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1

Molecular characterization of Chilli leaf curl virus and satellite molecules associated with leaf curl disease of Amaranthus spp.  

PubMed

Amaranthus, collectively known as amaranth, is an annual or short-lived perennial plant used as leafy vegetables, cereals and for ornamental purposes in many countries including India. During 2011, leaf samples of Amaranthus plants displaying leaf curling, leaf distortion, leaf crinkling and yellow leaf margins were collected from Banswara district, Rajasthan in India. Full-length clones of a monopartite begomovirus, a betasatellite and an alphasatellite were characterized. The complete nucleotide sequence of the isolated begomovirus features as a typical 'Old World' begomovirus with the highest nucleotide per cent identity with Chilli leaf curl virus and hence, considered as an isolate of Chilli leaf curl virus. The complete nucleotide sequences of betasatellite and alphasatellite possess maximum nucleotide identity with Tomato yellow leaf curl Thailand betasatellite and Chilli leaf curl alphasatellite, respectively. This is the first report of the association of chilli-infecting begomovirus and satellite molecules infecting a new host, Amaranthus, causing leaf curl disease. PMID:24368759

George, B; Kumar, R Vinoth; Chakraborty, S

2014-04-01

2

A worldwide survey of tomato yellow leaf curl viruses  

Microsoft Academic Search

Summary.  ?The name tomato yellow leaf curl virus (TYLCV) has been given to several whitefly-transmitted geminiviruses affecting tomato\\u000a cultures in many tropical and subtropical regions. Hybridization tests with two DNA probes derived from a cloned isolate of\\u000a TYLCV from Israel (TYLCV-ISR) were used to assess the affinities of viruses in naturally infected tomato plants with yellow\\u000a leaf curl or leaf curl

H. Czosnek; H. Laterrot

1997-01-01

3

Genetic variability of Cotton leaf curl betasatellite in Northern India.  

PubMed

Cotton is an important crop and its production is affected by various disease pathogens. Monopartite begomovirus associated betasatellites cause Cotton leaf curl disease (CLCuD) in Northern India. In order to access the occurrence and genetic variability of Cotton leaf curl betasatellites, an extensive field survey was conducted in states of Rajasthan, Punjab and Haryana. We selected the betasatellite sequence for analysis as they are reported as important for disease severity and sequence variability. Based on the field observations, the disease incidence ranged from 30% to 80% during the survey. Full genome and DNA ? were amplified from various samples while no amplicon was obtained in some samples. The nucleotide sequence homology ranged from 90.0% to 98.7% with Cotton leaf curl virus (CLCuV), 55.2-55.5% with Bhendi yellow vein mosaic virus, 55.8% with Okra leaf curl virus and 51.70% with Tomato leaf curl virus isolates. The lowest similarity (47.8%) was found in CLCuV-Sudan isolate. Phylogenetic analysis showed that analyzed isolates formed a close cluster with various CLCuV isolates reported earlier. The analysis results show sequence variation in Cotton leaf curl betasatellite which could be the result of recombination. The results obtained by genome amplification and sequence variability indicate that some new variants are circulating and causing leaf curl disease in Rajasthan, Punjab and Haryana. PMID:25473373

Sohrab, Sayed Sartaj; Azhar, Esam I; Kamal, Mohammad A; Bhattacharya, P S; Rana, D

2014-12-01

4

Genetic variability of Cotton leaf curl betasatellite in Northern India  

PubMed Central

Cotton is an important crop and its production is affected by various disease pathogens. Monopartite begomovirus associated betasatellites cause Cotton leaf curl disease (CLCuD) in Northern India. In order to access the occurrence and genetic variability of Cotton leaf curl betasatellites, an extensive field survey was conducted in states of Rajasthan, Punjab and Haryana. We selected the betasatellite sequence for analysis as they are reported as important for disease severity and sequence variability. Based on the field observations, the disease incidence ranged from 30% to 80% during the survey. Full genome and DNA ? were amplified from various samples while no amplicon was obtained in some samples. The nucleotide sequence homology ranged from 90.0% to 98.7% with Cotton leaf curl virus (CLCuV), 55.2–55.5% with Bhendi yellow vein mosaic virus, 55.8% with Okra leaf curl virus and 51.70% with Tomato leaf curl virus isolates. The lowest similarity (47.8%) was found in CLCuV-Sudan isolate. Phylogenetic analysis showed that analyzed isolates formed a close cluster with various CLCuV isolates reported earlier. The analysis results show sequence variation in Cotton leaf curl betasatellite which could be the result of recombination. The results obtained by genome amplification and sequence variability indicate that some new variants are circulating and causing leaf curl disease in Rajasthan, Punjab and Haryana. PMID:25473373

Sohrab, Sayed Sartaj; Azhar, Esam I.; Kamal, Mohammad A.; Bhattacharya, P.S.; Rana, D.

2014-01-01

5

Differential disease phenotype of begomoviruses associated with tobacco leaf curl disease in Comoros.  

PubMed

In the 2000s, tobacco plantations on the Comoros Islands were afflicted with a previously unobserved tobacco leaf curl disease characterised by symptoms of severe leaf curling and deformation. Previous molecular characterization of potential viral pathogens revealed a complex of African monopartite tobacco leaf curl begomovirus (TbLCVs). Our molecular investigation allowed the characterization of a new monopartite virus involved in the disease: tomato leaf curl Namakely virus (ToLCNamV). Agroinoculation experiments indicated that TbLCVs and tomato leaf curl viruses (ToLCVs) can infect both tomato and tobacco but that infectivity and symptom expression fluctuate depending on the virus and the plant cultivar combination. PMID:22187103

Thierry, M; Lefeuvre, P; Hoareau, M; Péréfarres, F; Delatte, H; Reynaud, B; Martin, D P; Lett, J-M

2012-03-01

6

?C1 of chili leaf curl betasatellite is a pathogenicity determinant  

PubMed Central

Background Cotton leaf curl disease in the Indian subcontinent is associated with several distinct begomoviruses that interact with a disease-specific DNA satellite named Cotton leaf curl Multan betasatellite (CLCuMB). However, we have recently reported that Chili leaf curl betasatellite (ChLCB) is also occasionally found associated with the disease in Pakistan. The question as to whether ChLCB contributes to the development of disease symptoms such as leaf curling and enations remain to be answered. We have previously shown that the expression of ?C1 of CLCuMB develops all symptoms of cotton leaf curl disease in Nicotiana benthamiana when expressed from PVX vector. Findings The role of ChLCB in the induction of typical disease symptoms was studied by its expression from PVX vector in N. benthamiana. The expression of ?C1 from PVX vector developed severe leaf curl symptoms and leaf-like enations that resemble the phenotype induced by ?C1 of CLCuMB. Conclusions The results presented here show that the expression of ?C1 of ChLCB from PVX vector exhibit phenotype typical of cotton leaf curl and therefore ChLCB may contribute to the disease symptoms. PMID:22067326

2011-01-01

7

Transcript mapping of Cotton leaf curl Burewala virus and its cognate betasatellite, Cotton leaf curl Multan betasatellite  

PubMed Central

Background Whitefly-transmitted geminiviruses (family Geminiviridae, genus Begomovirus) are major limiting factors for the production of numerous dicotyledonous crops throughout the warmer regions of the world. In the Old World a small number of begomoviruses have genomes consisting of two components whereas the majority have single-component genomes. Most of the monopartite begomoviruses associate with satellite DNA molecules, the most important of which are the betasatellites. Cotton leaf curl disease (CLCuD) is one of the major problems for cotton production on the Indian sub-continent. Across Pakistan, CLCuD is currently associated with a single begomovirus (Cotton leaf curl Burewala virus [CLCuBuV]) and the cotton-specific betasatellite Cotton leaf curl Multan betasatellite (CLCuMuB), both of which have recombinant origins. Surprisingly, CLCuBuV lacks C2, one of the genes present in all previously characterized begomoviruses. Virus-specific transcripts have only been mapped for few begomoviruses, including one monopartite begomovirus that does not associate with betasatellites. Similarly, the transcripts of only two betasatellites have been mapped so far. The study described has investigated whether the recombination/mutation events involved in the evolution of CLCuBuV and its associated CLCuMuB have affected their transcription strategies. Results The major transcripts of CLCuBuV and its associated betasatellite (CLCuMuB) from infected Nicotiana benthamiana plants have been determined. Two complementary-sense transcripts of ~1.7 and ~0.7 kb were identified for CLCuBuV. The ~1.7 kb transcript appears similar in position and size to that of several begomoviruses and likely directs the translation of C1 and C4 proteins. Both complementary-sense transcripts can potentially direct the translation of C2 and C3 proteins. A single virion-sense transcript of ~1 kb, suitable for translation of the V1 and V2 genes was identified. A predominant complementary-sense transcript was also confirmed for the betasatellite. Conclusions Overall, the transcription of CLCuBuV and the recombinant CLCuMuB is equivalent to earlier mapped begomoviruses/betasatellites. The recombination events that featured in the origins of these components had no detectable effects on transcription. The transcripts spanning the mutated C2 gene showed no evidence for involvement of splicing in restoring the ability to express intact C2 protein. PMID:23106938

2012-01-01

8

Posttranscriptional gene silencing in controlling viruses of the Tomato yellow leaf curl virus complex  

Microsoft Academic Search

Summary.  Tomato yellow leaf curl disease (TYLCD) is caused by a group of geminiviruses that belong to the Tomato yellow leaf curl virus\\u000a (TYLCV) complex and are transmitted by the whitefly (Bemisia tabaci Genn.). The disease causes great yield losses in many countries throughout the Mediterranean region and the Middle East.\\u000a In this study, the efficacy of post-transcriptional gene silencing (PTGS)

M. K. Abhary; G. H. Anfoka; M. K. Nakhla; D. P. Maxwell

2006-01-01

9

Infectious clones of Tomato leaf curl Palampur virus with a defective DNA B and their pseudo-recombination with Tomato leaf curl New Delhi virus  

PubMed Central

Background Tomato leaf curl Palampur virus (ToLCPMV) is a bipartite begomovirus which has been reported from India and Iran but infectious clones have not been obtained. We have previously shown the association of Zucchini yellow mosaic virus (ZYMV), a potyvirus, with severe leaf curl disease of muskmelon in Pakistan. However, the severity of symptoms in the field and yield losses led us to believe that some other agent, such as a begomovirus, could be associated with the disease. Results A bipartite begomovirus associated with a severe yellow leaf curl disease on muskmelon in Pakistan has been characterized. Analysis of the complete nucleotide sequence of the DNA A and DNA B components of the begomovirus showed that it has the highest DNA sequence identity with ToLCPMV. However, the gene encoding the nuclear shuttle protein (NSP) was truncated in comparison to previously characterised isolates. Agrobacterium-mediated inoculation of Nicotiana benthamiana with the ToLCPMV clones obtained here did not result in symptoms. However, inoculation of plants with the DNA A component of ToLCPMV and the DNA B component of Tomato leaf curl New Delhi virus (ToLCNDV) lead to systemic infection with leaf curl symptoms. This suggested that the lack of infectivity of the ToLCPMV clones was due to the defect in DNA B. The DNA B of ToLCPMV was able to move systemically when inoculated with DNA A of the either virus. Agro-infiltration of muskmelon with the DNA A and DNA B components of ToLCPMV did not lead to symptomatic infection whereas inoculation with the DNA A with the DNA B of ToLCNDV resulted in a hypersensitive response (HR) along the veins. Additionally, agro-infiltration of muskmelon with a construct for the expression of the NSP gene of ToLCNDV under the control of the cauliflower mosaic virus 35S promoter induced a HR, suggesting that this is the gene causing the HR. Conclusions Both ToLCPMV and ZYMV are associated with muskmelon leaf curl disease in Pakistan. However, the ToLCPMV variant identified in association with ZYMV has a defective NSP. The results suggest that a variant with a defective NSP may have been selected for in muskmelon, as this protein is an avirulence determinant in this species, and possibly that infection requires the synergistic interaction with ZYMV. PMID:21496256

2011-01-01

10

Genetic diversity of Sweet potato begomoviruses in the United States and identification of a natural recombinant between Sweet potato leaf curl virus and Sweet potato leaf curl Georgia virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the United States, two sweetpotato begomoviruses, Sweet potato leaf curl virus (SPLCV) and Sweet potato leaf curl Georgia virus (SPLCGV) were previously identified in Louisiana. In recent years, at least seven additional sweetpotato begomoviruses have been identified in other parts of the world....

11

Replication of tomato yellow leaf curl virus (TYLCV) DNA in agroinoculated leaf discs from selected tomato genotypes  

Microsoft Academic Search

The leaf disc agroinoculation system was applied to study tomato yellow leaf curl virus (TYLCV) replication in explants from susceptible and resistant tomato genotypes. This system was also evaluated as a potential selection tool in breeding programmes for TYLCV resistance. Leaf discs were incubated with a head-to-tail dimer of the TYLCV genome cloned into the Ti plasmid ofAgrobacterium tumefaciens. In

H. Czosnek; A. Kheyr-Pour; B. Gronenborn; E. Remetz; M. Zeidan; A. Altman; H. D. Rabinowitch; S. Vidavsky; N. Kedar; Y. Gafni; D. Zamir

1993-01-01

12

A multiplex PCR method discriminating between the TYLCV and TYLCV-Mld clades of Tomato yellow leaf curl virus  

Microsoft Academic Search

Tomato yellow leaf curl virus (TYLCV) is one of the causal agents of tomato yellow leaf curl disease (TYLCD) and can cause up to 100% yield losses in tomato fields. As TYLCV continues to spread, many isolates have been described in different parts of the world. Recently two closely related but distinct TYLCV clades, called TYLCV and TYLCV-Mld, have been

P. Lefeuvre; M. Hoareau; H. Delatte; B. Reynaud; J.-M. Lett

2007-01-01

13

Rate of Tomato yellow leaf curl virus Translocation in the Circulative Transmission Pathway of its Vector, the Whitefly Bemisia tabaci  

Microsoft Academic Search

Ghanim, M., Morin, S., and Czosnek, H. 2001. Rate of Tomato yellow leaf curl virus translocation in the circulative transmission pathway of its vector, the whitefly Bemisia tabaci. Phytopathology 91:188-196. Whiteflies (Bemisia tabaci, biotype B) were able to transmit Tomato yellow leaf curl virus (TYLCV) 8 h after they were caged with infected tomato plants. The spread of TYLCV during

Murad Ghanim; Shai Morin; Henryk Czosnek

2001-01-01

14

The circulative pathway of begomoviruses in the whitefly vector Bemisia tabaci - insights from studies with Tomato yellow leaf curl virus  

Microsoft Academic Search

Summary Our current knowledge concerning the transmission of begomoviruses by the whitefly vector Bemisia tabaci is based mainly on research performed on the Tomato yellow leaf curl virus (TYLCV) complex and on a number of viruses originating from the Old World, such as Tomato leaf curl virus , and from the New World, including Abutilon mosaic virus , Tomato mottle

HENRYK CZOSNEK; MIRIAM GHANIM; MURAD GHANIM

2002-01-01

15

Sweet Potato Leaf Curl Virus: Virus Reservoir in Species of Wild Morning Glory  

Technology Transfer Automated Retrieval System (TEKTRAN)

Recent increases in populations of the Sweetpotato leaf curl virus (SPLCV) vector, the sweetpotato whitefly, Bemisia tabaci (Gennadius), led to a dramatic increase in the disease in sweetpotato (Ipomoea batatas). Knowledge of crop or weed species that occur in sweetpotato growing areas and can serv...

16

Whitefly transmission of Sweet potato leaf curl virus in sweetpotato germplasm  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sweetpotato, Ipomoea batatas (L.) Lam., is among an extensive number of plant species attacked by Bemisia tabaci (Gennadius). Because this important world food crop is vegetatively propagated, it can conveniently accumulate infections by several viruses. Sweet potato leaf curl virus (SPLCV) (ssDNA...

17

Management of sweet potato leaf curl virus in sweetpotatoes using insecticides  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sweetpotato leaf curl virus (SPLCV), which is transmitted by the sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), can severely affect yields of commercial sweetpotatoes, Ipomoea batatas (L.) Lam. (Convolvulaceae). This virus occurs every year at the U.S. Vegetable Laborato...

18

Effect of Tomato yellow leaf curl bigeminivirus (TYLCV) infection on tomato cell ultrastructure and physiology  

Microsoft Academic Search

Tomato yellow leaf curl bigeminivirus was isolated in Kuwait and therefore designated as TYLCV-K. The virus was found to be transmitted by whiteflies (Bemisia tabaci Genn.), and produced the characteristic external symptoms on tomato (Solanum lycopersicum L.) test plants. Electron microscopy of ultra-thin sections of infected leaves showed alterations in the ultrastructure of some organelles and uneven thickenings of the

Magdy S. Montasser; Fadaa D. Al-Own; Asma M. Haneif; Mohammad Afzal

2012-01-01

19

Engineering resistance against tomato yellow leaf curl virus (TYLCV) using antisense RNA  

Microsoft Academic Search

One of the most severe diseases of cultivated tomato worldwide is caused by tomato yellow leaf curl virus (TYLCV), a geminivirus transmitted by the whitefly Bemisia tabaci. Here we describe the application of antisense RNAs to interfere with the disease caused by TYLCV. The target of the antisense RNA is the rare messenger RNA of the Rep protein, encoded by

Mohammed Bendahmane; Bruno Gronenborn

1997-01-01

20

Multiple Introductions of the Old World Begomovirus Tomato yellow leaf curl virus into the New World?  

PubMed Central

A phylogenetic analysis of three genomic regions revealed that Tomato yellow leaf curl virus (TYLCV) from western North America is distinct from TYLCV isolated in eastern North America and the Caribbean. This analysis supports a second introduction of this Old World begomovirus into the New World, most likely from Asia. PMID:17827315

Duffy, Siobain; Holmes, Edward C.

