Disruptions in valine degradation affect seed development and germination in Arabidopsis.

PubMed

Gipson, Andrew B; Morton, Kyla J; Rhee, Rachel J; Simo, Szabolcs; Clayton, Jack A; Perrett, Morgan E; Binkley, Christiana G; Jensen, Erika L; Oakes, Dana L; Rouhier, Matthew F; Rouhier, Kerry A

2017-06-01

We have functionally characterized the role of two putative mitochondrial enzymes in valine degradation using insertional mutants. Prior to this study, the relationship between branched-chain amino acid degradation (named for leucine, valine and isoleucine) and seed development was limited to leucine catabolism. Using a reverse genetics approach, we show that disruptions in the mitochondrial valine degradation pathway affect seed development and germination in Arabidopsis thaliana. A null mutant of 3-hydroxyisobutyryl-CoA hydrolase (CHY4, At4g31810) resulted in an embryo lethal phenotype, while a null mutant of methylmalonate semialdehyde dehydrogenase (MMSD, At2g14170) resulted in seeds with wrinkled coats, decreased storage reserves, elevated valine and leucine, and reduced germination rates. These data highlight the unique contributions CHY4 and MMSD make to the overall growth and viability of plants. It also increases our knowledge of the role branched-chain amino acid catabolism plays in seed development and amino acid homeostasis. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

A sunflower WRKY transcription factor stimulates the mobilization of seed-stored reserves during germination and post-germination growth.

PubMed

Raineri, Jesica; Hartman, Matías D; Chan, Raquel L; Iglesias, Alberto A; Ribichich, Karina F

2016-09-01

The sunflower transcription factor HaWRKY10 stimulates reserves mobilization in Arabidopsis. Gene expression and enzymes activity assays indicated that lipolysis and gluconeogenesis were increased. Microarray results suggested a parallelism in sunflower. Germinating oilseeds converts stored lipids into sugars, and thereafter in metabolic energy that is used in seedling growth and establishment. During germination, the induced lipolysis linked to the glyoxylate pathway and gluconeogenesis produces sucrose, which is then transported to the embryo and driven through catabolic routes. Herein, we report that the sunflower transcription factor HaWRKY10 regulates carbon partitioning by reducing carbohydrate catabolism and increasing lipolysis and gluconeogenesis. HaWRKY10 was regulated by abscisic acid and gibberellins in the embryo leaves 48 h after seed imbibition and highly expressed during sunflower seed germination and seedling growth, concomitantly with lipid mobilization. Sunflower leaf disks overexpressing HaWRKY10 showed repressed expression of genes related to sucrose cleavage and glycolysis compared with controls. Moreover, HaWRKY10 constitutive expression in Arabidopsis seeds produced higher decrease in lipid reserves, whereas starch and sucrose were more preserved compared with wild type. Gene transcripts abundance and enzyme activities involved in stored lipid mobilization and gluconeogenesis increased more in transgenic than in wild type seeds 36 h after imbibition, whereas the negative regulator of lipid mobilization, ABI4, was repressed. Altogether, the results point out a functional parallelism between tissues and plant species, and reveal HaWRKY10 as a positive regulator of storage reserve mobilization in sunflower.

[Biotic and abiotic factors that affect the quality of Schinopsis balansae Engl. and Aspidosperma quebracho-blanco Schltdl. seeds].

PubMed

Alzugaray, Claudia; Carnevale, Nélida J; Salinas, Adriana R; Pioli, Rosanna

2007-06-01

Aspidosperma quebracho-blanco (white quebracho) and Schinopsis balansae (red quebracho) are distinctive trees of the South American Park in Argentina. Quebrachos are found in forests that have been exploited very intensively. The object of this work was the identification of biotic and abiotic factors specially fungal pathogen that affect the quality of both species and its relation with germination. Seeds where evaluated through germination test and the percentage of the incidence of fungal agents in two different years of harvest was determined. In S. balansae the germination rate was 77% and of 27% in 2000 and 2001 harvests, respectively. Associations fungi-germination were found in 2001 for Alternaria spp., Curvularia spp., and Fusarium spp., showing an coefficient of correlation = -0.84; -0.85 and -0.73 (p < 0.00004), respectively. A high percentage of vane seeds (55%) was also found in 2001 harvest, due to adverse environmental factors, specifically higher precipitations during flowering. In A. quebracho-blanco seeds, the germination rate was 50% and 90% in 2000 and 2003 respectively, with a 42% of immature seeds in 2000 harvest that was associated to high precipitations and high temperatures during flowering and ripping of fruits. The incidence of pathogens was low and did not have association to germination.

Selective inhibition of Erwinia amylovora by the herbicidally-active Germination-Arrest Factor (GAF) produced by Pseudomonas bacteria

USDA-ARS?s Scientific Manuscript database

Aims: The Germination-Arrest Factor (GAF) produced by Pseudomonas fluorescens WH6, and identified as 4-formylaminooxyvinylglycine, specifically inhibits the germination of a wide range of grassy weeds. The present study was undertaken to determine if GAF has antimicrobial activity in addition to it...

Seed germination in response to chemicals: effect of nitrogen and pH in the media.

PubMed

Pérez-Fernández, M A; Calvo-Magro, E; Montanero-Fernández, J; Oyola-Velasco, J A

2006-01-01

Seed germination generally presents a peak in the next growing season after a fire. Among other factors associated with fire are the increase of soil nitrogen and changes in the pH of the soil. In this study, we addressed the question, whether or not the germination response of eight species is linked with the increase in pH and nitrogenous compounds in the germination media? We assessed the separate and combined effects of nitrogenous compounds and pH on the percentage and rate of germination of seeds of Medicago arabica (L.) Hudson, Epilobium hirsutum L., Foeniculum vulgare Miller, Daucus carota L., Thapsia villosa L., Cynosurus cristatus L., Dactylis glomerata L. and Rumex crispus L. All these species are well represented in the Mediterranean ecosystems of the central-west Spain. Water and CaCl2 were used as controls. Nitrogenous compounds increased percent germination (level) and rate in three of the species studied. High pH negatively affected the germination rate of seeds from most species, but had no effect on the per cent germination of any of the species. The higher concentration of the nutritious solutions affected negatively the germination level and rate. The different germination responses of seeds of the studied species could not be exclusively attributed to pH values in the media, whereas the amount and form of Nitrogen in the media has a greater effect on it. These differences in germination are species dependent.

Germination of Ocotea pulchella (Nees) Mez (Lauraceae) seeds in laboratory and natural restinga environment conditions.

PubMed

Pires, L A; Cardoso, V J M; Joly, C A; Rodrigues, R R

2009-08-01

The germination response of Ocotea pulchella (Nees) Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 degrees C, the minimum or base temperature estimated was 11 degrees C and the maximum ranged between 33 and 42 degrees C. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor.

Prediction of cheatgrass field germination potential using wet thermal accumulation

Treesearch

Bruce A. Roundy; Stuart P. Hardegree; Jeane C. Chambers; Alison Whittaker

2007-01-01

Invasion and dominance of weedy species is facilitated or constrained by environmental and ecological factors that affect resource availability during critical life stages. We compared the relative effects of season, annual weather, site, and disturbance on potential cheatgrass (Bromus tectorum L.) germination in big sagebrush (Artemisia...

Effect of soaking and germination on physicochemical and functional attributes of horsegram flour.

PubMed

Handa, Vanshika; Kumar, Vikas; Panghal, Anil; Suri, Sheenam; Kaur, Jaspreet

2017-12-01

Horsegram is an underutilized pulse, traditionally used for treating various disorders like kidney stones, diabetes and joint pain. The present study was undertaken to optimize the soaking and germination conditions, to decrease the anti-nutritional factors and at the same time maintaining the nutritional properties of horsegram. Horsegram seeds were soaked for 6, 12 and 18 h followed by germination for 0, 24 and 48 h under different illumination conditions i.e., light and dark respectively. The soaked and germinated samples were dried in laboratory drier at 55 °C until constant moisture was achieved and was further analyzed for various quality attributes. Almost all the physicochemical and functional characteristics were significantly affected by both soaking and germination, whereas, germination done in light and dark conditions, exerted significant effect on the ascorbic acid content, total protein, total phenols, antioxidant activity and tannin content only. Based on the quality attributes, it was found that treatment having 18 h soaking and 48 h germination in the presence of light was the best where maximum decrease in the anti-nutritional factors was observed. Moreover, there was an increase in ascorbic acid, total protein content and a decrease in the anti-nutritional factors such as oxalate and tannin content. Thus, it is concluded that 18 h soaking and 48 h germination in the presence of light can be considered as the optimum conditions to increase the nutritional content of horsegram flour, which can further be utilized for the preparation of different value-added food products.

Influence of Environmental Factors on the Germination of Urena lobata L. and Its Response to Herbicides

PubMed Central

Awan, Tahir Hussain; Chauhan, Bhagirath Singh; Cruz, Pompe C. Sta.

2014-01-01

Urena lobata is becoming a noxious and invasive weed in rangelands, pastures, and undisturbed areas in the Philippines. This study determined the effects of seed scarification, light, salt and water stress, amount of rice residue, and seed burial depth on seed germination and emergence of U. lobata; and evaluated the weed's response to post-emergence herbicides. Germination was stimulated by both mechanical and chemical seed scarifications. The combination of the two scarification methods provided maximum (99%) seed germination. Germination was slightly stimulated when seeds were placed in light (65%) compared with when seeds were kept in the dark (46%). Sodium chloride concentrations ranging from 0 to 200 mM and osmotic potential ranging from 0 to −1.6 MPa affected the germination of U. lobata seeds significantly. The osmotic potential required for 50% inhibition of the maximum germination was −0.1 MPa; however, some seeds germinated at −0.8 MPa, but none germinated at −1.6 MPa. Seedling emergence and biomass increased with increase in rice residue amount up to 4 t ha−1, but declined beyond this amount. Soil surface placement of weed seeds resulted in the highest seedling emergence (84%), which declined with increase in burial depth. The burial depth required for 50% inhibition of maximum emergence was 2 cm; emergence was greatly reduced (93%) at burial depth of 4 cm or more. Weed seedling biomass also decreased with increase in burial depth. Bispyribac-sodium, a commonly used herbicide in rice, sprayed at the 4-leaf stage of the weed, provided 100% control, which did not differ much with 2,4-D (98%), glyphosate (97%), and thiobencarb + 2,4-D (98%). These herbicides reduced shoot and root biomass by 99–100%. PMID:24658143

Does cattle dung cause differences between grazing increaser and decreaser germination response?

NASA Astrophysics Data System (ADS)

Carmona, Carlos P.; Azcárate, Francisco M.; Peco, Begoña

2013-02-01

Although grassland species are usually classified as grazing increasers or decreasers, the response mechanisms to herbivore action in these two groups have yet to be clarified. One such action is dung deposition. The present study tested the hypothesis that increaser species perform more efficiently than decreasers during germination and/or establishment in the presence of dung leachates. A phytotron experiment was conducted on fourteen Mediterranean grassland species from five families, with an equal number of increaser and decreaser species chosen for each family to control for phylogeny. Seeds were germinated and grown in different concentrations of cattle dung leachate. We monitored germination percentages, median germination time and root length, measured five days after germination. To analyse the response and identify potential thresholds, we fitted piecewise mixed models using family/species as nested random factors. Differences in germination parameters between the two groups peaked in favour of increasers under intermediate leachate concentrations. Root growth was also negatively affected by leachates in decreaser species and promoted in increasers. Livestock dung deposition can increase the germination and colonising performance of increasers over decreasers, and may therefore be one of the mechanisms that explain the different species composition of grazed and ungrazed environments.

Effect of surfactants and temperature on germination and vegetative growth of Beauveria bassiana.

PubMed

Mwamburi, Lizzy A; Laing, Mark D; Miller, Ray M

2015-03-01

Three non-ionic surfactants: Tween20, Tween80 and Breakthru (®) were screened for their effects on spore germination and mycelial growth rates and for their influence on three isolates of Beauveria bassiana spore germination at various temperatures. Tween20 and Tween80 were compatible with all the B. bassiana isolates in the germination studies, but inhibited germination at higher surfactant concentrations, irrespective of the conidial concentrations . Breakthru (®) had an inhibitory effect on germination even at the lowest concentration of 0.1% on all the B. bassiana isolates. The effects of the surfactants on spore germination did not correspond with their effects on colony growth. Conidial viability within the same formulation declined significantly with increases in temperature, irrespective of the surfactant. The optimal temperature for conidial germination of B. bassiana isolates was approximately 25 °C with an upper limit at 30 °C. Isolate 7320 was identified as the least affected by the different surfactants. This isolate was able to germinate rapidly in a broad temperature range of 25-30 °C after 24 h, this characteristic being an essential factor in controlling house fly populations in poultry houses.

Effect of surfactants and temperature on germination and vegetative growth of Beauveria bassiana

PubMed Central

Mwamburi, Lizzy A.; Laing, Mark D.; Miller, Ray M.

2015-01-01

Three non-ionic surfactants: Tween20, Tween80 and Breakthru ® were screened for their effects on spore germination and mycelial growth rates and for their influence on three isolates of Beauveria bassiana spore germination at various temperatures. Tween20 and Tween80 were compatible with all the B. bassiana isolates in the germination studies, but inhibited germination at higher surfactant concentrations, irrespective of the conidial concentrations . Breakthru ® had an inhibitory effect on germination even at the lowest concentration of 0.1% on all the B. bassiana isolates. The effects of the surfactants on spore germination did not correspond with their effects on colony growth. Conidial viability within the same formulation declined significantly with increases in temperature, irrespective of the surfactant. The optimal temperature for conidial germination of B. bassiana isolates was approximately 25 °C with an upper limit at 30 °C. Isolate 7320 was identified as the least affected by the different surfactants. This isolate was able to germinate rapidly in a broad temperature range of 25–30 °C after 24 h, this characteristic being an essential factor in controlling house fly populations in poultry houses. PMID:26221090

Monitoring of Commitment, Blocking, and Continuation of Nutrient Germination of Individual Bacillus subtilis Spores

PubMed Central

Zhang, Pengfei; Liang, Jintao; Yi, Xuan; Setlow, Peter

2014-01-01

Short exposures of Bacillus spores to nutrient germinants can commit spores to germinate when germinants are removed or their binding to the spores' nutrient germinant receptors (GRs) is inhibited. Bacillus subtilis spores were exposed to germinants for various periods, followed by germinant removal to prevent further commitment. Release of spore dipicolinic acid (DPA) was then measured by differential interference contrast microscopy to monitor germination of multiple individual spores, and spores did not release DPA after 1 to 2 min of germinant exposure until ∼7 min after germinant removal. With longer germinant exposures, percentages of committed spores with times for completion of DPA release (Trelease) greater than the time of germinant removal (Tb) increased, while the time Tlag − Tb, where Tlag represents the time when rapid DPA release began, was decreased but rapid DPA release times (ΔTrelease = Trelease − Tlag) were increased; Factors affecting average Trelease values and the percentages of committed spores were germinant exposure time, germinant concentration, sporulation conditions, and spore heat activation, as previously shown for commitment of spore populations. Surprisingly, germination of spores given a 2nd short germinant exposure 30 to 45 min after a 1st exposure of the same duration was significantly higher than after the 1st exposure, but the number of spores that germinated in the 2nd germinant exposure decreased as the interval between germinant exposures increased up to 12 h. The latter results indicate that spores have some memory, albeit transient, of their previous exposure to nutrient germinants. PMID:24769693

Variation in Seed Germination of 134 Common Species on the Eastern Tibetan Plateau: Phylogenetic, Life History and Environmental Correlates

PubMed Central

Xu, Jing; Li, Wenlong; Zhang, Chunhui; Liu, Wei; Du, Guozhen

2014-01-01

Seed germination is a crucial stage in the life history of a species because it represents the pathway from adult to offspring, and it can affect the distribution and abundance of species in communities. In this study, we examined the effects of phylogenetic, life history and environmental factors on seed germination of 134 common species from an alpine/subalpine meadow on the eastern Tibetan Plateau. In one-way ANOVAs, phylogenetic groups (at or above order) explained 13.0% and 25.9% of the variance in germination percentage and mean germination time, respectively; life history attributes, such as seed size, dispersal mode, explained 3.7%, 2.1% of the variance in germination percentage and 6.3%, 8.7% of the variance in mean germination time, respectively; the environmental factors temperature and habitat explained 4.7%, 1.0% of the variance in germination percentage and 13.5%, 1.7% of the variance in mean germination time, respectively. Our results demonstrated that elevated temperature would lead to a significant increase in germination percentage and an accelerated germination. Multi-factorial ANOVAs showed that the three major factors contributing to differences in germination percentage and mean germination time in this alpine/subalpine meadow were phylogenetic attributes, temperature and seed size (explained 10.5%, 4.7% and 1.4% of the variance in germination percentage independently, respectively; and explained 14.9%, 13.5% and 2.7% of the variance in mean germination time independently, respectively). In addition, there were strong associations between phylogenetic group and life history attributes, and between life history attributes and environmental factors. Therefore, germination variation are constrained mainly by phylogenetic inertia in a community, and seed germination variation correlated with phylogeny is also associated with life history attributes, suggesting a role of niche adaptation in the conservation of germination variation within lineages

Biorhythms in conifer seed germination during extended storage

Treesearch

James P. Barnett; N.I. Marnonov

1989-01-01

A proportion of sound seeds of conifer species do not germinate during certain periods of the year, even when conditions are favorable. Mamonov et al. (1986) report that the non-germinating seeds have apparently undergone physiological changes that affected germination. This phenomenon may be due to seasonal periodicity, or biorhythms. As early as the mid-1930'...

Germination biology of Hibiscus tridactylites in Australia and the implications for weed management

PubMed Central

Chauhan, Bhagirath Singh

2016-01-01

Hibiscus tridactylites is a problematic broadleaf weed in many crops in Australia; however, very limited information is available on seed germination biology of Australian populations. Experiments were conducted to evaluate the effect of environmental factors on germination and emergence of H. tridactylites. Germination was stimulated by seed scarification, suggesting the inhibition of germination in this species is mainly due to the hard seed coat. Germination was not affected by light conditions, suggesting that seeds of this species are not photoblastic. Germination was higher at alternating day/night temperatures of 30/20 °C (74%) and 35/25 °C (69%) than at 25/15 °C (63%). Moderate salinity and water stress did not inhibit germination of H. tridactylites. Seedling emergence of H. tridactylites was highest (57%) for the seeds buried at a 2 cm depth in the soil; 18% of seedlings emerged from seeds buried at 8 cm but no seedlings emerged below this depth. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence could serve an important tool for managing H. tridactylites. PMID:27174752

Germination biology of Hibiscus tridactylites in Australia and the implications for weed management

NASA Astrophysics Data System (ADS)

Chauhan, Bhagirath Singh

2016-05-01

Hibiscus tridactylites is a problematic broadleaf weed in many crops in Australia; however, very limited information is available on seed germination biology of Australian populations. Experiments were conducted to evaluate the effect of environmental factors on germination and emergence of H. tridactylites. Germination was stimulated by seed scarification, suggesting the inhibition of germination in this species is mainly due to the hard seed coat. Germination was not affected by light conditions, suggesting that seeds of this species are not photoblastic. Germination was higher at alternating day/night temperatures of 30/20 °C (74%) and 35/25 °C (69%) than at 25/15 °C (63%). Moderate salinity and water stress did not inhibit germination of H. tridactylites. Seedling emergence of H. tridactylites was highest (57%) for the seeds buried at a 2 cm depth in the soil; 18% of seedlings emerged from seeds buried at 8 cm but no seedlings emerged below this depth. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence could serve an important tool for managing H. tridactylites.

Integration of Auxin and Salt Signals by the NAC Transcription Factor NTM2 during Seed Germination in Arabidopsis1[W

PubMed Central

Park, Jungmin; Kim, Youn-Sung; Kim, Sang-Gyu; Jung, Jae-Hoon; Woo, Je-Chang; Park, Chung-Mo

2011-01-01

Seed germination is regulated through elaborately interacting signaling networks that integrate diverse environmental cues into hormonal signaling pathways. Roles of gibberellic acid and abscisic acid in germination have been studied extensively using Arabidopsis (Arabidopsis thaliana) mutants having alterations in seed germination. Auxin has also been implicated in seed germination. However, how auxin influences germination is largely unknown. Here, we demonstrate that auxin is linked via the IAA30 gene with a salt signaling cascade mediated by the NAM-ATAF1/2-CUC2 transcription factor NTM2/Arabidopsis NAC domain-containing protein 69 (for NAC with Transmembrane Motif1) during seed germination. Germination of the NTM2-deficient ntm2-1 mutant seeds exhibited enhanced resistance to high salinity. However, the salt resistance disappeared in the ntm2-1 mutant overexpressing the IAA30 gene, which was induced by salt in a NTM2-dependent manner. Auxin exhibited no discernible effects on germination under normal growth conditions. Under high salinity, however, whereas exogenous application of auxin further suppressed the germination of control seeds, the auxin effects were reduced in the ntm2-1 mutant. Consistent with the inhibitory effects of auxin on germination, germination of YUCCA 3-overexpressing plants containing elevated levels of active auxin was more severely influenced by salt. These observations indicate that auxin delays seed germination under high salinity through cross talk with the NTM2-mediated salt signaling in Arabidopsis. PMID:21450938

Seed after-ripening and dormancy determine adult life history independently of germination timing.

PubMed

de Casas, Rafael Rubio; Kovach, Katherine; Dittmar, Emily; Barua, Deepak; Barco, Brenden; Donohue, Kathleen

2012-05-01

• Seed dormancy can affect life history through its effects on germination time. Here, we investigate its influence on life history beyond the timing of germination. • We used the response of Arabidopsis thaliana to chilling at the germination and flowering stages to test the following: how seed dormancy affects germination responses to the environment; whether variation in dormancy affects adult phenology independently of germination time; and whether environmental cues experienced by dormant seeds have an effect on adult life history. • Dormancy conditioned the germination response to low temperatures, such that prolonged periods of chilling induced dormancy in nondormant seeds, but stimulated germination in dormant seeds. The alleviation of dormancy through after-ripening was associated with earlier flowering, independent of germination date. Experimental dormancy manipulations showed that prolonged chilling at the seed stage always induced earlier flowering, regardless of seed dormancy. Surprisingly, this effect of seed chilling on flowering time was observed even when low temperatures did not induce germination. • In summary, seed dormancy influences flowering time and hence life history independent of its effects on germination timing. We conclude that the seed stage has a pronounced effect on life history, the influence of which goes well beyond the timing of germination. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Microbiologic factors affecting Clostridium difficile recurrence.

PubMed

Chilton, C H; Pickering, D S; Freeman, J

2018-05-01

Recurrent Clostridium difficile infection (rCDI) places a huge economic and practical burden on healthcare facilities. Furthermore, rCDI may affect quality of life, leaving patients in an rCDI cycle and dependant on antibiotic therapy. To discuss the importance of microbiologic factors in the development of rCDI. Literature was drawn from a search of PubMed from 2000 onwards with the search term 'recurrent Clostridium difficile infection' and further references cited within these articles. Meta-analyses and systematic reviews have shown that CDI and rCDI risk factors are similar. Development of rCDI is attendant on many factors, including immune status or function, comorbidities and concomitant treatments. Studies suggest that poor bacterial diversity is correlated with clinical rCDI. Narrow-spectrum gut microflora-sparing antimicrobials (e.g. surotomycin, cadazolid, ridinilazole) are in development for CDI treatment, while microbiota therapeutics (faecal microbiota transplantation, nontoxigenic C. difficile, stool substitutes) are increasingly being explored. rCDI can only occur when viable C. difficile spores are present, either within the gut lumen after infection or when reacquired from the environment. C. difficile spore germination can be influenced by gut environmental factors resulting from dysbiosis, and spore outgrowth may be affected stage by some antimicrobials (e.g. fidaxomicin, ramoplanin, oritavancin). rCDI is a significant challenge for healthcare professionals, requiring a multifaceted approach; optimized infection control to minimize reinfection; C. difficile-targeted antibiotics to minimize dysbiosis; and gut microflora restoration to promote colonization resistance. These elements should be informed by our understanding of the microbiologic factors involved in both C. difficile itself and the gut microbiome. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Analysis of how ant behaviors affect germination in a tropical myrmecochore Calathea microcephala (P. & E.) Koernicke (Marantaceae): Microsite selection and aril removal by neotropical ants, Odontomachus, Pachycondyla, and Solenopsis (Formicidae).

PubMed

Horvitz, C C

1981-10-01

The evolutionary effects of a tropical ant-seed interaction are examined by posing questions about the fate of Calathea seeds carried by neotropical ants. Where do ants take seeds and what do they do with them? How do ant behaviors affect seed germination? Treatment of seeds by ants is determined by a series of seed-fate trials in captive colonies. There is no evidence of seed predation by ants. Odontomachus laticeps, Pachycondyla spp, and Solenopsis geminata rapidly displace seeds to ant nests, determine the microsites of seeds, and remove the seed arils for food. The seed arils are rich in lipids. The effects on germination of microsite selection and aril removal are quantitatively evaluated. Seeds which are immediately taken to a consistently moist spot germinate readily; 72% germinate, with a mean germination speed of 29 days. For such seeds aril removal does not significantly affect germination. In contrast, seeds which experience a delay before encountering appropriate germination conditions seem to exhibit an induced dormancy (sensu, Harper 1977) and a lower germination percentage. They take longer to germinate (up to 85 days) even after conditions become appropriate. It appears that their germination is enhanced by aril removal, which may act as an environmental cue to break dormancy. Such a mechanism would indicate that ant-handling of seeds is predictive of favorable conditions for seedling growth and establishment. The exact nature of such conditions and the effects on plant population dynamics remain to be seen.

The role of the Arabidopsis FUSCA3 transcription factor during inhibition of seed germination at high temperature

PubMed Central

2012-01-01

Background Imbibed seeds integrate environmental and endogenous signals to break dormancy and initiate growth under optimal conditions. Seed maturation plays an important role in determining the survival of germinating seeds, for example one of the roles of dormancy is to stagger germination to prevent mass growth under suboptimal conditions. The B3-domain transcription factor FUSCA3 (FUS3) is a master regulator of seed development and an important node in hormonal interaction networks in Arabidopsis thaliana. Its function has been mainly characterized during embryonic development, where FUS3 is highly expressed to promote seed maturation and dormancy by regulating ABA/GA levels. Results In this study, we present evidence for a role of FUS3 in delaying seed germination at supraoptimal temperatures that would be lethal for the developing seedlings. During seed imbibition at supraoptimal temperature, the FUS3 promoter is reactivated and induces de novo synthesis of FUS3 mRNA, followed by FUS3 protein accumulation. Genetic analysis shows that FUS3 contributes to the delay of seed germination at high temperature. Unlike WT, seeds overexpressing FUS3 (ML1:FUS3-GFP) during imbibition are hypersensitive to high temperature and do not germinate, however, they can fully germinate after recovery at control temperature reaching 90% seedling survival. ML1:FUS3-GFP hypersensitivity to high temperature can be partly recovered in the presence of fluridone, an inhibitor of ABA biosynthesis, suggesting this hypersensitivity is due in part to higher ABA level in this mutant. Transcriptomic analysis shows that WT seeds imbibed at supraoptimal temperature activate seed-specific genes and ABA biosynthetic and signaling genes, while inhibiting genes that promote germination and growth, such as GA biosynthetic and signaling genes. Conclusion In this study, we have uncovered a novel function for the master regulator of seed maturation, FUS3, in delaying germination at supraoptimal

Temperatures during flower bud development affect pollen germination, self-incompatibility reaction and early fruit development of clementine (Citrus clementina Hort. ex Tan.).

PubMed

Distefano, G; Gentile, A; Hedhly, A; La Malfa, S

2018-03-01

One of the key environmental factors affecting plant reproductive systems is temperature. Characterising such effects is especially relevant for some commercially important genera such as Citrus. In this genus, failure of fertilisation results in parthenocarpic fruit development and seedlessness, which is a much-prized character. Here, we characterise the effects of temperature on flower and ovary development, and on pollen-pistil interactions in 'Comune' clementine (Citrus clementina Hort. ex Tan.). We examine flower bud development, in vitro pollen germination and pollen-pistil interaction at different temperatures (15, 20, 25 or 30 °C). These temperatures span the range from 'cold' to 'hot' weather during the flowering season in many citrus-growing regions. Temperature had a strong effect on flower and ovary development, pollen germination, and pollen tube growth kinetics. In particular, parthenocarpic fruit development (indicated by juice vesicle growth) was initiated early if flowers were exposed to warmer temperatures during anthesis. Exposure to different temperatures during flower bud development also alters expression of the self-incompatibility reaction. This affects the point in the pistil at which pollen tube growth is arrested and confirms the role of sub- and supra-optimal temperatures in determining the numbers of pollen tubes reaching the ovary. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Functional analysis of a biosynthetic cluster essential for production of 4-formylaminooxyvinylglycine, a germination-arrest factor from Pseudomonas fluorescens WH6

USDA-ARS?s Scientific Manuscript database

Rhizosphere-associated Pseudomonas fluorescens WH6 produces the germination-arrest factor, 4-formylaminooxyvinylglycine (FVG). FVG has previously been shown to both arrest the germination of weedy grasses and to inhibit the growth of the bacterial plant pathogen Erwinia amylovora. Very little is kno...

The effects of flooding and sedimentation on seed germination of two bottomland hardwood tree species

USGS Publications Warehouse

Pierce, Aaron R.; King, S.L.

2007-01-01

Flooding and sedimentation are two of the dominant disturbances that influence tree species composition and succession in floodplain forests. The importance of these disturbances may be most notable during the germination and establishment phases of plant succession. Channelization of most alluvial systems in the southeastern United States has caused dramatic and systematic alterations to both hydrologic and sedimentation processes of floodplain systems. We determined the influence of these altered abiotic processes on the germination and growth of two common floodplain tree species: swamp chestnut oak (Quercus michauxii Nutt.) and overcup oak (Q. lyrata Walt.). Flood durations of 0 days, 15 days, and 30 days prior to germination was a factor in germination, but the effect varied by species. For instance, ovcrcup oak, which has a higher tolerance to flooding than swamp chestnut oak, had higher germination rates in the flooded treatments (15-day x?? = 78% and 30-day x?? = 85%) compared to the non-flooded treatment (x?? = 54%). In contrast, germination rates of swamp chestnut oak were negatively affected by the 30-day flood treatment. Sediment deposition rates of 2 cm of top soil, 2 cm of sand, and 8 cm of sand also affected germination, but were secondary to flood duration. The main effect of the sediment treatment in this experiment was a reduction in above-ground height of seedlings. Our study provides evidence for the importance of both flooding and sedimentation in determining tree species composition in floodplain systems, and that tolerance levels to such stressors vary by species. ?? 2007, The Society of Wetland Scientists.

Oxygen requirement of germinating flax seeds

NASA Astrophysics Data System (ADS)

Kuznetsov, Oleg A.; Hasenstein, K. H.

2003-05-01

Plant experiments in earth orbit are typically prepared on the ground and germinated in orbit to study gravity effects on the developing seedlings. Germination requires the breakdown of storage compounds, and this metabolism depends upon respiration, making oxygen one of the limiting factors in seed germination. In microgravity lack of run-off of excess water requires careful testing of water dispensation and oxygen availability. In preparation for a shuttle experiment (MICRO on STS-107) we studied germination and growth of flax ( Linum usitatissimum L.) seedlings in the developed hardware (Magnetic Field Chamber, MFC). We tested between four to 32 seeds per chamber (air volume = 14 mL) and after 36 h measured the root length. At 90 μl O 2 per seed (32 seeds/chamber), the germination decreased from 94 to 69%, and the root length was reduced by 20%, compared to 8 seeds per chamber. Based on the percent germination and root length obtained in controlled gas mixtures between 3.6 and 21.6% O 2 we determined the lower limit of reliable germination to be 10 vol. % O 2 at atmospheric pressure. Although the oxygen available in the MFC's can support the intended number of seeds, the data show that seed storage and microgravity-related limitations may reduce germination.

The role of the Arabidopsis FUSCA3 transcription factor during inhibition of seed germination at high temperature.

PubMed

Chiu, Rex S; Nahal, Hardeep; Provart, Nicholas J; Gazzarrini, Sonia

2012-01-27

Imbibed seeds integrate environmental and endogenous signals to break dormancy and initiate growth under optimal conditions. Seed maturation plays an important role in determining the survival of germinating seeds, for example one of the roles of dormancy is to stagger germination to prevent mass growth under suboptimal conditions. The B3-domain transcription factor FUSCA3 (FUS3) is a master regulator of seed development and an important node in hormonal interaction networks in Arabidopsis thaliana. Its function has been mainly characterized during embryonic development, where FUS3 is highly expressed to promote seed maturation and dormancy by regulating ABA/GA levels. In this study, we present evidence for a role of FUS3 in delaying seed germination at supraoptimal temperatures that would be lethal for the developing seedlings. During seed imbibition at supraoptimal temperature, the FUS3 promoter is reactivated and induces de novo synthesis of FUS3 mRNA, followed by FUS3 protein accumulation. Genetic analysis shows that FUS3 contributes to the delay of seed germination at high temperature. Unlike WT, seeds overexpressing FUS3 (ML1:FUS3-GFP) during imbibition are hypersensitive to high temperature and do not germinate, however, they can fully germinate after recovery at control temperature reaching 90% seedling survival. ML1:FUS3-GFP hypersensitivity to high temperature can be partly recovered in the presence of fluridone, an inhibitor of ABA biosynthesis, suggesting this hypersensitivity is due in part to higher ABA level in this mutant. Transcriptomic analysis shows that WT seeds imbibed at supraoptimal temperature activate seed-specific genes and ABA biosynthetic and signaling genes, while inhibiting genes that promote germination and growth, such as GA biosynthetic and signaling genes. In this study, we have uncovered a novel function for the master regulator of seed maturation, FUS3, in delaying germination at supraoptimal temperature. Physiologically, this is

Intra-specific downsizing of frugivores affects seed germination of fleshy-fruited plant species

NASA Astrophysics Data System (ADS)

Pérez-Méndez, Néstor; Rodríguez, Airam; Nogales, Manuel

2018-01-01

The loss of largest-bodied individuals within species of frugivorous animals is one of the major consequences of defaunation. The gradual disappearance of large-bodied frugivores is expected to entail a parallel deterioration in seed dispersal functionality if the remaining smaller-sized individuals are not so effective as seed dispersers. While the multiple impacts of the extinction of large bodied species have been relatively well studied, the impact of intraspecific downsizing (i.e. the extinction of large individuals within species) on seed dispersal has rarely been evaluated. Here we experimentally assessed the impact of body-size reduction in the frugivorous lizard Gallotia galloti (Lacertidae), an endemic species of the Canary Islands, on the seed germination patterns of two fleshy-fruited plant species (Rubia fruticosa and Withania aristata). Seed germination curves and the proportions of germinated seeds were compared for both plant species after being defecated by large-sized individuals and small-sized individuals. The data show that seeds of W. aristata defecated by larger-sized lizards germinated faster and in a higher percentage than those defecated by small-sized lizards, while no differences were found for R. fruticosa seeds. Our results suggest that disappearance of the largest individuals of frugivorous species may impair recruitment of some plant species by worsening seed germination. They also warn us of a potential cryptic loss of seed dispersal functionality on defaunated ecosystems, even when frugivorous species remain abundant.

Nitrate affects sensu-stricto germination of after-ripened Sisymbrium officinale seeds by modifying expression of SoNCED5, SoCYP707A2 and SoGA3ox2 genes.

PubMed

Carrillo-Barral, Néstor; Matilla, Angel J; Rodríguez-Gacio, María del Carmen; Iglesias-Fernández, Raquel

2014-03-01

The influence of nitrate upon the germination of Sisymbrium officinale seeds is not entirely controlled by after-ripening (AR), a process clearly influenced by nitrate. Recently, we have reported that nitrate affects sensu-stricto germination of non-AR (AR0) seeds by modifying the expression of crucial genes involved in the metabolism of GA and ABA. In this study, we demonstrate that nitrate affects also the germination of AR seeds because: (i) the AR negatively alters the ABA sensitivity being the seed more ABA-sensible as the AR is farthest from optimal (AR0 and AR20 versus AR7); in the presence of diniconazole (DZ), a competitive inhibitor of ABA 8'-hydroxylase, testa rupture is affected while the endosperm rupture is not. (ii) AR7 seed-coat rupture is not inhibited by paclobutrazol (PBZ) suggesting that nitrate can act by a mechanism GA-independent. (iii) The germination process is accelerated by nitrate, most probably by the increase in the expression of SoNCED5, SoCYP707A2 and SoGA3ox2 genes. Taken together, these and previous results demonstrate that nitrate promotes germination of AR and non-AR seeds through transcriptional changes of different genes involved in ABA and GA metabolism. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Factors Governing the Germination of Sulfate-Reducing Desulfotomaculum Endospores Involved in Oil Reservoir Souring.

NASA Astrophysics Data System (ADS)

Sherry, A.; Bell, E.; Cueto, G.; Suarez-Suarez, A.; Pilloni, G.; Hubert, C. R.

2015-12-01

Reservoir souring is caused by the activity of sulfate-reducing microorganisms (SRM) in subsurface oil reservoirs, and is often induced by seawater injection during secondary oil recovery. Souring can potentially contribute to corrosion of infrastructure, health and safety hazards to the workforce, and reduction in value by increasing refining costs associated with producing the oil resource. Souring causes annual losses in the billions of dollars to the oil industry. Endospore-forming SRM, such as Desulfotomaculum spp., are often suspected culprits in reservoir souring. Endospores can survive unfavourable conditions for long periods, yet remain poised to germinate and become active if conditions become more favourable. Factors governing endospore germination are poorly understood, but are thought to include availability of nutrients, possibly metabolic by products of other anaerobic bioprocesses, and/or variations in temperature. Most research has focused on aerobic Bacillus spp., with very few studies dedicated to spore germination among anaerobes (order Clostridiales) including the sulfate-reducing Desulfotomaculum found in anoxic subsurface petroleum reservoirs. For Desulfotomaculum spores in deep hot oil reservoirs, cold seawater introduction during secondary oil recovery may create thermal viability zones for sulfate reduction near the injection wellbore. To evaluate these processes, sulfate-containing microcosms were prepared with different marine sediments as a source of spores, and amended with organic substrates in the presence or absence of oil. Incubation at 80°C for six days was followed by a down-shift in temperature to 60°C to mimic cold seawater injection into a hot reservoir. Souring did not occur at 80°C, but commenced within hours at 60°C. Microcosms were monitored for sulfate reduction and organic acids in combination with next generation sequencing of 16S rRNA genes (Ion Torrent, Illumina MiSeq). Through a combination of high

Oxygen requirement of germinating flax seeds.

PubMed

Kuznetsov, Oleg A; Hasenstein, K H

2003-01-01

Plant experiments in earth orbit are typically prepared on the ground and germinated in orbit to study gravity effects on the developing seedlings. Germination requires the breakdown of storage compounds, and this metabolism depends upon respiration, making oxygen one of the limiting factors in seed germination. In microgravity lack of run-off of excess water requires careful testing of water dispensation and oxygen availability. In preparation for a shuttle experiment (MICRO on STS-107) we studied germination and growth of flax (Linum usitatissimum L.) seedlings in the developed hardware (Magnetic Field Chamber, MFC). We tested between four to 32 seeds per chamber (air volume=14 mL) and after 36 h measured the root length. At 90 microliters O2 per seed (32 seeds/chamber), the germination decreased from 94 to 69%, and the root length was reduced by 20%, compared to 8 seeds per chamber. Based on the percent germination and root length obtained in controlled gas mixtures between 3.6 and 21.6% O2 we determined the lower limit of reliable germination to be 10 vol. % O2 at atmospheric pressure. Although the oxygen available in the MFC's can support the intended number of seeds, the data show that seed storage and microgravity-related limitations may reduce germination. c2003 Published by Elsevier Ltd on behalf of COSPAR.

Oxygen requirement of germinating flax seeds

NASA Technical Reports Server (NTRS)

Kuznetsov, Oleg A.; Hasenstein, K. H.; Hasentein, K. H. (Principal Investigator)

2003-01-01

Plant experiments in earth orbit are typically prepared on the ground and germinated in orbit to study gravity effects on the developing seedlings. Germination requires the breakdown of storage compounds, and this metabolism depends upon respiration, making oxygen one of the limiting factors in seed germination. In microgravity lack of run-off of excess water requires careful testing of water dispensation and oxygen availability. In preparation for a shuttle experiment (MICRO on STS-107) we studied germination and growth of flax (Linum usitatissimum L.) seedlings in the developed hardware (Magnetic Field Chamber, MFC). We tested between four to 32 seeds per chamber (air volume=14 mL) and after 36 h measured the root length. At 90 microliters O2 per seed (32 seeds/chamber), the germination decreased from 94 to 69%, and the root length was reduced by 20%, compared to 8 seeds per chamber. Based on the percent germination and root length obtained in controlled gas mixtures between 3.6 and 21.6% O2 we determined the lower limit of reliable germination to be 10 vol. % O2 at atmospheric pressure. Although the oxygen available in the MFC's can support the intended number of seeds, the data show that seed storage and microgravity-related limitations may reduce germination. c2003 Published by Elsevier Ltd on behalf of COSPAR.

Seed germination of three Ulmus species from Turkey as influenced by temperature and light.

PubMed

Cicek, Emrah; Tilki, Fahrettin

2007-04-01

The effect of temperature and light on the germination performance of Ulmus minor, Ulmus glabra and Ulmus laevis were studied in this research. Seeds were germinated under constant temperatures of 20 and 25 degrees C and alternating temperatures of 25/15 and 30/20 degrees C. Within each temperature regime, seeds were subjected daily to the following photoperiods: total darkness and 8 hr photoperiod. Temperature and light affected seed germination percentage (GP) and germination rate expressed as peak value (PV) in Ulmus minor and 25 and 30/20 degrees C under light gave the highest GP (>95%) and PV (>23). The temperatures of 25/15 and 30/20 degrees C gave the highest GP (>89%) in Ulmus glabra and light did not significantly affect GP. But the highest PV in Ulmus glabra was found at these temperatures under light. Germination percentage of Ulmus laevis was not affected by temperature and light, but the alternating temperature of 30/20 degrees C produced the highest germination rate under darkness.

Seedling Vigor in Beta vulgaris: The Artistry of Germination

USDA-ARS?s Scientific Manuscript database

Seedling vigor and stand establishment are two problems that growers have struggled with for decades. The initial conditions that a germinating seed encounters, and its ability to deal with them, affect the rate at which germination occurs, the rate of mobilization of stored energy reserves that the...

Smoke-induced seed germination in California chaparral

USGS Publications Warehouse

Keeley, J.E.; Fotheringham, C.J.

1998-01-01

smoke. While the mechanism behind smoke-induced germination is not known, it appears that smoke may be involved in overcoming different blocks to germination in different species. For example, in Emmenanthe penduliflora, NO2 in smoke was sufficient to induce germination, and most forms of physical or chemical scarification also induced germination. For Romneya coulteri, NO2 alone failed to induce germination, and scarified seeds required addition of gibberellic acid. In Dicentra chrysantha, none of these treatments, nor smoke alone, induced germination, but germination was triggered by a combination of soil burial followed by smoke treatment. Smoke-stimulated species differed substantially in the duration of smoke exposure required to induce germination, and this was inversely correlated with tolerance to smoke exposure. We suggest that such differences in response may affect postfire community structure.

Effects of arbuscular mycorrhizal fungi and maternal plant sex on seed germination and early plant establishment.

PubMed

Varga, Sandra

2015-03-01

• Arbuscular mycorrhizal fungi usually enhance overall plant performance, yet their effects on seed germination and early plant establishment, crucial steps in plant cycles, are generally overlooked. In gynodioecious species, sexual dimorphism in these traits has been reported, with females producing seeds that germinate at a faster rate than seeds from hermaphrodites.• Using the gynodioecious plant Geranium sylvaticum, I investigated in a greenhouse experiment whether the presence of arbuscular mycorrhizal spores affects seed germination and early plant establishment, examining at the same time whether the sex of the mother producing the seeds also influences these parameters and whether sex-specific interactions between these two factors exist.• The presence of arbuscular mycorrhizal spores in the soil decreased seed germination, did not affect plant survival, but did increase plant growth. Moreover, no significant differences in seed traits were detected between the sexes of the plants producing the seeds.• This study demonstrates that arbuscular mycorrhizal fungi may have contrasting effects for plants during early life stages and that mycorrhizal effects can take place even at the precolonization stage. © 2015 Botanical Society of America, Inc.

Bryophyte spore germinability is inhibited by peatland substrates

NASA Astrophysics Data System (ADS)

Bu, Zhao-Jun; Li, Zhi; Liu, Li-Jie; Sundberg, Sebastian; Feng, Ya-Min; Yang, Yun-He; Liu, Shuang; Song, Xue; Zhang, Xing-Lin

2017-01-01

Bryophyte substrates and species may affect spore germination through allelopathy. Polytrichum strictum is currently expanding in peatlands in north-eastern China - is this an effect of its superior spore germinability or do its gametophytes have a stronger allelopathic effect than do Sphagnum? We conducted a spore burial experiment to test the effect of species identity, substrate and water table depth (WTD) on spore germinability and bryophyte allelopathic effect with P. strictum and two Sphagnum species (S. palustre and S. magellanicum). After 5 months of burial during a growing season, the spores were tested for germinability. Allelopathic effect of bryophyte substrates was assessed by the difference between spore germinability after being stored inside or outside the substrates. After burial, more than 90% of the spores lost their germinability across all three species due to ageing and allelopathy. Spore germinability differed among species, where the spores in S. palustre had a higher germination frequency than those in P. strictum. The three bryophytes maintained a higher germinability in Sphagnum than in Polytrichum hummocks, probably due to a stronger allelopathic effect of P. strictum. Water table drawdown by 10 cm increased germinability by more than 60% across the three species. The study indicates that P. strictum does not possess an advantage regarding spore germination but rather its gametophytes have a stronger allelopathic effect. Due to the weaker inhibitive effect of Sphagnum gametophytes, P. strictum may have a potential establishment superiority over Sphagnum in peatlands, in addition to a better drought tolerance, which may explain its current expansion.

QTL Mapping of Low-Temperature Germination Ability in the Maize IBM Syn4 RIL Population

PubMed Central

Hu, Shuaidong; Lübberstedt, Thomas; Zhao, Guangwu; Lee, Michael

2016-01-01

Low temperature is the primary factor to affect maize sowing in early spring. It is, therefore, vital for maize breeding programs to improve tolerance to low temperatures at seed germination stage. However, little is known about maize QTL involved in low-temperature germination ability. 243 lines of the intermated B73×Mo17 (IBM) Syn4 recombinant inbred line (RIL) population was used for QTL analysis of low-temperature germination ability. There were significant differences in germination-related traits under both conditions of low temperature (12°C/16h, 18°C/8h) and optimum temperature (28°C/24h) between the parental lines. Only three QTL were identified for controlling optimum-temperature germination rate. Six QTL controlling low-temperature germination rate were detected on chromosome 4, 5, 6, 7 and 9, and contribution rate of single QTL explained between 3.39%~11.29%. In addition, six QTL controlling low-temperature primary root length were detected in chromosome 4, 5, 6, and 9, and the contribution rate of single QTL explained between 3.96%~8.41%. Four pairs of QTL were located at the same chromosome position and together controlled germination rate and primary root length under low temperature condition. The nearest markers apart from the corresponding QTL (only 0.01 cM) were umc1303 (265.1 cM) on chromosome 4, umc1 (246.4 cM) on chromosome 5, umc62 (459.1 cM) on chromosome 6, bnl14.28a (477.4 cM) on chromosome 9, respectively. A total of 3155 candidate genes were extracted from nine separate intervals based on the Maize Genetics and Genomics Database (http://www.maizegdb.org). Five candidate genes were selected for analysis as candidates putatively affecting seed germination and seedling growth at low temperature. The results provided a basis for further fine mapping, molecular marker assisted breeding and functional study of cold-tolerance at the stage of seed germination in maize. PMID:27031623

Effects of High Pressure on Bacillus licheniformis Spore Germination and Inactivation

PubMed Central

Borch-Pedersen, Kristina; Mellegård, Hilde; Reineke, Kai; Boysen, Preben; Sevenich, Robert; Lindbäck, Toril

2017-01-01

ABSTRACT Bacillus and Clostridium species form spores, which pose a challenge to the food industry due to their ubiquitous nature and extreme resistance. Pressurization at <300 MPa triggers spore germination by activating germination receptors (GRs), while pressurization at >300 MPa likely triggers germination by opening dipicolinic acid (DPA) channels present in the inner membrane of the spores. In this work, we expose spores of Bacillus licheniformis, a species associated with food spoilage and occasionally with food poisoning, to high pressure (HP) for holding times of up to 2 h. By using mutant spores lacking one or several GRs, we dissect the roles of the GerA, Ynd, and GerK GRs in moderately HP (mHP; 150 MPa)-induced spore germination. We show that Ynd alone is sufficient for efficient mHP-induced spore germination. GerK also triggers germination with mHP, although at a reduced germination rate compared to that of Ynd. GerA stimulates mHP-induced germination but only in the presence of either the intact GerK or Ynd GR. These results suggests that the effectiveness of the individual GRs in mHP-induced germination differs from their effectiveness in nutrient-induced germination, where GerA plays an essential role. In contrast to Bacillus subtilis spores, treatment with very HP (vHP) of 550 MPa at 37°C did not promote effective germination of B. licheniformis spores. However, treatment with vHP in combination with elevated temperatures (60°C) gave a synergistic effect on spore germination and inactivation. Together, these results provide novel insights into how HP affects B. licheniformis spore germination and inactivation and the role of individual GRs in this process. IMPORTANCE Bacterial spores are inherently resistant to food-processing regimes, such as high-temperature short-time pasteurization, and may therefore compromise food durability and safety. The induction of spore germination facilitates subsequent inactivation by gentler processing conditions

Seed storage conditions change the germination pattern of clonal growth plants in Mediterranean salt marshes

USGS Publications Warehouse

Espinar, J.L.; Garcia, L.V.; Clemente, L.

2005-01-01

The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three saltmarsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable conditions for germination were restored. Tolerance of the germination process was related to the average salinity level measured during the growth/germination season at sites where established individuals of each species dominated the species cover. No relationship was found between salinity tolerance of the germination process and seed response to extended exposure to flooding and salinity conditions. The salinity response was significantly related to the conditions prevailing in the habitats of the respective species during the unfavorable (nongrowth/nongermination) season. Our results indicate that changes in salinity and hydrology while seeds are dormant affect the outcome of the seed-bank response, even when conditions at germination are identical. Because these environmental-history-dependent responses differentially affect seed germination, seedling density, and probably sexual recruitment in the studied and related species, these influences should be considered for wetland restoration and management.

Mitochondrial AtTrxo1 is transcriptionally regulated by AtbZIP9 and AtAZF2 and affects seed germination under saline conditions

PubMed Central

Ortiz-Espín, Ana; Iglesias-Fernández, Raquel; Calderón, Aingeru; Carbonero, Pilar; Sevilla, Francisca

2017-01-01

Abstract Mitochondrial thioredoxin-o (AtTrxo1) was characterized and its expression examined in different organs of Arabidopsis thaliana. AtTrxo1 transcript levels were particularly high in dry seeds and cotyledons where they reached a maximum 36 h after imbibition with water, coinciding with 50% germination. Expression was lower in seeds germinating in 100 mM NaCl. To gain insight into the transcriptional regulation of the AtTrxo1 gene, a phylogenomic analysis was coupled with the screening of an arrayed library of Arabidopsis transcription factors in yeast. The basic leucine zipper AtbZIP9 and the zinc finger protein AZF2 were identified as putative transcriptional regulators. Transcript regulation of AtbZIP9 and AtAFZ2 during germination was compatible with the proposed role in transcriptional regulation of AtTrxo1. Transient over-expression of AtbZIP9 and AtAZF2 in Nicotiana benthamiana leaves demonstrated an activation effect of AtbZIP9 and a repressor effect of AtAZF2 on AtTrxo1 promoter-driven reporter expression. Although moderate concentrations of salt delayed germination in Arabidopsis wild-type seeds, those of two different AtTrxo1 knock-out mutants germinated faster and accumulated higher H2O2 levels than the wild-type. All these data indicate that AtTrxo1 has a role in redox homeostasis during seed germination under salt conditions. PMID:28184497

The effects of achene type and germination time on plant performance in the heterocarpic Anacyclus clavatus (Asteraceae).

PubMed

Afonso, Ana; Castro, Sílvia; Loureiro, João; Mota, Lucie; Cerca de Oliveira, José; Torices, Rubén

2014-05-01

• In heterocarpy, fruits with different morphologies have been associated with alternative strategies of dispersal, germination, dormancy, and seedling competitive ability. In heterocarpic species, it is common to find fruits with competitive or dispersal syndromes. The competitive advantage of nondispersing fruits has been frequently attributed to their larger size, but recent studies have suggested that this could also be mediated by germination time. The main objective of our study was to investigate which factor, fruit type or germination time, most affects plant performance and, consequently, competitive ability, using the heterocarpic species Anacyclus clavatus• To explore the effects of achene type and germination time on plant performance, we followed an innovative experimental approach including two experiments: one allowing for differences in germination time, and the other evaluating the effect of achene type alone by synchronizing germination time.• A significant effect of germination time on several postdispersal life-history traits was observed: Achenes that germinated earlier produced plants with higher biomass and reproductive effort. When germination time was controlled, no significant differences were observed in any of the traits.• The competitive advantage of achenes with different morphologies was mainly mediated by germination time and not by differences in size or other intrinsic traits. The consequences of these results are discussed in light of the dispersal-competition trade-off. Our experimental approach (i.e., the synchronization of germination time) revealed the importance of manipulative experiments for testing the effects of germination time on plant survival and performance. © 2014 Botanical Society of America, Inc.

The Arabidopsis MYB96 Transcription Factor Is a Positive Regulator of ABSCISIC ACID-INSENSITIVE4 in the Control of Seed Germination1

PubMed Central

Lee, Kyounghee; Lee, Hong Gil; Kim, Hyun Uk; Seo, Pil Joon

2015-01-01

Seed germination is a key developmental transition that initiates the plant life cycle. The timing of germination is determined by the coordinated action of two phytohormones, gibberellin and abscisic acid (ABA). In particular, ABA plays a key role in integrating environmental information and inhibiting the germination process. The utilization of embryonic lipid reserves contributes to seed germination by acting as an energy source, and ABA suppresses lipid degradation to modulate the germination process. Here, we report that the ABA-responsive R2R3-type MYB transcription factor MYB96, which is highly expressed in embryo, regulates seed germination by controlling the expression of ABSCISIC ACID-INSENSITIVE4 (ABI4) in Arabidopsis (Arabidopsis thaliana). In the presence of ABA, germination was accelerated in MYB96-deficient myb96-1 seeds, whereas the process was significantly delayed in MYB96-overexpressing activation-tagging myb96-ox seeds. Consistently, myb96-1 seeds degraded a larger extent of lipid reserves even in the presence of ABA, while reduced lipid mobilization was observed in myb96-ox seeds. MYB96 directly regulates ABI4, which acts as a repressor of lipid breakdown, to define its spatial and temporal expression. Genetic analysis further demonstrated that ABI4 is epistatic to MYB96 in the control of seed germination. Taken together, the MYB96-ABI4 module regulates lipid mobilization specifically in the embryo to ensure proper seed germination under suboptimal conditions. PMID:25869652

Identification of Vigor Related Transcripts in Beta vulgaris When Germinated Under Abiotic Stress

USDA-ARS?s Scientific Manuscript database

Germination is the first opportunity to evaluate vigor for beet breeders. The initial condition a germinating seed encounters affects the speed and success of germination, the amount of stored energy reserves to withstand future stress, and the overall ability of the seedling to flourish. However, s...

Environmental factors for germination of Sclerotinia sclerotiorum sclerotia

USDA-ARS?s Scientific Manuscript database

Basal stalk rot of sunflower is an economically important and rather unique disease among crops that are susceptible to Sclerotinia sclerotiorum. This disease is the result of myceliogenic germination of sclerotia whereby the vegetative hyphae infect the sunflower below the soil level. In contrast, ...

Photocontrol of germination in Amaranthus caudatus.

PubMed

Kendrick, R E; Frankland, B

1969-12-01

Germination of Amaranthus caudatus is inhibited by light, far-red being the most effective part of the spectrum. At temperatures of 25° and below there is a low final germination percentage under continuous far-red whereas above 25° there is only a delaying effect. In the presence of a saturating concentration of gibberellic acid (GA3) at 25° seeds germinate under continuous far-red although they are delayed. At 25° seeds exposed to 48 hr far-red fail to germinate when transferred to darkness. This induced dormancy can be broken by a single short exposure to red light given at any time after the far-red illumination. This effect of short red can be reversed by a subsequent short period of far-red indicating that the seeds are phytochrome controlled. Although most seeds have escaped from the reversing effect of short far-red after an intervening dark period of 5 hours, germination is greatly reduced by continuous far-red at this time. Results of exposing seeds to varying periods of far-red before and after dark imbibition are interpreted in terms of a continual production of phytochrome in its active P fr form and a requirement for P fr action over a long period of time. Effects of intermittent and continuous low intensity far-red on the inhibition of germination provides further evidence for a low energy photoreaction involving phytochrome. Effects on Germination Index of continuous illumination with various light sources maintaining different P fr /P total ratios have been investigated. The results suggest that the proportion of phytochrome in the P fr form is the most important factor in the regulation of germination. A scheme for the phytochrome control of germination in Amaranthus caudatus is presented and possible explanations for the dependence on P fr /P total ratio are discussed.

Elongator promotes germination and early post-germination growth.

PubMed

Woloszynska, Magdalena; Gagliardi, Olimpia; Vandenbussche, Filip; Van Lijsebettens, Mieke

2018-01-02

The Elongator complex interacts with RNA polymerase II and via histone acetylation and DNA demethylation facilitates epigenetically the transcription of genes involved in diverse processes in plants, including growth, development, and immune response. Recently, we have shown that the Elongator complex promotes hypocotyl elongation and photomorphogenesis in Arabidopsis thaliana by regulating the photomorphogenesis and growth-related gene network that converges on genes implicated in cell wall biogenesis and hormone signaling. Here, we report that germination in the elo mutant was delayed by 6 h in the dark when compared to the wild type in a time lapse and germination assay. A number of germination-correlated genes were down-regulated in the elo transcriptome, suggesting a transcriptional regulation by Elongator. We also show that the hypocotyl elongation defect observed in the elo mutants in darkness originates very early in the post-germination development and is independent from the germination delay.

Winery wastewater inhibits seed germination and vegetative growth of common crop species.

PubMed

Mosse, Kim P M; Patti, Antonio F; Christen, Evan W; Cavagnaro, Timothy R

2010-08-15

The ability to reuse winery wastewater would be of significant benefit to the wine industry, as it could potentially be a cost-effective method of wastewater management, whilst at the same time providing a valuable water resource. This study investigated the effects of different dilutions of a semi-synthetic winery wastewater on the growth and germination of four common crop species in a glasshouse study; barley (Hordeum vulgare), millet (Pennisetum glaucum), lucerne (Medicago sativa) and phalaris (Phalaris aquatica). The wastewater caused a significant delay in the germination of lucerne, millet and phalaris, although overall germination percentage of all species was not affected. Vegetative growth was significantly reduced in all species, with millet being the most severely affected. The germination index of barley correlated very highly (r(2)=0.99) with barley biomass, indicating that barley seed germination bioassays are highly relevant to plant growth, and therefore may be of use as a bioassay for winery wastewater toxicity. Copyright 2010 Elsevier B.V. All rights reserved.

Chickpea seeds germination rational parameters optimization

NASA Astrophysics Data System (ADS)

Safonova, Yu A.; Ivliev, M. N.; Lemeshkin, A. V.

2018-05-01

The paper presents the influence of chickpea seeds bioactivation parameters on their enzymatic activity experimental results. Optimal bioactivation process modes were obtained by regression-factor analysis: process temperature - 13.6 °C, process duration - 71.5 h. It was found that in the germination process, the proteolytic, amylolytic and lipolytic enzymes activity increased, and the urease enzyme activity is reduced. The dependences of enzyme activity on chickpea seeds germination conditions were obtained by mathematical processing of experimental data. The calculated data are in good agreement with the experimental ones. This confirms the optimization efficiency based on experiments mathematical planning in order to determine the enzymatic activity of chickpea seeds germination optimal parameters of bioactivated seeds.

