Scaffolds Obtained by Complete Decellularization of Porcine Aortic Roots in a Novel Differential Pressure Gradient Perfusion System

PubMed Central

Sierad, Leslie Neil; Shaw, Eliza Laine; Bina, Alexander; Brazile, Bryn; Rierson, Nicholas; Patnaik, Sourav S.; Kennamer, Allison; Odum, Rebekah; Cotoi, Ovidiu; Terezia, Preda; Branzaniuc, Klara; Smallwood, Harrison; Deac, Radu; Egyed, Imre; Pavai, Zoltan; Szanto, Annamaria; Harceaga, Lucian; Suciu, Horatiu; Raicea, Victor; Olah, Peter; Simionescu, Agneta; Liao, Jun; Movileanu, Ionela

2015-01-01

There is a great need for living valve replacements for patients of all ages. Such constructs could be built by tissue engineering, with perspective of the unique structure and biology of the aortic root. The aortic valve root is composed of several different tissues, and careful structural and functional consideration has to be given to each segment and component. Previous work has shown that immersion techniques are inadequate for whole-root decellularization, with the aortic wall segment being particularly resistant to decellularization. The aim of this study was to develop a differential pressure gradient perfusion system capable of being rigorous enough to decellularize the aortic root wall while gentle enough to preserve the integrity of the cusps. Fresh porcine aortic roots have been subjected to various regimens of perfusion decellularization using detergents and enzymes and results compared to immersion decellularized roots. Success criteria for evaluation of each root segment (cusp, muscle, sinus, wall) for decellularization completeness, tissue integrity, and valve functionality were defined using complementary methods of cell analysis (histology with nuclear and matrix stains and DNA analysis), biomechanics (biaxial and bending tests), and physiologic heart valve bioreactor testing (with advanced image analysis of open–close cycles and geometric orifice area measurement). Fully acellular porcine roots treated with the optimized method exhibited preserved macroscopic structures and microscopic matrix components, which translated into conserved anisotropic mechanical properties, including bending and excellent valve functionality when tested in aortic flow and pressure conditions. This study highlighted the importance of (1) adapting decellularization methods to specific target tissues, (2) combining several methods of cell analysis compared to relying solely on histology, (3) developing relevant valve-specific mechanical tests, and (4) in vitro testing of valve functionality. PMID:26467108

Autotransplantation of a maxillary third molar to replace a maxillary premolar with vertical root fracture.

PubMed

Tsurumachi, T; Kakehashi, Y

2007-12-01

To report the successful autotransplantation of a fully developed third molar that required nonsurgical and surgical interventions for tooth adaptation. This case report describes the autotransplantation of a third molar with complete root development after the loss of a fractured premolar in a 47-year-old male. To allow better adaptation of the donor tooth, the buccal roots of the third molar were removed using a diamond bur and the canal entrances were filled. Recall examination 6 years after completion of root-canal treatment showed normal periodontal healing with absence of infection, ankylosis or progressive resorption. The transplantation of a third molar is seen as a promising method to replace a lost permanent tooth, and to restore aesthetics and function. *Autotransplantation is a viable option for the treatment of a missing tooth or for replacement of traumatized tooth when there is a donor tooth available. *Fully developed third molars are potentially reliable candidates in the absence of other suitable donor teeth.

Neoformation of clay in lateral root catchments of mallee eucalypts: a chemical perspective

PubMed Central

Verboom, William H.; Pate, John S.; Aspandiar, Mehrooz

2010-01-01

Background and Aims A previous paper (Annals of Botany 103: 673–685) described formation of clayey pavements in lateral root catchments of eucalypts colonizing a recently formed sand dune in south-west Western Australia. Here chemical and morphological aspects of their formation at the site are studied. Methods Chemical and physical examinations of soil cores through pavements and sand under adjacent heath assessed build-up of salts, clay and pH changes in or below pavements. Relationships of root morphology to clay deposition were examined and deposits subjected to scanning electron microscopy and energy-dispersive X-ray analysis. Xylem transport of mineral elements in eucalypt and non-eucalypt species was studied by analysis of xylem (tracheal) sap from lateral roots. Key Results The columns of which pavements are composed develop exclusively on lower-tier lateral roots. Such sites show intimate associations of fine roots, fungal filaments, microbiota and clay deposits rich in Si, Al and Fe. Time scales for construction of pavements by eucalypts were assessed. Cores through columns of pavemented profiles showed gross elevations of bulk density, Al, Fe and Si in columns and related increases in pH, Mg and Ca status in lower profiles. A cutting through the dune exhibited pronounced alkalinity (pH 7–10) under mallee woodland versus acidity (pH 5–6·5) under proteaceous heath. Xylem sap analyses showed unusually high concentrations of Al, Fe, Mg and Si in dry-season samples from column-bearing roots. Conclusions Deposition of Al–Fe–Si-rich clay is pivotal to pavement construction by eucalypts and leads to profound chemical and physical changes in relevant soil profiles. Microbial associates of roots are likely to be involved in clay genesis, with parent eucalypts supplying the required key mineral elements and carbon sources. Acquisition of the Al and Fe incorporated into clay derives principally from hydraulic uplift from ground water via deeply penetrating tap roots. PMID:19897459

Root length in the permanent teeth of women with an additional X chromosome (47,XXX females).

PubMed

Lähdesmäki, Raija E; Alvesalo, Lassi J

2010-07-01

Previous studies have demonstrated differential effects of the X and Y chromosomes on dental development. The expression of sexual dimorphism in terms of tooth size, shape, number and developmental timing has been explained especially by Y chromosome influence. The Y chromosome promotes enamel, crown and root dentin development. The X chromosome has an effect on enamel deposition. The aim of this research is to study the influence of the extra X chromosome on the development of permanent tooth root length. The study subjects (all of whom were from the Kvantti Dental Research Project) were seven 47,XXX females, five female relatives and 51 and 52 population control men and women, respectively. Measurements were made from panoramic radiographs on available permanent teeth by a digital calliper according to established procedures. The results showed that the maxillary root lengths of the 47,XXX females were of the same magnitude as those in normal women, but the mandibular root lengths were longer in 47,XXX females than in normal men or women. Increased enamel thickness in the teeth of 47,XXX females is apparently caused by the active enamel gene in all X chromosomes having no increased influence on crown dentin formation. These results in 47,XXX females indicate an increase in root dentin development, at least in the mandible, which together with the data on crown formation reflects a continuous long-lasting effect of the X chromosome on dental development.

Complete disintegration of the microtubular cytoskeleton precedes its auxin-mediated reconstruction in postmitotic maize root cells

NASA Technical Reports Server (NTRS)

Baluska, F.; Barlow, P. W.; Volkmann, D.

1996-01-01

The inhibitory action of 0.1 microM auxin (IAA) on maize root growth was closely associated with a rapid and complete disintegration of the microtubular (MT) cytoskeleton, as visualized by indirect immunofluorescence of tubulin, throughout the growth region. After 30 min of this treatment, only fluorescent spots were present in root cells, accumulating either around nuclei or along cell walls. Six h later, in addition to some background fluorescence, dense but partially oriented oblique or longitudinal arrays of cortical MTs (CMTs) were found in most growing cells of the root apex. After 24 h of treatment, maize roots had adapted to the auxin, as inferred from the slowly recovering elongation rate and from the reassembly of a dense and well-ordered MT cytoskeleton which showed only slight deviations from that of the control root cells. Taxol pretreatment (100 microM, 24 h) prevented not only the rapid auxin-mediated disintegration of the MT cytoskeleton but also a reorientation of the CMT arrays, from transversal to longitudinal. The only tissue to show MTs in their cells throughout the auxin treatment was the epidermis. Significant resistance of transverse CMT arrays in these cells towards auxin was confirmed using a higher auxin concentration (100 microM, 24 h). The latter auxin dose also revealed inter-tissue-specific responses to auxin: outer cortical cell files reoriented their CMTs from the transversal to longitudinal orientation, whereas inner cortical cell files lost their MTs. This high auxin-mediated response, associated with the swelling of root apices, was abolished with the pretreatment of maize root with taxol.

ROOT — A C++ framework for petabyte data storage, statistical analysis and visualization

NASA Astrophysics Data System (ADS)

Antcheva, I.; Ballintijn, M.; Bellenot, B.; Biskup, M.; Brun, R.; Buncic, N.; Canal, Ph.; Casadei, D.; Couet, O.; Fine, V.; Franco, L.; Ganis, G.; Gheata, A.; Maline, D. Gonzalez; Goto, M.; Iwaszkiewicz, J.; Kreshuk, A.; Segura, D. Marcos; Maunder, R.; Moneta, L.; Naumann, A.; Offermann, E.; Onuchin, V.; Panacek, S.; Rademakers, F.; Russo, P.; Tadel, M.

2009-12-01

ROOT is an object-oriented C++ framework conceived in the high-energy physics (HEP) community, designed for storing and analyzing petabytes of data in an efficient way. Any instance of a C++ class can be stored into a ROOT file in a machine-independent compressed binary format. In ROOT the TTree object container is optimized for statistical data analysis over very large data sets by using vertical data storage techniques. These containers can span a large number of files on local disks, the web, or a number of different shared file systems. In order to analyze this data, the user can chose out of a wide set of mathematical and statistical functions, including linear algebra classes, numerical algorithms such as integration and minimization, and various methods for performing regression analysis (fitting). In particular, the RooFit package allows the user to perform complex data modeling and fitting while the RooStats library provides abstractions and implementations for advanced statistical tools. Multivariate classification methods based on machine learning techniques are available via the TMVA package. A central piece in these analysis tools are the histogram classes which provide binning of one- and multi-dimensional data. Results can be saved in high-quality graphical formats like Postscript and PDF or in bitmap formats like JPG or GIF. The result can also be stored into ROOT macros that allow a full recreation and rework of the graphics. Users typically create their analysis macros step by step, making use of the interactive C++ interpreter CINT, while running over small data samples. Once the development is finished, they can run these macros at full compiled speed over large data sets, using on-the-fly compilation, or by creating a stand-alone batch program. Finally, if processing farms are available, the user can reduce the execution time of intrinsically parallel tasks — e.g. data mining in HEP — by using PROOF, which will take care of optimally distributing the work over the available resources in a transparent way. Program summaryProgram title: ROOT Catalogue identifier: AEFA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFA_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: LGPL No. of lines in distributed program, including test data, etc.: 3 044 581 No. of bytes in distributed program, including test data, etc.: 36 325 133 Distribution format: tar.gz Programming language: C++ Computer: Intel i386, Intel x86-64, Motorola PPC, Sun Sparc, HP PA-RISC Operating system: GNU/Linux, Windows XP/Vista, Mac OS X, FreeBSD, OpenBSD, Solaris, HP-UX, AIX Has the code been vectorized or parallelized?: Yes RAM:>55 Mbytes Classification: 4, 9, 11.9, 14 Nature of problem: Storage, analysis and visualization of scientific data Solution method: Object store, wide range of analysis algorithms and visualization methods Additional comments: For an up-to-date author list see: http://root.cern.ch/drupal/content/root-development-team and http://root.cern.ch/drupal/content/former-root-developers Running time: Depending on the data size and complexity of analysis algorithms References:http://root.cern.ch.

Identification and characterization of terpene synthases potentially involved in the formation of volatile terpenes in carrot (Daucus carota L.) roots

USDA-ARS?s Scientific Manuscript database

Plants produce numerous volatile organic compounds, which are important in determining the quality and nutraceutical properties of fruit and root crops, including the taste and the aroma of carrots (Daucus carota L.). A combined chemical, biochemical and molecular study was conducted to evaluate the...

Geometrical modeling of complete dental shapes by using panoramic X-ray, digital mouth data and anatomical templates.

PubMed

Barone, Sandro; Paoli, Alessandro; Razionale, Armando Viviano

2015-07-01

In the field of orthodontic planning, the creation of a complete digital dental model to simulate and predict treatments is of utmost importance. Nowadays, orthodontists use panoramic radiographs (PAN) and dental crown representations obtained by optical scanning. However, these data do not contain any 3D information regarding tooth root geometries. A reliable orthodontic treatment should instead take into account entire geometrical models of dental shapes in order to better predict tooth movements. This paper presents a methodology to create complete 3D patient dental anatomies by combining digital mouth models and panoramic radiographs. The modeling process is based on using crown surfaces, reconstructed by optical scanning, and root geometries, obtained by adapting anatomical CAD templates over patient specific information extracted from radiographic data. The radiographic process is virtually replicated on crown digital geometries through the Discrete Radon Transform (DRT). The resulting virtual PAN image is used to integrate the actual radiographic data and the digital mouth model. This procedure provides the root references on the 3D digital crown models, which guide a shape adjustment of the dental CAD templates. The entire geometrical models are finally created by merging dental crowns, captured by optical scanning, and root geometries, obtained from the CAD templates. Copyright © 2015 Elsevier Ltd. All rights reserved.

MADS-box transcription factor AGL21 regulates lateral root development and responds to multiple external and physiological signals.