2007-01-01

21

Use of Insecticides to Control the Spread of Sweetpotato Leaf Curl Virus in Sweetpotato Fields  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sweetpotato leaf curl virus (SPLCV), which is transmitted by the sweetpotato whitefly, can severely affect yields of commercial sweetpotato cultivars. This virus occurs every year at the U.S. Vegetable Laboratory (USVL), Charleston, SC. In 2010 and 2011, small plots of virus tested ‘Beauregard’ sw...

22

A DNA? Associated with Tomato Yellow Leaf Curl China Virus Is Required for Symptom Induction  

PubMed Central

We report here that all 25 isolates of Tomato yellow leaf curl China virus (TYLCCNV) collected from tobacco, tomato, or Siegesbeckia orientalis plants in different regions of Yunnan Province, China, were associated with DNA? molecules. To investigate the biological role of DNA?, full-length infectious clones of viral DNA and DNA? of TYLCCNV isolate Y10 (TYLCCNV-Y10) were agroinoculated into Nicotiana benthamiana, Nicotiana glutinosa, Nicotiana. tabacum Samsun (NN or nn), tomato, and petunia plants. We found that TYLCCNV-Y10 alone could systemically infect these plants, but no symptoms were induced. TYLCCNV-Y10 DNA? was required, in addition to TYLCCNV-Y10, for induction of leaf curl disease in these hosts. Similar to TYLCCNV-Y10, DNA? of TYLCCNV isolate Y64 was also found to be required for induction of typical leaf curl diseases in the hosts tested. When the ?C1 gene of TYLCCNV-Y10 DNA? was mutated, the mutants failed to induce leaf curl symptoms in N. benthamiana when coinoculated with TYLCCNV-Y10. However, Southern blot hybridization analyses showed that the mutated DNA? molecules were replicated. When N. benthamiana and N. tabacum plants were transformed with a construct containing the ?C1 gene under the control of the Cauliflower mosaic virus 35S promoter, many transgenic plants developed leaf curl symptoms similar to those caused by a virus, the severity of which paralleled the level of ?C1 transcripts, while transgenic plants transformed with the ?C1 gene containing a stop codon after the start codon remained symptomless. Thus, expression of a ?C1 gene is adequate for induction of symptoms of viral infection in the absence of virus. PMID:15564504

Cui, Xiaofeng; Tao, Xiaorong; Xie, Yan; Fauquet, Claude M.; Zhou, Xueping

2004-01-01

23

Biology and interactions of two distinct monopartite begomoviruses and betasatellites associated with radish leaf curl disease in India  

PubMed Central

Background Emerging whitefly transmitted begomoviruses are major pathogens of vegetable and fibre crops throughout the world, particularly in tropical and sub-tropical regions. Mutation, pseudorecombination and recombination are driving forces for the emergence and evolution of new crop-infecting begomoviruses. Leaf curl disease of field grown radish plants was noticed in Varanasi and Pataudi region of northern India. We have identified and characterized two distinct monopartite begomoviruses and associated beta satellite DNA causing leaf curl disease of radish (Raphanus sativus) in India. Results We demonstrate that RaLCD is caused by a complex of two Old World begomoviruses and their associated betasatellites. Radish leaf curl virus-Varanasi is identified as a new recombinant species, Radish leaf curl virus (RaLCV) sharing maximum nucleotide identity of 87.7% with Tomato leaf curl Bangladesh virus-[Bangladesh:2] (Accession number AF188481) while the virus causing radish leaf curl disease-Pataudi is an isolate of Croton yellow vein mosaic virus-[India] (CYVMV-IN) (Accession number AJ507777) sharing 95.8% nucleotide identity. Further, RDP analysis revealed that the RaLCV has a hybrid genome, a putative recombinant between Euphorbia leaf curl virus and Papaya leaf curl virus. Cloned DNA of either RaLCV or CYVMV induced mild leaf curl symptoms in radish plants. However, when these clones (RaLCV or CYVMV) were individually co-inoculated with their associated cloned DNA betasatellite, symptom severity and viral DNA levels were increased in radish plants and induced typical RaLCD symptoms. To further extend these studies, we carried out an investigation of the interaction of these radish-infecting begomoviruses and their associated satellite, with two tomato infecting begomoviruses (Tomato leaf curl Gujarat virus and Tomato leaf curl New Delhi virus). Both of the tomato-infecting begomoviruses showed a contrasting and differential interaction with DNA satellites, not only in the capacity to interact with these molecules but also in the modulation of symptom phenotypes by the satellites. Conclusion This is the first report and experimental demonstration of Koch's postulate for begomoviruses associated with radish leaf curl disease. Further observations also provide direct evidence of lateral movement of weed infecting begomovirus in the cultivated crops and the present study also suggests that the exchange of betasatellites with other begomoviruses would create a new disease complex posing a serious threat to crop production. PMID:22339942

2012-01-01

24

Molecular characterization of Chilli leaf curl viruses infecting new host plant Petunia hybrida in India.  

PubMed

Petunia hybrida is an important ornamental plant grown in many countries including India. It is a good model plant for the study of genetics and molecular biology. During a survey in 2013-2014, severe leaf curling was observed on most of the P. hybrida grown in the Sikar district, Rajasthan. The infected plants were analyzed for begomovirus infection by rolling circular amplification (RCA) and sequenced. Full length sequences confirmed the association of monopartite begomovirus with betasatellites. Phylogenetic analysis showed the highest percentage of identity with Chilli leaf curl virus (ChLCuV) and therefore considered to be an isolate of ChLCuV. Recombination analysis showed that ChLCuV has broadened its host range by recombination process. To the best our knowledge, this is the first report of natural occurrence of ChLCuV on P. hybrida in India. PMID:25294775

Nehra, Chitra; Gaur, R K

2014-10-01

25

Resistance-driven selection of begomoviruses associated with the tomato yellow leaf curl disease.  

PubMed

Tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato crops worldwide. The deployment of host-plant resistance is the most desirable mean to control this disease. However, some concerns exist because it may place a selection pressure on the virus. Field and experimental data are provided which suggest that the use of TYLCD resistance in tomato crops might have contributed to the emergence of tomato yellow leaf curl virus in the TYLCD-associated virus population, a virus species that fits better in the resistant genotypes. Emergence of recombinant variants was observed during mixed infections of TYLCD-associated viruses in Ty-1 resistant plants, as already observed for susceptible tomatoes. Therefore, selection may be occurring for virus variants with novel genome combination to infect the resistant genotypes with this resistance gene. PMID:19735681

García-Andrés, S; Tomás, D M; Navas-Castillo, J; Moriones, E

2009-12-01

26

Note: Bemisia tabaci biotype B associated with tomato yellow leaf curl disease epidemics on rhodes Island, Greece  

Microsoft Academic Search

In 2006 an outbreak of tomato yellow leaf curl disease occurred in tomato crops on Rhodes Island, Greece. Diseased plants\\u000a were found to be infested with the B biotype of theBemisia tabaci (Gennadius) complex and greenhouse and open-field-grown tomato crops were infected withTomato yellow leaf curl virus (TYLCV) introduced from the Middle East. This is the first report of TYLCV

L. C. Papayiannis; J. K. Brown; M. Hadjistylli; N. I. Katis

2008-01-01

27

Bemisia tabaci – Tomato Yellow Leaf Curl Virus Interaction Causing Worldwide Epidemics  

Microsoft Academic Search

\\u000a \\u000a Tomato yellow leaf curl virus (TYLCV) is a begomovirus that threatens tomato production worldwide. TYLCV is transmitted in a circulative manner by the\\u000a whitefly Bemisia tabaci. Once ingested, TYLCV was detected in the insect midgut after 1 h, in the haemolymph after 1.5 h, and in the salivary glands\\u000a after 7 h. Whiteflies were able to infect tomato plants after

Henryk Czosnek; Murad Ghanim

28

Preparation and epitope characterization of monoclonal antibodies suitable for detection of Tomato yellow leaf curl virus  

Microsoft Academic Search

Tomato yellow leaf curl virus (TYLCV) is a begomovirus that seriously threatens tomato crops worldwide. Current immunodiagnostic methods for this pathogen\\u000a employ commercially produced mAbs raised against TYLCV. However, despite the existence of these mAbs, little information regarding\\u000a their characterization or strategy of production has been published. In addition, research on TYLCV would certainly benefit\\u000a were more mAbs available, thus

Leonardo J. Solmesky; Avi Zrachya; Galina Denisova; Yedidya Gafni; Jonathan M. Gershoni

2010-01-01

29

The Tomato Yellow Leaf Curl Virus Genome and Function of its Proteins  

Microsoft Academic Search

In the following, an overview on the genome organisation of tomato (yellow) leaf curl viruses will be presented. Also, a brief\\u000a description of the biological functions of the viral proteins will be given. The nomenclature including acronyms for some\\u000a TYLCV species was changed since their first description, in the following the ICTV-approved designations given in Stanley\\u000a et al. (2005) are

Bruno Gronenborn

30

Tomato yellow leaf curl virus (TYLCV) capsid protein (CP) subunit interactions: implications for viral assembly  

Microsoft Academic Search

Summary.  ?Tomato yellow leaf curl virus (TYLCV) capsid protein (CP) forms the capsule that encapsidates the viral genomic ssDNA. We have analyzed the homotypic interaction\\u000a capacity of full-length and mutated CP. We found that full-length CP interacts with itself. Truncation of the protein from\\u000a the C-terminal led to diminution of the self-interaction process. Also, the N-terminal region of the CP seemed

V. Hallan; Y. Gafni

2001-01-01

31

Molecular characterization and infectivity of Papaya leaf curl China virus infecting tomato in China*  

PubMed Central

Papaya leaf curl China virus (PaLCuCNV) was previously reported as a distinct begomovirus infecting papaya in southern China. Based on molecular diagnostic survey, 13 PaLCuCNV isolates were obtained from tomato plants showing leaf curl symptoms in Henan and Guangxi Provinces of China. Complete nucleotide sequences of 5 representative isolates (AJ558116, AJ558117, AJ704604, FN256260, and FN297834) were determined to be 2738–2751 nucleotides, which share 91.7%–97.9% sequence identities with PaLCuCNV isolate G2 (AJ558123). DNA-? was not found to be associated with PaLCuCNV isolates. To investigate the infectivity of PaLCuCNV, an infectious clone of PaLCuCNV-[CN:HeNZM1] was constructed and agro-inoculated into Nicotiana benthamiana, N. tabacum Samsun, N. glutinosa, Solanum lycopersicum and Petunia hybrida plants, which induced severe leaf curling and crinkling symptoms in these plants. Southern blot analysis and polymerase chain reaction (PCR) indicated a systemic infection of test plants by the agro-infectious clone. PMID:20104645

Zhang, Hui; Ma, Xin-ying; Qian, Ya-juan; Zhou, Xue-ping

2010-01-01

32

Identification of a distinct strain of cotton leaf curl Burewala virus.  

PubMed

Cotton leaf curl disease (CLCuD) is the major biotic limitation to cotton production in Pakistan and northwestern India. The disease is caused by various distinct viruses of the genus Begomovirus (family Geminiviridae) in association with a disease-specific betasatellite - cotton leaf curl Multan betasatellite (CLCuMB). Since 2001, when resistance to CLCuD in cotton was broken, only one virus was consistently identified in cotton exhibiting CLCuD symptoms in Punjab province (Pakistan) - cotton leaf curl Burewala virus (CLCuBuV). An analysis of all CLCuBuV isolates available in the databases showed these to represent only a single strain, based on currently applicable criteria. Virus and betasatellite clones were obtained from a leaf sample (isolate C49) collected from a CLCuD symptomatic cotton plant in Layyah district, Punjab province, in 2012. Analysis of the sequence of the betasatellite showed this to be an isolate of CLCuMB containing the recombinant fragment typical of this satellite post-resistance-breaking. The virus was shown it to be an isolate of CLCuBuV but to be distinct from all previously characterised isolates and to represent a distinct strain. In common with previous CLCuBuV isolates, the virus from C49 is a recombinant containing sequences derived from viruses of two species that were prevalent in cotton pre-resistance-breaking but with distinct recombination break sites. As was the case with the earlier CLCuBuV, the newly identified strain of CLCuBuV lacks an intact transcriptional activator protein. PMID:24838851

Shuja, Malik Nawaz; Briddon, Rob W; Tahir, Muhammad

2014-10-01

33

Evidence for Cytokinin Involvement in Rhizobium (IC3342)-Induced Leaf Curl Syndrome of Pigeonpea (Cajanus cajan Millsp.).  

PubMed

A uniquely abnormal shoot development (shoot tip-bending, leaf curling, release from apical dominance, and stunted growth) in pigeonpea (Cajanus cajan Millsp) induced by a nodulating Rhizobium strain, IC3342, is thought to be due to a hormonal imbalance. Amaranthus betacyanin bioassay indicated that xylem exudate and leaf extracts from pigeonpea plants with Rhizobium-induced leaf curl symptoms contained high concentrations of cytokinin relative to those in normal plants. Radioimmunoassay (RIA) of samples purified with high performance liquid chromatography revealed that zeatin riboside (ZR) and dihydrozeatin riboside (DZR) concentrations in xylem sap from plants with leaf curl symptoms were 7 to 9 times higher than those in the sap from symptomless, nodulated plants. The sap from symptomless plants nodulated by a Curl(-) mutant had ZR and DZR concentrations comparable to those in the normal plant sap. RIA indicated that the respective concentrations of zeatin and N(6)-isopenteny-ladenine in culture filtrates of the curl-inducing strain IC3342 were 26 and 8 times higher than those in filtrates of a related normal nodulating strain (ANU240). Gas chromatographic-mass spectrometric analyses revealed similar differences. Gene-specific hybridization and sequence comparisons failed to detect any homology of IC3342 DNA to Agrobacterium tumefaciens or Pseudomonas savastanoi genetic loci encoding enzymes involved in cytokinin biosynthesis. PMID:16668086

Upadhyaya, N M; Parker, C W; Letham, D S; Scott, K F; Dart, P J

1991-04-01

34

Evidence for Cytokinin Involvement in Rhizobium (IC3342)-Induced Leaf Curl Syndrome of Pigeonpea (Cajanus cajan Millsp.)  

PubMed Central

A uniquely abnormal shoot development (shoot tip-bending, leaf curling, release from apical dominance, and stunted growth) in pigeonpea (Cajanus cajan Millsp) induced by a nodulating Rhizobium strain, IC3342, is thought to be due to a hormonal imbalance. Amaranthus betacyanin bioassay indicated that xylem exudate and leaf extracts from pigeonpea plants with Rhizobium-induced leaf curl symptoms contained high concentrations of cytokinin relative to those in normal plants. Radioimmunoassay (RIA) of samples purified with high performance liquid chromatography revealed that zeatin riboside (ZR) and dihydrozeatin riboside (DZR) concentrations in xylem sap from plants with leaf curl symptoms were 7 to 9 times higher than those in the sap from symptomless, nodulated plants. The sap from symptomless plants nodulated by a Curl? mutant had ZR and DZR concentrations comparable to those in the normal plant sap. RIA indicated that the respective concentrations of zeatin and N6-isopenteny-ladenine in culture filtrates of the curl-inducing strain IC3342 were 26 and 8 times higher than those in filtrates of a related normal nodulating strain (ANU240). Gas chromatographic-mass spectrometric analyses revealed similar differences. Gene-specific hybridization and sequence comparisons failed to detect any homology of IC3342 DNA to Agrobacterium tumefaciens or Pseudomonas savastanoi genetic loci encoding enzymes involved in cytokinin biosynthesis. PMID:16668086

Upadhyaya, Narayana M.; Parker, C. William; Letham, David S.; Scott, Kieran F.; Dart, Peter J.

1991-01-01

35

First record of tomato yellow leaf curl Sardinia virus (TYLCSV) on pepper in Italy.  

PubMed

During a survey in summer 2007, a disease of pepper (Capsicum annuum) under plastic tunnels was observed in Policoro (Matera), on the Ionic coast of Basilicata Region, with a disease incidence in some cases of more than 50%. Affected cultivars were Eppo and Almund (S Et G). The diseased plants exhibited light mosaic or mottling, leaf distortion, interveinal and marginal leaf chlorosis, upward curling of leaf margins of older leaves. The causal pathogen was suspected to be a begomovirus due to the large population of the whitefly Bemisia tabaci observed on the crop. Detection assays for Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV) were used. In DAS-ELISA, positive results (178 plants resulted positive over 200 symptomatic plants assayed) were obtained using a "broad-spectrum" reagent combination (distributed by Bioreba AG) detecting TYLCV, TYLCSV, and other begamoviruses. A couple of synthetic oligonucleotides allowing the amplification of the whole coat protein (CP) gene of TYLCSV and TYLCV was used for PCR of ELISA positive samples in order to perform the molecular characterisation of the viral isolate responsible of the disease. RFLP analysis performed on the PCR product, 1008 bp long, showed the presence of only TYLCSV in the infected pepper plants. The same couple of primers allowed the detection of the virus also in symptomless pepper plants. To test whitefly transmission, adults of B. tabaci allowed to feed on naturally infected pepper plants were transferred on 10 healthy Eppo pepper seedlings (15 whiteflies/plant). Insects were killed 2 days later using an insecticide. Twenty days post exposition 10 plants/10 resulted positive in ELISA, and showed the same symptoms observed in natural infection. TYLCSV was not reported before on pepper in the surveyed area, but it was recorded with severe outbreaks on tomato, both in protected and in open field crops. This species was probably the primary source of infection from which subsequent diffusion by way of the vector B. tabaci followed on pepper. To our knowledge this is the first time that a natural infection of TYLCSV on pepper is recorded in Italy, with serious implications for the epidemiology of TYLCSV in our country. PMID:19226766

Fanigliulo, A; Pacella, R; Comes, S; Crescenzi, A

2008-01-01

36

Regional Changes in the Sequence of Cotton Leaf Curl Multan Betasatellite  

PubMed Central

Cotton leaf curl disease (CLCuD) in Pakistan and northwestern India is caused by monopartite begomoviruses in association with an essential, disease-specific satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Following a recent upsurge in CLCuD problems in Sindh province (southern Pakistan), sequences of clones of CLCuMB were obtained from Sindh and Punjab province (central Pakistan), where CLCuD has been a problem since the mid-1980s. The sequences were compared to all sequences of CLCuMB available in the databases. Analysis of the sequences shows extensive sequence variation in CLCuMB, most likely resulting from recombination. The range of sequence variants differ between Sindh, the Punjab and northwestern India. The possible significance of the findings with respect to movement of the CLCuD between the three regions is discussed. Additionally, the lack of sequence variation within the only coding sequence of CLCuMB suggests that the betasatellite is not involved in resistance breaking which became a problem after 2001 in the Punjab and subsequently also in northwestern India. PMID:24859342

Akhtar, Sohail; Tahir, Muhammad Nouman; Baloch, Ghulam Rasool; Javaid, Shaista; Khan, Ali Qaiser; Amin, Imran; Briddon, Rob W.; Mansoor, Shahid

2014-01-01

37

Lamium amplexicaule (Lamiaceae): a weed reservoir for tomato yellow leaf curl virus (TYLCV) in Korea.  