Effect of atmospheric plasma treatment on seed germination of rice (Oryza sativa L.)

NASA Astrophysics Data System (ADS)

Penado, Keith Nealson M.; Mahinay, Christian Lorenz S.; Culaba, Ivan B.

2018-01-01

Multiple methods of improving plant development have been utilized over the past decades. Despite these improvements, there still exists a need for better planting methods due to the increasing population of a global community. Studies have reported that plasma treatment affects the growth and germination of a variety of plant species, including a multitude of grains which often takes the bulk in the diet of the average human being. This study explores the effect of atmospheric air plasma jet treatment on the seed germination of rice (Oryza sativa L.). The seeds were treated using an atmospheric air plasma jet for 1, 2, and 3 s. The effect of plasma exposure shows a reduction of trichomes on the surface of the seed. This caused a possible increase in wettability which significantly affected the seed germ length but did not affect the seed germination count after the germination period of 72 h.

Effect of saline water on seed germination and early seedling growth of the halophyte quinoa

PubMed Central

Panuccio, M. R.; Jacobsen, S. E.; Akhtar, S. S.; Muscolo, A.

2014-01-01

Salinization is increasing on a global scale, decreasing average yields for most major crop plants. Investigations into salt resistance have, unfortunately, mainly been focused on conventional crops, with few studies screening the potential of available halophytes as new crops. This study has been carried out to investigate the mechanisms used by quinoa, a facultative halophytic species, in order to cope with high salt levels at various stages of its development. Quinoa is regarded as one of the crops that might sustain food security in this century, grown primarily for its edible seeds with their high protein content and unique amino acid composition. Although the species has been described as a facultative halophyte, and its tolerance to salt stress has been investigated, its physiological and molecular responses to seawater (SW) and other salts have not been studied. We evaluated the effects of SW and different salts on seed germination, seedling emergence and the antioxidative pathway of quinoa. Seeds were germinated in Petri dishes and seedlings grown in pots with SW solutions (25, 50, 75 and 100 %) and NaCl, CaCl2, KCl and MgCl2 individually, at the concentrations in which they are present in SW. Our results demonstrated that all salts, at lower concentrations, increased the germination rate but not the germination percentages, compared with control (pure water). Conversely, seedlings were differently affected by treatments in respect to salt type and concentration. Growth parameters affected were root and shoot length, root morphology, fresh and dry weight, and water content. An efficient antioxidant mechanism was present in quinoa, activated by salts during germination and early seedling growth, as shown by the activities of antioxidant enzymes. Total antioxidant capacity was always higher under salt stress than in water. Moreover, osmotic and ionic stress factors had different degrees of influence on germination and development. PMID:25139769

The oxygen requirement of germinating flax seeds

NASA Astrophysics Data System (ADS)

Kuznetsov, O.; Hasenstein, K.

Experiments for earth orbit are typically prepared on the ground and often germinated in orbit in order to study gravity effects on developing seedlings. Germination requires the breakdown of storage compounds and respiration. In orbit the formation of a water layer around the seed may further limit oxygen availability. Therefore, the oxygen content of the available gas volume is one of the limiting factors for seed germination. In preparation for an upcoming shuttle experiment (MICRO on STS-107) we studied germination and growth of flax (Linum usitatissimum L.) seedlings in the developed hardware. We tested per seed chamber (gas volume = 14 mL, O2 = 2.9 mL) between 4 to 32 seeds glued to germination paper by 1% (w/v) gum guar. A lexan cover and a gasket hermetically sealed each of the eight chambers. For imbibition of the seeds a previously optimized amount of distilled water was dispensed through sealed inlets. The seedlings were allowed to grow for either 32 to 48 h on a clinostat or without microgravity simulation. Then their root length was measured. With 32 seeds per chamber, four times the intended number of seeds for the flight, the germination rate decreased from 94 to 69%, and the root length was reduced by 20%. Experiments on the germination and root length in controlled atmospheres (5, 10, 15 and 21% O2 ) suggest that germination and growth for two days requires about 200 :l of O (1 mL air) per seed. Our2 experiments correlate oxygen dependency from seed mass and germination temperature, and analyze accumulation of gaseous metabolites (supported by NASA grant NAG10-0190).

The orphan germinant receptor protein GerXAO (but not GerX3b) is essential for L-alanine induced germination in Clostridium botulinum Group II.

PubMed

Brunt, Jason; Carter, Andrew T; Pye, Hannah V; Peck, Michael W

2018-05-04

Clostridium botulinum is an anaerobic spore forming bacterium that produces the potent botulinum neurotoxin that causes a severe and fatal neuro-paralytic disease of humans and animals (botulism). C. botulinum Group II is a psychrotrophic saccharolytic bacterium that forms spores of moderate heat resistance and is a particular hazard in minimally heated chilled foods. Spore germination is a fundamental process that allows the spore to transition to a vegetative cell and typically involves a germinant receptor (GR) that responds to environmental signals. Analysis of C. botulinum Group II genomes shows they contain a single GR cluster (gerX3b), and an additional single gerA subunit (gerXAO). Spores of C. botulinum Group II strain Eklund 17B germinated in response to the addition of L-alanine, but did not germinate following the addition of exogenous Ca 2+ -DPA. Insertional inactivation experiments in this strain unexpectedly revealed that the orphan GR GerXAO is essential for L-alanine stimulated germination. GerX3bA and GerX3bC affected the germination rate but were unable to induce germination in the absence of GerXAO. No role could be identified for GerX3bB. This is the first study to identify the functional germination receptor of C. botulinum Group II.

Abscisic acid in the thermoinhibition of lettuce seed germination and enhancement of its catabolism by gibberellin.

PubMed

Gonai, Takeru; Kawahara, Shusuke; Tougou, Makoto; Satoh, Shigeru; Hashiba, Teruyoshi; Hirai, Nobuhiro; Kawaide, Hiroshi; Kamiya, Yuji; Yoshioka, Toshihito

2004-01-01

Germination of lettuce (Lactuca sativa L. cv. 'Grand Rapids') seeds was inhibited at high temperatures (thermoinhibition). Thermoinhibition at 28 degrees C was prevented by the application of fluridone, an inhibitor of abscisic acid (ABA) biosynthesis. At 33 degrees C, the sensitivity of the seeds to ABA increased, and fluridone on its own was no longer effective. However, a combined application of fluridone and gibberellic acid (GA3) was able to restore the germination. Exogenous GA3 lowered endogenous ABA content in the seeds, enhancing catabolism of ABA and export of the catabolites from the intact seeds. The fluridone application also decreased the ABA content. Consequently, the combined application of fluridone and GA3 decreased the ABA content to a sufficiently low level to allow germination at 33 degrees C. There was no significant temperature-dependent change in endogenous GA1 contents. It is concluded that ABA is an important factor in the regulation of thermoinhibition of lettuce seed germination, and that GA affects the temperature responsiveness of the seeds through ABA metabolism.

Modeling the germination kinetics of clostridium botulinum 56A spores as affected by temperature, pH, and sodium chloride.

PubMed

Chea, F P; Chen, Y; Montville, T J; Schaffner, D W

2000-08-01

The germination kinetics of proteolytic Clostridium botulinum 56A spores were modeled as a function of temperature (15, 22, 30 degrees C), pH (5.5, 6.0, 6.5), and sodium chloride (0.5, 2.0, 4.0%). Germination in brain heart infusion (BHI) broth was followed with phase-contrast microscopy. Data collected were used to develop the mathematical models. The germination kinetics expressed as cumulated fraction of germinated spores over time at each environmental condition were best described by an exponential distribution. Quadratic polynomial models were developed by regression analysis to describe the exponential parameter (time to 63% germination) (r2 = 0.982) and the germination extent (r2 = 0.867) as a function of temperature, pH, and sodium chloride. Validation experiments in BHI broth (pH: 5.75, 6.25; NaCl: 1.0, 3.0%; temperature: 18, 26 degrees C) confirmed that the model's predictions were within an acceptable range compared to the experimental results and were fail-safe in most cases.

Germination and seedling establishment in orchids: a complex of requirements

PubMed Central

Rasmussen, Hanne N.; Dixon, Kingsley W.; Jersáková, Jana; Těšitelová, Tamara

2015-01-01

Background Seedling recruitment is essential to the sustainability of any plant population. Due to the minute nature of seeds and early-stage seedlings, orchid germination in situ was for a long time practically impossible to observe, creating an obstacle towards understanding seedling site requirements and fluctuations in orchid populations. The introduction of seed packet techniques for sowing and retrieval in natural sites has brought with it important insights, but many aspects of orchid seed and germination biology remain largely unexplored. Key Considerations The germination niche for orchids is extremely complex, because it is defined by requirements not only for seed lodging and germination, but also for presence of a fungal host and its substrate. A mycobiont that the seedling can parasitize is considered an essential element, and a great diversity of Basidiomycota and Ascomycota have now been identified for their role in orchid seed germination, with fungi identifiable as imperfect Rhizoctonia species predominating. Specificity patterns vary from orchid species employing a single fungal lineage to species associating individually with a limited selection of distantly related fungi. A suitable organic carbon source for the mycobiont constitutes another key requirement. Orchid germination also relies on factors that generally influence the success of plant seeds, both abiotic, such as light/shade, moisture, substrate chemistry and texture, and biotic, such as competitors and antagonists. Complexity is furthermore increased when these factors influence seeds/seedling, fungi and fungal substrate differentially. Conclusions A better understanding of germination and seedling establishment is needed for conservation of orchid populations. Due to the obligate association with a mycobiont, the germination niches in orchid species are extremely complex and varied. Microsites suitable for germination can be small and transient, and direct observation is difficult

Different Modes of Hydrogen Peroxide Action During Seed Germination

PubMed Central

Wojtyla, Łukasz; Lechowska, Katarzyna; Kubala, Szymon; Garnczarska, Małgorzata

2016-01-01

Hydrogen peroxide was initially recognized as a toxic molecule that causes damage at different levels of cell organization and thus losses in cell viability. From the 1990s, the role of hydrogen peroxide as a signaling molecule in plants has also been discussed. The beneficial role of H2O2 as a central hub integrating signaling network in response to biotic and abiotic stress and during developmental processes is now well established. Seed germination is the most pivotal phase of the plant life cycle, affecting plant growth and productivity. The function of hydrogen peroxide in seed germination and seed aging has been illustrated in numerous studies; however, the exact role of this molecule remains unknown. This review evaluates evidence that shows that H2O2 functions as a signaling molecule in seed physiology in accordance with the known biology and biochemistry of H2O2. The importance of crosstalk between hydrogen peroxide and a number of signaling molecules, including plant phytohormones such as abscisic acid, gibberellins, and ethylene, and reactive molecules such as nitric oxide and hydrogen sulfide acting on cell communication and signaling during seed germination, is highlighted. The current study also focuses on the detrimental effects of H2O2 on seed biology, i.e., seed aging that leads to a loss of germination efficiency. The dual nature of hydrogen peroxide as a toxic molecule on one hand and as a signal molecule on the other is made possible through the precise spatial and temporal control of its production and degradation. Levels of hydrogen peroxide in germinating seeds and young seedlings can be modulated via pre-sowing seed priming/conditioning. This rather simple method is shown to be a valuable tool for improving seed quality and for enhancing seed stress tolerance during post-priming germination. In this review, we outline how seed priming/conditioning affects the integrative role of hydrogen peroxide in seed germination and aging. PMID:26870076

Maternal vernalization and vernalization-pathway genes influence progeny seed germination.

PubMed

Auge, Gabriela A; Blair, Logan K; Neville, Hannah; Donohue, Kathleen

2017-10-01

Different life stages frequently respond to the same environmental cue to regulate development so that each life stage is matched to its appropriate season. We investigated how independently each life stage can respond to shared environmental cues, focusing on vernalization, in Arabidopsis thaliana plants. We first tested whether effects of rosette vernalization persisted to influence seed germination. To test whether genes in the vernalization flowering pathway also influence germination, we assessed germination of functional and nonfunctional alleles of these genes and measured their level of expression at different life stages in response to rosette vernalization. Rosette vernalization increased seed germination in diverse ecotypes. Genes in the vernalization flowering pathway also influenced seed germination. In the Columbia accession, functional alleles of most of these genes opposed the germination response observed in the ecotypes. Some genes influenced germination in a manner consistent with their known effects on FLOWERING LOCUS C gene regulation during the transition to flowering. Others did not, suggesting functional divergence across life stages. Despite persistent effects of environmental conditions across life stages, and despite pleiotropy of genes that affect both flowering and germination, the function of these genes can differ across life stages, potentially mitigating pleiotropic constraints and enabling independent environmental regulation of different life stages. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Synergistic and Antagonistic Effects of Salinity and pH on Germination in Switchgrass (Panicum virgatum L.)

PubMed Central

Liu, Yuan; Wang, Quanzhen; Zhang, Yunwei; Cui, Jian; Chen, Guo; Xie, Bao; Wu, Chunhui; Liu, Haitao

2014-01-01

The effects of salt-alkaline mixed stress on switchgrass were investigated by evaluating seed germination and the proline, malondialdehyde (MDA) and soluble sugar contents in three switchgrass (Panicum virgatum L.) cultivars in order to identify which can be successfully produced on marginal lands affected by salt-alkaline mixed stress. The experimental conditions consisted of four levels of salinity (10, 60, 110 and 160 mM) and four pH levels (7.1, 8.3, 9.5 and 10.7). The effects of salt-alkaline mixed stress with equivalent coupling of the salinity and pH level on the switchgrass were explored via model analyses. Switchgrass was capable of germinating and surviving well in all treatments under low-alkaline pH (pH≤8.3), regardless of the salinity. However, seed germination and seedling growth were sharply reduced at higher pH values in conjunction with salinity. The salinity and pH had synergetic effects on the germination percentage, germination index, plumular length and the soluble sugar and proline contents in switchgrass. However, these two factors exhibited antagonistic effects on the radicular length of switchgrass. The combined effects of salinity and pH and the interactions between them should be considered when evaluating the strength of salt-alkaline mixed stress. PMID:24454834

Light inhibits spore germination through phytochrome in Aspergillus nidulans.

PubMed

Röhrig, Julian; Kastner, Christian; Fischer, Reinhard

2013-05-01

Aspergillus nidulans responds to light in several aspects. The balance between sexual and asexual development as well as the amount of secondary metabolites produced is controlled by light. Here, we show that germination is largely delayed by blue (450 nm), red (700 nm), and far-red light (740 nm). The largest effect was observed with far-red light. Whereas 60 % of the conidia produced a germ tube after 20 h in the dark, less than 5 % of the conidia germinated under far-red light conditions. Because swelling of conidia was not affected, light appears to act at the stage of germ-tube formation. In the absence of nutrients, far-red light even inhibited swelling of conidia, whereas in the dark, conidia did swell and germinated after prolonged incubation. The blue-light signaling components, LreA (WC-1) and LreB (WC-2), and also the cryptochrome/photolyase CryA were not required for germination inhibition. However, in the phytochrome mutant, ∆fphA, the germination delay was released, but germination was delayed in the dark in comparison to wild type. This suggests a novel function of phytochrome as far-red light sensor and as activator of polarized growth in the dark.

Germination phenology determines the propensity for facilitation and competition.

PubMed

Leverett, Lindsay D

2017-09-01

A single plant can interact both positively and negatively with its neighbors through the processes of facilitation and competition, respectively. Much of the variation in the balance of facilitation and competition that individuals experience can be explained by the degree of physical stress and the sizes or ages of plants during the interaction. Germination phenology partly controls both of these factors, but its role in defining the facilitation-competition balance has not been explicitly considered. I performed an experiment in a population of the winter annual Arabidopsis thaliana (Brassicaceae) to test whether germinating during physically stressful periods leads to facilitation while germinating during periods that promote growth and reproduction leads to competition. I manipulated germination and neighbor presence across two years in order to quantify the effects of the local plant community on survival, fecundity, and total fitness as a function of germination phenology. Neighbors increased survival when germination occurred under conditions that were unsuitable for survival, but they reduced fecundity in germinants that were otherwise the most fecund. Later germination was associated with facilitation in the first year but competition in the second year. These episodes of facilitation and competition opposed each other, leading to no net effect of neighbors when averaged over all cohorts. These results indicate that variation in germination timing can explain some of the variation in the facilitation-competition balance in plant communities. © 2017 by the Ecological Society of America.

Germination of dimorphic seeds of Suaeda aralocaspica in response to light and salinity conditions during and after cold stratification

PubMed Central

Wang, Hong-Ling; Tian, Chang-Yan

2017-01-01

Cold stratification is a requirement for seed dormancy breaking in many species, and thus it is one of the important factors for the regulation of timing of germination. However, few studies have examined the influence of various environmental conditions during cold stratification on subsequent germination, and no study has compared such effects on the performance of dormant versus non-dormant seeds. Seeds of halophytes in the cold desert might experience different light and salinity conditions during and after cold stratification. As such, dimorphic seeds (non-dormant brown seeds and black seeds with non-deep physiological dormancy) of Suaeda aralocaspica were cold stratified under different light (12 h light–12 h darkness photoperiod or continuous darkness) or salinity (0, 200 or 1,000 mmol L-1 NaCl) conditions for 20 or 40 days. Then stratified seeds were incubated under different light or salinity conditions at daily (12/12 h) temperature regime of 10:25 °C for 20 days. For brown seeds, cold stratification was also part of the germination period. In contrast, almost no black seeds germinated during cold stratification. The longer the cold stratification, the better the subsequent germination of black seeds, regardless of light or salinity conditions. Light did not influence germination of brown seeds. Germination of cold-stratified black seeds was inhibited by darkness, especially when they were stratified in darkness. With an increase in salinity at the stage of cold stratification or germination, germination percentages of both seed morphs decreased. Combinational pre-treatments of cold stratification and salinity did not increase salt tolerance of dimorphic seeds in germination phase. Thus, light and salinity conditions during cold stratification partly interact with these conditions during germination stage and differentially affect germination of dimorphic seeds of S. aralocaspica. PMID:28828266

Effects of lanthanum and acid rain stress on the bio-sequestration of lanthanum in phytoliths in germinated rice seeds

PubMed Central

Si, Yong; Wang, Lihong; Huang, Xiaohua

2018-01-01

REEs in the environment can be absorbed by plants and sequestered by plant phytoliths. Acid rain can directly or indirectly affect plant physiological functions. Currently, the effects of REEs and acid rain on phytolith-REEs complex in plants are not yet fully understood. In this study, a high-silicon accumulation crop, rice (Oryza sativa L.), was selected as a representative of plants, and orthogonal experiments were conducted under various levels of lanthanum [La(III)] and pH. The results showed that various La(III) concentrations could significantly improve the efficiency and sequestration of phytolith La(III) in germinated rice seeds. A pH of 4.5 promoted phytolith La(III) sequestration, while a pH of 3.5 inhibited sequestration. Compared with the single treatment with La(III), the combination of La(III) and acid rain inhibited the efficiency and sequestration of phytolith La(III). Correlation analysis showed that the efficiency of phytolith La(III) sequestration had no correlation with the production of phytolith but was closely correlated with the sequestration of phytolith La(III) and the physiological changes of germinated rice seeds. Phytolith morphology was an important factor affecting phytolith La(III) sequestration in germinated rice seeds, and the effect of tubes on sequestration was more significant than that of dumbbells. This study demonstrated that the formation of the phytolith and La(III) complex could be affected by exogenous La(III) and acid rain in germinated rice seeds. PMID:29763463

Sinapic acid or its derivatives interfere with abscisic acid homeostasis during Arabidopsis thaliana seed germination.

PubMed

Bi, Baodi; Tang, Jingliang; Han, Shuang; Guo, Jinggong; Miao, Yuchen

2017-06-06

Sinapic acid and its esters have broad functions in different stages of seed germination and plant development and are thought to play a role in protecting against ultraviolet irradiation. To better understand the interactions between sinapic acid esters and seed germination processes in response to various stresses, we analyzed the role of the plant hormone abscisic acid (ABA) in the regulation of sinapic acid esters involved in seed germination and early seedling growth. We found that exogenous sinapic acid promotes seed germination in a dose-dependent manner in Arabidopsis thaliana. High-performance liquid chromatography mass spectrometry analysis showed that exogenous sinapic acid increased the sinapoylcholine content of imbibed seeds. Furthermore, sinapic acid affected ABA catabolism, resulting in reduced ABA levels and increased levels of the ABA-glucose ester. Using mutants deficient in the synthesis of sinapate esters, we showed that the germination of mutant sinapoylglucose accumulator 2 (sng2) and bright trichomes 1 (brt1) seeds was more sensitive to ABA than the wild-type. Moreover, Arabidopsis mutants deficient in either abscisic acid deficient 2 (ABA2) or abscisic acid insensitive 3 (ABI3) displayed increased expression of the sinapoylglucose:choline sinapoyltransferase (SCT) and sinapoylcholine esterase (SCE) genes with sinapic acid treatment. This treatment also affected the accumulation of sinapoylcholine and free choline during seed germination. We demonstrated that sinapoylcholine, which constitutes the major phenolic component in seeds among various minor sinapate esters, affected ABA homeostasis during seed germination and early seedling growth in Arabidopsis. Our findings provide insights into the role of sinapic acid and its esters in regulating ABA-mediated inhibition of Arabidopsis seed germination in response to drought stress.

Inter-specific variation in salinity effects on germination in Pacific Northwest tidal wetland plants

EPA Science Inventory

Environmental stressors such as salinity may affect plant germination and early growth, eventually impacting the distribution and abundance of more mature individuals. In a lab study we evaluated germination sensitivity to salinity in 13 tidal wetland species found in the Pacific...

Effects of a warmer climate on seed germination in the subarctic

PubMed Central

Milbau, Ann; Graae, Bente Jessen; Shevtsova, Anna; Nijs, Ivan

2009-01-01

Background and Aims In a future warmer subarctic climate, the soil temperatures experienced by dispersed seeds are likely to increase during summer but may decrease during winter due to expected changes in snow depth, duration and quality. Because little is known about the dormancy-breaking and germination requirements of subarctic species, how warming may influence the timing and level of germination in these species was examined. Methods Under controlled conditions, how colder winter and warmer summer soil temperatures influenced germination was tested in 23 subarctic species. The cold stratification and warm incubation temperatures were derived from real soil temperature measurements in subarctic tundra and the temperatures were gradually changed over time to simulate different months of the year. Key Results Moderate summer warming (+2·5 °C) substantially accelerated germination in all but four species but did not affect germination percentages. Optimum germination temperatures (20/10°C) further decreased germination time and increased germination percentages in three species. Colder winter soil temperatures delayed the germination in ten species and decreased the germination percentage in four species, whereas the opposite was found in Silene acaulis. In most species, the combined effect of a reduced snow cover and summer warming resulted in earlier germination and thus a longer first growing season, which improves the chance of seedling survival. In particular the recruitment of (dwarf) shrubs (Vaccinium myrtillus, V. vitis-idaea, Betula nana), trees (Alnus incana, Betula pubescens) and grasses (Calamagrostis lapponica, C. purpurea) is likely to benefit from a warmer subarctic climate. Conclusions Seedling establishment is expected to improve in a future warmer subarctic climate, mainly by considerably earlier germination. The magnitudes of the responses are species-specific, which should be taken into account when modelling population growth and migration

Germination and seedling establishment in orchids: a complex of requirements.

PubMed

Rasmussen, Hanne N; Dixon, Kingsley W; Jersáková, Jana; Těšitelová, Tamara

2015-09-01

Seedling recruitment is essential to the sustainability of any plant population. Due to the minute nature of seeds and early-stage seedlings, orchid germination in situ was for a long time practically impossible to observe, creating an obstacle towards understanding seedling site requirements and fluctuations in orchid populations. The introduction of seed packet techniques for sowing and retrieval in natural sites has brought with it important insights, but many aspects of orchid seed and germination biology remain largely unexplored. The germination niche for orchids is extremely complex, because it is defined by requirements not only for seed lodging and germination, but also for presence of a fungal host and its substrate. A mycobiont that the seedling can parasitize is considered an essential element, and a great diversity of Basidiomycota and Ascomycota have now been identified for their role in orchid seed germination, with fungi identifiable as imperfect Rhizoctonia species predominating. Specificity patterns vary from orchid species employing a single fungal lineage to species associating individually with a limited selection of distantly related fungi. A suitable organic carbon source for the mycobiont constitutes another key requirement. Orchid germination also relies on factors that generally influence the success of plant seeds, both abiotic, such as light/shade, moisture, substrate chemistry and texture, and biotic, such as competitors and antagonists. Complexity is furthermore increased when these factors influence seeds/seedling, fungi and fungal substrate differentially. A better understanding of germination and seedling establishment is needed for conservation of orchid populations. Due to the obligate association with a mycobiont, the germination niches in orchid species are extremely complex and varied. Microsites suitable for germination can be small and transient, and direct observation is difficult. An experimental approach using several

DNA damage checkpoint kinase ATM regulates germination and maintains genome stability in seeds

PubMed Central

Waterworth, Wanda M.; Footitt, Steven; Bray, Clifford M.; Finch-Savage, William E.; West, Christopher E.

2016-01-01

Genome integrity is crucial for cellular survival and the faithful transmission of genetic information. The eukaryotic cellular response to DNA damage is orchestrated by the DNA damage checkpoint kinases ATAXIA TELANGIECTASIA MUTATED (ATM) and ATM AND RAD3-RELATED (ATR). Here we identify important physiological roles for these sensor kinases in control of seed germination. We demonstrate that double-strand breaks (DSBs) are rate-limiting for germination. We identify that desiccation tolerant seeds exhibit a striking transcriptional DSB damage response during germination, indicative of high levels of genotoxic stress, which is induced following maturation drying and quiescence. Mutant atr and atm seeds are highly resistant to aging, establishing ATM and ATR as determinants of seed viability. In response to aging, ATM delays germination, whereas atm mutant seeds germinate with extensive chromosomal abnormalities. This identifies ATM as a major factor that controls germination in aged seeds, integrating progression through germination with surveillance of genome integrity. Mechanistically, ATM functions through control of DNA replication in imbibing seeds. ATM signaling is mediated by transcriptional control of the cell cycle inhibitor SIAMESE-RELATED 5, an essential factor required for the aging-induced delay to germination. In the soil seed bank, seeds exhibit increased transcript levels of ATM and ATR, with changes in dormancy and germination potential modulated by environmental signals, including temperature and soil moisture. Collectively, our findings reveal physiological functions for these sensor kinases in linking genome integrity to germination, thereby influencing seed quality, crucial for plant survival in the natural environment and sustainable crop production. PMID:27503884

DNA damage checkpoint kinase ATM regulates germination and maintains genome stability in seeds.

PubMed

Waterworth, Wanda M; Footitt, Steven; Bray, Clifford M; Finch-Savage, William E; West, Christopher E

2016-08-23

Genome integrity is crucial for cellular survival and the faithful transmission of genetic information. The eukaryotic cellular response to DNA damage is orchestrated by the DNA damage checkpoint kinases ATAXIA TELANGIECTASIA MUTATED (ATM) and ATM AND RAD3-RELATED (ATR). Here we identify important physiological roles for these sensor kinases in control of seed germination. We demonstrate that double-strand breaks (DSBs) are rate-limiting for germination. We identify that desiccation tolerant seeds exhibit a striking transcriptional DSB damage response during germination, indicative of high levels of genotoxic stress, which is induced following maturation drying and quiescence. Mutant atr and atm seeds are highly resistant to aging, establishing ATM and ATR as determinants of seed viability. In response to aging, ATM delays germination, whereas atm mutant seeds germinate with extensive chromosomal abnormalities. This identifies ATM as a major factor that controls germination in aged seeds, integrating progression through germination with surveillance of genome integrity. Mechanistically, ATM functions through control of DNA replication in imbibing seeds. ATM signaling is mediated by transcriptional control of the cell cycle inhibitor SIAMESE-RELATED 5, an essential factor required for the aging-induced delay to germination. In the soil seed bank, seeds exhibit increased transcript levels of ATM and ATR, with changes in dormancy and germination potential modulated by environmental signals, including temperature and soil moisture. Collectively, our findings reveal physiological functions for these sensor kinases in linking genome integrity to germination, thereby influencing seed quality, crucial for plant survival in the natural environment and sustainable crop production.

Effect of Environmental Factors on Germination and Emergence of Invasive Rumex confertus in Central Europe

PubMed Central

Kołodziejek, Jeremi; Patykowski, Jacek

2015-01-01

Rumex confertus is a biennial species native to Eastern Europe and Asia, where it thrives on meadow-steppes and glades in forest-steppe. This species has increased its range rapidly within central Europe, yet its biology is not well understood, which has led to poorly timed management. Effects of temperature, light, sodium chloride (NaCl), hydrogen ion concentration (pH), potassium nitrate (KNO3), and polyethylene glycol 6000 on seed germination were examined. Seedling emergence was examined for seeds sown at different depths in sand-filled pots. Seeds of R. confertus were nondormant at maturity. The germination percentage and rate of germination were significantly higher in light than in darkness. Secondary dormancy was induced in these seeds by 12 weeks of dark incubation at 4°C. The seeds of R. confertus undergo a seasonal dormancy cycle with deep dormancy in winter and early spring and a low level of dormancy in early autumn. Germination decreased as soil salinity increased. NO3 − increased the percentage and rate of germination in the studied species. Decrease in seedling emergence from the seeds buried at >0.5 cm may be due to deficiency of light. From our experiments, we conclude that the weed R. confertus normally becomes established in vegetation gaps or due to disturbance of the uppermost soil layer during the growing season through the germination of seeds originating from a long-lived seed bank. PMID:26229977

Phytochrome and Seed Germination. V. Changes of Phytochrome Content During the Germination of Cucumber Seeds 1

PubMed Central

Mancinelli, Alberto L.; Tolkowsky, Abby

1968-01-01

Cucumber seeds are light-sensitive, dark-germinating seeds. Inhibition of germination can be induced by prolonged exposure to continuous or intermittent FR. The dark germination process and the response to FR are phytochrome controlled. Phytochrome can be detected in these seeds by differential spectrophotometry in vivo. Spectrophotometrically measurable phytochrome increases during dark germination. The rate of increase is temperature dependent. Light treatments which are inhibitory for germination result in phytochrome contents lower than those of the seeds germinating in darkness. Treatments which restore germination also restore phytochrome formation. PMID:16656797

Germination and Inactivation of Alicyclobacillus acidoterrestris Spores Induced by Moderate Hydrostatic Pressure.

PubMed

Sokołowska, Barbara; Skapska, Sylwia; Fonberg-Broczek, Monika; Niezgoda, Jolanta; Porebska, Izabela; Dekowska, Agnieszka; Rzoska, Sylwester J

2015-01-01

Given the importance of spoilage caused by Alicyclobacillus acidoterrestris for the fruit juice industry, the objective of this work was to study the germination and inactivation of A. acidoterrestris spores induced by moderate hydrostatic pressure. Hydrostatic pressure treatment can induce the germination and inactivation of A. acidoterrestris spores. At low pH, spore germination of up to 3.59-3.75 log and inactivation of 1.85-2.04 log was observed in a low pressure window (200-300 MPa) applied at 50 degrees C for 20 min. Neutral pH suppressed inactivation, the number of spores inactivated at pH 7.0 was only 0.24-1.06 log. The pressurization temperature significantly affected spore germination and inactivation. The degree of germination in apple juice after pressurization for 30 min with 200 MPa at 20 degrees C was 2.04 log, with only 0.61 log of spores being inactivated, while at 70 degrees C spore germination was 5.94 log and inactivation 4.72 log. This temperature strongly stimulated germination and inactivation under higher (500 MPa) than lower (200 MPa) pressure. When the oscillatory mode was used, the degree of germination and inactivation was slightly higher than at continuous mode. The degree of germination and inactivation was inversely proportional to the soluble solids content and was lowest in concentrated apple juice.

Glucosinolates in broccoli sprouts (Brassica oleracea var. italica) as conditioned by sulphate supply during germination.

PubMed

Pérez-Balibrea, Santiago; Moreno, Diego A; García-Viguera, Cristina

2010-10-01

Sulphur (S) fertilization is essential for primary and secondary metabolism in cruciferous foods. Deficient, suboptimal, or excessive S affects the growth and biosynthesis of secondary metabolites in adult plants. Nevertheless, there is little information regarding the influence of S fertilization on sprouts and seedlings. An experiment was set up to evaluate the effect of S fertilization, supplied as K(2)SO(4) at 0, 15, 30, and 60 mg/L, on the glucosinolate content of broccoli sprouts during the germination course of 3, 6, 9, and 12 d after sowing. Glucosinolate concentration was strongly influenced by germination, causing a rapid increase during the first 3 d after sowing, and decreasing afterwards. The S supply increased aliphatic and total glucosinolate content at the end of the monitored sprouting period. S-treated sprouts, with S(15), S(30), and S(60) at 9 and 12 d after sowing presented enhanced glucosinolate content. Overall, both germination time and S fertilization were key factors in maximizing the bioactive health-promoting phytochemicals of broccoli. Practical Application: Germination with sulphate is a simple and inexpensive way to obtain sprouts that contain much higher levels of glucosinolates (health promoting compounds), than the corresponding florets from the same seeds.

Extra soil fertilization of mother plants increases botanical seed yield but not long-term germination in wild Solanum (potato) species

USDA-ARS?s Scientific Manuscript database

Potato has about 100 wild species relatives that are multiplied in the form of botanical seed populations by genebanks, and distributed for use in research and breeding, so factors that affect long term seed germination are of interest. In 1987 the US Potato Genebank conducted routine seed multiplic...

Seed dormancy and germination in Jeffersonia dubia (Berberidaceae) as affected by temperature and gibberellic acid.

PubMed

Rhie, Y H; Lee, S Y; Kim, K S

2015-03-01

The genus Jeffersonia, which contains only two species, has a trans-Atlantic disjunct distribution. The aims of this study were to determine the requirements for breaking dormancy and germination of J. dubia seeds and to compare its dormancy characteristics with those of the congener in eastern North America. Ripe seeds of J. dubia contain an underdeveloped embryo and were permeable to water. In nature, seeds were dispersed in May, while embryos began to grow in September, and were fully elongated by late November. Germination started in March of the next year, and seeds emerged as seedlings soon after germination. In laboratory experiments, incubation at high temperatures (25 °C, 25/15 °C) for at least 8 weeks was required to initiate embryo growth, while a transfer to moderate temperatures (20/10 °C, 15/6 °C) was needed for the completion of embryo growth. At least 8 weeks at 5 °C was effective in overcoming physiological dormancy and for germination in seeds after the embryos had fully elongated. Thus, both high and low temperatures were essential to break dormancy. Gibberellic acid (GA3 ) treatment could substitute for the high temperature requirement, but not for the low temperature requirement. Based on the dormancy-breaking requirements, it is confirmed that the seeds have deep simple morphophysiological dormancy. This dormancy type is similar to that of seeds of the eastern North American species J. diphylla. Although seeds require 10-11 months from seed dispersal to germination in nature, under controlled conditions they required only 3 months after treatment with 1000 mg·l(-1) GA3 , followed by incubation at 15/6 °C. This represents practical knowledge for propagation of these plants from seed. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Temperature, water activity and pH during conidia production affect the physiological state and germination time of Penicillium species.

PubMed

Nguyen Van Long, Nicolas; Vasseur, Valérie; Coroller, Louis; Dantigny, Philippe; Le Panse, Sophie; Weill, Amélie; Mounier, Jérôme; Rigalma, Karim

2017-01-16

Conidial germination and mycelial growth are generally studied with conidia produced under optimal conditions to increase conidial yield. Nonetheless, the physiological state of such conidia most likely differs from those involved in spoilage of naturally contaminated food. The present study aimed at investigating the impact of temperature, pH and water activity (a w ) during production of conidia on the germination parameters and compatible solutes of conidia of Penicillium roqueforti and Penicillium expansum. Low temperature (5°C) and reduced a w (0.900 a w ) during sporulation significantly reduced conidial germination times whereas the pH of the sporulation medium only had a slight effect at the tested values (2.5, 8.0). Conidia of P. roqueforti produced at 5°C germinated up to 45h earlier than those produced at 20°C. Conidia of P. roqueforti and P. expansum produced at 0.900 a w germinated respectively up to 8h and 3h earlier than conidia produced at 0.980 a w . Furthermore, trehalose and mannitol assessments suggested that earlier germination might be related to delayed conidial maturation even though no ultra-structural modifications were observed by transmission electron microscopy. Taken together, these results highlight the importance of considering environmental conditions during sporulation in mycological studies. The physiological state of fungal conidia should be taken into account to design challenge tests or predictive mycology studies. This knowledge may also be of interest to improve the germination capacity of fungal cultures commonly used in fermented foods. Copyright © 2016 Elsevier B.V. All rights reserved.

A Germination Simulation.

ERIC Educational Resources Information Center

Hershey, David R.

1995-01-01

Presents an activity that involves using sponge seedlings to demonstrate the germination process without the usual waiting period. Discusses epigeous versus hypogeous germination, and cotyledon number and biodiversity. (JRH)

Effects of a hypogeomagnetic field on gravitropism and germination in soybean

NASA Astrophysics Data System (ADS)

Mo, Wei-chuan; Zhang, Zi-jian; Liu, Ying; Zhai, Guang-jie; Jiang, Yuan-da; He, Rong-qiao

2011-05-01

Any plants grown during long-term space missions will inevitably experience an extremely low magnetic field (i.e. a hypogeomagnetic field, HGMF). It is possible that the innate adaptation of plants to the earth's magnetic field (i.e. the geomagnetic field, GMF) would be disrupted. Effects of the HGMF on plant physiological and metabolic processes are unclear. In this study we established a hypogeomagnetic incubation system on the ground and investigated the effects of the HGMF on the gravitropism and germination of soybean seeds. The gravitropism angle, germination percentage, germination speed, water absorbance ratio, seed weight, radicle length, radicle weight, and radicle weight ratio of soybean seeds grown in the local field and the HGMF were compared. In general, the gravitropism angle in the HGMF was smaller than that in the local field when seeds were positioned before emergence in such a way that the direction of the radicle was opposite to that of gravity. The germination percentage, germination speed, and radicle weight ratio increased in the HGMF compared to the control. Our results indicate that the germination and gravitropism of soybean seeds are affected by elimination of the geomagnetic field.

Genetic Variation for Thermotolerance in Lettuce Seed Germination Is Associated with Temperature-Sensitive Regulation of ETHYLENE RESPONSE FACTOR1 (ERF1)1[OPEN

PubMed Central

O’Brien, Laurel K.; Truco, Maria Jose; Huo, Heqiang; Sideman, Rebecca; Hayes, Ryan; Michelmore, Richard W.

2016-01-01

Seeds of most lettuce (Lactuca sativa) cultivars are susceptible to thermoinhibition, or failure to germinate at temperatures above approximately 28°C, creating problems for crop establishment in the field. Identifying genes controlling thermoinhibition would enable the development of cultivars lacking this trait and, therefore, being less sensitive to high temperatures during planting. Seeds of a primitive accession (PI251246) of lettuce exhibited high-temperature germination capacity up to 33°C. Screening a recombinant inbred line population developed from PI215246 and cv Salinas identified a major quantitative trait locus (Htg9.1) from PI251246 associated with the high-temperature germination phenotype. Further genetic analyses discovered a tight linkage of the Htg9.1 phenotype with a specific DNA marker (NM4182) located on a single genomic sequence scaffold. Expression analyses of the 44 genes encoded in this genomic region revealed that only a homolog of Arabidopsis (Arabidopsis thaliana) ETHYLENE RESPONSE FACTOR1 (termed LsERF1) was differentially expressed between PI251246 and cv Salinas seeds imbibed at high temperature (30°C). LsERF1 belongs to a large family of transcription factors associated with the ethylene-signaling pathway. Physiological assays of ethylene synthesis, response, and action in parental and near-isogenic Htg9.1 genotypes strongly implicate LsERF1 as the gene responsible for the Htg9.1 phenotype, consistent with the established role for ethylene in germination thermotolerance of Compositae seeds. Expression analyses of genes associated with the abscisic acid and gibberellin biosynthetic pathways and results of biosynthetic inhibitor and hormone response experiments also support the hypothesis that differential regulation of LsERF1 expression in PI251246 seeds elevates their upper temperature limit for germination through interactions among pathways regulated by these hormones. Our results support a model in which LsERF1 acts through

Arabidopsis WRKY6 Transcription Factor Acts as a Positive Regulator of Abscisic Acid Signaling during Seed Germination and Early Seedling Development

PubMed Central

Wu, Wei-Hua; Chen, Yi-Fang

2016-01-01

The phytohormone abscisic acid (ABA) plays important roles during seed germination and early seedling development. Here, we characterized the function of the Arabidopsis WRKY6 transcription factor in ABA signaling. The transcript of WRKY6 was repressed during seed germination and early seedling development, and induced by exogenous ABA. The wrky6-1 and wrky6-2 mutants were ABA insensitive, whereas WRKY6-overexpressing lines showed ABA-hypersensitive phenotypes during seed germination and early seedling development. The expression of RAV1 was suppressed in the WRKY6-overexpressing lines and elevated in the wrky6 mutants, and the expression of ABI3, ABI4, and ABI5, which was directly down-regulated by RAV1, was enhanced in the WRKY6-overexpressing lines and repressed in the wrky6 mutants. Electrophoretic mobility shift and chromatin immunoprecipitation assays showed that WRKY6 could bind to the RAV1 promoter in vitro and in vivo. Overexpression of RAV1 in WRKY6-overexpressing lines abolished their ABA-hypersensitive phenotypes, and the rav1 wrky6-2 double mutant showed an ABA-hypersensitive phenotype, similar to rav1 mutant. Together, the results demonstrated that the Arabidopsis WRKY6 transcription factor played important roles in ABA signaling by directly down-regulating RAV1 expression. PMID:26829043

GERMINATOR: a software package for high-throughput scoring and curve fitting of Arabidopsis seed germination.

PubMed

Joosen, Ronny V L; Kodde, Jan; Willems, Leo A J; Ligterink, Wilco; van der Plas, Linus H W; Hilhorst, Henk W M

2010-04-01

Over the past few decades seed physiology research has contributed to many important scientific discoveries and has provided valuable tools for the production of high quality seeds. An important instrument for this type of research is the accurate quantification of germination; however gathering cumulative germination data is a very laborious task that is often prohibitive to the execution of large experiments. In this paper we present the germinator package: a simple, highly cost-efficient and flexible procedure for high-throughput automatic scoring and evaluation of germination that can be implemented without the use of complex robotics. The germinator package contains three modules: (i) design of experimental setup with various options to replicate and randomize samples; (ii) automatic scoring of germination based on the color contrast between the protruding radicle and seed coat on a single image; and (iii) curve fitting of cumulative germination data and the extraction, recap and visualization of the various germination parameters. The curve-fitting module enables analysis of general cumulative germination data and can be used for all plant species. We show that the automatic scoring system works for Arabidopsis thaliana and Brassica spp. seeds, but is likely to be applicable to other species, as well. In this paper we show the accuracy, reproducibility and flexibility of the germinator package. We have successfully applied it to evaluate natural variation for salt tolerance in a large population of recombinant inbred lines and were able to identify several quantitative trait loci for salt tolerance. Germinator is a low-cost package that allows the monitoring of several thousands of germination tests, several times a day by a single person.

A new insight into arable weed adaptive evolution: mutations endowing herbicide resistance also affect germination dynamics and seedling emergence

PubMed Central

Délye, Christophe; Menchari, Yosra; Michel, Séverine; Cadet, Émilie; Le Corre, Valérie

2013-01-01

Background and Aims Selective pressures exerted by agriculture on populations of arable weeds foster the evolution of adaptive traits. Germination and emergence dynamics and herbicide resistance are key adaptive traits. Herbicide resistance alleles can have pleiotropic effects on a weed's life cycle. This study investigated the pleiotropic effects of three acetyl-coenzyme A carboxylase (ACCase) alleles endowing herbicide resistance on the seed-to-plant part of the life cycle of the grass weed Alopecurus myosuroides. Methods In each of two series of experiments, A. myosuroides populations with homogenized genetic backgrounds and segregating for Leu1781, Asn2041 or Gly2078 ACCase mutations which arose independently were used to compare germination dynamics, survival in the soil and seedling pre-emergence growth among seeds containing wild-type, heterozygous and homozygous mutant ACCase embryos. Key Results Asn2041 ACCase caused no significant effects. Gly2078 ACCase major effects were a co-dominant acceleration in seed germination (1·25- and 1·10-fold decrease in the time to reach 50 % germination (T50) for homozygous and heterozygous mutant embryos, respectively). Segregation distortion against homozygous mutant embryos or a co-dominant increase in fatal germination was observed in one series of experiments. Leu1781 ACCase major effects were a co-dominant delay in seed germination (1·41- and 1·22-fold increase in T50 for homozygous and heterozygous mutant embryos, respectively) associated with a substantial co-dominant decrease in fatal germination. Conclusions Under current agricultural systems, plants carrying Leu1781 or Gly2078 ACCase have a fitness advantage conferred by herbicide resistance that is enhanced or counterbalanced, respectively, by direct pleiotropic effects on the plant phenology. Pleiotropic effects associated with mutations endowing herbicide resistance undoubtedly play a significant role in the evolutionary dynamics of herbicide resistance

A new insight into arable weed adaptive evolution: mutations endowing herbicide resistance also affect germination dynamics and seedling emergence.

PubMed

Délye, Christophe; Menchari, Yosra; Michel, Séverine; Cadet, Emilie; Le Corre, Valérie

2013-04-01

Selective pressures exerted by agriculture on populations of arable weeds foster the evolution of adaptive traits. Germination and emergence dynamics and herbicide resistance are key adaptive traits. Herbicide resistance alleles can have pleiotropic effects on a weed's life cycle. This study investigated the pleiotropic effects of three acetyl-coenzyme A carboxylase (ACCase) alleles endowing herbicide resistance on the seed-to-plant part of the life cycle of the grass weed Alopecurus myosuroides. In each of two series of experiments, A. myosuroides populations with homogenized genetic backgrounds and segregating for Leu1781, Asn2041 or Gly2078 ACCase mutations which arose independently were used to compare germination dynamics, survival in the soil and seedling pre-emergence growth among seeds containing wild-type, heterozygous and homozygous mutant ACCase embryos. Asn2041 ACCase caused no significant effects. Gly2078 ACCase major effects were a co-dominant acceleration in seed germination (1·25- and 1·10-fold decrease in the time to reach 50 % germination (T50) for homozygous and heterozygous mutant embryos, respectively). Segregation distortion against homozygous mutant embryos or a co-dominant increase in fatal germination was observed in one series of experiments. Leu1781 ACCase major effects were a co-dominant delay in seed germination (1·41- and 1·22-fold increase in T50 for homozygous and heterozygous mutant embryos, respectively) associated with a substantial co-dominant decrease in fatal germination. Under current agricultural systems, plants carrying Leu1781 or Gly2078 ACCase have a fitness advantage conferred by herbicide resistance that is enhanced or counterbalanced, respectively, by direct pleiotropic effects on the plant phenology. Pleiotropic effects associated with mutations endowing herbicide resistance undoubtedly play a significant role in the evolutionary dynamics of herbicide resistance in weed populations. Mutant ACCase alleles should

Desiccation and Cold Hardening of Date Palm Somatic Embryos Improve Germination.

PubMed

Shareef, Hussein J

2017-01-01

Embryogenic suspension cultures of date palm are ideal for mass propagation of somatic embryos; however, the low percentage of germination of somatic embryos (SE) remains an impediment. This chapter focuses on two important physical factors to improve germination of date palm somatic embryos: the use of partial desiccation (3 h) of somatic embryos and the exposure to low temperature (4 °C for 24 h). High germination percentage (41%) is achieved by desiccation for 3 h. Moreover, adding 0.3 g/L activated charcoal (AC) to the liquid medium further improves somatic embryo number and weight as well as the percentage of germination. Moreover, partial desiccation and low temperature exposure tend to increase proline content. This improved protocol for somatic embryo germination is potentially applicable for commercial micropropagation of date palm.

Effects of acidity on tree pollen germination and tube growth

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

Jacobson, J.S.; Van Rye, D.M.; Lassoie, J.P.

Several studies have indicated that pollen germination and tube growth are adversely affected by air pollutants. Pollutants may inhibit the function of pollen by reducing the number of pollen grains which germinate, by reducing the maximum length to which the pollen tubes grow, or by interfering with the formation of the generative cell. The paper reports on studies that are attempting to determine the effects acid rain may have on these crucial stages in the life histories of northeastern tree species. The first stage of this work assessed the effects of acidity in the growth medium on in vitro pollenmore » germination for four deciduous forest species common to central New York State, Betula lutea (yellow birch), B. lenta (black birch), Acer saccharum (sugar maple), and Cornus florida (flowering dogwood). Measurements were taken at the end of the growth period to determine the percentage of grains which had germinated, and to estimate the average tube length. To determine the effects of pollen on the growth medium, the pH of the germination drop was measured at the end of the growth period.« less

The maturation and germination of Phytophthora ramorum Chlamydospores

Treesearch

Aaron L. Smith; Everett M. Hansen

2008-01-01

Chlamydospores are a distinctive feature of Phytophthora ramorum. They are formed quickly in agar, and within colonized leaves. We followed their development and maturation in vitro and in vivo, and studied conditions affecting their germination. Cell walls of mature P. ramorum chlamydospores...

Improving Germination of Nuttall Oak Acorns

Treesearch

R. L. Johnson

1967-01-01

Under simulated field conditions the best treatment for germination of acorns of Quercus nuttallii Palmer was a combination of sowing 1 inch below soil surface, under litter, and in partial shade. Supplemental watering was also advantageous. The most important factor was depth of sowing.

BP-ANN for Fitting the Temperature-Germination Model and Its Application in Predicting Sowing Time and Region for Bermudagrass

PubMed Central

Pi, Erxu; Mantri, Nitin; Ngai, Sai Ming; Lu, Hongfei; Du, Liqun

2013-01-01

Temperature is one of the most significant environmental factors that affects germination of grass seeds. Reliable prediction of the optimal temperature for seed germination is crucial for determining the suitable regions and favorable sowing timing for turf grass cultivation. In this study, a back-propagation-artificial-neural-network-aided dual quintic equation (BP-ANN-QE) model was developed to improve the prediction of the optimal temperature for seed germination. This BP-ANN-QE model was used to determine optimal sowing times and suitable regions for three Cynodon dactylon cultivars (C. dactylon, ‘Savannah’ and ‘Princess VII’). Prediction of the optimal temperature for these seeds was based on comprehensive germination tests using 36 day/night (high/low) temperature regimes (both ranging from 5/5 to 40/40°C with 5°C increments). Seed germination data from these temperature regimes were used to construct temperature-germination correlation models for estimating germination percentage with confidence intervals. Our tests revealed that the optimal high/low temperature regimes required for all the three bermudagrass cultivars are 30/5, 30/10, 35/5, 35/10, 35/15, 35/20, 40/15 and 40/20°C; constant temperatures ranging from 5 to 40°C inhibited the germination of all three cultivars. While comparing different simulating methods, including DQEM, Bisquare ANN-QE, and BP-ANN-QE in establishing temperature based germination percentage rules, we found that the R2 values of germination prediction function could be significantly improved from about 0.6940–0.8177 (DQEM approach) to 0.9439–0.9813 (BP-ANN-QE). These results indicated that our BP-ANN-QE model has better performance than the rests of the compared models. Furthermore, data of the national temperature grids generated from monthly-average temperature for 25 years were fit into these functions and we were able to map the germination percentage of these C. dactylon cultivars in the national scale of

Arabidopsis ABI5 plays a role in regulating ROS homeostasis by activating CATALASE 1 transcription in seed germination.

PubMed

Bi, Chao; Ma, Yu; Wu, Zhen; Yu, Yong-Tao; Liang, Shan; Lu, Kai; Wang, Xiao-Fang

2017-05-01

It has been known that ABA INSENSITIVE 5 (ABI5) plays a vital role in regulating seed germination. In the present study, we showed that inhibition of the catalase activity with 3-amino-1,2,4-triazole (3-AT) inhibits seed germination of Col-0, abi5 mutants and ABI5-overexpression transgenic lines. Compared with Col-0, the seeds of abi5 mutants showed more sensitive to 3-AT during seed germination, while the seeds of ABI5-overexpression transgenic lines showed more insensitive. H 2 O 2 showed the same effect on seed germination of Col-0, abi5 mutants and ABI5-overexpression transgenic lines as 3-AT. These results suggest that ROS is involved in the seed germination mediated by ABI5. Further, we observed that T-DNA insertion mutants of the three catalase members in Arabidopsis displayed 3-AT-insensitive or -hypersensitive phenotypes during seed germination, suggesting that these catalase members regulate ROS homeostasis in a highly complex way. ABI5 affects reactive oxygen species (ROS) homeostasis by affecting CATALASE expression and catalase activity. Furthermore, we showed that ABI5 directly binds to the CAT1 promoter and activates CAT1 expression. Genetic evidence supports the idea that CAT1 functions downstream of ABI5 in ROS signaling during seed germination. RNA-sequencing analysis indicates that the transcription of the genes involved in ROS metabolic process or genes responsive to ROS stress is impaired in abi5-1 seeds. Additionally, expression changes in some genes correlative to seed germination were showed due to the change in ABI5 expression under 3-AT treatment. Together, all the findings suggest that ABI5 regulates seed germination at least partly by affecting ROS homeostasis.

New insights into the early steps of oil body mobilization during pollen germination

PubMed Central

Castro, Antonio Jesús

2013-01-01

In some plants, pollen grains accumulate storage lipids that serve as energy supply during germination. Here, three enzymes involved in early steps of oil body mobilization in the male gametophyte were functionally characterized for the first time. The effect of extracellular sugars on pollen performance and oil body dynamics was also analysed. Olive pollen oil bodies showed phospholipase A, lipase, and lipoxygenase activities on their surface. Enzyme activity levels increased during germination with a maximum after 3h. Removal of extracellular sugars from the germination medium did not affect pollen performance but increased enzyme activity rates and sped up oil body mobilization. Inhibitors seriously hampered pollen germination and pollen tube growth, leading to a characteristic accumulation of oil bodies in the germinative aperture. It can be concluded that storage lipids are sufficient for proper olive pollen germination. A lipase and a lipoxygenase are likely involved in oil body mobilization. Extracellular sugars may modulate their function, while a phospholipase A may promote their access to the storage lipids. PMID:23132905

Germination Biology of Two Invasive Physalis Species and Implications for Their Management in Arid and Semi-arid Regions.

PubMed

Ozaslan, Cumali; Farooq, Shahid; Onen, Huseyin; Ozcan, Selcuk; Bukun, Bekir; Gunal, Hikmet

2017-12-05

Two Solanaceae invasive plant species (Physalis angulata L. and P. philadelphica Lam. var. immaculata Waterfall) infest several arable crops and natural habitats in Southeastern Anatolia region, Turkey. However, almost no information is available regarding germination biology of both species. We performed several experiments to infer the effects of environmental factors on seed germination and seedling emergence of different populations of both species collected from various locations with different elevations and habitat characteristics. Seed dormancy level of all populations was decreased with increasing age of the seeds. Seed dormancy of freshly harvested and aged seeds of all populations was effectively released by running tap water. Germination was slightly affected by photoperiods, which suggests that seeds are slightly photoblastic. All seeds germinated under wide range of temperature (15-40 °C), pH (4-10), osmotic potential (0 to -1.2 MPa) and salinity (0-400 mM sodium chloride) levels. The germination ability of both plant species under wide range of environmental conditions suggests further invasion potential towards non-infested areas in the country. Increasing seed burial depth significantly reduced the seedling emergence, and seeds buried below 4 cm of soil surface were unable to emerge. In arable lands, soil inversion to maximum depth of emergence (i.e., 6 cm) followed by conservational tillage could be utilized as a viable management option.

Magnetic-time model at off-season germination

NASA Astrophysics Data System (ADS)

Mahajan, Tarlochan Singh; Pandey, Om Prakash

2014-03-01

Effect of static magnetic field on germination of mung beans is described. Seeds of mung beans, were exposed in batches to static magnetic fields of 87 to 226 mT intensity for 100 min. Magnetic time constant - 60.743 Th (Tesla hour) was determined experimentally. High value of magnetic time constant signifies lower effect of magnetic field on germination rate as this germination was carried out at off-season (13°C). Using decay function, germination magnetic constant was calculated. There was a linear increase in germination magnetic constant with increasing intensity of magnetic field. Calculated values of mean germination time, mean germination rate, germination rate coefficient, germination magnetic constant, transition time, water uptake, indicate that the impact of applied static magnetic field improves the germination of mung beans seeds even in off-season

Effects of temperature, light and incubation period on production, germination and bioactivity of Trichoderma atroviride.

PubMed

Daryaei, A; Jones, E E; Ghazalibiglar, H; Glare, T R; Falloon, R E

2016-04-01

The goal was to determine the effect of temperature, light and incubation period on production, germination and bioactivity of Trichoderma atroviride LU132 against Rhizoctonia solani. The incubation temperatures of 20, 25 or 30°C were assessed on the production of T. atroviride conidia under constant light over a 25 and 50 days periods. The resulting conidia were also studied for germination and bioactivity. Conidium production was maximum at 25°C after 20 days. The second peak of conidium production occurred at 45-50 days. Incubation at 25°C after 15 days showed optimum production of T. atroviride LU132. Conidia produced at 30°C gave the greatest germination and bioactivity in comparison with incubation at 20 or 25°C. This study indicates that the temperature at which conidia of T. atroviride are produced affects germination and bioactivity. Formulations based on production of the high conidia yield may not result in optimal bioactivity and there is a trade-off between quantity and quality of T. atroviride LU132 conidia. Conidium production was shown to be a continuous process, and increased under a dark/light regime. This is the first report of bimodal conidium production in a Trichoderma biological control agent (BCA), which is likely to be on 20 days cycle, and is dependent on colony age rather than abiotic factors. Conidia produced after 15 days are likely to be the most suitable for use in commercial production of this strain as a BCA. Most studies on Trichoderma-based BCA have only shown the effect of culture conditions on the high conidia yield regardless of conidium quality. This study is the first report on conidium quality affected by principal culture conditions for Trichoderma biological control formulations. © 2016 The Society for Applied Microbiology.

Germination of Medicago sativa is inhibited by soluble compounds in cement dust.

PubMed

Lafragüeta, Cristina; García-Criado, Balbino; Arranz, Angel; Vázquez-de-Aldana, Beatriz R

2014-01-01

Deposition of cement dust on soils and plant surfaces is known to affect plant growth and the species composition of plant communities, but little is known about its effects (and those of its pH and constituents) on germination. Therefore, the aim of this study was to assess the toxicity of an aqueous cement extract, constituents of the extract and pH on the germination of seeds of a selected species, Medicago sativa. First, the effects of the extract were tested in assays with concentrations and exposure durations ranging from 0 to 1.0 g/mL and 4 to 96 h, respectively. At 0.8 g/mL, the extract strongly inhibited germination; a 4-h exposure reduced the germination rate, from 77 ± 1.8 to 50 ± 2.6% (mean ± SE), while 8-h exposure completely inhibited it. Further, treatment at this concentration killed the non-germinating seeds, thus the inhibition was due to toxic effects. Neither the pH of the extract nor the concentration of its main soluble elements separately (K, Ca, S, Na, or Cr) caused the toxicity since germination rates were not significantly reduced when these variables were tested individually. However, a mixture of the elements in solution reduced germination rates, suggesting that they have adverse synergistic effects.

Germination Requirements of Bacillus macerans Spores

PubMed Central

Sacks, L. E.; Thompson, P. A.