PubMed

Yu, Lin-Hui; Miao, Zi-Qing; Qi, Guo-Feng; Wu, Jie; Cai, Xiao-Teng; Mao, Jie-Li; Xiang, Cheng-Bin

2014-11-01

Plant root system morphology is dramatically influenced by various environmental cues. The adaptation of root system architecture to environmental constraints, which mostly depends on the formation and growth of lateral roots, is an important agronomic trait. Lateral root development is regulated by the external signals coordinating closely with intrinsic signaling pathways. MADS-box transcription factors are known key regulators of the transition to flowering and flower development. However, their functions in root development are still poorly understood. Here we report that AGL21, an AGL17-clade MADS-box gene, plays a crucial role in lateral root development. AGL21 was highly expressed in root, particularly in the root central cylinder and lateral root primordia. AGL21 overexpression plants produced more and longer lateral roots while agl21 mutants showed impaired lateral root development, especially under nitrogen-deficient conditions. AGL21 was induced by many plant hormones and environmental stresses, suggesting a function of this gene in root system plasticity in response to various signals. Furthermore, AGL21 was found positively regulating auxin accumulation in lateral root primordia and lateral roots by enhancing local auxin biosynthesis, thus stimulating lateral root initiation and growth. We propose that AGL21 may be involved in various environmental and physiological signals-mediated lateral root development and growth. © The Author 2014. Published by Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

Generation of alkali-free and high-proton concentration layer in a soda lime glass using non-contact corona discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikeda, Hiroshi; Sakai, Daisuke; Nishii, Junji

2013-08-14

Formation mechanisms of alkali-free and high-proton concentration surfaces were investigated for a soda lime glass using a corona discharge treatment under an atmospheric pressure. Protons produced by high DC voltage around an anode needle electrode were incorporated into a sodium ion site in the anode side glass. The sodium ion was swept away to the cathode side as a charge carrier. Then it was discharged. The precipitated sodium was transformed to a Na{sub 2}CO{sub 3} powder when the surface contacted with air. The sodium ion in the glass surface layer of the anode side was replaced completely by protons. Themore » concentration of OH groups in the layer was balanced with the amount of excluded sodium ions. The substitution reaction of sodium ions with protons tends to be saturated according to a square root function of time. The alkali depletion layer formation rate was affected by the large difference in mobility between sodium ions and protons in the glass.« less

Endodontic management of maxillary first molar with seven root canals diagnosed using Cone Beam Computed Tomography scanning

PubMed Central

Raghavendra, Srinidhi Surya; Hindlekar, Ajit Narayan; Desai, Niranjan Nanasaheb; Vyavahare, Nishant Kishor; Napte, Bandu Devrao

2014-01-01

The main objective of root canal treatment is thorough cleaning and shaping of the entire pulp space and its complete filling with an inert filling material. A major cause of post-treatment disease is the inability to locate, debride or adequately fill all canals of the root canal system. The form, configuration, and number of root canals in the maxillary first molars have been discussed for more than half a century. Maxillary first molars commonly present with three roots and three canals, with a second mesiobuccal canal (MB2) also present. With the advent of improved magnification there are reports of multiple root canals in the maxillary first molars. Nonsurgical endodontic therapy of a left maxillary first molar with three roots and seven root canals was successfully performed under a dental operating microscope. The diagnosis of multiple root canals was confirmed with the help of Cone Beam Computed Tomography (CBCT) images. PMID:25565745

Arabidopsis SHR and SCR transcription factors and AUX1 auxin influx carrier control the switch between adventitious rooting and xylogenesis in planta and in in vitro cultured thin cell layers.

PubMed

Della Rovere, F; Fattorini, L; D'Angeli, S; Veloccia, A; Del Duca, S; Cai, G; Falasca, G; Altamura, M M

2015-03-01

Adventitious roots (ARs) are essential for vegetative propagation. The Arabidopsis thaliana transcription factors SHORT ROOT (SHR) and SCARECROW (SCR) affect primary/lateral root development, but their involvement in AR formation is uncertain. LAX3 and AUX1 auxin influx carriers contribute to primary/lateral root development. LAX3 expression is regulated by SHR, and LAX3 contributes to AR tip auxin maximum. In contrast, AUX1 involvement in AR development is unknown. Xylogenesis is induced by auxin plus cytokinin as is AR formation, but the genes involved are largely unknown. Stem thin cell layers (TCLs) form ARs and undergo xylogenesis under the same auxin plus cytokinin input. The aim of this research was to investigate SHR, SCR, AUX1 and LAX3 involvement in AR formation and xylogenesis in intact hypocotyls and stem TCLs in arabidopsis. Hypocotyls of scr-1, shr-1, lax3, aux1-21 and lax3/aux1-21 Arabidopsis thaliana null mutant seedlings grown with or without auxin plus cytokinin were examined histologically, as were stem TCLs cultured with auxin plus cytokinin. SCR and AUX1 expression was monitored using pSCR::GFP and AUX1::GUS lines, and LAX3 expression and auxin localization during xylogenesis were monitored by using LAX3::GUS and DR5::GUS lines. AR formation was inhibited in all mutants, except lax3. SCR was expressed in pericycle anticlinally derived AR-forming cells of intact hypocotyls, and in cell clumps forming AR meristemoids of TCLs. The apex was anomalous in shr and scr ARs. In all mutant hypocotyls, the pericycle divided periclinally to produce xylogenesis. Xylary element maturation was favoured by auxin plus cytokinin in shr and aux1-21. Xylogenesis was enhanced in TCLs, and in aux1-21 and shr in particular. AUX1 was expressed before LAX3, i.e. in the early derivatives leading to either ARs or xylogenesis. AR formation and xylogenesis are developmental programmes that are inversely related, but they involve fine-tuning by the same proteins, namely SHR, SCR and AUX1. Pericycle activity is central for the equilibrium between xylary development and AR formation in the hypocotyl, with a role for AUX1 in switching between, and balancing of, the two developmental programmes. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company.

Topographic and Roughness Characteristics of the Vastitas Borealis Formation on Mars Described by Fractal Statistics

NASA Technical Reports Server (NTRS)

Garneau, S.; Plaut, J. J.

2000-01-01

The surface roughness of the Vastitas Borealis Formation on Mars was analyzed with fractal statistics. Root mean square slopes and fractal dimensions were calculated for 74 topographic profiles. Results have implications for radar scattering models.

Light Requirement for Shoot Regeneration in Horseradish Hairy Roots 1

PubMed Central

Saitou, Tsutomu; Kamada, Hiroshi; Harada, Hiroshi

1992-01-01

Hairy roots of horseradish (Armoracia rusticana) were induced by inoculation with Agrobacterium rhizogenes harboring Ri plasmid and cultured on phytohormone-free Murashige and Skoog medium after eliminating the bacteria. Hairy roots grew vigorously and sometimes formed yellowish calli under dark conditions. On the other hand, growth of hairy roots stopped after several weeks of culture with light, then shoots were regenerated. Frequency of shoot formation from hairy roots increased as the culture period in light lengthened and the light intensity increased. The shoot regeneration was induced by treatment with white or red light, but not with far-red light. Shoot regeneration by red light was inhibited by following treatment with far-red light. Red and far-red light reversibly affected shoot regeneration. Excised roots of nontransformed plants grew quite slowly on phytohormone-free Murashige and Skoog medium and occasionally formed shoots under white light conditions. PMID:16669041

Light requirement for shoot regeneration in horseradish hairy roots.

PubMed

Saitou, T; Kamada, H; Harada, H

1992-08-01

Hairy roots of horseradish (Armoracia rusticana) were induced by inoculation with Agrobacterium rhizogenes harboring Ri plasmid and cultured on phytohormone-free Murashige and Skoog medium after eliminating the bacteria. Hairy roots grew vigorously and sometimes formed yellowish calli under dark conditions. On the other hand, growth of hairy roots stopped after several weeks of culture with light, then shoots were regenerated. Frequency of shoot formation from hairy roots increased as the culture period in light lengthened and the light intensity increased. The shoot regeneration was induced by treatment with white or red light, but not with far-red light. Shoot regeneration by red light was inhibited by following treatment with far-red light. Red and far-red light reversibly affected shoot regeneration. Excised roots of nontransformed plants grew quite slowly on phytohormone-free Murashige and Skoog medium and occasionally formed shoots under white light conditions.

Effects of light on protein patterns in gravitropically stimulated root caps of corn

NASA Technical Reports Server (NTRS)

Feldman, L. J.; Gildow, V.

1984-01-01

In certain cultivars of corn (Zea mays var. Merit), light stimulates gravitropic bending of the root by influencing events in the root cap. In this paper, we report on changes in root cap proteins which occur as a result of the light treatment and single out specific proteins as potentially having a role in mediating the gravitropic response. For this work, we have used root caps maintained aseptically in culture media supplemented with auxin. If auxin is deleted from the culture medium, the protein profiles observed following illumination differ from that seen in caps provided light while in auxin-supplemented media. We also report that several of the proteins for which synthesis is stimulated by light appear to turn over rapidly, usually within 0.5 hour of formation.

Rhizoctonia crown and root rot disease nursery

USDA-ARS?s Scientific Manuscript database

The BSDF cooperative CRR Eastern Evaluation Nursery Rhizoctonia crown and root rot Evaluation Nursery in 2016 was a randomized complete-block design with five replications in 15 feet long, one-row plots (20 in row spacing), at the Saginaw Valley Research and Education Center near Frankenmuth, MI. F...

CEP genes regulate root and shoot development in response to environmental cues and are specific to seed plants.

PubMed

Delay, Christina; Imin, Nijat; Djordjevic, Michael A

2013-12-01

The manifestation of repetitive developmental programmes during plant growth can be adjusted in response to various environmental cues. During root development, this means being able to precisely control root growth and lateral root development. Small signalling peptides have been found to play roles in many aspects of root development. One member of the CEP (C-TERMINALLY ENCODED PEPTIDE) gene family has been shown to arrest root growth. Here we report that CEP genes are widespread among seed plants but are not present in land plants that lack true branching roots or root vasculature. We have identified 10 additional CEP genes in Arabidopsis. Expression analysis revealed that CEP genes are regulated by environmental cues such as nitrogen limitation, increased salt levels, increased osmotic strength, and increased CO2 levels in both roots and shoots. Analysis of synthetic CEP variants showed that both peptide sequence and modifications of key amino acids affect CEP biological activity. Analysis of several CEP over-expression lines revealed distinct roles for CEP genes in root and shoot development. A cep3 knockout mutant showed increased root and shoot growth under a range of abiotic stress, nutrient, and light conditions. We demonstrate that CEPs are negative regulators of root development, slowing primary root growth and reducing lateral root formation. We propose that CEPs are negative regulators that mediate environmental influences on plant development.

Interactive effects of phosphorus deficiency and exogenous auxin on root morphological and physiological traits in white lupin (Lupinus albus L.).

PubMed

Tang, Hongliang; Shen, Jianbo; Zhang, Fusuo; Rengel, Zed

2013-04-01

White lupin (Lupinus albus) exhibits strong root morphological and physiological responses to phosphorus (P) deficiency and auxin treatments, but the interactive effects of P and auxin in regulating root morphological and physiological traits are not fully understood. This study aimed to assess white lupin root traits as influenced by P (0 or 250 μmol L(-1)) and auxin (10(-8) mol L(-1) NAA) in nutrient solution. Both P deficiency and auxin treatments significantly altered root morphological traits, as evidenced by reduced taproot length, increased number and density of first-order lateral roots, and enhanced cluster-root formation. Changes in root physiological traits were also observed, i.e., increased proton, citrate, and acid phosphatase exudation. Exogenous auxin enhanced root responses and sensitivity to P deficiency. A significant interplay exists between P and auxin in the regulation of root morphological and physiological traits. Principal component analysis showed that P availability explained 64.8% and auxin addition 21.3% of the total variation in root trait parameters, indicating that P availability is much more important than auxin in modifying root responses of white lupin. This suggests that white lupin can coordinate root morphological and physiological responses to enhance acquisition of P resources, with an optimal trade-off between root morphological and physiological traits regulated by external stimuli such as P availability and auxin.

Effects of GhWUS from upland cotton (Gossypium hirsutum L.) on somatic embryogenesis and shoot regeneration.

PubMed

Xiao, Yanqing; Chen, Yanli; Ding, Yanpeng; Wu, Jie; Wang, Peng; Yu, Ya; Wei, Xi; Wang, Ye; Zhang, Chaojun; Li, Fuguang; Ge, Xiaoyang

2018-05-01

The WUSCHEL (WUS) gene encodes a plant-specific homeodomain-containing transcriptional regulator, which plays important roles during embryogenesis, as well as in the formation of shoot and flower meristems. Here, we isolated two homologues of Arabidopsis thaliana WUS (AtWUS), GhWUS1a_At and GhWUS1b_At, from upland cotton (Gossypium hirsutum). Domain analysis suggested that the two putative GhWUS proteins contained a highly conserved DNA-binding HOX domain and a WUS-box. Expression profile analysis showed that GhWUSs were predominantly expressed during the embryoid stage. Ectopic expression of GhWUSs in Arabidopsis could induce somatic embryo and shoot formation from seedling root tips. Furthermore, in the absence of exogenous hormone, overexpression of GhWUSs in Arabidopsis could promote shoot regeneration from excised roots, and in the presence of exogenous auxin, excised roots expressing GhWUS could be induced to produce somatic embryo. In addition, expression of the chimeric GhWUS repressor in cotton callus inhibited embryogenic callus formation. Our results show that GhWUS is an important regulator of somatic embryogenesis and shoot regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

The promoter of the Arabidopsis PIN6 auxin transporter enabled strong expression in the vasculature of roots, leaves, floral stems and reproductive organs.

PubMed

Nisar, Nazia; Cuttriss, Abby J; Pogson, Barry J; Cazzonelli, Christopher I

2014-01-01

Cellular auxin homeostasis controls many aspects of plant growth, organogenesis and development. The existence of intracellular auxin transport mediated by endoplasmic reticulum (ER)-localized PIN5, PIN6 and PIN8 proteins is a relatively recent discovery shaping a new era in understanding auxin-mediated growth processes. Here we summarize the importance of PIN6 in mediating intracellular auxin transport during root formation, leaf vein patterning and nectary production. While, it was previously shown that PIN6 was strongly expressed in rosette leaf cell types important in vein formation, here we demonstrate by use a PIN6 promoter-reporter fusion, that PIN6 is also preferentially expressed in the vasculature of the primary root, cotyledons, cauline leaves, floral stem, sepals and the main transmitting tract of the reproductive silique. The strong, vein- specific reporter gene expression patterns enabled by the PIN6 promoter emphasizes that transcriptional control is likely to be a major regulator of PIN6 protein levels, during vasculature formation, and supports the need for ER-localized PIN proteins in selecting specialized cells for vascular function in land plants.

Expression of transcripts for fibroblast growth factor 18 and its possible receptors during postnatal dentin formation in rat molars.

PubMed

Baba, Otto; Ota, Masato S; Terashima, Tatsuo; Tabata, Makoto J; Takano, Yoshiro

2015-05-01

Fibroblast growth factors (FGFs) regulate the proliferation and differentiation of various cells via their respective receptors (FGFRs). During the early stages of tooth development in fetal mice, FGFs and FGFRs have been shown to be expressed in dental epithelia and mesenchymal cells at the initial stages of odontogenesis and to regulate cell proliferation and differentiation. However, little is known about the expression patterns of FGFs in the advanced stages of tooth development. In the present study, we focused on FGF18 expression in the rat mandibular first molar (M1) during the postnatal crown and root formation stages. FGF18 signals by RT-PCR using cDNAs from M1 were very weak at postnatal day 5 and were significantly up-regulated at days 7, 9 and 15. Transcripts were undetectable by in situ hybridization (ISH) but could be detected by in situ RT-PCR in the differentiated odontoblasts and cells of the sub-odontoblastic layer in both crown and root portions of M1 at day 15. The transcripts of FGFR2c and FGFR3, possible candidate receptors of FGF18, were detected by RT-PCR and ISH in differentiated odontoblasts throughout postnatal development. These results suggest the continual involvement of FGF18 signaling in the regulation of odontoblasts during root formation where it may contribute to dentin matrix formation and/or mineralization.