PubMed

After the first identification of tomato yellow leaf curl virus (TYLCV) in the southern part of Korea in 2008, TYLCV has rapidly spread to tomato farms in most regions of Korea. From 2008 to 2010, a survey of natural weed hosts that could be reservoirs of TYLCV was performed in major tomato production areas of Korea. About 530 samples were collected and identified as belonging to 25 species from 11 families. PCR and Southern hybridization were used to detect TYLCV in samples, and replicating forms of TYLCV DNA were detected in three species (Achyranthes bidentata, Lamium amplexicaule, and Veronica persica) by Southern hybridization. TYLCV transmission mediated by Bemisia tabaci from TYLCV-infected tomato plants to L. amplexicaule was confirmed, and TYLCV-infected L. amplexicaule showed symptoms such as yellowing, stunting, and leaf curling. TYLCV from infected L. amplexicaule was also transmitted to healthy tomato and L. amplexicaule plants by B. tabaci. The rate of infection of L. amplexicaule by TYLCV was similar to that of tomato. This report is the first to show that L. amplexicaule is a reservoir weed host for TYLCV. PMID:24327090

Kil, Eui-Joon; Park, Jungan; Lee, Hyejung; Kim, Jaedeok; Choi, Hong-Soo; Lee, Kyeong-Yeoll; Kim, Chang-Seok; Lee, Sukchan

2014-06-01

38

Molecular Characterization of Tomato Leaf Curl China Virus, Infecting Tomato Plants in China, and Functional Analyses of Its Associated Betasatellite?†  

PubMed Central

A novel tomato-infecting begomovirus from Guangxi province, China, was identified and characterized, for which the name Tomato leaf curl China virus (ToLCCNV) was proposed. Phylogenetic and recombination analyses of the virus genomic sequences suggested that ToLCCNV may have arisen by recombination among Tomato leaf curl Vietnam virus (ToLCVV), Tomato leaf curl Gujarat virus (ToLCGV), and an unknown virus. A betasatellite molecule was found to be associated with ToLCCNV (ToLCCNB), and its complete nucleotide sequences were determined. Infectious clones of ToLCCNV and ToLCCNB were constructed and then used for agro-inoculation of plants; ToLCCNV alone infected Nicotiana benthamiana, Nicotiana glutinosa, Petunia hybrida, and Solanum lycopersicum plants, but no symptoms were induced. ToLCCNB was required for induction of leaf curl disease in these hosts. The ?C1 protein of ToLCCNB was identified as a suppressor of RNA silencing and accumulated primarily in the nucleus. Deletion mutagenesis of ?C1 showed that the central part of ?C1 (amino acids 44 to 74) was responsible for both the suppressor activity and nuclear localization. PMID:21378048

Yang, Xiuling; Guo, Wei; Ma, Xinying; An, Qianli; Zhou, Xueping

2011-01-01

39

Cotton leaf curl Multan betasatellite as a plant gene delivery vector trans-activated by taxonomically diverse geminiviruses.  

PubMed

Cotton leaf curl Multan betasatellite (CLCuMB) replicates in tobacco, tomato and datura plants in the presence of the helper viruses tomato leaf curl virus-Australia, Iranian isolates of tomato yellow leaf curl virus, tomato leaf curl Karnataka virus, and beet severe curly top virus (BSCTV). Infectious recombinant CLCuMB constructs were made in which segments of either the CaMV 35S or the petunia ChsA promoter replaced the CLCuMB ?C1 ORF, and these were designated pBin??C1-35S and pBin??C1-ChsA, respectively. Inoculation of tobacco plants containing a functional 35S-GUS transgene with pBin??C1-35S, and normal petunia plants with pBin??C1-ChsA, in the presence of helper viruses resulted in silencing of GUS and ChsA activities in transgenic tobacco and non-transgenic petunia plants, respectively. Replication of CLCuMB with different geminiviruses, especially BSCTV, a curtovirus with a broad host range, makes it a valuable gene delivery vector to the large number of host plant species of geminiviruses that support CLCuMB. PMID:22476203

Kharazmi, S; Behjatnia, S A A; Hamzehzarghani, H; Niazi, A

2012-07-01

40

Rapid Spread of Tomato Yellow Leaf Curl Virus in China Is Aided Differentially by Two Invasive Whiteflies  

Microsoft Academic Search

BackgroundTomato yellow leaf curl virus (TYLCV) was introduced into China in 2006, approximately 10 years after the introduction of an invasive whitefly, Bemisia tabaci (Genn.) B biotype. Even so the distribution and prevalence of TYLCV remained limited, and the economic damage was minimal. Following the introduction of Q biotype into China in 2003, the prevalence and spread of TYLCV started

Huipeng Pan; Dong Chu; Wenqian Yan; Qi Su; Baiming Liu; Shaoli Wang; Qingjun Wu; Wen Xie; Xiaoguo Jiao; Rumei Li; Nina Yang; Xin Yang; Baoyun Xu; Judith K. Brown; Xuguo Zhou; Youjun Zhang

2012-01-01

41

Evidence for Transovarial Transmission of Tomato Yellow Leaf Curl Virus by Its Vector, the Whitefly Bemisia tabaci  

Microsoft Academic Search

The whiteflyBemisia tabaciis the only vector of the tomato yellow leaf curl geminivirus (TYLCV). The insect transmits the virus in a persistent-circulative manner. TYLCV DNA was detected by polymerase chain reaction and by Southern blot hybridization in progeny (eggs, first and second instars, adults) of single viruliferous whiteflies that developed on eggplant or on cotton (two TYLCV nonhost plants). Furthermore,

Murad Ghanim; Shai Morin; Muhammad Zeidan; Henryk Czosnek

1998-01-01

42

MOLECULAR IDENTIFICATION AND THE COMPLETE NUCLEOTIDE SEQUENCE OF A TOMATO YELLOW LEAF CURL VIRUS ISOLATE FROM TURKEY  

Microsoft Academic Search

SUMMARY Tomato yellow leaf curl disease (TYLCD) threatens the production of tomatoes both in Turkey and other tomato-growing areas of the world. The disease is caused by several virus species belonging to the genus Bego- movirus, family Geminiviridae that are transmitted by the whitefly Bemisia tabaci. There has been no previous information about which virus species\\/strains occur in tomatoes with

G. Köklü; A. Rojas; A. Kvarnheden; Carretera Norte

2006-01-01

43

Inhibition of Tomato Yellow Leaf Curl Virus (TYLCV) using whey proteins  

PubMed Central

The antiviral activity of native and esterified whey proteins fractions (?-lactalbumin, ?-lactoglobulin, and lactoferrin) was studied to inhibit tomato yellow leaf curl virus (TYLCV) on infected tomato plants. Whey proteins fractions and their esterified derivatives were sprayed into TYLCV-infected plants. Samples were collected from infected leaves before treatment, 7 and 15 days after treatment for DNA and molecular hybridization analysis. The most evident inhibition of virus replication was observed after 7 and 15 days using ?-lactoferrin and ?-lactalbumin, respectively. Native and esterified lactoferrin showed complete inhibition after 7 days. On the other hand, native ?-lactoglobulin showed inhibition after 7 and 15 days whereas esterified ?-lactoglobulin was comparatively more effective after 7 days. The relative amount of viral DNA was less affected by the esterified ?-lactalbumin whereas native ?-lactalbumin inhibited virus replication completely after 15 days. These results indicate that native or modified whey proteins fractions can be used for controlling the TYLCV-infected plants. PMID:20128897

2010-01-01

44

Within-host dynamics of the emergence of Tomato yellow leaf curl virus recombinants.  

PubMed

Tomato yellow leaf curl virus (TYLCV) is a highly damaging begomovirus native to the Middle East. TYLCV has recently spread worldwide, recombining with other begomoviruses. Recent analysis of mixed infections between TYLCV and Tomato leaf curl Comoros begomovirus (ToLCKMV) has shown that, although natural selection preserves certain co-evolved intra-genomic interactions, numerous and diverse recombinants are produced at 120 days post-inoculation (dpi), and recombinant populations from different tomato plants are very divergent. Here, we investigate the population dynamics that lead to such patterns in tomato plants co-infected with TYLCV and ToLCKMV either by agro-inoculation or using the natural whitefly vector Bemisia tabaci. We monitored the frequency of parental and recombinant genotypes independently in 35 plants between 18 and 330 dpi and identified 177 recombinants isolated at different times. Recombinants were detected from 18 dpi and their frequency increased over time to reach about 50% at 150 dpi regardless of the inoculation method. The distribution of breakpoints detected on 96 fully sequenced recombinants was consistent with a continuous generation of new recombinants as well as random and deterministic effects in their maintenance. A severe population bottleneck of around 10 genomes was estimated during early systemic infection-a phenomenon that could account partially for the heterogeneity in recombinant patterns observed among plants. The detection of the same recombinant genome in six of the thirteen plants analysed beyond 30 dpi supported the influence of selection on observed recombination patterns. Moreover, a highly virulent recombinant genotype dominating virus populations within one plant has, apparently, the potential to be maintained in the natural population according to its infectivity, within-host accumulation, and transmission efficiency - all of which were similar or intermediate to those of the parent genotypes. Our results anticipate the outcomes of natural encounters between TYLCV and ToLCKMV. PMID:23472190

Urbino, Cica; Gutiérrez, Serafin; Antolik, Anna; Bouazza, Nabila; Doumayrou, Juliette; Granier, Martine; Martin, Darren P; Peterschmitt, Michel

2013-01-01

45

Tomato leaf curl geminivirus associated with cantaloupe yellow leaf disease in Thailand  

Microsoft Academic Search

Geminivirus associated with yellow leaf disease of cantaloupe plants was detected using polymerase chain reaction (PCR) with geminivirus-specific degenerate primers which anneal within the AC1 ORF (replication initiator protein gene) and the AV1 ORF (coat protein gene). A DNA fragment of 1.2 kbp was amplified, cloned and sequenced. The 32-base stem loop region was found in the amplified fragment. This

Kloyjai Samretwanich; Pissawan Chiemsombat; Kruapan Kittipakorn; Masato Ikegami

2000-01-01

46

Tomato yellow leaf curl virus in Australia: distribution, detection and discovery of naturally occurring defective DNA molecules  

Microsoft Academic Search

Tomato yellow leaf curl virus (TYLCV) was detected for the first time in Australia in March 2006 in field-grown tomatoes in Brisbane, Queensland. Surveys\\u000a showed that the virus was confined to south-east Queensland. Virus transmission studies carried out using Bemisia tabaci (B biotype) verified that resistant tomato lines containing the Ty-1 or Ty-5 genes displayed tolerance to infection by TYLCV

S. L. Van Brunschot; D. M. Persley; A. D. W. Geering; P. R. Campbell; J. E. Thomas

2010-01-01

47

Complete nucleotide sequence of Iranian tomato yellow leaf curl virus isolate: further evidence for natural recombination amongst begomoviruses  

Microsoft Academic Search

Summary. Complete nucleotide sequence of the Iranian strain of tomato yellow leaf curl virus (TYLCV-IR) was determined and compared with some begomoviruses. The complete sequence of TYLCV-IR clustered together with TYLCV and TYLCV-MId from Israel. A similar relationship holds when the deduced amino acid sequences of V1, V2, C2 and C3 and nucleotide sequences of IR, and RIR were compared.

K. Bananej; A. Kheyr-Pour; G. Hosseini Salekdeh; A. Ahoonmanesh

2004-01-01

48

Infection of tomato by the tomato yellow leaf curl virus: susceptibility to infection, symptom development, and accumulation of viral DNA  

Microsoft Academic Search

Summary Symptom development in tomato plants following whitefly-mediated inoculation with tomato yellow leaf curl virus (TYLCV) was related to the occurrence of viral DNA using a specific DNA probe. Although disease symptoms were first observed 15 days post-inoculation, viral DNA could be detected 7 days earlier. TYLCV-DNA concentrations reached an optimum 4 days before symptoms appeared. The highest concentrations of

R. Ber; N. Navot; D. Zamir; Y. Antignus; S. Cohen; H. Czosnek

1990-01-01

49

Short Communication Tomato yellow leaf curl Sardinia virus can overcome transgene-mediated RNA silencing of two essential viral genes  

Microsoft Academic Search

To evaluate RNA silencing for the control of geminivirus infection, two classes of post-transcriptionally silenced (PTS) plants were tested using Tomato yellow leaf curl Sardiniavirus(TYLCSV)Rep-210-transgenic plants,asense6antisensehybridandtwomulticopy sense lines. In both classes, PTS plants accumulated low or undetectable amounts of Rep-210 protein and mRNA but high amounts of Rep-210 small interfering RNAs. PTS plants were susceptible to TYLCSV when challenged by

Emanuela Noris; Alessandra Lucioli; Raffaela Tavazza; Piero Caciagli; Gian Paolo Accotto; Mario Tavazza

50

Phylogenetic analysis and inflow route of Tomato yellow leaf curl virus (TYLCV) and Bemisia tabaci in Korea  

Microsoft Academic Search

Tomato yellow leaf curl virus (TYLCV) is a member of the genus Begomovirus of the family Geminiviridae, members of which are characterized by closed circular single-stranded DNA genomes of 2.7-2.8 kb in length, and include viruses\\u000a transmitted by the Bemisia tabaci whitefly. No reports of TYLCV in Korea are available prior to 2008, after which TYLCV spread rapidly to most

Hyejung Lee; Woogeun Song; Hae-Ryun Kwak; Jae-deok Kim; Chung-Kyoon Auh; Dae-Hyun Kim; Kyeong-yeoll Lee; Sukchan Lee; Hong-Soo Choi

2010-01-01

51

Relationships of the Sardinian isolate of tomato yellow leaf curl geminivirus with its whitefly vector Bemisia tabaci Gen  

Microsoft Academic Search

Relationships of an Italian isolate of tomato yellow leaf curl geminivirus from Sardinia (TYLCV-S) with its whitefly vectorBemisia tabaci were studied by means of experimental transmissions from tomato to tomato plants. TYLCV-S was confirmed to be transmitted in a persistent, circulative manner. The minimum latent period in the vector was between 17 and 20 h from the beginning of the

P. Caciagli; D. Bosco; Lina Al-Bitar

1995-01-01

52

Detection of Ageratum enation virus from cat’s whiskers ( Cleome gynandra L.) with leaf curl symptoms in India  

Microsoft Academic Search

An association of a begomovirus with leaf curl symptoms on Cleome gynandra was detected using a polymerase chain reaction (PCR) with begomovirus-specific primers. Further, the complete DNA-A of the\\u000a begomovirus was cloned and sequenced. BLAST analysis of the sequence data revealed 92–99% identities and close relationships\\u000a with several isolates of Ageratum enation virus (AgEV); therefore, we identified the virus associated

S. K. Raj; S. K. Snehi; M. S. Khan; A. K. Tiwari; G. P. Rao

2010-01-01

53

Female-Biased Symbionts and Tomato Yellow Leaf Curl Virus Infections in Bemisia tabaci  

PubMed Central

The female-biased infection of facultative symbionts has been found in Bemisia tabaci; however, whether there are any differences in tomato yellow leaf curl virus (TYLCV) and obligate symbiont infection rates between females and males is unknown. Determining whether such differences exist would be very important for understanding the spread of the plant virus and of the symbionts. We compared both symbiont infection types, including obligate and facultative symbionts, and the rates of TYLCV infection in both sexes in five field populations from Jiangsu Province, China. The obligate symbiont Portiera aleyrodidarum was not found in every whitefly tested. In all tested populations, more females than males were found to harbor P. aleyrodidarum; and more females than males also harbored Hamiltonella defense, the most common facultative symbiont as well as Cardinium. In addition to female-biased symbiont infections, there were also female-biased TYLCV infections, and the infection frequencies of this plant virus in females were higher than those in males. Taken together, these results suggested that both the female-biased symbiont infections and female-biased TYLCV infections promoted the rapid spread of TYLCV in China. PMID:24465416

Guo, Huifang; Qu, Yufeng; Liu, Xiangdong; Zhong, Wanfang; Fang, Jichao

2014-01-01

54

Tomato yellow leaf curl virus alters the host preferences of its vector Bemisia tabaci  

PubMed Central

Bemisia tabaci, the whitefly vector of Tomato yellow leaf curl virus (TYLCV), seriously reduces tomato production and quality. Here, we report the first evidence that infection by TYLCV alters the host preferences of invasive B. tabaci B (Middle East-Minor Asia 1) and Q (Mediterranean genetic group), in which TYLCV-free B. tabaci Q preferred to settle on TYLCV-infected tomato plants over healthy ones. TYLCV-free B. tabaci B, however, preferred healthy tomato plants to TYLCV-infected plants. In contrast, TYLCV-infected B. tabaci, either B or Q, did not exhibit a preference between TYLCV-infected and TYLCV-free tomato plants. Based on gas chromatography-mass spectrometry (GCMS)analysis of plant terpene volatiles, significantly more ?-myrcene, thymene, ?-phellandrene, caryophyllene, (+)-4-carene, and ?-humulene were released from the TYLCV-free tomato plants than from the TYLCV-infected ones. The results indicate TYLCV can alter the host preferences of its vector Bemisia tabaci B and Q. PMID:24096821

Fang, Yong; Jiao, Xiaoguo; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Shi, Xiaobin; Chen, Gong; Su, Qi; Yang, Xin; Pan, Huipeng; Zhang, Youjun

2013-01-01

55

Bemisia tabaci Q carrying tomato yellow leaf curl virus strongly suppresses host plant defenses  

PubMed Central

The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous Q-infested plants than on control plants. The longevity of viruliferous B showed the same phenomenon. At 1 d infestion, the jasmonic acid content in leaves noninfested and in leaves infested with nonviruliferous B, nonviruliferous Q, viruliferous B and viruliferous Q was 407.000, 281.333, 301.333, 266.667 and 134.000?ng/g FW, respectively. The JA content was lowest in viruliferous Q-infested leaves. The proteinase inhibitor activity and expression of JA-related upstream gene LOX and downstream gene PI II showed the same trend. The substantial suppression of host defenses by Q carrying TYLCV probably enhances the spread of Q and TYLCV in China. PMID:24912756

Shi, Xiaobin; Pan, Huipeng; Zhang, Hongyi; Jiao, Xiaoguo; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Fang, Yong; Chen, Gong; Zhou, Xuguo; Zhang, Youjun

2014-01-01

56

Bemisia tabaci Q carrying tomato yellow leaf curl virus strongly suppresses host plant defenses.  