1971-01-01

2-Phenylacetamide is an effective germinant for spores of five strains of Bacillus macerans, particularly in the presence of fructose. Benzyl penicillin, the phenyl acetamide derivative of penicillin, and phenylacetic acid are also good germinants. l-Asparagine is an excellent germinant for four strains. α-Amino-butyric acid is moderately effective. Pyridoxine, pyridoxal, adenine, and 2,6-diaminopurine are potent germinants for NCA strain 7X1 only. d-Glucose is a powerful germinant for strain B-70 only. d-Fructose and d-ribose strongly potentiate germination induced by other germinants (except l-asparagine) but have only weak activity by themselves. Niacinamide and nicotinamide-adenine dinucleotide, inactive by themselves, are active in the presence of fructose or ribose. Effects of pH, ion concentration, and temperature are described. PMID:4251279

The Transcriptional Coregulator LEUNIG_HOMOLOG Inhibits Light-Dependent Seed Germination in Arabidopsis

PubMed Central

Lee, Nayoung; Park, Jeongmoo; Kim, Keunhwa; Choi, Giltsu

2015-01-01

PHYTOCHROME-INTERACTING FACTOR1 (PIF1) is a basic helix-loop-helix transcription factor that inhibits light-dependent seed germination in Arabidopsis thaliana. However, it remains unclear whether PIF1 requires other factors to regulate its direct targets. Here, we demonstrate that LEUNIG_HOMOLOG (LUH), a Groucho family transcriptional corepressor, binds to PIF1 and coregulates its targets. Not only are the transcriptional profiles of the luh and pif1 mutants remarkably similar, more than 80% of the seeds of both genotypes germinate in the dark. We show by chromatin immunoprecipitation that LUH binds a subset of PIF1 targets in a partially PIF1-dependent manner. Unexpectedly, we found LUH binds and coregulates not only PIF1-activated targets but also PIF1-repressed targets. Together, our results indicate LUH functions with PIF1 as a transcriptional coregulator to inhibit seed germination. PMID:26276832

Can heavy metal pollution defend seed germination against heat stress? Effect of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination under high temperature.

PubMed

Deng, Benliang; Yang, Kejun; Zhang, Yifei; Li, Zuotong

2016-09-01

Heavy metal pollution, as well as greenhouse effect, has become a serious threat today. Both heavy metal and heat stresses can arrest seed germination. What response can be expected for seed germination under both stress conditions? Here, the effects of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination were investigated at 20 °C and 40 °C. Compared with 20 °C, heat stress induced thermodormancy. However, this thermodormancy could be significantly alleviated by the addition of a low concentration of heavy metals. Heavy metals, as well as heat stress induced H2O2 accumulation in germinating seeds. Interestingly, this low concentration of heavy metal that promoted seed germination could be partly blocked by DMTU (a specific ROS scavenger), irrespective of temperature. Accordingly, H2O2 addition reinforced this promoting effect on seed germination, which was induced by a low concentration of heavy metal. Furthermore, we found that the NADPH oxidase derived ROS was required for seed germination promoted by the heavy metals. Subsequently, treatment of seeds with fluridone (a specific inhibitor of ABA) or ABA significantly alleviated or aggravated thermodormancy, respectively. However, this alleviation or aggravation could be partly attenuated by a low concentration of heavy metals. In addition, germination that was inhibited by high concentrations of heavy metals was also partly reversed by fluridone. The obtained results support the idea that heavy metal-mediated ROS and hormone interaction can finally affect the thermodormancy release or not. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of gamma and electron beam irradiation in reducing populations of E. coli artificially inoculated on mung bean, clover and fenugreek seeds, and affecting germination and growth of seeds

NASA Astrophysics Data System (ADS)

Fan, Xuetong; Sokorai, Kimberly; Weidauer, André; Gotzmann, Gaby; Rögner, Frank-Holm; Koch, Eckhard

2017-01-01

Sprouts have frequently been implicated in outbreaks of foodborne illnesses, mostly due to contaminated seeds. Intervention technologies to decontaminate seeds without affecting sprout yield are needed. In the present study, we compared gamma rays with electron beam in inactivating E. coli artificially inoculated on three seeds (fenugreek, clover and mung bean) that differed in size and surface morphology. Furthermore, the germination and growth of irradiated seeds were evaluated. Results showed that the D10 values (dose required to achieve 1 log reduction) for E. coli K12 on mung bean, clover, and fenugreek were 1.11, 1.21 and 1.40 kGy, respectively. To achieve a minimum 5-log reduction of E. coli, higher doses were needed on fenugreek than on mung bean or clover. Electron beam treatment at doses up to 12 kGy could not completely inactivate E. coli inoculated on all seeds even though most of the seeds were E. coli-free after 4-12 kGy irradiation. Gamma irradiation at doses up to 6 kGy did not significantly affect the germination rate of clover and fenugreek seeds but reduced the germination rate of mung bean seeds. Doses of 2 kGy gamma irradiation did not influence the growth of seeds while higher doses of gamma irradiation reduced the growth rate. Electron beam treatment at doses up to 12 kGy did not have any significant effect on germination or growth of the seeds. SEM imaging indicated there were differences in surface morphology among the three seeds, and E. coli resided in cracks and openings of seeds, making surface decontamination of seeds with low energy electron beam a challenge due to the low penetration ability. Overall, our results suggested that gamma rays and electron beam had different effects on E. coli inactivation and germination or growth of seeds. Future efforts should focus on optimization of electron bean parameters to increase penetration to inactivate E. coli without causing damage to the seeds.

Abscisic acid regulates seed germination of Vellozia species in response to temperature.

PubMed

Vieira, B C; Bicalho, E M; Munné-Bosch, S; Garcia, Q S

2017-03-01

The relationship between the phytohormones, gibberellin (GA) and abscisic acid (ABA) and light and temperature on seed germination is still not well understood. We aimed to investigate the role of the ABA and GA on seed germination of Vellozia caruncularis, V. intermedia and V. alutacea in response to light/dark conditions on different temperature. Seeds were incubated in GA (GA 3 or GA 4 ) or ABA and their respective biosynthesis inhibitors (paclobutrazol - PAC, and fluridone - FLU) solutions at two contrasting temperatures (25 and 40 °C). Furthermore, endogenous concentrations of active GAs and those of ABA were measured in seeds of V. intermedia and V. alutacea during imbibition/germination. Exogenous ABA inhibited the germination of Vellozia species under all conditions tested. GA, FLU and FLU + GA 3 stimulated germination in the dark at 25 °C (GA 4 being more effective than GA 3 ). PAC reduced seed germination in V. caruncularis and V. alutacea, but did not affect germination of V. intermedia at 40 °C either under light or dark conditions. During imbibition in the dark, levels of active GAs decreased in the seeds of V. intermedia, but were not altered in those of V. alutacea. Incubation at 40 °C decreased ABA levels during imbibition in both V. caruncularis and V. alutacea. We conclude that the seeds of Vellozia species studied here require light or high temperature to germinate and ABA has a major role in the regulation of Vellozia seed germination in response to light and temperature. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effect of Fertilizers and Neem Cake Amendment in Soil on Spore Germination of Arthrobotrys dactyloides

PubMed Central

Kumar, D.; Jaiswal, R. K.

2005-01-01

Application of fertilizers such as urea, diammonium phosphate (DAP) and muriate of potash in soil adversely affected the spore germination of Arthrobotrys dactyloides. Amendment of soil with urea at the concentrations of 1.0%, 0.5% and 0.1% completely inhibited spore germination and direct trap formation on the conidium, whereas muriate of potash delayed and reduced the spore germination even at the lowest concentration. DAP also inhibited spore germination at 1.0% concentration, while at lower concentration the percentage of spore germination was reduced. Application of neem cake at the concentration of 0.5% also inhibited spore germination after 24 h of amendment. The inhibitory effect of neem cake was reduced after 15 days of amendment, while after 30 days after amendment the inhibitory effect was completely lost and the spore germinated by direct trap as in unamended soil. Nematodes were not attracted to ungerminated spores after 24 h of amendment. After 15 days of amendment nematodes were attracted to agar blocks containing fewer germinated spores after 24 h of incubation but after 48 h of incubation large number of nematodes were attracted and trapped by the germinated spores with direct traps. After 30 days of amendment, larger number of nematodes were attracted and trapped by direct traps. PMID:24049500

Phytochrome B and REVEILLE1/2-mediated signalling controls seed dormancy and germination in Arabidopsis.

PubMed

Jiang, Zhimin; Xu, Gang; Jing, Yanjun; Tang, Weijiang; Lin, Rongcheng

2016-08-10

Seeds maintain a dormant state to withstand adverse conditions and germinate when conditions become favourable to give rise to a new generation of flowering plants. Seed dormancy and germination are tightly controlled by internal and external signals. Although phytochrome photoreceptors are proposed to regulate primary seed dormancy, the underlying molecular mechanism remains elusive. Here we show that the REVEILLE1 (RVE1) and RVE2 transcription factors promote primary seed dormancy and repress red/far-red-light-reversible germination downstream of phytochrome B (phyB) in Arabidopsis thaliana. RVE1 and RVE2 expression is downregulated after imbibition and by phyB. RVE1 directly binds to the promoter of GIBBERELLIN 3-OXIDASE 2, inhibits its transcription and thus suppresses the biosynthesis of bioactive gibberellins. In addition, DELAY OF GERMINATION 1 also acts downstream of phyB. This study identifies a signalling pathway that integrates environmental light input with internal factors to control both seed dormancy and germination.

Regulation and Characterization of a Newly Deduced Cell Wall Hydrolase Gene (cwlJ) Which Affects Germination of Bacillus subtilis Spores

PubMed Central

Ishikawa, Shu; Yamane, Kunio; Sekiguchi, Junichi

1998-01-01

The predicted amino acid sequence of Bacillus subtilis ycbQ (renamed cwlJ) exhibits high similarity to those of the deduced C-terminal catalytic domain of SleBs, the specific cortex-hydrolyzing enzyme of B. cereus and the deduced one of B. subtilis. We constructed a cwlJ::lacZ fusion in the B. subtilis chromosome. The β-galactosidase activity and results of Northern hybridization and primer extension analyses of the cwlJ gene indicated that it is transcribed by EςE RNA polymerase. cwlJ-deficient spores responded to both l-alanine and AGFK, the A580 values of spore suspensions decreased more slowly than in the case of the wild-type strain, and the mutant spores released less dipicolinic acid than did those of the wild-type strain during germination. However, the mutant spores released only slightly less hexosamine than did the wild-type spores. In contrast, B. subtilis sleB spores did not release hexosamine at a significant level. While cwlJ and sleB spores were able to germinate, CJSB (cwlJ sleB) spores could not germinate but exhibited initial germination reactions, e.g., partial decrease in A580 and slow release of dipicolinic acid. CJSB spores became slightly gray after 6 h in the germinant, but their refractility was much greater than that of sleB mutant spores. The roles of the sleB and cwlJ mutations in germination and spore maturation are also discussed. PMID:9515903

Mycoheterotrophic germination of Pyrola asarifolia dust seeds reveals convergences with germination in orchids.

PubMed

Hashimoto, Yasushi; Fukukawa, Satoru; Kunishi, Ayako; Suga, Haruhisa; Richard, Franck; Sauve, Mathieu; Selosse, Marc-André

2012-08-01

Dust seeds that germinate by obtaining nutrients from symbiotic fungi have evolved independently in orchids and 11 other plant lineages. The fungi involved in this 'mycoheterotrophic' germination have been identified in some orchids and non-photosynthetic Ericaceae, and proved identical to mycorrhizal fungi of adult plants. We investigated a third lineage, the Pyroleae, chlorophyllous Ericaceae species whose partial mycoheterotrophy at adulthood has recently attracted much attention. We observed experimental Pyrola asarifolia germination at four Japanese sites and investigated the germination pattern and symbiotic fungi, which we compared to mycorrhizal fungi of adult plants. Adult P. asarifolia, like other Pyroleae, associated with diverse fungal species that were a subset of those mycorrhizal on surrounding trees. Conversely, seedlings specifically associated with a lineage of Sebacinales clade B (endophytic Basidiomycetes) revealed an intriguing evolutionary convergence with orchids, some of which also germinate with Sebacinales clade B. Congruently, seedlings clustered spatially together, but not with adults. This unexpected transition in specificity and ecology of partners could support the developmental transition from full to partial mycoheterotrophy, but probably challenges survival and distribution during development. We discuss the physiological and ecological traits that predisposed to the repeated recruitment of Sebacinales clade B for dust seed germination. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Dormancy and germination: How does the crop seed decide?

PubMed

Shu, K; Meng, Y J; Shuai, H W; Liu, W G; Du, J B; Liu, J; Yang, W Y

2015-11-01

Whether seeds germinate or maintain dormancy is decided upon through very intricate physiological processes. Correct timing of these processes is most important for the plants life cycle. If moist conditions are encountered, a low dormancy level causes pre-harvest sprouting in various crop species, such as wheat, corn and rice, this decreases crop yield and negatively impacts downstream industrial processing. In contrast, a deep level of seed dormancy prevents normal germination even under favourable conditions, resulting in a low emergence rate during agricultural production. Therefore, an optimal seed dormancy level is valuable for modern mechanised agricultural systems. Over the past several years, numerous studies have demonstrated that diverse endogenous and environmental factors regulate the balance between dormancy and germination, such as light, temperature, water status and bacteria in soil, and phytohormones such as ABA (abscisic acid) and GA (gibberellic acid). In this updated review, we highlight recent advances regarding the molecular mechanisms underlying regulation of seed dormancy and germination processes, including the external environmental and internal hormonal cues, and primarily focusing on the staple crop species. Furthermore, future challenges and research directions for developing a full understanding of crop seed dormancy and germination are also discussed. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Glyphosate Can Decrease Germination of Glyphosate-Resistant Soybeans.

PubMed

Gomes, Marcelo Pedrosa; Bicalho, Elisa Monteze; Smedbol, Élise; Cruz, Fernanda Vieira da Silva; Lucotte, Marc; Garcia, Queila Souza

2017-03-22

We investigated the effects of different concentrations of glyphosate acid and one of its formulations (Roundup) on seed germination of two glyphosate-resistant (GR) and one non-GR variety of soybean. As expected, the herbicide affected the shikimate pathway in non-GR seeds but not in GR seeds. We observed that glyphosate can disturb the mitochondrial electron transport chain, leading to H 2 O 2 accumulation in soybean seeds, which was, in turn, related to lower seed germination. In addition, GR seeds showed increased activity of antioxidant systems when compared to non-GR seeds, making them less vulnerable to oxidative stress induced by glyphosate. The differences in the responses of GR varieties to glyphosate exposure corresponded to their differences in enzymatic activity related to H 2 O 2 scavenging and mitochondrial complex III (the proposed site of ROS induction by glyphosate). Our results showed that glyphosate ought to be used carefully as a pre-emergence herbicide in soybean field crop systems because this practice may reduce seed germination.

7 CFR 201.63 - Germination.

Code of Federal Regulations, 2010 CFR

2010-01-01

... germination and also to the sum of the germination plus the hard seed when 400 or more seeds are tested. Mean... 7 Agriculture 3 2010-01-01 2010-01-01 false Germination. 201.63 Section 201.63 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT...

7 CFR 201.63 - Germination.

Code of Federal Regulations, 2011 CFR

2011-01-01

... germination and also to the sum of the germination plus the hard seed when 400 or more seeds are tested. Mean... 7 Agriculture 3 2011-01-01 2011-01-01 false Germination. 201.63 Section 201.63 Agriculture..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT...

Effects of stress temperatures of germination on polyamine titers of soybean seeds

NASA Astrophysics Data System (ADS)

Pineda-Mejia, Renan

High and low stress temperatures during seed germination and seedling development limit total germination and the rate of germination and growth. Changes in polyamine (PA) concentrations in seeds of different species have been associated with germination, growth and environmental stresses such as temperature, drought, oxygen, chilling injury and osmotic conditions. Two studies were conducted to determine the effect of stress temperatures during germination and seedling development on polyamine titers in soybean seeds. Three germination temperatures, 25, 30, and 36°C were used in the first study to evaluate their influence on changes in polyamine concentrations in soybean seeds germinated at 76 and 90 hours. The polyamines (PAs), cadaverine (Cad), putrescine (Put), spermidine (Spd), agmatine (Agm), and spermine (Spin) were quantified by HPLC using a cation exchange column and an electrochemical detector. Cad, Put, Agm, and Spd declined as the germination temperatures increased from 25 to 36°C. Conversely, Spin increased considerably with an increase in temperature. Total germination was reduced from 97.2 to 92.5% as germination temperatures increased from 25 to 36°C. Germination time did not affect Cad, Agm and Spm, and total germination, however, the interaction between temperature and germination time for Put and Spd concentrations was significant. In the second study, changes in PA concentrations, seedling growth, germination time (t50), fresh and dry weight, and moisture content were measured in the embryonic axis and cotyledons of soybean seeds germinated at 10 and 25°C through six stages of germination dry seed (DS), testa split (TS), radicle at 10 mm (Ra-10), root hairs visible (RHV), secondary root primordia (SRP), and complete seedling (CS). The concentrations of Cad and Put in the embryonic axis, were significantly higher in seeds germinated under low temperature than in seeds at 25°C (approximately 10 and 3 fold respectively). However, this

S-nitrosylation triggers ABI5 degradation to promote seed germination and seedling growth

PubMed Central

Albertos, Pablo; Romero-Puertas, María C.; Tatematsu, Kiyoshi; Mateos, Isabel; Sánchez-Vicente, Inmaculada; Nambara, Eiji; Lorenzo, Oscar

2015-01-01

Plant survival depends on seed germination and progression through post-germinative developmental checkpoints. These processes are controlled by the stress phytohormone abscisic acid (ABA). ABA regulates the basic leucine zipper transcriptional factor ABI5, a central hub of growth repression, while the reactive nitrogen molecule nitric oxide (NO) counteracts ABA during seed germination. However, the molecular mechanisms by which seeds sense more favourable conditions and start germinating have remained elusive. Here we show that ABI5 promotes growth via NO, and that ABI5 accumulation is altered in genetic backgrounds with impaired NO homeostasis. S-nitrosylation of ABI5 at cysteine-153 facilitates its degradation through CULLIN4-based and KEEP ON GOING E3 ligases, and promotes seed germination. Conversely, mutation of ABI5 at cysteine-153 deregulates protein stability and inhibition of seed germination by NO depletion. These findings suggest an inverse molecular link between NO and ABA hormone signalling through distinct posttranslational modifications of ABI5 during early seedling development. PMID:26493030

Effect of canopy position on germination and seedling survival of epiphytic bromeliads in a Mexican humid montane forest.

PubMed

Winkler, Manuela; Hülber, Karl; Hietz, Peter

2005-05-01

Seeds of epiphytes must land on branches with suitable substrates and microclimates to germinate and for the resulting seedlings to survive. It is important to understand the fate of seeds and seedlings in order to model populations, but this is often neglected when only established plants are included in analyses. The seeds of five bromeliad species were exposed to different canopy positions in a Mexican montane forest, and germination and early seedling survival were recorded. Additionally, the survival of naturally dispersed seedlings was monitored in a census over 2.5 years. Survival analysis, a procedure rarely used in plant ecology, was used to study the influence of branch characteristics and light on germination and seedling survival in natural and experimental populations. Experimental germination percentages ranged from 7.2 % in Tillandsia deppeana to 33.7 % in T. juncea, but the seeds of T. multicaulis largely failed to germinate. Twenty months after exposure between 3.5 and 9.4 % of the seedlings were still alive. There was no evidence that canopy position affected the probability of germination, but time to germination was shorter in less exposed canopy positions indicating that higher humidity accelerates germination. More experimental seedlings survived when canopy openness was high, whereas survival in census-seedlings was influenced by moss cover. While mortality decreased steadily with age in juveniles of the atmospheric Tillandsia, in the more mesomorphic Catopsis sessiliflora mortality increased dramatically in the dry season. Seedling mortality, rather than the failure to germinate, accounts for the differential distribution of epiphytes within the canopy studied. With few safe sites to germinate and high seedling mortality, changes of local climate may affect epiphyte populations primarily through their seedling stage.

Portable Diagnostics and Rapid Germination

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

Dunn, Zachary Spencer

In the Bioenergy and Defense Department of Sandia National Laboratories, characterization of the BaDx (Bacillus anthracis diagnostic cartridge) was performed and rapid germination chemistry was investigated. BaDx was tested with complex sample matrixes inoculated with Bacillus anthracis, and the trials proved that BaDx will detect Bacillus anthracis in a variety of the medium, such as dirt, serum, blood, milk, and horse fluids. The dimensions of the device were altered to accommodate an E. coli or Listeria lateral flow immunoassay, and using a laser printer, BaDx devices were manufactured to identify E. coli and Listeria. Initial testing with E. coli versionsmore » of BaDx indicate that the device will be viable as a portable diagnostic cartridge. The device would be more effective with faster bacteria germination; hence studies were performed the use of rapid germination chemistry. Trials with calcium dipicolinic acid displayed increased cell germination, as shown by control studies using a microplate reader. Upon lyophilization the rapid germination chemistry failed to change growth patterns, indicating that the calcium dipicolinic acid was not solubilized under the conditions tested. Although incompatible with the portable diagnostic device, the experiments proved that the rapid germination chemistry was effective in increasing cell germination.« less

Phylogeny, habitat together with biological and ecological factors can influence germination of 36 subalpine Rhododendron species from the eastern Tibetan Plateau.

PubMed

Wang, Yongji; Lai, Liming; Du, Hui; Jiang, Lianhe; Wang, Fei; Zhang, Chao; Zhuang, Ping; Zheng, Yuanrun

2018-04-01

The reproductive stages of the life cycle are crucial in explaining the distribution patterns of plant species because of their extreme vulnerability to environmental conditions. Despite reported evidence that seed germination is related to habitat macroclimatic characteristics, such as mean annual temperature, the effect of this trait in controlling plant species distribution has not yet been systematically and quantitatively evaluated. To learn whether seed germination can predict species distribution along altitude gradients, we examined germination data of 36 Rhododendron species in southeastern Tibet originating from contrasting altitudes, habitats, plant heights, seed masses, and phylogenies. Germination varied significantly with altitude, habitat, plant height, and phylogeny and was higher in the light than in the dark. Germination percentage was highest at 10:20°C in the light and 15:25°C in the dark. As altitude increased, germination percentages first rose and then decreased, being highest at 3,500-4,000 m. Germination percentage and rate were highest on rocky slopes, increasing as seed mass and plant height rose. Variations in germination percentage and rate were not significant at subgenera, section, and subsection levels, but they were significant at species level. The results suggested that the relationship between germination and altitude may provide insights into species distribution patterns. Further, germination patterns are a result of long-term evolution as well as taxonomic constraints.

Phytotoxic effects of Sicyos deppei (Cucurbitaceae) in germinating tomato seeds.

PubMed

Lara-Núñez, Aurora; Sánchez-Nieto, Sobeida; Luisa Anaya, Ana; Cruz-Ortega, Rocio

2009-06-01

The phytotoxic effect of allelochemicals is referred to as allelochemical stress and it is considered a biotic stress. Sicyos deppei G. Don (Cucurbitaceae) is an allelopathic weed that causes phytotoxicity in Lycopersicon esculentum, delaying seed germination and severely inhibiting radicle growth. This paper reports in in vitro conditions, the effects of the aqueous leachate of S. deppei-throughout tomato germination times-on (1) the dynamics of starch and sugars metabolism, (2) activity and expression of the cell wall enzymes involved in endosperm weakening that allows the protrusion of the radicle, and (3) whether abscisic acid (ABA) is involved in this altered metabolic processes. Results showed that S. deppei leachate on tomato seed germination mainly caused: (1) delay in starch degradation as well as in sucrose hydrolysis; (2) lower activity of sucrose phosphate synthase, cell wall invertase, and alpha-amylase; being sucrose phosphate synthase (SPS) gene expression down-regulated, and the last two up regulated; (3) also, lower activity of endo beta-mannanase, beta-1,3 glucanase, alpha-galactosidase, and exo-polygalacturonase with altered gene expression; and (4) higher content of ABA during all times of germination. The phytotoxic effect of S. deppei aqueous leachate is because of the sum of many metabolic processes affected during tomato seed germination that finally is evidenced by a strong inhibition of radicle growth.

Comparison of germination and seed vigor of sunflower in two contaminated soils of different texture

NASA Astrophysics Data System (ADS)

Zhao, Xin; Han, Jaemaro; Lee, Jong Keun; Kim, Jae Young

2014-05-01

Phytoremediation as an emerging low-cost and ecologically friendly alternative to the conventional soil remediation technologies has gained a great deal of attention and into lots of research. As a kind of the methods that use of green plants to remediate heavy metals contaminated soils, the early growth status of plant seeds in the contaminated environmental directly affects the effect of phytoremediation. Germination test in the water (aqueous solution of heavy metal) is generally used for assessing heavy metal phytotoxicity and possibility of plant growth, but there is a limit. Because soil is commonly main target of phytoremediation, not the water. The bioavailability of heavy metals in the soil also depends on the texture. So soil texture is an important factor of phytoremediation effect. Sunflower is the representative species which have good tolerance to various heavy metals; furthermore, the seeds of sunflower can be used as the raw-material for producing bio-diesel. The objectives of this research were to investigate germination rate of sunflowers in various heavy metal contaminated soils and to compare the seedling vigor index (SVI) of sunflower in two contaminated soils of different texture. Sunflower (Helianthusannuus L.) seeds were obtained from a commercial market. In order to prove the soil texture effect on heavy metal contaminated soil, germination tests in soil were conducted with two different types of soil texture (i.e., loam soil and sandy loam soil) classified by soil textural triangle (defined by USDA) including representative soil texture of Korea. Germination tests in soil were conducted using KS I ISO 11260-1 (2005) for reference that sunflower seeds were incubated for 7 days in dark at 25 ± 1 Celsius degree. The target heavy metals are Nickel (Ni) and Zinc (Zn). The Ni and Zn concentrations were 0, 10, 50, 100, 200, 300, 500 mg-Ni/kg-dry soil, and 0, 10, 50, 100, 300, 500, 900 mg-Zn/kg-dry soil, respectively. After germination test for 7

Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals

PubMed Central

Tuan, Pham A.; Kumar, Rohit; Rehal, Pawanpuneet K.; Toora, Parneet K.; Ayele, Belay T.

2018-01-01

Seed dormancy is an adaptive trait that does not allow the germination of an intact viable seed under favorable environmental conditions. Non-dormant seeds or seeds with low level of dormancy can germinate readily under optimal environmental conditions, and such a trait leads to preharvest sprouting, germination of seeds on the mother plant prior to harvest, which significantly reduces the yield and quality of cereal crops. High level of dormancy, on the other hand, may lead to non-uniform germination and seedling establishment. Therefore, intermediate dormancy is considered to be a desirable trait as it prevents the problems of sprouting and allows uniformity of postharvest germination of seeds. Induction, maintenance, and release of seed dormancy are complex physiological processes that are influenced by a wide range of endogenous and environmental factors. Plant hormones, mainly abscisic acid (ABA) and gibberellin (GA), are the major endogenous factors that act antagonistically in the control of seed dormancy and germination; ABA positively regulates the induction and maintenance of dormancy, while GA enhances germination. Significant progress has been made in recent years in the elucidation of molecular mechanisms regulating ABA/GA balance and thereby dormancy and germination in cereal seeds, and this review summarizes the current state of knowledge on the topic. PMID:29875780

Effects of three fire-suppressant foams on the germination and physiological responses of plants.

PubMed

Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

2014-10-01

Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

Effects of Three Fire-Suppressant Foams on the Germination and Physiological Responses of Plants

NASA Astrophysics Data System (ADS)

Song, Uhram; Mun, Saeromi; Waldman, Bruce; Lee, Eun Ju

2014-10-01

Suppressant foams used to fight forest fires may leave residual effects on surviving biota that managers need to consider prior to using them. We examined how three fire-suppressant foams (FSFs) (Forexpan S, Phos-Chek-WD881, and Silv-ex) affected seed germination and physiological responses of three plant species. Exposure to FSFs, whether in diluted concentrations or those typical in the field, reduced final germination percentages of seeds grown in petri dishes and within growth chambers. However, the FSFs did not cause total germination failure in any treatment. Inhibition of germination increased with longer exposure times, but only to diluted FSF solutions. Unlike in the laboratory experiments, none of the three FSFs affected seedling emergence when tested in field conditions. Further, we found no evidence of long-term phytotoxic effects on antioxidant enzyme activity nor chlorophyll content of the plant saplings. Therefore, although the three FSFs showed evidence of phytotoxicity to plants in laboratory tests, their actual impact on terrestrial ecosystems may be minimal. We suggest that the benefits of using these FSFs to protect plants in threatened forest ecosystems outweigh their minor risks.

Within-and among-year germination in Sonoran Desert winter annuals: bet hedging and predictive germination in a variable environment.

PubMed

Gremer, Jennifer R; Kimball, Sarah; Venable, D Lawrence

2016-10-01

In variable environments, organisms must have strategies to ensure fitness as conditions change. For plants, germination can time emergence with favourable conditions for later growth and reproduction (predictive germination), spread the risk of unfavourable conditions (bet hedging) or both (integrated strategies). Here we explored the adaptive value of within- and among-year germination timing for 12 species of Sonoran Desert winter annual plants. We parameterised models with long-term demographic data to predict optimal germination fractions and compared them to observed germination. At both temporal scales we found that bet hedging is beneficial and that predicted optimal strategies corresponded well with observed germination. We also found substantial fitness benefits to varying germination timing, suggesting some degree of predictive germination in nature. However, predictive germination was imperfect, calling for some degree of bet hedging. Together, our results suggest that desert winter annuals have integrated strategies combining both predictive plasticity and bet hedging. © 2016 John Wiley & Sons Ltd/CNRS.

Physical characterization of Rhipsalis (Cactaceae) fruits and seeds germination in different temperatures and light regimes.

PubMed

Lone, A B; Colombo, R C; Andrade, B L G; Takahashi, L S A; Faria, R T

2016-06-01

The germination characteristics of the native cactus species are poorly known, being the temperature and the light the factors that the most interferes in that process. Thus, the objective of the present work was to characterize the fruits and evaluate the influence of the temperature and the light in the seed germination of Rhipsalis floccosa, Rhipsalis pilocarpa and Rhipsalis teres. The tested constant temperatures were 15, 20, 25, 30 and 35 °C and the alternate of 20-30 °C and 25-35 °C in a photoperiod of 10 hours, and with determination of the most appropriate temperature, the germination was tested in light absence. The germination percentage, the index of germination speed and medium time of germination were evaluated. For R. floccosa, the highest germination percentage was at 20 °C. For R. pilocarpa and R. teres, the highest germination percentages occurred in 15 °C and 20 °C. There was correlation to germination percentage between the three species, indicating that they had similar germination behavior. Total absence of germination was verified for the three species in condition of light absence. In conclusion, the temperature of 20 °C is the most suitable for the seed germination of R. floccosa. For the species R. pilocarpa and R. teres, the temperatures of 15 and 20 °C are the most suitable.

Effects of water level, shade and time on germination and growth of freshwater marsh plants along a simulated successional gradient

USGS Publications Warehouse

Kellogg, C.H.; Bridgham, S.D.; Leicht, S.A.

2003-01-01

1. We examined the effect of soil organic content (1.4, 3.6, 7.2% soil C), water level (+2, -1, -4 cm from soil surface) and duration (13 or 33 days) on 10 species that varied in abundance during succession in freshwater marshes. We also determined the effect of shade (0, 40, 80% shade) and soil organic content (1.4 and 7.2% soil C) on germination of six species over 62 days with water 0.5 cm below the soil surface. 2. Water level consistently affected species germination on both dates. Above-ground biomass was generally higher with increasing organic content of soil, but shade had little effect on germination or height. 3 The hydrologic zone in which species were found in the field was a good indicator of the response of germination to hydrology. Both early successional species and species wide-spread across the successional gradient show similar germination on all organic contents, while later successional species appear to germinate best at higher organic contents. 4. Successional changes in soils are capable of affecting plant community development, independent of disturbance.

Label-free in situ imaging of oil body dynamics and chemistry in germination

PubMed Central

Waschatko, Gustav; Billecke, Nils; Schwendy, Sascha; Jaurich, Henriette; Bonn, Mischa; Vilgis, Thomas A.

2016-01-01

Plant oleosomes are uniquely emulsified lipid reservoirs that serve as the primary energy source during seed germination. These oil bodies undergo significant changes regarding their size, composition and structure during normal seedling development; however, a detailed characterization of these oil body dynamics, which critically affect oil body extractability and nutritional value, has remained challenging because of a limited ability to monitor oil body location and composition during germination in situ. Here, we demonstrate via in situ, label-free imaging that oil bodies are highly dynamic intracellular organelles that are morphologically and biochemically remodelled extensively during germination. Label-free, coherent Raman microscopy (CRM) combined with bulk biochemical measurements revealed the temporal and spatial regulation of oil bodies in native soya bean cotyledons during the first eight days of germination. Oil bodies undergo a cycle of growth and shrinkage that is paralleled by lipid and protein compositional changes. Specifically, the total protein concentration associated with oil bodies increases in the first phase of germination and subsequently decreases. Lipids contained within the oil bodies change in saturation and chain length during germination. Our results show that CRM is a well-suited platform to monitor in situ lipid dynamics and local chemistry and that oil bodies are actively remodelled during germination. This underscores the dynamic role of lipid reservoirs in plant development. PMID:27798279

Use of a germination bioassay to test compost maturity in Tekelan Village

NASA Astrophysics Data System (ADS)

Oktiawan, Wiharyanto; Zaman, Badrus; Purwono

2018-02-01

Livestock waste from cattle farms in Tekelan village, Getasan Subdistrict, Semarang Regency can be grouped into three types, namely solid waste, slurry and waste water. Solid waste (cow dung) was processed into compost, while slurry and waste water were used to make liquid fertilizer. This compost was used as a component of planting media in horticultural crops and potted plants production. We evaluated the toxicity (phytochemical and ecotoxicological) test of compost by using germination index (GI). Vigna radiata seeds are sown on filter paper dampened with compost extract for different times. GI was calculated by relative germination (G) and relative radical length (L). The germination index (GI) = G / G0 x L / L0 x 100, where G0 and L0 are values obtained by distilled water as a control. The results showed that germination bioassay and radical length using aquades and groundwater in Tekelan village did not affect the radical length of Vigna radiata . Technically, groundwater in Tekelan village can be used as a germination bioassay control. The cow dung compost substrate appears to have a major influence on compost toxicity. Mature compost was produced on day 14 with a GI of 104.03.

[The research of Valeriana amurensis seed germination characteristics].

PubMed

Liu, Juan; Yang, Chun-Rong; Jiang, Bo; Fang, Min; Du, Juan

2011-10-01

To study the effect of different treatments on the Valeriana amurensis seed germination rate. Used different chemical reagents and seed soakings on the routine germination test and the orthogonal test of the Valeriana amurensis seed, calculated the germination rate under different germination condition. Valeriana amurensis treated with different chemical reagends had different germination rate. The suitable immersion time could enhance Valeriana amurensis seed germination rate. Different treatment time, different disposal temperature, different germination temperature would have an impact on the Valeriana amurensis seed germination rate. In order to raise the Valeriana amurensis seed germination rate, use appropriate treatment on the seed before plant seeds; The seed growing must under suitable time and temperature.

Higher Temperature at Lower Elevation Sites Fails to Promote Acclimation or Adaptation to Heat Stress During Pollen Germination.

PubMed

Flores-Rentería, Lluvia; Whipple, Amy V; Benally, Gilbert J; Patterson, Adair; Canyon, Brandon; Gehring, Catherine A

2018-01-01

High temperatures associated with climate change are expected to be detrimental for aspects of plant reproduction, such as pollen viability. We hypothesized that (1) higher peak temperatures predicted with climate change would have a minimal effect on pollen viability, while high temperatures during pollen germination would negatively affect pollen viability, (2) high temperatures during pollen dispersal would facilitate acclimation to high temperatures during pollen germination, and (3) pollen from populations at sites with warmer average temperatures would be better adapted to high temperature peaks. We tested these hypotheses in Pinus edulis , a species with demonstrated sensitivity to climate change, using populations along an elevational gradient. We tested for acclimation to high temperatures by measuring pollen viability during dispersal and germination stages in pollen subjected to 30, 35, and 40°C in a factorial design. We also characterized pollen phenology and measured pollen heat tolerance using trees from nine sites along a 200 m elevational gradient that varied 4°C in temperature. We demonstrated that this gradient is biologically meaningful by evaluating variation in vegetation composition and P. edulis performance. Male reproduction was negatively affected by high temperatures, with stronger effects during pollen germination than pollen dispersal. Populations along the elevational gradient varied in pollen phenology, vegetation composition, plant water stress, nutrient availability, and plant growth. In contrast to our hypothesis, pollen viability was highest in pinyons from mid-elevation sites rather than from lower elevation sites. We found no evidence of acclimation or adaptation of pollen to high temperatures. Maximal plant performance as measured by growth did not occur at the same elevation as maximal pollen viability. These results indicate that periods of high temperature negatively affected sexual reproduction, such that even high pollen

Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions

PubMed Central

Meng, Yongjie; Chen, Feng; Shuai, Haiwei; Luo, Xiaofeng; Ding, Jun; Tang, Shengwen; Xu, Shuanshuan; Liu, Jianwei; Liu, Weiguo; Du, Junbo; Liu, Jiang; Yang, Feng; Sun, Xin; Yong, Taiwen; Wang, Xiaochun; Feng, Yuqi; Shu, Kai; Yang, Wenyu

2016-01-01

Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interestingly, KAR only retarded soybean seed germination under shaded conditions, rather than under dark and white light conditions, which differs from in Arabidopsis. Phytohormone quantification showed that KAR enhanced ABA biogenesis while impairing GA biosynthesis during the seed imbibition process, and subsequently, the ratio of active GA4 to ABA was significantly reduced. Further qRT-PCR analysis showed that the transcription pattern of genes involved in ABA and GA metabolic pathways are consistent with the hormonal measurements. Finally, fluridone, an ABA biogenesis inhibitor, remarkably rescued the delayed-germination phenotype of KAR-treatment; and paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Taken together, these evidences suggest that KAR inhibit soybean seed germination by mediating the ratio between GA and ABA biogenesis. PMID:26902640

Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions.

PubMed

Meng, Yongjie; Chen, Feng; Shuai, Haiwei; Luo, Xiaofeng; Ding, Jun; Tang, Shengwen; Xu, Shuanshuan; Liu, Jianwei; Liu, Weiguo; Du, Junbo; Liu, Jiang; Yang, Feng; Sun, Xin; Yong, Taiwen; Wang, Xiaochun; Feng, Yuqi; Shu, Kai; Yang, Wenyu

2016-02-23

Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interestingly, KAR only retarded soybean seed germination under shaded conditions, rather than under dark and white light conditions, which differs from in Arabidopsis. Phytohormone quantification showed that KAR enhanced ABA biogenesis while impairing GA biosynthesis during the seed imbibition process, and subsequently, the ratio of active GA4 to ABA was significantly reduced. Further qRT-PCR analysis showed that the transcription pattern of genes involved in ABA and GA metabolic pathways are consistent with the hormonal measurements. Finally, fluridone, an ABA biogenesis inhibitor, remarkably rescued the delayed-germination phenotype of KAR-treatment; and paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Taken together, these evidences suggest that KAR inhibit soybean seed germination by mediating the ratio between GA and ABA biogenesis.

Germination response in wheat grains to dihydroactinidiolide, a germination inhibitor in wheat husks, and related compounds.

PubMed

Kato, Tadahiro; Imai, Takahito; Kashimura, Kaori; Saito, Naoko; Masaya, Kengo

2003-04-09

On the basis of our recent findings that the germination of intact wheat grains with glumes (husks) belonging to dormant varieties was restrained as compared with that of dehusked grains, we have explored the identities of germination inhibitors in the glumes, resulting in the characterization of dihydroactinidiolide (1) and some aromatic compounds. A related natural product, tetrahydroactinidiolide (2), showed similar activity. The present study has demonstrated that the sensitivity in inhibition response of germination of the grains to 1 and 2 declined during after-ripening, in parallel with changes in germinability; the sprouting of after-ripened seeds on a whole spike was preventable by exogenous application of 2 in laboratory conditions, and germination of after-ripened grains was delayed by more than two weeks by the action of 1 or 2. The term "pseudodormancy" is proposed for the phenomenon of delay of germination caused by the inhibitor. After accumulation of additional evidence on inhibition response of actinidiolide-type natural products, structurally related to inhibitor 1, a mechanism concerning germination inhibition by 1 or 2 is proposed on the basis of the concept of nonbonding interaction with the inhibitors at an active site of an acceptor.

Effect of Canopy Position on Germination and Seedling Survival of Epiphytic Bromeliads in a Mexican Humid Montane Forest

PubMed Central

WINKLER, MANUELA; HÜLBER, KARL; HIETZ, PETER

2005-01-01

• Background and Aims Seeds of epiphytes must land on branches with suitable substrates and microclimates to germinate and for the resulting seedlings to survive. It is important to understand the fate of seeds and seedlings in order to model populations, but this is often neglected when only established plants are included in analyses. • Methods The seeds of five bromeliad species were exposed to different canopy positions in a Mexican montane forest, and germination and early seedling survival were recorded. Additionally, the survival of naturally dispersed seedlings was monitored in a census over 2·5 years. Survival analysis, a procedure rarely used in plant ecology, was used to study the influence of branch characteristics and light on germination and seedling survival in natural and experimental populations. • Key Results Experimental germination percentages ranged from 7·2 % in Tillandsia deppeana to 33·7 % in T. juncea, but the seeds of T. multicaulis largely failed to germinate. Twenty months after exposure between 3·5 and 9·4 % of the seedlings were still alive. There was no evidence that canopy position affected the probability of germination, but time to germination was shorter in less exposed canopy positions indicating that higher humidity accelerates germination. More experimental seedlings survived when canopy openness was high, whereas survival in census-seedlings was influenced by moss cover. While mortality decreased steadily with age in juveniles of the atmospheric Tillandsia, in the more mesomorphic Catopsis sessiliflora mortality increased dramatically in the dry season. • Conclusions Seedling mortality, rather than the failure to germinate, accounts for the differential distribution of epiphytes within the canopy studied. With few safe sites to germinate and high seedling mortality, changes of local climate may affect epiphyte populations primarily through their seedling stage. PMID:15767270

High Pressure Germination of Bacillus subtilis Spores with Alterations in Levels and Types of Germination Proteins

DTIC Science & Technology

2014-01-01

a rapidly growing non thermal food processing technology that ensures the safety of meat, fruit juice and seafood products, extends product shelf...spore germination with nutrient germinants are the sum of values for germination via the GerA GR with L valine and the GerB plus GerK GRs with AGFK...gerKD had no significant effect on mHP germination (Fig. 1d). Complementation of a gerKD strain by introduction of a wild type gerKD gene plus its own

Internal dispersal of seeds by waterfowl: effect of seed size on gut passage time and germination patterns

NASA Astrophysics Data System (ADS)

Figuerola, Jordi; Charalambidou, Iris; Santamaria, Luis; Green, Andy J.

2010-06-01

Long distance dispersal may have important consequences for gene flow and community structure. The dispersal of many plants depends on transport by vertebrate seed dispersers. The shapes of seed shadows produced by vertebrates depend both on movement patterns of the dispersers and on the dynamics and effects of passage through the disperser’s gut (i.e. the retention time, survival and germination of ingested seeds). A combination of experiments with captive waterbirds and aquatic plant seeds was used to analyse the following: (a) the effects of inter- and intra-specific variation in seed size and duck species on seed retention time in the gut and (b) the relationship between retention time and the percent germination and germination rates of seeds. Among the three Scirpus species used, those with smaller seeds showed higher survival after ingestion by birds and longer retention times inside their guts than those with larger seeds. For Potamogeton pectinatus, only seeds from the smaller size class (<8 mg) survived ingestion. Retention time affected the percent germination and germination rate of Scirpus seeds but in a manner that varied for the different plant and bird species studied. We recorded both linear and non-linear effects of retention time on percent germination. In addition, germination rate was positively correlated with retention time in Scirpus litoralis but negatively correlated in Scirpus lacustris. Small seed size can favour dispersal over larger distances. However, the effects of retention time on percent germination can modify the seed shadows produced by birds due to higher percent germination of seeds retained for short or intermediate periods. The changes in dispersal quality associated with dispersal distance (which is expected to be positively related to retention time) will affect the probability of seedling establishment over longer distances and, thus, the spatial characteristics of the effective seed shadow.

Seed development and viviparous germination in one accession of a tomato rin mutant

PubMed Central

Wang, Xu; Zhang, Lili; Xu, Xiaochun; Qu, Wei; Li, Jingfu; Xu, Xiangyang; Wang, Aoxue

2016-01-01

In an experimental field, seed vivipary occurred in one accession of tomato rin mutant fruit at approximately 45–50 days after pollination (DAP). In this study, the possible contributory factors to this viviparous germination were investigated. Firstly, developing seeds were freshly excised from the fruit tissue every 5 days from 25–60 DAP. Germination occurred when isolated seeds were incubated on water, but was inhibited when they remained ex situ in fruit mucilage gel. The effect of abscisic acid (ABA) and osmoticum, separate and together, on germination of developing seeds was investigated. Additionally, ABA content in the seed and mucilage gel, as well as fruit osmolality were measured. The results showed that ABA concentrations in seeds were low during early development and increased later, peaking at about 50 DAP. ABA concentrations in rin accession were similar to those of the control cultivar and thus are not directly associated with the occurrence of vivipary. Developing seeds of rin accession are more sensitive than control seeds to all inhibitory compounds. However, osmolality in rin fruit at later developmental stages becomes less negative that is required to permit germination of developing seeds. Hence, hypo-osmolality in rin fruit may be an important factor in permitting limited viviparous germination. PMID:27436947

Dipicolinic Acid Release and the Germination of Alicyclobacillus acidoterrestris Spores under Nutrient Germinants.

PubMed

Porębska, Izabela; Sokołowska, Barbara; Woźniak, Łukasz

2017-03-30

The presence of Alicyclobacillus, a thermoacidophilic and spore-forming bacterium, in acidic fruit juices poses a serious problem for the processing industry. A typical sign of spoilage in contaminated juices is a characteristic phenolic off-flavour associated with the production of guaiacol. Spores are formed in response to starvation and in a natural environment re-access the nutrients, e.g.: L-alanine and AGFK - a mixture of asparagine, glucose, fructose and potassium, triggers germination. The aim of this study was to estimate the impact of L-alanine and AGFK on the germination of the spores of two Alicyclobacillus acidoterrestris strains and to evaluate the relationship of the germination rate with dipicolinic acid (DPA) release. The spores were suspended in apple juice or in buffers at pH 4 and pH 7, followed by the addition of L-alanine and AGFK. Suspensions were or were not subjected, to a temperature of 80°C/10 min and incubated for various periods of time at 45°C. Optical density (OD660) was used to estimate the number of germinated spores. The amount of DPA released was determined using HPLC. The results indicate that the degree of germination of A. acidoterrestris spores depended on the strain and time of incubation and the nutritious compounds used. The data obtained show that the amount of DPA released correlated to the number of A. acidoterrestris spores germinated.

On Teaching the Scientific Complexity of Germination: A Study with Prospective Elementary Teachers

ERIC Educational Resources Information Center

Vidal, Manuel; Membiela, Pedro

2014-01-01

This study reveals and discusses the problems of future elementary teachers after they have completed a practical on germination, including the fact that such practice is conceptually more complex than is usually considered, at least when the aim is to experiment with the determinant factors for germination. In this case there seemed to be some…

The role of fleshy pericarp in seed germination and dispersal under flooded conditions in three wetland forest species

NASA Astrophysics Data System (ADS)

Mora, Juan P.; Smith-Ramírez, Cecilia; Zúñiga-Feest, Alejandra

2013-01-01

In flooded habitats, inundations affect important forest regeneration processes, such as seed dispersal and germination. The main seed dispersal mechanism used by species in Austral South American temperate swamp and riparian forests is endozoochory, which releases seeds from the fleshy pericarp. Endozoochory could be favorable or unfavorable in wetland habitats, since this mechanism exposes seeds directly to water and can, in some cases, be detrimental to germination. In this study, we studied whether or not the fleshy pericarp favors germination after the flooding period's end. Furthermore, we quantified if the number of days which the fruit was found to be floating related to its germination success. We used the seeds of three common fleshy fruit species of flooded habitats from southern Chile, the trees Luma apiculata and Rhaphithamnus spinosus, and the vine Luzuriaga radicans. We simulated flooding periods of 7, 15, 30 and 45 days submerging seeds, with and without pericarps, in water. We found that the pericarp's presence significantly increased Luma's germination success and significantly decreased that of Luzuriaga. The germination of Rhaphithamnus was low after periods of flooding in both seed treatments, with no significant differences found between them. The fruits could float for an average of one to four weeks, depending on the species, which did not relate to their germination success. These results show that germination was affected by the presence of fleshy pericarps in flooded conditions and furthermore, that flotation allows for hydrochory from one week to one month. We suggest that in swamp forests multiple seed dispersal mechanisms are advantageous, especially for fleshy-fruited species.

Toxicity screening of biochar-mineral composites using germination tests.

PubMed

Mumme, Jan; Getz, Josephine; Prasad, Munoo; Lüder, Ulf; Kern, Jürgen; Mašek, Ondřej; Buss, Wolfram

2018-05-08

This study assessed the properties and toxicity (water cress germination trials) of 38 waste-derived, novel biochar-mineral composites (BMCs) produced via slow pyrolysis and hydrothermal carbonization (hydrochars). The biochars were produced from sewage sludge and compost-like output (CLO) by varying the type of mineral additive (zeolite, wood ash and lignite fly ash), the mineral-to-feedstock ratio and the carbonization process. While pure hydrochars completely inhibited germination of water cress, this effect was ameliorated by mineral additives. Seedlings grew best in pyrolysis chars and while wood ash addition decreased plant growth in many cases, 1:10 addition to CLO doubled germination rate. The factors responsible for the phytotoxicity can be attributed to pH, salinity and organic contaminants. Importantly, while pure minerals inhibited germination, conversion of minerals into BMCs reduced their inhibitory effects due to buffered release of minerals. Overall, mineral wastes (e.g., combustion ashes) and waste biomass can be used safely as sources of nutrients and stable organic carbon (for soil carbon sequestration) when converted into specific biochar-mineral composites, exploiting synergies between the constituents to deliver superior performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Activation of maturation promoting factor in Bufo arenarum oocytes: injection of mature cytoplasm and germinal vesicle contents.

PubMed

Toranzo, G Sánchez; Bonilla, F; Zelarayán, L; Oterino, J; Bühler, M I

2006-11-01

Although progesterone is the established maturation inducer in amphibians, Bufo arenarum oocytes obtained during the reproductive period (spring-summer) resume meiosis with no need of an exogenous hormonal stimulus if deprived of their enveloping follicle cells, a phenomenon called spontaneous maturation. In this species it is possible to obtain oocytes competent and incompetent to undergo spontaneous maturation according to the seasonal period in which animals are captured. Reinitiation of meiosis is regulated by maturation promoting factor (MPF), a complex of the cyclin-dependent kinase p34cdc2 and cyclin B. Although the function and molecule of MPF are common among species, the formation and activation mechanisms of MPF differ according to species. This study was undertaken to evaluate the presence of pre-MPF in Bufo arenarum oocytes incompetent to mature spontaneously and the effect of the injection of mature cytoplasm or germinal vesicle contents on the resumption of meiosis. The results of our treatment of Bufo arenarum immature oocytes incompetent to mature spontaneously with sodium metavanadate (NaVO3) and dexamethasone (DEX) indicates that these oocytes have a pre-MPF, which activates and induces germinal vesicle breakdown (GVBD) by dephosphorylation on Thr-14/Tyr-15 by cdc25 phosphatase and without cyclin B synthesis. The injection of cytoplasm containing active MPF is sufficient to activate an amplification loop that requires the activation of cdc25 and protein kinase C, the decrease in cAMP levels, and is independent of protein synthesis. However, the injection of germinal vesicle content also induces GVBD in the immature receptor oocyte, a process dependent on protein synthesis but not on cdc25 phosphatase or PKC activity.

The effects of Fusarium oxysporum on broomrape (Orobanche egyptiaca) seed germination.

PubMed

Hasannejad, S; Zad, S Javad; Alizade, H Mohamad; Rahymian, H

2006-01-01

Broomrape (Orobanche aegyptiaca L.), one of the most important parasitic weeds in Iran, is a root parasitic plant that can attack several crops such as tobacco, sunflower, tomato and etc. Several methods were used for Orobanche control, however these methods are inefficient and very costly. Biological control is an additional recent tool for the control of parasitic weeds. In order to study of the fungus Fusarium oxysporum (biocontrol agent) effects on broomrape seed germination, two laboratory studies were conducted in Tehran University. In the first experiment, different concentration of GR60 (0, 1, 2 and 5 ppm) as stimulation factor for Orobanche seeds germination were experimented. Results showed that concentrations of GR60 had a significant effect on seed germination. The highest seed germination percent was obtained in 1 ppm. In the second experiment, the effect of Fusarium oxysporum was tested on O. aegyptiaca seeds germination. The fungus Fusarium oxysporum were isolated from infested and juvenile O. aegyptiaca ower stalks in tomato field in karaj. Fungus spores suspension in different concentrations (0 (Control), 10(5) (T1), 10(6) (T2), 10(7) (T3) and 3 x 10(7) (T4)) from potato dextrose agar (PDA) prepared and together with 1ppm of GR60 concentration were tested on O. aegyptiaca seeds. Results show that the highest inhibition of seed germination obtained in 10(5) spores/ml. With increasing of suspension concentrations, inhibition percent was reduced and mortality of seeds germ tube was increased. In this investigation, Fusarium oxysporum can be used to inhibit seed germination, stimulate the "suicidal germination" of seeds and reduce the Orobanche seed bank.

Chcanges in Germinability and Activities of Polyphenol Oxidase and Peroxidase in Seeds of Pentaclethramacrophylla During Lowtemperature Treatment

NASA Astrophysics Data System (ADS)

Udosen, I. R.; Nkang, A. E.; Sam, S. M.

2012-07-01

Activities of peroxidase (POD) and polyphenol Oxidase (PPO) were investigated in seeds of Pentaclethramacrophylla during low temperature treatment. The seeds from the small-sized fruits (variety A) and those of the big-sized fruits (variety B) showed high germination, with maximum germination values ranging between 60 ñ 90%. Low temperature treatment did not significantly (P< 0.5) affect maximum germination values. Activities of POD and PPO increased initially (2-4 days) but declined with prolonged (6ñ8 days) low temperature treatment.

Memory of Germinant Stimuli in Bacterial Spores

PubMed Central

Wang, Shiwei; Faeder, James R.; Setlow, Peter

2015-01-01

ABSTRACT Bacterial spores, despite being metabolically dormant, possess the remarkable capacity to detect nutrients and other molecules in their environment through a biochemical sensory apparatus that can trigger spore germination, allowing the return to vegetative growth within minutes of exposure of germinants. We demonstrate here that bacterial spores of multiple species retain memory of transient exposures to germinant stimuli that can result in altered responses to subsequent exposure. The magnitude and decay of these memory effects depend on the pulse duration as well as on the separation time, incubation temperature, and pH values between the pulses. Spores of Bacillus species germinate in response to nutrients that interact with germinant receptors (GRs) in the spore’s inner membrane, with different nutrient types acting on different receptors. In our experiments, B. subtilis spores display memory when the first and second germinant pulses target different receptors, suggesting that some components of spore memory are downstream of GRs. Furthermore, nonnutrient germinants, which do not require GRs, exhibit memory either alone or in combination with nutrient germinants, and memory of nonnutrient stimulation is found to be more persistent than that induced by GR-dependent stimuli. Spores of B. cereus and Clostridium difficile also exhibit germination memory, suggesting that memory may be a general property of bacterial spores. These observations along with experiments involving strains with mutations in various germination proteins suggest a model in which memory is stored primarily in the metastable states of SpoVA proteins, which comprise a channel for release of dipicolinic acid, a major early event in spore germination. PMID:26604257

Plant germination and growth after exposure to iron cyanide complexes.

PubMed

Kang, Dong-Hee; Hong, Lee Y; Schwab, A Paul; Banks, M Katherine

2008-05-01

Phytoremediation has been proposed for treatment of cyanide-contaminated soil. This study was conducted to identify plants with the highest potential for phytoremediation of iron cyanide contaminated soil. Multiple cultivars of two cyanogenic species, sorghum (Sorghum bicolor) and flax (Linum usitatissimum), and one non-cyanogenic species, switchgrass (Panicum virgatum L), were selected for evaluation. The cultivars were screened by quantifying germination and root elongation. Differences in germination emerged among the cultivars (P < 0.05), but these differences appeared to be unrelated to cyanide concentration. The presence of 1000 mg/kg Prussian blue tended to suppress root growth parameters of flax and switchgrass but did not affect sorghum similarly.

The effect of the germination temperature on the phytochemical content of broccoli and rocket sprouts.

PubMed

Ragusa, Lucia; Picchi, Valentina; Tribulato, Alessandro; Cavallaro, Chiara; Lo Scalzo, Roberto; Branca, Ferdinando

2017-06-01

This study investigates the effect of different germination temperatures (10, 20 and 30 °C) on the phytochemical content as well as reducing and antioxidant capacity of broccoli and rocket sprouts. In both seeds and sprouts, the total glucosinolates and ascorbic acid contents did not differ between vegetables, while broccoli exhibited exceptionally higher polyphenols and greater reducing and antioxidant capacity compared to rocket. In both species, an increase in germination temperature positively affected the glucosinolate content. Ascorbic acid increased during germination without a difference among the three tested temperatures. The phenol content in broccoli sprouts increased when they were grown at 30 °C, but the amount decreased at the highest temperatures in rocket. The reducing and antioxidant capacities increased with germination, and higher indexes were detected at 10 °C, particularly in rocket. Different germination temperatures differentiate the health-promoting phytochemical content and antioxidant properties in broccoli and rocket sprouts.

Kinetics of Germination of Bacillus Spores1

PubMed Central

Vary, J. C.; Halvorson, H. O.

1965-01-01

Vary, J. C. (University of Wisconsin, Madison), and H. O. Halvorson. Kinetics or germination of Bacillus spores. J. Bacteriol. 89:1340–1347. 1965.—The kinetics of germination of Bacillus cereus strain T spores was accurately described by McCormick. To study the mechanism of germination, it is necessary to correlate the characteristic changes in a population of germinating spores with the behavior of the individual spores in the same population. Two microscopic events are apparent during germination: microlag, the time interval between the addition of l-alanine to heat-activated spores and the beginning of loss in refractility, and microgermination time, the time for the actual change in refractility to occur. The frequency distributions of both events are skewed, and appear to be independent. The effects of l-alanine concentration, heat activation, and temperature of germination on three parameters, microlag, microgermination, and per cent germination, were microscopically studied. The data are discussed in relation to the mechanism of germination, and a correlation between microlag and microgermination times with the constants of McCormick's equation has been suggested. Images PMID:14293008

Germination niche breadth varies inconsistently among three Asclepias congeners along a latitudinal gradient.

PubMed

Finch, Jessamine; Walck, Jeffrey L; Hidayati, Siti N; Kramer, Andrea T; Lason, Victoria; Havens, Kayri

2018-05-20

Species responses to climate change will be primarily driven by their environmental tolerance range, or niche breadth, with the expectation that broad niches will increase resilience. Niche breadth is expected to be greater in more heterogeneous environments and moderated by life history. Niche breadth also varies across life stage. Therefore, the life stage with the narrowest niche may serve as the best predictor of climatic vulnerability. To investigate the relationship between niche breadth, climate, and life stage we identify germination niche breadth for dormant and nondormant seeds in multiple populations of three milkweed (Asclepias) species. Complementary trials evaluated germination under conditions simulating historic and predicted future climate by varying cold-moist stratification temperature, length, and incubation temperature. Germination niche breadth was derived from germination evenness across treatments (Levins B n ), with stratified seeds considered less dormant than non-stratified seeds. Germination response varies significantly among species, populations, and treatments. Cold-moist stratification ≥ 4 weeks (1-3°C) followed by incubation at 25/15°C+ achieves peak germination for most populations. Germination niche breadth significantly expands following stratification and interacts significantly with latitude of origin. Interestingly, two species display a positive relationship between niche breadth and latitude, while the third presents a concave quadratic relationship. Germination niche breadth significantly varies by species, latitude, and population, suggesting an interaction between source climate, life history, and site-specific factors. Results contribute to our understanding of inter- and intraspecific variation in germination, underscore the role of dormancy in germination niche breadth, and have implications for prioritizing and conserving species under climate change. This article is protected by copyright. All rights reserved

Effect of salinity on tomato (Lycopersicon esculentum Mill.) during seed germination stage.