Evaluation of a platelet lysate bilayered system for periodontal regeneration in a rat intrabony three-wall periodontal defect.

PubMed

Babo, Pedro S; Cai, Xinjie; Plachokova, Adelina S; Reis, Rui L; Jansen, John; Gomes, Manuela E; Walboomers, X Frank

2018-02-01

With currently available therapies, full regeneration of lost periodontal tissues after periodontitis cannot be achieved. In this study, a combined compartmentalized system was tested, composed of (a) a platelet lysate (PL)-based construct, which was placed along the root aiming to regenerate the root cementum and periodontal ligament, and (b) a calcium phosphate cement composite incorporated with hyaluronic acid microspheres loaded with PL, aiming to promote the regeneration of alveolar bone. This bilayered system was assessed in a 3-wall periodontal defect in Wistar rats. The periodontal healing and the inflammatory response of the materials were scored for a period up to 6 weeks after implantation. Furthermore, histomorphometrical measurements were performed to assess the epithelial downgrowth, the formation of alveolar bone, and the formation of new connective tissue attachment. Our data showed that the stabilization of platelet-origin proteins on the root surface increased the overall periodontal healing score and restricted the formation of long epithelial junctions. Nevertheless, the faster degradation of the cement component with incorporated hyaluronic acid microspheres compromised the stability of the system, which hampered the periodontal regeneration. Overall, in this work, we proved the positive therapeutic effect of the immobilization of a PL-based construct over the root surface in a combined compartmentalized system to assist predictable healing of functional periodontium. Therefore, after optimization of the hard tissue analogue, the system should be further elaborated in (pre)clinical validation studies. Copyright © 2017 John Wiley & Sons, Ltd.

Inoculation with arbuscular mycorrhizal fungi suppresses initiation of haustoria in the root hemiparasite Pedicularis tricolor.

PubMed

Li, Ai-Rong; Smith, Sally E; Smith, F Andrew; Guan, Kai-Yun

2012-05-01

Plant parasitism and arbuscular mycorrhizal (AM) associations have many parallels and share a number of regulatory pathways. Despite a rapid increase in investigations addressing the roles of AM fungi in regulating interactions between parasitic plants and their hosts, few studies have tested the effect of AM fungi on the initiation and differentiation of haustoria, the parasite-specific structures exclusively responsible for host attachment and nutrient transfer. In this study, we tested the influence of AM fungi on haustorium formation in a root hemiparasitic plant. Using a facultative root hemiparasitic species (Pedicularis tricolor) with the potential to form AM associations, the effects of inoculation were tested with two AM fungal species, Glomus mosseae and Glomus intraradices, on haustorium initiation in P. tricolor grown alone or with Hordeum vulgare 'Fleet' (barley) as the host plant. This study consisted of two greenhouse pot experiments. Both AM fungal species dramatically suppressed intraspecific haustorium initiation in P. tricolor at a very low colonization level. The suppression over-rode inductive effects of the parasite's host plant on haustoria production and caused significant growth depression of P. tricolor. AM fungi had strong and direct suppressive effects on haustorium formation in the root hemiparasite. The significant role of AM fungi in haustorium initiation of parasitic plants was demonstrated for the first time. This study provides new clues for the regulation of haustorium formation and a route to development of new biocontrol strategies in management of parasitic weeds.

Assessment of Root Resorption and Root Shape by Periapical and Panoramic Radiographs: A Comparative Study.

PubMed

Ahuja, Puneeta D; Mhaske, Sheetal P; Mishra, Gaurav; Bhardwaj, Atul; Dwivedi, Ruby; Mangalekar, Sachin B

2017-06-01

One of the common findings encountered by the clinician at the end of orthodontic treatment is the apical root resorption. Root resorption occurs to various degrees. A severe form of root resorption is characterized by shortening of root for more than 4 mm or more than one-third of the total tooth length. A low incidence rate of resorption is observed based on radiographic findings for the diagnosis of root resorption, panoramic radiography, and periapical radiography. Hence, we evaluated the accuracy of panoramic radiographic films for assessing the root resorption in comparison with the periapical films. This study included the assessment of all the cases in which pre- and post-treatment radiographs were available for analysis of the assessment of the amount of root resorption. Complete records of 80 patients were analyzed. Examination of a total of 900 teeth was done. Mean age of the patients in this study was 21 years ranging from 11 to 38 years. The majority of the patients in the present study were females. All the treatments were carried out by registered experienced orthodontists having minimum experience of more than 10 years. All the cases were divided into two study groups. Group I comprised panoramic radiographic findings, while group II consisted of periapical radiographic findings. For the measurement of crown portion, root portion, and the complete root length, magnification loops of over 100 powers with parallax correction with inbuilt grids were used. Assessment of the tooth length and the crown length was done by the same observers. All the results were analyzed by Statistical Package for the Social Sciences software version 6.0. Maximum amount of root resorption was observed in case of maxillary central incisors and canines among group I and II cases respectively. However, nonsignificant difference was obtained while comparing the mean root resorption in relation to maxillary incisors and canines among the two study groups. While comparing the overall value of root resorption among the two study groups, a significant difference was obtained. The maximum value of tooth length in both the groups was observed in cases of maxillary canines. Significant differences were observed while comparing the tooth length of various teeth among the two study groups. Among the deviated forms of root shape, dilacera-tion was the most common form of root shape detected in both the study groups. Periapical radiographs are more efficient in the assessment of the shape and resorption of the root. Thorough evaluation of periapical radiographs is necessary for detection of even minute levels of root resorption.

Cerium oxide nanoparticles alter the salt stress tolerance of Brassica napus L. by modifying the formation of root apoplastic barriers.

PubMed

Rossi, Lorenzo; Zhang, Weilan; Ma, Xingmao

2017-10-01

Rapidly growing global population adds significant strains on the fresh water resources. Consequently, saline water is increasingly tapped for crop irrigation. Meanwhile, rapid advancement of nanotechnology is introducing more and more engineered nanoparticles into the environment and in agricultural soils. While some negative effects of ENPs on plant health at very high concentrations have been reported, more beneficial effects of ENPs at relatively low concentrations are increasingly noticed, opening doors for potential applications of nanotechnology in agriculture. In particular, we found that cerium oxide nanoparticles (CeO 2 NPs) improved plant photosynthesis in salt stressed plants. Due to the close connections between salt stress tolerance and the root anatomical structures, we postulated that CeO 2 NPs could modify plant root anatomy and improve plant salt stress tolerance. This study aimed at testing the hypothesis with Brassica napus in the presence of CeO 2 NPs (0, 500 mg kg -1 dry sand) and/or NaCl (0, 50 mM) in a growth chamber. Free hand sections of fresh roots were taken every seven days for three weeks and the suberin lamellae development was examined under a fluorescence microscope. The results confirmed the hypothesis that CeO 2 NPs modified the formation of the apoplastic barriers in Brassica roots. In salt stressed plants, CeO 2 NPs shortened the root apoplastic barriers which allowed more Na + transport to shoots and less accumulation of Na + in plant roots. The altered Na + fluxes and transport led to better physiological performance of Brassica and may lead to new applications of nanotechnology in agriculture. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effect of Canal Preparation with Four Different Rotary Systems on Formation of Dentinal Cracks: An In Vitro Evaluation.

PubMed

Khoshbin, Elham; Donyavi, Zakiyeh; Abbasi Atibeh, Erfan; Roshanaei, Ghodratollah; Amani, Faranak

2018-01-01

Endodontic rotary systems may result in dentinal cracks. They may propagate to vertical root fracture that compromises the outcome of endodontic treatment. This study aimed to compare Neolix and Reciproc (single-file systems), Mtwo and ProTaper (conventional rotary systems) in terms of dentinal crack formation in root canal walls. This in vitro study was conducted on 110 extracted human single-rooted teeth. The teeth were randomly divided into four experimental groups ( n =25) for root canal preparation with Neolix, Reciproc, Mtwo and ProTaper systems and two control groups ( n =5). The first control group underwent root canal instrumentation with hand files while the second control group received no preparation and was only irrigated. After instrumentation, root canals were horizontally sectioned at 3, 6 and 9 mm from the apex and inspected under a stereomicroscope under 12× magnification for detection of cracks. The data were analyzed using Chi-square, GEE test and Bonferroni tests ( P <0.05). No crack was found in the control groups. All rotary systems caused dentinal cracks. ProTaper, Reciproc, Mtwo and Neolix caused cracks in 92%, 80%, 68% and 48% of samples. ProTaper caused significantly more cracks than Neolix and Mtwo ( P <0.05). No significant differences were noted between other groups ( P >0.05). All rotary systems cause dentinal cracks and it is significantly different in apical, middle and coronal third of the root. Neolix appears to be a suitable alternative to other rotary systems since use of this single-file system saves time and cost and minimizes trauma to dentinal walls.

The Effect of Canal Preparation with Four Different Rotary Systems on Formation of Dentinal Cracks: An In Vitro Evaluation

PubMed Central

Khoshbin, Elham; Donyavi, Zakiyeh; Abbasi Atibeh, Erfan; Roshanaei, Ghodratollah; Amani, Faranak

2018-01-01

Introduction: Endodontic rotary systems may result in dentinal cracks. They may propagate to vertical root fracture that compromises the outcome of endodontic treatment. This study aimed to compare Neolix and Reciproc (single-file systems), Mtwo and ProTaper (conventional rotary systems) in terms of dentinal crack formation in root canal walls. Methods and Materials: This in vitro study was conducted on 110 extracted human single-rooted teeth. The teeth were randomly divided into four experimental groups (n=25) for root canal preparation with Neolix, Reciproc, Mtwo and ProTaper systems and two control groups (n=5). The first control group underwent root canal instrumentation with hand files while the second control group received no preparation and was only irrigated. After instrumentation, root canals were horizontally sectioned at 3, 6 and 9 mm from the apex and inspected under a stereomicroscope under 12× magnification for detection of cracks. The data were analyzed using Chi-square, GEE test and Bonferroni tests (P<0.05). Results: No crack was found in the control groups. All rotary systems caused dentinal cracks. ProTaper, Reciproc, Mtwo and Neolix caused cracks in 92%, 80%, 68% and 48% of samples. ProTaper caused significantly more cracks than Neolix and Mtwo (P<0.05). No significant differences were noted between other groups (P>0.05). Conclusion: All rotary systems cause dentinal cracks and it is significantly different in apical, middle and coronal third of the root. Neolix appears to be a suitable alternative to other rotary systems since use of this single-file system saves time and cost and minimizes trauma to dentinal walls. PMID:29707009

Reinterpreting individualism and collectivism. Their religious roots and monologic versus dialogic person-other relationship.

PubMed

Sampson, E E

2000-12-01

Examining the religious roots of individualism and collectivism and seeing them as defining alternative conceptions of the person-other relationship reveal a close link between Christianity and the former and between rabbinic Judaism and the latter. Comparisons between these 2 religious formations in the Western world expose a relationship between Christian individualism and an instrumental and monologic understanding of the person-other relationship and a contrasting rabbinic view that offers a formative and dialogic understanding of that relationship. Because the Christian view has been dominant, its understandings have framed the debates on individualism-collectivism and defined the options available for the person-other relationship, providing a somewhat distorted picture of the possibilities for humankind. The dialogic and formative perspective of the rabbinic tradition introduces an alternative portrait of human nature.

Orthodontic treatment in patient with idiopathic root resorption: a case report.

PubMed

Rey, Diego; Smit, Rosana Martínez; Gamboa, Liliana

2015-01-01

Multiple idiopathic external root resorption is a rare pathological condition usually detected as an incidental radiographic finding. External root resorption of permanent teeth is a multifactorial process related to several local and systemic factors. If an etiological factor cannot be identified for root resorption, the term "idiopathic" is applied. This report presents a case of multiple idiopathic apical root resorption. The condition was found in a young female patient seeking orthodontic treatment due to malocclusion. This kind of resorption starts apically and progresses coronally, causing a gradual shortening and rounding of the remaining root. Patients with this condition are not the ideal candidates for orthodontic treatment; however, the aim of this report is to describe an unusual case of idiopathic root resorption involving the entire dentition, and to present the orthodontic treatment of this patient. It describes the progress and completion of orthodontic therapy with satisfactory end results.

Isolation, characterization and expression analysis of the BABY BOOM (BBM) gene from Larix kaempferi × L. olgensis during adventitious rooting.

PubMed

Li, Kui-Peng; Sun, Xiao-Mei; Han, Hua; Zhang, Shou-Gong

2014-11-10

The full-length cDNA and genomic sequences of the BABY BOOM (BBM) gene, designated LkBBM, were isolated from Larix kaempferi × Larix olgensis. The 3324 bp cDNA was cloned and its open reading frame (ORF) consists of 2370 nucleotides. The deduced 789 amino acid protein contains two AP2 domains and a BBM specific motif. Four conserved motifs between BBM and PLT were identified, which may be conducive to the similar function of BBM and PLT. The three dimensional (3D) structure of LkBBM was predicted and β-sheets in the AP2-R2 domain of LkBBM might recognize the specific base pairs in the major groove. Analysis of the LkBBM gene structure indicates that the gene has eight introns and nine exons. In the 5'-flanking promoter region of LkBBM, many important potential cis-acting elements were identified, such as the TATABOX5 element (a functional TATA element), ROOTMOTIFTAPOX1 element (element of root specificity), AUXREPSIAA4 element (element involved in auxin responsiveness and gene expression in root meristem), MYB1AT element (element involved in MYB recognition), ARR1AT element (element involved in cytokinin responsiveness), GARE1OSREP1 element (element involved in gibberellin responsiveness) and PYRIMIDINEBOXHVEPB1 element (element involved in abscisic acid responsiveness), which all suggested that the expression of LkBBM is highly regulated. Compared with gene expression levels in the stem, stem tip and leaf, LkBBM shows a specific expression in the root, which indicates that LkBBM plays a key role in regulating the development and growth of root in larch. In the processing of larch adventitious root formation, LkBBM started to express on the eighth day after rooting treatment and its transcript level increased continuously afterwards. According to the gene characteristics, LkBBM is proposed as a molecular marker for root primordia of larch, and the initial period of LkBBM expression may be the formation period of root primordia in the processing of adventitious rooting of larch. Copyright © 2014 Elsevier B.V. All rights reserved.