PubMed

The concurrence of tomato yellow leaf curl virus (TYLCV) with the spread of its vector Bemisia tabaci Q rather than B in China suggests a more mutualistic relationship between TYLCV and Q. Here, we investigated the hypothesis that viruliferous B and Q have different effects on plant defenses. We found the fecundity of nonviruliferous B, nonviruliferous Q, viruliferous Q and viruliferous B was 11.080, 12.060, 10.760, and 11.220 respectively on plants previously attacked by the other biotype, however, on their respective noninfested control leaves fecundity was 12.000, 10.880, 9.760, and 8.020 respectively. Only viruliferous B had higher fecundity on viruliferous Q-infested plants than on control plants. The longevity of viruliferous B showed the same phenomenon. At 1 d infestion, the jasmonic acid content in leaves noninfested and in leaves infested with nonviruliferous B, nonviruliferous Q, viruliferous B and viruliferous Q was 407.000, 281.333, 301.333, 266.667 and 134.000?ng/g FW, respectively. The JA content was lowest in viruliferous Q-infested leaves. The proteinase inhibitor activity and expression of JA-related upstream gene LOX and downstream gene PI II showed the same trend. The substantial suppression of host defenses by Q carrying TYLCV probably enhances the spread of Q and TYLCV in China. PMID:24912756

Shi, Xiaobin; Pan, Huipeng; Zhang, Hongyi; Jiao, Xiaoguo; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Fang, Yong; Chen, Gong; Zhou, Xuguo; Zhang, Youjun

2014-01-01

57

Safety assessment of leaf curl virus resistant tomato developed using viral derived sequences.  

PubMed

Genetic engineering of food crops has significantly influenced the agricultural productivity over the past two decades. It has proved a valuable tool, offering crops with higher yields, improved nutritional quality, resistance against pesticides, herbicides and tolerance against abiotic stresses. However, the safety assessment of genetically engineered (GE) crops is prerequisite before introduction into human food chain. The present study was aimed to assess the toxicity and allergenicity of leaf curl virus resistant GE tomato compared to its wild-type species. Balb/c mice fed with genetically engineered or wild-type tomato did not show significant differences in growth, body weight (P > 0.05) and food consumption when compared with control mice. Values for serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase, urea and cholesterol were comparable in GE and wild-type tomato fed mice. Mice immunized with GE or wild-type tomato extract showed low IgE response. Lung histology of ovalbumin fed mice showed bronchoconstriction with eosinophilic infiltration whereas GE or wild-type tomato showed no cellular infiltration with normal airways. Genetically engineered and wild-type tomato sensitized mice demonstrated similar IL-4 release in splenic cell culture supernatant. GE and wild tomato extract on ELISA showed comparable IgE binding (P > 0.05) with food allergic patients' sera. In conclusion, genetically engineered tomato showed no toxicity in mice and allergenicity is similar to the wild-type tomato. PMID:19415521

Singh, Abinav K; Praveen, Shelly; Singh, Bhanu P; Varma, Anupam; Arora, Naveen

2009-12-01

58

Cotton leaf curl disease - an emerging threat to cotton production worldwide.  

PubMed

Cotton leaf curl disease (CLCuD) is a serious disease of cotton which has characteristic symptoms, the most unusual of which is the formation of leaf-like enations on the undersides of leaves. The disease is caused by whitefly-transmitted geminiviruses (family Geminiviridae, genus Begomovirus) in association with specific, symptom-modulating satellites (betasatellites) and an evolutionarily distinct group of satellite-like molecules known as alphasatellites. CLCuD occurs across Africa as well as in Pakistan and north-western India. Over the past 25 years, Pakistan and India have experienced two epidemics of the disease, the most recent of which involved a virus and satellite that are resistance breaking. Loss of this conventional host-plant resistance, which saved the cotton growers from ruin in the late 1990s, leaves farmers with only relatively poor host plant tolerance to counter the extensive losses the disease causes. There has always been the fear that CLCuD could spread from the relatively limited geographical range it encompasses at present to other cotton-growing areas of the world where, although the disease is not present, the environmental conditions are suitable for its establishment and the whitefly vector occurs. Unfortunately recent events have shown this fear to be well founded, with CLCuD making its first appearance in China. Here, we outline recent advances made in understanding the molecular biology of the components of the disease complex, their interactions with host plants, as well as efforts being made to control CLCuD. PMID:23324471

Sattar, M Naeem; Kvarnheden, Anders; Saeed, Muhammad; Briddon, Rob W

2013-04-01

59

The Spread of Tomato Yellow Leaf Curl Virus from the Middle East to the World  

PubMed Central

The ongoing global spread of Tomato yellow leaf curl virus (TYLCV; Genus Begomovirus, Family Geminiviridae) represents a serious looming threat to tomato production in all temperate parts of the world. Whereas determining where and when TYLCV movements have occurred could help curtail its spread and prevent future movements of related viruses, determining the consequences of past TYLCV movements could reveal the ecological and economic risks associated with similar viral invasions. Towards this end we applied Bayesian phylogeographic inference and recombination analyses to available TYLCV sequences (including those of 15 new Iranian full TYLCV genomes) and reconstructed a plausible history of TYLCV's diversification and movements throughout the world. In agreement with historical accounts, our results suggest that the first TYLCVs most probably arose somewhere in the Middle East between the 1930s and 1950s (with 95% highest probability density intervals 1905–1972) and that the global spread of TYLCV only began in the 1980s after the evolution of the TYLCV-Mld and -IL strains. Despite the global distribution of TYLCV we found no convincing evidence anywhere other than the Middle East and the Western Mediterranean of epidemiologically relevant TYLCV variants arising through recombination. Although the region around Iran is both the center of present day TYLCV diversity and the site of the most intensive ongoing TYLCV evolution, the evidence indicates that the region is epidemiologically isolated, which suggests that novel TYLCV variants found there are probably not direct global threats. We instead identify the Mediterranean basin as the main launch-pad of global TYLCV movements. PMID:21060815

Lefeuvre, Pierre; Martin, Darren P.; Harkins, Gordon; Lemey, Philippe; Gray, Alistair J. A.; Meredith, Sandra; Lakay, Francisco; Monjane, Adérito; Lett, Jean-Michel; Varsani, Arvind; Heydarnejad, Jahangir

2010-01-01

60

Severe outbreak of tomato yellow leaf curl Sardinia virus on pepper in southern Italy.  

PubMed

During summer and autumn 2008 a severe outbreak of pepper leaf curl disease (PLCD) was observed in pepper crops under plastic tunnels in the ionic coast of Basilicata region. Its incidence reached, in some cases, values close to 50%. The beginning of infections was recorded along the perimeter of the tunnels, where it reached a percentage of almost 100%. The infection then progressively spread towards the central areas of the greenhouses. Large populations of whiteflies, identificated as Bemisia tabaci, were observed on the infected crops. Detection assays for TYLCSV and TYLCV were performed in order to ascertain the etiologic agent: 190 symptomatic samples were collected from different fields and assayed in DAS-ELISA using a broad-spectrum reagent combination (distributed by Bioreba AG) detecting TYLCV, TYLCSV and other Begamoviruses: of these, 176 samples resulted positive. In order to discriminate between TYLCSV, TYLCV or any other Begamovirus, 15 positive samples were analyzed by PCR using a couple of synthetic oligonucleotides allowing the amplification of the whole coat protein (CP) gene. RFLP analysis performed on the PCR product, 1008 bp long, showed the presence of only TYLCSV in all assayed samples. The molecular characterization performed by phylogenetic analysis of the sequenced coat protein gene revealed that the isolate shares a similarity of about 97% with the corresponding sequence of a tomato TYLCSV isolate from Sicily (Z28390) and is almost identical with the pepper isolate CAB-It recovered in the same area in 2007 (TYLCSV was first recorded on pepper in Italy in 2007 in Policoro-MT, Fanigliulo et al., 2008. Comm. Appl. Biol. Sci, Ghent University, 73/2, 2008), indicating that there is a very low variability in TYLCSV population in the surveyed area. The further diffusion of PLCD and its hazard has to be connected with the presence of wide tomato cultivations, of weed hosts alternative to pepper (Solanum nigrum, Datura stramonium, Sonchus asper, Cardaria draba and Abutilon theophrasti) and with the strong presence of the vector B. tabaci of the B biotype, more efficient than Q biotype in the virus transmission, and able to feed and reproduce on peppers as well as on tomatoes. PMID:20222578

Comes, Soccorsa; Fanigliulo, Angela; Pacella, Rosa; Crescenzi, Aniello

2009-01-01

61

Genetic structure and evolution of natural populations of viruses causing the tomato yellow leaf curl disease in Spain.  

PubMed

The population structure and genetic variation of two begomoviruses: tomato yellow leaf curl Sardinia virus (TYLCSV) and tomato yellow leaf curl virus (TYLCV) in tomato crops of Spain were studied from 1997 until 2001. Restriction digestion of a genomic region comprised of the CP coat protein gene (CPR) of 358 TYLC virus isolates enabled us to classify them into 14 haplotypes. Nucleotide sequences of two genomic regions: CPR, and the surrounding intergenic region (SIR) were determined for at least two isolates per haplotype. SIR was more variable than CPR and showed multiple recombination events whereas no recombination was detected within CPR. In all geographic regions except Murcia, the population was, or evolved to be composed of one predominant haplotype with a low genetic diversity (<0.0180). In Murcia, two successive changes of the predominant haplotype were observed in the best studied population. Phylogenetic analysis showed that the TYLCSV sequences determined clustered with sequences obtained from the GenBank of other TYLCSV Spanish isolates which were clearly separated from TYLCSV Italian isolates. Most of our TYLCV sequences were similar to those of isolates from Japan and Portugal, and the sequences obtained from TYLCV isolates from the Canary island of Lanzarote were similar to those of Caribbean TYLCV isolates. PMID:17524509

Font, María Isabel; Rubio, Luis; Martínez-Culebras, Pedro Vicente; Jordá, Concepción

2007-09-01

62

Screening low fire blight susceptible Crataegus species for host suitability to hawthorn leaf-curling aphids (Dysaphis spp.).  

PubMed

The group of hawthorn leaf-curling aphids (Dysaphis spp.) hosted by the common hawthorn Crataegus monogyna Jacq. may play an important role in the biological control of the rosy apple aphid, Dysaphis plantaginea (Passerini), by increasing reproduction opportunities for the indigenous hymenopteran parasitoid Ephedrus persicae Froggatt. Unfortunately, most fruitgrowers hesitate to introduce the common hawthorn in their orchards because they fear fire blight infections which may be transmitted by this highly susceptible hawthron species. This potential hazard led us to investigate the suitability to leaf-curling aphids of alternative Crataegus species. As representative for these closely-related aphids, the species Dysaphis apiifolia petroselini (Börner) was used in the trials. Ten Crataegus species characterized by their very low susceptibility to fire blight were examined from two angles. Firstly, aphid sexuals were introduced in autumn onto the different species to verify whether egg laying could take place. Secondly, the development of fundatrices and gall formation were followed the next spring. Although eggs and mature fundatrices could be obtained on almost all species, no fundatrice-hosting galls were recorded in spring. The possible causes of these negative results with respect to the geographical origin of the particular Crataegus species involved in this work are discussed. PMID:12696414

Bribosia, E; Bylemans, D; Van Impe, G; Migon, M

2002-01-01

63

Genome organization of Tobacco leaf curl Zimbabwe virus, a new, distinct monopartite begomovirus associated with subgenomic defective DNA molecules.  

PubMed

The complete DNA A of the begomovirus Tobacco leaf curl Zimbabwe virus (TbLCZWV) was sequenced: it comprises 2767 nucleotides with six major open reading frames encoding proteins with molecular masses greater than 9 kDa. Full-length TbLCZWV DNA A tandem dimers, cloned in binary vectors (pBin19 and pBI121) and transformed into Agrobacterium tumefaciens, were systemically infectious upon agroinoculation of tobacco and tomato. Efforts to identify a DNA B component were unsuccessful. These findings suggest that TbLCZWV is a new member of the monopartite group of begomoviruses. Phylogenetic analysis identified TbLCZWV as a distinct begomovirus with its closest relative being Chayote mosaic virus. Abutting primer PCR amplified ca. 1300 bp molecules, and cloning and sequencing of two of these molecules revealed them to be subgenomic defective DNA molecules originating from TbLCZWV DNA A. Variable symptom severity associated with tobacco leaf curl disease and TbLCZWV is discussed. PMID:11714987

Paximadis, M; Rey, M E

2001-12-01

64

Long-term association of tomato yellow leaf curl virus with its whitefly vector Bemisia tabaci: effect on the insect transmission capacity, longevity and fecundity  

Microsoft Academic Search

The association between tomato yellow leaf curl geminivirus (TYLCV, Israeli isolate) and its insect vector, the whitefly Bemisia tabaci, was investigated. Insects that emerged during a 24 h period were caged with TYLCV-infected plants for a 48 h ac- quisition access period, then with egg-plants - a TYLCV non-host - for the rest of their lives. While TYLCV DNA was

Galina Rubinstein; Henryk Czosnek

1997-01-01

65

Transmission of Tomato Yellow Leaf Curl Virus by two invasive biotypes and a Chinese indigenous biotype of the whitefly Bemisia tabaci  

Microsoft Academic Search

The global invasion of certain Bemisia tabaci biotypes provides opportunities to compare the competency of virus transmission between invasive and indigenous biotypes. Here we report on the acquisition, retention and transmission of Tomato Yellow Leaf Curl Virus (TYLCV) by the invasive B, Q and indigenous ZHJ2 biotypes of B. tabaci from Zhejiang, China. For all whitefly biotypes, TYLCV DNA was

Meng Li; Jian Hu; Fang-Cheng Xu; Shu-Sheng Liu

2010-01-01

66

Efficient Regeneration and Selection of Virus-free Sweetpotato Plants from Sweet Potato Leaf Curl Virus Infected Materials and Their Effects on Yields in Field Trials  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sweet potato leaf curl virus (SPLCV) is an emerging virus disease in sweetpotato (Ipomoea batata) in the U.S. The incidence of SPLCV infection on sweetpotato increased dramatically in recent years due to the explosion of whitefly, Bemisia tabaci (Gennadius) populations. Among several sweetpotato v...

67

Three-way interactions between the tomato plant, tomato yellow leaf curl virus, and Bemisia tabaci (Hemiptera: Aleyrodidae) facilitate virus spread.  