PubMed

Singh, Jogendra; Sastry, E V Divakar; Singh, Vijayata

2012-01-01

A study was conducted using ten genetically diverse genotypes along with their 45F1 (generated by diallel mating) under normal and salt stress conditions. Although, tomato (Lycopersicon esculentum Mill.) is moderately sensitive to salinity but more attention to salinity is yet to be required in the production of tomato. In present study, germination rate, speed of germination, dry weight ratio and Na(+)/K(+) ratio in root and shoot, were the parameters assayed on three salinity levels; control, 1.0 % NaCl and 3.0 % NaCl with Hoagland's solution. Increasing salt stress negatively affected growth and development of tomato. When salt concentration increased, germination of tomato seed was reduced and the time needed to complete germination lengthened, root/shoot dry weight ratio was higher and Na(+) content increased but K(+) content decreased. Among the varieties, Sel-7 followed by Arka Vikas and crosses involving them as a parent were found to be the more tolerant genotypes in the present study on the basis of studied parameters.

Karrikins discovered in smoke trigger Arabidopsis seed germination by a mechanism requiring gibberellic acid synthesis and light.

PubMed

Nelson, David C; Riseborough, Julie-Anne; Flematti, Gavin R; Stevens, Jason; Ghisalberti, Emilio L; Dixon, Kingsley W; Smith, Steven M

2009-02-01

Discovery of the primary seed germination stimulant in smoke, 3-methyl-2H-furo[2,3-c]pyran-2-one (KAR1), has resulted in identification of a family of structurally related plant growth regulators, karrikins. KAR1 acts as a key germination trigger for many species from fire-prone, Mediterranean climates, but a molecular mechanism for this response remains unknown. We demonstrate that Arabidopsis (Arabidopsis thaliana), an ephemeral of the temperate northern hemisphere that has never, to our knowledge, been reported to be responsive to fire or smoke, rapidly and sensitively perceives karrikins. Thus, these signaling molecules may have greater significance among angiosperms than previously realized. Karrikins can trigger germination of primary dormant Arabidopsis seeds far more effectively than known phytohormones or the structurally related strigolactone GR-24. Natural variation and depth of seed dormancy affect the degree of KAR1 stimulation. Analysis of phytohormone mutant germination reveals suppression of KAR1 responses by abscisic acid and a requirement for gibberellin (GA) synthesis. The reduced germination of sleepy1 mutants is partially recovered by KAR1, which suggests that germination enhancement by karrikin is only partly DELLA dependent. While KAR1 has little effect on sensitivity to exogenous GA, it enhances expression of the GA biosynthetic genes GA3ox1 and GA3ox2 during seed imbibition. Neither abscisic acid nor GA levels in seed are appreciably affected by KAR1 treatment prior to radicle emergence, despite marked differences in germination outcome. KAR1 stimulation of Arabidopsis germination is light-dependent and reversible by far-red exposure, although limited induction of GA3ox1 still occurs in the dark. The observed requirements for light and GA biosynthesis provide the first insights into the karrikin mode of action.

Zinnia Germination and Lunar Soil Amendment

NASA Technical Reports Server (NTRS)

Reese, Laura

2017-01-01

Germination testing was performed to determine the best method for germinating zinnias. This method will be used to attempt to germinate the zinnia seeds produced in space. It was found that seed shape may be critically important in determining whether a seed will germinate or not. The ability of compost and worm castings to remediate lunar regolith simulant for plant growth was tested. It was found that neither treatment effectively improves plant growth in lunar regolith simulant. A potential method of improving lunar regolith simulant by mixing it with arcillite was discovered.

Fluridone and norflurazon, carotenoid-biosynthesis inhibitors, promote seed conditioning and germination of the holoparasite Orobanche minor.

PubMed

Chae, Sang Heon; Yoneyama, Koichi; Takeuchi, Yasutomo; Joel, Daniel M.

2004-02-01

Fluridone and norflurazon, two carotenoid-biosynthesis inhibitors, shortened the conditioning period required by seeds of Orobanche minor in order to respond to the germination stimulant strigol. Neither fluridone nor norflurazon alone induced seed germination of O. minor, they promoted strigol-induced germination. In addition, these compounds restored the conditioning and germination of seeds at a supraoptimal temperature (30 degrees C) as well as in the light. Gibberellic acid (GA(3)) showed similar promotive and protective effects on the conditioning and germination of O. minor seeds. Although fluridone and norflurazon are known to prevent abscisic acid (ABA)-biosynthesis, and stresses such as supraoptimal temperatures have been reported to induce ABA accumulation in plants, the amount of ABA in the seeds or that released from the seeds into the conditioning media was not affected by the fluridone treatment and by exposure to the supraoptimal temperature. These results indicate that the promotive and protective effects of fluridone and norflurazon on the conditioning and germination of O. minor seeds would be attributed to other perturbations rather than the inhibition of ABA-biosynthesis.

The community-level effect of light on germination timing in relation to seed mass: a source of regeneration niche differentiation.

PubMed

Zhang, Chunhui; Willis, Charles G; Burghardt, Liana T; Qi, Wei; Liu, Kun; Souza-Filho, Paulo Roberto de Moura; Ma, Zhen; Du, Guozhen

2014-11-01

Within a community, species may germinate at different times so as to mitigate competition and to take advantage of different aspects of the seasonal environment (temporal niche differentiation). We illustrated a hypothesis of the combined effects of abiotic and biotic competitive factors on germination timing and the subsequent upscale effects on community assembly. We estimated the germination timing (GT) for 476 angiosperm species of the eastern Tibetan Plateau grasslands under two light treatments in the field: high (i.e. natural) light and low light. We also measured the shift in germination timing (SGT) across treatments for all species. Furthermore, we used phylogenetic comparative methods to test if GT and SGT were associated with seed mass, an important factor in competitive interactions. We found a significant positive correlation between GT and seed mass in both light treatments. Additionally, small seeds (early germinating seeds) tended to germinate later and large seeds (late germinating seeds) tended to germinate earlier under low light vs high light conditions. Low light availability can reduce temporal niche differentiation by increasing the overlap in germination time between small and large seeds. In turn, reduced temporal niche differentiation may increase competition in the process of community assembly. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Chapter 26. Seed germination

Treesearch

Kent R. Jorgensen; G. Richard Wilson

2004-01-01

Seed germination represents the means for survival and spread of many plants (McDonough 1977). Germination consists of three overlapping processes: (1) absorption of water, mainly by imbibition, causing swelling of the seed; (2) concurrent enzymatic activity and increased respiration and assimilation rates; and (3) cell enlargement and divisions resulting in emergence...

iTRAQ Protein Profile Differential Analysis of Dormant and Germinated Grassbur Twin Seeds Reveals that Ribosomal Synthesis and Carbohydrate Metabolism Promote Germination Possibly Through the PI3K Pathway.

PubMed

Zhang, Guo-Liang; Zhu, Yue; Fu, Wei-Dong; Wang, Peng; Zhang, Rui-Hai; Zhang, Yan-Lei; Song, Zhen; Xia, Gui-Xian; Wu, Jia-He

2016-06-01

Grassbur is a destructive and invasive weed in pastures, and its burs can cause gastric damage to animals. The strong adaptability and reproductive potential of grassbur are partly due to a unique germination mechanism whereby twin seeds develop in a single bur: one seed germinates, but the other remains dormant. To investigate the molecular mechanism of seed germination in twin seeds, we used isobaric tags for relative and absolute quantitation (iTRAQ) to perform a dynamic proteomic analysis of germination and dormancy. A total of 1,984 proteins were identified, 161 of which were considered to be differentially accumulated. The differentially accumulated proteins comprised 102 up-regulated and 59 down-regulated proteins. These proteins were grouped into seven functional categories, ribosomal proteins being the predominant group. The authenticity and accuracy of the results were confirmed by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time reverse transcription-PCR (qPCR). A dynamic proteomic analysis revealed that ribosome synthesis and carbohydrate metabolism affect seed germination possibly through the phosphoinositide 3-kinase (PI3K) pathway. As the PI3K pathway is generally activated by insulin, analyses of seeds treated with exogenous insulin by qPCR, ELISA and iTRAQ confirmed that the PI3K pathway can be activated, which suppresses dormancy and promotes germination in twin grassbur seeds. Together, these results show that the PI3K pathway may play roles in stimulating seed germination in grassbur by modulating ribosomal synthesis and carbohydrate metabolism. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Effects of origin, seasons and storage under different temperatures on germination of Senecio vulgaris (Asteraceae) seeds.

PubMed

Ndihokubwayo, Noel; Nguyen, Viet-Thang; Cheng, Dandan

2016-01-01

Invasive plants colonize new environments, become pests and cause biodiversity loss, economic loss and health damage. Senecio vulgaris L. (Common groundsel, Asteraceae), a widely distributing cosmopolitan weed in the temperate area, is reported with large populations in the north-eastern and south-western part, but not in southern, central, or north-western parts of China. We studied the germination behavior of S. vulgaris to explain the distribution and the biological invasion of this species in China. We used seeds originating from six native and six invasive populations to conduct germination experiments in a climate chamber and under outdoor condition. When incubated in a climate chamber (15 °C), seeds from the majority of the populations showed >90% germination percentage (GP) and the GP was equal for seeds with a native and invasive origin. The mean germination time (MGT) was significantly different among the populations. Under outdoor conditions, significant effects of origin, storage conditions (stored at 4 °C or ambient room temperature, ca. 27 °C) and seasons (in summer or autumn) were observed on the GP while the MGT was only affected by the season. In autumn, the GP (38.6%) was higher and the MGT was slightly longer than that in summer. In autumn, seeds stored at 4 °C showed higher GP than those stored at ambient room temperature (ca.27 °C), and seeds from invasive populations revealed higher GP than those from native populations. The results implied that the high temperature in summer has a negative impact on the germination and might cause viability loss or secondary dormancy to S. vulgaris seeds. Our study offers a clue to exploring what factor limits the distribution of S. vulgaris in China by explaining why, in the cities in South-East China and central China such as Wuhan, S. vulgaris cannot establish natural and viable populations.

Seed germination ecology of Echinochloa glabrescens and its implication for management in rice (Oryza sativa L.).

PubMed

Opeña, Jhoana L; Chauhan, Bhagirath S; Baltazar, Aurora M

2014-01-01

Echinochloa glabrescens is a C4 grass weed that is very competitive with rice when left uncontrolled. The competitive ability of weeds is intensified in direct-seeded rice production systems. A better understanding is needed of factors affecting weed seed germination, which can be used as a component of integrated weed management in direct-seeded rice. This study was conducted to determine the effects of temperature, light, salt and osmotic stress, burial depth, crop residue, time and depth of flooding, and herbicide application on the emergence, survival, and growth of two populations [Nueva Ecija (NE) and Los Baños (IR)] of E. glabrescens. Seeds from both populations germinated at all temperatures. The NE population had a higher germination rate (88%) from light stimulation than did the IR population (34%). The salt concentration and osmotic potential required to inhibit 50% of germination were 313 mM and -0.24 MPa, respectively, for the NE population and 254 mM and -0.33 MPa, respectively, for the IR population. Emergence in the NE population was totally inhibited at 4-cm burial depth in the soil, whereas that of the IR population was inhibited at 8 cm. Compared with zero residue, the addition of 5 t ha(-1) of rice residue reduced emergence in the NE and IR populations by 38% and 9%, respectively. Early flooding (within 2 days after sowing) at 2-cm depth reduced shoot growth by 50% compared with non-flooded conditions. Pretilachlor applied at 0.075 kg ai ha(-1) followed by shallow flooding (2-cm depth) reduced seedling emergence by 94-96% compared with the nontreated flooded treatment. Application of postemergence herbicides at 4-leaf stage provided 85-100% control in both populations. Results suggest that integration of different strategies may enable sustainable management of this weed and of weeds with similar germination responses.

Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis.

PubMed

Krawczyk, Antonina O; de Jong, Anne; Omony, Jimmy; Holsappel, Siger; Wells-Bennik, Marjon H J; Kuipers, Oscar P; Eijlander, Robyn T

2017-04-01

spore responsiveness to nutrient germination triggers, among 17 strains of B. subtilis , including 9 isolates from spoiled food products. Spores of industrial foodborne isolates exhibited, on average, less efficient and slower germination responses and required more severe heat activation than spores from other sources. High heat activation requirements and inefficient, slow germination correlated with elevated resistance of spores to heat and with specific genetic features, indicating a common genetic basis of these three phenotypic traits. Clearly, interstrain variation and numerous factors that shape spore germination behavior challenge standardization of methods to recover highly heat-resistant spores from the environment and have an impact on the efficacy of preservation techniques used by the food industry to control spores. Copyright © 2017 American Society for Microbiology.

Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis

PubMed Central

Krawczyk, Antonina O.; de Jong, Anne; Omony, Jimmy; Holsappel, Siger; Wells-Bennik, Marjon H. J.; Eijlander, Robyn T.

2017-01-01

increases spore responsiveness to nutrient germination triggers, among 17 strains of B. subtilis, including 9 isolates from spoiled food products. Spores of industrial foodborne isolates exhibited, on average, less efficient and slower germination responses and required more severe heat activation than spores from other sources. High heat activation requirements and inefficient, slow germination correlated with elevated resistance of spores to heat and with specific genetic features, indicating a common genetic basis of these three phenotypic traits. Clearly, interstrain variation and numerous factors that shape spore germination behavior challenge standardization of methods to recover highly heat-resistant spores from the environment and have an impact on the efficacy of preservation techniques used by the food industry to control spores. PMID:28130296

Macroconidial development and germination in Trichophyton mentagrophytes.

PubMed

Niimi, K; Niimi, M; Harada, K; Tokunaga, M; Tokunaga, J

1988-02-01

Trichophyton Mentagrophytes was investigated for macroconidial development with particular emphasis on the conidial ageing by light and scanning electron microscopy. Macroconidial germination was also studied under various conditions. Sabouraud glucose agar supplemented with 3% NaCl was used to enhance production of macroconidia. After a long-term cultivation macroconidial compartments changed to spherical thick-walled structure. Some 12-month-old macroconidia were still capable of germination. A wide range of temperature (15-37 degrees C), and inoculum of less than 1 X 10(5) conidia per ml of rich media were appropriate for macroconidial germination. The germination process of macroconidia was highly tolerant to NaCl. A small fraction of the conidia were able to germinate even in distilled water without activation. Effect of freeze-thaw or ultraviolet irradiation on macroconidial germination was determined.

Seed germination of Sierra Nevada postfire chaparral species

USGS Publications Warehouse

Keeley, Jon E.; McGinnis, Thomas W.; Bollens, Kim A.

2005-01-01

The California chaparral community has a rich flora of species with different mechanisms for cuing germination to postfire conditions. Here we report further germination experiments that elucidate the response of several widespread shrub species whose germination response was not clear and include other species from the Sierra Nevada, which have not previously been included in germination studies. The shrubs Adenostoma fasciculatum and Eriodictyon crassifolium and the postfire annualMentzelia dispersa exhibited highly significant germination in response to smoke treatments, with some enhanced germination in response to heating as well. The shrubs Fremontodendron californicum and Malacothamnus fremontii were stimulated only by heat-shock treatments. Seeds buried in the soil for one year exhibited substantially higher germination for controls and most treatments. In the case of two postfire annuals, Mimulus bolanderi and M. gracilipes, germination of fresh seed was significantly greater with smoke or heating but after soil storage, over two-thirds of the control seeds germinated and treatment effects were not significant. These two annuals are generally restricted to postfire conditions and it is suggested that control germination of soil-stored seed may be a light-response (which was not tested here) as previously reported for another chaparral species in that genus.

[Study on germination characteristics of Disporum cantoniense].

PubMed

Huang, Nan; Wang, Hua-Lei; Zhao, Zhi; Liu, Hong-Chang; Luo, Chun-Li; Li, Jin-Ling; Luo, Fu-Lai; Huang, Ming-Jin

2012-11-01

To study the seed germination characteristic and optimal germination condition of wild Disporum cantoniense. Used wild Disporum cantoniense seed as the test materials, the rate of water absorption of the seed was determined. The germination rates under different conditions, along a temperature gradient (15, 20, 25 and 30 degres C), in light or dark, on top or between wet filter papers, and keeping or removing the seed coat, were determined respectively using petri dish method. At the same time germination trends were observed. The thousand seed weight was 33.24 g, and the seed water-absorbing reached saturation pot after soaking for 30 h. Higher germination rates were respectively recorded at 25 degrees C, between filter papers, and in dark after 24 h soaking in the pretreatment solution. The optimal condition for the germination of the seed of wild Disporum cantoniense is as follow: keeping testa, seed soaking for 24 h in seed germination agent and being incubated between wet filter papers in dark at 25 degrees C.

Effects of NaCl stress on seed germination and seedling development of Brassica insularis Moris (Brassicaceae).

PubMed

Santo, A; Mattana, E; Frigau, L; Marzo Pastor, A; Picher Morelló, M C; Bacchetta, G

2017-05-01

Brassica insularis is a protected plant that grows on both coastal and inland cliffs in the western Mediterranean Basin. The objective of this study was to test if any variability exists in the salt stress response during seed germination and seedling development in this species relative to its provenance habitat. Variability among three populations in the salt stress effects on seed germination and recovery under different temperatures was evaluated. The effect of nebulisation of a salt solution on seedling development was evaluated between populations growing at different distances from the sea. Seeds of B. insularis could germinate at NaCl concentrations up to 200 mm. Seed viability was negatively affected by salt, and recovery ability decreased with increasing temperature or salinity. Inter-population variability was detected in salt response during the seed germination phase, as well as in seedling salt spray tolerance. The inland population seedlings had drastically decreased survival and life span and failed to survive to the end of the experiment. In contrast, at least 90% of the coastal seedlings survived, even when sprayed at the highest frequency with salt solution. This study allowed investigation of two natural factors, soil salinity and marine aerosols, widely present in the B. insularis habitat, and provided the first insights into ecology of this protected species and its distribution in the Mediterranean. These results might be useful in understanding the actual distributions of other species with the same ecology that experience these same abiotic parameters. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Seed Heteromorphism and Effects of Light and Abiotic Stress on Germination of a Typical Annual Halophyte Salsola ferganica in Cold Desert

PubMed Central

Ma, Yali; Wang, Juan; Zhang, Jinghua; Zhang, Shiyue; Liu, Yanxia; Lan, Haiyan

2018-01-01

Seed heteromorphism is a common characteristic of halophyte and an adaptation to the spatial and temporal variations of natural habitats. Differences in dormancy and germination requirements have been documented in heteromorphic seeds of many species, but the mechanisms for maintenance between different status in various populations have not been well-understood. Salsola ferganica is a typical annual halophyte in Chenopodiaceae distributed in cold desert, in the present study, we found that it could produce three distinct types of seed according to the shape and size of winged perianth (WP), which differed in dispersal ability, dormancy and germination behaviors. Our further investigation revealed that light could significantly promote germination of heteromorphic seeds of S. ferganica, and WP inhibited while GA3 enhanced germination, which suggests that S. ferganica seeds possessed a photo-sensitive combined with morphological and non-deep physiological dormancy type, in which light was the dominant factor. Not like other desert plant species, the germinability of heteromorphic seeds of S. ferganica could not sustain for long (only 1–2 years), especially the small seeds, and was affected by storage time, temperature, salinity, even the environmental conditions of the maternal plant. Thus, the differences of characteristics existed among heteromorphic seeds and variations of heteromorphic ratio among different calendar years were presumed as diverse adaptation strategies integrated in the individual mother plant, and might apply important ecological significance for successful reproduction of the species in the unpredictable cold desert. PMID:29387073

An immunocytochemical study of the germinal layer vasculature in the developing fetal brain using Ulex europaeus 1 lectin.

PubMed

Gould, S J; Howard, S

1988-10-01

The characteristics of the germinal matrix vasculature were studied in the developing fetal brain using immunocytochemical methods. A preliminary comparative immunocytochemical study was made on six fetal brains to compare endothelial staining by Ulex europaeus I lectin with that of antibody to Factor VIII related antigen. Ulex was found to stain germinal layer vessels better than Factor VIII related antigen. Subsequently, the germinal layers of a further 15 fetal and preterm infant brains ranging from 13 to 35 weeks' gestation were stained with Ulex europaeus I to demonstrate the vasculature. With increasing gestation, there was a gradual increase in vessel density, particularly of capillaries. This was not a uniform process. A plexus of capillaries was prominent immediately beneath the ependyma while the more central parts of the germinal matrix contained fewer, but often larger diameter, vessels. The variation in vessel density which was a feature of the later gestation brains may have implications for local blood flow and may be a factor in haemorrhage at this site.

Oxygen dependency of germinating Brassica seeds

NASA Astrophysics Data System (ADS)

Park, Myoung Ryoul; Hasenstein, Karl H.

2016-02-01

Establishing plants in space, Moon or Mars requires adaptation to altered conditions, including reduced pressure and composition of atmospheres. To determine the oxygen requirements for seed germination, we imbibed Brassica rapa seeds under varying oxygen concentrations and profiled the transcription patterns of genes related to early metabolism such as starch degradation, glycolysis, and fermentation. We also analyzed the activity of lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH), and measured starch degradation. Partial oxygen pressure (pO2) greater than 10% resulted in normal germination (i.e., protrusion of radicle about 18 hours after imbibition) but lower pO2 delayed and reduced germination. Imbibition in an oxygen-free atmosphere for three days resulted in no germination but subsequent transfer to air initiated germination in 75% of the seeds and the root growth rate was transiently greater than in roots germinated under ambient pO2. In hypoxic seeds soluble sugars degraded faster but the content of starch after 24 h was higher than at ambient oxygen. Transcription of genes related to starch degradation, α-amylase (AMY) and Sucrose Synthase (SUS), was higher under ambient O2 than under hypoxia. Glycolysis and fermentation pathway-related genes, glucose phosphate isomerase (GPI), 6-phosphofructokinase (PFK), fructose 1,6-bisphosphate aldolase (ALD), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate decarboxylase (PDC), LDH, and ADH, were induced by low pO2. The activity of LDH and ADH was the highest in anoxic seeds. Germination under low O2 conditions initiated ethanolic fermentation. Therefore, sufficient oxygen availability is important for germination before photosynthesis provides necessary oxygen and the determination of an oxygen carrying capacity is important for uniform growth in space conditions.

Effect of Germination and Fermentation on Carbohydrate Composition of Australian Sweet Lupin and Soybean Seeds and Flours.

PubMed

Kaczmarska, Kornelia T; Chandra-Hioe, Maria V; Zabaras, Dimitrios; Frank, Damian; Arcot, Jayashree

2017-11-22

This study investigated the effect of germination and fermentation on the composition of carbohydrates in Australian sweet lupin. Specifically, the amount of sugars (sucrose, fructose, and glucose), starch, oligosaccharides (verbascose, stachyose, and raffinose), and dietary fiber were measured in germinated lupin seeds and fermented lupin flour, and compared with those in soy. High performance liquid chromatography coupled with refractive index was employed for quantitation of sugars, starch, and oligosaccharides, and gas chromatography coupled with a flame ionization detector was used for quantitation of simple sugars in total, and soluble, and insoluble dietary fiber. The enzyme activities of α-amylase and α-glucosidase were compared before and after germination or fermentation. The α-amylase activity in germinated lupin increased to  ∼17 nmol/mL/min/0.1 g and in germinated soy∼32; in fermented lupin, the activity increased to ∼52, while in fermented soy it decreased to ∼20. In general, germination or fermentation decreased the oligosaccharide content, and increased the total sugar in samples (p < 0.05). Total oligosaccharides in lupin after uncontrolled germination were reduced by 98% to 6 mg/g, and after controlled germination reduced by 44% to 86 mg/g. Fermentation with yogurt culture lowered the content of total oligosaccharides due to 94% decrease in stachyose. Total oligosaccharides in soy flour prior to fermentation were 180 mg/g and significantly decreased to ∼124 mg/g in fermented soy. Germination did not affect the starch content. There was no significant change in the amounts of total, soluble, and insoluble dietary fiber after germination or fermentation of lupin except for galactose, which was significantly reduced in germinated lupin seeds. Soluble dietary fiber in germinated soy significantly increased. Germination and fermentation are simple and effective techniques to reduce the oligosaccharides while maintaining the composition of

Reversible Inhibition of Spore Germination by Alcohols 1

PubMed Central

Trujillo, Ralph; Laible, Nancy

1970-01-01

Low levels of alcohols have been found to inhibit the process of spore germination. The extent of germination is dependent upon the concentration of alcohol present in the germinating medium. This inhibition is reversible since removal of the alcohol from the spore environment allows germination to proceed. PMID:4993360

Modeling analysis on germination and seedling growth using ultrasound seed pretreatment in switchgrass.

PubMed

Wang, Quanzhen; Chen, Guo; Yersaiyiti, Hayixia; Liu, Yuan; Cui, Jian; Wu, Chunhui; Zhang, Yunwei; He, Xueqing

2012-01-01

Switchgrass is a perennial C4 plant with great potential as a bioenergy source and, thus, a high demand for establishment from seed. This research investigated the effects of ultrasound treatment on germination and seedling growth in switchgrass. Using an orthogonal matrix design, conditions for the ultrasound pretreatment in switchgrass seed, including sonication time (factor A), sonication temperature (factor B) and ultrasound output power (factor C), were optimized for germinating and stimulating seedling growth (indicated as plumular and radicular lengths) through modeling analysis. The results indicate that sonication temperature (B) was the most effective factor for germination, whereas output power (C) had the largest effect on seedling growth when ultrasound treatment was used. Combined with the analyses of range, variance and models, the final optimal ultrasonic treatment conditions were sonication for 22.5 min at 39.7°C and at an output power of 348 W, which provided the greatest germination percentage and best seedling growth. For this study, the orthogonal matrix design was an efficient method for optimizing the conditions of ultrasound seed treatment on switchgrass. The electrical conductivity of seed leachates in three experimental groups (control, soaked in water only, and ultrasound treatment) was determined to investigate the effects of ultrasound on seeds and eliminate the effect of water in the ultrasound treatments. The results showed that the electrical conductivity of seed leachates during either ultrasound treatment or water bath treatment was significantly higher than that of the control, and that the ultrasound treatment had positive effects on switchgrass seeds.

Lab and Field Warming Similarly Advance Germination Date and Limit Germination Rate for High and Low Elevation Provenances of Two Widespread Subalpine Conifers

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

Kueppers, Lara; Faist, Akasha; Ferrenberg, Scott

Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. Here, we tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 °C warmer, and two soil moisture levels. We also tracked germinationmore » rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by ~300 m elevation. Warming advanced germination timing and initial seedling development by a total of ~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Altogether these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts.« less

Lab and Field Warming Similarly Advance Germination Date and Limit Germination Rate for High and Low Elevation Provenances of Two Widespread Subalpine Conifers

DOE PAGES

Kueppers, Lara; Faist, Akasha; Ferrenberg, Scott; ...

2017-11-11

Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. Here, we tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 °C warmer, and two soil moisture levels. We also tracked germinationmore » rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by ~300 m elevation. Warming advanced germination timing and initial seedling development by a total of ~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Altogether these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts.« less

Germination responses to current and future temperatures of four seeder shrubs across a latitudinal gradient in western Iberia.

PubMed

Chamorro, Daniel; Luna, Belén; Moreno, José M

2017-01-01

Species differ in their temperature germination niche. Populations of a species may similarly differ across the distribution range of the species. Anticipating the impacts of climate variability and change requires understanding the differential sensitivity to germination temperature among and within species. Here we studied the germination responses of four hard-seeded Cistaceae seeders to a range of current and future temperatures. Seeds were collected at sites across the Iberian Peninsula and exposed or not exposed to a heat shock to break dormancy, then set to germinate under four temperature regimes. Temperatures were varied daily and seasonally, simulating the temperature range across the gradient, plus an increased temperature simulating future climate. Time to germination onset and cumulative germination at the end of each season were analyzed for the effects of temperature treatments, seasons, and local climate (temperature of the germination period, T gp ) at each site. T gp was a significant covariate of germination in all species but Cistus populifolius. Temperature treatments significantly affected Cistus ladanifer, C. salviifolius, and Halimium ocymoides. Germination occurred in simulated autumn conditions, with little germination occurring at later seasons, except in unheated seeds of H. ocymoides. Exposure to a heat shock changed the sensitivity to temperature treatments and the relationships with T gp . Germination responses to temperature differ not only among species but also within species across their latitudinal range. The responses were idiosyncratic and related to the local climate of the population. This germination variability complicates generalizing the impacts of climate variability and climate change. © 2017 Botanical Society of America.

Sulfinylated Azadecalins act as functional mimics of a pollen germination stimulant in Arabidopsis pistils

PubMed Central

Qin, Yuan; Wysocki, Ronald J; Somogyi, Arpad; Feinstein, Yelena; Franco, Jessica Y; Tsukamoto, Tatsuya; Dunatunga, Damayanthi; Levy, Clara; Smith, Steven; Simpson, Robert; Gang, David; Johnson, Mark A; Palanivelu, Ravishankar

2011-01-01

SUMMARY Polarized cell elongation is triggered by small molecule cues during development of diverse organisms. During plant reproduction, pollen interactions with the stigma result in the polar outgrowth of a pollen tube, which delivers sperm cells to the female gametophyte to effect double fertilization. In many plants, pistils stimulate pollen germination. However, in Arabidopsis, the effect of pistils on pollen germination and the pistil factors that stimulate pollen germination remain poorly characterized. Here, we demonstrate that stigma, style, and ovules in Arabidopsis pistils stimulate pollen germination. We isolated an Arabidopsis pistil extract fraction that stimulates Arabidopsis pollen germination, and employed ultrahigh resolution ESI FT-ICR and MS/MS techniques to accurately determine the mass (202.126 daltons) of a compound that is specifically present in this pistil extract fraction. Using the molecular formula (C10H19NOS) and tandem mass spectral fragmentation patterns of the m/z (mass to charge ratio) 202.126 ion, we postulated chemical structures, devised protocols, synthesized N-Methanesulfinyl 1- and 2-azadecalins that are close structural mimics of the m/z 202.126 ion, and showed that they are sufficient to stimulate Arabidopsis pollen germination in vitro (30 µM stimulated ~50% germination) and elicit accession-specific response. Although N-Methanesulfinyl 2-azadecalin stimulated pollen germination in three species of Lineage I of Brassicaceae, it did not induce a germination response in Sisymbrium irio (Lineage II of Brassicaceae) and tobacco, indicating that activity of the compound is not random. Our results show that Arabidopsis pistils promote germination by producing azadecalin-like molecules to ensure rapid fertilization by the appropriate pollen. PMID:21801250

Response of soybean seed germination to cadmium and acid rain.

PubMed

Liu, Ting Ting; Wu, Peng; Wang, Li Hong; Zhou, Qing

2011-12-01

Cadmium (Cd) pollution and acid rain are the main environmental issues, and they often occur in the same agricultural region. Nevertheless, up to now, little information on the combined pollution of Cd(2+) and acid rain action on crops were presented. Here, we investigated the combined effect of Cd(2+) and acid rain on the seed germination of soybean. The results indicated that the single treatment with the low level of Cd(2+) (0.18, 1.0, 3.0 mg L(-1)) or acid rain (pH ≥3.0) could not affect the seed germination of soybean, which was resulted in the increased activities of peroxidase and catalase. The single treatment with the high concentration of Cd(2+) (>6 mg L(-1)) or acid rain at pH 2.5 decreased the activities of peroxidase and catalase, damaged the cell membrane and then decreased the seed germination of soybean. Meanwhile, the same toxic effect was observed in the combined treatment with Cd(2+) and acid rain, and the combined treatment had more toxic effect than the single treatment with Cd(2+) or acid rain. Thus, the combined pollution of Cd(2+) and acid rain had more potential threat to the seed germination of soybean than the single pollution of Cd(2+) or acid rain.

Phytotoxicity of glyphosate in the germination of Pisum sativum and its effect on germinated seedlings

PubMed Central

2017-01-01

The present study evaluated the effects of glyphosate on Pisum sativum germination as well as its effect on the physiology and biochemistry of germinated seedlings. Different physico-chemical biomarkers, viz., chlorophyll, root and shoot length, total protein and soluble sugar, along with sodium and potassium concentration, were investigated in germinated seedlings at different glyphosate concentrations. This study reports the influence of different concentrations of glyphosate on pea seeds and seedlings. Physicochemical biomarkers were significantly changed by glyphosate exposure after 15 days. The germination of seedlings under control conditions (0 mg/L) was 100% after 3 days of treatment but at 3 and 4 mg/L glyphosate, germination was reduced to 55 and 40%, respectively. Physiological parameters like root and shoot length decreased monotonically with increasing glyphosate concentration, at 14 days of observation. Average root and shoot length (n=30 in three replicates) were reduced to 14.7 and 17.6%, respectively, at 4 mg/L glyphosate. Leaf chlorophyll content also decreased, with a similar trend to root and shoot length, but the protein content initially decreased and then increased with an increase in glyphosate concentration to 3 mg/L. The study suggests that glyphosate reduces the soluble sugar content significantly, by 21.6% (v/v). But internal sodium and potassium tissue concentrations were significantly altered by glyphosate exposure with increasing concentrations of glyphosate. Biochemical and physiological analysis also supports the inhibitory effect of glyphosate on seed germination and biochemical effects on seedlings. PMID:28728354

Factors influencing the scarification and germination of three montane Sierra Nevada shrubs

Treesearch

J. Boone Kaufmann; R. E. Martin

1991-01-01

Following fires in the forested ecosystems of the northern Sierra Nevada, California, early successional communities are often dominated by shrubs that arise from seeds that have remained viable in soil seedbanks for long periods. The germination response of seeds of three seral montane shrub species was investigated following exposure to differing types of heat (wet...

Cerium enhances germination and shoot growth, and alters mineral nutrient concentration in rice

PubMed Central

García-Morales, Soledad; Pérez-Sato, Juan Antonio

2018-01-01

Cerium (Ce) belongs to the rare earth elements (REEs), and although it is not essential for plants, it can stimulate growth and other physiological processes. The objective of this research was to evaluate the effect of Ce on seed germination, initial seedling growth, and vegetative growth in rice (Oryza sativa L.) cv. Morelos A-98. During the germination process, the seeds were treated with Ce concentrations of 0, 4, 8, and 12 μM; after 5 d, germination percentage was recorded and after 10 d seedling growth was measured. For vegetative growth, a hydroponic system was established where 14-d-old plants without previous Ce treatment were transferred into nutrient solution. After two weeks of acclimatizing, 0, 25, 50, and 100 μM Ce were added to the nutrient solution for 28 d. Ce significantly increased germination and the initial growth variables of the seedlings. During vegetative growth, Ce increased plant height, number of tillers, root volume, and shoot fresh and dry biomass, without affecting root biomass weight. With low Ce concentrations (25 and 50 μM), the concentrations of chlorophylls and amino acids in the shoots were similar to those in the control, like amino acid concentration in the roots at a concentration of 25 μM Ce. Conversely, the concentration of total sugars increased in the shoot with the application of 25, 50, and 100 μM Ce, and in the roots with the application of 50 μM Ce. Also, Ce did not affect the concentration of macro or micronutrients in the shoots. However, in the roots, the high Ce concentration decreased the concentrations of Ca, Fe, Mn, and Zn, while the Mg concentration increased. Our results indicate that Ce, at the right concentrations, can function as a biostimulant in rice germination and growth. PMID:29579100

Modulation of CycD3;1-CDK complexes by phytohormones and sucrose during maize germination.

PubMed

Garza-Aguilar, Sara M; Lara-Núñez, Aurora; García-Ramírez, Elpidio; Vázquez-Ramos, Jorge M

2017-05-01

Maize CycD3;1 associates to CDKA or CDKB1;1 proteins during germination and the complexes formed develop kinase activity. These complexes appear to vary in size as germination proceeds, suggesting association to different sets of proteins. CycD3;1 and associated CDK proteins respond to phytohormones and sucrose. Results revealed a reduction in the CycD3;1 protein amount along germination in the presence of indoleacetic acid (IAA) or abscisic acid (ABA), although in the latter protein levels recover at the end of germination. While the levels of CDKA increase with IAA, they decrease with ABA. Both phytohormones, IAA and ABA, increase levels of CDKB1;1 only during the early germination times. CycD3;1 associated kinase activity is only reduced by both phytohormones towards the end of the germination period. On the other hand, lack of sucrose in the imbibition medium strongly reduces CycD3;1 protein levels without affecting the levels of neither CDKA nor CDKB1;1. The corresponding CycD3;1 associated kinase activity is also severely decreased. The presence of sucrose in the medium appears to stabilize the CycD3;1 protein levels. © 2016 Scandinavian Plant Physiology Society.

Frugivory and the effects of ingestion by bats on the seed germination of three pioneering plants

NASA Astrophysics Data System (ADS)

de Carvalho-Ricardo, Maria C.; Uieda, Wilson; Fonseca, Renata Cristina B.; Rossi, Marcelo N.

2014-02-01

The dispersion and seedling establishment of pioneering plants can be favoured by the presence of frugivorous bats because the bats usually improve seed germination after ingestion. Although seed germinability is known to vary greatly after ingestion by different bats, the relative contribution of each bat species to seed germination within plant communities is poorly understood. In this study, we first determined the fauna of frugivorous bats in a semideciduous seasonal forest remnant in southern Brazil and subsequently identified the plant species of the seeds passed through their guts. Second, the germination performance (i.e., germination percentage and speed) of the seeds of three pioneering plants (Piper aduncum, Piper hispidinervum and Solanum granuloso-leprosum) ingested by the most abundant bats was compared with that of the non-ingested seeds (seeds collected from fruits). Additionally, the effects on seed germination of different bat species were compared. During one year, five species of frugivorous bats were caught, and the seeds of eleven identifiable plant species (not counting those of undetermined species) were found in their faeces. We found that the germination performance of the seeds of Piper species was significantly enhanced after ingestion by bats, whereas S. granuloso-leprosum seeds had neutral or reduced germinability when seeds in faeces were compared with pulp-removed seeds. Our results revealed that the bat species that were captured exerted different effects upon seed germination; such a disparity is expected to result in different rates of early establishment of these pioneer plants in tropical forests, most likely affecting forest composition and structure, particularly during the initial stages of succession.

Methods for assessing Phytophthora ramorum chlamydospore germination

Treesearch

Joyce Eberhart; Elilzabeth Stamm; Jennifer Parke

2013-01-01

Germination of chlamydospores is difficult to accurately assess when chlamydospores are attached to remnants of supporting hyphae. We developed two approaches for closely observing and rigorously quantifying the frequency of chlamydospore germination in vitro. The plate marking and scanning method was useful for quantifying germination of large...

Arabidopsis DREB2C modulates ABA biosynthesis during germination.

PubMed

Je, Jihyun; Chen, Huan; Song, Chieun; Lim, Chae Oh

2014-09-12

Plant dehydration-responsive element binding factors (DREBs) are transcriptional regulators of the APETELA2/Ethylene Responsive element-binding Factor (AP2/ERF) family that control expression of abiotic stress-related genes. We show here that under conditions of mild heat stress, constitutive overexpression seeds of transgenic DREB2C overexpression Arabidopsis exhibit delayed germination and increased abscisic acid (ABA) content compared to untransformed wild-type (WT). Treatment with fluridone, an inhibitor of the ABA biosynthesis abrogated these effects. Expression of an ABA biosynthesis-related gene, 9-cis-epoxycarotenoid dioxygenase 9 (NCED9) was up-regulated in the DREB2C overexpression lines compared to WT. DREB2C was able to trans-activate expression of NCED9 in Arabidopsis leaf protoplasts in vitro. Direct and specific binding of DREB2C to a complete DRE on the NCED9 promoter was observed in electrophoretic mobility shift assays. Exogenous ABA treatment induced DREB2C expression in germinating seeds of WT. Vegetative growth of transgenic DREB2C overexpression lines was more strongly inhibited by exogenous ABA compared to WT. These results suggest that DREB2C is a stress- and ABA-inducible gene that acts as a positive regulator of ABA biosynthesis in germinating seeds through activating NCED9 expression. Copyright © 2014 Elsevier Inc. All rights reserved.

Overview on the mechanisms of coffee germination and fermentation and their significance for coffee and coffee beverage quality.

PubMed

Waters, Deborah M; Arendt, Elke K; Moroni, Alice V

2017-01-22

Quality of coffee is a complex trait and is influenced by physical and sensory parameters. A complex succession of transformations during the processing of seeds to roasted coffee will inevitably influence the in-cup attributes of coffee. Germination and fermentation of the beans are two bioprocesses that take place during post-harvest treatment, and may lead to significant modifications of coffee attributes. The aim of this review is to address the current knowledge of dynamics of these two processes and their significance for bean modifications and coffee quality. The first part of this review gives an overview of coffee germination and its influence on coffee chemistry and quality. The germination process initiates while these non-orthodox seeds are still inside the cherry. This process is asynchronous and the evolution of germination depends on how the beans are processed. A range of metabolic reactions takes place during germination and can influence the carbohydrate, protein, and lipid composition of the beans. The second part of this review focuses on the microbiota associated with the beans during post-harvesting, exploring its effects on coffee quality and safety. The microbiota associated with the coffee cherries and beans comprise several bacterial, yeast, and fungal species and affects the processing from cherries to coffee beans. Indigenous bacteria and yeasts play a role in the degradation of pulp/mucilage, and their metabolism can affect the sensory attributes of coffee. On the other hand, the fungal population occurring during post-harvest and storage negatively affects coffee quality, especially regarding spoilage, off-tastes, and mycotoxin production.

Variability of germination in digger pine in California

Treesearch

James R. Griffin

1971-01-01

Seeds collected from 17 Pinus sabiniana Dougl. populations in California were tested for germination. Unstratified seeds germinated slower than stratified seeds. Germination of stratified seeds showed distinct population differences. Some populations started germination at 5°C. and reached a level of 60 to 70 percent after 30 days at 25°. Less than...

Factors affecting sign retroreflectivity

DOT National Transportation Integrated Search

2001-01-01

This study was undertaken to better understand the factors that may affect road sign retroreflectivity, specifically age and physical orientation. A better understanding of these factors could provide guidance to ODOT in managing its inventory of roa...

Germination Conditions For Poison Ivy

Treesearch

Nathan M. Schiff; Kristina F. Connor; Margaret S. Devall

2004-01-01

Several scarification and stratification treatments were tested to optimize germination conditions for poison ivy [Toxicodendron radicans (L.) Kunst]. Fall-collected seeds soaked for 1 hour in water showed increasing germination with increasing stratification. Scarification with concentrated sulphuric acid for 30 minutes resulted in approximately 65...

Germination and elongation of flax in microgravity

NASA Astrophysics Data System (ADS)

Levine, Howard G.; Anderson, Ken; Boody, April; Cox, Dave; Kuznetsov, Oleg A.; Hasenstein, Karl H.

2003-05-01

This experiment was conducted as part of a risk mitigation payload aboard the Space Shuttle Atlantis on STS-101. The objectives were to test a newly developed water delivery system, and to determine the optimal combination of water volume and substrate for the imbibition and germination of flax ( Linum usitatissimum) seeds in space. Two different combinations of germination paper were tested for their ability to absorb, distribute, and retain water in microgravity. A single layer of thick germination paper was compared with one layer of thin germination paper under a layer of thick paper. Paper strips were cut to fit snugly into seed cassettes, and seeds were glued to them with the micropyle ends pointing outward. Water was delivered in small increments that traveled through the paper via capillary action. Three water delivery volumes were tested, with the largest (480 μL) outperforming the 400 μL, and 320 μL volumes for percent germination (90.6%) and root growth (mean = 4.1 mm) during the 34-hour spaceflight experiment. The ground control experiment yielded similar results, but with lower rates of germination (84.4%) and shorter root lengths (mean = 2.8 mm). It is not clear if the roots emerged more quickly in microgravity and/or grew faster than the ground controls. The single layer of thick germination paper generally exhibited better overall growth than the two layered option. Significant seed position effects were observed in both the flight and ground control experiments. Overall, the design of the water delivery system, seed cassettes and the germination paper strip concept was validated as an effective method for promoting seed germination and root growth under microgravity conditions.

Influence of the Testa on Seed Dormancy, Germination, and Longevity in Arabidopsis1

PubMed Central

Debeaujon, Isabelle; Léon-Kloosterziel, Karen M.; Koornneef, Maarten

2000-01-01

The testa of higher plant seeds protects the embryo against adverse environmental conditions. Its role is assumed mainly by controlling germination through dormancy imposition and by limiting the detrimental activity of physical and biological agents during seed storage. To analyze the function of the testa in the model plant Arabidopsis, we compared mutants affected in testa pigmentation and/or structure for dormancy, germination, and storability. The seeds of most mutants exhibited reduced dormancy. Moreover, unlike wild-type testas, mutant testas were permeable to tetrazolium salts. These altered dormancy and tetrazolium uptake properties were related to defects in the pigmentation of the endothelium and its neighboring crushed parenchymatic layers, as determined by vanillin staining and microscopic observations. Structural aberrations such as missing layers or a modified epidermal layer in specific mutants also affected dormancy levels and permeability to tetrazolium. Both structural and pigmentation mutants deteriorated faster than the wild types during natural aging at room temperature, with structural mutants being the most strongly affected. PMID:10677433

Involvement of reactive oxygen species in endosperm cap weakening and embryo elongation growth during lettuce seed germination

PubMed Central

Zhang, Yu; Chen, Bingxian; Xu, Zhenjiang; Shi, Zhaowan; Chen, Shanli; Huang, Xi; Chen, Jianxun; Wang, Xiaofeng

2014-01-01

Endosperm cap (CAP) weakening and embryo elongation growth are prerequisites for the completion of lettuce seed germination. Although it has been proposed that the cell wall loosening underlying these processes results from an enzymatic mechanism, it is still unclear which enzymes are involved. Here it is shown that reactive oxygen species (ROS), which are non-enzymatic factors, may be involved in the two processes. In Guasihong lettuce seeds imbibed in water, O2·– and H2O2 accumulated and peroxidase activity increased in the CAP, whereas its puncture force decreased. In addition, in the radicle, the increase in embryo growth potential was accompanied by accumulation of O2·– and an increase in peroxidase activity. Imbibing seeds in 0.3% sodium dichloroisocyanurate (SDIC) reduced endosperm viability and the levels of O2·–, H2O2, and peroxidase activity in the CAP, whereas the decrease in its puncture force was inhibited. However, in the embryo, SDIC did not affect the accumulation of O2·–, peroxidase activity, and the embryo growth potential. As a result, SDIC caused atypical germination, in which the endosperm ruptured at the boundary between the CAP and lateral endosperm. ROS scavengers and ROS generation inhibitors inhibited the CAP weakening and also decreased the embryo growth potential, thus decreasing the percentage of seed germination. Exogenous ROS and ROS generation inducers increased the percentage of CAP rupture to some extent, and the addition of H2O2 to 0.3% SDIC enabled some seeds to undergo typical germination. PMID:24744430

Germination and growth of native and invasive plants on soil associated with biological control of tamarisk (Tamarix spp.)

USGS Publications Warehouse

Sherry, Rebecca A.; Shafroth, Patrick B.; Belnap, Jayne; Ostoja, Steven M.; Reed, Sasha C.

2016-01-01

Introductions of biocontrol beetles (tamarisk beetles) are causing dieback of exotic tamarisk in riparian zones across the western United States, yet factors that determine plant communities that follow tamarisk dieback are poorly understood. Tamarisk-dominated soils are generally higher in nutrients, organic matter, and salts than nearby soils, and these soil attributes might influence the trajectory of community change. To assess physical and chemical drivers of plant colonization after beetle-induced tamarisk dieback, we conducted separate germination and growth experiments using soil and litter collected beneath defoliated tamarisk trees. Focal species were two common native (red threeawn, sand dropseed) and two common invasive exotic plants (Russian knapweed, downy brome), planted alone and in combination. Nutrient, salinity, wood chip, and litter manipulations examined how tamarisk litter affects the growth of other species in a context of riparian zone management. Tamarisk litter, tamarisk litter leachate, and fertilization with inorganic nutrients increased growth in all species, but the effect was larger on the exotic plants. Salinity of 4 dS m−1 benefitted Russian knapweed, which also showed the largest positive responses to added nutrients. Litter and wood chips generally delayed and decreased germination; however, a thinner layer of wood chips increased growth slightly. Time to germination was lengthened by most treatments for natives, was not affected in exotic Russian knapweed, and was sometimes decreased in downy brome. Because natives showed only small positive responses to litter and fertilization and large negative responses to competition, Russian knapweed and downy brome are likely to perform better than these two native species following tamarisk dieback.

Identification of HDA15-PIF1 as a key repression module directing the transcriptional network of seed germination in the dark

PubMed Central

Gu, Dachuan; Chen, Chia-Yang; Zhao, Minglei; Zhao, Linmao; Duan, Xuewu

2017-01-01

Abstract Light is a major external factor in regulating seed germination. Photoreceptor phytochrome B (PHYB) plays a predominant role in promoting seed germination in the initial phase after imbibition, partially by repressing phytochrome-interacting factor1 (PIF1). However, the mechanism underlying the PHYB-PIF1-mediated transcription regulation remains largely unclear. Here, we identified that histone deacetylase15 (HDA15) is a negative component of PHYB-dependent seed germination. Overexpression of HDA15 in Arabidopsis inhibits PHYB-dependent seed germination, whereas loss of function of HDA15 increases PHYB-dependent seed germination. Genetic evidence indicated that HDA15 acts downstream of PHYB and represses seed germination dependent on PIF1. Furthermore, HDA15 interacts with PIF1 both in vitro and in vivo. Genome-wide transcriptome analysis revealed that HDA15 and PIF1 co-regulate the transcription of the light-responsive genes involved in multiple hormonal signaling pathways and cellular processes in germinating seeds in the dark. In addition, PIF1 recruits HDA15 to the promoter regions of target genes and represses their expression by decreasing the histone H3 acetylation levels in the dark. Taken together, our analysis uncovered the role of histone deacetylation in the light-regulated seed germination process and identified that HDA15-PIF1 acts as a key repression module directing the transcription network of seed germination. PMID:28444370

Germination and elongation of flax in microgravity

NASA Astrophysics Data System (ADS)

Levine, H.; Anderson, K.; Boody, A.; Cox, D.; Kuznetsov, O.; Hasenstein, K.

This experiment was conducted as part of a risk mitigation BIOTUBE Precursor hardware demonstration payload aboard the Space Shuttle Atlantis on STS-101. The objectives were to provide a demonstration and test of the newly developed BIOTUBE water delivery subsystem, and to determine the optimal water volume and germination paper combination for the automated imbibition and germination of flax (Linum usitatissimum) seeds in space. Two different substrate treatments of standard laboratory germination paper were tested for their ability to absorb, distribute, and retain water in microgravity. The first consisted of one layer of thick germination paper (designated "heavy"), and the second consisted of one layer of standard germination paper (designated "normal") under one layer of heavy germination paper. The germination paper strips were cut (4 X 1.6 cm) to fit snugly into seed cassettes. The seeds were attached to them by applying guar glue (1.25% w/v) drops to 8 premarked spots and the seeds orientated with the micropyle ends pointing outward. Water was delivered in 50 μL boluses which slowly traveled down the paper via capillary action (eliminating the complications caused by excess water pooling around the seed's surface). The data indicated that the 480 μL water delivery volume provided the best wetness level treatment for both percent germination (90.6%) and overall root growth (mean = 4.1 mm) during the 34 hour spaceflight experiment. The ground control experiment experienced similar results, but with slightly lower rates of germination (84.4%) and significantly shorter root lengths (2.8 mm). It is not clear if the roots emerged more quickly in microgravity and/or grew faster than the ground controls. The single layer of "Heavy" germination paper generally exhibited better overall growth than the two layered option. This in conjunction with the simplicity of using a single strip per seed cassette argues in favor of its selection. Significant seed position

The effect of altitude on breaking seed dormancy and stimulation of seed germination of Persian hogweed (Heracleum persicum).

PubMed

Salehani, M Khajavi; Mahmoudi, J; Mahdavi, S Kh; Habibzadeh, R

2013-01-01

Persian hogweed is a perennial herb and aromatic plant which has pharmaceutical and fodder values, and the main propagation method of this species is seed. The goal of this study was to investigate the effect of altitude on breaking dormancy and stimulate seed germination of this species. The study was designed and carried out using the test of seed analysis. For our purpose, seeds were collected from three different altitudes (1700, 2200, 2700 masl) in Kojoor area. After initial purification, germination percent (GP) and speed (GS) of each elevation were determined by cold stratification compared to control. According to results, control seeds did not germinate, showing that the seeds of this species need to be treated. Statistical analysis of results showed that there are significant differences between GP and GS of each elevation, as seeds of higher elevation had slower and less germination in longer periods. So, changes in elevation are an effective factor on seed germination characteristics of this species and this factor has to be considered in seed preparation and restoration with this species.

Increasing the antioxidant activity, total phenolic and flavonoid contents by optimizing the germination conditions of amaranth seeds.

PubMed

Perales-Sánchez, Janitzio X K; Reyes-Moreno, Cuauhtémoc; Gómez-Favela, Mario A; Milán-Carrillo, Jorge; Cuevas-Rodríguez, Edith O; Valdez-Ortiz, Angel; Gutiérrez-Dorado, Roberto

2014-09-01

The aim of this study was to optimize the germination conditions of amaranth seeds that would maximize the antioxidant activity (AoxA), total phenolic (TPC), and flavonoid (TFC) contents. To optimize the germination bioprocess, response surface methodology was applied over three response variables (AoxA, TPC, TFC). A central composite rotable experimental design with two factors [germination temperature (GT), 20-45 ºC; germination time (Gt), 14-120 h] in five levels was used; 13 treatments were generated. The amaranth seeds were soaked in distilled water (25 °C/6 h) before germination. The sprouts from each treatment were dried (50 °C/8 h), cooled, and ground to obtain germinated amaranth flours (GAF). The best combination of germination bioprocess variables for producing optimized GAF with the highest AoxA [21.56 mmol trolox equivalent (TE)/100 g sample, dw], TPC [247.63 mg gallic acid equivalent (GAE)/100 g sample, dw], and TFC [81.39 mg catechin equivalent (CAE)/100 g sample, dw] was GT = 30 ºC/Gt = 78 h. The germination bioprocess increased AoxA, TPC, and TFC in 300-470, 829, and 213%, respectively. The germination is an effective strategy to increase the TPC and TFC of amaranth seeds for enhancing functionality with improved antioxidant activity.

Effects of the decomposing liquid of Cladophora oligoclona on Hydrilla verticillata turion germination and seedling growth.

PubMed

Zhang, Lu; Peng, Xue; Liu, Biyun; Zhang, Yi; Zhou, Qiaohong; Wu, Zhenbin

2018-08-15

Excessive proliferation of filamentous green algae (FGA) has been considered an important factor resulting in the poor growth or even decline of submerged macrophytes. However, there is a lack of detailed information regarding the effect of decaying FGA on submerged macrophytes. This study aimed to investigate whether the decomposing liquid from Cladophora oligoclona negatively affects Hydrilla verticillata turion germination and seedling growth. The results showed that the highest concentrations of decomposing liquid treatments inhibited the turion germination rate, which was the lowest than other treatments, at only 84%. The chlorophyll a fluorescence (JIP test) and physiological indicators (chlorophyll a content, soluble sugars, Ca 2+ /Mg 2+ -ATPase and PAL activity) were also measured. The chlorophyll a content in the highest concentration (40% of original decomposing liquid) treatment group decreased by 43.53% than that of the control; however, soluble sugars, Ca 2+ /Mg 2+ -ATPase, and PAL activity increased by 172.46%, 271.19%, and 26.43% respectively. The overall results indicated that FGA decay has a considerable effect on submerged macrophyte turion germination and seedling growth, which could inhibit their expansion and reproduction. This study emphasized the need to focus on effects of FGA decomposition on the early growth stages of submerged macrophytes and offered technological guidance for submerged vegetation restoration in lakes and shallow waters. Copyright © 2018 Elsevier Inc. All rights reserved.

Mitochondrial Proteome Studies in Seeds during Germination

PubMed Central

Czarna, Malgorzata; Kolodziejczak, Marta; Janska, Hanna

2016-01-01

Seed germination is considered to be one of the most critical phases in the plant life cycle, establishing the next generation of a plant species. It is an energy-demanding process that requires functioning mitochondria. One of the earliest events of seed germination is progressive development of structurally simple and metabolically quiescent promitochondria into fully active and cristae-containing mitochondria, known as mitochondrial biogenesis. This is a complex and tightly regulated process, which is accompanied by sequential and dynamic gene expression, protein synthesis, and post-translational modifications. The aim of this review is to give a comprehensive summary of seed mitochondrial proteome studies during germination of various plant model organisms. We describe different gel-based and gel-free proteomic approaches used to characterize mitochondrial proteomes of germinating seeds as well as challenges and limitations of these proteomic studies. Furthermore, the dynamic changes in the abundance of the mitochondrial proteomes of germinating seeds are illustrated, highlighting numerous mitochondrial proteins involved in respiration, tricarboxycylic acid (TCA) cycle, metabolism, import, and stress response as potentially important for seed germination. We then review seed mitochondrial protein carbonylation, phosphorylation, and S-nitrosylation as well as discuss the possible link between these post-translational modifications (PTMs) and the regulation of seed germination. PMID:28248229

The rice GERMINATION DEFECTIVE 1, encoding a B3 domain transcriptional repressor, regulates seed germination and seedling development by integrating GA and carbohydrate metabolism

PubMed Central

Guo, Xiaoli; Hou, Xiaomei; Fang, Jun; Wei, Piwei; Xu, Bo; Chen, Mingluan; Feng, Yuqi; Chu, Chengcai

2013-01-01

It has been shown that seed development is regulated by a network of transcription factors in Arabidopsis including LEC1 (LEAFY COTYLEDON1), L1L (LEC1-like) and the B3 domain factors LEC2, FUS3 (FUSCA3) and ABI3 (ABA-INSENSITIVE3); however, molecular and genetic regulation of seed development in cereals is poorly understood. To understand seed development and seed germination in cereals, a large-scale screen was performed using our T–DNA mutant population, and a mutant germination-defective1 (gd1) was identified. In addition to the severe germination defect, the gd1 mutant also shows a dwarf phenotype and abnormal flower development. Molecular and biochemical analyses revealed that GD1 encodes a B3 domain-containing transcription factor with repression activity. Consistent with the dwarf phenotype of gd1, expression of the gibberelic acid (GA) inactivation gene OsGA2ox3 is increased dramatically, accompanied by reduced expression of GA biosynthetic genes including OsGA20ox1, OsGA20ox2 and OsGA3ox2 in gd1, resulting in a decreased endogenous GA4 level. Exogenous application of GA not only induced GD1 expression, but also partially rescued the dwarf phenotype of gd1. Furthermore, GD1 binds to the promoter of OsLFL1, a LEC2/FUS3-like gene of rice, via an RY element, leading to significant up-regulation of OsLFL1 and a large subset of seed maturation genes in the gd1 mutant. Plants over-expressing OsLFL1 partly mimic the gd1 mutant. In addition, expression of GD1 was induced under sugar treatment, and the contents of starch and soluble sugar are altered in the gd1 mutant. These data indicate that GD1 participates directly or indirectly in regulating GA and carbohydrate homeostasis, and further regulates rice seed germination and seedling development. PMID:23581288

Roles of germination-specific lytic enzymes CwlJ and SleB in Bacillus anthracis.

PubMed

Heffron, Jared D; Orsburn, Benjamin; Popham, David L

2009-04-01

The structural characteristics of a spore enable it to withstand stresses that typically kill a vegetative cell. Spores remain dormant until small molecule signals induce them to germinate into vegetative bacilli. Germination requires degradation of the thick cortical peptidoglycan by germination-specific lytic enzymes (GSLEs). Bacillus anthracis has four putative GSLEs, based upon sequence similarities with enzymes in other species: SleB, CwlJ1, CwlJ2, and SleL. In this study, the roles of SleB, CwlJ1, and CwlJ2 were examined. The expression levels of all three genes peak 3.5 h into sporulation. Genetic analysis revealed that, similar to other known GSLEs, none of these gene products are individually required for growth, sporulation, or triggering of germination. However, later germination events are affected in spores lacking CwlJ1 or SleB. Compared to the wild type, germinating spores without CwlJ1 suffer a delay in optical density loss and cortex peptidoglycan release. The absence of SleB also causes a delay in cortex fragment release. A double mutant lacking both SleB and CwlJ1 is completely blocked in cortex hydrolysis and progresses through outgrowth to produce colonies at a frequency 1,000-fold lower than that of the wild-type strain. A null mutation eliminating CwlJ2 has no effect on germination. High-performance liquid chromatography and mass spectroscopy analysis revealed that SleB is required for lytic transglycosylase activity. CwlJ1 also clearly participates in cortex hydrolysis, but its specific mode of action remains unclear. Understanding the lytic germination activities that naturally diminish spore resistance can lead to methods for prematurely inducing them, thus simplifying the process of treating contaminated sites.