Fine Root Abundance and Dynamics of Stone Pine (Pinus cembra) at the Alpine Treeline Is Not Impaired by Self-shading

PubMed Central

Kubisch, Petra; Leuschner, Christoph; Coners, Heinz; Gruber, Andreas; Hertel, Dietrich

2017-01-01

Low temperatures are crucial for the formation of the alpine treeline worldwide. Since soil temperature in the shade of tree canopies is lower than in open sites, it was assumed that self-shading may impair the trees’ root growth performance. While experiments with tree saplings demonstrate root growth impairment at soil temperatures below 5–7°C, field studies exploring the soil temperature – root growth relationship at the treeline are missing. We recorded soil temperature and fine root abundance and dynamics in shaded and sun-exposed areas under canopies of isolated Pinus cembra trees at the alpine treeline. In contrast to the mentioned assumption, we found more fine root biomass and higher fine root growth in colder than in warmer soil areas. Moreover, colder areas showed higher fine root turnover and thus lower root lifespan than warmer places. We conclude that P. cembra balances enhanced fine root mortality in cold soils with higher fine root activity and by maintaining higher fine root biomass, most likely as a response to shortage in soil resource supply. The results from our study highlight the importance of in situ measurements on mature trees to understand the fine root response and carbon allocation pattern to the thermal growth conditions at the alpine treeline. PMID:28469633

The Dynamics of Sediment Oxygenation in Marsh Rhizospheres

NASA Astrophysics Data System (ADS)

Koop-Jakobsen, K.

2014-12-01

Many marsh grasses are capable of internal oxygen transport from aboveground sources to belowground roots and rhizomes, where oxygen may leak across the rhizodermis and oxygenate the surrounding sediment. In the field, the extent of sediment oxygenation in marshes was assessed in the rhizosphere of the marsh grass; Spartina anglica, inserting 70 optical fiber oxygen sensors into the rhizosphere. Two locations with S. anglica growing in different sediment types were investigated. No oxygen was detected in the rhizospheres indicating that belowground sediment oxygenation in S. anglica has a limited effect on the bulk anoxic sediment and is restricted to sediment in the immediate vicinity of the roots. In the laboratory, the presence of 1.5mm wide and 16mm long oxic root zones was demonstrated around root tips of S. anglica growing in permeable sandy sediment using planar optodes recording 2D-images of the oxygen distribution. Oxic root zones in S. anglica growing in tidal flat deposits were significantly smaller. The size of oxic roots zones was highly dynamic and affected by tidal inundations as well as light availability. Atmospheric air was the primary oxygen source for belowground sediment oxygenation, whereas photosynthetic oxygen production only played a minor role for the size of the oxic root zones during air-exposure of the aboveground biomass. During tidal inundations (1.5 h) completely submerging the aboveground biomass cutting off access to atmospheric oxygen, the size of oxic root zones were reduced significantly in the light and oxic root zones were completely eliminated in darkness. Sediment oxygenation in the rhizospheres of marsh grasses is of significant importance for marshes ability to retain inorganic nitrogen before it reaches the coastal waters. The presence of oxic roots zones promotes coupled nitrification-denitrification at depth in the sediment, which can account for more than 80% of the total denitrification in marshes.

A new mechanism for calcium loss in forest-floor soils

Treesearch

Gregory B. Lawrence; Mark B. David; Walter C. Shortle

1995-01-01

Calcium is the fifth most abundant element in trees, and is an essential component for wood formation and the maintenance of cell walls. Depletion of Ca from the rooting zone can result in acidification of soil and surface water and possibly growth decline and dieback of red spruce. During the past six decades, concentrations of root-available Ca (exchangeable and acid...

Antibiofilm activity of Vetiveria zizanioides root extract against methicillin-resistant Staphylococcus aureus.

PubMed

Kannappan, Arunachalam; Gowrishankar, Shanmugaraj; Srinivasan, Ramanathan; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

2017-09-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading human pathogen responsible for causing chronic clinical manifestation worldwide. In addition to antibiotic resistance genes viz. mecA and vanA, biofilm formation plays a prominent role in the pathogenicity of S. aureus by enhancing its resistance to existing antibiotics. Considering the role of folk medicinal plants in the betterment of human health from the waves of multidrug resistant bacterial infections, the present study was intended to explore the effect of Vetiveria zizanioides root on the biofilm formation of MRSA and its clinical counterparts. V. zizanioides root extract (VREX) showed a concentration-dependent reduction in biofilm formation without hampering the cellular viability of the tested strains. Micrographs of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) portrayed the devastating impact of VREX on biofilm formation. In addition to antibiofilm activity, VREX suppresses the production of biofilm related phenotypes such as exopolysaccharide, slime and α-hemolysin toxin. Furthermore, variation in FT-IR spectra evidenced the difference in cellular factors of untreated and VREX treated samples. Result of mature biofilm disruption assay and down regulation of genes like fnbA, fnbB, clfA suggested that VREX targets these adhesin genes responsible for initial adherence. GC-MS analysis revealed the presence of sesquiterpenes as a major constituent in VREX. Thus, the data of present study strengthen the ethnobotanical value of V. zizanioides and concludes that VREX contain bioactive molecules that have beneficial effect over the biofilm formation of MRSA and its clinical isolates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Intermediate Flush Using Different Devices to Prevent Chemical Smear Layer Formation.

PubMed

Silva, Camilla Corrêa; Ferreira, Vivian Maria Durange; De-Deus, Gustavo; Herrera, Daniel Rodrigo; Prado, Maíra do; Silva, Emmanuel João Nogueira Leal da

2017-01-01

This study compared the effect of intermediate flush with distilled water delivered by conventional irrigation, EndoVac microcannula or Self-Adjusting File (SAF) system in the prevention of chemical smear layer (CSL) formation. Thirty human premolars were used. Canals were prepared with Reciproc system and 5.25% NaOCl. After chemomechanical preparation, samples were divided in 3 groups (n=10) according to the intermediate irrigation protocol with distilled water using: conventional irrigation, EndoVac microcannula or SAF. A final flush with 2% chlorhexidine solution was used and scanning electron microscopy was performed to assess protocol effectiveness. Two calibrated evaluators attributed scores according the presence or absence of CSL on the surface of the root canal walls at the coronal, middle and apical thirds, as follows: (1) no CSL; (2) small amounts of CSL; (3) moderate CSL; and (4) heavy CSL. Differences between protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. SAF resulted in less formation of CSL when compared with the conventional irrigation and EndoVac microcannula (p<0.05). When root canal thirds were analyzed, conventional irrigation and EndoVac groups showed less CSL formation at coronal and middle thirds in comparison to the apical third (p<0.05). In SAF group, there was no difference among the thirds (p>0.05). It may be concluded that an intermediate flush of distilled water, delivered by the SAF system resulted in a better reduction of CSL formation during chemomechanical preparation.

Bonding durability of dual-curing composite core material with different self-etching adhesive systems in a model complete vertical root fracture reconstruction.

PubMed

Waidyasekera, Kanchana; Nikaido, Toru; Weerasinghe, Dinesh; Nurrohman, Hamid; Tagami, Junji

2012-04-01

This study evaluated a dual-curing composite along with different dentin adhesive systems for 1 year under water storage, as a new bonding method of root fragments in complete vertical root fracture. Bovine root fragments were bonded with the dual-curing resin composite Clearfil DC Core Automix (DCA) and one of three adhesive systems: two-step self-etching adhesive Clearfil SE Bond (SE), one-step self-etching adhesive Tokuyama Bond Force (BF), one-step dual-curing self-etching adhesive Clearfil DC Bond (DC). Microtensile bond strength (µTBS)/ultimate tensile bond strength (UTS), FE-SEM ultramorphology of fracture modes, and adhesive dentin interface were observed after water storage for periods of up to one year. The data were analyzed with two-way ANOVA. µTBS was influenced by "dentin adhesive system" (F = 324.455, p < 0.001) and "length of water storage" (F = 8.470, p < 0.001). SE yielded significantly higher µTBS, regardless of storage period (p < 0.05) and maintained the initial µTBS without a significant change after 1 year of water storage (p > 0.05). From 24 h to 1 month, BF showed significantly higher bond strength than DC. UTS of DCA was influenced only by the curing mode of the material (F = 5.051, p = 0.027), but not by the length of water storage (F = 0.053, p > 0.05). Two-step self-etching adhesive systems and dual-curing composite core material can be considered as a suitable bonding method for complete root fractures.

Full-mouth treatment of gingival recessions and noncarious cervical lesions with coronally advanced flap and xenogeneic collagen matrix: 
a 2-year case report.

PubMed

Martiniello, Nello; Stefanini, Martina; Zucchelli, Giovanni

In clinical practice it is common to observe adjacent multiple gingival recessions (MGRs) associated with noncarious cervical lesions (NCCLs). The aim of this 2-year case report was to describe the full-mouth treatment of a patient affected by MGRs and NCCLs, with a combined restorative-surgical approach using a coronally advanced flap (CAF) and a xenogeneic collagen matrix (CM). Before surgery, a composite restoration filled the deepest portion of the NCCL defects and was finished at the level of the maximum root coverage (MRC). The surgical technique adopted for the root coverage procedures was CAF for MGRs without vertical releasing incisions in the maxilla, and with one vertical releasing incision in the mandible. The CM was positioned at the level of the cementoenamel junction (CEJ), and sutured at the base of the anatomic de-epithelialized papillae. The flap was shifted coronally, providing complete coverage of the CM, and sutured coronal to the CEJ with a variable number of sling sutures. At 2 years, complete root coverage was achieved in all treated sites, and the patient reported complete resolution of dental hypersensitivity. In the questionnaire, the patient-reported outcome showed a high level of esthetic satisfaction (mean score: 9.6; range: 9 to 10), and the objective esthetic evaluation with the root coverage esthetic score (RES) system showed a very high result (mean: 9.4). The suggested combined restorative-surgical approach provided successful root coverage and a favorable esthetic outcome in the treatment of MGR associated with NCCLs.

Ontogeny of plants under various gravity condition

NASA Astrophysics Data System (ADS)

Laurinavičius, R.; Švegždienṡ, D.; Raklevičienė, D.; Kenstavičienė, P.

2001-01-01

The results of experiments performed under conditions of microgravity (MG) or under its simulation on the horizontal clinostat (HC) with the callus, seedlings of various species and embryogenic structures have revealed a definite role of gravity as an ecological factor in the processes of cytomorphogenesis, growth, and development. The transformation of differentiated somatic cells of arabidopsis seed into undifferentiated callus was not inhibited under MG, though modifications of the whole callus morphology and of mean cell and nucleus size were observed. The morphogenesis of polar structures such as root-hair bearing cells of Lactuca primary root has been shown to be modified in the course of differentiation under mass acceleration diminished below 0.1 g. Seed germination and seedling morphogenesis under MG follow their normal course, but a significant stimulation of shoot growth with no effect on primary root growth has been determined. A successful in vitro regeneration of Nicotiana tabacum plantlets from leaf cells and subsequent formation of shoots and roots on a continuously rotating HC as well as the formation of viable seeds during seed-to-seed growth of Arabidopsis plants under MG have indicated that gravity plays but a limited role in the processes of embryogenesis and organogenesis.

Foliar application of pyraclostrobin fungicide enhances the growth, rhizobial-nodule formation and nitrogenase activity in soybean (var. JS-335).

PubMed

Joshi, Juhie; Sharma, Sonika; Guruprasad, K N

2014-09-01

A field study was conducted to investigate the impact of the fungicide pyraclostrobin (F500 - Headline®; a.i. 20%) on the activity of nitrogenase in soybean (var. JS-335). Pyraclostrobin (F500) was applied on the leaves of soybean plants at 10 and 20 days after emergence (DAE) of seedlings at concentrations ranging from 0.05% to 1%. Leghemoglobin (Lb) content and nitrogenase activity in root nodules were analyzed at 45(th)day after emergence of seedlings indicated a remarkable increase in Lb content and enhanced activity of nitrogenase in the root nodules of pyraclostrobin treated plants. The fungicide also enhanced the number of nodules along with weight of nodules, root biomass and growth of shoot and leaves. Enhanced nitrogen fixation in the root nodules by pyraclostrobin improves the growth of the plant in soybean before flowering and pod formation which ultimately resulted in yield and yield attributes. These results suggest that pyraclostrobin (F500) can be successfully employed as a foliar spray under field conditions to enhance the growth, nitrogen assimilation and hence yield of soybean. Copyright © 2014 Elsevier Inc. All rights reserved.

Influence of sulfur on the accumulation of mercury in rice plant (Oryza sativa L.) growing in mercury contaminated soils.

PubMed

Li, Yunyun; Zhao, Jiating; Guo, Jingxia; Liu, Mengjiao; Xu, Qinlei; Li, Hong; Li, Yu-Feng; Zheng, Lei; Zhang, Zhiyong; Gao, Yuxi

2017-09-01

Sulfur (S) is an essential element for plant growth and its biogeochemical cycling is strongly linked to the species of heavy metals in soil. In this work, the effects of S (sulfate and elemental sulfur) treatment on the accumulation, distribution and chemical forms of Hg in rice growing in Hg contaminated soil were investigated. It was found that S could promote the formation of iron plaque on the root surface and decrease total mercury (T-Hg) and methylmercury (MeHg) accumulation in rice grains, straw, and roots. Hg in the root was dominated in the form of RS-Hg-SR. Sulfate treatment increased the percentage of RS-Hg-SR to T-Hg in the rice root and changed the Hg species in soil. The dominant Hg species (70%) in soil was organic substance bound fractions. Sulfur treatment decreased Hg motility in the rhizosphere soils by promoting the conversion of RS-Hg-SR to HgS. This study is significant since it suggests that low dose sulfur treatment in Hg-containing water irrigated soil can decrease both T-Hg and MeHg accumulation in rice via inactivating Hg in the soil and promoting the formation of iron plaque in rice root, which may reduce health risk for people consuming those crops. Copyright © 2017. Published by Elsevier Ltd.