PubMed

Plant defense responses can greatly affect plant viruses and their herbivore vectors. The current article reports on plant defense responses involving jasmonic acid (JA), salicylic acid (SA), and proteinase inhibitor (PI) in the three-way interaction between tomato plants, tomato yellow leaf curl virus, and the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). The results showed that feeding by viruliferous B. tabaci increases the longevity and fecundity of nonviruliferous B. tabaci that subsequently feed on the same plant. Feeding by nonviruliferous B. tabaci alone suppressed plant defense responses involving JA and PI but induced responses involving SA. Feeding by viruliferous B. tabaci increased the suppression of plant defenses involving JA and PI but did not increase responses involving SA. These results indicate that the interactive effects of tomato yellow leaf curl virus and B. tabaci on plants increase vector fitness and virus transmission by reducing plant defense. PMID:25026648

Shi, Xiaobin; Pan, Huipeng; Xie, Wen; Jiao, Xiaoguo; Fang, Yong; Chen, Gong; Yang, Xin; Wu, Qingjun; Wang, L Shaoli; Zhang, Youjun

2014-06-01

68

Co-transmission of Tomato yellow leaf curl virus (TYLCV)Mld and TYLCV-IL by the whitefly Bemisia tabaci  

Microsoft Academic Search

The ability of the whitefly Bemisia tabaci to transmit two strains of Tomato yellow leaf curl virus, the Israel and Mild strains, was studied after serial transfers of individual whiteflies that were viruliferous for both\\u000a strains to tomato plants. After single whiteflies had successive acquisition feedings first on a single plant infected with\\u000a one strain and then on a plant

Jun Ohnishi; Toshio Kitamura; Fumihiro Terami; Ken-ichiro Honda

2011-01-01

69

Whiteflies ( Bemisia tabaci ) issued from eggs bombarded with infectious DNA clones of Tomato yellow leaf curl virus from Israel (TYLCV) are able to infect tomato plants  

Microsoft Academic Search

Summary.  ?We have reported previously that Tomato yellow leaf curl virus from Israel (TYLCV) penetrates the reproductive system of its vector, the whitefly Bemisia tabaci biotype B, and may be transmitted to progeny [9]. In order to mimic this phenomenon and to understand how TYLCV accompanies\\u000a the development of the insect, we have bombarded B. tabaci eggs with an infectious DNA

V. Goldman; H. Czosnek

2002-01-01

70

Virion Stability Is Important for the Circulative Transmission of Tomato Yellow Leaf Curl Sardinia Virus by Bemisia tabaci, but Virion Access to Salivary Glands Does Not Guarantee Transmissibility  

Microsoft Academic Search

The capsid protein (CP) of the monopartite begomovirus Tomato yellow leaf curl Sardinia virus (TYLCSV), family Geminiviridae, is indispensable for plant infection and vector transmission. A region between amino acids 129 and 152 is critical for virion assembly and insect transmissibility. Two previously described mutants, one with a double Q129P Q134H mutation (PNHD) and another with a further D152E change

Piero Caciagli; Vicente Medina Piles; Daniele Marian; Manuela Vecchiati; Vera Masenga; Giovanna Mason; Tania Falcioni; Emanuela Noris

2009-01-01

71

Amino Acids in the Capsid Protein of Tomato Yellow Leaf Curl Virus That Are Crucial for Systemic Infection, Particle Formation, and Insect Transmission  

Microsoft Academic Search

A functional capsid protein (CP) is essential for host plant infection and insect transmission in monopartite geminiviruses. We studied two defective genomic DNAs of tomato yellow leaf curl virus (TYLCV), Sic and SicRcv. Sic, cloned from a field-infected tomato, was not infectious, whereas SicRcv, which spontaneously originated from Sic, was infectious but not whitefly transmissible. A single amino acid change

E. NORIS; A. M. VAIRA; P. CACIAGLI; V. MASENGA; B. GRONENBORN; G. P. ACCOTTO

1998-01-01

72

A selective barrier in the midgut epithelial cell membrane of the nonvector whitefly Trialeurodes vaporariorum to Tomato yellow leaf curl virus uptake  

Microsoft Academic Search

We studied the presence of a potential transmission barrier that blocks Tomato yellow leaf curl virus in the nonvector greenhouse whitefly, Trialeurodes vaporariorum. Because T. vaporariorum can ingest and retain the virus after acquisition feeding on an infected plant, comparable to the vector whitefly Bemisia tabaci, circumstance evidence suggested that a transmission barrier presents at location(s) where the virus moves from the

Jun Ohnishi; Toshio Kitamura; Fumihiro Terami; Ken-ichiro Honda

2009-01-01

73

In vitro Cleavage and Joining at the Viral Origin of Replication by the Replication Initiator Protein of Tomato Yellow Leaf Curl Virus  

Microsoft Academic Search

Replication of the single-stranded DNA genome of geminiviruses occurs via a double-stranded intermediate that is subsequently used as a template for rolling-circle replication of the viral strand. Only one of the proteins encoded by the virus, here referred to as replication initiator protein (Rep protein), is indispensable for replication. We show that the Rep protein of tomato yellow leaf curl

Jurgen Laufs; Wolfgang Traut; Francoise Heyraud; Volker Matzeit; Stephen G. Rogers; Jeff Schell; Bruno Gronenborn

1995-01-01

74

Association of an Alphasatellite with Tomato Yellow Leaf Curl Virus and Ageratum Yellow Vein Virus in Japan is Suggestive of a Recent Introduction  

PubMed Central

Samples were collected in 2011 from tomato plants exhibiting typical tomato leaf curl disease symptoms in the vicinity of Komae, Japan. PCR mediated amplification, cloning and sequencing of all begomovirus components from two plants from different fields showed the plants to be infected by Tomato yellow leaf curl virus (TYLCV) and Ageratum yellow vein virus (AYVV). Both viruses have previously been shown to be present in Japan, although this is the first identification of AYVV on mainland Japan; the virus previously having been shown to be present on the Okinawa Islands. The plant harboring AYVV was also shown to contain the betasatellite Tomato leaf curl Java betasatellite (ToLCJaB), a satellite not previously shown to be present in Japan. No betasatellite was associated with the TYLCV infected tomato plants analyzed here, consistent with earlier findings for this virus in Japan. Surprisingly both plants were also found to harbor an alphasatellite; no alphasatellites having previously been reported from Japan. The alphasatellite associated with both viruses was shown to be Sida yellow vein China alphasatellite which has previously only been identified in the Yunnan Province of China and Nepal. The results suggest that further begomoviruses, and their associated satellites, are being introduced to Japan. The significance of these findings is discussed. PMID:24424499

Shahid, Muhammad Shafiq; Ikegami, Masato; Waheed, Abdul; Briddon, Rob W.; Natsuaki, Keiko T.

2014-01-01

75

Molecular variability and evolution of a natural population of tomato yellow leaf curl virus in Shanghai, China*  

PubMed Central

Tomato yellow leaf curl virus (TYLCV), belonging to the genus Begomovirus of the family Geminiviridae, is emerging as the most destructive pathogen of tomato plants. Since the first report of TYLCV in Shanghai, China in 2006, TYLCV has spread rapidly to 13 provinces or autonomous regions of China. In this study, the molecular variability and evolution of TYLCV were monitored in Shanghai from its first upsurge in 2006 until 2010. Full-length genomic sequences of 26 isolates were obtained by rolling circle amplification. Sequence analysis showed that the intergenic region was the most variable, with a mean mutation rate of 4.81×10?3 nucleotide substitutions per site per year. Genetic differentiation was found within isolates obtained from 2006, 2009, and 2010, though a linear increase in genetic diversity over time was not evident. Whilst significant parts of TYLCV genes were under negative selection, the C4 gene embedded entirely within the C1 gene had a tendency to undergo positive selection. Our results indicate that a mechanism of independent evolution of overlapping regions could apply to the natural population of TYLCV in Shanghai, China. PMID:24510706

Yang, Xiu-ling; Zhou, Meng-ning; Qian, Ya-juan; Xie, Yan; Zhou, Xue-ping

2014-01-01

76

Correlation of meteorological parameters and remotely sensed normalized difference vegetation index (NDVI) with cotton leaf curl virus (CLCV) in Multan  

NASA Astrophysics Data System (ADS)

Climate change and weather has a profound effect on the spread of Cotton Leaf Curl Virus (CLCV) which is transmitted by whitefly. Climate change is altering temperature and precipitation patterns, resulting in the shift of some insect/pest from small population to large population thus effecting crops yield. To find out the relationship between the weather conditions, outburst of CLCV and changes in Normalized Difference Vegetation Index (NDVI) values due to the outburst of CLCV, a study was carried out for tehsil Multan. Data was acquired for the months of June, July, August and September for the year 2010. Regression analysis between CLCV and meteorological conditions as well as between CLCV and NDVI was performed. Meteorological parameters included temperature, humidity, precipitation, cloud cover, wind direction, pan evaporation and sunshine hours. NDVI values were calculated from SPOT satellite imagery (1km) using ArcMap10 and WinDisp v5.1. Correlation coefficients obtained in most of the cases were acceptable however the significance F and P-value were higher than their critical value at 95% level of significance. Therefore significant correlation was found only between CLCV and temperature and between CLCV and PAN evaporation during the month of July.

Ahmed, A.; Akhtar, A.; Khalid, B.; Shamim, A.

2013-06-01

77

Functional Characterization of a Bidirectional Plant Promoter from Cotton Leaf Curl Burewala Virus Using an Agrobacterium-Mediated Transient Assay  

PubMed Central

The C1 promoter expressing the AC1 gene, and V1 promoter expressing the AV1 gene are located in opposite orientations in the large intergenic region of the Cotton leaf curl Burewala virus (CLCuBuV) genome. Agro-infiltration was used to transiently express putative promoter constructs in Nicotiana tabacum and Gossypium hirsutum leaves, which was monitored by a GUS reporter gene, and revealed that the bidirectional promoter of CLCuBuV transcriptionally regulates both the AC1 and AV1 genes. The CLCuBuV C1 gene promoter showed a strong, consistent transient expression of the reporter gene (GUS) in N. tabacum and G. hirsutum leaves and exhibited GUS activity two- to three-fold higher than the CaMV 35S promoter. The CLCuBuV bidirectional genepromoter is a nearly constitutive promoter that contains basic conserved elements. Many cis-regulatory elements (CREs) were also analyzed within the bidirectional plant promoters of CLCuBuV and closely related geminiviruses, which may be helpful in understanding the transcriptional regulation of both the virus and host plant. PMID:24424501

Ashraf, Muhammad Aleem; Shahid, Ahmad Ali; Rao, Abdul Qayyum; Bajwa, Kamran Shehzad; Husnain, Tayyab

2014-01-01

78

A Rapid and Efficient Method for Construction of an Infectious Clone of Tomato yellow leaf curl virus  

PubMed Central

Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is responsible for one of the most devastating viral diseases in tomato-growing countries and is becoming a serious problem in many subtropical and tropical countries. The climate in Korea is getting warmer and developing subtropical features in response to global warming. These changes are being accompanied by TYLCV, which is now becoming a large problem in the Korean tomato industry. The most effective way to reduce damage caused by TYLCV is to breed resistant varieties of tomatoes. To accomplish this, it is necessary to establish a simple inoculation technique for the efficient evaluation of resistance to TYLCV. Here, we present the rolling circle amplification (RCA) method, which employs a bacteriophage using phi-29 DNA polymerase for construction of infectious TYLCV clones. The RCA method is simple, does not require sequence information for cloning, and is less expensive and time consuming than conventional PCR based-methods. Furthermore, RCA-based construction of an infectious clone can be very useful to other emerging and unknown geminiviruses in Korea. PMID:25289018

Bang, Bongjun; Lee, Jongyun; Kim, Sunyoung; Park, Jungwook; Nguyen, Thao Thi; Seo, Young-Su

2014-01-01

79

A Rapid and Efficient Method for Construction of an Infectious Clone of Tomato yellow leaf curl virus.  

PubMed

Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is responsible for one of the most devastating viral diseases in tomato-growing countries and is becoming a serious problem in many subtropical and tropical countries. The climate in Korea is getting warmer and developing subtropical features in response to global warming. These changes are being accompanied by TYLCV, which is now becoming a large problem in the Korean tomato industry. The most effective way to reduce damage caused by TYLCV is to breed resistant varieties of tomatoes. To accomplish this, it is necessary to establish a simple inoculation technique for the efficient evaluation of resistance to TYLCV. Here, we present the rolling circle amplification (RCA) method, which employs a bacteriophage using phi-29 DNA polymerase for construction of infectious TYLCV clones. The RCA method is simple, does not require sequence information for cloning, and is less expensive and time consuming than conventional PCR based-methods. Furthermore, RCA-based construction of an infectious clone can be very useful to other emerging and unknown geminiviruses in Korea. PMID:25289018

Bang, Bongjun; Lee, Jongyun; Kim, Sunyoung; Park, Jungwook; Nguyen, Thao Thi; Seo, Young-Su

2014-09-01

80

Multiple Forms of Vector Manipulation by a Plant-Infecting Virus: Bemisia tabaci and Tomato Yellow Leaf Curl Virus  

PubMed Central

For many insect-vectored plant viruses, the relationship between feeding behavior and vector competence may prove integral to an understanding of the epidemiology of the resulting plant disease. While plant-infecting viruses are well known to change host plant physiology in a way that makes them more attractive to vectors, viral manipulation of the vectors themselves has only recently been reported. Previous research suggested that the rapid spread of Tomato yellow leaf curl virus (TYLCV) throughout China has been facilitated by its primary vector, the whitefly Bemisia tabaci. We conducted two experiments testing the impact of TYLCV infection of the host plant (tomato) and vector (B. tabaci biotypes B and Q) on whitefly feeding behavior. Whiteflies of biotypes B and Q both appeared to find TYLCV-infected plants more attractive, probing them more quickly and having a greater number of feeding bouts; this did not, however, alter the total time spent feeding. Viruliferous whiteflies fed more readily than uninfected whiteflies and spent more time salivating into sieve tube elements. Because vector salivation is essential for viral transmission, this virally mediated alteration of behavior should provide TYLCV a direct fitness benefit. This is the first report of such manipulation by a nonpropagative virus that belongs to an exclusively plant-infecting family of viruses (Geminiviridae). In the context of previous research showing that feeding on TYLCV-infected plants harms biotype B but helps biotype Q, the fact that both biotypes were equally affected by TYLCV also suggests that the virus may alter the biotype B-biotype Q competitive interaction in favor of biotype Q. PMID:23408638

Liu, Baiming; Preisser, Evan L.; Chu, Dong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun

2013-01-01

81

Regular or covert sex defines two lineages and worldwide superclones within the leaf-curl plum aphid (Brachycaudus helichrysi, Kaltenbach).  

PubMed

Asexual reproduction occurs widely in plants and animals, particularly in insects. Aphid species usually reproduce by cyclic parthenogenesis, but many species include obligate asexual lineages. We recently showed that the leaf-curl plum aphid, Brachycaudus helichrysi, actually encompasses two lineages, B. helichrysi H1 and H2. Ecological data suggest that these lineages have different life cycles. We conducted a large population genetics study, based on 14 microsatellite loci, to infer their respective life cycles and investigate their population structure and geographical distribution. Brachycaudus helichrysi H1 displayed the genetic signature of cyclical parthenogenesis, using plum trees as primary hosts for sexual reproduction, as classically described for B. helichrysi. This global survey showed that the Central Asian population of H1 was clearly differentiated from American-European populations. By contrast, B. helichrysi H2 displayed the typical signature of obligate asexual reproduction. H2 encompassed at least eight highly successful genotypes or superclones. This lack of ability to undergo sexual reproduction was confirmed for one of the superclones by sex induction experiments. We found only one B. helichrysi H2 population that underwent sexual reproduction, which was collected from peach trees, in Northern India. Our results confirm that H1 and H2 have different life cycles. Brachycaudus helichrysi H1 is clearly heteroecious using plum trees as primary hosts, while B. helichrysi H2 encompasses several anholocyclic lineages, and some heteroecious populations that until now have only been found associated with peach trees as primary hosts. We discuss implications of these findings for the pest status of B. helichrysi lineages. PMID:23786407

Piffaretti, J; Clamens, A-L; Vanlerberghe-Masutti, F; Gupta, R K; Call, E; Halbert, S; Jousselin, E

2013-08-01

82

Only minimal regions of tomato yellow leaf curl virus (TYLCV) are required for replication, expression and movement.  

PubMed

The IL-60 platform, consisting of a disarmed form of tomato yellow leaf curl virus (TYLCV) and auxiliary components, was previously developed as a nontransgenic universal vector system for gene expression and silencing that can express an entire operon in plants. IL-60 does not allow rolling-circle replication; hence, production of viral single-stranded (ss) DNA progeny is prevented. We used this double-stranded (ds) DNA-restricted platform (uncoupled from the dsDNA?ssDNA replication phase of progeny viral DNA) for functional genomics studies of TYLCV. We report that the noncoding 314-bp intergenic region (IR) is the only viral element required for viral dsDNA replication. None of the viral genes are required, suggesting recruitment of host factors that recognize the IR. We further show that IR-carrying reporter genes are also capable of replication but remain confined to the cells into which they were introduced. Only two sense-oriented viral genes (V1 and V2) need to be added to the IR-carrying construct for expression and movement. Hence, any IR-dsDNA construct supplemented with V1 and V2 becomes a replication-competent, mobile and expressing plant plasmid. All viral functions (replication, expression and movement) are determined by the IR and the sense-oriented genes. The complementary-oriented viral genes have auxiliary roles in the late phase of the virus "life cycle". The previously reported involvement of some viral genes in expression and movement is therefore revised. PMID:24719195

Gover, Ofer; Peretz, Yuval; Mozes-Koch, Rita; Maori, Eyal; Rabinowitch, Haim D; Sela, Ilan

2014-09-01

83

Molecular characterization and infectivity of a Tomato leaf curl New Delhi virus variant associated with newly emerging yellow mosaic disease of eggplant in India  

PubMed Central

Background Begomoviruses have emerged as serious problem for vegetable and fiber crops in the recent past, frequently in tropical and subtropical region of the world. The association of begomovirus with eggplant yellow mosaic disease is hitherto unknown apart from one report from Thailand. A survey in Nagpur, Central India, in 2009-2010 showed severe incidence of eggplant yellow mosaic disease. Here, we have identified and characterized a begomovirus responsible for the newly emerging yellow mosaic disease of eggplant in India. Results The complete DNA-A and DNA-B genomic components of the causative virus were cloned and sequenced. Nucleotide sequence analysis of DNA-A showed that it shared highest 97.6% identity with Tomato leaf curl New Delhi virus-India[India:Udaipur:Okra:2007] and lowest 87.9% identity with Tomato leaf curl New Delhi virus-India[India:NewDelhi:Papaya:2005], while DNA-B showed highest 94.1% identity with ToLCNDV-IN[IN:UD:Ok:07] and lowest 76.2% identity with ToLCNDV-India[India:Lucknow]. Thus, it appears that this begomovirus is a variant of ubiquitous ToLCNDV and hence, we suggest the name ToLCNDV-India[India:Nagpur:Eggplant:2009] for this variant. The pathogenicity of ToLCNDV-IN[IN:Nag:Egg:09] isolate was confirmed by agroinfiltraion and dimeric clones of DNA-A and DNA-B induced characteristic yellow mosaic symptoms in eggplants and leaf curling in tomato plants. Conclusion This is the first report of a ToLCNDV variant moving to a new agriculturally important host, eggplant and causing yellow mosaic disease. This is also a first experimental demonstration of Koch's postulate for a begomovirus associated with eggplant yellow mosaic disease. PMID:21676270

2011-01-01

84

Implication of the Bacterial Endosymbiont Rickettsia spp. in Interactions of the Whitefly Bemisia tabaci with Tomato yellow leaf curl virus  

PubMed Central

ABSTRACT Numerous animal and plant viruses are transmitted by arthropod vectors in a persistent, circulative manner. Tomato yellow leaf curl virus (TYLCV) is transmitted by the sweet potato whitefly Bemisia tabaci. We report here that infection with Rickettsia spp., a facultative endosymbiont of whiteflies, altered TYLCV-B. tabaci interactions. A B. tabaci strain infected with Rickettsia acquired more TYLCV from infected plants, retained the virus longer, and exhibited nearly double the transmission efficiency compared to an uninfected B. tabaci strain with the same genetic background. Temporal and spatial antagonistic relationships were discovered between Rickettsia and TYLCV within the whitefly. In different time course experiments, the levels of virus and Rickettsia within the insect were inversely correlated. Fluorescence in situ hybridization analysis of Rickettsia-infected midguts provided evidence for niche exclusion between Rickettsia and TYLCV. In particular, high levels of the bacterium in the midgut resulted in higher virus concentrations in the filter chamber, a favored site for virus translocation along the transmission pathway, whereas low levels of Rickettsia in the midgut resulted in an even distribution of the virus. Taken together, these results indicate that Rickettsia, by infecting the midgut, increases TYLCV transmission efficacy, adding further insights into the complex association between persistent plant viruses, their insect vectors, and microorganism tenants that reside within these insects. IMPORTANCE Interest in bacterial endosymbionts in arthropods and many aspects of their host biology in agricultural and human health systems has been increasing. A recent and relevant studied example is the influence of Wolbachia on dengue virus transmission by mosquitoes. In parallel with our recently studied whitefly-Rickettsia-TYLCV system, other studies have shown that dengue virus levels in the mosquito vector are inversely correlated with bacterial load. Our work here presents evidence of unifying principles between vectors of plant and animal viruses in a role for endosymbionts in manipulating vector biology and pathogen transmission. Our results demonstrate the influence of an interesting and prominent bacterial endosymbiont in Bemisia tabaci in TYLCV transmission, a worldwide disease infecting tomatoes. Besides its agricultural importance, this system provides interesting insights into Bemisia interaction with these newly discovered endosymbionts. PMID:24600010

Kliot, Adi; Cilia, Michelle; Czosnek, Henryk

2014-01-01

85

Molecular detection and partial characterization of a begomovirus causing leaf curl disease of potato in sub-Himalayan West Bengal, India.  