Soil salinity: Germination tolerance of alternative oilseed crops for soil health

USDA-ARS?s Scientific Manuscript database

World-wide, saline soils contribute to over US$27.3 billion in agricultural losses annually by reducing plant growth through osmotic imbalances and ion toxicity. Nearly 800,000 ha of salt affected land is located in the northern Great Plains. Limited information is available on the germination of al...

Germination and elongation of flax in microgravity

NASA Technical Reports Server (NTRS)

Levine, Howard G.; Anderson, Ken; Boody, April; Cox, Dave; Kuznetsov, Oleg A.; Hasenstein, Karl H.

2003-01-01

This experiment was conducted as part of a risk mitigation payload aboard the Space Shuttle Atlantis on STS-101. The objectives were to test a newly developed water delivery system, and to determine the optimal combination of water volume and substrate for the imbibition and germination of flax (Linum usitatissimum) seeds in space. Two different combinations of germination paper were tested for their ability to absorb, distribute, and retain water in microgravity. A single layer of thick germination paper was compared with one layer of thin germination paper under a layer of thick paper. Paper strips were cut to fit snugly into seed cassettes, and seeds were glued to them with the micropyle ends pointing outward. Water was delivered in small increments that traveled through the paper via capillary action. Three water delivery volumes were tested, with the largest (480 microliters) outperforming the 400 microliters and 320 microliters volumes for percent germination (90.6%) and root growth (mean=4.1 mm) during the 34-hour spaceflight experiment. The ground control experiment yielded similar results, but with lower rates of germination (84.4%) and shorter root lengths (mean=2.8 mm). It is not clear if the roots emerged more quickly in microgravity and/or grew faster than the ground controls. The single layer of thick germination paper generally exhibited better overall growth than the two layered option. Significant seed position effects were observed in both the flight and ground control experiments. Overall, the design of the water delivery system, seed cassettes and the germination paper strip concept was validated as an effective method for promoting seed germination and root growth under microgravity conditions. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Morpho-colorimetric analysis and seed germination of Brassica insularis Moris (Brassicaceae) populations.

PubMed

Santo, A; Mattana, E; Grillo, O; Bacchetta, G

2015-03-01

Brassica insularis is a perennial plant growing on both coastal and inland cliffs. Three seed lots from Sardinia were analysed using an image analysis system to detect differences in seed morphology, both within and among populations. Germination requirements at constant (5-25 °C) and alternating temperatures (25/10 °C), both in light and in darkness, were evaluated for all populations. In addition, the effect of a dry after-ripening period (90 days at 25 °C) was also investigated. Morpho-colorimetric analysis clearly identified seeds from different populations and discriminated three chromatic categories for seeds belonging to the Isola dei Cavoli coastal population, but not for the inland Masùa and the coastal Planu Sartu. Inter-population variability was also observed in germination behaviour. B. insularis seeds germinated, with percentages up to 60%, in a wide range of temperatures (5-25 °C), and neither light nor dry after-ripening affected final germination percentages. Moisture content measurements were made for seeds of each colour, but there were no particular differences among colours. Inter-populational variability in germination behaviour may be a survival strategy for species growing under unpredictable environmental conditions, such as under Mediterranean climate, while heteromorphy may be due to independent evolutionary divergence processes of the Isola dei Cavoli population. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Differential Activity of Striga hermonthica Seed Germination Stimulants and Gigaspora rosea Hyphal Branching Factors in Rice and Their Contribution to Underground Communication

PubMed Central

Cardoso, Catarina; Charnikhova, Tatsiana; Jamil, Muhammad; Delaux, Pierre-Marc; Verstappen, Francel; Amini, Maryam; Lauressergues, Dominique; Ruyter-Spira, Carolien; Bouwmeester, Harro

2014-01-01

Strigolactones (SLs) trigger germination of parasitic plant seeds and hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi. There is extensive structural variation in SLs and plants usually produce blends of different SLs. The structural variation among natural SLs has been shown to impact their biological activity as hyphal branching and parasitic plant seed germination stimulants. In this study, rice root exudates were fractioned by HPLC. The resulting fractions were analyzed by MRM-LC-MS to investigate the presence of SLs and tested using bioassays to assess their Striga hermonthica seed germination and Gigaspora rosea hyphal branching stimulatory activities. A substantial number of active fractions were revealed often with very different effect on seed germination and hyphal branching. Fractions containing (−)−orobanchol and ent-2'-epi-5-deoxystrigol contributed little to the induction of S. hermonthica seed germination but strongly stimulated AM fungal hyphal branching. Three SLs in one fraction, putative methoxy-5-deoxystrigol isomers, had moderate seed germination and hyphal branching inducing activity. Two fractions contained strong germination stimulants but displayed only modest hyphal branching activity. We provide evidence that these stimulants are likely SLs although no SL-representative masses could be detected using MRM-LC-MS. Our results show that seed germination and hyphal branching are induced to very different extents by the various SLs (or other stimulants) present in rice root exudates. We propose that the development of rice varieties with different SL composition is a promising strategy to reduce parasitic plant infestation while maintaining symbiosis with AM fungi. PMID:25126953

Influence of Environmental Factors, Cultural Practices, and Herbicide Application on Seed Germination and Emergence Ecology of Ischaemum rugosum Salisb

PubMed Central

Lim, Charlemagne Alexander A.; Awan, Tahir Hussain; Sta. Cruz, Pompe C.; Chauhan, Bhagirath Singh

2015-01-01

Ischaemum rugosum Salisb. (Saramolla grass) is a noxious weed of rice that is difficult to control by chemical or mechanical means once established. A study was conducted to determine the effect of light, temperature, salt, drought, flooding, rice residue mulch, burial depth, and pre-emergence herbicides on seed germination and emergence of I. rugosum. Germination was stimulated by light and inhibited under complete darkness. Optimum temperature for germination was 30/20°C (97.5% germination). Germination reduced from 31 to 3.5% when the osmotic potential of the growing medium decreased from -0.1 to -0.6 MPa and no germination occurred at -0.8 MPa. Germination was 18 and 0.5% at 50 and 100 mM NaCl concentrations, respectively, but was completely inhibited at 150 mM or higher. Residue application at 1–6 t ha-1 reduced weed emergence by 35–88% and shoot biomass by 55–95%. The efficacy of pre-emergence herbicides increased with increasing application rates and decreased with increasing rice residue mulching. The efficacy of herbicides was in the order of oxadiazon> pendimethalin> pretilachlor. At 6 t ha-1, all herbicides, regardless of rates, did not differ from the control treatment. I. rugosum seeds buried at 2 cm or deeper did not emerge; however, they emerged by 4.5 and 0.5% at 0.5 and 1 cm depths, respectively, compared to the 39% germination for soil surface seeding. Flooding at 4 DAS or earlier reduced seedling emergence and shoot biomass while flooding at 8 DAS reduced only seedling emergence. The depth and timing of flooding independently reduced root biomass. Flooding at 4 and 6 cm depths reduced the root biomass. Relative to flooding on the day of sowing, flooding at 8 DAS increased root biomass by 89%. Similarly, flooding on the day of sowing and at 2 DAS reduced the root–shoot biomass ratio. Under the no-flood treatment, increasing rates of pretilachlor from 0.075 to 0.3 kg ai ha-1 reduced weed emergence by 61–79%. At the flooding depth of 2�

Influence of Environmental Factors, Cultural Practices, and Herbicide Application on Seed Germination and Emergence Ecology of Ischaemum rugosum Salisb.

PubMed

Lim, Charlemagne Alexander A; Awan, Tahir Hussain; Sta Cruz, Pompe C; Chauhan, Bhagirath Singh

2015-01-01

Ischaemum rugosum Salisb. (Saramolla grass) is a noxious weed of rice that is difficult to control by chemical or mechanical means once established. A study was conducted to determine the effect of light, temperature, salt, drought, flooding, rice residue mulch, burial depth, and pre-emergence herbicides on seed germination and emergence of I. rugosum. Germination was stimulated by light and inhibited under complete darkness. Optimum temperature for germination was 30/20°C (97.5% germination). Germination reduced from 31 to 3.5% when the osmotic potential of the growing medium decreased from -0.1 to -0.6 MPa and no germination occurred at -0.8 MPa. Germination was 18 and 0.5% at 50 and 100 mM NaCl concentrations, respectively, but was completely inhibited at 150 mM or higher. Residue application at 1-6 t ha-1 reduced weed emergence by 35-88% and shoot biomass by 55-95%. The efficacy of pre-emergence herbicides increased with increasing application rates and decreased with increasing rice residue mulching. The efficacy of herbicides was in the order of oxadiazon> pendimethalin> pretilachlor. At 6 t ha-1, all herbicides, regardless of rates, did not differ from the control treatment. I. rugosum seeds buried at 2 cm or deeper did not emerge; however, they emerged by 4.5 and 0.5% at 0.5 and 1 cm depths, respectively, compared to the 39% germination for soil surface seeding. Flooding at 4 DAS or earlier reduced seedling emergence and shoot biomass while flooding at 8 DAS reduced only seedling emergence. The depth and timing of flooding independently reduced root biomass. Flooding at 4 and 6 cm depths reduced the root biomass. Relative to flooding on the day of sowing, flooding at 8 DAS increased root biomass by 89%. Similarly, flooding on the day of sowing and at 2 DAS reduced the root-shoot biomass ratio. Under the no-flood treatment, increasing rates of pretilachlor from 0.075 to 0.3 kg ai ha-1 reduced weed emergence by 61-79%. At the flooding depth of 2-4 cm

Natural variation reveals that OsSAP16 controls low-temperature germination in rice.

PubMed

Wang, Xiang; Zou, Baohong; Shao, Qiaolin; Cui, Yongmei; Lu, Shan; Zhang, Yan; Huang, Quansheng; Huang, Ji; Hua, Jian

2018-01-23

Low temperature affects seed germination in plants, and low-temperature germination (LTG) is an important agronomic trait. Natural variation of LTG has been reported in rice, but the molecular basis for this variation is largely unknown. Here we report the phenotypic analysis of LTG in 187 rice natural accessions and a genome-wide association study (GWAS) of LTG in this collection. A total of 53 quantitative trait loci (QTLs) were found to be associated with LTG, of which 20 were located in previously reported QTLs. We further identified Stress-Associated Protein 16 (OsSAP16), coding for a zinc-finger domain protein, as a causal gene for one of the major LTG QTLs. Loss of OsSAP16 function reduces germination while greater expression of OsSAP16 enhances germination at low temperature. In addition, accessions with extremely high and low LTG values have correspondingly high and low OsSAP16 expression at low temperatures, suggesting that variation in expression of the OsSAP16 gene contributes to LTG variation. As the first case of identification of an LTG gene through GWAS, this study indicates that GWAS of natural accessions is an effective strategy in genetically dissecting LTG processes and gaining molecular understanding of low-temperature response and germination. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

A role for caleosin in degradation of oil-body storage lipid during seed germination.

PubMed

Poxleitner, Marianne; Rogers, Sally W; Lacey Samuels, A; Browse, John; Rogers, John C

2006-09-01

Caleosin is a Ca(2+)-binding oil-body surface protein. To assess its role in the degradation of oil-bodies, two independent insertion mutants lacking caleosin were studied. Both mutants demonstrated significant delay of breakdown of the 20:1 storage lipid at 48 and 60 h of germination. Additionally, although germination rates for seeds were not affected by the mutations, mutant seedlings grew more slowly than wild type when measured at 48 h of germination, a defect that was corrected with continued growth for 72 and 96 h in the light. After 48 h of germination, wild-type central vacuoles had smooth contours and demonstrated internalization of oil bodies and of membrane containing alpha- and delta-tonoplast intrinsic proteins (TIPs), markers for protein storage vacuoles. In contrast, mutant central vacuoles had distorted limiting membranes displaying domains with clumps of the two TIPs, and they contained fewer oil bodies. Thus, during germination caleosin plays a role in the degradation of storage lipid in oil bodies. Its role involves both the normal modification of storage vacuole membrane and the interaction of oil bodies with vacuoles. The results indicate that interaction of oil bodies with vacuoles is one mechanism that contributes to the degradation of storage lipid.

The allelopathic effects of invasive plant Solidago canadensis on seed germination and growth of Lactuca sativa enhanced by different types of acid deposition.

PubMed

Wang, Congyan; Xiao, Hongguang; Zhao, Lulu; Liu, Jun; Wang, Lei; Zhang, Fei; Shi, Yanchun; Du, Daolin

2016-04-01

acid deposition and S. canadensis on seed germination and growth of L. sativa. The ratio of SO4(2-) to NO3(-) in acid deposition was an important factor that profoundly affected the allelopathic effects of S. canadensis on the seed germination and growth of L. sativa possibly because the difference in exchange capacity with hydroxyl groups (OH(-)) between SO4(2-) and NO3(-) as well as the fertilizing effects triggered by nitric deposition. Thus, the allelopathic effects of invasive species on seed germination and growth of native plants might be enhanced under increased and diversified acid deposition.

Differential Effects of Carbohydrates on Arabidopsis Pollen Germination.

PubMed

Hirsche, Jörg; García Fernández, José M; Stabentheiner, Edith; Großkinsky, Dominik K; Roitsch, Thomas

2017-04-01

Pollen germination as a crucial process in plant development strongly depends on the accessibility of carbon as energy source. Carbohydrates, however, function not only as a primary energy source, but also as important signaling components. In a comprehensive study, we analyzed various aspects of the impact of 32 different sugars on in vitro germination of Arabidopsis pollen comprising about 150 variations of individual sugars and combinations. Twenty-six structurally different mono-, di- and oligosaccharides, and sugar analogs were initially tested for their ability to support pollen germination. Whereas several di- and oligosaccharides supported pollen germination, hexoses such as glucose, fructose and mannose did not support and even considerably inhibited pollen germination when added to germination-supporting medium. Complementary experiments using glucose analogs with varying functional features, the hexokinase inhibitor mannoheptulose and the glucose-insensitive hexokinase-deficient Arabidopsis mutant gin2-1 suggested that mannose- and glucose-mediated inhibition of sucrose-supported pollen germination depends partially on hexokinase signaling. The results suggest that, in addition to their role as energy source, sugars act as signaling molecules differentially regulating the complex process of pollen germination depending on their structural properties. Thus, a sugar-dependent multilayer regulation of Arabidopsis pollen germination is supported, which makes this approach a valuable experimental system for future studies addressing sugar sensing and signaling. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Relation between germination and mycelium growth of individual fungal spores.

PubMed

Gougouli, Maria; Koutsoumanis, Konstantinos P

2013-02-15

The relation between germination time and lag time of mycelium growth of individual spores was studied by combining microscopic and macroscopic techniques. The radial growth of a large number (100-200) of Penicillium expansum and Aspergillus niger mycelia originating from single spores was monitored macroscopically at isothermal conditions ranging from 0 to 30°C and 10 to 41.5°C, respectively. The radial growth curve for each mycelium was fitted to a linear model for the estimation of mycelium lag time. The results showed that the lag time varied significantly among single spores. The cumulative frequency distributions of the lag times were fitted to the modified Gompertz model and compared with the respective distributions for the germination time, which were obtained microscopically. The distributions of the measured mycelium lag time were found to be similar to the germination time distributions under the same conditions but shifted in time with the lag times showing a significant delay compared to germination times. A numerical comparison was also performed based on the distribution parameters λ(m) and λ(g), which indicate the time required from the spores to start the germination process and the completion of the lag phase, respectively. The relative differences %(λ(m)-λ(g))/λ(m) were not found to be significantly affected by temperatures tested with mean values of 72.5±5.1 and 60.7±2.1 for P. expansum for A. niger, respectively. In order to investigate the source of the above difference, a time-lapse microscopy method was developed providing videos with the behavior of single fungal spore from germination until mycelium formation. The distances of the apexes of the first germ tubes that emerged from the swollen spore were measured in each frame of the videos and these data were expressed as a function of time. The results showed that in the early hyphal development, the measured radii appear to increase exponentially, until a certain time, where

In Vivo Effects of Barbituates on Seed Germination and Seedling Growth.

ERIC Educational Resources Information Center

Kordan, H. A.

1984-01-01

A simple, low-cost experimental system can be used to demonstrate the "in vivo" effects of barbituates on seed germination and seedling growth behavior in different plant species. Lipid solubility and concentration of individual barbituates both affect the response. List of materials needed, procedures used, and typical results obtained are…

The Effect of Resin and Monoterpenes on Spore Germination and Growth in Fusarium circinatum.

PubMed

Slinski, S L; Zakharov, F; Gordon, T R

2015-01-01

Resin obtained from Pinus radiata and five monoterpene components of resin (limonene, α-pinene, β-pinene, camphene, and myrcene) were tested to determine their effects on mycelial growth and germination and survival of spores of Fusarium circinatum, the cause of pitch canker in pine, and F. temperatum, which is interfertile with F. circinatum but not pathogenic to pine. Averaged across all treatments, F. temperatum sustained the greatest reduction in radial growth (16.9±0.02% of control). The greatest reduction in dry weight also occurred in F. temperatum (11.7±0.01% of control), and all isolates of F. circinatum were significantly less affected (P<0.05). Spore germination rates in a saturated atmosphere of monoterpenes were relatively high for all tested isolates but, when placed in direct contact with resin, spore survival was significantly greater for F. circinatum than for F. temperatum. Our results are consistent with the hypothesis that greater tolerance of resin is one factor distinguishing F. circinatum from the nonpathogenic F. temperatum. However, differential tolerance of monoterpene components of resin is not sufficient to explain the observed variation in virulence to pine in F. circinatum.

Freezing tolerance of conifer seeds and germinants.

PubMed

Hawkins, B J; Guest, H J; Kolotelo, D

2003-12-01

Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation

Evolution of 'smoke' induced seed germination in pyroendemic plants

USGS Publications Warehouse

Keeley, J. E.; Pausas, J.G.

2016-01-01

Pyroendemics are plants in which seedling germination and successful seedling recruitment are restricted to immediate postfire environments. In many fire-prone ecosystems species cue their germination to immediate postfire conditions. Here we address how species have evolved one very specific mechanism, which is using the signal of combustion products from biomass. This is often termed ‘smoke’ stimulated germination although it was first discovered in studies of charred wood effects on germination of species strictly tied to postfire conditions (pyroendemics). Smoke stimulated germination has been reported from a huge diversity of plant species. The fact that the organic compound karrikin (a product of the degradation of cellulose) is a powerful germination cue in many species has led to the assumption that this compound is the only chemical responsible for smoke-stimulated germination. Here we show that smoke-stimulated germination is a complex trait with different compounds involved. We propose that convergent evolution is a more parsimonious model for smoke stimulated germination, suggesting that this trait evolved multiple times in response to a variety of organic and inorganic chemical triggers in smoke. The convergent model is congruent with the evolution of many other fire-related traits.

Identification of HDA15-PIF1 as a key repression module directing the transcriptional network of seed germination in the dark.

PubMed

Gu, Dachuan; Chen, Chia-Yang; Zhao, Minglei; Zhao, Linmao; Duan, Xuewu; Duan, Jun; Wu, Keqiang; Liu, Xuncheng

2017-07-07

Light is a major external factor in regulating seed germination. Photoreceptor phytochrome B (PHYB) plays a predominant role in promoting seed germination in the initial phase after imbibition, partially by repressing phytochrome-interacting factor1 (PIF1). However, the mechanism underlying the PHYB-PIF1-mediated transcription regulation remains largely unclear. Here, we identified that histone deacetylase15 (HDA15) is a negative component of PHYB-dependent seed germination. Overexpression of HDA15 in Arabidopsis inhibits PHYB-dependent seed germination, whereas loss of function of HDA15 increases PHYB-dependent seed germination. Genetic evidence indicated that HDA15 acts downstream of PHYB and represses seed germination dependent on PIF1. Furthermore, HDA15 interacts with PIF1 both in vitro and in vivo. Genome-wide transcriptome analysis revealed that HDA15 and PIF1 co-regulate the transcription of the light-responsive genes involved in multiple hormonal signaling pathways and cellular processes in germinating seeds in the dark. In addition, PIF1 recruits HDA15 to the promoter regions of target genes and represses their expression by decreasing the histone H3 acetylation levels in the dark. Taken together, our analysis uncovered the role of histone deacetylation in the light-regulated seed germination process and identified that HDA15-PIF1 acts as a key repression module directing the transcription network of seed germination. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Karrikins Discovered in Smoke Trigger Arabidopsis Seed Germination by a Mechanism Requiring Gibberellic Acid Synthesis and Light1[W][OA

PubMed Central

Nelson, David C.; Riseborough, Julie-Anne; Flematti, Gavin R.; Stevens, Jason; Ghisalberti, Emilio L.; Dixon, Kingsley W.; Smith, Steven M.

2009-01-01

Discovery of the primary seed germination stimulant in smoke, 3-methyl-2H-furo[2,3-c]pyran-2-one (KAR1), has resulted in identification of a family of structurally related plant growth regulators, karrikins. KAR1 acts as a key germination trigger for many species from fire-prone, Mediterranean climates, but a molecular mechanism for this response remains unknown. We demonstrate that Arabidopsis (Arabidopsis thaliana), an ephemeral of the temperate northern hemisphere that has never, to our knowledge, been reported to be responsive to fire or smoke, rapidly and sensitively perceives karrikins. Thus, these signaling molecules may have greater significance among angiosperms than previously realized. Karrikins can trigger germination of primary dormant Arabidopsis seeds far more effectively than known phytohormones or the structurally related strigolactone GR-24. Natural variation and depth of seed dormancy affect the degree of KAR1 stimulation. Analysis of phytohormone mutant germination reveals suppression of KAR1 responses by abscisic acid and a requirement for gibberellin (GA) synthesis. The reduced germination of sleepy1 mutants is partially recovered by KAR1, which suggests that germination enhancement by karrikin is only partly DELLA dependent. While KAR1 has little effect on sensitivity to exogenous GA, it enhances expression of the GA biosynthetic genes GA3ox1 and GA3ox2 during seed imbibition. Neither abscisic acid nor GA levels in seed are appreciably affected by KAR1 treatment prior to radicle emergence, despite marked differences in germination outcome. KAR1 stimulation of Arabidopsis germination is light-dependent and reversible by far-red exposure, although limited induction of GA3ox1 still occurs in the dark. The observed requirements for light and GA biosynthesis provide the first insights into the karrikin mode of action. PMID:19074625

Factors affecting construction performance: exploratory factor analysis

NASA Astrophysics Data System (ADS)

Soewin, E.; Chinda, T.

2018-04-01

The present work attempts to develop a multidimensional performance evaluation framework for a construction company by considering all relevant measures of performance. Based on the previous studies, this study hypothesizes nine key factors, with a total of 57 associated items. The hypothesized factors, with their associated items, are then used to develop questionnaire survey to gather data. The exploratory factor analysis (EFA) was applied to the collected data which gave rise 10 factors with 57 items affecting construction performance. The findings further reveal that the items constituting ten key performance factors (KPIs) namely; 1) Time, 2) Cost, 3) Quality, 4) Safety & Health, 5) Internal Stakeholder, 6) External Stakeholder, 7) Client Satisfaction, 8) Financial Performance, 9) Environment, and 10) Information, Technology & Innovation. The analysis helps to develop multi-dimensional performance evaluation framework for an effective measurement of the construction performance. The 10 key performance factors can be broadly categorized into economic aspect, social aspect, environmental aspect, and technology aspects. It is important to understand a multi-dimension performance evaluation framework by including all key factors affecting the construction performance of a company, so that the management level can effectively plan to implement an effective performance development plan to match with the mission and vision of the company.

Seed Germination Ecology of Echinochloa glabrescens and Its Implication for Management in Rice (Oryza sativa L.)

PubMed Central

Opeña, Jhoana L.; Chauhan, Bhagirath S.; Baltazar, Aurora M.

2014-01-01

Echinochloa glabrescens is a C4 grass weed that is very competitive with rice when left uncontrolled. The competitive ability of weeds is intensified in direct-seeded rice production systems. A better understanding is needed of factors affecting weed seed germination, which can be used as a component of integrated weed management in direct-seeded rice. This study was conducted to determine the effects of temperature, light, salt and osmotic stress, burial depth, crop residue, time and depth of flooding, and herbicide application on the emergence, survival, and growth of two populations [Nueva Ecija (NE) and Los Baños (IR)] of E. glabrescens. Seeds from both populations germinated at all temperatures. The NE population had a higher germination rate (88%) from light stimulation than did the IR population (34%). The salt concentration and osmotic potential required to inhibit 50% of germination were 313 mM and −0.24 MPa, respectively, for the NE population and 254 mM and −0.33 MPa, respectively, for the IR population. Emergence in the NE population was totally inhibited at 4-cm burial depth in the soil, whereas that of the IR population was inhibited at 8 cm. Compared with zero residue, the addition of 5 t ha−1 of rice residue reduced emergence in the NE and IR populations by 38% and 9%, respectively. Early flooding (within 2 days after sowing) at 2-cm depth reduced shoot growth by 50% compared with non-flooded conditions. Pretilachlor applied at 0.075 kg ai ha−1 followed by shallow flooding (2-cm depth) reduced seedling emergence by 94−96% compared with the nontreated flooded treatment. Application of postemergence herbicides at 4-leaf stage provided 85−100% control in both populations. Results suggest that integration of different strategies may enable sustainable management of this weed and of weeds with similar germination responses. PMID:24642568

[Viability and germination of Hechtia perotensis (Bromeliaceae) seed].

PubMed

Elizalde, Violeta; García, José Rodolfo; Peña-Valdivia, Cecilia Beatriz; Ybarra, Ma Carmen; Leyva, Otto Raúl; Trejo, Carlos

2017-03-01

Endemic populations of Hechtia perotensis have been described in Puebla and Veracruz, Mexico. Good quality seed collections can be used in conservation, research and ecological restoration. To evaluate seed quality of wild and endemic species, some compounds are used as effective promoters of germination, such as potassium nitrate (KNO3) and gibberellic acid (AG3), because they increase seed germination capacity and reduce latency. The triphenyl tetrazolium chloride (tetrazolium) test correlates seed viability because it is based on the activity of dehydrogenases in live tissues that catalyze mitochondrial respiration. The objective of this study was to obtain information on size and weight of capsules and seeds and seed germination and viability of H. perotensis, collected in Veracruz in the year 2012 and 2015. The hypotheses were 1) that seed germination and viability are independent of the year of collection, 2) that there is a tetrazolium concentration that can identify seed viability better than others, and 3) that pretreatment with KNO3 or AG3 improves seed germination. Seed germination was assessed using a completely randomized design with three treatments (control and the germination promoters 0.2 % KNO3 and 500 mg/L AG3), four treatments for the viability test (control, 0.2, 0.5 and 1.0 % of tetrazolium) and six replicates for each treatment. A total of one hundred seeds for germination experiments, and 25 seeds for the viability test were used. The results between and within years were analyzed with ANOVA and multiple comparison with the Tukey test. The proportion of non-germinated seeds was quantified along with the number of normal and abnormal seedlings, seeds with viable embryo, seeds without embryo, and seeds with low or no viability. On average, for the 2012 collected sample, 36 % had viable embryos, 7 % had low viability, 24 % were not viable and 33 % had no embryo. This result was significantly different from the 2015 sample, for which 87 % of

Inference of sigma factor controlled networks by using numerical modeling applied to microarray time series data of the germinating prokaryote.

PubMed

Strakova, Eva; Zikova, Alice; Vohradsky, Jiri

2014-01-01

A computational model of gene expression was applied to a novel test set of microarray time series measurements to reveal regulatory interactions between transcriptional regulators represented by 45 sigma factors and the genes expressed during germination of a prokaryote Streptomyces coelicolor. Using microarrays, the first 5.5 h of the process was recorded in 13 time points, which provided a database of gene expression time series on genome-wide scale. The computational modeling of the kinetic relations between the sigma factors, individual genes and genes clustered according to the similarity of their expression kinetics identified kinetically plausible sigma factor-controlled networks. Using genome sequence annotations, functional groups of genes that were predominantly controlled by specific sigma factors were identified. Using external binding data complementing the modeling approach, specific genes involved in the control of the studied process were identified and their function suggested.

Germinating pokeberry seed (Phytolacca americana L.)

Treesearch

Arnold Krochmal

1970-01-01

The seeds of pokeberry (Phytolacca americana L.) can be germinated successfully by storing them dry over winter and then nicking them with a needle to break the seed coat, followed by germination treatment at about 75ºF.

Germination Under Stress: A Marker For Inherent Vigor Or An Isolated Event?

USDA-ARS?s Scientific Manuscript database

Seedling vigor and its translation to late-season vigor are, at best, murky for most beet breeders. The initial conditions a germinating seed encounters, and its ability to overcome them, affects stored energy reserves to withstand future adverse environments and the ability of the seedling to survi...

Effects of fungal deterioration on grain: nutritional value, toxicity, germination.

PubMed

Sauer, D B

1988-12-01

Moulds or fungi that grow in grains and seeds during storage and transport cause germination decrease, visible mouldiness, discoloration, musty or sour odours, caking, chemical and nutritional changes, reduction in processing quality, and form of mycotoxins. These deteriorative changes affect the grade and price of grain and contribute to customer dissatisfaction when the grain is marketed. The respiration of grain and fungi results in a loss in dry matter as well as the production of heat and moisture which contribute to further spoilage. Net changes in nutritional value and the risk of mycotoxin contamination are difficult to predict because they depend on a complex interaction of factors such as temperature, moisture, storage time, fungal species composition, kind of grain, and previous storage history. Moisture is the most important variable determining the rate of deterioration caused by fungi, with temperature being the second major factor. Problems with deterioration of grain in export shipments are not a recent development. They are related primarily to grain moisture at loading, and also to the extent of previous mould invasion.

DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination.

PubMed

Graeber, Kai; Linkies, Ada; Steinbrecher, Tina; Mummenhoff, Klaus; Tarkowská, Danuše; Turečková, Veronika; Ignatz, Michael; Sperber, Katja; Voegele, Antje; de Jong, Hans; Urbanová, Terezie; Strnad, Miroslav; Leubner-Metzger, Gerhard

2014-08-26

Seed germination is an important life-cycle transition because it determines subsequent plant survival and reproductive success. To detect optimal spatiotemporal conditions for germination, seeds act as sophisticated environmental sensors integrating information such as ambient temperature. Here we show that the delay of germination 1 (DOG1) gene, known for providing dormancy adaptation to distinct environments, determines the optimal temperature for seed germination. By reciprocal gene-swapping experiments between Brassicaceae species we show that the DOG1-mediated dormancy mechanism is conserved. Biomechanical analyses show that this mechanism regulates the material properties of the endosperm, a seed tissue layer acting as germination barrier to control coat dormancy. We found that DOG1 inhibits the expression of gibberellin (GA)-regulated genes encoding cell-wall remodeling proteins in a temperature-dependent manner. Furthermore we demonstrate that DOG1 causes temperature-dependent alterations in the seed GA metabolism. These alterations in hormone metabolism are brought about by the temperature-dependent differential expression of genes encoding key enzymes of the GA biosynthetic pathway. These effects of DOG1 lead to a temperature-dependent control of endosperm weakening and determine the optimal temperature for germination. The conserved DOG1-mediated coat-dormancy mechanism provides a highly adaptable temperature-sensing mechanism to control the timing of germination.

DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination

PubMed Central

Graeber, Kai; Linkies, Ada; Steinbrecher, Tina; Mummenhoff, Klaus; Tarkowská, Danuše; Turečková, Veronika; Ignatz, Michael; Sperber, Katja; Voegele, Antje; de Jong, Hans; Urbanová, Terezie; Strnad, Miroslav; Leubner-Metzger, Gerhard

2014-01-01

Seed germination is an important life-cycle transition because it determines subsequent plant survival and reproductive success. To detect optimal spatiotemporal conditions for germination, seeds act as sophisticated environmental sensors integrating information such as ambient temperature. Here we show that the DELAY OF GERMINATION 1 (DOG1) gene, known for providing dormancy adaptation to distinct environments, determines the optimal temperature for seed germination. By reciprocal gene-swapping experiments between Brassicaceae species we show that the DOG1-mediated dormancy mechanism is conserved. Biomechanical analyses show that this mechanism regulates the material properties of the endosperm, a seed tissue layer acting as germination barrier to control coat dormancy. We found that DOG1 inhibits the expression of gibberellin (GA)-regulated genes encoding cell-wall remodeling proteins in a temperature-dependent manner. Furthermore we demonstrate that DOG1 causes temperature-dependent alterations in the seed GA metabolism. These alterations in hormone metabolism are brought about by the temperature-dependent differential expression of genes encoding key enzymes of the GA biosynthetic pathway. These effects of DOG1 lead to a temperature-dependent control of endosperm weakening and determine the optimal temperature for germination. The conserved DOG1-mediated coat-dormancy mechanism provides a highly adaptable temperature-sensing mechanism to control the timing of germination. PMID:25114251

Effect of day length on germination of seeds collected in Alaska

USGS Publications Warehouse

Densmore, R.V.

1997-01-01

Day length control can effectively limit seed germination to favorable seasons, but this phenomenon has been studied in relatively few wild plants. I tested species from interior Alaska for day length control of germination under controlled conditions, and I also monitored germination phenology in natural habitats. Unstratified and cold-stratified seeds were germinated on short (13 h) and long (22 h) day length and in the dark at constant and alternating temperatures. On long day length, unstratified Ledum decumbens and Saxifraga tricuspidata seeds germinated from 5??C to 20??C, but on short day length few or no seeds germinated at 5??C and 10??C and germination was reduced at higher temperatures. Unstratified seeds of Diapensia lapponica and Chamaedaphne calyculata germinated only at 15??C and 20??C on long day length, and short day length completely inhibited germination. Cold stratification widened the temperature range for germination on both long and short day lengths, but germination was still lower on short than long day length. Germination phenology in natural habitats was consistent with germination in controlled conditions. In these species, short day length and low temperatures interact to inhibit germination in the fall. After overwintering, seeds germinate in the spring at low temperatures and on long day lengths. The inhibitory effect of short day length is not important in the spring because day length is already long at snowmelt.

Germination and root elongation bioassays in six different plant species for testing Ni contamination in soil.

PubMed

Visioli, Giovanna; Conti, Federica D; Gardi, Ciro; Menta, Cristina

2014-04-01

In vitro short-term chronic phytotoxicity germination and root elongation test were applied to test the effects of nickel (Ni) in seed germination and root elongation in six plants species: Cucumis sativus (Cucurbitaceae), Lepidium sativum and Brassica nigra (Brassicaceae), Trifolium alexandrinum and Medicago sativa (Fabaceae), Phacelia tanacetifolia (Boraginaceae). A naturally Ni rich soil was used to compare the results obtained. Unlike root elongation, germination was not affected by Ni in any of the six species tested. EC50 values, calculated on the root elongation, showed that Ni toxicity decreases in the following order: P. tanacetifolia > B. nigra > C. sativus > L. sativum > M. sativa > T. alexandrinum. The test conducted using soil elutriate revealed a significantly lower effect in both seed germination and root elongation when compared to the results obtained using untreated soil. Conversely, the test performed on soil confirmed the high sensitivity of C. sativus, P. tanacetifolia and L. sativum to Ni.

Involvement of Alternative Splicing in Barley Seed Germination

PubMed Central

Zhang, Qisen; Zhang, Xiaoqi; Wang, Songbo; Tan, Cong; Zhou, Gaofeng; Li, Chengdao

2016-01-01

Seed germination activates many new biological processes including DNA, membrane and mitochondrial repairs and requires active protein synthesis and sufficient energy supply. Alternative splicing (AS) regulates many cellular processes including cell differentiation and environmental adaptations. However, limited information is available on the regulation of seed germination at post-transcriptional levels. We have conducted RNA-sequencing experiments to dissect AS events in barley seed germination. We identified between 552 and 669 common AS transcripts in germinating barley embryos from four barley varieties (Hordeum vulgare L. Bass, Baudin, Harrington and Stirling). Alternative 3’ splicing (34%-45%), intron retention (32%-34%) and alternative 5’ splicing (16%-21%) were three major AS events in germinating embryos. The AS transcripts were predominantly mapped onto ribosome, RNA transport machineries, spliceosome, plant hormone signal transduction, glycolysis, sugar and carbon metabolism pathways. Transcripts of these genes were also very abundant in the early stage of seed germination. Correlation analysis of gene expression showed that AS hormone responsive transcripts could also be co-expressed with genes responsible for protein biosynthesis and sugar metabolisms. Our RNA-sequencing data revealed that AS could play important roles in barley seed germination. PMID:27031341

A new role for the Arabidopsis AP2 transcription factor, LEAFY PETIOLE, in gibberellin-induced germination is revealed by the misexpression of a homologous gene, SOB2/DRN-LIKE.

PubMed

Ward, Jason M; Smith, Alison M; Shah, Purvi K; Galanti, Sarah E; Yi, Hankuil; Demianski, Agnes J; van der Graaff, Eric; Keller, Beat; Neff, Michael M

2006-01-01

Gibberellic acid (GA) promotes germination, stem/hypocotyl elongation, and leaf expansion during seedling development. Using activation-tagging mutagenesis, we identified a mutation, sob2-D (for suppressor of phytochromeB-4 [phyB-4]#2 dominant), which suppresses the long-hypocotyl phenotype of a phyB missense allele, phyB-4. This mutant phenotype is caused by the overexpression of an APETALA2 transcription factor, SOB2, also called DRN-like. SOB2/DRN-like transcript is not detectable in wild-type seedling or adult tissues via RT-PCR analysis, suggesting that SOB2/DRN-like may not be involved in seedling development under normal conditions. Adult sob2-D phyB-4 plants have curled leaves and club-like siliques, resembling plants that overexpress a closely related gene, LEAFY PETIOLE (LEP). Hypocotyls of a LEP-null allele, lep-1, are shorter in the light and dark, suggesting LEP involvement in seedling development. This aberrant hypocotyl phenotype is due at least in part to a delay in germination. In addition, lep-1 is less responsive to GA and more sensitive to the GA biosynthesis inhibitor paclobutrazol, indicating that LEP is a positive regulator of GA-induced germination. RT-PCR shows that LEP transcript accumulates in wild-type seeds during imbibition and germination, and the transcript levels of REPRESSOR OF ga1-3-LIKE2 (RGL2), a negative regulator of GA signaling during germination, is unaffected in lep-1. These results suggest LEP is a positive regulator of GA-induced germination acting independently of RGL2. An alternative model places LEP downstream of RGL2 in the GA-signaling cascade.

Factors affecting acorn production and germination and early growth of seedlings and seedling sprouts

Treesearch

David F. Olson; Stephen G. Boyce

1971-01-01

Acorn production is extremely variable and unpredictable. Flowering is copious, but many climatic factors influence acorn development from initiation of flowers to acorn maturity. Acorns are consumed by birds, animals, insects, and microorganisms. The establishment of seedlings is more closely related to favorable site factors than to size of crops. A majority of oaks...

Factors Affecting Medical Service Quality.

PubMed

Mosadeghrad, Ali Mohammad

2014-02-01

A better understanding of factors influencing quality of medical service can pinpoint better strategies for quality assurance in medical services. This study aimed to identify factors affecting the quality of medical services provided by Iranian physicians. Exploratory in-depth individual interviews were conducted with sixty-four physicians working in various medical institutions in Iran. Individual, organizational and environmental factors enhance or inhibit the quality of medical services. Quality of medical services depends on the personal factors of the physician and patient, and factors pertaining to the healthcare setting and the broader environment. Differences in internal and external factors such as availability of resources, patient cooperation and collaboration among providers affect the quality of medical services and patient outcomes. Supportive leadership, proper planning, education and training and effective management of resources and processes improve the quality of medical services. This article contributes to healthcare theory and practice by developing a conceptual framework for understanding factors that influence medical services quality.

Proteome analysis of Norway maple (Acer platanoides L.) seeds dormancy breaking and germination: influence of abscisic and gibberellic acids

PubMed Central

Pawłowski, Tomasz A

2009-01-01

Background Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid) and growth promoters (e.g. gibberellins) is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process. Results A proteomic approach was used to analyse the mechanism of dormancy breaking in Norway maple seeds caused by cold stratification, and the participation of the abscisic (ABA) and gibberellic (GA) acids. Forty-four proteins showing significant changes were identified by mass spectrometry. Of these, eight spots were identified as water-responsive, 18 spots were ABA- and nine GA-responsive and nine spots were regulated by both hormones. The classification of proteins showed that most of the proteins associated with dormancy breaking in water were involved in protein destination. Most of the ABA- and GA-responsive proteins were involved in protein destination and energy metabolism. Conclusion In this study, ABA was found to mostly down-regulate proteins whereas GA up-regulated proteins abundance. Most of the changes were observed at the end of stratification in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent state to germination. Seed

Proteome analysis of Norway maple (Acer platanoides L.) seeds dormancy breaking and germination: influence of abscisic and gibberellic acids.

PubMed

Pawłowski, Tomasz A

2009-05-04

Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid) and growth promoters (e.g. gibberellins) is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process. A proteomic approach was used to analyse the mechanism of dormancy breaking in Norway maple seeds caused by cold stratification, and the participation of the abscisic (ABA) and gibberellic (GA) acids. Forty-four proteins showing significant changes were identified by mass spectrometry. Of these, eight spots were identified as water-responsive, 18 spots were ABA- and nine GA-responsive and nine spots were regulated by both hormones. The classification of proteins showed that most of the proteins associated with dormancy breaking in water were involved in protein destination. Most of the ABA- and GA-responsive proteins were involved in protein destination and energy metabolism. In this study, ABA was found to mostly down-regulate proteins whereas GA up-regulated proteins abundance. Most of the changes were observed at the end of stratification in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent state to germination. Seed dormancy breaking involves

Linking seed germination and plant height: a case study of a wetland community on the eastern Tibet Plateau.

PubMed

Liu, Kun; Cao, Suzhen; Du, Guozhen; Baskin, Jerry M; Baskin, Carol C; Bu, Haiyan; Qi, Wei; Liang, Ting

2018-05-20

Seed germination is the earliest trait expressed in a plant's life history, and it can directly affect the expression of post germination traits. Plant height is central to plant ecological strategies, because it is a major determinant of the ability of a species to compete for light. Thus, linking seed germination and plant height at the community level is very important to understanding plant fitness and community structure. Here, we tested storage condition and temperature requirements for germination of 31 species from a wetland plant community on the eastern Tibet Plateau, and analyzed correlation of germination traits with plant height in relation to storage condition. Germination percentage was positively related to plant height, and this relationship disappeared when seeds were incubated at a low temperature (i.e. 5°C) or after they were stored under wet-cold conditions. The response of seeds to dry+wet-cold storage was negatively related to plant height. Based on the scores of each species on the first two principal components derived from PCA, species were classified into two categories by Hierarchical Clustering, and there was a significant difference between germination and plant height of species in these two categories. These results suggest that the requirements for seed germination together with seasonal change in environmental conditions determine the window for germination and in turn plant growth season and resource utilization and ultimately plant height. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Germination temperatures for container culture of southern pines

Treesearch

James P. Barnett

1979-01-01

Peak germination of unstratified longleaf, shortleaf, loblolly, and slash pine seeds occurred at 75° F. Longleaf seeds germinated better at lower temperatures and less successfully at higher temperatures than those of slash, loblolly, and shortleaf pine. Stratification broadened the range at which slash, loblolly, and shortleaf germinated satisfactorily. Improvement...

Glutathione synthesis is essential for pollen germination in vitro

PubMed Central

2011-01-01

Background The antioxidant glutathione fulfills many important roles during plant development, growth and defense in the sporophyte, however the role of this important molecule in the gametophyte generation is largely unclear. Bioinformatic data indicate that critical control enzymes are negligibly transcribed in pollen and sperm cells. Therefore, we decided to investigate the role of glutathione synthesis for pollen germination in vitro in Arabidopsis thaliana accession Col-0 and in the glutathione deficient mutant pad2-1 and link it with glutathione status on the subcellular level. Results The depletion of glutathione by buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis, reduced pollen germination rates to 2-5% compared to 71% germination in wildtype controls. The application of reduced glutathione (GSH), together with BSO, restored pollen germination and glutathione contents to control values, demonstrating that inhibition of glutathione synthesis is responsible for the decrease of pollen germination in vitro. The addition of indole-3-acetic acid (IAA) to media containing BSO restored pollen germination to control values, which demonstrated that glutathione depletion in pollen grains triggered disturbances in auxin metabolism which led to inhibition of pollen germination. Conclusions This study demonstrates that glutathione synthesis is essential for pollen germination in vitro and that glutathione depletion and auxin metabolism are linked in pollen germination and early elongation of the pollen tube, as IAA addition rescues glutathione deficient pollen. PMID:21439079

Effects of Autumn and Spring Heat Waves on Seed Germination of High Mountain Plants.

PubMed

Orsenigo, Simone; Abeli, Thomas; Rossi, Graziano; Bonasoni, Paolo; Pasquaretta, Cristian; Gandini, Maurizia; Mondoni, Andrea

2015-01-01

Alpine plants are considered to be particularly vulnerable to climate change and related extreme episodes, such as heat waves. Despite growing interest in the impact of heat waves on alpine plants, knowledge about their effects on regeneration is still fragmentary. Recruitment from seeds will be crucial for the successful migration and survival of these species and will play a key role in their future adaptation to climate change. In this study, we assessed the impacts of heat waves on the seed germination of 53 high mountain plants from the Northern Apennines (Italy). The seeds were exposed to laboratory simulations of three seasonal temperature treatments, derived from real data recorded at a meteorological station near the species growing site, which included two heat wave episodes that occurred both in spring 2003 and in autumn 2011. Moreover, to consider the effect of increasing drought conditions related to heat waves, seed germination was also investigated under four different water potentials. In the absence of heat waves, seed germination mainly occurred in spring, after seeds had experienced autumn and winter seasons. However, heat waves resulted in a significant increase of spring germination in c. 30% of the species and elicited autumn germination in 50%. When heat waves were coupled with drought, seed germination decreased in all species, but did not stop completely. Our results suggest that in the future, heat waves will affect the germination phenology of alpine plants, especially conditionally dormant and strictly cold-adapted chorotypes, by shifting the emergence time from spring to autumn and by increasing the proportion of emerged seedlings. The detrimental effects of heat waves on recruitment success is less likely to be due to the inhibition of seed germination per se, but rather due to seedling survival in seasons, and temperature and water conditions that they are not used to experiencing. Changes in the proportion and timing of emergence

Effects of Autumn and Spring Heat Waves on Seed Germination of High Mountain Plants

PubMed Central

Orsenigo, Simone; Abeli, Thomas; Rossi, Graziano; Bonasoni, Paolo; Pasquaretta, Cristian; Gandini, Maurizia; Mondoni, Andrea

2015-01-01

Alpine plants are considered to be particularly vulnerable to climate change and related extreme episodes, such as heat waves. Despite growing interest in the impact of heat waves on alpine plants, knowledge about their effects on regeneration is still fragmentary. Recruitment from seeds will be crucial for the successful migration and survival of these species and will play a key role in their future adaptation to climate change. In this study, we assessed the impacts of heat waves on the seed germination of 53 high mountain plants from the Northern Apennines (Italy). The seeds were exposed to laboratory simulations of three seasonal temperature treatments, derived from real data recorded at a meteorological station near the species growing site, which included two heat wave episodes that occurred both in spring 2003 and in autumn 2011. Moreover, to consider the effect of increasing drought conditions related to heat waves, seed germination was also investigated under four different water potentials. In the absence of heat waves, seed germination mainly occurred in spring, after seeds had experienced autumn and winter seasons. However, heat waves resulted in a significant increase of spring germination in c. 30% of the species and elicited autumn germination in 50%. When heat waves were coupled with drought, seed germination decreased in all species, but did not stop completely. Our results suggest that in the future, heat waves will affect the germination phenology of alpine plants, especially conditionally dormant and strictly cold-adapted chorotypes, by shifting the emergence time from spring to autumn and by increasing the proportion of emerged seedlings. The detrimental effects of heat waves on recruitment success is less likely to be due to the inhibition of seed germination per se, but rather due to seedling survival in seasons, and temperature and water conditions that they are not used to experiencing. Changes in the proportion and timing of emergence

Methylglyoxal inhibits seed germination and root elongation and up-regulates transcription of stress-responsive genes in ABA-dependent pathway in Arabidopsis.

PubMed

Hoque, T S; Uraji, M; Tuya, A; Nakamura, Y; Murata, Y

2012-09-01

Methylglyoxal (MG) is a highly reactive metabolite derived from glycolysis. In this study, we examined the effect of MG on seed germination, root elongation, chlorosis and stress-responsive gene expression in Arabidopsis using an abscisic acid (ABA)-deficient mutant, aba2-2. In the wild type, 0.1 mm MG did not affect germination but delayed root elongation, whereas 1.0 mm MG inhibited germination and root elongation and induced chlorosis. MG increased transcription levels of RD29B and RAB18 in a dose-dependent manner but did not affect RD29A transcription level. In contrast, in the aba2-2 mutant, MG inhibition of seed germination at 1.0 mm and 10.0 mm and a delay of root elongation at 0.1 mm MG were mitigated, although there was no significant difference in chlorosis between the wild type and mutant. Moreover, the aba2-2 mutation impaired MG-induced RD29B and RAB18 gene expression. These observations suggest that MG not only directly inhibits germination and root elongation but also indirectly modulates these processes via endogenous ABA in Arabidopsis. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

[Study on conditions of seed germination of Cistanche].

PubMed

Qiao, Xue-Yi; Wang, Hua-Lei; Guo, Yu-Hai

2007-09-01

To study the effect of fluridone concentration, stimulating period, temperature and salt on the seed germination of three species of Cistanche. The seeds were cultured in Petri dish, and the germination percentage was counted. The highest germination percentage was observed in Cistanche tubulosa, C. deserticola, C. sala seeds pre-treated by 0.1 mg x L(-1) fluridone for 24-29 h. The optimal temperature for the seeds germination of three species of Cistanche was at 20-30 degrees C, and the seeds did not germinate at sub-or supraoptimal temperatures (5 and 35 degrees C). The salt tolerance of C. sala seeds was strong, and the critical value of NaCl concentration was 0.04 mol x L(-1). By contrast, C. tubulosa and C. deserticola seeds were more sensitive to the salt stress, the critical value of NaCl concentration was 0.02 mol x L(-1). The optimal germination condition and the method of testing germination percentage of three species of Cistanche seeds are as follow: the seeds are pre-treated by 0.1 mg x L(-1) fluridone for 24 h and then cultured at 20-30 degrees C in salt solution which concentration is lower than 0.02 mol x L(-1).

Activities That Increase Germination and Establishment of Longleaf Pine Seedlings in Containers

Treesearch

James P. Barnett

2002-01-01

Critical to the successful production of longleaf pine (Pinus palustris Mill.) container stock is use of high quality seeds that are properly prepared and sown. Uniformity in germination and establishment in containers makes nursery production easier and more profitable for the grower. Activities that affect seedling performance include: time of seed...

ABA-dependent inhibition of the ubiquitin proteasome system during germination at high temperature in Arabidopsis.

PubMed

Chiu, Rex Shun; Pan, Shiyue; Zhao, Rongmin; Gazzarrini, Sonia

2016-12-01

During germination, endogenous and environmental factors trigger changes in the transcriptome, translatome and proteome to break dormancy. In Arabidopsis thaliana, the ubiquitin proteasome system (UPS) degrades proteins that promote dormancy to allow germination. While research on the UPS has focused on the identification of proteasomal substrates, little information is known about the regulation of its activity. Here we characterized the activity of the UPS during dormancy release and maintenance by monitoring protein ubiquitination and degradation of two proteasomal substrates: Suc-LLVY-AMC, a well characterized synthetic substrate, and FUSCA3 (FUS3), a dormancy-promoting transcription factor degraded by the 26S proteasome. Our data indicate that proteasome activity and protein ubiquitination increase during imbibition at optimal temperature (21°C), and are required for seed germination. However, abscisic acid (ABA) and supraoptimal temperature (32°C) inhibit germination by dampening both protein ubiquitination and proteasome activity. Inhibition of UPS function by high temperature is reduced by the ABA biosynthesis inhibitor, fluridone, and in ABA biosynthetic mutants, suggesting that it is ABA dependent. Accordingly, inhibition of FUS3 degradation at 32°C is also dependent on ABA. Native gels show that inhibition of proteasome activity is caused by interference with the 26S/30S ratio as well as free 19S and 20S levels, impacting the proteasome degradation cycle. Transfer experiments show that ABA-mediated inhibition of proteasome activity at 21°C is restricted to the first 2 days of germination, a time window corresponding to seed sensitivity to environmental and ABA-mediated growth inhibition. Our data show that ABA and high temperature inhibit germination under unfavourable growth conditions by repressing the UPS. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

The effects of smoke derivatives on in vitro seed germination and development of the leopard orchid Ansellia africana.

PubMed

Papenfus, H B; Naidoo, D; Pošta, M; Finnie, J F; Van Staden, J

2016-03-01

Plant-derived smoke and smoke-isolated compounds stimulate germination in seeds from over 80 genera. It has also been reported that smoke affects overall plant vigour and has a stimulatory effect on pollen growth. The effect of smoke on orchid seeds, however, has not been assessed. In South Africa, orchid seeds from several genera may be exposed to smoke when they are released from their seedpods. It is therefore possible that smoke may affect their germination and growth. Therefore, the effects of smoke [applied as smoke-water (SW)] and two smoke-derived compounds, karrikinolide (KAR1 ) and trimethylbutenolide (TMB), were investigated on the germination and growth of orchid seeds in vitro. The effect of SW, KAR1 and TMB were investigated on the endangered epiphytic orchid, Ansellia africana, which is indigenous to tropical areas of Africa. Smoke-water, KAR1 and TMB were infused in half-strength MS medium. The number of germinated seeds and number of seeds and protocorm bodies to reach predetermined developmental stages were recorded on a weekly basis using a dissecting microscope for a 13-week period. Infusing SW 1:250 (v:v) into half-strength MS medium significantly increased the germination rate index (GRI) and the development rate index (DRI) of the A. africana seeds. All the SW treatments significantly increased the number of large protocorm bodies at the final stage of development. Infusing KAR1 into the growing medium had no significant effect on germination or development of the seeds. The TMB treatment, however, significantly reduced the GRI and DRI of A. africana seeds. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effect of fungicide on Wyoming big sagebrush seed germination

USDA-ARS?s Scientific Manuscript database

Because fungal infection may complicate both the logistics and the interpretation of germination tests, seeds are sometimes treated with chemical fungicides. Fungicides may reduce the germination rate and/or germination percentage, and should be avoided unless fungal contamination is severe enough ...

Moistening and heating improve germination of two legume species

Treesearch

C.A. Segelquist

1971-01-01

Germination of Lespedeza cuneata and Desmodium pauciflorum seeds from eastern Oklahoma was increased by heating them under moist conditions. Seeds of Desmodium sessilifolium from the same area germinated well without treatment. Moistening and heating did not increase germination of Lespedeza...

Karrikins: Regulators Involved in Phytohormone Signaling Networks during Seed Germination and Seedling Development

PubMed Central

Meng, Yongjie; Shuai, Haiwei; Luo, Xiaofeng; Chen, Feng; Zhou, Wenguan; Yang, Wenyu; Shu, Kai

2017-01-01

Seed germination and early seedling establishment are critical stages during a plant’s life cycle. These stages are precisely regulated by multiple internal factors, including phytohormones and environmental cues such as light. As a family of small molecules discovered in wildfire smoke, karrikins (KARs) play a key role in various biological processes, including seed dormancy release, germination regulation, and seedling establishment. KARs show a high similarity with strigolactone (SL) in both chemical structure and signaling transduction pathways. Current evidence shows that KARs may regulate seed germination by mediating the biosynthesis and/or signaling transduction of abscisic acid (ABA), gibberellin (GA) and auxin [indoleacetic acid (IAA)]. Interestingly, KARs regulate seed germination differently in different species. Furthermore, the promotion effect on seedling establishment implies that KARs have a great potential application in alleviating shade avoidance response, which attracts more and more attention in plant molecular biology. In these processes, KARs may have complicated interactions with phytohormones, especially with IAA. In this updated review, we summarize the current understanding of the relationship between KARs and SL in the chemical structure, signaling pathway and the regulation of plant growth and development. Further, the crosstalk between KARs and phytohormones in regulating seed germination and seedling development and that between KARs and IAA during shade responses are discussed. Finally, future challenges and research directions for the KAR research field are suggested. PMID:28174573

Implicitly defined criteria for vector optimization in technological process of hydroponic germination of wheat grain

NASA Astrophysics Data System (ADS)

Koneva, M. S.; Rudenko, O. V.; Usatikov, S. V.; Bugaets, N. A.; Tereshchenko, I. V.

2018-05-01

To reduce the duration of the process and to ensure the microbiological purity of the germinated material, an improved method of germination has been developed based on the complex use of physical factors: electrochemically activated water (ECHA-water), electromagnetic field of extremely low frequencies (EMF ELF) with round-the-clock artificial illumination by LED lamps. The increase in the efficiency of the "numerical" technology for solving computational problems of parametric optimization of the technological process of hydroponic germination of wheat grains is considered. In this situation, the quality criteria are contradictory and part of them is given by implicit functions of many variables. A solution algorithm is offered without the construction of a Pareto set in which a relatively small number of elements of a set of alternatives is used to obtain a linear convolution of the criteria with given weights, normalized to their "ideal" values from the solution of the problems of single-criterion private optimizations. The use of the proposed mathematical models describing the processes of hydroponic germination of wheat grains made it possible to intensify the germination process and to shorten the time of obtaining wheat sprouts "Altayskaya 105" for 27 hours.

Cadmium effects on embryo growth of pea seeds during germination: Investigation of the mechanisms of interference of the heavy metal with protein mobilization-related factors.

PubMed

Jaouani, Khadija; Karmous, Inès; Ostrowski, Maciej; Ferjani, Ezzedine El; Jakubowska, Anna; Chaoui, Abdelilah

2018-04-16

This work aims to give more insight into mechanisms of action of cadmium (Cd) on germinating pea seeds (Pisum sativum L. var. douce province), specifically the different ways by which Cd cations may interfere with the principal factors involved during germination process, notably storage proteins mobilization, amino acids freeing and proteolytic activities. Obtained results revealed that the process of hydrolysis of main storage proteins showed a significant disruption, which resulted in the decrease of the release of free amino acids, thus imposing a lack in nitrogen supply of essential nutrients to growing embryo under Cd stress. This hypothesis was evidenced by Cd-induced changes occurring in main purified protein fractions; Albumins, Legumins and Vicilins, during their breakdown. Besides, at enzymatic level, the activities of main proteases responsible for this hydrolysis were altered. Indeed, assays using synthetic substrates and specific protease inhibitors followed by protease activity measurements demonstrated that Cd inhibited drastically the total azocaseinolytic activity (ACA) and activities of different proteolytic classes: cysteine-, aspartic-, serine- and metallo-endopeptidases (EP), leucine- and proline-aminopeptidases (LAP and PAP, respectively), and glycine-carboxypeptidases (Gly-CP). The data here presented may suggest that the vulnerability of the embryonic axes towards Cd toxicity could be explained as a result of eventual disruption of metabolic pathways that affect mobilization of reserves and availability of nutrients. In vitro studies suggest that Cd cations may act either directly on the catalytic sites of the proteolytic enzymes, which may cause their deactivation, or indirectly via the generation of oxidative stress and overproduction of free radicals that can interact with enzymes, by altering their activity and structure. Copyright © 2018 Elsevier GmbH. All rights reserved.

Seed germination strategies: an evolutionary trajectory independent of vegetative functional traits

PubMed Central

Hoyle, Gemma L.; Steadman, Kathryn J.; Good, Roger B.; McIntosh, Emma J.; Galea, Lucy M. E.; Nicotra, Adrienne B.