The Role of Smoking and Gingival Crevicular Fluid Markers on Coronally Advanced Flap Outcomes

PubMed Central

Kaval, Başak; Renaud, Diane E.; Scott, David A.; Buduneli, Nurcan

2015-01-01

Background This study evaluates possible effects of smoking on the following: 1) biochemical content in gingival crevicular fluid (GCF) samples from sites of gingival recession and saliva; and 2) clinical outcomes of coronally advanced flap (CAF) for root coverage. Methods Eighteen defects in 15 patients were included in each of the smoker and non-smoker groups. Baseline cotinine, basic fibroblast growth factor, vascular endothelial growth factor, platelet-derived growth factor, interleukin (IL)-8, IL-10, IL-12, tumor necrosis factor-α, matrix metalloproteinase (MMP)-8, MMP-9, and plasminogen activator inhibitor-1 levels were determined in GCF and saliva samples. CAF with microsurgery technique was applied. Plaque index, papilla bleeding index, recession depth (RD), recession width (RW), and root surface area were evaluated at baseline and postoperative months 1, 3, and 6. Probing depth, clinical attachment level (CAL), and keratinized gingival width (KGW) was recorded at baseline and month 6. Percentage of root coverage and complete root coverage were calculated at postoperative months 1, 3, and 6. Results All biochemical parameters were similar in the two groups apart from the definite difference in salivary cotinine concentrations (P = 0.000). Compared with the baseline values, RD, RW, CAL, and root surface area decreased, and KGW increased, with no significant difference between the study groups. CAL gain, percentage of root coverage, and complete root-coverage rates were similar in the study groups. Conclusion Similar baseline biochemical data and comparably high success rates of root coverage with CAF in systemically and periodontally healthy smokers versus non-smokers suggest lack of adverse effects of smoking on clinical outcomes. PMID:23725027

Second-look arthroscopic assessment and clinical results of modified pull-out suture for posterior root tear of the medial meniscus.

PubMed

Cho, Jin-Ho; Song, Jae-Gwang

2014-06-01

To identify the structural integrity of the healing site after arthroscopic repair of a posterior root tear of the medial meniscus by second-look arthroscopy and to determine the clinical relevance of the findings. From January 2005 to December 2010, 20 consecutive patients underwent arthroscopic modified pull-out suture repair for a posterior root tear of the medial meniscus. Thirteen patients were available for second-look arthroscopic evaluation. The healing status of the medial meniscus was classified as complete healing, lax healing, scar tissue healing, and failed healing. We evaluated the correlation between the clinical symptoms and second-look arthroscopic findings. Clinical evaluation was based on the Lysholm knee scores and Hospital for Special Surgery (HSS) scores. There were 4 cases of complete healing, 4 lax healing, 4 scar tissue healing, and 1 failed healing. The healing status of the repaired meniscus appeared to be related to the clinical symptoms. Patients who achieved complete tissue healing had no complaint. The healing status exhibited no relationship with age, mechanical axis, degree of subluxation, and symptom duration. The mean Lysholm score improved from 34.7 preoperatively to 75.6 at follow-up and the mean HSS score also significantly increased from 33.5 to 82.2. We achieved 4 complete and 8 partial healing (lax or scar) of the medial meniscus in this retrospective case series of posterior horn meniscus root repairs performed by 1 surgeon. Further research is needed to clarify why all patients showed clinical improvement despite findings of partial healing on second-look arthroscopy.

Autonomic straightening after gravitropic curvature of cress roots

NASA Technical Reports Server (NTRS)

Stankovic, B.; Volkmann, D.; Sack, F. D.

1998-01-01

Few studies have documented the response of gravitropically curved organs to a withdrawal of a constant gravitational stimulus. The effects of stimulus withdrawal on gravitropic curvature were studied by following individual roots of cress (Lepidium sativum L.) through reorientation and clinostat rotation. Roots turned to the horizontal curved down 62 degrees and 88 degrees after 1 and 5 h, respectively. Subsequent rotation on a clinostat for 6 h resulted in root straightening through a loss of gravitropic curvature in older regions and through new growth becoming aligned closer to the prestimulus vertical. However, these roots did not return completely to the prestimulus vertical, indicating the retention of some gravitropic response. Clinostat rotation shifted the mean root angle -36 degrees closer to the prestimulus vertical, regardless of the duration of prior horizontal stimulation. Control roots (no horizontal stimulation) were slanted at various angles after clinostat rotation. These findings indicate that gravitropic curvature is not necessarily permanent, and that the root retains some commitment to its equilibrium orientation prior to gravitropic stimulation.

Bringing life to soil physical processes

NASA Astrophysics Data System (ADS)

Hallett, P. D.

2013-12-01

When Oklahoma's native prairie grass roots were replaced by corn, the greatest environmental (and social) disaster ever to hit America ensued. The soils lost structure, physical binding by roots was annihilated and when drought came the Great Dust Bowl commenced. This form of environmental disaster has repeated over history and although not always apparent, similar processes drive the degradation of seemingly productive farmland and forests. But just as negative impacts on biology are deleterious to soil physical properties, positive impacts could reverse these trends. In finding solutions to soil sustainability and food security, we should be able to exploit biological processes to improve soil physical properties. This talk will focus on a quantitative understanding of how biology changes soil physical behaviour. Like the Great Dust Bowl, it starts with reinforcement mechanisms by plant roots. We found that binding of soil by cereal (barley) roots within 5 weeks of planting can more than double soil shear strength, with greater plant density causing greater reinforcement. With time, however, the relative impact of root reinforcement diminishes due to root turnover and aging of the seedbed. From mechanical tests of individual roots, reasonable predictions of reinforcement by tree roots are possible with fibre bundle models. With herbaceous plants like cereals, however, the same parameters (root strength, stiffness, size and distribution) result in a poor prediction. We found that root type, root age and abiotic factors such as compaction and waterlogging affect mechanical behaviour, further complicating the understanding and prediction of root reinforcement. For soil physical stability, the interface between root and soil is an extremely important zone in terms of resistance of roots to pull-out and rhizosphere formation. Compounds analogous to root exudates have been found with rheological tests to initially decrease the shear stress where wet soils flow, but after decomposition of these exudates by microbes the shear stress increases. This suggests an initial dispersion, followed by aggregation of the soil, which explains the structural arrangement of soil particles in the rhizosphere observed by microscopy. Dispersion of soil minerals in the root zone is important to release bound nutrients from mineral surfaces. Using fracture mechanics we measured large impacts of biological exudates on the toughness and interparticle bond energy of soils. Now novel tests are being developed to quantify interparticle bonding by biological exudates on single and multiple particle contacts, including mechanical test specimens that can be inoculated with specific bacteria or fungi. This will allow for clay mineralogy, water potential and solution chemistry impacts on interparticle bonding to be quantified directly. Wettability experiments with the same samples measure hydrological properties such as contact angle. Basic information from these tests will help explain biological processes that drive soil structure formation and stabilisation, providing data for models of soil structure dynamics.

Simulation of root forms using cellular automata model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winarno, Nanang, E-mail: nanang-winarno@upi.edu; Prima, Eka Cahya; Afifah, Ratih Mega Ayu

This research aims to produce a simulation program for root forms using cellular automata model. Stephen Wolfram in his book entitled “A New Kind of Science” discusses the formation rules based on the statistical analysis. In accordance with Stephen Wolfram’s investigation, the research will develop a basic idea of computer program using Delphi 7 programming language. To best of our knowledge, there is no previous research developing a simulation describing root forms using the cellular automata model compared to the natural root form with the presence of stone addition as the disturbance. The result shows that (1) the simulation usedmore » four rules comparing results of the program towards the natural photographs and each rule had shown different root forms; (2) the stone disturbances prevent the root growth and the multiplication of root forms had been successfully modeled. Therefore, this research had added some stones, which have size of 120 cells placed randomly in the soil. Like in nature, stones cannot be penetrated by plant roots. The result showed that it is very likely to further develop the program of simulating root forms by 50 variations.« less

Cyclic GMP is involved in auxin signalling during Arabidopsis root growth and development.

PubMed

Nan, Wenbin; Wang, Xiaomin; Yang, Lei; Hu, Yanfeng; Wei, Yuantao; Liang, Xiaolei; Mao, Lina; Bi, Yurong

2014-04-01

The second messenger cyclic guanosine 3',5'-monophosphate (cGMP) plays an important role in plant development and responses to stress. Recent studies indicated that cGMP is a secondary signal generated in response to auxin stimulation. cGMP also mediates auxin-induced adventitious root formation in mung bean and gravitropic bending in soybean. Nonetheless, the mechanism of the participation of cGMP in auxin signalling to affect these growth and developmental processes is largely unknown. In this report we provide evidence that indole-3-acetic acid (IAA) induces cGMP accumulation in Arabidopsis roots through modulation of the guanylate cyclase activity. Application of 8-bromo-cGMP (a cell-permeable cGMP derivative) increases auxin-dependent lateral root formation, root hair development, primary root growth, and gene expression. In contrast, inhibitors of endogenous cGMP synthesis block these processes induced by auxin. Data also showed that 8-bromo-cGMP enhances auxin-induced degradation of Aux/IAA protein modulated by the SCF(TIR1) ubiquitin-proteasome pathway. Furthermore, it was found that 8-bromo-cGMP is unable to directly influence the auxin-dependent TIR1-Aux/IAA interaction as evidenced by pull-down and yeast two-hybrid assays. In addition, we provide evidence for cGMP-mediated modulation of auxin signalling through cGMP-dependent protein kinase (PKG). Our results suggest that cGMP acts as a mediator to participate in auxin signalling and may govern this process by PKG activity via its influence on auxin-regulated gene expression and auxin/IAA degradation.

Effect of Different Torque Settings on Crack Formation in Root Dentin.

PubMed

Dane, Asım; Capar, Ismail Davut; Arslan, Hakan; Akçay, Merve; Uysal, Banu

2016-02-01

The aim of the present study was to observe the incidence of cracks in root canal dentin using the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland) at low- and high-torque settings. Sixty-nine mandibular premolar teeth that had been extracted for different reasons were selected. The teeth were divided into 3 groups: an unprepared control group, a low-torque settings group (SX = 3, S1 = 2, S2 = 1, F1 = 1.5, F2 = 2, F3 = 2, F4 = 2 N/cm), and a high-torque settings group (SX = 4, S1 = 4, S2 = 1.5, F1 = 2, F2 = 3, F3 = 3, F4 = 3 N/cm). After a root canal procedure, all the teeth were horizontally sectioned at 2, 4, 6, and 8 mm from the apex. Then, under a stereomicroscope, all the slices were examined to determine the presence of cracks. A chi-square test was used for data analysis. The significance level was set at P = .05. There were no cracks in the unprepared control group. Vertical root fractures were not observed in any of the groups. There were significantly fewer cracks (17.4% of the sections) in the low-torque group than in the high-torque group (29.4% of the sections) (P < .05). In this in vitro study, the instrumentation of root canals with the ProTaper Universal instrument caused more crack formation in root canal dentin at high-torque than at low-torque settings. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Alleviation of Al Toxicity by Si Is Associated with the Formation of Al-Si Complexes in Root Tissues of Sorghum.

PubMed

Kopittke, Peter M; Gianoncelli, Alessandra; Kourousias, George; Green, Kathryn; McKenna, Brigid A

2017-01-01

Silicon is reported to reduce the toxic effects of Al on root elongation but the in planta mechanism by which this occurs remains unclear. Using seedlings of soybean ( Glycine max ) and sorghum ( Sorghum bicolor ), we examined the effect of up to 2 mM Si on root elongation rate (RER) in Al-toxic nutrient solutions. Synchrotron-based low energy X-ray fluorescence (LEXRF) was then used for the in situ examination of the distribution of Al and Si within cross-sections cut from the apical tissues of sorghum roots. The addition of Si potentially increased RER in Al-toxic solutions, with RER being up to ca. 0.3 mm h -1 (14%) higher for soybean and ca. 0.2 mm h -1 (17%) higher for sorghum relative to solutions without added Si. This improvement in RER could not be attributed to a change in Al-chemistry of the bulk nutrient solution, nor was it due to a change in the concentration of Al within the apical (0-10 mm) root tissues. Using LEXRF to examine sorghum, it was demonstrated that in roots exposed to both Al and Si, much of the Al was co-located with Si in the mucigel and outer apoplast. These observations suggest that Si reduces the toxicity of Al in planta through formation of Al-Si complexes in mucigel and outer cellular tissues, thereby decreasing the binding of Al to the cell wall where it is known to inhibit wall loosening as required for cell elongation.

Relevance of the clustered regularly interspaced short palindromic repeats of Enterococcus faecalis strains isolated from retreatment root canals on periapical lesions, resistance to irrigants and biofilms

PubMed Central

Tong, Zhongchun; Du, Yu; Ling, Junqi; Huang, Lijia; Ma, Jinglei

2017-01-01

A high prevalence of Enterococcus faecalis (E. faecalis) is observed in teeth with root canal treatment failures. Clustered regularly interspaced short palindromic repeats (CRISPR) are widely distributed in prokaryotes that have adaptive immune systems against mobile elements, including pathogenic genes. The present study investigated the relevance of the CRISPR in E. faecalis strains isolated from retreated root canals on biofilms, periapical lesions and drug resistance. A total of 20 E. faecalis strains were extracted from the root canals of teeth referred for root canal retreatment. CRISPR-Cas loci were identified by two pairs of relevant primers and polymerase chain reaction. The susceptibility of the 20 isolated strains to intracanal irrigants was evaluated by 1- and 5-minute challenges with a mixture of a tetracycline isomer, an acid and a detergent (MTAD), 2% chlorhexidine (CHX) and 5.25% sodium hypochlorite (NaOCl). The microtiter plate assay and crystal violet staining were used to compare the biofilm formation of the E. faecalis isolate strains. Out of the 20 E. faecalis isolate strains, 5 strains that lacked CRISPR-cas determinants exhibited significant periapical lesions. Among the 15 strains containing CRISPR-cas determinants, 8 were isolated from root canals with inadequate fillings and 7 were isolated from root canals without any fillings. The five strains lacking CRISPR-cas loci were observed to be more resistant to MTAD and 2% CHX than the 15 strains that had CRISPR-cas loci. All of the strains exhibited the same susceptibility to 5.25% NaOCl. Furthermore, the 5 strains lacking CRISPR-cas determinants generated more biofilm than the other 15 strains. Thus, the results of the present study suggested that E. faecalis root canal isolates lacking CRISPR-cas exhibit higher resistance to intracanal irrigants, stronger biofilm formation and generate significant periapical lesions. PMID:29285081

Relevance of the clustered regularly interspaced short palindromic repeats of Enterococcus faecalis strains isolated from retreatment root canals on periapical lesions, resistance to irrigants and biofilms.