PubMed

The characteristic disease symptoms of apical leaf curl, crinkled leaves and conspicuous mosaic were observed in potato plants grown in areas of Coochbehar, one of the distinct agroclimatic zones of sub-Himalayan West Bengal. Whitefly (Bemisia tabaci) population was also observed in and around the infected plants. The characteristic disease symptoms and presence of whitefly (Bemisia tabaci) population indicated the possibility of begomovirus infection. Total DNA was extracted from infected samples and PCR was carried out using begomovirus specific primers. PCR product of 1539 nucleotide long containing pre-coat protein, coat protein, AC5, AC3, AC2 and partial AC1 gene of DNA-Asegment and 1001 nucleotide long DNA-B containing BV1 and BC1 genes were submitted to the GenBank (accession numbers HQ597033 for DNA-A and JN390432 for DNA-B). The amplified DNA-A and DNA-B segment showed highest 98% and 99% nucleotide sequence similarity respectively with Tomato leaf curl New Delhi virus (ToLCNDV). In phylogenetic analysis also the virus sequence clustered with ToLCNDV isolates. The disease was successfully transmitted to healthy tomato plants using both whitefly vector, B. tabaci and mechanical sap inoculation using sap of infected potato leaves. It is the first record of begomovirus infection of cultivated potato in sub-Himalayan West Bengal of Eastern India. PMID:24813019

Saha, Aniruddha; Saha, Bikram; Saha, Dipanwita

2014-05-01

86

Effects of genetic changes to the begomovirus/betasatellite complex causing cotton leaf curl disease in South Asia post-resistance breaking.  

PubMed

Cotton leaf curl disease (CLCuD) has been a problem for cotton production across Pakistan and north-eastern India since the early 1990s. The appearance of the disease has been attributed to the introduction, and near monoculture of highly susceptible cotton varieties. During the intervening period the genetic make-up of the virus(es) causing the disease has changed dramatically. The most prominent of these changes has been in response to the introduction of CLCuD-resistant cotton varieties in the late 1990s, which provided a brief respite from the losses due to the disease. During the 1990s the disease was shown to be caused by multiple begomoviruses and a single, disease-specific betasatellite. Post-resistance breaking the complex encompassed only a single begomovirus, Cotton leaf curl Burewala virus (CLCuBuV), and a recombinant version of the betasatellite. Surprisingly CLCuBuV lacks an intact transcriptional-activator protein (TrAP) gene. The TrAP gene is found in all begomoviruses and encodes a product of ?134 amino acids that is important in virus-host interactions; being a suppressor of post-transcriptional gene silencing (host defence) and a transcription factor that modulates host gene expression, including microRNA genes. Recent studies have highlighted the differences between CLCuBuV and the earlier viruses that are part of on-going efforts to define the molecular basis for resistance breaking in cotton. PMID:24361351

Briddon, Rob W; Akbar, Fazal; Iqbal, Zafar; Amrao, Luqman; Amin, Imran; Saeed, Muhammad; Mansoor, Shahid

2014-06-24

87

Comparative Transcriptome Profiling of a Resistant vs. Susceptible Tomato (Solanum lycopersicum) Cultivar in Response to Infection by Tomato Yellow Leaf Curl Virus  

PubMed Central

Tomato yellow leaf curl virus (TYLCV) threatens tomato production worldwide by causing leaf yellowing, leaf curling, plant stunting and flower abscission. The current understanding of the host plant defense response to this virus is very limited. Using whole transcriptome sequencing, we analyzed the differential gene expression in response to TYLCV infection in the TYLCV-resistant tomato breeding line CLN2777A (R) and TYLCV-susceptible tomato breeding line TMXA48-4-0 (S). The mixed inoculated samples from 3, 5 and 7 day post inoculation (dpi) were compared to non-inoculated samples at 0 dpi. Of the total of 34831 mapped transcripts, 209 and 809 genes were differentially expressed in the R and S tomato line, respectively. The proportion of up-regulated differentially expressed genes (DEGs) in the R tomato line (58.37%) was higher than that in the S line (9.17%). Gene ontology (GO) analyses revealed that similar GO terms existed in both DEGs of R and S lines; however, some sets of defense related genes and their expression levels were not similar between the two tomato lines. Genes encoding for WRKY transcriptional factors, R genes, protein kinases and receptor (-like) kinases which were identified as down-regulated DEGs in the S line were up-regulated or not differentially expressed in the R line. The up-regulated DEGs in the R tomato line revealed the defense response of tomato to TYLCV infection was characterized by the induction and regulation of a series of genes involved in cell wall reorganization, transcriptional regulation, defense response, ubiquitination, metabolite synthesis and so on. The present study provides insights into various reactions underlining the successful establishment of resistance to TYLCV in the R tomato line, and helps in the identification of important defense-related genes in tomato for TYLCV disease management. PMID:24260487

Chen, Tianzi; Lv, Yuanda; Zhao, Tongming; Li, Nan; Yang, Yuwen; Yu, Wengui; He, Xin; Liu, Tingli; Zhang, Baolong

2013-01-01

88

Characterization of a New World Monopartite Begomovirus Causing Leaf Curl Disease of Tomato in Ecuador and Peru Reveals a New Direction in Geminivirus Evolution  

PubMed Central

All characterized whitefly-transmitted geminiviruses (begomoviruses) with origins in the New World (NW) have bipartite genomes composed of a DNA-A and DNA-B component. Recently, an NW begomovirus lacking a DNA-B component was associated with tomato leaf curl disease (ToLCD) in Peru, and it was named Tomato leaf deformation virus (ToLDeV). Here, we show that isolates of ToLDeV associated with ToLCD in Ecuador and Peru have a single, genetically diverse genomic DNA that is most closely related to DNA-A components of NW bipartite begomoviruses. Agroinoculation of multimeric clones of the genomic DNA of three ToLDeV genotypes (two variants and a strain) resulted in the development of tomato leaf curl symptoms indistinguishable from those of ToLCD in Ecuador and Peru. Biological properties of these ToLDeV genotypes were similar to those of Old World (OW) monopartite tomato-infecting begomoviruses, including lack of sap transmissibility, phloem limitation, a resistance phenotype in tomato germplasm with the Ty-1 gene, and functional properties of the V1 (capsid protein) and C4 genes. Differences in symptom phenotypes induced by the ToLDeV genotypes in tomato and Nicotiana benthamiana plants were associated with a highly divergent left intergenic region and C4 gene. Together, these results establish that ToLDeV is an emergent NW monopartite begomovirus that is causing ToLCD in Ecuador and Peru. This is the first report of an indigenous NW monopartite begomovirus, and evidence is presented that it emerged from the DNA-A component of a NW bipartite progenitor via convergent evolution and recombination. PMID:23468482

Melgarejo, Tomas A.; Kon, Tatsuya; Rojas, Maria R.; Paz-Carrasco, Lenin; Zerbini, F. Murilo

2013-01-01

89

Real-time PCR protocols for the quantification of the begomovirus tomato yellow leaf curl Sardinia virus in tomato plants and in its insect vector.  

PubMed

Tomato yellow leaf curl Sardinia virus (TYLCSV) (Geminiviridae) is an important pathogen, transmitted by the whitefly Bemisia tabaci, that severely affects the tomato production in the Mediterranean basin. Here, we describe real-time PCR protocols suitable for relative and absolute quantification of TYLCSV in tomato plants and in whitefly extracts. Using primers and probe specifically designed for TYLCSV, the protocols for relative quantification allow to compare the amount of TYLCSV present in different plant or whitefly samples, normalized to the amount of DNA present in each sample using endogenous tomato or Bemisia genes as internal references. The absolute quantification protocol allows to calculate the number of genomic units of TYLCSV over the genomic units of the plant host (tomato), with a sensitivity of as few as ten viral genome copies per sample. The described protocols are potentially suitable for several applications, such as plant breeding for resistance, analysis of virus replication, and virus-vector interaction studies. PMID:25287496

Noris, Emanuela; Miozzi, Laura

2015-01-01

90

Water Balance, Hormone Homeostasis, and Sugar Signaling Are All Involved in Tomato Resistance to Tomato Yellow Leaf Curl Virus1[C][W][OPEN  

PubMed Central

Vacuolar water movement is largely controlled by membrane channels called tonoplast-intrinsic aquaporins (TIP-AQPs). Some TIP-AQP genes, such as TIP2;2 and TIP1;1, are up-regulated upon exposure to biotic stress. Moreover, TIP1;1 transcript levels are higher in leaves of a tomato (Solanum lycopersicum) line resistant to Tomato yellow leaf curl virus (TYLCV) than in those of a susceptible line with a similar genetic background. Virus-induced silencing of TIP1;1 in the tomato resistant line and the use of an Arabidopsis (Arabidopsis thaliana) tip1;1 null mutant showed that resistance to TYLCV is severely compromised in the absence of TIP1:1. Constitutive expression of tomato TIP2;2 in transgenic TYLCV-susceptible tomato and Arabidopsis plants was correlated with increased TYLCV resistance, increased transpiration, decreased abscisic acid levels, and increased salicylic acid levels at the early stages of infection. We propose that TIP-AQPs affect the induction of leaf abscisic acid, which leads to increased levels of transpiration and gas exchange, as well as better salicylic acid signaling. PMID:24989233

Sade, Dagan; Sade, Nir; Shriki, Oz; Lerner, Stephen; Gebremedhin, Alem; Karavani, Asaf; Brotman, Yariv; Osorio, Sonia; Fernie, Alisdair R.; Willmitzer, Lothar; Czosnek, Henryk; Moshelion, Menachem

2014-01-01

91

Recruitment of the Host Plant Heat Shock Protein 70 by Tomato Yellow Leaf Curl Virus Coat Protein Is Required for Virus Infection  

PubMed Central

A functional capsid protein (CP) is essential for host plant infection and insect transmission of Tomato yellow leaf curl virus (TYLCV) and other monopartite begomoviruses. We have previously shown that TYLCV CP specifically interacts with the heat shock protein 70 (HSP70) of the virus insect vector, Bemisia tabaci. Here we demonstrate that during the development of tomato plant infection with TYLCV, a significant amount of HSP70 shifts from a soluble form into insoluble aggregates. CP and HSP70 co-localize in these aggregates, first in the cytoplasm, then in the nucleus of cells associated with the vascular system. CP-HSP70 interaction was demonstrated by co-immunopreciptation in cytoplasmic - but not in nuclear extracts from leaf and stem. Inhibition of HSP70 expression by quercetin caused a decrease in the amount of nuclear CP aggregates and a re-localization of a GFP-CP fusion protein from the nucleus to the cytoplasm. HSP70 inactivation resulted in a decrease of TYLCV DNA levels, demonstrating the role of HSP70 in TYLCV multiplication in planta. The current study reveals for the first time the involvement of plant HSP70 in TYLCV CP intracellular movement. As described earlier, nuclear aggregates contained TYLCV DNA-CP complexes and infectious virions. Showing that HSP70 localizes in these large nuclear aggregates infers that these structures operate as nuclear virus factories. PMID:23894631

Gorovits, Rena; Moshe, Adi; Ghanim, Murad; Czosnek, Henryk

2013-01-01

92

Making a friend from a foe: expressing a GroEL gene from the whitefly Bemisia tabaci in the phloem of tomato plants confers resistance to tomato yellow leaf curl virus  

Microsoft Academic Search

Summary  Some (perhaps all) plant viruses transmitted in a circulative manner by their insect vectors avoid destruction in the haemolymph\\u000a by interacting with GroEL homologues, ensuring transmission. We have previously shown that the phloem-limited begomovirus\\u000a tomato yellow leaf curl virus (TYLCV) interacts in vivo and in vitro with GroEL produced by the whitefly vector Bemisia tabaci. In this study, we have

F. Akad; A. Eybishtz; D. Edelbaum; R. Gorovits; O. Dar-Issa; N. Iraki; H. Czosnek

2007-01-01

93

Whitefly population dynamics and evaluation of whitefly-transmitted tomato yellow leaf curl virus (TYLCV)-resistant tomato genotypes as whitefly and TYLCV reservoirs.  

PubMed

Sweetpotato whitefly, Bemisia tabaci (Gennadius), and whitefly-transmitted tomato yellow leaf curl virus (TYLCV) are major threats to tomato production in the southeastern United States. TYLCV was introduced to Florida from the Caribbean islands and has spread to other southern states of the United States. In Georgia, in recent years, the incidence of TYLCV has been steadily increasing. Studies were conducted to monitor population dynamics of whiteflies in the vegetable production belt of Georgia, to evaluate TYLCV-resistant genotypes against whiteflies and TYLCV, and to assess the potential role of resistant genotypes in TYLCV epidemiology. Monitoring studies indicated that the peak incidence of whiteflies varied seasonally from year to year. In general, whitefly populations were not uniformly distributed. Tomato genotypes exhibited minor differences in their ability to support whitefly populations. TYLCV symptoms were visually undetectable in all but one resistant genotype. The infection rates (visually) in susceptible genotypes ranged from 40 to 87%. Greenhouse inoculations with viruliferous whiteflies followed by polymerase chain reaction (PCR) indicated that up to 100% of plants of resistant genotypes were infected, although predominantly symptomless. TYLCV acquisition by whiteflies from TYLCV-infected genotypes was tested by PCR; TYLCV acquisition rates from resistant genotypes were less than from susceptible genotypes. Nevertheless, this difference did not influence TYLCV transmission rates from resistant to susceptible genotypes. Results emphasize that resistant genotypes can serve as TYLCV and whitefly reservoirs and potentially influence TYLCV epidemics. PMID:22928328

Srinivasan, Rajagopalbabu; Riley, David; Diffie, Stan; Sparks, Alton; Adkins, Scott

2012-08-01

94

Functional Characterization of Coat Protein and V2 Involved in Cell to Cell Movement of Cotton Leaf Curl Kokhran Virus-Dabawali  

PubMed Central

The functional attributes of coat protein (CP) and V2 of the monopartite begomovirus, Cotton leaf curl Kokhran virus- Dabawali were analyzed in vitro and in vivo by their overexpression in E coli, insect cells and transient expression in the plant system. Purified recombinant V2 and CP proteins were shown to interact with each other using ELISA and surface plasmon resonance. Confocal microscopy of Sf21 cells expressing V2 and CP proteins revealed that V2 localized to the cell periphery and CP to the nucleus. Deletion of the N terminal nuclear localization signal of CP restricted its distribution to the cytoplasm. GFP-V2 and YFP-CP transiently expressed in N.benthamiana plants by agroinfiltration substantiated the localization of V2 to the cell periphery and CP predominantly to the nucleus. Interestingly, upon coinfiltration, CP was found both in the nucleus and in the cytoplasm along with V2. These results suggest that the interaction of V2 and CP may have important implications in the cell to cell movement. PMID:22110597

Poornima Priyadarshini, C. G.; Ambika, M. V.; Tippeswamy, R.; Savithri, H. S.

2011-01-01

95

Sweet pepper confirmed as a reservoir host for tomato yellow leaf curl virus by both agro-inoculation and whitefly-mediated inoculation.  

PubMed

Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, has a single-stranded DNA genome. TYLCV can induce severe disease symptoms on tomato plants, but other hosts plants such as cucurbits and peppers are asymptomatic. A full-length DNA clone of a Korean TYLCV isolate was constructed by rolling-circle amplification from TYLCV-infected tomatoes in Korea. To assess relative susceptibility of sweet pepper varieties to TYLCV, 19 cultivars were inoculated with cloned TYLCV by agro-inoculation. All TYLCV-infected sweet peppers were asymptomatic, even though Southern hybridization and polymerase chain reaction analysis showed TYLCV genomic DNA accumulation in roots, stems, and newly produced shoots. Southern hybridization indicated that TYLCV replicated and moved systemically from agro-inoculated apical shoot tips to roots or newly produced shoots of sweet peppers. Whitefly-mediated inoculation experiments showed that TYLCV can be transmitted to tomatoes from TYLCV-infected sweet peppers. Taken together, these results indicate that sweet pepper can be a reservoir for TYLCV in nature. PMID:24777825

Kil, Eui-Joon; Byun, Hee-Seong; Kim, Sunhoo; Kim, Jaedeok; Park, Jungan; Cho, Seungchan; Yang, Dong-Cheol; Lee, Kyeong-Yeoll; Choi, Hong-Soo; Kim, Ji-Kwang; Lee, Sukchan

2014-09-01

96

Peptide aptamers that bind to geminivirus replication proteins confer a resistance phenotype to tomato yellow leaf curl virus and tomato mottle virus infection in tomato.  