2015-01-01

Seed germination strategies vary dramatically among species but relatively little is known about how germination traits correlate with other elements of plant strategy systems. Understanding drivers of germination strategy is critical to our understanding of the evolutionary biology of plant reproduction.We present a novel assessment of seed germination strategies focussing on Australian alpine species as a case study. We describe the distribution of germination strategies and ask whether these are correlated with, or form an independent axis to, other plant functional traits. Our approach to describing germination strategy mimicked realistic temperatures that seeds experience in situ following dispersal. Strategies were subsequently assigned using an objective clustering approach. We hypothesized that two main strategies would emerge, involving dormant or non-dormant seeds, and that while these strategies would be correlated with seed traits (e.g., mass or endospermy) they would be largely independent of vegetative traits when analysed in a phylogenetically structured manner.Across all species, three germination strategies emerged. The majority of species postponed germination until after a period of cold, winter-like temperatures indicating physiological and/or morphological dormancy mechanisms. Other species exhibited immediate germination at temperatures representative of those at dispersal. Interestingly, seeds of an additional 13 species “staggered” germination over time. Germination strategies were generally conserved within families. Across a broad range of ecological traits only seed mass and endospermy showed any correlation with germination strategy when phylogenetic relatedness was accounted for; vegetative traits showed no significant correlations with germination strategy. The results indicate that germination traits correlate with other aspects of seed ecology but form an independent axis relative to vegetative traits. PMID:26528294

Cold tolerance in rice germinating seeds revealed by deep RNAseq analysis of contrasting indica genotypes.

PubMed

Dametto, Andressa; Sperotto, Raul A; Adamski, Janete M; Blasi, Édina A R; Cargnelutti, Denise; de Oliveira, Luiz F V; Ricachenevsky, Felipe K; Fregonezi, Jeferson N; Mariath, Jorge E A; da Cruz, Renata P; Margis, Rogério; Fett, Janette P

2015-09-01

Rice productivity is largely affected by low temperature, which can be harmful throughout plant development, from germination to grain filling. Germination of indica rice cultivars under cold is slow and not uniform, resulting in irregular emergence and small plant population. To identify and characterize novel genes involved in cold tolerance during the germination stage, two indica rice genotypes (sister lines previously identified as cold-tolerant and cold-sensitive) were used in parallel transcriptomic analysis (RNAseq) under cold treatment (seeds germinating at 13 °C for 7 days). We detected 1,361 differentially expressed transcripts. Differences in gene expression found by RNAseq were confirmed for 11 selected genes using RT-qPCR. Biological processes enhanced in the cold-tolerant seedlings include: cell division and expansion (confirmed by anatomical sections of germinating seeds), cell wall integrity and extensibility, water uptake and membrane transport capacity, sucrose synthesis, generation of simple sugars, unsaturation of membrane fatty acids, wax biosynthesis, antioxidant capacity (confirmed by histochemical staining of H2O2), and hormone and Ca(2+)-signaling. The cold-sensitive seedlings respond to low temperature stress increasing synthesis of HSPs and dehydrins, along with enhanced ubiquitin/proteasome protein degradation pathway and polyamine biosynthesis. Our findings can be useful in future biotechnological approaches aiming to cold tolerance in indica rice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Nuclear dynamics during ascospore germination in Sordaria macrospora.

PubMed

Teichert, Ines

2017-01-01

The ascomycete Sordaria macrospora has a long history as a model organism for studying fungal sexual development. Starting from an ascospore, sexual fruiting bodies (perithecia) develop within seven days and discharge new ascospores. Sexual development has been studied in detail, revealing genes required for perithecium formation and ascospore germination. However, the germination process per se has not yet been examined. Here I analyze nuclear dynamics during ascospore germination using a fluorescently labeled histone. Live-cell imaging revealed that nuclei are transported into germination vesicles that form on one side of the spore. Polar growth is established from these vesicles. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of magnetic field on seed germination and seedling growth of sunflower

NASA Astrophysics Data System (ADS)

Matwijczuk, A.; Kornarzyński, K.; Pietruszewski, S.

2012-07-01

The impact of a variable magnetic field, magnetically treated water and a combination of both these factors on the germination of seeds and the final mass at the initial stage of growth sunflower plants was presented. Investigations were carried out in pots filled with sand, tin an air-conditioned plant house with no access to daylight using fluorescent light as illumination. A statistical significance positive impact was achieved for the samples subjected to the interaction of both stimulating factors simultaneously, the magnetic field and the impact of treated water several times on the speed of seed germination and final plant mass. Negative impacts were obtained for the majority of the test cases, for the magnetically treated water, the short duration of activity of the magnetic field and for the connection of the magnetic field and low-flow times.

Secondary metabolites profiles and antioxidant activities of germinated brown and red rice

NASA Astrophysics Data System (ADS)

Nurnaistia, Y.; Aisyah, S.; Munawaroh, H. S. H.; Zackiyah

2018-05-01

The research aims to investigate the effect of germination on the secondary metabolite profiles and antioxidant activity of brown and red rice. The germination was performed by using a simple laboratory-scale machine that was designed and optimized to provide conditions that support the germination process. The germination was carried out for 2 days in dark conditions at 26°C and 99% humidity. Analysis of the secondary metabolite profile of ungerminated and germinated rice was performed using LC-MS. The antioxidant activities of ungerminated and germinated rice were done by using DPPH method. The results showed that the profiles of secondary metabolites of brown and red rice changed after germination. Some peaks were found to be induced in the germinated rice. However, some peaks were also loss during germination. The antioxidant activity of brown rice was slightly increased due to the germination, from 11.2% to 22.5%. Meanwhile the antioxidant activity of red rice was decreased after germination, from 73.8% to 60.0%.

Conidial germination patterns in powdery mildews.

PubMed

Cook, R T A; Braun, U

2009-05-01

Four conidial germination types namely, polygoni (syn. Pseudoidium), cichoracearum (syn. Reticuloidium), pannosa (syn. Fibroidium) and fuliginea (syn. Magnicellulatae) are commonly used as an aid in the identification of the Oidium anamorphs of powdery mildews. However, results of germination tests and a survey of the literature showed that these types did not adequately distinguish all taxa and did not reflect the range of species covered. Hence two new main types, Striatoidium and Blumeria, are proposed for the newly created genus Neoerysiphe and for the unique pattern of B. graminis. Two new names, orthotubus and brevitubus subtypes of Fibroidium, are proposed for the pannosa and fuliginea types respectively. Also proposed is a special longitubus pattern for the long, undifferentiated, negatively hydrotropic germ tubes prevalent in Erysiphe trifolii and species in Golovinomyces sect. Depressi. The recognition of the Striatoidium type of N. galeopsidis as distinct from the Pseudoidium type of E. elevata facilitated the detection of a simultaneous infection of Catalpa by these two powdery mildews. A key is provided for the identification of Oidium genera based on germination types. A review of germination patterns in the tribe Phyllactinieae found no consistent differences amongst the genera. Golovinomyces sect. Depressi is re-described to accommodate Golovinomyces spp. often having a longitubus pattern of germination. It includes G. cichoracearum var. latisporus, now considered a separate species based on its germination type, other anamorphic morphology and previous molecular sequence analyses. A new combination, Golovinomyces ambrosiae, is proposed for this species. Other anomalies within G. cichoracearum s. lat. were addressed by proposing another new combination, G. fischeri for the former G. cichoracearum var. fischeri that differs from G. cichoracearum s. str. in having larger chasmothecia and a well distinguished anamorph, and by proposing a new species, G

Proteomic Analysis of Lettuce Seed Germination and Thermoinhibition by Sampling of Individual Seeds at Germination and Removal of Storage Proteins by Polyethylene Glycol Fractionation1

PubMed Central

Song, Bin-Yan; Deng, Zhi-Jun; Wang, Yue; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

2015-01-01

Germination and thermoinhibition in lettuce (Lactuca sativa ‘Jianyexianfeng No. 1’) seeds were investigated by a proteomic comparison among dry seeds, germinated seeds at 15°C, at 15°C after imbibition at 25°C for 48 h, or at 25°C in KNO3 (all sampled individually at germination), and ungerminated seeds at 25°C, a thermoinhibitory temperature. Before two-dimensional gel electrophoresis analysis, storage proteins (greater than 50% of total extractable protein) were removed by polyethylene glycol precipitation, which significantly improved the detection of less abundant proteins on two-dimensional gels. A total of 108 protein spots were identified to change more than 2-fold (P < 0.05) in abundance in at least one germination treatment. Nineteen proteins increasing and one protein decreasing in abundance during germination had higher abundance in germinated 15°C, 15°C after imbibition at 25°C for 48 h, and 25°C in KNO3 seeds than in ungerminated 25°C seeds. Gene expression of 12 of those proteins correlated well with the protein accumulation. Methionine metabolism, ethylene production, lipid mobilization, cell elongation, and detoxification of aldehydes were revealed to be potentially related to lettuce seed germination and thermoinhibition. Accumulation of three proteins and expression of five genes participating in the mevalonate (MVA) pathway of isoprenoid biosynthesis correlated positively with seed germinability. Inhibition of this pathway by lovastatin delayed seed germination and increased the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination and thermoinhibition. PMID:25736209

Mechanisms of Bacterial Spore Germination and Its Heterogeneity

DTIC Science & Technology

2015-01-10

mathematical model describing spore germination has been developed; 9) much of the work above has been extended to Clostridium spores; and 10) ~90...germination. C) Faeder lab, with Li and Setlow labs. We have developed a mathematical model of bacterial spore germination that accounts for...heterogeneity in both Tlag and commitment times. The model is built from three main mathematical components: a receptor distribution function

Striga seed-germination activity of root exudates and compounds present in stems of Striga host and nonhost (trap crop) plants is reduced due to root colonization by arbuscular mycorrhizal fungi.

PubMed

Lendzemo, V; Kuyper, T W; Vierheilig, H

2009-06-01

Root colonization by arbuscular mycorrhizal (AM) fungi reduces stimulation of seed germination of the plant parasite Striga (Orobanchaceae). This reduction can affect not only host plants for Striga, resulting in a lower parasite incidence, but also false hosts or trap crops, which induce suicidal Striga seed germination, thereby diminishing their effectiveness. In order to better understand these AM-induced effects, we tested the influence of root colonization by different AM fungi on the seed-germination activity of root exudates of the Striga hermonthica nonhost plants cowpea and cotton on S. hermonthica. We also tested the effect of AM fungi on the seed-germination activity of the Striga gesnerioides host plant cowpea on S. gesnerioides. Moreover, we studied whether mycorrhization affects the transport of seed-germination activity to above-ground plant parts. Mycorrhization not only resulted in a lower seed germination of S. gesnerioides in the presence of root exudates of the S. gesnerioides host cowpea but also seed germination of S. hermonthica was also lower in the presence of root exudates of the S. hermonthica nonhosts cowpea and cotton. Downregulation of the Striga seed-germination activity occurs not only in root exudates upon root colonization by different AM fungi but also in the compounds produced by stems. The lowered seed-germination activity does not appear to depend on the presence of seed germination inhibitors in the root exudates of mycorrhizal plants. The implication for Striga control in the field is discussed.

Germination behaviour of annual plants under changing climatic conditions: separating local and regional environmental effects.

PubMed

Petrů, Martina; Tielbörger, Katja

2008-04-01

The role of local adaptation and factors other than climate in determining extinction probabilities of species under climate change has not been yet explicitly studied. Here we performed a field experiment with annual plants growing along a steep climatic gradient in Israel to isolate climatic effects for local trait expression. The focus trait was seed dormancy, for which many theoretical predictions exist regarding climate-driven optimal germination behaviour. We evaluated how germination is consistent with theory, indicating local adaptation to current and changing climatic conditions, and how it varies among species and between natural and standardised soil conditions. We reciprocally sowed seeds from three or four origins for each of three annual species, Biscutella didyma, Bromus fasciculatus and Hymenocarpos circinnatus, in their home and neighbouring sowing locations along an aridity gradient. Our predictions were: lower germination fraction for seeds from more arid origins, and higher germination at wetter sowing locations for all seed origins. By sowing seeds in both local and standard soil, we separated climatic effects from local conditions. At the arid sowing location, two species supported the prediction of low germination of drier seed origins, but differences between seed origins at the other sites were not substantial. There were no clear rainfall effects on germination. Germination fractions were consistently lower on local soil than on standard soil, indicating the important role of soil type and neighbour conditions for trait expression. Local environmental conditions may override effects of climate and so should be carefully addressed in future studies testing for the potential of species to adapt or plastically respond to climate change.

bZIP17 regulates the expression of genes related to seed storage and germination, reducing seed susceptibility to osmotic stress.

PubMed

Cifuentes-Esquivel, Nicolás; Celiz-Balboa, Jonathan; Henriquez-Valencia, Carlos; Mitina, Irina; Arraño-Salinas, Paulina; Moreno, Adrián A; Meneses, Claudio; Blanco-Herrera, Francisca; Orellana, Ariel

2018-04-25

Low temperatures, salinity, and drought cause significant crop losses. These conditions involve osmotic stress, triggering transcriptional remodeling, and consequently, the restitution of cellular homeostasis and growth recovery. Protein transcription factors regulate target genes, thereby mediating plant responses to stress. bZIP17 is a transcription factor involved in cellular responses to salinity and the unfolded protein response. Because salinity can also produce osmotic stress, the role of bZIP17 in response to osmotic stress was assessed. Mannitol treatments induced the transcript accumulation and protein processing of bZIP17. Transcriptomic analyses showed that several genes associated with seed storage and germination showed lower expression in bzip17 mutants than in wild-type plants. Interestingly, bZIP17 transcript was more abundant in seeds, and germination analyses revealed that wild-type plants germinated later than bzip17 mutants in the presence of mannitol, but no effects were observed when the seeds were exposed to ABA. Finally, the transcript levels of bZIP17 target genes that control seed storage and germination were assessed in seeds exposed to mannitol treatments, which showed lower expression levels in bzip17 mutants compared to the wild-type seeds. These results suggest that bZIP17 plays a role in osmotic stress, acting as a negative regulator of germination through the regulation of genes involved in seed storage and germination. © 2018 Wiley Periodicals, Inc.

Comparative proteomic analysis of alfalfa revealed new salt and drought stress-related factors involved in seed germination.

PubMed

Ma, Qiaoli; Kang, Junmei; Long, Ruicai; Zhang, Tiejun; Xiong, Junbo; Zhang, Kun; Wang, Tenghua; Yang, Qingchuan; Sun, Yan

2017-07-01

Salinity and drought are two major environmental factors that limit the growth and yield of many forage crops in semi-arid and arid regions. Alfalfa (Medicago sativa L.) is one of the most important forage crops in many countries. We aim to investigate the molecular mechanisms of alfalfa in response to salt and drought stresses in this study. Physiological and proteomic analyses were applied to examine the Zhongmu NO.3 alfalfa seed germination stage with 200 mM NaCl and 180 g·L -1 polyethylene glycol (PEG) treatments. The germination ability of the seed and the accumulation of osmotic solutes were quite different between the NaCl and PEG treatments. More than 800 protein spots were detected by proteomics technology on two-dimensional electrophoresis (2-DE) gels. The abundance of twenty-eight proteins were decreased or increased after salt and drought stress. Seventeen of these proteins were identified and classified into six functional categories through mass spectrometry (MS). The six groups involved in salt- and PEG-mediated stress included defense response, energy metabolism, protein synthesis and degradation, oxidative stress, carbohydrate metabolism-associated proteins, and unknown proteins. We discovered that some proteins related to carbohydrate metabolism and energy production increased in abundance under salt- and PEG-mediated drought stress. This demonstrates a common mechanism of energy consumption during abiotic stresses. Further study of these proteins with unknown function will provide insights into the molecular mechanisms of abiotic stress and the discovery of new candidate markers.

Protein Solubility, Digestibility and Fractionation after Germination of Sorghum Varieties

PubMed Central

Afify, Abd El-Moneim M. R.; El-Beltagi, Hossam S.; Abd El-Salam, Samiha M.; Omran, Azza A.

2012-01-01

The changes in crude protein, free amino acids, amino acid composition, protein solubility, protein fractionation and protein digestibility after germination of sorghum were investigated. Sorghum varieties (Dorado, Shandaweel-6, Giza-15) were soaked for 20 h followed by germination for 72 h; the results revealed that crude protein and free amino acids in raw sorghum varieties ranged from 10.62 to 12.46% and 0.66 to 1.03 mg/g, respectively. Shandaweel-6 was the highest variety in crude protein and free amino acids content. After germination, crude protein was decreased and free amino acids were increased. There was an increase in content of valine and phenylalanine amino acids after germination. On the other hand, there was a decrease in most of amino acids after germination. After germination protein solubility was significantly increased. Regarding protein fractions, there was an increase in albumin, globulin and kafirin proteins and a decrease in cross linked kafirin and cross linked glutelin after germination. PMID:22319611

Germination and soil seed bank traits of Podocarpus angustifolius (Podocarpaceae): an endemic tree species from Cuban rain forests.

PubMed

Ferrandis, Pablo; Bonilla, Marta; Osorio, Licet del Carmen

2011-09-01

Podocarpus angustifolius is an endangered recalcitrant-seeded small tree, endemic to mountain rain forests in the central and Pinar del Río regions in Cuba. In this study, the germination patterns of P. angustifolius seeds were evaluated and the nature of the soil seed bank was determined. Using a weighted two-factor design, we analyzed the combined germination response to seed source (i.e. freshly matured seeds directly collected from trees versus seeds extracted from soil samples) and pretreatment (i.e. seed water-immersion for 48h at room temperature). Germination was delayed for four weeks (= 30 days) in all cases, regardless of both factors analyzed. Moreover, nine additional days were necessary to achieve high germination values (in the case of fresh, pretreated seeds). These results overall may indicate the existence of a non-deep simple morphophysiological dormancy in P. angustifolius seeds. The water-immersion significantly enhanced seed germination, probably as a result of the hydration of recalcitrant seeds. Although germination of seeds extracted from soil samples was low, probably due to aging and pathogen effects throughout the time of burial, the study revealed the existence of a persistent soil seed bank (at least short-termed) of approximately 42 viable seeds per m2 in the upper 10cm of soil. Such a record is noteworthy since references to persistent soil seed banks in recalcitrant-seeded species are scarce in the literature. The population consequences derived from the formation of persistent soil seed banks in this endangered species are discussed.

The NF-YC–RGL2 module integrates GA and ABA signalling to regulate seed germination in Arabidopsis

PubMed Central

Liu, Xu; Hu, Pengwei; Huang, Mingkun; Tang, Yang; Li, Yuge; Li, Ling; Hou, Xingliang

2016-01-01

The antagonistic crosstalk between gibberellic acid (GA) and abscisic acid (ABA) plays a pivotal role in the modulation of seed germination. However, the molecular mechanism of such phytohormone interaction remains largely elusive. Here we show that three Arabidopsis NUCLEAR FACTOR-Y C (NF-YC) homologues NF-YC3, NF-YC4 and NF-YC9 redundantly modulate GA- and ABA-mediated seed germination. These NF-YCs interact with the DELLA protein RGL2, a key repressor of GA signalling. The NF-YC–RGL2 module targets ABI5, a gene encoding a core component of ABA signalling, via specific CCAAT elements and collectively regulates a set of GA- and ABA-responsive genes, thus controlling germination. These results suggest that the NF-YC–RGL2–ABI5 module integrates GA and ABA signalling pathways during seed germination. PMID:27624486

Modelling the effect of water activity reduction by sodium chloride or glycerol on conidial germination and radial growth of filamentous fungi encountered in dairy foods.

PubMed

Nguyen Van Long, Nicolas; Rigalma, Karim; Coroller, Louis; Dadure, Robin; Debaets, Stella; Mounier, Jérôme; Vasseur, Valérie

2017-12-01

Water activity (a w ) is one of the most influential abiotic factors affecting fungal development in foods. The effects of a w reduction on conidial germination and radial growth are generally studied by supplementing culture medium with the non-ionic solute glycerol despite food a w can also depend on the concentration of ionic solutes such as sodium chloride (NaCl). The present study aimed at modelling and comparing the effects of a w , either modified using NaCl or glycerol, on radial growth and/or conidial germination parameters for five fungal species occurring in the dairy environment. The estimated cardinal values were then used for growth prediction and compared to growth kinetics observed on commercial fresh cheese. Overall, as compared to glycerol, NaCl significantly increased the fungistatic effect resulting from a w reduction by extending latency and/or reducing radial growth rates of Paecilomyces niveus, Penicillium brevicompactum, Penicillium expansum and Penicillium roqueforti but not of Mucor lanceolatus. Besides, NaCl significantly reduced a w range for conidial germination and delayed median germination time of P. expansum but not of P. roqueforti. Despite these observations, cardinal a w values obtained on glycerol-medium yielded similar predictions of radial growth and germination time in commercial fresh cheese as those obtained with NaCl. Thus, it indicates that, for the studied species and a w range used for model validation, the use of NaCl instead of glycerol as a a w depressor had only limited impact for fungal behavior prediction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Raffinose and stachyose metabolism are not required for efficient soybean seed germination.

PubMed

Dierking, Emily C; Bilyeu, Kristin D

2009-08-15

Raffinose family oligosaccharides (RFOs), which include raffinose and stachyose, are thought to be an important source of energy during seed germination. In contrast to their potential for promoting germination, RFOs represent anti-nutritional units for monogastric animals when consumed as a component of feed. The exact role for RFOs during soybean seed development and germination has not been experimentally determined; but it has been hypothesized that RFOs are required for successful germination. Previously, inhibition of RFO breakdown during imbibition and germination was shown to significantly delay germination in pea seeds. The objective of this study was to compare the germination potential for soybean seeds with either wild-type (WT) or low RFO levels and to examine the role of RFO breakdown in germination of soybean seeds. There was no significant difference in germination between normal and low RFO soybean seeds when imbibed/germinated in water. Similar to the situation in pea, soybean seeds of wild-type carbohydrate composition experienced a delay in germination when treated with a chemical inhibitor of alpha-galactosidase activity (1-deoxygalactonojirimycin or DGJ) during imbibition. However, low RFO soybean seed germination was not significantly delayed or reduced when treated with DGJ. In contrast to the situation in pea, the inhibitor-induced germination delay in wild-type soybean seeds was not partially overcome by the addition of galactose or sucrose. We conclude that RFOs are not an essential source of energy during soybean seed germination.

Germination responses of the invasive Calotropis procera (Ait.) R. Br. (Apocynaceae): comparisons with seeds from two ecosystems in Northeastern Brazil.

PubMed

Leal, Laura C; Meiado, Marcos V; Lopes, Ariadna V; Leal, Inara R

2013-09-01

Life history traits are considered key indicators of plant invasibility. Among them, the germination behavior of seeds is of major relevance because it is influenced by environmental factors of invaded ecosystem. Here, we investigated how seed traits and seed tolerance to environmental factors on seed germination of Calotropis procera vary depending on the invaded ecosystems in northeastern Brazil. We have tested seeds from two vegetation types - Caatinga and Restinga - to different levels of light intensity, salinity, and water stress. Previous to those experiments, seed-set and morphometric analysis were carried out for both studied populations. We have observed a higher seed-set in Caatinga. Seeds produced in this ecosystem had lower seed moisture content. Seeds from Restinga showed lower germination time when light intensity decreased. We observed a reduction in both the germinability and the synchronization index with decreasing osmotic potential and increasing salinity. Nevertheless, both populations exhibited changes in photoblastism when seeds were submitted to water and saline stress. In conclusion, C. procera seeds are tolerant to environmental factors assessed. That characteristic ensures the colonization success and wide distribution of this plant species in the studied ecosystems.

Proteomic investigation of the effect of salicylic acid on Arabidopsis seed germination and establishment of early defense mechanisms.

PubMed

Rajjou, Loïc; Belghazi, Maya; Huguet, Romain; Robin, Caroline; Moreau, Adrien; Job, Claudette; Job, Dominique

2006-07-01

The influence of salicylic acid (SA) on elicitation of defense mechanisms in Arabidopsis (Arabidopsis thaliana) seeds and seedlings was assessed by physiological measurements combined with global expression profiling (proteomics). Parallel experiments were carried out using the NahG transgenic plants expressing the bacterial gene encoding SA hydroxylase, which cannot accumulate the active form of this plant defense elicitor. SA markedly improved germination under salt stress. Proteomic analyses disclosed a specific accumulation of protein spots regulated by SA as inferred by silver-nitrate staining of two-dimensional gels, detection of carbonylated (oxidized) proteins, and neosynthesized proteins with [35S]-methionine. The combined results revealed several processes potentially affected by SA. This molecule enhanced the reinduction of the late maturation program during early stages of germination, thereby allowing the germinating seeds to reinforce their capacity to mount adaptive responses in environmental water stress. Other processes affected by SA concerned the quality of protein translation, the priming of seed metabolism, the synthesis of antioxidant enzymes, and the mobilization of seed storage proteins. All the observed effects are likely to improve seed vigor. Another aspect revealed by this study concerned the oxidative stress entailed by SA in germinating seeds, as inferred from a characterization of the carbonylated (oxidized) proteome. Finally, the proteomic data revealed a close interplay between abscisic signaling and SA elicitation of seed vigor.

Effect of fungicides on Wyoming big sagebrush seed germination

Treesearch

Robert D. Cox; Lance H. Kosberg; Nancy L. Shaw; Stuart P. Hardegree

2011-01-01

Germination tests of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young [Asteraceae]) seeds often exhibit fungal contamination, but the use of fungicides should be avoided because fungicides may artificially inhibit germination. We tested the effect of seed-applied fungicides on germination of Wyoming big sagebrush at 2 different...

KELCH F-BOX protein positively influences Arabidopsis seed germination by targeting PHYTOCHROME-INTERACTING FACTOR1

USDA-ARS?s Scientific Manuscript database

Seeds employ sensory systems that assess various environmental cues over time to maximize the successful transition from embryo to seedling. Here, we show that the Arabidopsis F-Box protein Cold Temperature-Germinating (CTG)-10, identified by activation tagging, is a positive regulator during this p...

A high-throughput seed germination assay for root parasitic plants

PubMed Central

2013-01-01

Background Some root-parasitic plants belonging to the Orobanche, Phelipanche or Striga genus represent one of the most destructive and intractable weed problems to agricultural production in both developed and developing countries. Compared with most of the other weeds, parasitic weeds are difficult to control by conventional methods because of their life style. The main difficulties that currently limit the development of successful control methods are the ability of the parasite to produce a tremendous number of tiny seeds that may remain viable in the soil for more than 15 years. Seed germination requires induction by stimulants present in root exudates of host plants. Researches performed on these minute seeds are until now tedious and time-consuming because germination rate is usually evaluated in Petri-dish by counting germinated seeds under a binocular microscope. Results We developed an easy and fast method for germination rate determination based on a standardized 96-well plate test coupled with spectrophotometric reading of tetrazolium salt (MTT) reduction. We adapted the Mosmann’s protocol for cell cultures to germinating seeds and determined the conditions of seed stimulation and germination, MTT staining and formazan salt solubilization required to obtain a linear relationship between absorbance and germination rate. Dose–response analyses were presented as applications of interest for assessing half maximal effective or inhibitory concentrations of germination stimulants (strigolactones) or inhibitors (ABA), respectively, using four parameter logistic curves. Conclusion The developed MTT system is simple and accurate. It yields reproducible results for germination bioassays of parasitic plant seeds. This method is adapted to high-throughput screenings of allelochemicals (stimulants, inhibitors) or biological extracts on parasitic plant seed germination, and strengthens the investigations of distinctive features of parasitic plant germination

Genetic variation in salt tolerance during seed germination in a backcross inbred line population and advanced breeding lines derived from upland cotton x pima cotton

USDA-ARS?s Scientific Manuscript database

Seed germination is a crucial phase of the plant life cycle that affects its establishment and productivity. However, information on salt tolerance at this phase is limited. Pima cotton (Gossypium barbadense L.) may be more salt tolerant during germination than Upland cotton (G. hirsutum L.) based o...

Efficient production of human acidic fibroblast growth factor in pea (Pisum sativum L.) plants by agroinfection of germinated seeds

PubMed Central

2011-01-01

Background For efficient and large scale production of recombinant proteins in plants transient expression by agroinfection has a number of advantages over stable transformation. Simple manipulation, rapid analysis and high expression efficiency are possible. In pea, Pisum sativum, a Virus Induced Gene Silencing System using the pea early browning virus has been converted into an efficient agroinfection system by converting the two RNA genomes of the virus into binary expression vectors for Agrobacterium transformation. Results By vacuum infiltration (0.08 Mpa, 1 min) of germinating pea seeds with 2-3 cm roots with Agrobacteria carrying the binary vectors, expression of the gene for Green Fluorescent Protein as marker and the gene for the human acidic fibroblast growth factor (aFGF) was obtained in 80% of the infiltrated developing seedlings. Maximal production of the recombinant proteins was achieved 12-15 days after infiltration. Conclusions Compared to the leaf injection method vacuum infiltration of germinated seeds is highly efficient allowing large scale production of plants transiently expressing recombinant proteins. The production cycle of plants for harvesting the recombinant protein was shortened from 30 days for leaf injection to 15 days by applying vacuum infiltration. The synthesized aFGF was purified by heparin-affinity chromatography and its mitogenic activity on NIH 3T3 cells confirmed to be similar to a commercial product. PMID:21548923

AtMyb7, a subgroup 4 R2R3 Myb, negatively regulates ABA-induced inhibition of seed germination by blocking the expression of the bZIP transcription factor ABI5.

PubMed

Kim, Jun Hyeok; Hyun, Woo Young; Nguyen, Hoai Nguyen; Jeong, Chan Young; Xiong, Liming; Hong, Suk-Whan; Lee, Hojoung

2015-03-01

Various Myb proteins have been shown to play crucial roles in plants, including primary and secondary metabolism, determination of cell fate and identity, regulation of development and involvement in responses to biotic and abiotic stresses. The 126 R2R3 Myb proteins (with two Myb repeats) have been found in Arabidopsis; however, the functions of most of these proteins remain to be fully elucidated. In the present study, we characterized the function of AtMyb7 using molecular biological and genetic analyses. We used qRT-PCR to determine the levels of stress-response gene transcripts in wild-type and atmyb7 plants. We showed that Arabidopsis AtMyb7 plays a critical role in seed germination. Under abscisic acid (ABA) and high-salt stress conditions, atmyb7 plants showed a lower germination rate than did wild-type plants. Furthermore, AtMyb7 promoter:GUS seeds exhibited different expression patterns in response to variations in the seed imbibition period. AtMyb7 negatively controls the expression of the gene encoding bZIP transcription factor, ABI5, which is a key transcription factor in ABA signalling and serves as a crucial regulator of germination inhibition in Arabidopsis. © 2014 John Wiley & Sons Ltd.

Factors Affecting Tocopherol Concentrations in Soybean Seeds.

PubMed

Carrera, Constanza S; Seguin, Philippe

2016-12-21

Soybean seeds contain several health-beneficial compounds, including tocopherols, which are used by the nutraceutical and functional food industries. Soybean tocopherol concentrations are, however, highly variable. Large differences observed in tocopherol concentrations among soybean genotypes together with the relatively simple biosynthetic pathway involving few genes support the feasibility of selecting for high-tocopherol soybean. Tocopherol concentrations are also highly influenced by environmental factors and field management. Temperature during seed filling and soil moisture appear to be the main factors affecting tocopherol concentrations; other factors such as soil fertility and solar radiation also affect concentrations and composition. Field management decisions including seeding date, row spacing, irrigation, and fertilization also affect tocopherols. Knowledge of factors affecting soybean tocopherols is essential to develop management strategies that will lead to the production of seeds with consistent target concentrations that will meet the needs of the nutraceutical and functional food industries.

Germinated wheat: Phytochemical composition and mixing characteristics

USDA-ARS?s Scientific Manuscript database

Germinated grain recently attracts interest due to its beneficial effect on human health. In this research, whole wheat flour samples obtained after three days and five days of germination were analyzed for biochemical components, mixing quality, and effects on human breast cancer cells. Germinati...

Superoxide and its metabolism during germination and axis growth of Vigna radiata (L.) Wilczek seeds

PubMed Central

Singh, Khangembam Lenin; Chaudhuri, Abira; Kar, Rup Kumar

2014-01-01

Involvement of reactive oxygen species in regulation of plant growth and development is recently being demonstrated with various results depending on the experimental system and plant species. Role of superoxide and its metabolism in germination and axis growth was investigated in case of Vigna radiata seeds, a non-endospermous leguminous species having epigeal germination, by studying the effect of different reactive oxygen species (ROS) inhibitors, distribution of O2•ˉ and H2O2 and ROS enzyme profile in axes. Germination percentage and axis growth were determined under treatment with ROS inhibitors and scavengers. Localization of O2•ˉ and H2O2 was done using nitroblue tetrazolium (NBT) and 3,3′,5,5′-tetramethyl benzidine dihydrochloride hydrate (TMB), respectively. Apoplastic level of O2•ˉ was monitored by spectrophotometric analysis of bathing medium of axes. Profiles of NADPH oxidase and superoxide dismutase (SOD) were studied by in-gel assay. Germination was retarded by treatments affecting ROS level except H2O2 scavengers, while axis growth was retarded by all. Superoxide synthesis inhibitor and scavenger prevented H2O2 accumulation in axes in later phase as revealed from TMB staining. Activity of Cu/Zn SOD1 was initially high and declined thereafter. Superoxide being produced in apoplast possibly by NADPH oxidase activity is further metabolized to •OH via H2O2. Germination process depends possibly on •OH production in the axes. Post-germinative axis growth requires O2•ˉ while the differentiating zone of axis (radicle) requires H2O2 for cell wall stiffening. PMID:25763616

Response of insects to damaged and undamaged germinating acorns

Treesearch

Jimmy R. Galford; Deloris Weiss-Cottrill

1991-01-01

Damaged germinating northern red oak, Quercus rubra L., acorns in pitfall traps were significantly more attractive to two species of acorn insects than undamaged germinating acorns. Significantly more adults of the weevil Conotrachelus posticatus ohe em an and the sap beetle Stelidota octomaculata (Say) were caught in traps containing germinating acorns cut into halves...

Web-based Factors Affecting Online Purchasing Behaviour

NASA Astrophysics Data System (ADS)

Ariff, Mohd Shoki Md; Sze Yan, Ng; Zakuan, Norhayati; Zaidi Bahari, Ahamad; Jusoh, Ahmad

2013-06-01

The growing use of internet and online purchasing among young consumers in Malaysia provides a huge prospect in e-commerce market, specifically for B2C segment. In this market, if E-marketers know the web-based factors affecting online buyers' behaviour, and the effect of these factors on behaviour of online consumers, then they can develop their marketing strategies to convert potential customers into active one, while retaining existing online customers. Review of previous studies related to the online purchasing behaviour in B2C market has point out that the conceptualization and empirical validation of the online purchasing behaviour of Information and Communication Technology (ICT) literate users, or ICT professional, in Malaysia has not been clearly addressed. This paper focuses on (i) web-based factors which online buyers (ICT professional) keep in mind while shopping online; and (ii) the effect of web-based factors on online purchasing behaviour. Based on the extensive literature review, a conceptual framework of 24 items of five factors was constructed to determine web-based factors affecting online purchasing behaviour of ICT professional. Analysis of data was performed based on the 310 questionnaires, which were collected using a stratified random sampling method, from ICT undergraduate students in a public university in Malaysia. The Exploratory factor analysis performed showed that five factors affecting online purchase behaviour are Information Quality, Fulfilment/Reliability/Customer Service, Website Design, Quick and Details, and Privacy/Security. The result of Multiple Regression Analysis indicated that Information Quality, Quick and Details, and Privacy/Security affect positively online purchase behaviour. The results provide a usable model for measuring web-based factors affecting buyers' online purchase behaviour in B2C market, as well as for online shopping companies to focus on the factors that will increase customers' online purchase.

Decrease in optical density as a results of germination of Alicyclobacillus acidoterrestris spores under high hydrostatic pressure

NASA Astrophysics Data System (ADS)

Porębska, I.; Rutkowska, M.; Sokołowska, B.

2015-01-01

Alicyclobacillus acidoterrestris is a spore-forming bacterium, causing spoilage of juices. The spores of these bacteria have the ability to survive in the typical conditions used for thermal pasteurization. Therefore, the use of other techniques such as high hydrostatic pressure is considered for their inactivation. The effect of hydrostatic pressure of 200-500 MPa, at temperatures 4-50 °C for 15 min, on the dynamics of germination of A. acidoterrestris spores in apple juice and pH 4 buffer was studied. To estimate the share of germinated spores, the method of determining the optical density at a wavelength of 660 nm (OD660) was used. Parameters of hydrostatic pressure treatment used in this work affected the dynamics of germination of A. acidoterrestris spores in apple juice, and the temperature had the greatest effect. The results indicate that nutrients present in apple juice can promote the germination of A. acidoterrestris spores. This paper was presented at the 8th International Conference on High Pressure Bioscience & Biotechnology (HPBB 2014) in Nantes (France) 15-18 July 2014.

Temperature regulates positively photoblastic seed germination in four ficus (moraceae) tree species from contrasting habitats in a seasonal tropical rainforest.

PubMed

Chen, Hui; Cao, Min; Baskin, Jerry M; Baskin, Carol C

2013-08-01

Differences in seed germination responses of trees in tropical forests to temperature and light quality may contribute to their coexistence. We investigated the effects of temperature and red:far-red light (R:FR ratio) on seed germination of two gap-demanding species (Ficus hispida and F. racemosa) and two shade-tolerant species (F. altissima and F. auriculata) in a tropical seasonal rainforest in southwest China. A R:FR ratio gradient was created by filtering fluorescent light through polyester filters. Four temperature treatments were used to test the effect of temperature on seed germination of the four Ficus tree species across the R:FR gradient. Seeds of the four Ficus species were positively photoblastic. Seed germination of F. hispida and F. racemosa was not affected across the R:FR ratio gradient (0.25-1.19) at 25/35°C, but it was inhibited under low R:FR at 22/23°C. By contrast, germination percentages of F. altissima and F. auriculata were not inhibited along the entire light gradient in all temperature treatments. Differences in germination responses of Ficus species might contribute to differences in their habitat preferences. The inhibitory effect of understory temperatures in the forest might be a new mechanism that prevents positively photoblastic seeds of the gap-demanding species such as F. hispida and F. racemosa from germinating in the understory and in small canopy gaps.

Strigolactones as germination stimulants for root parasitic plants.

PubMed

Yoneyama, Koichi; Awad, Ayman A; Xie, Xiaonan; Yoneyama, Kaori; Takeuchi, Yasutomo

2010-07-01

Witchweeds (Striga spp.) and broomrapes (Orobanche and Phelipanche spp.) are the two most devastating root parasitic plants belonging to the family Orobanchaceae and are causing enormous crop losses throughout the world. Seeds of these root parasites will not germinate unless they are exposed to chemical stimuli, 'germination stimulants' produced by and released from plant roots. Most of the germination stimulants identified so far are strigolactones (SLs), which also function as host recognition signals for arbuscular mycorrhizal fungi and a novel class of plant hormones inhibiting shoot branching. In this review, we focus on SLs as germination stimulants for root parasitic plants. In addition, we discuss how quantitative and qualitative differences in SL exudation among sorghum cultivars influence their susceptibility to Striga.

Seed and Germination Characteristics of 20 Amazonian Liana Species

PubMed Central

Roeder, Mareike; Ferraz, Isolde D. K.; Hölscher, Dirk

2013-01-01

Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark) and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C) was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g) and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches. PMID:27137363

Evaluation of the effect of germination on phenolic compounds and antioxidant activities in sorghum varieties.

PubMed

Dicko, Mamoudou H; Gruppen, Harry; Traore, Alfred S; van Berkel, Willem J H; Voragen, Alphons G J

2005-04-06

The screening of 50 sorghum varieties showed that, on average, germination did not affect the content in total phenolic compounds but decreased the content of proanthocyanidins, 3-deoxyanthocyanidins, and flavan-4-ols. Independent of germination, there are intervarietal differences in antioxidant activities among sorghum varieties. Phenolic compounds and antioxidant activities were more positively correlated in ungerminated varieties than in germinated ones. Sorghum grains with pigmented testa layer, chestnut color glumes, and red plants had higher contents, larger diversity of phenolic compounds, and higher antioxidant activities than other sorghums. Some red sorghum varieties had higher antioxidant activities (30-80 mumol of Trolox equiv/g) than several sources of natural antioxidants from plant foods. Among varieties used for "to", "dolo", couscous, and porridge preparation, the "dolo"(local beer) varieties had the highest average content and diversity in phenolic compounds as well as the highest antioxidant activities. The biochemical markers determined are useful indicators for the selection of sorghum varieties for food and agronomic properties.

Effects of reduced winter duration on seed dormancy and germination in six populations of the alpine herb Aciphyllya glacialis (Apiaceae)

PubMed Central

Hoyle, G. L.; Cordiner, H.; Good, R. B.; Nicotra, A. B.

2014-01-01

The life stages of seed germination and seedling establishment play a vital role in maintaining plant populations and determining range dynamics of species. Thus, it is not surprising that specific germination requirements and dormancy mechanisms have evolved in all major angiosperm clades. In a rapidly changing climate, we face growing pressure to manage, conserve and restore native plant species and communities. To achieve these aims, we require solid knowledge of whether and how seed germination requirements and dormancy status vary between different populations of a given species and how germination strategies may be affected by warming climatic conditions. We assessed the effect of decreasing durations of cold stratification (i.e. conditions representing a shortened winter as predicted under climate change) on germination and dormancy of the alpine herb Aciphylla glacialis. Our results confirmed previous research showing that A. glacialis seeds possess physiological dormancy that can be alleviated by cold stratification. In addition, the results demonstrated that A. glacialis seeds have underdeveloped embryos at dispersal; these grow to germinable size following 4–9 weeks at both constant 5°C and 10–5°C (day–night) temperatures. We conclude that A. glacialis exhibits morphophysiological dormancy. Furthermore, we found that the final percentage germination and dormancy status varied significantly among natural populations and that this variation did not correlate with elevation at the site of seed origin. Seeds germinated following 6–8 weeks of cold stratification, and seedlings showed no detrimental effects as a result of shorter stratification periods. Together, these results suggest that reduced duration of winter is unlikely to have direct negative impacts on germination or early seedling growth in A. glacialis. The causes and implications of the population variation in germination traits are discussed. PMID:27293636

The effects of soak temperature on sugar maple seed germination

Treesearch

Carol A. Janerette

1978-01-01

The temperature at which sugar maple seeds were soaked before stratification significantly influenced their germination. Maximal germination was obtained when seeds were soaked at 4?C, but if seeds were soaked at 25?C, germination decreased and the stratification requirement increased.

Interleukin 6 Influences Germinal Center Development and Antibody Production via a Contribution of C3 Complement Component

PubMed Central

Kopf, Manfred; Herren, Suzanne; Wiles, Michael V.; Pepys, Mark B.; Kosco-Vilbois, Marie H.

1998-01-01

Mice rendered deficient for interleukin (IL) 6 by gene targeting were evaluated for their response to T cell–dependent antigens. Antigen-specific immunoglobulin (Ig)M levels were unaffected whereas all IgG isotypes showed varying degrees of alteration. Germinal center reactions occurred but remained physically smaller in comparison to those in the wild-type mice. This concurred with the observations that molecules involved in initial signaling events leading to germinal center formation were not altered (e.g., B7.2, CD40 and tumor necrosis factor R1). T cell priming was not impaired nor was a gross imbalance of T helper cell (Th) 1 versus Th2 cytokines observed. However, B7.1 molecules, absent from wild-type counterparts, were detected on germinal center B cells isolated from the deficient mice suggesting a modification of costimulatory signaling. A second alteration involved impaired de novo synthesis of C3 both in serum and germinal center cells from IL-6–deficient mice. Indeed, C3 provided an essential stimulatory signal for wild-type germinal center cells as both monoclonal antibodies that interrupted C3-CD21 interactions and sheep anti–mouse C3 antibodies caused a significant decrease in antigen-specific antibody production. In addition, germinal center cells isolated from C3–deficient mice produced a similar defect in isotype production. Low density cells with dendritic morphology were the local source of IL-6 and not the germinal center lymphocytes. Adding IL-6 in vitro to IL-6–deficient germinal center cells stimulated cell cycle progression and increased levels of antibody production. These findings reveal that the germinal center produces and uses molecules of the innate immune system, evolutionarily pirating them in order to optimally generate high affinity antibody responses. PMID:9815267

Intestinal calcium and bile salts facilitate germination of Clostridium difficile spores

PubMed Central

Kochan, Travis J.; Kaiser, Alyssa M.; Hastie, Jessica L.; Giordano, Nicole P.; Smith, Ashley D.

2017-01-01

Clostridium difficile (C. difficile) is an anaerobic gram-positive pathogen that is the leading cause of nosocomial bacterial infection globally. C. difficile infection (CDI) typically occurs after ingestion of infectious spores by a patient that has been treated with broad-spectrum antibiotics. While CDI is a toxin-mediated disease, transmission and pathogenesis are dependent on the ability to produce viable spores. These spores must become metabolically active (germinate) in order to cause disease. C. difficile spore germination occurs when spores encounter bile salts and other co-germinants within the small intestine, however, the germination signaling cascade is unclear. Here we describe a signaling role for Ca2+ during C. difficile spore germination and provide direct evidence that intestinal Ca2+ coordinates with bile salts to stimulate germination. Endogenous Ca2+ (released from within the spore) and a putative AAA+ ATPase, encoded by Cd630_32980, are both essential for taurocholate-glycine induced germination in the absence of exogenous Ca2+. However, environmental Ca2+ replaces glycine as a co-germinant and circumvents the need for endogenous Ca2+ fluxes. Cd630_32980 is dispensable for colonization in a murine model of C. difficile infection and ex vivo germination in mouse ileal contents. Calcium-depletion of the ileal contents prevented mutant spore germination and reduced WT spore germination by 90%, indicating that Ca2+ present within the gastrointestinal tract plays a critical role in C. difficile germination, colonization, and pathogenesis. These data provide a biological mechanism that may explain why individuals with inefficient intestinal calcium absorption (e.g., vitamin D deficiency, proton pump inhibitor use) are more prone to CDI and suggest that modulating free intestinal calcium is a potential strategy to curb the incidence of CDI. PMID:28704538

New insights into the roles of NADPH oxidases in sexual development and ascospore germination in Sordaria macrospora.

PubMed

Dirschnabel, Daniela Elisabeth; Nowrousian, Minou; Cano-Domínguez, Nallely; Aguirre, Jesus; Teichert, Ines; Kück, Ulrich

2014-03-01

NADPH oxidase (NOX)-derived reactive oxygen species (ROS) act as signaling determinants that induce different cellular processes. To characterize NOX function during fungal development, we utilized the genetically tractable ascomycete Sordaria macrospora. Genome sequencing of a sterile mutant led us to identify the NADPH oxidase encoding nox1 as a gene required for fruiting body formation, regular hyphal growth, and hyphal fusion. These phenotypes are shared by nor1, lacking the NOX regulator NOR1. Further phenotypic analyses revealed a high correlation between increased ROS production and hyphal fusion deficiencies in nox1 and other sterile mutants. A genome-wide transcriptional profiling analysis of mycelia and isolated protoperithecia from wild type and nox1 revealed that nox1 inactivation affects the expression of genes related to cytoskeleton remodeling, hyphal fusion, metabolism, and mitochondrial respiration. Genetic analysis of nox2, lacking the NADPH oxidase 2 gene, nor1, and transcription factor deletion mutant ste12, revealed a strict melanin-dependent ascospore germination defect, indicating a common genetic pathway for these three genes. We report that gsa3, encoding a G-protein α-subunit, and sac1, encoding cAMP-generating adenylate cyclase, act in a separate pathway during the germination process. The finding that cAMP inhibits ascospore germination in a melanin-dependent manner supports a model in which cAMP inhibits NOX2 activity, thus suggesting a link between both pathways. Our results expand the current knowledge on the role of NOX enzymes in fungal development and provide a frame to define upstream and downstream components of the NOX signaling pathways in fungi.

Isolation of tissues and preservation of RNA from intact, germinated barley grain.

PubMed

Betts, Natalie S; Berkowitz, Oliver; Liu, Ruijie; Collins, Helen M; Skadhauge, Birgitte; Dockter, Christoph; Burton, Rachel A; Whelan, James; Fincher, Geoffrey B

2017-08-01

Isolated barley (Hordeum vulgare L.) aleurone layers have been widely used as a model system for studying gene expression and hormonal regulation in germinating cereal grains. A serious technological limitation of this approach has been the inability to confidently extrapolate conclusions obtained from isolated tissues back to the whole grain, where the co-location of several living and non-living tissues results in complex tissue-tissue interactions and regulatory pathways coordinated across the multiple tissues. Here we have developed methods for isolating fragments of aleurone, starchy endosperm, embryo, scutellum, pericarp-testa, husk and crushed cell layers from germinated grain. An important step in the procedure involves the rapid fixation of the intact grain to freeze the transcriptional activity of individual tissues while dissection is effected for subsequent transcriptomic analyses. The developmental profiles of 19 611 gene transcripts were precisely defined in the purified tissues and in whole grain during the first 24 h of germination by RNA sequencing. Spatial and temporal patterns of transcription were validated against well-defined data on enzyme activities in both whole grain and isolated tissues. Transcript profiles of genes involved in mitochondrial assembly and function were used to validate the very early stages of germination, while the profiles of genes involved in starch and cell wall mobilisation matched existing data on activities of corresponding enzymes. The data will be broadly applicable for the interrogation of co-expression and differential expression patterns and for the identification of transcription factors that are important in the early stages of grain and seed germination. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Campanulaceae: a family with small seeds that require light for germination

PubMed Central

Koutsovoulou, Katerina; Daws, Matthew I.; Thanos, Costas A.

2014-01-01

Background and Aims The Campanulaceae is a large cosmopolitan family, but is understudied in terms of germination, and seed biology in general. Small seed mass (usually in the range 10–200 µg) is a noteworthy trait of the family, and having small seeds is commonly associated with a light requirement. Thus, the purpose of this study was to investigate the effect of light on germination in 131 taxa of the Campanulaceae family, from all five continents of its distribution. Methods For all taxa, seed germination was tested in light (8 or 12 h photoperiod) and continuous darkness under constant and alternating temperatures. For four taxa, the effect of light on germination was examined over a wide range of temperatures on a thermogradient plate, and the possible substitution of the light requirement by gibberellic acid and nitrate was examined in ten taxa. Key Results For all 131 taxa, seed germination was higher in light than in darkness for every temperature tested. Across species, the light requirement decreased significantly with increasing seed mass. For larger seeded species, germination in the dark reached higher levels under alternating than under constant temperatures. Gibberellic acid promoted germination in darkness whereas nitrates partially substituted for a light requirement only in species showing some dark germination. Conclusions A light requirement for germination, observed in virtually all taxa examined, constitutes a collective characteristic of the family. It is postulated that smaller seeded taxa might germinate only on the soil surface or at shallow depths, while larger seeded species might additionally germinate when buried in the soil if cued to do so by fluctuating temperatures. PMID:24232382

Impact of dyeing industry effluent on germination and growth of pea (Pisum sativum).

PubMed

Malaviya, Piyush; Hali, Rajesh; Sharma, Neeru

2012-11-01

Dye industry effluent was analyzed for physico-chemical characteristics and its impact on germination and growth behaviour of Pea (Pisum sativum). The 100% effluent showed high pH (10.3) and TDS (1088 mg l(-1)). The germination parameters included percent germination, delay index, speed of germination, peak value and germination period while growth parameters comprised of root and shoot length, root and shootweight, root-shoot ratio and number of stipules. The study showed the maximum values of positive germination parameters viz. speed of germination (7.85), peak value (3.28), germination index (123.87) and all growth parameters at 20% effluent concentration while the values of negative germination parameters viz. delay index (-0.14) and percent inhibition (-8.34) were found to be minimum at 20% effluent concentration. The study demonstrated that at lower concentrations the dyeing industry effluent caused a positive impact on germination and growth of Pisum sativum.

Factors Affecting Wound Healing

PubMed Central

Guo, S.; DiPietro, L.A.

2010-01-01

Wound healing, as a normal biological process in the human body, is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing. This article reviews the recent literature on the most significant factors that affect cutaneous wound healing and the potential cellular and/or molecular mechanisms involved. The factors discussed include oxygenation, infection, age and sex hormones, stress, diabetes, obesity, medications, alcoholism, smoking, and nutrition. A better understanding of the influence of these factors on repair may lead to therapeutics that improve wound healing and resolve impaired wounds. PMID:20139336

Factors affecting wound healing.

PubMed

Guo, S; Dipietro, L A

2010-03-01

Wound healing, as a normal biological process in the human body, is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing. This article reviews the recent literature on the most significant factors that affect cutaneous wound healing and the potential cellular and/or molecular mechanisms involved. The factors discussed include oxygenation, infection, age and sex hormones, stress, diabetes, obesity, medications, alcoholism, smoking, and nutrition. A better understanding of the influence of these factors on repair may lead to therapeutics that improve wound healing and resolve impaired wounds.

Effect of germination on bioactive compounds of soybean (Glycine max)

USDA-ARS?s Scientific Manuscript database

Germination is the practice of soaking, draining, and keeping seeds until they produce sprouts. The increasing interest in functional and healthy food products has promoted the use of germinated soybean flour in the manufacture of foods for human consumption. It is well known that germination induce...

Atmospheric ions and germination of uredospores of Puccinia striiformis

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

Sharp, E.L.

1967-06-09

Atmospheric ions, identified by mobility characteristics, were associated with germination of lyophilized uredospores of Puccinia striiformis West. at Bozeman, Montana. Ions of intermediate size were highest in concentration, and percentage germination of spores was lowest during periods conducive to air pollution. In duplicate experiments at an isolated site near Barrow, Alaska, essentially all atmospheric ions were small ions and the fungus spores were consistently germinated near maximum.

Effect of germination and thermal treatments on folates in rye.

PubMed

Kariluoto, Susanna; Liukkonen, Kirsi-Helena; Myllymäki, Olavi; Vahteristo, Liisa; Kaukovirta-Norja, Anu; Piironen, Vieno

2006-12-13

Effects of germination conditions and thermal processes on folate contents of rye were investigated. Total folate contents were determined microbiologically with Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism, and individual folates were determined by high-performance liquid chromatography after affinity chromatographic purification. Germination increased the folate content by 1.7-3.8-fold, depending on germination temperature, with a maximum content of 250 micro g/100 g dry matter. Hypocotylar roots with their notably high folate concentrations (600-1180 micro g/100 g dry matter) contributed 30-50% of the folate contents of germinated grains. Germination altered the proportions of folates, increasing the proportion of 5-methyltetrahydrofolate and decreasing the proportion of formylated folate compounds. Thermal treatments (extrusion, autoclaving and puffing, and IR and toasting) resulted in significant folate losses. However, folate levels in grains that were germinated and then were heat processed were higher than for native (nongerminated) grains. Opportunities to optimize rye processing to enhance folate levels in rye-based foods are discussed.

Soil warming increases plant species richness but decreases germination from the alpine soil seed bank.

PubMed

Hoyle, Gemma L; Venn, Susanna E; Steadman, Kathryn J; Good, Roger B; McAuliffe, Edward J; Williams, Emlyn R; Nicotra, Adrienne B

2013-05-01

Global warming is occurring more rapidly above the treeline than at lower elevations and alpine areas are predicted to experience above average warming in the future. Temperature is a primary factor in stimulating seed germination and regulating changes in seed dormancy status. Thus, plant regeneration from seed will be crucial to the persistence, migration and post disturbance recruitment of alpine plants in future climates. Here, we present the first assessment of the impact of soil warming on germination from the persistent alpine soil seed bank. Contrary to expectations, soil warming lead to reduced overall germination from the soil seed bank. However, germination response to soil temperature was species specific such that total species richness actually increased by nine with soil warming. We further explored the system by assessing the prevalence of seed dormancy and germination response to soil disturbance, the frequency of which is predicted to increase under climate change. Seeds of a significant proportion of species demonstrated physiological dormancy mechanisms and germination of several species appeared to be intrinsically linked to soil disturbance. In addition, we found no evidence of subalpine species and little evidence of exotic weed species in the soil, suggesting that the soil seed bank will not facilitate their invasion of the alpine zone. In conclusion, changes in recruitment via the alpine soil seed bank can be expected under climate change, as a result of altered dormancy alleviation and germination cues. Furthermore, the alpine soil seed bank, and the species richness therein, has the potential to help maintain local species diversity, support species range shift and moderate species dominance. Implications for alpine management and areas for further study are also discussed. © 2013 Blackwell Publishing Ltd.

Characterization of vibrissa germinative cells: transition of cell types.

PubMed

Osada, A; Kobayashi, K

2001-12-01

Germinative cells, small cell masses attached to the stalks of dermal papillae that are able to differentiate into the hair shaft and inner root sheath, form follicular bulb-like structures when co-cultured with dermal papilla cells. We studied the growth characteristics of germinative cells to determine the cell types in the vibrissa germinative tissue. Germinative tissues, attaching to dermal papillae, were cultured on 3T3 feeder layers. The cultured keratinocytes were harvested and transferred, equally and for two passages, onto lined dermal papilla cells (LDPC) and/or 3T3 feeder layers. The resulting germinative cells were classified into three types in the present experimental condition. Type 1 cells grow very well on either feeder layer, whereas Type 3 cells scarcely grow on either feeder layer. Type 2 cells are very conspicuous and are reversible. They grow well on 3T3 but growth is suppressed on LDPC feeder layers. The Type 2 cells that grow well on 3T3 feeder layers, however, are suppressed when transferred onto LDPC and the Type 2 cells that are suppressed on LDPC begin to grow again on 3T3. The transition of one cell type to another in vitro and the cell types that these germinative cell types correspond to in vivo is discussed. It was concluded that stem cells or their close progenitors reside in the germinative tissues of the vibrissa bulb except at late anagen-early catagen.

Measuring effects of music, noise, and healing energy using a seed germination bioassay.

PubMed

Creath, Katherine; Schwartz, Gary E

2004-02-01

To measure biologic effects of music, noise, and healing energy without human preferences or placebo effects using seed germination as an objective biomarker. A series of five experiments were performed utilizing okra and zucchini seeds germinated in acoustically shielded, thermally insulated, dark, humid growth chambers. Conditions compared were an untreated control, musical sound, pink noise, and healing energy. Healing energy was administered for 15-20 minutes every 12 hours with the intention that the treated seeds would germinate faster than the untreated seeds. The objective marker was the number of seeds sprouted out of groups of 25 seeds counted at 12-hour intervals over a 72-hour growing period. Temperature and relative humidity were monitored every 15 minutes inside the seed germination containers. A total of 14 trials were run testing a total of 4600 seeds. Musical sound had a highly statistically significant effect on the number of seeds sprouted compared to the untreated control over all five experiments for the main condition (p < 0.002) and over time (p < 0.000002). This effect was independent of temperature, seed type, position in room, specific petri dish, and person doing the scoring. Musical sound had a significant effect compared to noise and an untreated control as a function of time (p < 0.03) while there was no significant difference between seeds exposed to noise and an untreated control. Healing energy also had a significant effect compared to an untreated control (main condition, p < 0.0006) and over time (p < 0.0001) with a magnitude of effect comparable to that of musical sound. This study suggests that sound vibrations (music and noise) as well as biofields (bioelectromagnetic and healing intention) both directly affect living biologic systems, and that a seed germination bioassay has the sensitivity to enable detection of effects caused by various applied energetic conditions.

Red fox ( Vulpes vulpes L.) favour seed dispersal, germination and seedling survival of Mediterranean Hackberry ( Celtis australis L.)

NASA Astrophysics Data System (ADS)

Juan, Traba; Sagrario, Arrieta; Jesús, Herranz; Cristina, Clamagirand M.

2006-07-01

Seeds of the Mediterranean Hackberry Celtis australis are often encountered in fox faeces. In order to evaluate the effect of gut transit on the size of seeds selected, the rates and speed of germination and on the survival of the seedlings, Mediterranean Hackberry seeds from fox faeces were germinated in a greenhouse. The results were compared with those of seeds taken from ripe, uneaten fruits. Fox-dispersed seeds were smaller and lighter than the control ones and had higher (74% vs. 57%) and more rapid germination (74.5 days vs. 99.2 days). Seedlings from fox-dispersed seeds showed significantly greater survival by the end of the study period (74.1% vs. 43.6%) than the control ones. Survival in seedlings from fox-dispersed seeds was related to germination date, late seedlings showing poorer survival. This relationship was not observed away in the control seedlings. Seed mass did not affect seedling survival. Seedling arising from fox-dispersed seeds grew faster than control ones. These results suggest that fox can play a relevant role as seed disperser of Mediterranean Hackberry.

The role of cold cues at different life stages on germination and flowering phenology.