PubMed

Tong, Zhongchun; Du, Yu; Ling, Junqi; Huang, Lijia; Ma, Jinglei

2017-12-01

A high prevalence of Enterococcus faecalis ( E. faecalis ) is observed in teeth with root canal treatment failures. Clustered regularly interspaced short palindromic repeats (CRISPR) are widely distributed in prokaryotes that have adaptive immune systems against mobile elements, including pathogenic genes. The present study investigated the relevance of the CRISPR in E. faecalis strains isolated from retreated root canals on biofilms, periapical lesions and drug resistance. A total of 20 E. faecalis strains were extracted from the root canals of teeth referred for root canal retreatment. CRISPR-Cas loci were identified by two pairs of relevant primers and polymerase chain reaction. The susceptibility of the 20 isolated strains to intracanal irrigants was evaluated by 1- and 5-minute challenges with a mixture of a tetracycline isomer, an acid and a detergent (MTAD), 2% chlorhexidine (CHX) and 5.25% sodium hypochlorite (NaOCl). The microtiter plate assay and crystal violet staining were used to compare the biofilm formation of the E. faecalis isolate strains. Out of the 20 E. faecalis isolate strains, 5 strains that lacked CRISPR-cas determinants exhibited significant periapical lesions. Among the 15 strains containing CRISPR-cas determinants, 8 were isolated from root canals with inadequate fillings and 7 were isolated from root canals without any fillings. The five strains lacking CRISPR-cas loci were observed to be more resistant to MTAD and 2% CHX than the 15 strains that had CRISPR-cas loci. All of the strains exhibited the same susceptibility to 5.25% NaOCl. Furthermore, the 5 strains lacking CRISPR-cas determinants generated more biofilm than the other 15 strains. Thus, the results of the present study suggested that E. faecalis root canal isolates lacking CRISPR-cas exhibit higher resistance to intracanal irrigants, stronger biofilm formation and generate significant periapical lesions.

Revascularization and Apical Plug in an Immature Molar

PubMed Central

Roghanizadeh, Leyla; Fazlyab, Mahta

2018-01-01

Managing of necrotic permanent teeth with immature apices is a treatment challenges. Treatment of such teeth includes apexification, apical plug and more recently, revascularization technique with the probable advantage of continuation of root development. In the present case report the referred patient had discomfort with a necrotic immature mandibular first molar. Periapical radiography showed a rather large apical lesion around immature roots. Revascularization protocol using calcium-enriched mixture (CEM) cement was indicated for the mesial root. However, in distal canal apical plug technique was applied. At 2-year follow-up, both procedures were successful in relieving patient’s symptoms. Dentin formation and increase in length of the mesial root was obvious. Apical plug and revascularization technique proved to be successful in management of necrotic immature teeth; moreover, revascularization carried the advantage of continuation of root development. PMID:29692851

Quantitation of Cellular Dynamics in Growing Arabidopsis Roots with Light Sheet Microscopy

PubMed Central

Birnbaum, Kenneth D.; Leibler, Stanislas

2011-01-01

To understand dynamic developmental processes, living tissues have to be imaged frequently and for extended periods of time. Root development is extensively studied at cellular resolution to understand basic mechanisms underlying pattern formation and maintenance in plants. Unfortunately, ensuring continuous specimen access, while preserving physiological conditions and preventing photo-damage, poses major barriers to measurements of cellular dynamics in growing organs such as plant roots. We present a system that integrates optical sectioning through light sheet fluorescence microscopy with hydroponic culture that enables us to image, at cellular resolution, a vertically growing Arabidopsis root every few minutes and for several consecutive days. We describe novel automated routines to track the root tip as it grows, to track cellular nuclei and to identify cell divisions. We demonstrate the system's capabilities by collecting data on divisions and nuclear dynamics. PMID:21731697

Root resection under the surgical field employed for extraction of impacted tooth and management of external resorption.

PubMed

Pai, Ar Vivekananda; Khosla, Manak

2012-07-01

This case report illustrates determination of prognosis and immediate resection carried out, before completing the endodontic therapy, during the surgery employed for managing a nonperiodontal problem. This case showed external pressure resorption in the distobuccal root of maxillary second molar caused by the impingement of impacted third molar. Extraction of third molar was decided when healing was not seen, despite initiating endodontic therapy in second molar. Following elevation of flap and extraction of third molar, the poor prognosis due to severe bone loss around the resorbed root was evident. But due to strategic value of second molar, it was found beneficial to employ resection. Therefore, immediate resection was carried out in the same surgical field before the completion of endodontic therapy. This prevented the need for another surgical entry with its associated trauma to carry out resection separately later. Resection followed by the completion of endodontic therapy and full crown assisted in salvaging the remaining functional portion of the tooth and prevented the occurrence of distal extension with its potential drawbacks.

Distinct modes of adventitious rooting in Arabidopsis thaliana.

PubMed

Correa, L da Rocha; Troleis, J; Mastroberti, A A; Mariath, J E A; Fett-Neto, A G

2012-01-01

The literature describes different rooting protocols for Arabidopsis thaliana as models to study adventitious rooting, and results are generally perceived as comparable. However, there is a lack of investigations focusing on the distinct features, advantages and limitations of each method in the study of adventitious rooting with both wild-type (WT) ecotypes and their respective mutants. This investigation was undertaken to evaluate the adventitious rooting process in three different experimental systems, all using A. thaliana, analysing the same rooting parameters after transient exposure to auxin (indole-3-acetic acid) and control conditions: excised leaves, de-rooted plants and etiolated seedlings. The founding tissues and sites of origin of roots differed depending on the system used, whereas all rooting patterns were of the direct type (i.e., without callus formation). None of the systems had an absolute requirement for exogenous auxin, although rooting was enhanced by this phytohormone, with the exception of de-rooted plants, which had adventitious rooting strongly inhibited by exogenous auxin. Root elongation was much favoured in isolated leaves. Auxin-overproducing mutants could not be used in the detached leaf system due to precocious senescence; in the de-rooted plant system, these mutants had a WT-like rooting response, whereas the expression of the 'rooty' phenotype was only evident in the etiolated seedling system. Adventitious rooting of etiolated WT seedlings in the presence of exogenous auxin was inhibited by exogenous flavonoids, which act as auxin transport inhibitors; surprisingly, the flavonoid-deficient mutant chs had a lower rooting response compared to WT. Although Arabidopsis is an excellent model system to study adventitious rooting, physiological and developmental responses differed significantly, underlining the importance of avoiding data generalisation on rooting responses derived from different experimental systems with this species. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

Genome-wide analysis reveals phytohormone action during cassava storage root initiation.

PubMed

Sojikul, Punchapat; Saithong, Treenut; Kalapanulak, Saowalak; Pisuttinusart, Nuttapat; Limsirichaikul, Siripan; Tanaka, Maho; Utsumi, Yoshinori; Sakurai, Tetsuya; Seki, Motoaki; Narangajavana, Jarunya

2015-08-01

Development of storage roots is a process associated with a phase change from cell division and elongation to radial growth and accumulation of massive amounts of reserve substances such as starch. Knowledge of the regulation of cassava storage root formation has accumulated over time; however, gene regulation during the initiation and early stage of storage root development is still poorly understood. In this study, transcription profiling of fibrous, intermediate and storage roots at eight weeks old were investigated using a 60-mer-oligo microarray. Transcription and gene expression were found to be the key regulating processes during the transition stage from fibrous to intermediate roots, while homeostasis and signal transduction influenced regulation from intermediate roots to storage roots. Clustering analysis of significant genes and transcription factors (TF) indicated that a number of phytohormone-related TF were differentially expressed; therefore, phytohormone-related genes were assembled into a network of correlative nodes. We propose a model showing the relationship between KNOX1 and phytohormones during storage root initiation. Exogeneous treatment of phytohormones N (6) -benzylaminopurine and 1-Naphthaleneacetic acid were used to induce the storage root initiation stage and to investigate expression patterns of the genes involved in storage root initiation. The results support the hypothesis that phytohormones are acting in concert to regulate the onset of cassava storage root development. Moreover, MeAGL20 is a factor that might play an important role at the onset of storage root initiation when the root tip becomes swollen.

Clinical study of Mineral Trioxide Aggregate in primary molars. Comparison between Grey and White MTA--a long term follow-up (84 months).

PubMed

Cardoso-Silva, Cristina; Barbería, Elena; Maroto, Myriam; García-Godoy, Franklin

2011-02-01

The aim of the present study was to conduct a clinical and radiographic long-term evaluation of pulpotomy in temporary molars performed with Grey and White Mineral Trioxide Aggregate (MTA) and compare the results of Grey and White MTA pulpotomies in a sample of 233 primary molars with a maximum follow-up period of 84 months. The sample was selected from patients treated at the Department of Pediatric Dentistry, Faculty of Dentistry, Complutense University of Madrid, Spain. This prospective study included first and second primary molars treated with pulpotomy with Grey or White MTA, controlled for a maximum follow-up period of 84 months. Statistical analysis of clinical and radiographic findings was completed using ANOVA (P<0.05). Follow-up evaluations, performed every 6 months, revealed that only 2 molars treated with White MTA presented abscess and pathological mobility. Radiographic examination of the 210 molars revealed unfavourable pulp response in only 6 molars (internal or furcation root resorption), without statistically significant differences between Grey and White MTA. Two radiological findings were noticed: dentine bridge formation and partial or total root canal stenosis. Grey MTA induced a higher percentage of dentine bridges with statistically significant differences (P<0.05), and a higher percentage of pulp canal stenosis, without a statistically significant difference. Grey and White MTA presented high levels of clinical and radiographic success. Although the present study showed evidence of a very good biologic response with both types of MTA, Grey MTA showed significantly higher number of dentine bridge formation than White MTA. Copyright © 2010 Elsevier Ltd. All rights reserved.

The decade of overdentures: 1970-1980.

PubMed

Fenton, A H

1998-01-01

Jaw bones resorb when teeth are lost. People cannot function as well with complete dentures compared with their natural teeth. As more people are living longer and these cumulative effects become increasingly documented, dentists in the 1970s attached more importance to keeping teeth. The concept of overdentures developed as a simple and economic alternative to prolong the retention and function of the last few teeth in a compromised dentition. The previous option was extensive fixed prosthodontics. An overdenture is a complete or removable partial denture that has one or more tooth roots to provide support. Rather than extracting all compromised teeth, the crowns, and pulpal tissue of selected teeth (usually two anterior teeth) are removed. The remaining root projecting through the mucosa is restored and/or contoured. With the crown removed, there is space to cover the area with a denture. The root has less mobility, and its retention retards bone resorption. Overdentures with roots are more stable, and patients can chew better than with dentures supported on residual alveolar bone and mucosal tissue alone. Keeping even a few teeth has a strong psychological value for some patients. Patients who have lost teeth, adjacent tissue, and bone need replacement of more oral structures than tooth crowns alone can provide. A complete denture with flange contours can restore tissue and appearance. The conventional tooth-supported overdenture concept continues to be an accepted treatment modality and has now been adapted to implants.

Ni-silicide growth kinetics in Si and Si/SiO2 core/shell nanowires.

PubMed

Ogata, K; Sutter, E; Zhu, X; Hofmann, S

2011-09-07

A systematic study of the kinetics of axial Ni silicidation of as-grown and oxidized Si nanowires (SiNWs) with different crystallographic orientations and core diameters ranging from ∼ 10 to 100 nm is presented. For temperatures between 300 and 440 °C the length of the total axial silicide intrusion varies with the square root of time, which provides clear evidence that the rate limiting step is diffusion of Ni through the growing silicide phase(s). A retardation of Ni-silicide formation for oxidized SiNWs is found, indicative of a stress induced lowering of the diffusion coefficients. Extrapolated growth constants indicate that the Ni flux through the silicided NW is dominated by surface diffusion, which is consistent with an inverse square root dependence of the silicide length on the NW diameter as observed for (111) orientated SiNWs. In situ TEM silicidation experiments show that NiSi(2) is the first forming phase for as-grown and oxidized SiNWs. The silicide-SiNW interface is thereby atomically abrupt and typically planar. Ni-rich silicide phases subsequently nucleate close to the Ni reservoir, which for as-grown SiNWs can lead to a complete channel break-off for prolonged silicidation due to significant volume expansion and morphological changes.

Ni-Silicide Growth Kinetics in Si and Si/SiO2 Core/Shell Nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hofmann, S.; Sutter, E.; Ogata, K.

A systematic study of the kinetics of axial Ni silicidation of as-grown and oxidized Si nanowires (SiNWs) with different crystallographic orientations and core diameters ranging from {approx} 10 to 100 nm is presented. For temperatures between 300 and 440 C the length of the total axial silicide intrusion varies with the square root of time, which provides clear evidence that the rate limiting step is diffusion of Ni through the growing silicide phase(s). A retardation of Ni-silicide formation for oxidized SiNWs is found, indicative of a stress induced lowering of the diffusion coefficients. Extrapolated growth constants indicate that the Nimore » flux through the silicided NW is dominated by surface diffusion, which is consistent with an inverse square root dependence of the silicide length on the NW diameter as observed for <111> orientated SiNWs. In situ TEM silicidation experiments show that NiSi{sub 2} is the first forming phase for as-grown and oxidized SiNWs. The silicide-SiNW interface is thereby atomically abrupt and typically planar. Ni-rich silicide phases subsequently nucleate close to the Ni reservoir, which for as-grown SiNWs can lead to a complete channel break-off for prolonged silicidation due to significant volume expansion and morphological changes.« less

"Complex Teaching Realities" and "Deep Rooted Cultural Traditions": Barriers to the Implementation and Internalisation of Formative Assessment in China

ERIC Educational Resources Information Center

Poole, Adam; Adamson, Bob

2016-01-01

This article forms the first part of an Action Research project designed to incorporate formative assessment into the culture of learning of a bilingual school in Shanghai, China. It synthesises the empirical literature on formative assessment in China to establish some of the difficulties that teachers have faced in trying to incorporate this…

Truhart-NR, A Root-knot Nematode Resistant, Pimento-type Pepper Cultivar

USDA-ARS?s Scientific Manuscript database

Efforts to develop a high-yielding, pimento-type pepper (Capsicum annuum L.) cultivar that is highly resistant to root-knot nematodes were completed with the official release of Truhart-NR on October 20, 2009. The new cultivar is homozygous for the dominant N gene that conditions a high level of re...

‘Truhart-NR’, A Root-knot Nematode Resistant, Pimento-type Pepper

USDA-ARS?s Scientific Manuscript database

Efforts to develop a high-yielding, pimento-type pepper (Capsicum annuum L.) cultivar that is highly resistant to root-knot nematodes were completed with the official release of Truhart-NR on October 20, 2009. The new cultivar is homozygous for the dominant N gene that conditions a high level of re...