PubMed

Geminiviruses constitute a large family of single-stranded DNA viruses that cause serious losses in important crops worldwide. They often exist in disease complexes and have high recombination and mutation rates, allowing them to adapt rapidly to new hosts and environments. Thus, an effective resistance strategy must be general in character and able to target multiple viruses. The geminivirus replication protein (Rep) is a good target for broad-based disease control because it is highly conserved and required for viral replication. In an earlier study, we identified a set of peptide aptamers that bind to Rep and reduce viral replication in cultured plant cells. In this study, we selected 16 of the peptide aptamers for further analysis in yeast two-hybrid assays. The results of these experiments showed that all 16 peptide aptamers interact with all or most of the Rep proteins from nine viruses representing the three major Geminiviridae genera and identified two peptide aptamers (A22 and A64) that interact strongly with different regions in the Rep N terminus. Transgenic tomato lines expressing A22 or A64 and inoculated with Tomato yellow leaf curl virus or Tomato mottle virus exhibited delayed viral DNA accumulation and often contained lower levels of viral DNA. Strikingly, the effect on symptoms was stronger, with many of the plants showing no symptoms or strongly attenuated symptoms. Together, these results established the efficacy of using Rep-binding peptide aptamers to develop crops that are resistant to diverse geminiviruses. PMID:23824791

Reyes, Maria Ines; Nash, Tara E; Dallas, Mary M; Ascencio-Ibáñez, J Trinidad; Hanley-Bowdoin, Linda

2013-09-01

97

Rapid spread of a recently introduced virus (tomato yellow leaf curl virus) and its vector Bemisia tabaci (Hemiptera: Aleyrodidae) in Liaoning Province, China.  

PubMed

In Liaoning Province, China, tomato yellow leaf curl virus (TYLCV) was first detected in 2009 and in only four counties. To quantify the spread of TYLCV and to identify potential factors influencing its spread in Liaoning Province, we assayed for TYLCV within 1,055 whiteflies (Bemisia tabaci (Gennadius) complex) from 74 populations and 29 counties in 2011. The B. tabaci species of these individuals was determined based on molecular markers. TYLCV was found in 13 counties (Donggang, Liaoyang, Kazuo, Lingyuan, Heishan, Liaozhong, Kaiyuan, Taian, Dawa, Dashiqiao, Beizhen, Linghai, and Xingcheng) and was most frequently detected in the central plain. In addition, the percentage of whiteflies with TYLCV was significantly higher in B. tabaci Q than in B. tabaci B but was unrelated to the hosts (pepper, eggplant, tomato, cucumber, and kidney bean) on which the whiteflies had been collected. These results demonstrate that TYLCV has spread rapidly in Liaoning Province since its first detection and suggest that its spread is more closely associated with the introduction of B. tabaci Q than with the species of host plant. These findings also indicate that controls are now needed to reduce the further spread of TYLCV and that these controls should include the management of B. tabaci Q populations. PMID:24665690

Zhang, Wan-Min; Fu, Hai-Bin; Wang, Wen-Hang; Piao, Chun-Shu; Tao, Yun-Li; Guo, Dong; Chu, Dong

2014-02-01

98

Amino Acids in the Capsid Protein of Tomato Yellow Leaf Curl Virus That Are Crucial for Systemic Infection, Particle Formation, and Insect Transmission  

PubMed Central

A functional capsid protein (CP) is essential for host plant infection and insect transmission in monopartite geminiviruses. We studied two defective genomic DNAs of tomato yellow leaf curl virus (TYLCV), Sic and SicRcv. Sic, cloned from a field-infected tomato, was not infectious, whereas SicRcv, which spontaneously originated from Sic, was infectious but not whitefly transmissible. A single amino acid change in the CP was found to be responsible for restoring infectivity. When the amino acid sequences of the CPs of Sic and SicRcv were compared with that of a closely related wild-type virus (TYLCV-Sar), differences were found in the following positions: 129 (P in Sic and SicRcv, Q in Sar), 134 (Q in Sic and Sar, H in SicRcv) and 152 (E in Sic and SicRcv, D in Sar). We constructed TYLCV-Sar variants containing the eight possible amino acid combinations in those three positions and tested them for infectivity and transmissibility. QQD, QQE, QHD, and QHE had a wild-type phenotype, whereas PHD and PHE were infectious but nontransmissible. PQD and PQE mutants were not infectious; however, they replicated and accumulated CP, but not virions, in Nicotiana benthamiana leaf discs. The Q129P replacement is a nonconservative change, which may drastically alter the secondary structure of the CP and affect its ability to form the capsid. The additional Q134H change, however, appeared to compensate for the structural modification. Sequence comparisons among whitefly-transmitted geminiviruses in terms of the CP region studied showed that combinations other than QQD are present in several cases, but never with a P129. PMID:9811744

Noris, E.; Vaira, A. M.; Caciagli, P.; Masenga, V.; Gronenborn, B.; Accotto, G. P.

1998-01-01

99

The sex pheromones of mealy plum (Hyalopterus pruni) and leaf-curl plum (Brachycaudus helichrysi) aphids: identification and field trapping of male and gynoparous aphids in prune orchards.  

PubMed

Mealy plum, Hyalopterus pruni, and leaf-curl plum, Brachycaudus helichrysi, aphids are the primary arthropod pests in orchards that produce dried plums (i.e., prunes). The sexual stage of their respective lifecycles occurs on prune trees in the fall, during which time males respond to sex pheromones produced by oviparous females. Air-entrainment collections confirmed that oviparous H. pruni and B. helichrysi emitted combinations of (4aS, 7S, 7aR)-nepetalactone and (1R, 4aS, 7S, 7aR)-nepetalactol. The responses of H. pruni and B. helichrysi to these compounds in ratios of 1:0, 0:1, 1:1, 2.6:1, 3.4:1, 5:1, 7:1, and 0:0 (no-pheromone control) using water traps were determined in field experiments conducted in prune orchards during the fall. The greatest number of male H. pruni was caught in traps releasing a 1:1 ratio of (4aS, 7S, 7aR)-nepetalactone and (1R, 4aS, 7S, 7aR)-nepetalactol, while male B. helichrysi were caught in similar numbers in traps releasing any of the two-component ratios tested. There was no evidence that any of the pheromone treatments influenced trap catches of gynoparae of either species. Results suggest that addition of sex pheromone lures increases trap catches of male H. pruni and B. helichrysi, and that this approach may improve monitoring and management of these pests in prune orchards. Knowledge gained from this study contributes to the understanding of the ecology of insect pests in prune orchards. PMID:22549554

Symmes, Emily J; Dewhirst, Sarah Y; Birkett, Michael A; Campbell, Colin A M; Chamberlain, Keith; Pickett, John A; Zalom, Frank G

2012-05-01

100

Lemony Summer Squash Ingredients  

E-print Network

teaspoon dried rosemary, crumbled 2 tablespoons fresh lemon juice (1 lemon) Directions 1. Wash squash tender (about 4 minutes). 5. After squash is tender, cut lemon in half and squeeze juice from both sides

Liskiewicz, Maciej

101

A developmentally regulated lipocalin-like gene is overexpressed in Tomato yellow leaf curl virus-resistant tomato plants upon virus inoculation, and its silencing abolishes resistance.  

PubMed

To discover genes involved in tomato resistance to Tomato yellow leaf curl virus (TYLCV), we previously compared cDNA libraries from susceptible (S) and resistant (R) tomato lines. Among the genes preferentially expressed in R plants and upregulated by TYLCV infection was a gene encoding a lipocalin-like protein. This gene was termed Solanum lycopersicum virus resistant/susceptible lipocalin (SlVRSLip). The SlVRSLip structural gene sequence of R and S plants was identical. SlVRSLip was expressed in leaves during a 15-day window starting about 40 days after sowing (20 days after planting). SlVRSLip was upregulated by Bemisia tabaci (the TYLCV vector) feeding on R plant leaves, and even more strongly upregulated following whitefly-mediated TYLCV inoculation. Silencing of SlVRSLip in R plants led to the collapse of resistance upon TYLCV inoculation and to a necrotic response along the stem and petioles accompanied by ROS production. Contrary to previously identified tomato lipocalin gene DQ222981, SlVRSLip was not regulated by cold, nor was it regulated by heat or salt. The expression of SlVRSLip was inhibited in R plants in which the hexose transporter gene LeHT1 was silenced. In contrast, the expression of LeHT1 was not inhibited in SlVRSLip-silenced R plants. Hence, in the hierarchy of the gene network conferring TYLCV resistance, SlVRSLip is downstream of LeHT1. Silencing of another gene involved in resistance, a Permease-I like protein, did not affect the expression of SlVRSLip and LeHT1; expression of the Permease was not affected by silencing SlVRSLip or LeHT1, suggesting that it does not belong to the same network. The triple co-silencing of SlVRSLip, LeHT1 and Permease provoked an immediate cessation of growth of R plants upon infection and the accumulation of large amounts of virus. SlVRSLip is the first lipocalin-like gene shown to be involved in resistance to a plant virus. PMID:22843056

Sade, Dagan; Eybishtz, Assaf; Gorovits, Rena; Sobol, Iris; Czosnek, Henryk

2012-10-01

102

Wheat curl mite resistance: interactions of mite feeding with wheat streak mosaic virus infection.  

PubMed

The majority of plant viruses are dependent on arthropod vectors for spread between plants. Wheat streak mosaic virus (family Potyviridae, genus Tritimovirus, WSMV) is transmitted by the wheat curl mite, Aceria tosichella Keifer, and this virus and vector cause extensive yield losses in most major wheat (Triticum aestivum L.)-growing regions of the world. Many cultivars in use are susceptible to this vector-virus complex, and yield losses of 10-99% have been documented. wheat curl mite resistance genes have been identified in goat grass, Aegilops tauschii (Coss) Schmal., and transferred to hexaploid wheat, but very few varieties contain effectively wheat curl mite resistance, due to virulent wheat curl mite populations. However, wheat curl mite resistance remains an effective strategy to reduce losses due to WSMV. The goal of our project was to identify the most effective, reproducible, and rapid method for assessing wheat curl mite resistance. We also wanted to determine whether mite resistance is affected by WSMV infection, because the pathogen and pest commonly occur together. Single and group wheat curl mite infestations produced similar amounts of leaf rolling and folding on wheat curl mite-susceptible wheat varieties that were independent of initial wheat curl mite infestation. This finding will allow accurate, efficient, large-scale screening of wheat germplasm for wheat curl mite resistance by infesting plants with sections of wheat leaf tissue containing mixed stages of wheat curl mite. The wheat curl mite-resistant breeding line 'OK05312' displayed antibiosis (reduced wheat curl mite population development). The effect of WSMV infection on wheat curl mite reproduction was genotype-dependent. Mite populations increased on infected wheat curl mite- and WSMV-susceptible plants compared with uninfected plants, but WSMV infection had no significant effect on wheat curl mite populations on resistant plants. OK05312 is a strong source of wheat curl mite resistance for wheat breeding programs. PMID:21882710

Murugan, M; Sotelo Cardona, P; Duraimurugan, P; Whitfield, A E; Schneweis, D; Starkey, S; Smith, C M

2011-08-01

103

FOOD PRESERVATION SERIES Summer Squash  

E-print Network

in the refrigerator, away from raw meat so that meat juices do not contaminate it. Wash hands before and after because the skin is thin and fragile. Store summer squash in the refrigerator. Wash squash and trim ends. Remove from boiling water and cool. Put cooled squash into freezer bags, leav-ing

104

Curls of My Dreams.  

ERIC Educational Resources Information Center

Describes an art activity in which students draw ribbons (thin watercolor paper that, when torn, will stand up in a curling fashion). Explains in detail the assignment in which students used pencil rendering or charcoal pencil depending on the type of paper used for the assignment. (CMK)

Greenman, Geri

2001-01-01

105

Diverse Rock Named Squash  

NASA Technical Reports Server (NTRS)

This image from the Sojourner rover's right front camera was taken on Sol 27. The Pathfinder lander is seen at middle left. The large rock at right, nicknamed 'Squash', exhibits a diversity of textures. It looks very similar to a conglomerate, a type of rock found on Earth that forms from sedimentary processes.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and managed the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

1997-01-01

106

Squash and Stretch  

NSDL National Science Digital Library

This online activity has you order multiple images of a bouncing ball to show how, in animation, an object appears to lengthen as it falls, flatten as it hits the ground, and lengthen as it bounces up. This technique is used to produce the exaggerated look of an animated cartoon, but follows the rules of physics in that the object elongates along its axis of acceleration (stretch) and contracts when it meets resistance (squash). If images are out of place, they can be moved, rather than starting all over.

OMSI

2005-01-01

107

Summer Squash with Garlic Ingredients  

E-print Network

cloves on a cutting board, and lay flat part of knife on top. Use heel of hand and slap knife to break to skillet. 5. Add tarragon. Cook until squash are tender, about 8 minutes. Equipment: Cutting board Knife

Liskiewicz, Maciej

108

Squash(ed): Craniofacial and vertebral injury from collision on squash court  

PubMed Central

Squash is a popular racquet sport not usually associated with severe head or spinal injury. The incidence of squash-related injury ranges from 35.5 to 80.9 per 100,000 players, with the most common sites being the lower-limbs and eyes. We present a case of extensive traumatic craniomaxillofacial and vertebral injury resulting from collision on a squash court, without use of protective gear. The patient sustained fractures of the frontal bone, orbits, maxillae, zygomas, the first and second cervical vertebrae and the spinous process of the seventh cervical vertrebra. This is the first case of squash-related injury with such extensive craniofacial and vertebral involvement. This unique case required multiple surgical procedures as well as an extensive admission to the intensive care unit and highlights the risk of significant craniomaxillofacial trauma in sports not usually associated with such injuries. PMID:23248511

Atik, Alp; Krilis, Matthew; Parker, Geoffrey

2012-01-01

109

Squash(ed): Craniofacial and vertebral injury from collision on squash court.  

PubMed

Squash is a popular racquet sport not usually associated with severe head or spinal injury. The incidence of squash-related injury ranges from 35.5 to 80.9 per 100,000 players, with the most common sites being the lower-limbs and eyes. We present a case of extensive traumatic craniomaxillofacial and vertebral injury resulting from collision on a squash court, without use of protective gear. The patient sustained fractures of the frontal bone, orbits, maxillae, zygomas, the first and second cervical vertebrae and the spinous process of the seventh cervical vertrebra. This is the first case of squash-related injury with such extensive craniofacial and vertebral involvement. This unique case required multiple surgical procedures as well as an extensive admission to the intensive care unit and highlights the risk of significant craniomaxillofacial trauma in sports not usually associated with such injuries. PMID:23248511

Atik, Alp; Krilis, Matthew; Parker, Geoffrey

2012-10-01

110

Conductance Oscillations in Squashed Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

A combination of molecular dynamics and electrical conductance calculations are used to probe the electromechanical properties of squashed metallic carbon nanotubes. We find that the conductance and bandgap of armchair nanotubes show oscillations upon squashing. The physical origin of these oscillations is attributed to interaction of carbon atoms with a fourth neighbor. Squashing of armchair and zigzag nanotubes ultimately leads to metallic behavior.

Mehrez, H.; Anantram, M. P.; Svizhenko, A.

2003-01-01

111

Squashed black holes in Goedel universes  

SciTech Connect

We investigate five-dimensional rotating and charged black holes with squashed horizons in Goedel universes. The general solution was recently derived by applying a squashing transformation on the general nonextremal charged and rotating black hole in the Goedel universe found by Wu. We give a discussion of the squashed geometry and also consider its lift to ten dimensions and discuss the T-dual geometry. Finally, using the counterterms method we compute its conserved charges and explore its thermodynamics.

Stelea, Cristian; Schleich, Kristin; Witt, Donald [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada)

2008-12-15

112

Influence of Water Relations and Temperature on Leaf Movements of Rhododendron Species 1  

PubMed Central

Rhododendron maximum L. and R. Catawbiense L. are subcanopy evergreen shrubs of the eastern United States deciduous forest. Field measurements of climate factors and leaf movements of these species indicated a high correlation between leaf temperature and leaf curling; and between leaf water potential and leaf angle. Laboratory experiments were performed to isolate the influence of temperature and cellular water relations on leaf movements. Significant differences were found between the patterns of temperature induction of leaf curling in the two species. Leaves of the species which curled at higher temperatures (R. catawbiense) also froze at higher leaf temperatures. However, in both cases leaf curling occurred at leaf temperatures two to three degrees above the leaf freezing point. Pressure volume curves indicated that cellular turgor loss was associated with a maximum of 45% curling while 100% or more curling occurred in field leaves which still had positive cell turgor. Moisture release curves indicated that 70% curling requires a loss of greater than 60% of symplastic water which corresponds to leaf water potentials far below those experienced in field situations. Conversely, most laboratory induced changes in leaf angle could be related to leaf cell turgor loss. PMID:16665296

Nilsen, Erik Tallak

1987-01-01

113

Impact of Curing Methods on Curling of Concrete Pavements  

E-print Network

Impact of Curing Methods on Curling of Concrete Pavements Amir Hajibabaee Travis Ebisch Tyler Ley is Curling? Curling is when the edges of a concrete pavement (or slab) deflect up compared to the middle. Warping is the same thing only the edges deflect downward. curling warping #12;Why do pavements curl

114

A Squashed Heliosphere - Duration: 1:28.  

NASA Video Gallery

Heliophysics' finding of the 'squashed' heliosphere when Voyager 1 and 2 crossed the bubble of solar wind at different distances from the sun. This led to a change in the way we see the shape of ou...