PubMed

Rubin, Matthew J; Friedman, Jannice

2018-04-23

The timing of major phenological transitions is critical to lifetime fitness, and life history theory predicts differences for annual and perennial plants. To correctly time these transitions, many plants rely on environmental cues such as exposure to extended periods of cold, which may occur at different stages throughout their lifetime. We studied the role of cold at different life stages, by jointly exposing seed (stratification) and rosettes (vernalization) to cold. We used 23 populations of Mimulus guttatus, which vary from annuals to perennials, and investigated how cold at one or both stages affected germination, flowering, growth, and biomass. We found that stratification and vernalization interact to affect life cycle transitions, and that cold at either stage could synchronize flowering phenology. For perennials, either stratification or vernalization is necessary for maximum flowering. We also found that germination timing covaried with later traits. Moreover, plants from environments with dissimilar climates displayed different phenological responses to stratification or vernalization. In general, cold is more important for seed germination in annuals and plants from environments with warm temperatures and variable precipitation. In contrast, cold is more important for flowering in perennials: it accelerates flowering in plants from lower precipitation environments, and it increases flowering proportion in plants from cooler, more stable precipitation environments. We discuss our findings in the context of the variable environments plants experience within a population and the variation encountered across the biogeographic native range of the species. © 2018 Botanical Society of America.

Seed Germination and Cuttings Growth of Piper Aduncum

NASA Astrophysics Data System (ADS)

Susanto, D.; Sudrajat; Suwinarti, W.; Amirta, R.

2018-04-01

Sirih hutan (Piper aduncum L) is one of group shurbs tropical species, has potential to be developed as raw material of biomass based electricity. The aim of this research was to know seed germination and cuttings growth of P. aduncum plant as the first step in cultivation of this plant. Observation of flowers and fruits were done in secondary forest, while seed germination and growth of shoot cuttings were done in the laboratory. The results showed that P. aduncum seeds can be germinated in a relatively short time of 17 to 25 days with a fairly high germination percentage of 90 ± 8.16% and germination rate of 4.7 ± 0.34%. The growth of seedlings at 2 months old was 4.78 ± 0.42 cm, plant height 3.97 ± 0.27 cm, and relative growth rate 0.33 ± 0.14%. The treatment of synthetic growth regulator had significant effect on shoot growth and root number on the plant stem cuttings. Preparation of seedlings ready to plant in a generative and vegetative for cultivation of these plants in the experimental plot.

Water uptake mechanism and germination of Erythrina velutina seeds treated with atmospheric plasma

NASA Astrophysics Data System (ADS)

Alves Junior, Clodomiro; de Oliveira Vitoriano, Jussier; da Silva, Dinnara Layza Souza; de Lima Farias, Mikelly; de Lima Dantas, Nadjamara Bandeira

2016-09-01

The effect of plasma applied to mulungu (Erythrina velutina) seeds was studied to verify its influence on the germination, water absorption, wettability and structure of the seeds. The plasma jet used in this study was produced by dielectric barrier discharge (DBD) in a helium gas flow of 0.03 L/s at a distance of 13 mm for 60 s. The plasma treatment significantly affected the seed germination rate, which was approximately 5% higher than that of the untreated group. Micropyle and hilum contributed a greater proportion to uptake. When sealed in the hilar or micropyle regions the amount of water absorbed into the seed decreased approximately 75% compared to the unsealed seed. This difference suggests that these two regions together act cooperatively in the water absorption. However, when plasma treated seed was blocked in the micropyle region, water absorption was higher higher than in seeds blocked hilum. This difference suggests that the plasma treatment changed the wettability of the hilum more effectively than it changed the micropyle. These results indicate that plasma can significantly change the hydrophilicity, water absorption and percentage of seed germination in E. velutina.

Inhibitors of protein phosphorylation including the retinoblastoma protein induce germination of Candida albicans.

PubMed

Cho, T; Hamatake, H; Hagihara, Y; Kaminishi, H

2000-02-01

It has been previously shown that the induction of germination in Candida albicans occurs following its cessation of growth as a yeast. Similarly, mammalian cells undergo a differentiation process that is preceded by a growth cessation associated with a hypophosphorylation of proteins of the retinoblastoma gene family. It is postulated that a similar type of mechanism may be operative in C. albicans and protein phosphorylation inhibitors: forskolin (stimulates cyclic adenosine monophosphate production), okadaic acid (phosphatase inhibitor) and D-erythro-sphingosine (retinoblastoma protein phosphorylation inhibitor) have been used to further strengthen this hypothesis. Okadaic acid (1-1000 nM) and D-erythro-sphingosine (100 microM) significantly inhibited the growth of yeast cells of C. albicans. D-Erythro-sphingosine at 1000 microM was candidicidal. Forskolin did not significantly affect growth. Exponentially grown C. albicans pretreated with forskolin (10 microM), okadaic acid (1000 nM) or D-erythro-sphingosine (100 microM) readily germinated. In comparison, when these inhibitors were incorporated in the same medium, germination of exponentially grown cells did not occur. These results suggest that protein dephosphorylation may be necessary at an early stage of the yeast-hyphae transition in C. albicans.

Seed germination ecology of feather lovegrass [Eragrostis tenella (L.) Beauv. Ex Roemer & J.A. Schultes].

PubMed

Chauhan, Bhagirath S

2013-01-01

Feather lovegrass [Eragrostis tenella (L.) Beauv. Ex Roemer & J.A. Schultes] is a C4 grass weed that has the ability to grow in both lowland and upland conditions. Experiments were conducted in the laboratory and screenhouse to evaluate the effect of environmental factors on germination, emergence, and growth of this weed species. Germination in the light/dark regime was higher at alternating day/night temperatures of 30/20 °C (98%) than at 35/25 °C (83%) or 25/15 °C (62%). Germination was completely inhibited by darkness. The osmotic potential and sodium chloride concentrations required for 50% inhibition of maximum germination were -0.7 MPa and 76 mM, respectively. The highest seedling emergence (69%) was observed from the seeds sown on the soil surface and no seedlings emerged from seeds buried at depths of 0.5 cm or more. The use of residue as mulches significantly reduced the emergence and biomass of feather lovegrass seedlings. A residue amount of 0.5 t ha(-1) was needed to suppress 50% of the maximum seedlings. Because germination was strongly stimulated by light and seedling emergence was the highest for the seeds sown on the soil surface, feather lovegrass is likely to become a problematic weed in zero-till systems. The knowledge gained from this study could help in developing effective and sustainable weed management strategies.

α-Xylosidase plays essential roles in xyloglucan remodelling, maintenance of cell wall integrity, and seed germination in Arabidopsis thaliana

PubMed Central

Shigeyama, Takuma; Watanabe, Asuka; Tokuchi, Konatsu; Toh, Shigeo; Sakurai, Naoki; Shibuya, Naoto; Kawakami, Naoto

2016-01-01

Regulation and maintenance of cell wall physical properties are crucial for plant growth and environmental response. In the germination process, hypocotyl cell expansion and endosperm weakening are prerequisites for dicot seeds to complete germination. We have identified the Arabidopsis mutant thermoinhibition-resistant germination 1 (trg1), which has reduced seed dormancy and insensitivity to unfavourable conditions for germination owing to a loss-of-function mutation of TRG1/XYL1, which encodes an α-xylosidase. Compared to those of wild type, the elongating stem of trg1 showed significantly lower viscoelasticity, and the fruit epidermal cells were longitudinally shorter and horizontally enlarged. Actively growing tissues of trg1 over-accumulated free xyloglucan oligosaccharides (XGOs), and the seed cell wall had xyloglucan with a greatly reduced molecular weight. These observations suggest that XGOs reduce xyloglucan size by serving as an acceptor in transglycosylation and eventually enhancing cell wall loosening. TRG1/XYL1 gene expression was abundant in growing wild-type organs and tissues but relatively low in cells at most actively elongating part of the tissues, suggesting that α-xylosidase contributes to maintaining the mechanical integrity of the primary cell wall in the growing and pre-growing tissues. In germinating seeds of trg1, expression of genes encoding specific abscisic acid and gibberellin metabolism enzymes was altered in accordance with the aberrant germination phenotype. Thus, cell wall integrity could affect seed germination not only directly through the physical properties of the cell wall but also indirectly through the regulation of hormone gene expression. PMID:27605715

Optimum germination temperatures

Treesearch

Richard M. Godman; Gilbert A. Mattson

1992-01-01

Why is sugar maple abundant under nearly all stand conditions, and why do hemlock and yellow birch, although differing in tolerance, occur together as a type? At least part of the answer may have to do with the optimum germinating temperatures for their seeds.

Factors Affecting Sign Retroreflectivity : final report.

DOT National Transportation Integrated Search

2001-01-01

This study was undertaken to better understand the factors that may affect road sign retroreflectivity, specifically age and physical orientation. A better understanding of these factors could provide guidance to ODOT in managing its inventory of roa...

HFR1 Sequesters PIF1 to Govern the Transcriptional Network Underlying Light-Initiated Seed Germination in Arabidopsis[C][W][OPEN

PubMed Central

Shi, Hui; Zhong, Shangwei; Mo, Xiaorong; Liu, Na; Nezames, Cynthia D.; Deng, Xing Wang

2013-01-01

Seed germination is the first step for seed plants to initiate a new life cycle. Light plays a predominant role in promoting seed germination, where the initial phase is mediated by photoreceptor phytochrome B (phyB). Previous studies showed that PHYTOCHROME-INTERACTING FACTOR1 (PIF1) represses seed germination downstream of phyB. Here, we identify a positive regulator of phyB-dependent seed germination, LONG HYPOCOTYL IN FAR-RED1 (HFR1). HFR1 blocks PIF1 transcriptional activity by forming a heterodimer with PIF1 that prevents PIF1 from binding to DNA. Our whole-genomic analysis shows that HFR1 and PIF1 oppositely mediate the light-regulated transcriptome in imbibed seeds. Through the HFR1–PIF1 module, light regulates expression of numerous genes involved in cell wall loosening, cell division, and hormone pathways to initiate seed germination. The functionally antagonistic HFR1–PIF1 pair constructs a fail-safe mechanism for fine-tuning seed germination during low-level illumination, ensuring a rapid response to favorable environmental changes. This study identifies the HFR1–PIF1 pair as a central module directing the whole genomic transcriptional network to rapidly initiate light-induced seed germination. PMID:24179122

Allelopathic effect of Ashwagandha against the germination and radicle growth of Cicer arietinum and Triticum aestivum

PubMed Central

Chandra, Sangita; Chatterjee, Priyanka; Dey, Protapaditya; Bhattacharya, Sanjib

2012-01-01

Background: Ashwagandha (Withania somnifera) is an important medicinal plant in Indian traditional system of medicine and traditionally has been used for several medicinal purposes in the Indian subcontinent. Objective: The present study was aimed at the evaluation of allelopathic effect of hydroalcoholic extract of ashwagandha against germination and radicle growth of Cicer arietinum and Triticum aestivum seeds. Materials and Methods: The extract at different concentrations was incubated in controlled conditions with the surface sterilized seeds of C. arietinum and T. aestivum and observed periodically for seed germination and radicle growth to assess the allelopathic behavior. Results: The extract mainly at higher concentrations demonstrated promising allelopathic potential by significantly affecting seed germination and radicle elongation of both C. arietinum and T. aestivum in a concentration dependent manner. T. aestivum was found to be more sensitive than C. arietinum. Conclusion: The present study demonstrated remarkable allelopathic potential of ashwagandha against the test seeds. The effect was plausibly due to the alkaloid and withanolide contents of ashwagandha. PMID:22923955

Allelopathic effect of Ashwagandha against the germination and radicle growth of Cicer arietinum and Triticum aestivum.

PubMed

Chandra, Sangita; Chatterjee, Priyanka; Dey, Protapaditya; Bhattacharya, Sanjib

2012-07-01

Ashwagandha (Withania somnifera) is an important medicinal plant in Indian traditional system of medicine and traditionally has been used for several medicinal purposes in the Indian subcontinent. The present study was aimed at the evaluation of allelopathic effect of hydroalcoholic extract of ashwagandha against germination and radicle growth of Cicer arietinum and Triticum aestivum seeds. The extract at different concentrations was incubated in controlled conditions with the surface sterilized seeds of C. arietinum and T. aestivum and observed periodically for seed germination and radicle growth to assess the allelopathic behavior. The extract mainly at higher concentrations demonstrated promising allelopathic potential by significantly affecting seed germination and radicle elongation of both C. arietinum and T. aestivum in a concentration dependent manner. T. aestivum was found to be more sensitive than C. arietinum. The present study demonstrated remarkable allelopathic potential of ashwagandha against the test seeds. The effect was plausibly due to the alkaloid and withanolide contents of ashwagandha.

[Study on physiological and germination characteristics of Tulipa edulis seed].

PubMed

Wu, Zhengjun; Zhu, Zaibiao; Guo, Qiaosheng; Ma, Hongliang; Xu, Hongjian; Miao, Yuanyuan

2012-03-01

Current study was conducted to investigate the seed physiological characteristics of Tulipa edulis and improve germination rate. Anatomical characteristics was observed. Seed water absorption curve was tested by soaking method. Dynamic of embryo development and germination rate as well as germination index under different conditions were recorded. And the biological test of cabbage seed was used for detecting the germination inhibitors. The embryo rate of newly matured seeds was about 10%, and there was no obstacle of water absorption on testa of T. edulis. The optimum method for embryo development was exposure to 300 mg x L(-1) gibberellin solution for 24 hours, and stratification at 25 degrees C for 70 days followed by stratification at 5 degrees C for 40 days. The germintion rate and germination index of dormancy-broken seeds under the dark environment at 10 degrees C and 15 degrees C were significantly higher than those under other conditions. Additionally, there were some germination inhibitory substances in dry seeds. The seed of T. edulis can be classified as having complex morphophysiological dormancy, and the morphological embryo dormancy played a leading role. Warm and cold stratification resulted in a fast dormancy breaking effect, and a high germination rate more than 90% could be obtained under the optimum conditions.

Quantitative proteomics revealed partial fungistatic mechanism of ammonia against conidial germination of nematode-trapping fungus Arthrobotrys oligospora ATCC24927.

PubMed

Liu, Tong; Tian, Dong-Wei; Zou, Li-Juan; Liu, Fang-Yu; Can, Qi-Yan; Yang, Jin-Kui; Xu, Jian-Ping; Huang, Xiao-Wei; Xi, Jia-Qin; Zhu, Ming-Liang; Mo, Ming-He; Zhang, Ke-Qin

2018-05-01

Ammonia is one of the fungistatic factors in soil that can suppress conidial germination, but the molecular mechanism underlying the suppression is unknown. In this study, the proteomes of fungistatic conidia, fresh conidia and germinated conidia of Arthrobotrys oligospora ATCC24927 were determined and quantified. The protein expression profile of fungistatic conidia was significantly different from those in the other two conditions. 281 proteins were down expressed in fungistatic conidia and characterized by GO annotation. Gene transcription analysis and inhibition of puromycin (a protein translation inhibitor) on conidial germination suggested that down expression of 33 protein translation related proteins might well result in repression of protein synthesis and inhibition of conidial germination. In addition, 16 down-expressed proteins were mapped to the Ras/mitogen-activated protein (Ras/MAP) regulatory networks which regulate conidial DNA synthesis. The conidial DNA synthesis was found to be definitely inhibited under by ammonia, and function studies of two Ras/MAP proteins by using knock-out strains provided partial evidence that Ras/MAP pathway regulate the conidial germination. These results suggested that down-expression of Ras/MAP related proteins might result in inhibition of DNA synthesis and finally result in inhibition conidial germination. This study revealed partial fungistatic mechanism of ammonia against conidial germination. Copyright © 2018 Elsevier Ltd. All rights reserved.

Aberrant Meiotic Modulation Partially Contributes to the Lower Germination Rate of Pollen Grains in Maize (Zea mays L.) Under Low Nitrogen Supply.

PubMed

Zheng, Hongyan; Wu, Huamao; Pan, Xiaoying; Jin, Weiwei; Li, Xuexian

2017-02-01

Pollen germination is an essential step towards successful pollination during maize reproduction. How low niutrogen (N) affects pollen germination remains an interesting biological question to be addressed. We found that only low N resulted in a significantly lower germination rate of pollen grains after 4 weeks of low N, phosphorus or potassium treatment in maize production. Importantly, cytological analysis showed 7-fold more micronuclei in male meiocytes under the low N treatment than in the control, indicating that the lower germination rate of pollen grains was partially due to numerous chromosome loss events resulting from preceding meiosis. The appearance of 10 bivalents in the control and low N cells at diakinesis suggested that chromosome pairing and recombination in meiosis I was not affected by low N. Further gene expression analysis revealed dramatic down-regulation of Nuclear Division Cycle 80 (Ndc80) and Regulator of Chromosome Condensation 1 (Rcc1-1) expression and up-regulation of Cell Division Cycle 20 (Cdc20-1) expression, although no significant difference in the expression level of kinetochore foundation proteins Centromeric Histone H3 (Cenh3) and Centromere Protein C (Cenpc) and cohesion regulators Recombination 8 (Rec8) and Shugoshin (Sgo1) was observed. Aberrant modulation of three key meiotic regulators presumably resulted in a high likelihood of erroneous chromosome segregation, as testified by pronounced lagging chromosomes at anaphase I or cell cycle disruption at meiosis II. Thus, we proposed a cytogenetic mechanism whereby low N affects male meiosis and causes a higher chromosome loss frequency and eventually a lower germination rate of pollen grains in a staple crop plant. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Spore germination and gametophyte development of Cyathea atrovirens (Langsd. & Fisch.) Domin (Cyatheaceae) under different pH conditions.

PubMed

Rechenmacher, C; Schmitt, J L; Droste, A

2010-12-01

Cyathea atrovirens (Langsd. & Fisch.) Domin, an intensely exploited tree fern, is found inside forests in several succession stages, as well as in swamps, roadsides and unused fields in the Rio dos Sinos basin, in the state of Rio Grande do Sul, southern Brazil. This study evaluated the in vitro germination and gametophyte development of C. atrovirens under different pH conditions, as well as spore viability after different storage times at 7 ºC. The lowest germination rate of spores was obtained at pH 7.0. At pH 5.0 to 6.5, laminar gametophyte development started at 20 to 30 days of culture. Antheridia and archegonia were first observed at 35 and 128 days, respectively. Storage at 7 ºC did not affect germination rates. The capability of germination at different pH levels may explain the occurrence of the species in a wide range of habitats. The present study contributes to the understanding of the full life-cycle of C. atrovirens and to the analysis of the influence of abiotic components, providing information for the cultivation, management and conservation of the species.

Arabidopsis Glutamate Receptor Homolog3.5 Modulates Cytosolic Ca2+ Level to Counteract Effect of Abscisic Acid in Seed Germination1[OPEN

PubMed Central

Kong, Dongdong; Ju, Chuanli; Parihar, Aisha; Kim, So; Cho, Daeshik; Kwak, June M.

2015-01-01

Seed germination is a critical step in a plant’s life cycle that allows successful propagation and is therefore strictly controlled by endogenous and environmental signals. However, the molecular mechanisms underlying germination control remain elusive. Here, we report that the Arabidopsis (Arabidopsis thaliana) glutamate receptor homolog3.5 (AtGLR3.5) is predominantly expressed in germinating seeds and increases cytosolic Ca2+ concentration that counteracts the effect of abscisic acid (ABA) to promote germination. Repression of AtGLR3.5 impairs cytosolic Ca2+ concentration elevation, significantly delays germination, and enhances ABA sensitivity in seeds, whereas overexpression of AtGLR3.5 results in earlier germination and reduced seed sensitivity to ABA. Furthermore, we show that Ca2+ suppresses the expression of ABSCISIC ACID INSENSITIVE4 (ABI4), a key transcription factor involved in ABA response in seeds, and that ABI4 plays a fundamental role in modulation of Ca2+-dependent germination. Taken together, our results provide molecular genetic evidence that AtGLR3.5-mediated Ca2+ influx stimulates seed germination by antagonizing the inhibitory effects of ABA through suppression of ABI4. These findings establish, to our knowledge, a new and pivotal role of the plant glutamate receptor homolog and Ca2+ signaling in germination control and uncover the orchestrated modulation of the AtGLR3.5-mediated Ca2+ signal and ABA signaling via ABI4 to fine-tune the crucial developmental process, germination, in Arabidopsis. PMID:25681329

Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest.

PubMed

Sarmiento, Carolina; Zalamea, Paul-Camilo; Dalling, James W; Davis, Adam S; Stump, Simon M; U'Ren, Jana M; Arnold, A Elizabeth

2017-10-24

The Janzen-Connell (JC) hypothesis provides a conceptual framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet-that recruits experience high mortality near conspecifics and at high densities-assumes a degree of host specialization in interactions between plants and natural enemies. Studies confirming JC effects have focused primarily on spatial distributions of seedlings and saplings, leaving major knowledge gaps regarding the fate of seeds in soil and the specificity of the soilborne fungi that are their most important antagonists. Here we use a common garden experiment in a lowland tropical forest in Panama to show that communities of seed-infecting fungi are structured predominantly by plant species, with only minor influences of factors such as local soil type, forest characteristics, or time in soil (1-12 months). Inoculation experiments confirmed that fungi affected seed viability and germination in a host-specific manner and that effects on seed viability preceded seedling emergence. Seeds are critical components of reproduction for tropical trees, and the factors influencing their persistence, survival, and germination shape the populations of seedlings and saplings on which current perspectives regarding forest dynamics are based. Together these findings bring seed dynamics to light in the context of the JC hypothesis, implicating them directly in the processes that have emerged as critical for diversity maintenance in species-rich tropical forests.

Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest

PubMed Central

Dalling, James W.; Stump, Simon M.; U’Ren, Jana M.; Arnold, A. Elizabeth

2017-01-01

The Janzen–Connell (JC) hypothesis provides a conceptual framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet—that recruits experience high mortality near conspecifics and at high densities—assumes a degree of host specialization in interactions between plants and natural enemies. Studies confirming JC effects have focused primarily on spatial distributions of seedlings and saplings, leaving major knowledge gaps regarding the fate of seeds in soil and the specificity of the soilborne fungi that are their most important antagonists. Here we use a common garden experiment in a lowland tropical forest in Panama to show that communities of seed-infecting fungi are structured predominantly by plant species, with only minor influences of factors such as local soil type, forest characteristics, or time in soil (1–12 months). Inoculation experiments confirmed that fungi affected seed viability and germination in a host-specific manner and that effects on seed viability preceded seedling emergence. Seeds are critical components of reproduction for tropical trees, and the factors influencing their persistence, survival, and germination shape the populations of seedlings and saplings on which current perspectives regarding forest dynamics are based. Together these findings bring seed dynamics to light in the context of the JC hypothesis, implicating them directly in the processes that have emerged as critical for diversity maintenance in species-rich tropical forests. PMID:28973927

Germination rate is the significant characteristic determining coconut palm diversity

PubMed Central

Harries, Hugh C.

2012-01-01

Rationale This review comes at a time when in vitro embryo culture techniques are being adopted for the safe exchange and cryo-conservation of coconut germplasm. In due course, laboratory procedures may replace the options that exist among standard commercial nursery germination techniques. These, in their turn, have supplanted traditional methods that are now forgotten or misunderstood. Knowledge of all germination options should help to ensure the safe regeneration of conserved material. Scope This review outlines the many options for commercial propagation, recognizes the full significance of one particular traditional method and suggests that the diversity of modern cultivated coconut varieties has arisen because natural selection and domestic selection were associated with different rates of germination and other morphologically recognizable phenotypic characteristics. The review takes into account both the recalcitrant and the viviparous nature of the coconut. The ripe fruits that fall but do not germinate immediately and lose viability if dried for storage are contrasted with the bunches of fruit retained in the crown of the palm that may, in certain circumstances, germinate to produce seedlings high above ground level. Significance Slow-germinating and quick-germinating coconuts have different patterns of distribution. The former predominate on tropical islands and coastlines that could be reached by floating when natural dispersal originally spread coconuts widely—but only where tides and currents were favourable—and then only to sea-level locations. Human settlers disseminated the domestic types even more widely—to otherwise inaccessible coastal sites not reached by floating—and particularly to inland and upland locations on large islands and continental land masses. This review suggests four regions where diversity has been determined by germination rates. Although recent DNA studies support these distinctions, further analyses of genetic markers

Germination rate is the significant characteristic determining coconut palm diversity.

PubMed

Harries, Hugh C

2012-01-01

This review comes at a time when in vitro embryo culture techniques are being adopted for the safe exchange and cryo-conservation of coconut germplasm. In due course, laboratory procedures may replace the options that exist among standard commercial nursery germination techniques. These, in their turn, have supplanted traditional methods that are now forgotten or misunderstood. Knowledge of all germination options should help to ensure the safe regeneration of conserved material. This review outlines the many options for commercial propagation, recognizes the full significance of one particular traditional method and suggests that the diversity of modern cultivated coconut varieties has arisen because natural selection and domestic selection were associated with different rates of germination and other morphologically recognizable phenotypic characteristics. The review takes into account both the recalcitrant and the viviparous nature of the coconut. The ripe fruits that fall but do not germinate immediately and lose viability if dried for storage are contrasted with the bunches of fruit retained in the crown of the palm that may, in certain circumstances, germinate to produce seedlings high above ground level. Slow-germinating and quick-germinating coconuts have different patterns of distribution. The former predominate on tropical islands and coastlines that could be reached by floating when natural dispersal originally spread coconuts widely-but only where tides and currents were favourable-and then only to sea-level locations. Human settlers disseminated the domestic types even more widely-to otherwise inaccessible coastal sites not reached by floating-and particularly to inland and upland locations on large islands and continental land masses. This review suggests four regions where diversity has been determined by germination rates. Although recent DNA studies support these distinctions, further analyses of genetic markers related to fruit abscission and

REVERSIBLE ACTIVATION FOR GERMINATION AND SUBSEQUENT CHANGES IN BACTERIAL SPORES1

PubMed Central

Lee, W. H.; Ordal, Z. John

1963-01-01

Lee, W. H. (University of Illinois, Urbana) and Z. John Ordal. Reversible activation for germination and subsequent changes in bacterial spores. J. Bacteriol. 85:207–217. 1963.—It was possible to isolate refractile spores of Bacillus megaterium, from a calcium dipicolinate germination solution, that were activated and would germinate spontaneously in distilled water. Some of the characteristics of the initial phases of bacterial spore germination were determined by studying these unstable activated spores. Activated spores of B. megaterium were resistant to stains and possessed a heat resistance intermediate between that of dormant and of germinated spores. The spontaneous germination of activated spores was inhibited by copper, iron, silver, or mercury salts, saturated o-phenanthroline, or solutions having a low pH value, but not by many common inhibitors. These inhibitions could be partially or completely reversed by the addition of sodium dipicolinate. The activated spores could be deactivated and made similar to dormant spores by treatment with acid. Analyses of the exudates from the variously treated spore suspensions revealed that whatever inhibited the germination of activated spores also inhibited the release of spore material. The composition of the germination exudates was different than that of extracts of dormant spores. Although heavy suspensions of activated spores gradually became swollen and dark when suspended in solutions of o-phenanthroline or at pH 4, the materials released resembled those found in extracts of dormant spores rather than those of normal germination exudates. Images PMID:16561987

Germination of Sweetgum in Response to Temherature, Moisture Stress, and Length of Stratification

Treesearch

F. T. Bonner; R. E. Farmer

1966-01-01

Both total germination and rate of germination of sweetgum seed increased as temperatures were raised from 60-75 to 85-100°F. Increases in osmotic stress lessened total germination and rate of germination, and 15 atmospheres of stress completely inhibited germination. Raising the temperatures decreased the influence of osmotic stress, and lengthening the stratification...

Omethoate treatment mitigates high salt stress inhibited maize seed germination.

PubMed

Yang, Kejun; Zhang, Yifei; Zhu, Lianhua; Li, Zuotong; Deng, Benliang

2018-01-01

Omethoate (OM) is a highly toxic organophophate insecticide, which is resistant to biodegradation in the environment and is widely used for pest control in agriculture. The effect of OM on maize seed germination was evaluated under salt stress. Salt (800mM) greatly reduced germination of maize seed and this could be reversed by OM. Additionally, H 2 O 2 treatment further improved the effect of OM on seed germination. Higher H 2 O 2 content was measured in OM treated seed compared to those with salt stress alone. Dimethylthiourea (DTMU), a specific scavenger of reactive oxygen species (ROS), inhibited the effect of OM on seed germination, as did IMZ (imidazole), an inhibitor of NADPH oxidase. Abscisic acid (ABA) inhibited the effect of OM on seed germination, whereas fluridone, a specific inhibitor of ABA biosynthesis, enhanced the effect of OM. Taken together, these findings suggest a role of ROS and ABA in the promotion of maize seed germination by OM under salt stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Conditional cold avoidance drives between-population variation in germination behaviour in Calluna vulgaris.

PubMed

Spindelböck, Joachim P; Cook, Zoë; Daws, Matthew I; Heegaard, Einar; Måren, Inger E; Vandvik, Vigdis

2013-09-01

Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season. Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range. Incubation treatments varied from 10 to 25 °C, and germination performance across populations was analysed in relation to temperature conditions at the seed collection locations. Seeds from all populations germinated rapidly and to high final percentages under the warmer incubation temperatures. Under low incubation temperatures, cold-climate populations had significantly lower germination rates and percentages than warm-climate populations. While germination rates and percentages also increased with seed mass, seed mass did not vary along the climatic gradients, and therefore did not explain the variation in germination responses. Variation in germination responses among Calluna populations was consistent with increased temperature requirements for germination towards colder climates, indicating a cold-avoidance germination strategy conditional on the temperature at the seeds' origin. Along a gradient of increasing temperatures this suggests a shift in selection pressures on germination from climatic adversity (i.e. low temperatures and potential frost risk in early or late season) to competitive performance and better exploitation of the

The COP9 Signalosome regulates seed germination by facilitating protein degradation of RGL2 and ABI5

PubMed Central

Li, Bosheng; Bücker, Birte; Keil, Philipp; Zhang, Shaoman; Li, Jigang; Kang, Dingming; Liu, Jie; Dong, Jie; Deng, Xing Wang; Irish, Vivian

2018-01-01

The control of seed germination and seed dormancy are critical for the successful propagation of plant species, and are important agricultural traits. Seed germination is tightly controlled by the balance of gibberellin (GA) and abscisic acid (ABA), and is influenced by environmental factors. The COP9 Signalosome (CSN) is a conserved multi-subunit protein complex that is best known as a regulator of the Cullin-RING family of ubiquitin E3 ligases (CRLs). Multiple viable mutants of the CSN showed poor germination, except for csn5b-1. Detailed analyses showed that csn1-10 has a stronger seed dormancy, while csn5a-1 mutants exhibit retarded seed germination in addition to hyperdormancy. Both csn5a-1 and csn1-10 plants show defects in the timely removal of the germination inhibitors: RGL2, a repressor of GA signaling, and ABI5, an effector of ABA responses. We provide genetic evidence to demonstrate that the germination phenotype of csn1-10 is caused by over-accumulation of RGL2, a substrate of the SCF (CRL1) ubiquitin E3 ligase, while the csn5a-1 phenotype is caused by over-accumulation of RGL2 as well as ABI5. The genetic data are consistent with the hypothesis that CSN5A regulates ABI5 by a mechanism that may not involve CSN1. Transcriptome analyses suggest that CSN1 has a more prominent role than CSN5A during seed maturation, but CSN5A plays a more important role than CSN1 during seed germination, further supporting the functional distinction of these two CSN genes. Our study delineates the molecular targets of the CSN complex in seed germination, and reveals that CSN5 has additional functions in regulating ABI5, thus the ABA signaling pathway. PMID:29462139

The ultraviolet radiation environment of pollen and its effect on pollen germination

NASA Technical Reports Server (NTRS)

1981-01-01

The damage to pollen caused by natural ultraviolet radiation was investigated. Experimental and literature research into the UV radiation environment is reported. Viability and germination of wind and insect pollinated species were determined. Physiological, developmental, and protective factors influencing UV sensitivity of binucleate, advanced binucleate, and trinucleate pollen grains are compared.

Modeling the Effect of Density-Dependent Chemical Interference Upon Seed Germination

PubMed Central

Sinkkonen, Aki

2005-01-01

A mathematical model is presented to estimate the effects of phytochemicals on seed germination. According to the model, phytochemicals tend to prevent germination at low seed densities. The model predicts that at high seed densities they may increase the probability of seed germination and the number of germinating seeds. Hence, the effects are reminiscent of the density-dependent effects of allelochemicals on plant growth, but the involved variables are germination probability and seedling number. The results imply that it should be possible to bypass inhibitory effects of allelopathy in certain agricultural practices and to increase the efficiency of nature conservation in several plant communities. PMID:19330163

Modeling the Effect of Density-Dependent Chemical Interference upon Seed Germination

PubMed Central

Sinkkonen, Aki

2006-01-01

A mathematical model is presented to estimate the effects of phytochemicals on seed germination. According to the model, phytochemicals tend to prevent germination at low seed densities. The model predicts that at high seed densities they may increase the probability of seed germination and the number of germinating seeds. Hence, the effects are reminiscent of the density-dependent effects of allelochemicals on plant growth, but the involved variables are germination probability and seedling number. The results imply that it should be possible to bypass inhibitory effects of allelopathy in certain agricultural practices and to increase the efficiency of nature conservation in several plant communities. PMID:18648596

Bimolecular fluorescence complementation studies support an in vivo interaction between the F-BOX protein COLD TEMPERATURE GERMINATING10 and PHYTOCHROME INTERACTING FACTOR1

USDA-ARS?s Scientific Manuscript database

The Arabidopsis thaliana F-BOX protein COLD TEMPERATURE GERMINATING10 (CTG10) was identified from an activation tagged mutant screen as causing seeds to complete germination faster than wild type at 10°C when its expression is increased (Salaita et al. 2005. J. Exp. Bot. 56: 2059). Our unpublished d...

Comparison of Germination and Viability Tests for Southern Hardwood Seed

Treesearch

F. T. Bonner; J. L. Gammage

1967-01-01

This paper summarizes a 3-year evaluation of 10 methods for testing germinability and viability of the seed of six species of southern hardwood. In five of the methods, the seeds were germinated. In the others, visual, biochemical, or physical properties were the criteria. Cutting tests were best for sweetgum and Nuttall oak seed, while cutting or water germination...

Enhanced germination and gravitropism of soybean in a hypogeomagnetic field

NASA Astrophysics Data System (ADS)

Mo, Weichuan

For the future manned space exploration, the duration of the missions would significantly in-crease. Investigating plant growth and development under the space environmental conditions is of essential importance for the food supply projects for the astronauts. Hypogeomagnetic field (HGMF), namely, extremely low magnetic field, is one of the main characters of the space environment. Germination is the first vital step of plant growth and development, which determines the final yield of plants. The effect of HGMF on plant growth, especially early ger-mination, still remains open. In this study, we established a hypogeomagnetic field (HGMF) incubation system, the remnant magnetic field inside no more than 250 nT. Soybean seeds were incubated at 25 in HGMF, and the very beginning of soybean germination, from water ab-sorbance of cotyledon to radicle emergence, was examined within 24 h. Our results showed that the germination ratio and weight ratio of emerged soybean radicles were markedly increased during germination in HGMF. Furthermore, the tropism angle of emerged radicle with gravity in HGMF was statistically smaller than that in GMF when the radicle direction was placed opposite to gravity before germination. These results indicate that the germination and gravit-ropism of soybean is enhanced in a hypogeomagnetic environment, This is a new finding about the early seed germination in such a low environmental magnetic field which is comparable to the magnetic field of Lunar Swirls on the Moon (a few hundred nT), and it might provide new perspectives on the space science researches concerning plant growth and food supply.

Sodium nitrite and sorbic acid effects on Clostridium botulinum spore germination and total microbial growth in chicken frankfurter emulsions during temperature abuse.

PubMed Central

Sofos, J N; Busta, F F; Allen, C E

1979-01-01

Samples of (i) a control or of (ii) sodium nitrite-containing or (iii) sorbic acid-containing, mechanically deboned chicken meat frankfurter-type emulsions inoculated with Clostridium botulinum spores, or a combination of ii and iii, were temperature abuse at 27 degrees C. Spore germination and total microbial growth were followed and examined at specified times and until toxic samples were detected. The spores germinated within 3 days in both control and nitrite (20, 40 and 156 micrograms/g) treatments. Sorbic acid (0.2%) alone or in combination with nitrite (20, 40, and 156 micrograms/g) significantly (P less than 0.05) inhibited spore germinations. No significant germination was recorded until toxic samples were detected. A much longer incubation period was necessary for toxin to be formed in nitrite-sorbic acid combination treatments as contrasted with controls or nitrite and sorbic acid used individually. Total growth was not affected by the presence of nitrite, whereas sorbic acid appeared to depress it. Possible mechanisms explaining the effects of nitrite and sorbic acid on spore germination and growth are postulated. PMID:384904

Sodium chloride effects on lipase activity in germinating rape seeds.

PubMed

Ben Miled, D D; Zarrouk, M; Chérif, A

2000-12-01

Seeds of rape (Brassica napus L.) were germinated at various NaCl concentrations up to 200 mM. Germinating levels, seedling growth, triacylglycerol mobilization and lipase activity were investigated. High salt concentrations resulted in retardation of seed germination. Seedling growth as measured by radicle length was severely reduced by NaCl doses higher than 50 mM. Moreover, the mobilization of storage oil in control rapeseed seedlings, started about 24 h after imbibition. As for germination and growth, elevated salt concentrations are found to delay triacylglycerol degradation. Experiments using triolein as substrate indicated clearly that lipase activity was inhibited by salt treatment.

Characterization and Quantitation of Triterpenoid Saponins in Raw and Sprouted Chenopodium berlandieri spp. (Huauzontle) Grains Subjected to Germination with or without Selenium Stress Conditions.

PubMed

Lazo-Vélez, Marco A; Guajardo-Flores, Daniel; Mata-Ramírez, Daniel; Gutiérrez-Uribe, Janet A; Serna-Saldivar, Sergio O

2016-01-01

Pseudocereal Chenopodium berlandieri spp. (huauzontle) was evaluated to determine saponin composition. Saponins were evaluated in raw and germinated grains subjected to chemical stress induced by sodium selenite. Analysis by liquid chromatography coupled with ELSD detector revealed the presence of 12 saponins, identified according to compounds previously assayed in Chenopodium quinoa. Saponins found at the highest concentrations in raw grains were derived from oleanolic and phytolaccagenic acids. Total saponin concentration significantly decreased in germinated compared to raw grains due to the significant loss of 90.1% and 95.7% of the phytolaccagenic acid without and with chemical selenium stress, respectively. The most abundant saponin in germinated sprouts decreased during normal germination. Interestingly, the concentration of this particular saponin significantly increased during the Se-induced stress germination. Chemical stress with selenium salts proved to change the saponin composition in geminated Chenopodium berlandieri spp. grains, therefore affecting their potential use as ingredient in the food industry. © 2015 Institute of Food Technologists®

Conditional cold avoidance drives between-population variation in germination behaviour in Calluna vulgaris

PubMed Central

Spindelböck, Joachim P.; Cook, Zoë; Daws, Matthew I.; Heegaard, Einar; Måren, Inger E.; Vandvik, Vigdis

2013-01-01

Background and Aims Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season. Methods Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range. Incubation treatments varied from 10 to 25 °C, and germination performance across populations was analysed in relation to temperature conditions at the seed collection locations. Key Results Seeds from all populations germinated rapidly and to high final percentages under the warmer incubation temperatures. Under low incubation temperatures, cold-climate populations had significantly lower germination rates and percentages than warm-climate populations. While germination rates and percentages also increased with seed mass, seed mass did not vary along the climatic gradients, and therefore did not explain the variation in germination responses. Conclusions Variation in germination responses among Calluna populations was consistent with increased temperature requirements for germination towards colder climates, indicating a cold-avoidance germination strategy conditional on the temperature at the seeds' origin. Along a gradient of increasing temperatures this suggests a shift in selection pressures on germination from climatic adversity (i.e. low temperatures and potential frost risk in early or late season) to

Secondary Metabolites Produced during the Germination of Streptomyces coelicolor.

PubMed

Čihák, Matouš; Kameník, Zdeněk; Šmídová, Klára; Bergman, Natalie; Benada, Oldřich; Kofroňová, Olga; Petříčková, Kateřina; Bobek, Jan

2017-01-01

Spore awakening is a series of actions that starts with purely physical processes and continues via the launching of gene expression and metabolic activities, eventually achieving a vegetative phase of growth. In spore-forming microorganisms, the germination process is controlled by intra- and inter-species communication. However, in the Streptomyces clade, which is capable of developing a plethora of valuable compounds, the chemical signals produced during germination have not been systematically studied before. Our previously published data revealed that several secondary metabolite biosynthetic genes are expressed during germination. Therefore, we focus here on the secondary metabolite production during this developmental stage. Using high-performance liquid chromatography-mass spectrometry, we found that the sesquiterpenoid antibiotic albaflavenone, the polyketide germicidin A, and chalcone are produced during germination of the model streptomycete, S. coelicolor . Interestingly, the last two compounds revealed an inhibitory effect on the germination process. The secondary metabolites originating from the early stage of microbial growth may coordinate the development of the producer ( quorum sensing ) and/or play a role in competitive microflora repression ( quorum quenching ) in their nature environments.

Secondary Metabolites Produced during the Germination of Streptomyces coelicolor

PubMed Central

Čihák, Matouš; Kameník, Zdeněk; Šmídová, Klára; Bergman, Natalie; Benada, Oldřich; Kofroňová, Olga; Petříčková, Kateřina; Bobek, Jan

2017-01-01

Spore awakening is a series of actions that starts with purely physical processes and continues via the launching of gene expression and metabolic activities, eventually achieving a vegetative phase of growth. In spore-forming microorganisms, the germination process is controlled by intra- and inter-species communication. However, in the Streptomyces clade, which is capable of developing a plethora of valuable compounds, the chemical signals produced during germination have not been systematically studied before. Our previously published data revealed that several secondary metabolite biosynthetic genes are expressed during germination. Therefore, we focus here on the secondary metabolite production during this developmental stage. Using high-performance liquid chromatography-mass spectrometry, we found that the sesquiterpenoid antibiotic albaflavenone, the polyketide germicidin A, and chalcone are produced during germination of the model streptomycete, S. coelicolor. Interestingly, the last two compounds revealed an inhibitory effect on the germination process. The secondary metabolites originating from the early stage of microbial growth may coordinate the development of the producer (quorum sensing) and/or play a role in competitive microflora repression (quorum quenching) in their nature environments. PMID:29326665

Limited period of graviresponsiveness in germinating spores of Ceratopteris richardii

NASA Technical Reports Server (NTRS)

Edwards, E. S.; Roux, S. J.

1994-01-01

Rhizoids of the fern Ceratopteris richardii Brogn. usually emerge 40 h after germination is initiated by light, and more than 90% of them emerge growing in a downward direction. However, when the spores are germinated on a clinostat, the emerging rhizoids show no preferential orientation. This indicates that under normal 1 g conditions the initial growth direction of rhizoids can be oriented by gravity. If the orientation of the spores is changed 3 h or less after the start of germination, the growth direction of most emerging rhizoids becomes downward relative to the new orientation. However, if the orientation of the spores is changed by 180 degrees 8 h or more after germination is initiated by light, most rhizoids emerge growing upward; i.e., the same direction as if there had been no orientation change. Emerged rhizoids also do not change their direction of growth if their orientation is changed. These results indicate that the growth direction of emerging rhizoids is set by gravity prior to actual emergence, and that the time of full orientation responsiveness is limited to a period ranging from the initiation of germination to about 3-4 h after the start of germination. There is a gravity-oriented nuclear movement beginning at about 13 h after germination, and this movement appears to predict the initial growth direction of rhizoids.

Limited period of graviresponsiveness in germinating spores of Ceratopteris richardii.

PubMed

Edwards, E S; Roux, S J

1994-01-01

Rhizoids of the fern Ceratopteris richardii Brogn. usually emerge 40 h after germination is initiated by light, and more than 90% of them emerge growing in a downward direction. However, when the spores are germinated on a clinostat, the emerging rhizoids show no preferential orientation. This indicates that under normal 1 g conditions the initial growth direction of rhizoids can be oriented by gravity. If the orientation of the spores is changed 3 h or less after the start of germination, the growth direction of most emerging rhizoids becomes downward relative to the new orientation. However, if the orientation of the spores is changed by 180 degrees 8 h or more after germination is initiated by light, most rhizoids emerge growing upward; i.e., the same direction as if there had been no orientation change. Emerged rhizoids also do not change their direction of growth if their orientation is changed. These results indicate that the growth direction of emerging rhizoids is set by gravity prior to actual emergence, and that the time of full orientation responsiveness is limited to a period ranging from the initiation of germination to about 3-4 h after the start of germination. There is a gravity-oriented nuclear movement beginning at about 13 h after germination, and this movement appears to predict the initial growth direction of rhizoids.

In situ investigation of Geobacillus stearothermophilus spore germination and inactivation mechanisms under moderate high pressure.

PubMed

Georget, Erika; Kapoor, Shobhna; Winter, Roland; Reineke, Kai; Song, Youye; Callanan, Michael; Ananta, Edwin; Heinz, Volker; Mathys, Alexander

2014-08-01

Bacterial spores are a major concern for food safety due to their high resistance to conventional preservation hurdles. Innovative hurdles can trigger bacterial spore germination or inactivate them. In this work, Geobacillus stearothermophilus spore high pressure (HP) germination and inactivation mechanisms were investigated by in situ infrared spectroscopy (FT-IR) and fluorometry. G. stearothermophilus spores' inner membrane (IM) was stained with Laurdan fluorescent dye. Time-dependent FT-IR and fluorescence spectra were recorded in situ under pressure at different temperatures. The Laurdan spectrum is affected by the lipid packing and level of hydration, and provided information on the IM state through the Laurdan generalized polarization. Changes in the -CH2 and -CH3 asymmetric stretching bands, characteristic of lipids, and in the amide I' band region, characteristic of proteins' secondary structure elements, enabled evaluation of the impact of HP on endospores lipid and protein structures. These studies were complemented by ex situ analyses (plate counts and microscopy). The methods applied showed high potential to identify germination mechanisms, particularly associated to the IM. Germination up to 3 log10 was achieved at 200 MPa and 55 °C. A molecular-level understanding of these mechanisms is important for the development and validation of multi-hurdle approaches to achieve commercial sterility. Copyright © 2014 Elsevier Ltd. All rights reserved.

Germinated brown rice and its bio-functional compounds.

PubMed

Cho, Dong-Hwa; Lim, Seung-Taik

2016-04-01

Brown rice (BR) contains bran layers and embryo, where a variety of nutritional and biofunctional components, such as dietary fibers, γ-oryzanol, vitamins, and minerals, exist. However, BR is consumed less than white rice because it has an inferior eating texture when cooked. Germination is one of the techniques used to improve the texture of the cooked BR. In addition, it induces numerous changes in the composition and chemical structure of the bioactive components. Moreover, many studies reported that the germination could induce the formation of new bioactive compounds, such as gamma-aminobutyric acid (GABA). The consumption of germinated brown rice (GBR) is increasing in many Asian countries because of its improved eating quality and potential health-promoting functions. However, there is still a lack of studies on the compositional and functional changes of the bioactive components during germination. This review contains recent research findings, especially on the bioactive components in GBR. Copyright © 2015 Elsevier Ltd. All rights reserved.

A role for fruit structure in seed survival and germination of Swartzia langsdorffii Raddi beyond dispersal.

PubMed

Vaz, T A A; Rodrigues-Junior, A G; Davide, A C; Nakamura, A T; Toorop, P E

2018-03-01

Diaspore structure has been hypothesised to play a role in seed viability and/or germination of recalcitrant seeds, especially for Swartzia langsdorffii. Thus, this work aims to (i) investigate the in situ contribution of pericarp and aril on seed viability and germination, and (ii) identify morphoanatomical traits of S. langsdorffii diaspores that allow its desiccation-sensitive seeds to remain viable. The role of the pericarp and aril in seed survival and germination was investigated by placing the whole fruit, whole seeds (arillate seed) and bare seeds (without aril) in soil in the forest understorey, assessing germination, emergence, dead, firm and predated seeds, and water content of pericarps, arils and seeds. Correlation analysis was performed between environmental variables and physiological parameters. Histochemical features of diaspores were also investigated. Pericarp water content fell after several months, while the aril maintained its water content. Seeds did not lose water even without the presence of the pericarp and aril. However, presence of the pericarp promoted seed water content, viability and germination long after dispersal. The embryo had a thickened outer periclinal cell wall. Pericarp and aril are not essential to prevent water loss in seeds, but do help to retain seed moisture, favouring viability maintenance and promoting germination during the rainy season. Morphoanatomical features of seeds are suggested as main factors that reduce water loss. Survival of these desiccation-sensitive seeds upon dispersal during the dry season appears to be facilitated by multiple diaspore features that prevent viability loss. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

α-Xylosidase plays essential roles in xyloglucan remodelling, maintenance of cell wall integrity, and seed germination in Arabidopsis thaliana.

PubMed

Shigeyama, Takuma; Watanabe, Asuka; Tokuchi, Konatsu; Toh, Shigeo; Sakurai, Naoki; Shibuya, Naoto; Kawakami, Naoto

2016-10-01

Regulation and maintenance of cell wall physical properties are crucial for plant growth and environmental response. In the germination process, hypocotyl cell expansion and endosperm weakening are prerequisites for dicot seeds to complete germination. We have identified the Arabidopsis mutant thermoinhibition-resistant germination 1 (trg1), which has reduced seed dormancy and insensitivity to unfavourable conditions for germination owing to a loss-of-function mutation of TRG1/XYL1, which encodes an α-xylosidase. Compared to those of wild type, the elongating stem of trg1 showed significantly lower viscoelasticity, and the fruit epidermal cells were longitudinally shorter and horizontally enlarged. Actively growing tissues of trg1 over-accumulated free xyloglucan oligosaccharides (XGOs), and the seed cell wall had xyloglucan with a greatly reduced molecular weight. These observations suggest that XGOs reduce xyloglucan size by serving as an acceptor in transglycosylation and eventually enhancing cell wall loosening. TRG1/XYL1 gene expression was abundant in growing wild-type organs and tissues but relatively low in cells at most actively elongating part of the tissues, suggesting that α-xylosidase contributes to maintaining the mechanical integrity of the primary cell wall in the growing and pre-growing tissues. In germinating seeds of trg1, expression of genes encoding specific abscisic acid and gibberellin metabolism enzymes was altered in accordance with the aberrant germination phenotype. Thus, cell wall integrity could affect seed germination not only directly through the physical properties of the cell wall but also indirectly through the regulation of hormone gene expression. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

New Insights Into the Roles of NADPH Oxidases in Sexual Development and Ascospore Germination in Sordaria macrospora

PubMed Central

Dirschnabel, Daniela Elisabeth; Nowrousian, Minou; Cano-Domínguez, Nallely; Aguirre, Jesus; Teichert, Ines; Kück, Ulrich

2014-01-01

NADPH oxidase (NOX)-derived reactive oxygen species (ROS) act as signaling determinants that induce different cellular processes. To characterize NOX function during fungal development, we utilized the genetically tractable ascomycete Sordaria macrospora. Genome sequencing of a sterile mutant led us to identify the NADPH oxidase encoding nox1 as a gene required for fruiting body formation, regular hyphal growth, and hyphal fusion. These phenotypes are shared by ∆nor1, lacking the NOX regulator NOR1. Further phenotypic analyses revealed a high correlation between increased ROS production and hyphal fusion deficiencies in ∆nox1 and other sterile mutants. A genome-wide transcriptional profiling analysis of mycelia and isolated protoperithecia from wild type and ∆nox1 revealed that nox1 inactivation affects the expression of genes related to cytoskeleton remodeling, hyphal fusion, metabolism, and mitochondrial respiration. Genetic analysis of ∆nox2, lacking the NADPH oxidase 2 gene, ∆nor1, and transcription factor deletion mutant ∆ste12, revealed a strict melanin-dependent ascospore germination defect, indicating a common genetic pathway for these three genes. We report that gsa3, encoding a G-protein α-subunit, and sac1, encoding cAMP-generating adenylate cyclase, act in a separate pathway during the germination process. The finding that cAMP inhibits ascospore germination in a melanin-dependent manner supports a model in which cAMP inhibits NOX2 activity, thus suggesting a link between both pathways. Our results expand the current knowledge on the role of NOX enzymes in fungal development and provide a frame to define upstream and downstream components of the NOX signaling pathways in fungi. PMID:24407906

Seed germination and sowing options [Chapter 8

Treesearch

Tara Luna; Kim Wilkinson; R. Kasten Dumroese

2009-01-01

Seeds of many native species are challenging to germinate. One important thing a grower can do is learn as much as possible about the life history, ecology, and habitat of the species they wish to grow.What processes do seeds of this species go through in nature? Any observations will be valuable when trying to germinate and grow species that have little or no...

Seed germination and sowing options [Chapter 9

Treesearch

Tara Luna; Kim M. Wilkinson; R. Kasten Dumroese

2014-01-01

Seeds of many native species are challenging to germinate. One important thing a grower can do is to learn as much as possible about the life history, ecology, and habitat of the species he or she wishes to grow to understand the processes seeds from each target species go through in nature. Any observations will be valuable when trying to germinate and grow species...

Investigating the Influence of Karrikins on Seed Germination

ERIC Educational Resources Information Center

de Beer, Josef

2012-01-01

Recent research has identified a karrikin (a butenolide derative) known as 3-methyl-2H-furo[2,3-c]pyran-2-one, formed from burning cellulose, that stimulates seed germination. Here, I present ideas on how to investigate the influence of karrikins on seed germination in the laboratory.

Contrasting germination responses to vegetative canopies experienced in pre- vs. post-dispersal environments.

PubMed

Leverett, Lindsay D; Auge, Gabriela A; Bali, Aman; Donohue, Kathleen

2016-11-01

Seeds adjust their germination based on conditions experienced before and after dispersal. Post-dispersal cues are expected to be more accurate predictors of offspring environments, and thus offspring success, than pre-dispersal cues. Therefore, germination responses to conditions experienced during seed maturation may be expected to be superseded by responses to conditions experienced during seed imbibition. In taxa of disturbed habitats, neighbours frequently reduce the performance of germinants. This leads to the hypotheses that a vegetative canopy will reduce germination in such taxa, and that a vegetative canopy experienced during seed imbibition will over-ride germination responses to a canopy experienced during seed maturation, since it is a more proximal cue of immediate competition. These hypotheses were tested here in Arabidopsis thaliana METHODS: Seeds were matured under a simulated canopy (green filter) or white light. Fresh (dormant) seeds were imbibed in the dark, white light or canopy at two temperatures (10 or 22 °C), and germination proportions were recorded. Germination was also recorded in after-ripened (less dormant) seeds that were induced into secondary dormancy and imbibed in the dark at each temperature, either with or without brief exposure to red and far-red light. Unexpectedly, a maturation canopy expanded the conditions that elicited germination, even as seeds lost and regained dormancy. In contrast, an imbibition canopy impeded or had no effect on germination. Maturation under a canopy did not modify germination responses to red and far-red light. Seed maturation under a canopy masked genetic variation in germination. The results challenge the hypothesis that offspring will respond more strongly to their own environment than to that of their parents. The observed relaxation of germination requirements caused by a maturation canopy could be maladaptive for offspring by disrupting germination responses to light cues after dispersal

Contrasting germination responses to vegetative canopies experienced in pre- vs. post-dispersal environments

PubMed Central

Leverett, Lindsay D.; Auge, Gabriela A.; Bali, Aman; Donohue, Kathleen

2016-01-01

Background Seeds adjust their germination based on conditions experienced before and after dispersal. Post-dispersal cues are expected to be more accurate predictors of offspring environments, and thus offspring success, than pre-dispersal cues. Therefore, germination responses to conditions experienced during seed maturation may be expected to be superseded by responses to conditions experienced during seed imbibition. In taxa of disturbed habitats, neighbours frequently reduce the performance of germinants. This leads to the hypotheses that a vegetative canopy will reduce germination in such taxa, and that a vegetative canopy experienced during seed imbibition will over-ride germination responses to a canopy experienced during seed maturation, since it is a more proximal cue of immediate competition. These hypotheses were tested here in Arabidopsis thaliana. Methods Seeds were matured under a simulated canopy (green filter) or white light. Fresh (dormant) seeds were imbibed in the dark, white light or canopy at two temperatures (10 or 22 °C), and germination proportions were recorded. Germination was also recorded in after-ripened (less dormant) seeds that were induced into secondary dormancy and imbibed in the dark at each temperature, either with or without brief exposure to red and far-red light. Key Results Unexpectedly, a maturation canopy expanded the conditions that elicited germination, even as seeds lost and regained dormancy. In contrast, an imbibition canopy impeded or had no effect on germination. Maturation under a canopy did not modify germination responses to red and far-red light. Seed maturation under a canopy masked genetic variation in germination. Conclusions The results challenge the hypothesis that offspring will respond more strongly to their own environment than to that of their parents. The observed relaxation of germination requirements caused by a maturation canopy could be maladaptive for offspring by disrupting germination responses

Exploration of factors affecting the onset and maturation course of follicular lymphoma through simulations of the germinal center.

PubMed

Fenwick, Michael K; Escobedo, Fernando A

2009-08-01

Genetic mutations frequently observed in human follicular lymphoma (FL) B-cells result in aberrant expression of the anti-apoptotic protein bcl-2 and surface immunoglobulins (Igs) which display one or more novel variable (V) region N-glycosylation motifs. In the present study, we develop a simulation model of the germinal center (GC) to explore how these mutations might influence the emergence and clonal expansion of key mutants which provoke FL development. The simulations employ a stochastic method for calculating the cellular dynamics, which incorporates actual IgV region sequences and a simplified hypermutation scheme. We first bring our simulations into agreement with experimental data for well-characterized normal and bcl-2(+) anti-hapten GC responses in mice to provide a model for understanding how bcl-2 expression leads to permissive selection and memory cell differentiation of weakly competitive B-cells. However, as bcl-2 expression in the GC alone is thought to be insufficient for FL development, we next monitor simulated IgV region mutations to determine the emergence times of key mutants displaying aberrant N-glycosylation motifs recurrently observed in human FL IgV regions. Simulations of 26 germline V(H) gene segments indicate that particular IgV regions have a dynamical selective advantage by virtue of the speed with which one or more of their key sites can generate N-glycosylation motifs upon hypermutation. Separate calculations attribute the high occurrence frequency of such IgV regions in FL to an ability to produce key mutants at a fast enough rate to overcome stochastic processes in the GC that hinder clonal expansion. Altogether, these simulations characterize three pathways for FL maturation through positively selected N-glycosylations, namely, via one of two key sites within germline V(H) region gene segments, or via a site in the third heavy chain complementarity-determining region (CDR-H3) that is generated from VDJ recombination.

New amino acid germinants for spores of the enterotoxigenic Clostridium perfringens type A isolates.

PubMed

Udompijitkul, Pathima; Alnoman, Maryam; Banawas, Saeed; Paredes-Sabja, Daniel; Sarker, Mahfuzur R

2014-12-01

Clostridium perfringens spore germination plays a critical role in the pathogenesis of C. perfringens-associated food poisoning (FP) and non-food-borne (NFB) gastrointestinal diseases. Germination is initiated when bacterial spores sense specific nutrient germinants (such as amino acids) through germinant receptors (GRs). In this study, we aimed to identify and characterize amino acid germinants for spores of enterotoxigenic C. perfringens type A. The polar, uncharged amino acids at pH 6.0 efficiently induced germination of C. perfringens spores; L-asparagine, L-cysteine, L-serine, and L-threonine triggered germination of spores of most FP and NFB isolates; whereas, L-glutamine was a unique germinant for FP spores. For cysteine- or glutamine-induced germination, gerKC spores (spores of a gerKC mutant derivative of FP strain SM101) germinated to a significantly lower extent and released less DPA than wild type spores; however, a less defective germination phenotype was observed in gerAA or gerKB spores. The germination defects in gerKC spores were partially restored by complementing the gerKC mutant with a recombinant plasmid carrying wild-type gerKA-KC, indicating that GerKC is an essential GR protein. The gerKA, gerKC, and gerKB spores germinated significantly slower with L-serine and L-threonine than their parental strain, suggesting the requirement for these GR proteins for normal germination of C. perfringens spores. In summary, these results indicate that the polar, uncharged amino acids at pH 6.0 are effective germinants for spores of C. perfringens type A and that GerKC is the main GR protein for germination of spores of FP strain SM101 with L-cysteine, L-glutamine, and L-asparagine. Copyright © 2014 Elsevier Ltd. All rights reserved.