Wilt, crown, and root rot of common rose mallow (Hibiscus moscheutos) caused by a novel Fusarium sp

USDA-ARS?s Scientific Manuscript database

A new crown and root rot disease of landscape plantings of the malvaceous ornamental common rose mallow (Hibiscus moscheutos) was first detected in Washington State in 2012. The main objectives of this study were to complete Koch's postulates, document the disease sypmtoms photographically, and iden...

Staging of third molar development in relation to chronological age of 5-16 year old Indian children.

PubMed

Hegde, Sapna; Patodia, Akash; Dixit, Uma

2016-12-01

The usefulness of the developmental status of the third molar has been studied in assessment of the chronological age of adolescents in whom the development of the other permanent teeth is nearly complete. However, little is known about the timing and pattern of third-molar development in the Indian population. This study aimed to stage the third molar development in relation to chronological age of 5-16year old Indian children. In this cross-sectional observational study, the status of third molar development in relation to chronological age of 1139 Indian children aged 5-16 years was evaluated radiographically, using Orhan's modification of Demirjian's method. The frequency of occurrence of the third molars varied from 47% to 70%. Crypt formation, crown completion and root completion occurred as early as 5.4, 8.7 and 15.0 years, respectively. No significant differences based on gender or side were observed in third-molar development (p>0.05). For most stages, maxillary third molars were slightly more advanced than their mandibular counterparts (p>0.05). Considering the high degree of variability observed in third molar genesis and development, the usefulness of this tooth in age determination studies may be very limited in the age group studied. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Alignment of Ge nanoislands on Si(111) by Ga-induced substrate self-patterning.

PubMed

Schmidt, Th; Flege, J I; Gangopadhyay, S; Clausen, T; Locatelli, A; Heun, S; Falta, J

2007-02-09

A novel mechanism is described which enables the selective formation of three-dimensional Ge islands. Submonolayer adsorption of Ga on Si(111) at high temperature leads to a self-organized two-dimensional pattern formation by separation of the 7 x 7 substrate and Ga/Si(111)-(square root[3] x square root[3])-R30 degrees domains. The latter evolve at step edges and domain boundaries of the initial substrate reconstruction. Subsequent Ge deposition results in the growth of 3D islands which are aligned at the boundaries between bare and Ga-covered domains. This result is explained in terms of preferential nucleation conditions due to a modulation of the surface chemical potential.

Regulation of Auxin Homeostasis and Gradients in Arabidopsis Roots through the Formation of the Indole-3-Acetic Acid Catabolite 2-Oxindole-3-Acetic Acid[C][W][OPEN

PubMed Central

Pěnčík, Aleš; Simonovik, Biljana; Petersson, Sara V.; Henyková, Eva; Simon, Sibu; Greenham, Kathleen; Zhang, Yi; Kowalczyk, Mariusz; Estelle, Mark; Zažímalová, Eva; Novák, Ondřej; Sandberg, Göran; Ljung, Karin

2013-01-01

The native auxin, indole-3-acetic acid (IAA), is a major regulator of plant growth and development. Its nonuniform distribution between cells and tissues underlies the spatiotemporal coordination of many developmental events and responses to environmental stimuli. The regulation of auxin gradients and the formation of auxin maxima/minima most likely involve the regulation of both metabolic and transport processes. In this article, we have demonstrated that 2-oxindole-3-acetic acid (oxIAA) is a major primary IAA catabolite formed in Arabidopsis thaliana root tissues. OxIAA had little biological activity and was formed rapidly and irreversibly in response to increases in auxin levels. We further showed that there is cell type–specific regulation of oxIAA levels in the Arabidopsis root apex. We propose that oxIAA is an important element in the regulation of output from auxin gradients and, therefore, in the regulation of auxin homeostasis and response mechanisms. PMID:24163311

A SWI/SNF Chromatin Remodelling Protein Controls Cytokinin Production through the Regulation of Chromatin Architecture

PubMed Central

Jégu, Teddy; Domenichini, Séverine; Blein, Thomas; Ariel, Federico; Christ, Aurélie; Kim, Soon-Kap; Crespi, Martin; Boutet-Mercey, Stéphanie; Mouille, Grégory; Bourge, Mickaël; Hirt, Heribert; Bergounioux, Catherine; Raynaud, Cécile; Benhamed, Moussa

2015-01-01

Chromatin architecture determines transcriptional accessibility to DNA and consequently gene expression levels in response to developmental and environmental stimuli. Recently, chromatin remodelers such as SWI/SNF complexes have been recognized as key regulators of chromatin architecture. To gain insight into the function of these complexes during root development, we have analyzed Arabidopsis knock-down lines for one sub-unit of SWI/SNF complexes: BAF60. Here, we show that BAF60 is a positive regulator of root development and cell cycle progression in the root meristem via its ability to down-regulate cytokinin production. By opposing both the deposition of active histone marks and the formation of a chromatin regulatory loop, BAF60 negatively regulates two crucial target genes for cytokinin biosynthesis (IPT3 and IPT7) and one cell cycle inhibitor (KRP7). Our results demonstrate that SWI/SNF complexes containing BAF60 are key factors governing the equilibrium between formation and dissociation of a chromatin loop controlling phytohormone production and cell cycle progression. PMID:26457678

Morphogengineering roots: comparing mechanisms of morphogen gradient formation

PubMed Central

2012-01-01

Background In developmental biology, there has been a recent focus on the robustness of morphogen gradients as possible providers of positional information. It was shown that functional morphogen gradients present strong biophysical constraints and lack of robustness to noise. Here we explore how the details of the mechanism which underlies the generation of a morphogen gradient can influence those properties. Results We contrast three gradient-generating mechanisms, (i) a source-decay mechanism; and (ii) a unidirectional transport mechanism; and (iii) a so-called reflux-loop mechanism. Focusing on the dynamics of the phytohormone auxin in the root, we show that only the reflux-loop mechanism can generate a gradient that would be adequate to supply functional positional information for the Arabidopsis root, for biophysically reasonable kinetic parameters. Conclusions We argue that traits that differ in spatial and temporal time-scales can impose complex selective pressures on the mechanism of morphogen gradient formation used for the development of the particular organism. PMID:22583698

Invertebrate ichnofossils and rhizoliths associated with rhizomorphs from the Marília Formation (Echaporã Member), Bauru Group, Upper Cretaceous, Brazil

NASA Astrophysics Data System (ADS)

Mineiro, Adriano Santos; Santucci, Rodrigo Miloni; da Rocha, Dulce Maria Sucena; de Andrade, Marco Brandalise; Nava, William Roberto

2017-12-01

The Marília Formation (Bauru Group, Upper Cretaceous, Brazil) has furnished a large array of vertebrate fossils. However, its ichnological and botanical contents are poorly explored to date. Here we report findings of invertebrate trace fossils (Beaconites isp., Skolithos isp., and Taenidium barretti), rhizoliths associated with rhizomorphs with preserved hyphae, and fossil roots from the Echaporã Member, Marília Formation, São Paulo State, Brazil. The association of trace fossils suggest they can be regarded to the Scoyenia Ichnofacies. The rhizoliths indicate that at least two types of herbaceous/arbustive plants inhabited the area, one of them living in the vadose zone and the other one with roots closer to the water table, under arid/semiarid conditions. Sedimentological analyses suggest the studied outcrop comprises fluvial deposits, with predominance of sand bars that underwent different and relatively long periods of subaerial exposure.

Potential of tissue culture for breeding root-knot nematode resistance into vegetables.

PubMed

Fassuliotis, G; Bhatt, D P

1982-01-01

Plant protoplast technology is being investigated as a means of transferring root-knot nematode resistance factors from Solanum sisymbriifolium into the susceptible S. melongena. Solanum sisymbriifolium plants regenerated from callus lost resistance to Meloidogyne javanica but retained resistance to M. incognita. Tomato plants cloned from leaf discs of the root-knot nematode resistant 'Patriot' were completely susceptible to M. incognita, while sections of stems and leaves rooted in sand in the absence of growth hormones retained resistance. Changes in resistance persisted for three generations. It is postulated that the exogenous hormonal constituents of the culture medium are modifying the expression of genetic resistance.

DNA damage inhibits lateral root formation by up-regulating cytokinin biosynthesis genes in Arabidopsis thaliana.

PubMed

Davis, La Ode Muhammad Muchdar; Ogita, Nobuo; Inagaki, Soichi; Takahashi, Naoki; Umeda, Masaaki

2016-11-01

Lateral roots (LRs) are an important organ for water and nutrient uptake from soil. Thus, control of LR formation is crucial in the adaptation of plant growth to environmental conditions. However, the underlying mechanism controlling LR formation in response to external factors has remained largely unknown. Here, we found that LR formation was inhibited by DNA damage. Treatment with zeocin, which causes DNA double-strand breaks, up-regulated several DNA repair genes in the LR primordium (LRP) through the signaling pathway mediated by the transcription factor SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1). Cell division was severely inhibited in the LRP of zeocin-treated sog1-1 mutant, which in turn inhibited LR formation. This result suggests that SOG1-mediated maintenance of genome integrity is crucial for proper cell division during LRP development. Furthermore, zeocin induced several cytokinin biosynthesis genes in a SOG1-dependent manner, thereby activating cytokinin signaling in the LRP. LR formation was less inhibited by zeocin in mutants defective in cytokinin biosynthesis or signaling, suggesting that elevated cytokinin signaling is crucial for the inhibition of LR formation in response to DNA damage. We conclude that SOG1 regulates DNA repair and cytokinin signaling separately and plays a key role in controlling LR formation under genotoxic stress. © 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

Quantitative Phosphoproteomic Analysis of Soybean Root Hairs Inoculated with Bradyrhizobium japonicum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Tran H.; Brechenmacher, Laurent; Aldrich, Joshua T.

2012-11-11

Root hairs are single hair-forming cells on roots that function to increase root surface area, enhancing water and nutrient uptake. In leguminous plants, root hairs also play a critical role as the site of infection by symbiotic nitrogen fixing rhizobia, leading to the formation of a novel organ, the nodule. The initial steps in the rhizobia-root hair infection process are known to involve specific receptor kinases and subsequent kinase cascades. Here, we characterize the phosphoproteome of the root hairs and the corresponding stripped roots (i.e., roots from which root hairs were removed) during rhizobial colonization and infection to gain insightmore » into the molecular mechanism of root hair cell biology. We chose soybean (Glycine max L.), one of the most important crop plants in the legume family, for this study because of its larger root size, which permits isolation of sufficient root hair material for phosphoproteomic analysis. Phosphopeptides derived from root hairs and stripped roots, mock inoculated or inoculated with the soybean-specific rhizobium Bradyrhizobium japonicum, were labeled with the isobaric tag 8-plex ITRAQ, enriched using Ni-NTA magnetic beads and subjected to nRPLC-MS/MS analysis using HCD and decision tree guided CID/ETD strategy. A total of 1,625 unique phosphopeptides, spanning 1,659 non-redundant phosphorylation sites, were detected from 1,126 soybean phosphoproteins. Among them, 273 phosphopeptides corresponding to 240 phosphoproteins were found to be significantly regulated (>1.5 fold abundance change) in response to inoculation with B. japonicum. The data reveal unique features of the soybean root hair phosphoproteome, including root hair and stripped root-specific phosphorylation suggesting a complex network of kinase-substrate and phosphatase-substrate interactions in response to rhizobial inoculation.« less

Filling a Conical Cavity

NASA Astrophysics Data System (ADS)

Nye, Kyle; Eslam-Panah, Azar

2016-11-01

Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

Biomass partitioning in red pine (Pinus resinosa) along a chronosequence in the Upper Peninsula of Michigan

Treesearch

J.S. King; C.P. Giardina; K.S. Pregitzer; A.L. Friend

2007-01-01

Carbon (C) allocation to the perennial coarse-root system of trees contributes to ecosystem C sequestration through formation of long-lived live wood biomass and, following senescence, by providing a large source of nutrient-poor detrital C. Our understanding of the controls on C allocation to coarse-root growth is rudimentary, but it has important implications for...

As We Teach and Learn: Recognizing Our Catholic Identity. Module 3: Religion Curriculum Articulation: Faith as the Root of All Instruction.

ERIC Educational Resources Information Center

Ford, Elinor R.; Durante, Sheila Rae; Ristau, Karen, Ed.; Haney, Regina, Ed.

The As We Teach and Learn program consists of an instrument to assess the Catholic dimension of a school and is designed to be used with study modules in a faculty-meeting format. Module topics include: "Faith Community"; "Faith Development"; "Religion Curriculum Articulation: Faith as the Root of all Instruction";…

Araloside A, an antiulcer constituent from the root bark of Aralia elata.

PubMed

Lee, Eun Bang; Kim, Oon Ja; Kang, Sam Sik; Jeong, Choonsik

2005-03-01

Araloside A, a potent inhibitor of gastric lesion and ulcer formation in rats, was isolated from the root bark of Aralia elata through a bioassay-guided separation procedure. The compound exhibited significant reduction of HCl.ethanol-induced gastric lesions and aspirin-induced gastric ulcers at oral doses of 50 and 100 mg/kg, respectively. These activities are comparable to those of cimetidine.

Rapid dental development in a Middle Paleolithic Belgian Neanderthal

PubMed Central

Smith, Tanya M.; Toussaint, Michel; Reid, Donald J.; Olejniczak, Anthony J.; Hublin, Jean-Jacques

2007-01-01

The evolution of life history (pace of growth and reproduction) was crucial to ancient hominin adaptations. The study of dental development facilitates assessment of growth and development in fossil hominins with greater precision than other skeletal analyses. During tooth formation, biological rhythms manifest in enamel and dentine, creating a permanent record of growth rate and duration. Quantification of these internal and external incremental features yields developmental benchmarks, including ages at crown completion, tooth eruption, and root completion. Molar eruption is correlated with other aspects of life history. Recent evidence for developmental differences between modern humans and Neanderthals remains ambiguous. By measuring tooth formation in the entire dentition of a juvenile Neanderthal from Scladina, Belgium, we show that most teeth formed over a shorter time than in modern humans and that dental initiation and eruption were relatively advanced. By registering manifestations of stress across the dentition, we are able to present a precise chronology of Neanderthal dental development that differs from modern humans. At 8 years of age at death, this juvenile displays a degree of development comparable with modern human children who are several years older. We suggest that age at death in juvenile Neanderthals should not be assessed by comparison with modern human standards, particularly those derived from populations of European origin. Moreover, evidence from the Scladina juvenile and other similarly aged hominins suggests that a prolonged childhood and slow life history are unique to Homo sapiens. PMID:18077342

Acute aortic dissection involving the root: operative and long-term outcome after curative proximal repair†

PubMed Central

Urbanski, Paul P.; Lenos, Aristidis; Irimie, Vadim; Bougioukakis, Petros; Zacher, Michael; Diegeler, Anno

2016-01-01

OBJECTIVES The aim of the study was to evaluate operative and long-term results after surgery of acute aortic dissection involving the root, in which the proximal repair consisted of curative resection of all dissected aortic sinuses and was performed using either valve-sparing root repair or complete root replacement with a valve conduit. METHODS Between August 2002 and March 2013, 162 consecutive patients (mean age 63 ± 14 years) underwent surgery for acute type A aortic dissection. Eighty-six patients with an involvement of the aortic root underwent curative surgery of the proximal aorta consisting of valve-sparing root repair (n = 54, 62.8%) or complete valve and root replacement using composite valve grafts (n = 32, 37.2%). In patients with root repair, all dissected aortic walls were resected and root remodelling using the single patch technique (n = 53) or root repair with valve reimplantation (n = 1) was performed without the use of any glue. All perioperative data were collected prospectively and retrospective statistical examination was performed using univariate and multivariate analyses. RESULTS The mean follow-up was 5.2 ± 3.5 years for all patients (range 0–12 years) and 6.1 ± 3.3 years for survivors. The 30-day mortality rate was 5.8% (5 patients), being considerably lower in the repair sub-cohort (1.9 vs 12.5%). The estimated survival rate at 5 and 10 years was 80.0 ± 4.5 and 69.1 ± 6.7%, respectively. No patient required reoperation on the proximal aorta and/or aortic valve during the follow-up time and there were only two valve-related events (both embolic, one in each group). Among those patients with repaired valves, the last echocardiography available showed no insufficiency in 40 and an irrelevant insufficiency (1+) in 14. CONCLUSIONS Curative repair of the proximal aorta in acute dissection involving the root provides favourable operative and long-term outcome with very low risk of aortic complications and/or reoperations, regardless if a valve-sparing procedure or replacement with a valve conduit is used. Valve-sparing surgery is frequently suitable, providing excellent outcome and very high durability. PMID:26848190

Acetylcholine causes rooting in leaf explants of in vitro raised tomato (Lycopersicon esculentum Miller) seedlings.

PubMed

Bamel, Kiran; Gupta, Shrish Chandra; Gupta, Rajendra

2007-05-30

The animal neurotransmitter acetylcholine (ACh) induces rooting and promotes secondary root formation in leaf explants of tomato (Lycopersicon esculentum Miller var. Pusa Ruby), cultured in vitro on Murashige and Skoog's medium. The roots originate from the midrib of leaf explants and resemble taproot. ACh at 10(-5) M was found to be the optimum over a wide range of effective concentrations between 10(-7) and 10(-3) M. The breakdown products, choline and acetate were ineffective even at 10(-3) M concentration. ACh appears to have a natural role in tomato rhizogenesis because exogenous application of neostigmine, an inhibitor of ACh hydrolysis, could mimic the effect of ACh. Neostigmine, if applied in combination with ACh, potentiated the ACh effect.

Basipetal auxin transport is required for gravitropism in roots of Arabidopsis

NASA Technical Reports Server (NTRS)

Rashotte, A. M.; Brady, S. R.; Reed, R. C.; Ante, S. J.; Muday, G. K.; Davies, E. (Principal Investigator)

2000-01-01

Auxin transport has been reported to occur in two distinct polarities, acropetally and basipetally, in two different root tissues. The goals of this study were to determine whether both polarities of indole-3-acetic acid (IAA) transport occur in roots of Arabidopsis and to determine which polarity controls the gravity response. Global application of the auxin transport inhibitor naphthylphthalamic acid (NPA) to roots blocked the gravity response, root waving, and root elongation. Immediately after the application of NPA, the root gravity response was completely blocked, as measured by an automated video digitizer. Basipetal [(3)H]IAA transport in Arabidopsis roots was inhibited by NPA, whereas the movement of [(14)C]benzoic acid was not affected. Inhibition of basipetal IAA transport by local application of NPA blocked the gravity response. Inhibition of acropetal IAA transport by application of NPA at the root-shoot junction only partially reduced the gravity response at high NPA concentrations. Excised root tips, which do not receive auxin from the shoot, exhibited a normal response to gravity. The Arabidopsis mutant eir1, which has agravitropic roots, exhibited reduced basipetal IAA transport but wild-type levels of acropetal IAA transport. These results support the hypothesis that basipetally transported IAA controls root gravitropism in Arabidopsis.

Action of Chlorhexidine, Zingiber officinale, and Calcium Hydroxide on Candida albicans, Enterococcus faecalis, Escherichia coli, and Endotoxin in the Root Canals.

PubMed

Valera, Marcia C; Oliveira, Sarah Ac; Maekawa, Lilian E; Cardoso, Flávia Gr; Chung, Adriana; Silva, Stephanie Fp; Carvalho, Cláudio At

2016-02-01

The purpose of this in vitro study was to evaluate the antimicrobial activity of 2% chlorhexidine gel (CHX) as auxiliary chemical substance and intracanal medications on Candida albicans, Enterococcus faecalis, Escherichia coli, and their endotoxins in the root canals. The study was conducted on 48 single-rooted human teeth divided into four groups (n = 12), according to intracanal medications used: (1) Calcium hydroxide + apyrogenic saline solution (Ca(OH)2 + SS), (2) 20% ginger glycolic extract (GEN), (3) calcium hydroxide + 20% ginger glycolic extract (Ca(OH)2 + GEN), (4) apyrogenic SS (control). Collections were made from the root canal content before preparation (baseline-S1), immediately after instrumentation (S2), 7 days after instrumentation (S3), after 14 days the action of intracanal medication (S4), and 7 days after removal of the intracanal medication (S5). The antimicrobial activity and endotoxin content were analyzed for all collections. The results were statistically analyzed by the Kruskal-Wallis and Dunn tests at a significance level of 5%. After instrumentation with CHX, there was complete elimination of E. coli and C. albicans, except for E. faecalis, which was significantly reduced and then completely eliminated after intracanal medication. There was significant reduction of endotoxin after instrumentation. Comparison of collection after instrumentation and intracanal medication revealed reduction of endotoxins in all groups; this reduction was greater in group Ca(OH)2 followed by the group GEN. It was concluded that the instrumentation using CHX and intracanal medication used were able to eliminate the microorganisms from the root canal; the endotoxins were reduced, yet not completely eliminated. This study is important and relevant for searching alternatives during endodontic therapy, since it aims to study the effect of Zingiber officinale on microorganisms and endotoxins present in root canals.

Blue light does not inhibit nodulation in Sesbania rostrata.

PubMed

Shimomura, Aya; Arima, Susumu; Hayashi, Makoto; Maymon, Maskit; Hirsch, Ann M; Suzuki, Akihiro

2017-01-02

Earlier, we reported that root nodulation was inhibited by blue light irradiation of Lotus japonicus. Because some legumes do not establish nodules exclusively on underground roots, we investigated whether nodule formation in Sesbania rostrata, which forms both root and "stem" nodules following inoculation with Azorhizobium caulinodans, is inhibited by blue light as are L. japonicus nodules. We found that neither S. rostrata nodulation nor nitrogen fixation was inhibited by blue light exposure. Moreover, although A. caulinodans proliferation was not affected by blue light irradiation, bacterial survival was decreased. Therefore, blue light appears to impose different responses depending on the legume-rhizobial symbiosis.

Plant grafting: new mechanisms, evolutionary implications.

PubMed

Goldschmidt, Eliezer E

2014-01-01

Grafting, an old plant propagation practice, is still widely used with fruit trees and in recent decades also with vegetables. Taxonomic proximity is a general prerequisite for successful graft-take and long-term survival of the grafted, composite plant. However, the mechanisms underlying interspecific graft incompatibility are as yet insufficiently understood. Hormonal signals, auxin in particular, are believed to play an important role in the wound healing and vascular regeneration within the graft union zone. Incomplete and convoluted vascular connections impede the vital upward and downward whole plant transfer routes. Long-distance protein, mRNA and small RNA graft-transmissible signals currently emerge as novel mechanisms which regulate nutritional and developmental root/top relations and may play a pivotal role in grafting physiology. Grafting also has significant pathogenic projections. On one hand, stock to scion mechanical contact enables the spread of diseases, even without a complete graft union. But, on the other hand, grafting onto resistant rootstocks serves as a principal tool in the management of fruit tree plagues and vegetable soil-borne diseases. The 'graft hybrid' historic controversy has not yet been resolved. Recent evidence suggests that epigenetic modification of DNA-methylation patterns may account for certain graft-transformation phenomena. Root grafting is a wide spread natural phenomenon; both intraspecific and interspecific root grafts have been recorded. Root grafts have an evolutionary role in the survival of storm-hit forest stands as well as in the spread of devastating diseases. A more fundamental evolutionary role is hinted by recent findings that demonstrate plastid and nuclear genome transfer between distinct Nicotiana species in the graft union zone, within a tissue culture system. This has led to the formation of alloploid cells that, under laboratory conditions, gave rise to a novel, alloploid Nicotiana species, indicating that natural grafts may play a role in plant speciation, under certain circumstances.

Herbicidal cyanoacrylates with antimicrotubule mechanism of action.

PubMed

Tresch, Stefan; Plath, Peter; Grossmann, Klaus

2005-11-01

The herbicidal mode of action of the new synthetic cyanoacrylates ethyl (2Z)-3-amino-2-cyano-4-ethylhex-2-enoate (CA1) and its isopropyl ester derivative CA2 was investigated. For initial characterization, a series of bioassays was used indicating a mode of action similar to that of mitotic disrupter herbicides such as the dinitroaniline pendimethalin. Cytochemical fluorescence studies including monoclonal antibodies against polymerized and depolymerized tubulin and a cellulose-binding domain of a bacterial cellulase conjugated to a fluorescent dye were applied to elucidate effects on cell division processes including mitosis and microtubule and cell wall formation in maize roots. When seedlings were root treated with 10 microM of CA1 or CA2, cell division activity in meristematic root tip cells decreased within 4 h. The chromosomes proceeded to a condensed state of prometaphase, but were unable to progress further in the mitotic cycle. The compounds caused a complete loss of microtubular structures, including preprophase, spindle, phragmoplast and cortical microtubules. Concomitantly, in the cytoplasm, an increase in labelling of free tubulin was observed. This suggests that the herbicides disrupt polymerization and microtubule stability, whereas tubulin synthesis or degradation appeared not to be affected. In addition, cellulose labelling in cell walls of root tip cells was not influenced. The effects of CA1 and CA2 were comparable with those caused by pendimethalin. In transgenic Arabidopsis plants expressing a green fluorescent protein-microtubule-associated protein4 fusion protein, labelled arrays of cortical microtubules in living epidermal cells of hypocotyls collapsed within 160 min after exposure to 10 microM CA1 or pendimethalin. Moreover, a dinitroaniline-resistant biotype of goosegrass (Eleusine indica (L) Gaertn) with a point mutation in alpha-tubulin showed cross-resistance against CA1 and CA2. The results strongly indicate that the cyanoacrylates are a new chemical class of herbicide which possess the same antimicrotubule mechanism of action as dinitroanilines, probably including interaction with the same binding site in alpha-tubulin. Copyright 2005 Society of Chemical Industry.

Plant grafting: new mechanisms, evolutionary implications

PubMed Central

Goldschmidt, Eliezer E.

2014-01-01

Grafting, an old plant propagation practice, is still widely used with fruit trees and in recent decades also with vegetables. Taxonomic proximity is a general prerequisite for successful graft-take and long-term survival of the grafted, composite plant. However, the mechanisms underlying interspecific graft incompatibility are as yet insufficiently understood. Hormonal signals, auxin in particular, are believed to play an important role in the wound healing and vascular regeneration within the graft union zone. Incomplete and convoluted vascular connections impede the vital upward and downward whole plant transfer routes. Long-distance protein, mRNA and small RNA graft-transmissible signals currently emerge as novel mechanisms which regulate nutritional and developmental root/top relations and may play a pivotal role in grafting physiology. Grafting also has significant pathogenic projections. On one hand, stock to scion mechanical contact enables the spread of diseases, even without a complete graft union. But, on the other hand, grafting onto resistant rootstocks serves as a principal tool in the management of fruit tree plagues and vegetable soil-borne diseases. The ‘graft hybrid’ historic controversy has not yet been resolved. Recent evidence suggests that epigenetic modification of DNA-methylation patterns may account for certain graft-transformation phenomena. Root grafting is a wide spread natural phenomenon; both intraspecific and interspecific root grafts have been recorded. Root grafts have an evolutionary role in the survival of storm-hit forest stands as well as in the spread of devastating diseases. A more fundamental evolutionary role is hinted by recent findings that demonstrate plastid and nuclear genome transfer between distinct Nicotiana species in the graft union zone, within a tissue culture system. This has led to the formation of alloploid cells that, under laboratory conditions, gave rise to a novel, alloploid Nicotiana species, indicating that natural grafts may play a role in plant speciation, under certain circumstances. PMID:25566298

Growth of cress seedlings and morphogenesis of root Gravisensors under clino-rotation and in unidirectional red or blue light

NASA Astrophysics Data System (ADS)

Rakleviciene, D.; Svegzdiene, D.; Tamulaitis, G.; Zukauskas, A.

2005-08-01

The growth rate and orientation of cress seedlings in response to the direction of illumination under clino- rotation were investigated at the initial stage of intensive hypocotyl elongation. Roots and hypocotyls growing in normal gravity conditions (1 g) and under clino-rotation at 3 rpm were illuminated with red (660 nm) or blue (450 nm) light from light-emitting diodes (LEDs). Unidirectional illumination in the direction opposite to the gravity vector promoted the growth rate of roots. Inhibition of gravitropism by clino-rotation reduced the growth of roots and stimulated the elongation of hypocotyls in both red and blue light. Illumination of roots invoked changes in the formation of gravisensing cells in the columella. Illumination under clino-rotation stimulated root statocyte growth and increased the number of amyloplasts in cells of the 3rd-6th columella rows. Also, an increase in the columella cell area, mainly caused by cell elongation in blue light and by enhanced radial growth in red light, was observed.