He-Ne laser-induced changes in germination, thermodynamic parameters, internal energy, enzyme activities and physiological attributes of wheat during germination and early growth

NASA Astrophysics Data System (ADS)

Jamil, Yasir; Perveen, Rashida; Ashraf, Muhammad; Ali, Qasim; Iqbal, Munawar; Ahmad, Muhammad Raza

2013-04-01

Using low power continuous wave He-Ne laser irradiation of seeds, the germination characteristics, thermodynamic changes and enzyme activities as well as changes in morphological attributes were explored for wheat (Triticum aestivum L. cv. S-24) cultivar. The changes in thermodynamic properties such as change in enthalpy (ΔH), entropy generation [(ΔSe)], entropy flux [(ΔSc)], entropy generation ratio [(ΔS)e/Δt], and entropy flux ratio [(ΔS)c/Δt] showed significant (P < 0.05) changes at an energy level of 500 mJ. The germination energy (GE), germination percentage (G%), germination index (GI) as well as α-amylase and protease activities was also found to be higher at 500 mJ, while the mean emergence time (MET) and time for 50% germination (E50) decreased for 300 mJ irradiance. The internal energy of the seeds increased significantly at all laser energy levels, but was highest for 500 mJ 72 h after sowing. The enzyme activities increased up to 24 h after sowing and then declined. The activities of α-amylase and protease were found to be positively correlated with the plant physiological attributes. These results indicate that low power continuous wave He-Ne laser (632 nm) treatment has considerable biological effects on seed metabolism during germination as well as on later vegetative growth.

Release of Reactive Oxygen Intermediates (Superoxide Radicals, Hydrogen Peroxide, and Hydroxyl Radicals) and Peroxidase in Germinating Radish Seeds Controlled by Light, Gibberellin, and Abscisic Acid1

PubMed Central

Schopfer, Peter; Plachy, Claudia; Frahry, Gitta

2001-01-01

Germination of radish (Raphanus sativus cv Eterna) seeds can be inhibited by far-red light (high-irradiance reaction of phytochrome) or abscisic acid (ABA). Gibberellic acid (GA3) restores full germination under far-red light. This experimental system was used to investigate the release of reactive oxygen intermediates (ROI) by seed coats and embryos during germination, utilizing the apoplastic oxidation of 2′,7′-dichlorofluorescin to fluorescent 2′,7′-dichlorofluorescein as an in vivo assay. Germination in darkness is accompanied by a steep rise in ROI release originating from the seed coat (living aleurone layer) as well as the embryo. At the same time as the inhibition of germination, far-red light and ABA inhibit ROI release in both seed parts and GA3 reverses this inhibition when initiating germination under far-red light. During the later stage of germination the seed coat also releases peroxidase with a time course affected by far-red light, ABA, and GA3. The participation of superoxide radicals, hydrogen peroxide, and hydroxyl radicals in ROI metabolism was demonstrated with specific in vivo assays. ROI production by germinating seeds represents an active, developmentally controlled physiological function, presumably for protecting the emerging seedling against attack by pathogens. PMID:11299341

[Eco-physiological studies on desert plants : V. Influence of soaking and redrying on the germination of Zygophyllum coccineum seeds and the possible contribution of an inhibitor to the effect].

PubMed

Batanouny, K H; Ziegler, H

1971-06-01

1. The rate and percentage of germination of soaked and redried seeds are higher than those of untreated seeds. The promoting effect of soaking and redryring of seeds on germination increases with the duration of soaking. Seeds that germinated during soaking are unable to tolerate drying. 2. Exposure of the seeds to light after the first 8 hours of soaking inhibits germination of the seeds after drying. 3. Washing the seeds with water has no effect on germination in the dark at 25°C, while it promotes germination in light at 25°C and in the dark at 10°C. 4. The leachate of Zygophyllum coccineum seeds has no significant effect on the dark germination of these seeds. On the other hand, it inhibits the light germination. Germination of Lepidium sativum seeds is not affected by the leachate of Zygophyllum seeds, either in the dark or in light. 5. When the washed seeds of Zygophyllum coccineum are germinated, their radicles are longer and the hypocotyls shorter than in the controls. The leachate promotes hypocotyl growth and inhibits that of the radicle. 6. A hypothesis is suggested to interpret the results based on the assumed interaction between seeds, light and an inhibitor.

Potential impacts of CO2 leakage from the CCS sites on seed germination and soil microbial enzyme activities

NASA Astrophysics Data System (ADS)

Wenmei, H.; Yoo, G.; Kim, Y.; Moonis, M.

2015-12-01

To ensure the safety of carbon capture and storage (CCS) technology, it is essential to assess the impacts of potential CO2 leakage on the soil and ecosystem. The changes in soil environment due to the CO2 leakage might have an enormous effect on the plant growth. As a preliminary study, we conducted a research focusing on the germination process because it is known to be especially sensitive to the environmental change. The objective of this study is to investigate the impacts of high soil CO2 concentration on the germination of different species. A laboratory experiment was designed to investigate the effect of high soil CO2 concentration on germination rate and soil physicochemical/microbial parameters. Cabbage, corn, bean, and wheat were selected for this study. The concentrations of the injected CO2 treatments were 10%, 30%, 60% and 100%, and the actual soil CO2 concentration ranged from 3.6% to 53.2%. Two types of controls were employed: the one connected with ambient air tank and the other connected with nothing. The final germination rates of four crops were not different between the controls and 10% treatment, but the delay of germination was observed in cabbage, corn, and bean. At 30% treatment, the germination rates of cabbage, corn and bean were 38%, while that of wheat was 78%. No seed was germinated at 60% and 100% treatments. After the incubation, soil pH decreased from 6.0 in the controls to 5.6 in the 100% treatment. The contents of soil total C and total N were not different among treatments. Activities of microbial fluorescein diacetate hydrolysis were not different among treatments for all plants. Five kinds of soil extracellular enzyme activities were not affected by the CO2 treatments. Our results suggest that: 1) Soil CO2 concentration at 3-4% did not inhibit germination of four crops. 2) Wheat is most resistant to high soil CO2 concentration in this study. 3) Soil microbial parameters were more tolerant during the short term injection.

Effect of Different Germination Conditions on Antioxidative Properties and Bioactive Compounds of Germinated Brown Rice

PubMed Central

Lin, You-Tung; Pao, Cheng-Cheng; Wu, Shwu-Tzy; Chang, Chi-Yue

2015-01-01

This study investigates antioxidative activity and bioactive compounds of ungerminated brown rice (UBR) and germinated brown rice (GBR). We used two rice cultivars (Oryza sativa L.), Taiwan Japonica 9 (TJ-9) and Taichung Indica 10 (TCI-10), as the materials in our experiments. The conditions for inducing germination are soaking time in water 24, 48, or 72 h; temperature 26 or 36°C; incubation in light or darkness; and open or closed vessels, in which the antioxidative activities and bioactive compounds of GBR were determined. We found that, in order to maximize antioxidative activity and bioactive compounds, germination should be under higher temperature (36°C), long soaking time (72 h), darkness, and closed vessel. GBR contains much higher levels of antioxidative activity and bioactive compounds than ungerminated brown rice (UBR). We found a strong correlation between antioxidative activities (DPPH radical scavenging ability, reducing power, and Trolox equivalent antioxidant capacity) and bioactive compounds (γ-oryzanols, tocopherol, and tocotrienol). Higher temperature (36°C) is also conducive to the production of GABA in GBR. These results are considered very useful research references for the development of future functional foods and additives. PMID:25861637

Cytological and Proteomic Analyses of Osmunda cinnamomea Germinating Spores Reveal Characteristics of Fern Spore Germination and Rhizoid Tip Growth.

PubMed

Suo, Jinwei; Zhao, Qi; Zhang, Zhengxiu; Chen, Sixue; Cao, Jian'guo; Liu, Guanjun; Wei, Xing; Wang, Tai; Yang, Chuanping; Dai, Shaojun

2015-09-01

Fern spore is a good single-cell model for studying the sophisticated molecular networks in asymmetric cell division, differentiation, and polar growth. Osmunda cinnamomea L. var. asiatica is one of the oldest fern species with typical separate-growing trophophyll and sporophyll. The chlorophyllous spores generated from sporophyll can germinate without dormancy. In this study, the spore ultrastructure, antioxidant enzyme activities, as well as protein and gene expression patterns were analyzed in the course of spore germination at five typical stages (i.e. mature spores, rehydrated spores, double-celled spores, germinated spores, and spores with protonemal cells). Proteomic analysis revealed 113 differentially expressed proteins, which were mainly involved in photosynthesis, reserve mobilization, energy supplying, protein synthesis and turnover, reactive oxygen species scavenging, signaling, and cell structure modulation. The presence of multiple proteoforms of 25 differentially expressed proteins implies that post-translational modification may play important roles in spore germination. The dynamic patterns of proteins and their encoding genes exhibited specific characteristics in the processes of cell division and rhizoid tip growth, which include heterotrophic and autotrophic metabolisms, de novo protein synthesis and active protein turnover, reactive oxygen species and hormone (brassinosteroid and ethylene) signaling, and vesicle trafficking and cytoskeleton dynamic. In addition, the function skew of proteins in fern spores highlights the unique and common mechanisms when compared with evolutionarily divergent spermatophyte pollen. These findings provide an improved understanding of the typical single-celled asymmetric division and polar growth during fern spore germination. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Reassessment of an Arabidopsis cell wall invertase inhibitor AtCIF1 reveals its role in seed germination and early seedling growth.

PubMed

Su, Tao; Wolf, Sebastian; Han, Mei; Zhao, Hongbo; Wei, Hongbin; Greiner, Steffen; Rausch, Thomas

2016-01-01

In higher plants, cell wall invertase (CWI) and vacuolar invertase (VI) are recognized as essential players in sugar metabolism and sugar signaling, thereby affecting source-sink interactions, plant development and responses to environmental cues. CWI and VI expression levels are transcriptionally controlled; however, both enzymes are also subject to posttranslational control by invertase inhibitor proteins. The physiological significances of inhibitor proteins during seed germination and early seedling development are not yet fully understood. Here, we demonstrate that the inhibitor isoform AtCIF1 impacted on seed germination and early seedling growth in Arabidopsis. The primary target of AtCIF1 was shown to be localized to the apoplast after expressing an AtCIF1 YFP-fusion construct in tobacco epidermis and transgenic Arabidopsis root. The analysis of expression patterns showed that AtCWI1 was co-expressed spatiotemporally with AtCIF1 within the early germinating seeds. Seed germination was observed to be accelerated independently of exogenous abscisic acid (ABA) in the AtCIF1 loss-of-function mutant cif1-1. This effect coincided with a drastic increase of CWI activity in cif1-1 mutant seeds by 24 h after the onset of germination, both in vitro and in planta. Accordingly, quantification of sugar content showed that hexose levels were significantly boosted in germinating seeds of the cif1-1 mutant. Further investigation of AtCIF1 overexpressors in Arabidopsis revealed a markedly suppressed CWI activity as well as delayed seed germination. Thus, we conclude that the posttranslational modulation of CWI activity by AtCIF1 helps to orchestrate seed germination and early seedling growth via fine-tuning sucrose hydrolysis and, possibly, sugar signaling.

Age Learning Factors Affecting Pilot Education.

ERIC Educational Resources Information Center

Torbert, Brison

This document, intended for pilot education and flight safety specialists, consists chiefly of a review of the literature on physiological factors that affect pilot education and an examination of environmental factors that should be scrutinized in order to improve the effectiveness of aviation learning facilities. The physiological factors…

Dispersal and Germination Patterns of Monterey Spineflower at Fort Ord Natural Reserve.

NASA Astrophysics Data System (ADS)

Chaudhry, Z.

2014-12-01

Some species are rare because they are restricted to certain habitats and/or have small population sizes. Monterey spineflower, a federally listed threatened annual plant, is found in open sandy regions of the California coast, in chaparral vegetation around the Monterey Bay. A model based on previous research suggests that the Monterey spineflower population at Fort Ord Natural Reserve should be rapidly increasing, but it is not. This suggests that the model may be using data that overestimates the percentage of spineflower seeds that successfully germinate. I tested three hypotheses to determine the cause of the difference in population sizes between the predicted model and the field results. First, I predicted that the spineflower seeds are blown by the wind into shrubs such as manzanita, and are unable to germinate due to the lack of a suitable environment. I tested this in two ways. A field experiment showed that seeds are easily blow by wind. Next, I took soil cores and found spineflower seeds within the manzanita shrubs. Secondly, I predicted that the germination rate used by the model (90%) was too high. However, my germination experiments did not support this hypothesis because 91% of new seeds successfully germinated. Lastly, I predicted that the newer seeds are more viable than older seeds and therefore have a higher chance of successfully germinating. After germinating seeds in a controlled environment I observed that the seeds from 2014 had a higher number of successfully germinated seeds compared to the number of successfully germinated seeds from 1995 (91% vs 33%). I conclude that the loss of seeds due to wind decreases germination expectancies and older seeds are less viable than new seeds. Therefore, Monterey spineflower is a rare plant because environmental barriers hinder seeds from dispersing to a suitable habitat and successfully germinating while seeds lose viability as they age.

Terpenoid trans-caryophyllene inhibits weed germination and induces plant water status alteration and oxidative damage in adult Arabidopsis.

PubMed

Araniti, F; Sánchez-Moreiras, A M; Graña, E; Reigosa, M J; Abenavoli, M R

2017-01-01

trans-Caryophyllene (TC) is a sesquiterpene commonly found as volatile component in many different aromatic plants. Although the phytotoxic effects of trans-caryophyllene on seedling growth are relatively explored, not many information is available regarding the phytotoxicity of this sesquiterpenes on weed germination and on adult plants. The phytotoxic potential of TC was assayed in vitro on weed germination and seedling growth to validate its phytotoxic potential on weed species. Moreover, it was assayed on the metabolism of Arabidopsis thaliana adult plants, through two different application ways, spraying and watering, in order to establish the primary affected organ and to deal with the unknown mobility of the compound. The results clearly indicated that TC inhibited both seed germination and root growth, as demonstrated by comparison of the ED50 values. Moreover, although trans-caryophyllene-sprayed adult Arabidopsis plants did not show any effect, trans-caryophyllene-watered plants became strongly affected. The results suggested that root uptake was a key step for the effectiveness of this natural compound and its phytotoxicity on adult plants was mainly due to the alteration of plant water status accompanied by oxidative damage. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Complexes of D-type cyclins with CDKs during maize germination

PubMed Central

Vázquez-Ramos, Jorge M.

2013-01-01

The importance of cell proliferation in plant growth and development has been well documented. The majority of studies on basic cell cycle mechanisms in plants have been at the level of gene expression and much less knowledge has accumulated in terms of protein interactions and activation. Two key proteins, cyclins and cyclin-dependent kinases (CDKs) are fundamental for cell cycle regulation and advancement. Our aim has been to understand the role of D-type cyclins and type A and B CDKs in the cell cycle taking place during a developmental process such as maize seed germination. Results indicate that three maize D-type cyclins—D2;2, D4;2, and D5;3—(G1-S cyclins by definition) bind and activate two different types of CDK—A and B1;1—in a differential way during germination. Whereas CDKA–D-type cyclin complexes are more active at early germination times than at later times, it was surprising to observe that CDKB1;1, a supposedly G2-M kinase, bound in a differential way to all D-type cyclins tested during germination. Binding to cyclin D2;2 was detectable at all germination times, forming a complex with kinase activity, whereas binding to D4;2 and D5;3 was more variable; in particular, D5;3 was only detected at late germination times. Results are discussed in terms of cell cycle advancement and its importance for seed germination. PMID:24127516

Association analysis of salt tolerance in cowpea (Vigna unguiculata (L.) Walp) at germination and seedling stages

USDA-ARS?s Scientific Manuscript database

Cowpea is one of the most important cultivated legumes in Africa. The worldwide annual production in cowpea dry seed is 5.4 million metric tons. However, cowpea is unfavorably affected by salinity stress at germination and seedling stages, which is exacerbated by the effects of climate change. The l...

Quality evaluation of physical properties, antinutritional factors, and antioxidant activity of bread fortified with germinated horse gram (Dolichus uniflorus) flour.

PubMed

Moktan, Karishma; Ojha, Pravin

2016-09-01

Horse gram was germinated at 90% RH at 25°C for 72 h after 24 h soaking and then grinded to pass through 150 μm mesh size screens. The germination of horse gram result in increased protein, fiber, total polyphenol content, and antioxidant activity of horse gram flour whereas fat, ash, carbohydrate, iron, calcium, tannin, phytate, and oxalate were reduced due to germination. Bread was prepared by the incorporation of (2%, 4%, 6%, and 8%) germinated horse gram flour (GHF) by a straight dough method. The loaf volume and specific volume decreased with an increased use of percentage of GHF. The sensory evaluation revealed that the incorporation of GHF up to 6% was acceptable. The protein (% db), fiber (% db), ash (% db), iron (mg/100 g), calcium (mg/100 g), tannin (mg/g), phytate (mg/g), oxalate (mg/g), total polyphenol content (GAE/g), and antioxidant activity (DPPH % inhibition) was found to be 9.08 ± 0.01, 1.23 ± 0.15, 1.36 ± 0.11, 4.07 ± 0.03, 128 ± 0.26, 2.06 ± 0.15, 2.46 ± 0.15, 0.7 ± 0.1, 12.44 ± 0.40, and 31.13 ± 0.25, respectively, in 6% GHF incorporated bread. The research concludes that 6% GHF incorporation in bread enhance the polyphenol content and antioxidant properties.

[Effects of illumination and seed-soaking reagent on seed germination of Solanum nigrum].

PubMed

Yang, Chuan-Jie; Wei, Shu-He; Zhou, Qi-Xing; Hu, Ya-Hu; Niu, Rong-Cheng

2009-05-01

To explore a rapid seed germination method for hyperaccumulator Solanum nigrum, a germination experiment with different illumination and seed-soaking treatments was conducted in constant temperature box and greenhouse, with filter as burgeon base. Under illumination, the germination rate was about 5 times high of that without illumination (P < 0.05), indicating that illumination was one of the prerequisites for the seed germination of S. nigrum. All test seed-soaking reagents could significantly improve the germination rate of S. nigrum (P < 0.05), with the best effect of H2O2. The seeds treated with H2O2 had the shortest germination time. The germination rate of seeds soaked but without cleaning was 2-3 times as high as that of seeds soaked and cleaned with water.

Proteomic Dissection of Seed Germination and Seedling Establishment in Brassica napus

PubMed Central

Gu, Jianwei; Chao, Hongbo; Gan, Lu; Guo, Liangxing; Zhang, Kai; Li, Yonghong; Wang, Hao; Raboanatahiry, Nadia; Li, Maoteng

2016-01-01

The success of seed germination and establishment of a normal seedling are key determinants of plant species propagation. At present, only a few studies have focused on the genetic control of seed germination by using a proteomic approach in Brassica napus. In the present study, the protein expression pattern of seed germination was investigated using differential fluorescence two-dimensional gel electrophoresis in B. napus. One hundred and thirteen differentially expressed proteins (DEPs) that were mainly involved in storage (23.4%), energy metabolism (18.9%), protein metabolism (16.2%), defense/disease (12.6%), seed maturation (11.7%), carbohydrate metabolism (4.5%), lipid metabolism (4.5%), amino acids metabolism (3.6%), cell growth/division (3.6%), and some unclear functions (2.7%) were observed by proteomic analysis. Seventeen genes corresponding to 11 DEPs were identified within or near the associated linkage disequilibrium regions related to seed germination and vigor quantitative traits reported in B. napus in previous studies. The expression pattern of proteins showed that heterotrophic metabolism could be activated in the process of seed germination and that the onset of defense mechanisms might start during seed germination. These findings will help generate a more in-depth understanding of the mobilization of seed storage reserves and regulation mechanisms of the germination process in B. napus. PMID:27822216

Arabidopsis DET1 degrades HFR1 but stabilizes PIF1 to precisely regulate seed germination

PubMed Central

Shi, Hui; Wang, Xin; Mo, Xiaorong; Tang, Chao; Zhong, Shangwei; Deng, Xing Wang

2015-01-01

Seed is an essential propagation organ and a critical strategy adopted by terrestrial flowering plants to colonize the land. The ability of seeds to accurately respond to light is vital for plant survival. However, the underlying mechanism is largely unknown. In this study, we reveal a circuit of triple feed-forward loops adopted by Arabidopsis seeds to exclusively repress germination in dark conditions and precisely initiate germination under diverse light conditions. We identify that de-etiolated 1 (DET1), an evolutionarily conserved protein, is a central repressor of light-induced seed germination. Genetic analysis demonstrates that DET1 functions upstream of long hypocotyl in far-red 1 (HFR1) and phytochrome interacting factor 1 (PIF1), the key positive and negative transcription regulators in seed germination. We further find that DET1 and constitutive photomorphogenic 10 (COP10) target HFR1 for protein degradation by assembling a COP10–DET1–damaged DNA binding protein 1–cullin4 E3 ligase complex. Moreover, DET1 and COP10 directly interact with and promote the protein stability of PIF1. Computational modeling reveals that phytochrome B (phyB)–DET1–HFR1–PIF1 and phyB–DET1–Protease–PIF1 are new signaling pathways, independent of the previously identified phyB-PIF1 pathway, respectively mediating the rapid and time-lapse responses to light irradiation. The model-simulated results are highly consistent with their experimental validations, suggesting that our mathematical model captures the essence of Arabidopsis seed germination networks. Taken together, this study provides a comprehensive molecular framework for light-regulated seed germination, improving our understanding of how plants respond to changeable environments. PMID:25775589

Polarity of Spore Germination in Funaria hygrometrica Hedw.

NASA Astrophysics Data System (ADS)

Pundyak, O. I.; Demkiv, O. T.; Khorkavtsiv, O. Ya; Bagrii, B. B.

It is shown that in darkness the spores of moss Funaria hygrometrica Hedw. germinated polarly under the influence of gravity. At the beginning the rhizoids appeared. They grew downwards. Then future chloronematical stolons started to form a germination spore. Usually, they grew upwards. Clinorotation or horizontal placing of Petry dishes could discoordinate such a gravisensitivity.

Environmental Factors Affecting Preschoolers' Motor Development

ERIC Educational Resources Information Center

Venetsanou, Fotini; Kambas, Antonis

2010-01-01

The process of development occurs according to the pattern established by the genetic potential and also by the influence of environmental factors. The aim of the present study was to focus on the main environmental factors affecting motor development. The review of the literature revealed that family features, such as socioeconomic status,…

The structural requirements for immunoglobulin aggregates to localize in germinal centres.

PubMed Central

Embling, P H; Evans, H; Guttierez, C; Holborow, E J; Johns, P; Johnson, P M; Papamichail, M; Stanworth, D R

1978-01-01

The capacity of non-heat-aggregated monoclonal human immunoglobulins of different classes, to localize in murine splenic germinal centres within 24 h of intravenous injection has been investigated. It has been shown that at least trimerization of polyclonal IgG must occur before any germinal centre trapping is manifest. Studies of complement fixation by these IgG preparations in vivo, together with studies of the germinal centre trapping of various monoclonal immunoglobulins, have indicated that the sole structural requirement for germinal centre localization of immunoglobulin aggregates is the ability to fix complement. Results suggest that immunoglobulin aggregates are transported to germinal centres via membrane C3 receptors of mobile cells, and then are released with loss of complement to become fixed to dendritic macrophages by a separate mechanism. PMID:363602

Changes of the phenolic compounds and antioxidant activities in germinated adlay seeds.

PubMed

Xu, Lei; Wang, Pei; Ali, Barkat; Yang, Na; Chen, Yisheng; Wu, Fengfeng; Xu, Xueming

2017-09-01

Over the years, germinated adlay products have been used as both food source and folk medicine. This study investigated the changes of total phenolic content (TPC), total flavonoid content (TFC), antioxidant activities, and phenolic acid profiles of adlay seed during germination. Results revealed that phenolic compounds and antioxidant activities varied with the germination stages. Germination significantly increased the free form phenolic and flavonoid contents by 112.5% and 168.3%, respectively. However, both of the bound form phenolic and flavonoid contents significantly decreased after germination. Phenolic acid compositions were quantified via HPLC analysis, and the levels of vanillic, p-coumaric, caffeic, hydroxybenzoic and protocatechuic acids in the free phenolic extracts were found to be significantly increased. The improvement of the free and total phenolic and flavonoid contents by the germination process led to a significant enhancement of the antioxidant activities (evaluated by the ABTS, FRAP and ORAC assays). The TPC showed the highest correlation with ORAC values (r = 0.9979). Germinated adlay had higher free and total phenolic and flavonoid contents, and antioxidant activities than ungerminated adlay. This study indicates that germinated adlay could be a promising functional food, more suitable for human consumption. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Release of Esterase Following Germination of Lettuce Seed (Lactuca sativa L.)

PubMed Central

Chandra, G. Ram; Toole, Vivian K.

1977-01-01

Light-insensitive lettuce seeds, Lactuca sativa L. cv. Great Lakes, release esterases for a period following radicle protrusion. Very little or no enzymes are released prior to 24 hours or after 48 hours of germination. As compared to intact seeds, half-seeds readily release esterases and the release is not affected by far red irradiation. Bulk of the released esterases are derived from the endosperm tissue and presumably exists in the intact seed as a component of the extraembryonic fluid. PMID:16659992

A direct observation technique for evaluating sclerotium germination by Macrophomina phaseolina and effects of biocontrol materials on survival of sclerotia in soil.

PubMed

Pratt, Robert G

2006-08-01

Germination of sclerotia of Macrophomina phaseolina was quantified by direct microscopic observation following application of experimental treatments in vitro and incubation of sclerotia in soil. To assay germination, pieces of agar containing sclerotia were macerated in dilute, liquid cornmeal agar on glass slides; thinly spread; and incubated in a saturated atmosphere for 18-22 h. Germinated sclerotia then were identified by morphological features of germ hyphae. Frequencies of germination were similar in three dilute agar media. Germination was not affected by air-drying sclerotia for 2 weeks, but it was significantly reduced after 4 weeks and greatly reduced or eliminated after 6 or 8 weeks. Survival of sclerotia for 14 days in soil was greatest at 50, 75, and 100% moisture-holding capacity, less at 0 and 25%, and least at 125% (flooded soil). Incorporation of ground poultry litter into soil at 5% by weight reduced survival of sclerotia after 13 days, and incorporation of litter at 10% nearly eliminated it. These results indicate that the direct-observation technique may be used to evaluate animal wastes and other agricultural byproducts for biocontrol activity against sclerotia of M. phaseolina in soil.

Impact of electromagnetic microwaves on the germination of spores of Streptomyces xanthochromogenes in a peat soil and in a liquid nutrient medium

NASA Astrophysics Data System (ADS)

Komarova, A. S.; Likhacheva, A. A.; Lapygina, E. V.; Maksimova, I. A.; Pozdnyakov, A. I.

2010-01-01

The impact of microwaves on the germination of spores of Streptomyces xanthochromogenes in a liquid nutrient medium and in a peat soil was studied. The treatment of inoculums with microwave radiation affected the development of the microorganisms from the stage of spore germination to the stage of the formation of microcolonies of actinomycetes upon the spore cultivation in the liquid medium. Typical hypnum-herbaceous peat was used to study the rate of germination of the actinomycetal spores in soil. The study of the dynamics of the Streptomyces xanthochromogenes population in the control soil (without treatment with microwaves) showed that the most active development of the culture took place in the soil moistened to 60% of the maximum water capacity. When the soil was moistened to the minimum adsorption capacity, the streptomyces did not complete their full cycle of development. The stimulation of the spore germination and mycelium growth with microwaves in the soil medium required a longer period in comparison with that for the liquid medium. The stimulation of the spore germination was observed in the liquid nutrient medium in the case of 30-s treatment and in the soil in the case of 60-s treatment.

[A comparative study on seed germination of 15 grass species in Keeqin Sandyland].

PubMed

Liu, Zhimin; Li, Xuehua; Li, Rongping; Jiang, Deming; Cao, Chengyou

2003-09-01

A laboratory study was made on the germination characteristics of freshly-collected seeds of grass species at the Wulanaodu area of Keeqin Sandyland in Eastern Inner-Mongolia. Of the 15 species examined, 8 species including Clinelymus dahuricus, Cleistogenes squarrosa, Pappophorum boreale, Spodiopogon sibiricus, Phragmites communis, Chloris virgata, Arundinella hirta, Pennisetum alopecuroides had a germination rate of over 80%, but 4 species including Echinochloa hispidula, Hemarthria compressa, Tragus berteronianus and Setaria viridis had a value of less than 10%. Spodiopogon sibiricus, Eragrostis pilosa, Phragmites communis, Chloris virgata, Clinelymus dahuricus, Pappophorum boreale, Digitaria cilliaris and Cleistogenes squrrosa began to germinate within 1-3 days after the test began, while Setaria viridis, Tragus berteronianus and Hemarthria compressa failed to germinate in a period of more than 10 days. For the species such as Digitaria cilliaris, Echinochloa hispidula, Phragmites communis, Eragrostis pilosa and Spodiopogon sibiricus, their germination period was less than 10 days, while Clinelymus dahuricus and Pappophorum boreale had a germination period of more than 20 days. The days required for half the final germination rate to be reached were: 2 days for Chloris virgata, 3 days for Phragmites communis, 4 days for Spodiopogon sibiricus, 5 days for Clinelymus dahuricus and Cleistogenes squarrosa, 7 days for Arundinella hirta and Pappophorum boreale, and 10 days for Pennisetum alopecuriodes. Compared with the Sheffield region in Britain, the Wulanaodu area of Kerqin Sandyland had a higher proportion of annul grasses with a low germination rate and a longer germination period, and the perennial grasses at the Wulanaodu area had an approximately same germination rate, but a longer germination period. During germination, ruderals showed the potential for risk-sharring, and thus, they had a relatively higher disturbance-resistance capacity.

Soil reaction and germination of Douglas-fir seed.

Treesearch

Robert F. Tarrant

1954-01-01

Wood ash and its accompanying alkalinity have sometimes been cited as being harmful to germination of tree seed on slash-burned forest land. Unasylva, the United Nations forestry publication, recently carried a report of research in British Columbia on the effect of slash burning on germination and initial survival of lodgepole pine and Douglas-fir. One finding was...

Proteomic analysis during of spore germination of Moniliophthora perniciosa, the causal agent of witches' broom disease in cacao.

PubMed

Mares, Joise Hander; Gramacho, Karina Peres; Santos, Everton Cruz; da Silva Santiago, André; Santana, Juliano Oliveira; de Sousa, Aurizângela Oliveira; Alvim, Fátima Cerqueira; Pirovani, Carlos Priminho

2017-08-17

Moniliophthora perniciosa is a phytopathogenic fungus responsible for witches' broom disease of cacao trees (Theobroma cacao L.). Understanding the molecular events during germination of the pathogen may enable the development of strategies for disease control in these economically important plants. In this study, we determined a comparative proteomic profile of M. perniciosa basidiospores during germination by two-dimensional SDS-PAGE and mass spectrometry. A total of 316 proteins were identified. Molecular changes during the development of the germinative tube were identified by a hierarchical clustering analysis based on the differential accumulation of proteins. Proteins associated with fungal filamentation, such as septin and kinesin, were detected only 4 h after germination (hag). A transcription factor related to biosynthesis of the secondary metabolite fumagillin, which can form hybrids with polyketides, was induced 2 hag, and polyketide synthase was observed 4 hag. The accumulation of ATP synthase, binding immunoglobulin protein (BiP), and catalase was validated by western blotting. In this study, we showed variations in protein expression during the early germination stages of fungus M. perniciosa. Proteins associated with fungal filamentation, and consequently with virulence, were detected in basidiospores 4 hag., for example, septin and kinesin. We discuss these results and propose a model of the germination of fungus M. perniciosa. This research can help elucidate the mechanisms underlying basic processes of host invasion and to develop strategies for control of the disease.

The impact of germination on the characteristics of brown rice flour and starch.

PubMed

Xu, Jie; Zhang, Hui; Guo, Xiaona; Qian, Haifeng

2012-01-30

In recent years, germinated brown rice as a functional food has received great attention with its improved sensory and nutritional properties. Particularly of interest are the high levels of γ-amino butyric acid (GABA) which can be obtained during germination. However, more studies are needed to fully understand the effect of germination on the physicochemical properties of brown rice. Germination altered the chemical composition of brown rice, resulting in an increase in reducing sugar and ash content, and a reduction in amylose. Solubility, paste viscosity, transition temperatures (T(o) , T(p) and T(c) ) and percentage of retrogradation (%Retrogradation) were decreased, while swelling power and turbidity were significantly increased. Scanning electron micrographs indicated that starch granules from germinated brown rice became smaller and less homogeneous. Moreover, germination shortened the chain length of amylopectin and amylose molecules. This investigation provides information on changes in the characteristics of rice flour and rice starch during germination, leading to a better understanding on the chemistry of brown rice germination. Copyright © 2011 Society of Chemical Industry.

Methyl jasmonate as an allelopathic agent: sagebrush inhibits germination of a neighboring tobacco, Nicotiana attenuata.

PubMed

Preston, Catherine A; Betts, Hazel; Baldwi, Ian T

2002-11-01

Artemisia tridentata ssp. tridentata is the dominant and defining shrub in the Great Basin Desert, with well-documented allelopathic tendencies that have generally been ascribed to its most abundantly released secondary metabolites. However, as a minor component, sagebrush releases a highly biologically active substance, methyljasmonate (MeJA), which is known to function as both a germination inhibitor and promoter in laboratory studies. Nicotiana attenuata is a tobacco species native to the Great Basin Desert and grows in newly burned juniper-sagebrush habitats for 2-3 yr following a fire. With a combination of field and laboratory studies, we examined the role of MeJA release from sagebrush by both air and water transport in inhibiting N. attenuata seed germination. We demonstrated that sagebrush interacts allelopathically with the seed bank of N. attenuata through its release of MeJA. In the field, seeds buried 0-40 cm from sagebrush plants for 4 months in net bags had significantly reduced germination compared to seeds buried similarly but protected in plastic bags. Moreover, germination on soils collected from underneath sagebrush plants was reduced by 60% compared to seeds placed on soils collected between sagebrush plants or outside of the sagebrush population. Exposure to A. tridentata seeds and seedlings did not affect N. attenuata germination, suggesting that established sagebrush plants only influence the tobacco's seed bank. In the laboratory, exposure of seeds to sagebrush emissions resulted in germination delays of up to 6 d. Exposure to volatile and aqueous MeJA also inhibited germination of N. attenuata seeds at quantities that are released naturally by sagebrush: 3.5 microg/hr and 1.12 microg/seed cup (56 ng/seed), respectively. A. tridentata seeds were significantly more resistant to MeJA, being inhibited at 336 microg MeJA (16.8 microg/seed), 300 times greater than the level of aqueous MeJA required to inhibit N. attenuata seeds. MeJA inhibited N

Improving the seed germination of little bluestem with selection

USDA-ARS?s Scientific Manuscript database

Rapid seed germination is an important characteristic when it comes to plant stand establishment under variable environmental conditions. This research was designed to improve the seed germination of six experimental Syn-0 lines of little bluestem [Schizachyrium scoparium (Michx.) Nash]. Two cycle...

An Arabidopsis thaliana embryo arrest mutant exhibiting germination potential

USDA-ARS?s Scientific Manuscript database

The ability to initiate radicle elongation, or germination potential, occurs in developing embryos before the completion of seed maturation. Green embryos after walking-stick stage in developing Arabidopsis thaliana seeds germinate when excised from seeds and incubated in MS media containing 1 % suc...

Greenhouse germination trials of pelletized western redcedar and red alder seeds

Treesearch

Nabil Khadduri

2007-01-01

Pelletized western redcedar (Thuja plicata Donn ex D. Don) and red alder (Alnus rubra Bong.) seeds exhibited lower total germination and delayed germination speed (G50 or days to 50% germination) when compared to non-pelletized “raw” seeds in greenhouse trials. Averaged across two lots of western redcedar, pelletizing decreased...

Effects of UV-B radiation on the isoflavone accumulation and physiological-biochemical changes of soybean during germination: Physiological-biochemical change of germinated soybean induced by UV-B.

PubMed

Ma, Meng; Wang, Pei; Yang, Runqiang; Gu, Zhenxin

2018-06-01

In this study, the effects of UV-B radiation on the isoflavones accumulation, physiological and nutritional quality, water status, and characteristics of proteins in germinated soybeans were investigated. The results showed that isoflavones content in soybeans increased with appropriate intensity and time of UV-B radiation and decreased with excessive treatment. Fresh weight, length, free amino acids, reducing sugar contents and bulk water (T 23 ) in germinated soybeans decreased with increasing radiation time, indicating that UV-B inhibited the growth and nutrients metabolism of soybean during germination. Cell damage was detected in germinated soybeans with excessive UV-B radiation, as shown by the black spots in cotyledons and the increased intercellular water determined by LF-NMR. Germination resulted in an increase in random coil structures, while UV-B radiation induced no obvious changes in FT-IR spectrum and protein conformation of soybeans. Both UV-B radiation and germination caused the increase in soluble proteins, especially in 1.0-75.0 kDa fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Seed dormancy and germination changes of snowbed species under climate warming: the role of pre- and post-dispersal temperatures.

PubMed

Bernareggi, Giulietta; Carbognani, Michele; Mondoni, Andrea; Petraglia, Alessandro

2016-09-01

Climate warming has major impacts on seed germination of several alpine species, hence on their regeneration capacity. Most studies have investigated the effects of warming after seed dispersal, and little is known about the effects a warmer parental environment may have on germination and dormancy of the seed progeny. Nevertheless, temperatures during seed development and maturation could alter the state of dormancy, affecting the timing of emergence and seedling survival. Here, the interplay between pre- and post-dispersal temperatures driving seed dormancy release and germination requirements of alpine plants were investigated. Three plant species inhabiting alpine snowbeds were exposed to an artificial warming treatment (i.e. +1·5 K) and to natural conditions in the field. Seeds produced were exposed to six different periods of cold stratification (0, 2, 4, 8, 12 and 20 weeks at 0 °C), followed by four incubation temperatures (5, 10, 15 and 20 °C) for germination testing. A warmer parental environment produced either no or a significant increase in germination, depending on the duration of cold stratification, incubation temperatures and their interaction. In contrast, the speed of germination was less sensitive to changes in the parental environment. Moreover, the effects of warming appeared to be linked to the level of (physiological) seed dormancy, with deeper dormant species showing major changes in response to incubation temperatures and less dormant species in response to cold stratification periods. Plants developed under warmer climates will produce seeds with changed germination responses to temperature and/or cold stratification, but the extent of these changes across species could be driven by seed dormancy traits. Transgenerational plastic adjustments of seed germination and dormancy shown here may result from increased seed viability, reduced primary and secondary dormancy state, or both, and may play a crucial role in future plant adaptation

Seed dormancy and germination changes of snowbed species under climate warming: the role of pre- and post-dispersal temperatures

PubMed Central

Bernareggi, Giulietta; Carbognani, Michele; Mondoni, Andrea; Petraglia, Alessandro

2016-01-01

Background and Aims Climate warming has major impacts on seed germination of several alpine species, hence on their regeneration capacity. Most studies have investigated the effects of warming after seed dispersal, and little is known about the effects a warmer parental environment may have on germination and dormancy of the seed progeny. Nevertheless, temperatures during seed development and maturation could alter the state of dormancy, affecting the timing of emergence and seedling survival. Here, the interplay between pre- and post-dispersal temperatures driving seed dormancy release and germination requirements of alpine plants were investigated. Methods Three plant species inhabiting alpine snowbeds were exposed to an artificial warming treatment (i.e. +1·5 K) and to natural conditions in the field. Seeds produced were exposed to six different periods of cold stratification (0, 2, 4, 8, 12 and 20 weeks at 0 °C), followed by four incubation temperatures (5, 10, 15 and 20 °C) for germination testing. Key Results A warmer parental environment produced either no or a significant increase in germination, depending on the duration of cold stratification, incubation temperatures and their interaction. In contrast, the speed of germination was less sensitive to changes in the parental environment. Moreover, the effects of warming appeared to be linked to the level of (physiological) seed dormancy, with deeper dormant species showing major changes in response to incubation temperatures and less dormant species in response to cold stratification periods. Conclusions Plants developed under warmer climates will produce seeds with changed germination responses to temperature and/or cold stratification, but the extent of these changes across species could be driven by seed dormancy traits. Transgenerational plastic adjustments of seed germination and dormancy shown here may result from increased seed viability, reduced primary and secondary dormancy state, or both, and

The Effect of Seasonal Ambient Temperatures on Fire-Stimulated Germination of Species with Physiological Dormancy: A Case Study Using Boronia (Rutaceae)

PubMed Central

Auld, Tony D.; Keith, David A.; Hui, Francis K. C.; Ooi, Mark K. J.

2016-01-01

Dormancy and germination requirements determine the timing and magnitude of seedling emergence, with important consequences for seedling survival and growth. Physiological dormancy is the most widespread form of dormancy in flowering plants, yet the seed ecology of species with this dormancy type is poorly understood in fire-prone vegetation. The role of seasonal temperatures as germination cues in these habitats is often overlooked due to a focus on direct fire cues such as heat shock and smoke, and little is known about the combined effects of multiple fire-related cues and environmental cues as these are seldom assessed in combination. We aimed to improve understanding of the germination requirements of species with physiological dormancy in fire-prone floras by investigating germination responses across members of the Rutaceae from south eastern Australia. We used a fully factorial experimental design to quantify the individual and combined effects of heat shock, smoke and seasonal ambient temperatures on germination of freshly dispersed seeds of seven species of Boronia, a large and difficult-to-germinate genus. Germination syndromes were highly variable but correlated with broad patterns in seed morphology and phylogenetic relationships between species. Seasonal temperatures influenced the rate and/or magnitude of germination responses in six species, and interacted with fire cues in complex ways. The combined effects of heat shock and smoke ranged from neutral to additive, synergistic, unitive or negative and varied with species, seasonal temperatures and duration of incubation. These responses could not be reliably predicted from the effect of the application of single cues. Based on these findings, fire season and fire intensity are predicted to affect both the magnitude and timing of seedling emergence in wild populations of species with physiological dormancy, with important implications for current fire management practices and for population

The Effect of Seasonal Ambient Temperatures on Fire-Stimulated Germination of Species with Physiological Dormancy: A Case Study Using Boronia (Rutaceae).

PubMed

Mackenzie, Berin D E; Auld, Tony D; Keith, David A; Hui, Francis K C; Ooi, Mark K J

2016-01-01

Dormancy and germination requirements determine the timing and magnitude of seedling emergence, with important consequences for seedling survival and growth. Physiological dormancy is the most widespread form of dormancy in flowering plants, yet the seed ecology of species with this dormancy type is poorly understood in fire-prone vegetation. The role of seasonal temperatures as germination cues in these habitats is often overlooked due to a focus on direct fire cues such as heat shock and smoke, and little is known about the combined effects of multiple fire-related cues and environmental cues as these are seldom assessed in combination. We aimed to improve understanding of the germination requirements of species with physiological dormancy in fire-prone floras by investigating germination responses across members of the Rutaceae from south eastern Australia. We used a fully factorial experimental design to quantify the individual and combined effects of heat shock, smoke and seasonal ambient temperatures on germination of freshly dispersed seeds of seven species of Boronia, a large and difficult-to-germinate genus. Germination syndromes were highly variable but correlated with broad patterns in seed morphology and phylogenetic relationships between species. Seasonal temperatures influenced the rate and/or magnitude of germination responses in six species, and interacted with fire cues in complex ways. The combined effects of heat shock and smoke ranged from neutral to additive, synergistic, unitive or negative and varied with species, seasonal temperatures and duration of incubation. These responses could not be reliably predicted from the effect of the application of single cues. Based on these findings, fire season and fire intensity are predicted to affect both the magnitude and timing of seedling emergence in wild populations of species with physiological dormancy, with important implications for current fire management practices and for population

Dipicolinic Acid Release by Germinating Clostridium difficile Spores Occurs through a Mechanosensing Mechanism.

PubMed

Francis, Michael B; Sorg, Joseph A

2016-01-01

Classically, dormant endospores are defined by their resistance properties, particularly their resistance to heat. Much of the heat resistance is due to the large amount of dipicolinic acid (DPA) stored within the spore core. During spore germination, DPA is released and allows for rehydration of the otherwise-dehydrated core. In Bacillus subtilis , 7 proteins are encoded by the spoVA operon and are important for DPA release. These proteins receive a signal from the activated germinant receptor and release DPA. This DPA activates the cortex lytic enzyme CwlJ, and cortex degradation begins. In Clostridium difficile , spore germination is initiated in response to certain bile acids and amino acids. These bile acids interact with the CspC germinant receptor, which then transfers the signal to the CspB protease. Activated CspB cleaves the cortex lytic enzyme, pro-SleC, to its active form. Subsequently, DPA is released from the core. C. difficile encodes orthologues of spoVAC , spoVAD , and spoVAE . Of these, the B. subtilis SpoVAC protein was shown to be capable of mechanosensing. Because cortex degradation precedes DPA release during C. difficile spore germination (opposite of what occurs in B. subtilis ), we hypothesized that cortex degradation would relieve the osmotic constraints placed on the inner spore membrane and permit DPA release. Here, we assayed germination in the presence of osmolytes, and we found that they can delay DPA release from germinating C. difficile spores while still permitting cortex degradation. Together, our results suggest that DPA release during C. difficile spore germination occurs though a mechanosensing mechanism. IMPORTANCE Clostridium difficile is transmitted between hosts in the form of a dormant spore, and germination by C. difficile spores is required to initiate infection, because the toxins that are necessary for disease are not deposited on the spore form. Importantly, the C. difficile spore germination pathway

Chemical investigation of Cyperus distans L. and inhibitory activity of scabequinone in seed germination and seedling growth bioassays.

PubMed

Vilhena, Karyme S S; Guilhon, Giselle Maria Skelding Pinheiro; Zoghbi, Maria das Graças B; Santos, Lourivaldo Silva; Souza Filho, Antonio Pedro Silva

2014-01-01

Chemical investigation of the rhizomes of Cyperus distans (Cyperaceae) led to the identification of α-ciperone, cyperotundone and scabequinone, besides other common constituents. Complete assignment of the (13)C NMR data of scabequinone is being published for the first time. The inhibitory effects of C. distans extracts and scabequinone on the seed germination and seedling growth of Mimosa pudica, Senna obtusifolia and Pueraria phaseoloides were evaluated. Seed germination inhibition bioassay revealed that S. obtusifolia (52-53%) was more sensitive to the hexane and the methanol extracts at 1% than M. pudica (0-10%). Scabequinone at 250 mg L⁻¹ displayed seed germination inhibitions more than 50% and radicle growth reduction of more than 35% of the test species S. obtusifolia and P. phaseoloides, while the hypocotyl growth of M. pudica was significantly affected (>50%) by the quinone at the same concentration. These results demonstrate that scabequinone contributes to the overall inhibitory activities of C. distans.

Compositional changes in (iso)flavonoids and estrogenic activity of three edible Lupinus species by germination and Rhizopus-elicitation.

PubMed

Aisyah, Siti; Vincken, Jean-Paul; Andini, Silvia; Mardiah, Zahara; Gruppen, Harry

2016-02-01

The effects of germination and elicitation on (iso)flavonoid composition of extracts from three edible lupine species (Lupinus luteus, Lupinus albus, Lupinus angustifolius) were determined by RP-UHPLC-MS(n). The total (iso)flavonoid content of lupine increased over 10-fold upon germination, with the total content and composition of isoflavonoids more affected than those of flavonoids. Glycosylated isoflavones were the most predominant compounds found in lupine seedlings. Lesser amounts of isoflavone aglycones, including prenylated ones, were also accumulated. Elicitation with Rhizopus oryzae, in addition to germination, raised the content of isoflavonoids further: the total content of 2'-hydroxygenistein derivatives was increased considerably, without increasing that of genistein derivatives. Elicitation by fungus triggered prenylation of isoflavonoids, especially of the 2'-hydroxygenistein derivatives. The preferred positions of prenylation differed among the three lupine species. The change in isoflavone composition increased the agonistic activity of the extracts towards the human estrogen receptors, whereas no antagonistic activity was observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of a long-term fire retardant (Fire Trol 934) on the germination of nine Mediterranean-type shrub species.

PubMed

Cruz, Alberto; Serrano, Marián; Navarro, Esther; Luna, Belén; Moreno, José M

2005-12-01

Fire Trol 934 is a long-term fire retardant commonly used in fire prevention and extinction. Our objective was to determine the effect of this chemical on seed germination of nine plant species from Mediterranean-type shrublands, where these chemicals are potentially used. Seeds were exposed to five different Fire Trol concentrations, (0 (control) to 10%, on a log scale) and monitored in a germination chamber for nine weeks. Seeds from four Cistus species were subjected to an additional heat treatment that simulated thermal scarification caused by fire. Retardant exposure caused a significant decrease in total germination in all species, and exposure to the highest Fire Trol concentration (10%) resulted in complete inhibition of germination. However, the sensitivity to Fire Trol varied across species and this differential species sensitivity may potentially lead to different impacts in the soil seed banks depending on whether sites are burned or unburned. Exposure to Fire Trol 934 may affect recruitment of shrubland species particularly during dry autumns, due to limited leaching of these chemicals from the soil surface. Consequently, its use should be avoided in sites where particularly sensitive plant species are present. Copyright (c) 2005 Wiley Periodicals, Inc.

Anaerobic conditions improve germination of a gibberellic acid deficient rice

NASA Technical Reports Server (NTRS)

Frantz, Jonathan M.; Bugbee, Bruce

2002-01-01

Dwarf plants are useful in research because multiple plants can be grown in a small area. Rice (Oryza sativa L.) is especially important since its relatively simple genome has recently been sequenced. We are characterizing a gibberellic acid (GA) mutant of rice (japonica cv 'Shiokari,' line N-71) that is extremely dwarf (20 cm tall). Unfortunately, this GA mutation is associated with poor germination (70%) under aerobic conditions. Neither exogenous GA nor a dormancy-breaking heat treatment improved germination. However, 95% germination was achieved by germinating the seeds anaerobically, either in a pure N2 environment or submerged in unstirred tap water. The anaerobic conditions appear to break a mild post-harvest dormancy in this rice cultivar. Copyright 2002 Crop Science Society of America.

Anaerobic conditions improve germination of a gibberellic acid deficient rice.

PubMed

Frantz, Jonathan M; Bugbee, Bruce

2002-01-01

Dwarf plants are useful in research because multiple plants can be grown in a small area. Rice (Oryza sativa L.) is especially important since its relatively simple genome has recently been sequenced. We are characterizing a gibberellic acid (GA) mutant of rice (japonica cv 'Shiokari,' line N-71) that is extremely dwarf (20 cm tall). Unfortunately, this GA mutation is associated with poor germination (70%) under aerobic conditions. Neither exogenous GA nor a dormancy-breaking heat treatment improved germination. However, 95% germination was achieved by germinating the seeds anaerobically, either in a pure N2 environment or submerged in unstirred tap water. The anaerobic conditions appear to break a mild post-harvest dormancy in this rice cultivar. Copyright 2002 Crop Science Society of America.

Food Quality Improvement of Soy Milk Made from Short-Time Germinated Soybeans

PubMed Central

Jiang, Susu; Cai, Weixi; Xu, Baojun

2013-01-01

The objectives of this study were to develop soy milk with improved food quality and to enhance the functional attributes by incorporating short-time germination into the processing. Changes in trypsin inhibitor activity (TIA), phytic acid content and total phenolic content (TPC) in soy milk produced from soybeans germinated within 72 h were investigated to determine the optimum germination condition. Results from the present research showed significant (p < 0.05) improvement of TPC in cooked germinated soybean milk, while both the TIA and phytic acid content were decreased significantly (p < 0.05). In the subsequent evaluation on the quality attributes under the optimum germination condition, soy milk made from 28 h-germinated soybeans presented enhanced nutritional value and comparable physicochemical properties to conventional soy milk. The current approach provides a feasible and convenient way for soy-based product innovation in both household and industrial settings. PMID:28239109

The evolution of pollen germination timing in flowering plants: Austrobaileya scandens (Austrobaileyaceae)

PubMed Central

Williams, Joseph H.

2012-01-01

Background and aims The pollination to fertilization process (progamic phase) is thought to have become greatly abbreviated with the origin of flowering plants. In order to understand what developmental mechanisms enabled the speeding of fertilization, comparative data are needed from across the group, especially from early-divergent lineages. I studied the pollen germination process of Austrobaileya scandens, a perennial vine endemic to the Wet Tropics area of northeastern Queensland, Australia, and a member of the ancient angiosperm lineage, Austrobaileyales. Methodology I used in vivo and in vitro hand pollinations and timed collections to study development from late pollen maturation to just after germination. Then I compared the contribution of pollen germination timing to progamic phase duration in 131 angiosperm species (65 families). Principal findings Mature pollen of Austrobaileya was bicellular, starchless and moderately dehydrated—water content was 31.5 % by weight and volume increased by 57.9 % upon hydration. A callose layer in the inner intine appeared only after pollination. In vivo pollen germination followed a logarithmic curve, rising from 28 % at 1 hour after pollination (hap) to 97 % at 12 hap (R2 = 0.98). Sufficient pollen germination to fertilize all ovules was predicted to have occurred within 62 min. Across angiosperms, pollen germination ranged from 1 min to >60 h long and required 8.3 ± 9.8 % of the total duration of the progamic phase. Significance Pollen of Austrobaileya has many plesiomorphic features that are thought to prolong germination. Yet its germination is quite fast for species with desiccation-tolerant pollen (range: <1 to 60 h). Austrobaileya and other early-divergent angiosperms have relatively rapid pollen germination and short progamic phases, comparable to those of many insect-pollinated monocots and eudicots. These results suggest that both the pollen germination and pollen tube growth periods were marked by

The evolution of pollen germination timing in flowering plants: Austrobaileya scandens (Austrobaileyaceae).

PubMed

Williams, Joseph H

2012-01-01

The pollination to fertilization process (progamic phase) is thought to have become greatly abbreviated with the origin of flowering plants. In order to understand what developmental mechanisms enabled the speeding of fertilization, comparative data are needed from across the group, especially from early-divergent lineages. I studied the pollen germination process of Austrobaileya scandens, a perennial vine endemic to the Wet Tropics area of northeastern Queensland, Australia, and a member of the ancient angiosperm lineage, Austrobaileyales. I used in vivo and in vitro hand pollinations and timed collections to study development from late pollen maturation to just after germination. Then I compared the contribution of pollen germination timing to progamic phase duration in 131 angiosperm species (65 families). Mature pollen of Austrobaileya was bicellular, starchless and moderately dehydrated-water content was 31.5 % by weight and volume increased by 57.9 % upon hydration. A callose layer in the inner intine appeared only after pollination. In vivo pollen germination followed a logarithmic curve, rising from 28 % at 1 hour after pollination (hap) to 97 % at 12 hap (R(2) = 0.98). Sufficient pollen germination to fertilize all ovules was predicted to have occurred within 62 min. Across angiosperms, pollen germination ranged from 1 min to >60 h long and required 8.3 ± 9.8 % of the total duration of the progamic phase. Pollen of Austrobaileya has many plesiomorphic features that are thought to prolong germination. Yet its germination is quite fast for species with desiccation-tolerant pollen (range: <1 to 60 h). Austrobaileya and other early-divergent angiosperms have relatively rapid pollen germination and short progamic phases, comparable to those of many insect-pollinated monocots and eudicots. These results suggest that both the pollen germination and pollen tube growth periods were marked by acceleration of developmental processes early in angiosperm history.

[Seed vigor evaluation based on adversity resistance index of wheat seed germination under stress conditions.

PubMed

Chen, Lei Tai; Sun, Ai Qing; Yang, Min; Chen, Lu Lu; Ma, Xue Li; Li, Mei Ling; Yin, Yan Ping

2016-09-01

A total of 16 wheat cultivars were selected to detect seed vigor of different genotypes using standard germination test, seed germination test under stress conditions and field emergence test. The adversity resistance indices of seed vigor indices and field emergence percentage under different germination conditions were used as the indices to evaluate adversity resistance. Principal component analysis and cluster analysis were used for the comprehensive evaluation of seed vigor. Results showed that drought stress, artificial aging and cold soaking treatments affected seed vigor to some extent. The adversity resistance indices of the artificial aging and cold soaking tests were significantly positively correlated with the field emergence percentage, while the adversity resistance index of drought stress test had no significant correlation with the field emergence percentage. 16 wheat cultivars were classified as three groups based on the principal component analysis and cluster analysis. Yunong 949, Yumai 49-198, Luyuan 502, Zhengyumai 9987, Shimai 21, Shannong 23, and Shixin 828 belonged to high vigor seeds. Xunong 5, Yunong 982, Tangmai 8, Jimai 20, Jimai 22, Jinan 17, and Shannong 20 belonged to medium vigor seeds. The other two cultivars, Chang 4738 and Lunxuan 061, belonged to low vigor seeds.

Gibberellin Signaling: a Wake-up Call for Seed Germination

USDA-ARS?s Scientific Manuscript database

Making an appropriate decision to germinate is essential for the survival of plant species and is important for proper stand establishment in crop plants. Germination is regulated by the antagonistic effects to two plant hormones in Arabidopsis thaliana: abscisic acid (ABA) induces dormancy and repr...

Nutritional Factors Affecting Adult Neurogenesis and Cognitive Function.

PubMed

Poulose, Shibu M; Miller, Marshall G; Scott, Tammy; Shukitt-Hale, Barbara

2017-11-01

Adult neurogenesis, a complex process by which stem cells in the hippocampal brain region differentiate and proliferate into new neurons and other resident brain cells, is known to be affected by many intrinsic and extrinsic factors, including diet. Neurogenesis plays a critical role in neural plasticity, brain homeostasis, and maintenance in the central nervous system and is a crucial factor in preserving the cognitive function and repair of damaged brain cells affected by aging and brain disorders. Intrinsic factors such as aging, neuroinflammation, oxidative stress, and brain injury, as well as lifestyle factors such as high-fat and high-sugar diets and alcohol and opioid addiction, negatively affect adult neurogenesis. Conversely, many dietary components such as curcumin, resveratrol, blueberry polyphenols, sulforaphane, salvionic acid, polyunsaturated fatty acids (PUFAs), and diets enriched with polyphenols and PUFAs, as well as caloric restriction, physical exercise, and learning, have been shown to induce neurogenesis in adult brains. Although many of the underlying mechanisms by which nutrients and dietary factors affect adult neurogenesis have yet to be determined, nutritional approaches provide promising prospects to stimulate adult neurogenesis and combat neurodegenerative diseases and cognitive decline. In this review, we summarize the evidence supporting the role of nutritional factors in modifying adult neurogenesis and their potential to preserve cognitive function during aging. © 2017 American Society for Nutrition.

Seed dormancy and germination of Ficus lundellii and tropical forest restoration.

PubMed

Garcia, Ximena; Hong, Tran D; Ellis, Richard H

2006-01-01

We investigated seed dormancy and germination in Ficus lundellii Standl. (Moraceae), a native species of Mexico's Los Tuxtlas tropical rain forest. In an 8-h photoperiod at an alternating diurnal (16/8 h) temperature of 20/30 degrees C, germination was essentially complete (96%) within 28 days, whereas in darkness, all seeds remained dormant. Neither potassium nitrate (0.05-0.2%) applied continuously nor gibberellic acid applied either continuously (10-200 ppm) or as a 24 hour pretreatment (2000 ppm) induced germination in the dark. Germination in the light was not reduced by a 24-h hydrochloric acid (0.1-1%) pretreatment, but it was reduced both by a 24-h pretreatment with either H(2)O(2) (0.1-5 M) or 5% HCl, or by more than 5 days of storage at 40 degrees C (4.5% seed water content). In a study with a 2-dimensional temperature gradient plate, seeds germinated fully and rapidly in the light at a constant temperature of 30 degrees C, and fully but less rapidly in the light at alternating temperatures with low amplitudes (< 12 degrees C) about the optimal constant temperature. The base, optimal and ceiling temperatures for rate of germination were estimated as 13.8, 30.1 and 41.1 degrees C, respectively. In all temperature regimes, light was essential for the germination of F. lundellii seeds.

Germination and growth of wheat in simulated Martian atmospheres