115

Squash vein yellowing virus, a novel ipomovirus, isolated from squash and watermelon in Florida  

Technology Transfer Automated Retrieval System (TEKTRAN)

A novel whitefly-transmitted member of the family Potyviridae was isolated from a squash plant (Cucurbita pepo) with vein yellowing symptoms in Florida. The virus, for which the name Squash vein yellowing virus (SqVYV) is proposed, has flexuous rod-shaped particles of ~840 nm in length. SqVYV was ...

116

Influence of velocity curl on conservation laws  

E-print Network

The paper discusses impact of the velocity curl on some conservation laws in the gravitational field and electromagnetic field, by means of the characteristics of quaternions. When the velocity curl can not be neglected, it will cause the predictions to departure slightly from the conservation laws, which include mass continuity equation, charge continuity equation, and conservation of spin, etc. And the scalar potential of gravitational field has an effect on the speed of light, the conservation of mass, and conservation of charge, etc. The results explain how the velocity curl influences some conservation laws in the gravitational field and electromagnetic field.

Zihua Weng

2008-10-01

117

Complete Genome Sequence of a Novel Genotype of Squash Mosaic Virus Infecting Squash in Spain  

PubMed Central

The complete genome sequence of a new isolate of squash mosaic virus (SqMV) infecting squash plants in Spain was obtained using deep sequencing of small RNAs. The low nucleotide sequence identities, with only 87 to 88% for RNA1 and 84 to 86% for RNA2 to known SqMV isolates, suggested that this isolate belongs to a novel genotype. PMID:25676773

Li, Rugang; Gao, Shan; Berendsen, Sven; Fei, Zhangjun

2015-01-01

118

Scythe (pelargonic acid) weed control in squash  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season-long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and y...

119

Analysis of band-gap formation in squashed armchair CNTs  

NASA Astrophysics Data System (ADS)

The electronic properties of squashed arm-chair CNTs are modeled using constraint free density functional tight binding molecular dynamics simulations. Independent from CNT diameter, squashing path can be divided into three regimes. In the first regime, the CNT deforms with negligible force. In the second one, there is significantly more resistance to squashing with the force being ˜40-100 nN/per CNT unit cell. In the last regime, the CNT looses its hexagonal structure resulting in force drop-off followed by substantial force enhancement upon squashing. We compute the change in band-gap (Eg) as a function of squashing and our main results are: (i) Eg initially opens due to interaction between atoms at the top and bottom sides of CNT. The ?-orbital approximation is successful in modeling the Eg opening at this stage. (ii) In the second regime of squashing, large ?-? interaction at the edges becomes important, which can lead to Eg oscillation. (iii) Contrary to a common perception, nanotubes with broken mirror symmetry can have zero Eg. (iv) All armchair nanotubes become metallic in the third regime of squashing.[Phys. Rev. B 71, 155421 (2005)

Mehrez, H.; Svizhenko, A.; Anantram, M. P.; Elstner, M.; Frauenheim, T.

2006-03-01

120

Computed tomography of ball pythons (Python regius) in curled recumbency.  

PubMed

Anesthesia and tube restraint methods are often required for computed tomography (CT) of snakes due to their natural tendency to curl up. However, these restraint methods may cause animal stress. The aim of this study was to determine whether the CT appearance of the lungs differs for ball pythons in a curled position vs. tube restraint. Whole body CT was performed on ten clinically healthy ball pythons, first in curled and then in straight positions restrained in a tube. Curved multiplanar reformatted (MPR) lung images from curled position scans were compared with standard MPR lung images from straight position scans. Lung attenuation and thickness were measured at three locations for each scan. Time for positioning and scanning was 12 ± 5 min shorter for curled snakes compared to tube restraint. Lung parenchyma thickness and attenuation declined from cranial to caudal on both straight and curled position images. Mean lung parenchyma thickness was greater in curled images at locations 1 (P = 0.048) and 3 (P = 0.044). Mean lung parenchyma thickness decreased between location 1 and 2 by 86-87% (straight: curled) and between location 1 and 3 by 51-50% (straight: curled). Mean lung attenuation at location 1 was significantly greater on curled position images than tube restraint images (P = 0.043). Findings indicated that CT evaluation of the lungs is feasible for ball pythons positioned in curled recumbency if curved MPR is available. However, lung parenchyma thickness and attenuation in some locations may vary from those acquired using tube restraint. PMID:24438485

Hedley, Joanna; Eatwell, Kevin; Schwarz, Tobias

2014-01-01

121

Sequential applications of pelargonic acid for weed control in squash  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weed control can be a constant challenge, especially when dealing with the limited herbicide options available to organic vegetable producers. Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide weed control throughout the production season. Although...

122

Curling of thin tubes: Analytical and experimental study  

NASA Astrophysics Data System (ADS)

The curling of thin tubes under compressive loads produces double walled tubes for many engineering applications. Experiments have been performed on annealed copper, low carbon steel, stainless steel, and aluminum tubes to determine the relationship between the curling process parameters and the tube geometry, as well as tube material properties. Effects of friction and work hardening during forming are included in the analysis. The analytical and experimental results are compared with published results to determine the validity of the proposed analytical model. The model can be used to determine the curling load and the correct die radius for successful curling. For simple and quick determination of the die radius, the present work introduces design curves, which correlate the tube geometry with the radius of the forming die.

El-Domiaty, A.

1997-08-01

123

Cucumber (Cucumis sativus L.) and kabocha squash (Cucurbita moschata Duch).  

PubMed

We established improved methods for Agrobacterium-mediated transformation of cucumber (Cucumis sativus L.) and kabocha squash (Cucurbita moschata Duch). Vacuum infiltration of cotyledonary explants with Agrobacterium suspension enhanced the Agrobacterium infection efficiency in the proximal regions of explants. Wounding treatment was also essential for kabocha squash. Cocultivation on filter paper wicks suppressed necrosis of explants, keeping regeneration efficacy. Putative transgenic plants were screened by kanamycin resistance and green fluorescent protein (GFP) fluorescence. These putative transgenic plants grew normally and T1 seeds were obtained, and stable integration and transmission of the transgene in T1 generations were confirmed by Southern hybridization and PCR. The average transgenic efficiency for cucumber and kabocha squash was 11.9?±?3.5 and 9.2?±?2.9 %, respectively. PMID:25300850

Nanasato, Yoshihiko; Tabei, Yutaka

2015-01-01

124

The Sports Science of Curling: A Practical Review  

PubMed Central

Curling is a sport played on ice in which two teams each deliver 8 granite stones towards a target, or ‘house’. It is the only sport in which the trajectory of the projectile can be influenced after it has been released by the athlete. This is achieved by sweeping the ice in front of the stone to change the stone-ice friction and thereby enable to stone to travel further, curl more or stay straight. Hard sweeping is physically demanding. Different techniques of sweeping can also have different effects on the stone. This paper will review the current research behind sweeping a curling stone, outline the physiological demands of sweeping, the associated performance effects and suggest potential strategies of sweeping that can be used by both coaches and curling teams. Key points Sweeping a curling stone can be highly physically demanding. Effective sweeping requires a combination of downward force and brush head speed, determined by the stone velocity. Sweeping on the left or right of a stone can help the stone to remain straight or curl more depending on the rotation of the stone. This can lead to the development of sweeping and playing tactics and contribute to team selection. PMID:24149588

Bradley, John L.

2009-01-01

125

Enhanced photoresponse in curled graphene ribbons.  

PubMed

Graphene has become one of the most promising materials for future optoelectronics due to its ultrahigh charge-carrier mobility, high light transmission, and universal absorbance in the near-infrared and visible spectral ranges. However, a zero band gap and ultrafast recombination of the photoexcited electron-hole pairs limit graphene's potential in photovoltaic generation. Recent studies have shown that hot carriers can enhance photovoltaic generation in graphene p-n junctions through the photothermoelectric effect (PTE). It is, therefore, desirable to synthesize graphene nanostructures with an intrinsic PTE-induced photocurrent response. Here we report a simple method to synthesize quasi-one dimensional (quasi-1D) curled graphene ribbons (CGRs) that generate a photocurrent response with two orders of magnitude enhancement. Scanning photocurrent and photoluminescence measurements reveal that the photocurrent response is primarily attributed to the PTE and that the infrared emission may arise from thermal radiation. These results offer a new way to fabricate graphene-based optoelectronics with an enhanced photoresponse. PMID:24131998

Jarrahi, Zeynab; Cao, Yunhao; Hong, Tu; Puzyrev, Yevgeniy S; Wang, Bin; Lin, Junhao; Huffstutter, Alex H; Pantelides, Sokrates T; Xu, Ya-Qiong

2013-12-21

126

Characteristics of whitefly transmission of Squash vein yellowing virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV), a recently described ipomovirus, is transmitted by the whitefly, Bemisia tabaci Gennadius, B strain. Understanding the characteristics of transmission is essential for developing management strategies for this virus, which is the causal agent for watermelon vine ...

127

Squash bug: Vector of cucurbit yellow vine disease pathogen  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cucurbits, especially watermelon and cantaloupe, are important crops in the South Central region of the U.S. and are affected by a variety of insect and disease complexes. Prominent among these are the squash bug, Anasa tristis (DeGeer) and a destructive vine decline, cucurbit yellow vine disease (...

128

Post-directed application of pelargonic acid for squash  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide post-emergent weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and...

129

Squash vein yellowing virus and its effects on watermelon  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV), a novel whitefly-transmitted member of the Potyviridae was recently shown to cause a watermelon vine decline in Florida. Watermelon plants were grown under whitefly-free conditions in a greenhouse and inoculated with buffer (mock), SqVYV, or SqVYV and Papaya rin...

130

Constraining cosmic string parameters with curl mode of CMB lensing  

NASA Astrophysics Data System (ADS)

We present constraints on a cosmic string network with a measurement of weak gravitational lensing from CMB temperature map. The cosmic string network between the observer and last scattering surface of CMB photons generates vector and/or tensor metric perturbations, and the deflection of CMB photons by these gravitational fields has a curl mode which is not produced by the scalar metric perturbations. In this paper, we use the power spectrum of curl mode obtained from Planck to constrain the string tension, G?, and the reconnection probability, P. In demonstrating the parameter constraints with Planck curl mode, we also measure the lensing power spectrum from the Atacama Cosmology Telescope (ACT) 2008 season data, which have better angular resolution with lower instrumental noise on a much smaller chunk of the sky. Assuming P=1, the upper bound on tension is G?=6.6×10-5 with 2? (95% C.L.), using curl mode from Planck, which is weaker than that from the small-scale temperature power spectrum. For small values of P, however, the constraint from curl mode becomes tighter compared to that from the temperature power spectrum. For P?10-2, we obtain the constraint on the combination of the string parameters as G?P-1?3.4×10-5 at more than 2? (95% C.L.).

Namikawa, Toshiya; Yamauchi, Daisuke; Taruya, Atsushi

2013-10-01

131

Evolution of perturbations of squashed Kaluza-Klein black holes: Escape from instability  

SciTech Connect

The squashed Kaluza-Klien (KK) black holes differ from the Schwarzschild black holes with asymptotic flatness or the black strings even at energies for which the KK modes are not excited yet, so that squashed KK black holes open a window in higher dimensions. Another important feature is that the squashed KK black holes are apparently stable and, thereby, let us avoid the Gregory-Laflamme instability. In the present paper, the evolution of scalar and gravitational perturbations in time and frequency domains is considered for these squashed KK black holes. The scalar field perturbations are analyzed for general rotating squashed KK black holes. Gravitational perturbations for the so-called zero mode are shown to be decayed for nonrotating black holes, in concordance with the stability of the squashed KK black holes. The correlation of quasinormal frequencies with the size of extra dimension is discussed.

Ishihara, Hideki; Kimura, Masashi; Konoplya, Roman A.; Murata, Keiju; Soda, Jiro; Zhidenko, Alexander [Department of Mathematics and Physics, Graduate School of Science, Osaka City University, Osaka 558-8585 (Japan); Department of Physics, Kyoto University, Kyoto 606-8501 (Japan); Department of Physics, Kyoto University, Kyoto 606-8501 (Japan) Kavli Institute for Theoretical Physics, Zhong Guan Cun East Street 55, Beijing 100080 (China); Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo-SP (Brazil)

2008-04-15

132

DIVERGENCE-FREE AND CURL-FREE WAVELETS ON THE SQUARE FOR NUMERICAL SIMULATIONS  

E-print Network

DIVERGENCE-FREE AND CURL-FREE WAVELETS ON THE SQUARE FOR NUMERICAL SIMULATIONS SOULEYMANE KADRI Grenoble cedex 9, France August 30, 2011 Abstract We present a construction of divergence-free and curl-free and integration. We introduce new BMRAs and wavelets for the spaces of divergence-free and curl-free vector

Boyer, Edmond

133

Covolume solutions of three dimensional div-curl equations  

NASA Technical Reports Server (NTRS)

Delaunay-Voronoi mesh systems provide a generalization of the classical rectangular staggered meshes to unstructured meshes. It is shown how such 'covolume' discretizations may be applied to div-curl systems in three dimensions. Error estimates are proved and confirmed by a numerical illustration.

Nicolaides, R. A.; Wu, X.

1995-01-01

134

Methyl bromide alternatives in a bell pepper–squash rotation  

Microsoft Academic Search

Field studies were conducted to evaluate potential methyl bromide alternatives against multiple pests in a bell pepper (Capsicum annum L.) – squash (Cucurbita pepo L.) cropping sequence. Early in the growing season, the most effective treatments in suppressing purple nutsedge (Cyperus rotundus L.) emergence through the polyethylene mulch were methyl bromide, methyl iodide, and chisel-injected 1,3-dichloropropene plus chloropicrin [1,3-D+C35 (chisel)].

T. M. Webster; A. S. Csinos; A. W. Johnson; C. C. Dowler; D. R. Sumner; R. L. Fery

2001-01-01

135

A Rotating Kaluza-Klein Black Hole with Squashed Horizons  

E-print Network

We find a rotating Kaluza-Klein black hole solution with a squashed $S^3$ horizon in five dimensions. This is a Kerr counterpart of the charged one found by Ishihara and Matsuno (hep-th/0510094) recently. The space-time is geodesic complete and free of naked singularity. Its asymptotic structure is a twisted $S^1$ fiber bundle over a four dimensional Minkowski space-time. We also study the mass and thermodynamics of this black hole.

Tower Wang

2006-09-05

136

Local and Systemic Changes in Squash Gene Expression in Response to Silverleaf Whitefly Feeding  

PubMed Central

Squash genes (SLW1 and SLW3) induced systemically after silverleaf whitefly feeding were identified. Differences in the local and systemic expression of SLW1 and SLW3 after feeding by the closely related silverleaf and sweetpotato whiteflies were observed. Temporal and spatial studies showed that SLW1 and SLW3 were induced when second, third, and fourth nymphal instars were feeding. Although only barely detected after wounding and bacterial infection, SLW1 and SLW3 RNAs were abundant during water-deficit stress. Treatments with wound/defense signal molecules showed that SLW1 RNAs accumulated in response to methyl jasmonate and ethylene, whereas SLW3 was not regulated by known wound/defense signals, suggesting utilization of a novel mechanism for defense signal transduction. SLW1 RNAs accumulated during floral and fruit development, whereas SLW3 RNAs were not detected during vegetative or reproductive development. The potential roles of SLW1, an M20b peptidase–like protein, and SLW3, a ?-glucosidase–like protein, in defense and the leaf-silvering disorder are discussed. PMID:10948259

van de Ven, Wilhelmina T. G.; LeVesque, Cynthia S.; Perring, Thomas M.; Walling, Linda L.

2000-01-01

137

Development of Mass Rearing Methods, and Novel Methods For Control of the Squash Bug, Anasa Tristis (De Geer) (Heteroptera: Coreidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Squash bug, Anasa tristis (De Geer), a major pest of squash, pumpkin, watermelon, cucumber and cantaloupe, uses piercing-sucking mouthparts to imbibe plant fluids. The severity of plant damage resulting from squash bug feeding causes extensive damage to stems resulting in wilting, fruit discolo...

138

Overwintering squash bugs harbor and transmit the causal agent of cucurbit yellow vine disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Since 1988, cucurbit crops, particularly watermelon, cantaloupe, and squash, grown in Oklahoma and Texas have experienced devastating losses from cucurbit yellow vine disease (CYVD), caused by the phloem-limited bacterium, Serratia marcescens. Squash bug [Anasa tristis (DeGeer)] is a putative vecto...

139

SQUASH BEETLE ON CUCURBITS Frankie Lam, Ricky E. Foster, Extension Entomologists,  

E-print Network

SQUASH BEETLE ON CUCURBITS Frankie Lam, Ricky E. Foster, Extension Entomologists, Dan Egel to the family of lady beetles (Coccinellidae). Most insects in this family are beneficial, often eating large numbers of pest insects such as aphids. The exceptions are the squash beetle and the Mexican bean beetle

Ginzel, Matthew

140

Potential organic herbicides for squash production: Pelargonic acid herbicides AXXE® and Scythe®  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season-long weed control. Although corn gluten meal has shown promise as an early-season pre-emergent organic herbicide in squash production, any uncontrolled weeds can inflict serious yield reducti...

141

STRUCTURAL AND PHYSICOCHEMICAL CHARACTERISTICS OF WINTER SQUASH (CUCURBITA MAXIMA D.) FRUIT STARCHES AT HARVEST  

Technology Transfer Automated Retrieval System (TEKTRAN)

Structures and physicochemical properties of starch isolated from fruit (pepo) of seven winter squash cultivars (Cucurbita maxima D.) were studied. Squash starches exhibited the B-type X-ray diffraction pattern and had most granules with diameters of 1.5-2.5 micrometers, 6-8 micrometers, and 11-13 ...

142

Universal squash model for optical communications using linear optics and threshold detectors  

SciTech Connect

Transmission of photons through open-air or optical fibers is an important primitive in quantum-information processing. Theoretical descriptions of this process often consider single photons as information carriers and thus fail to accurately describe experimental implementations where any number of photons may enter a detector. It has been a great challenge to bridge this big gap between theory and experiments. One powerful method for achieving this goal is by conceptually squashing the received multiphoton states to single-photon states. However, until now, only a few protocols admit a squash model; furthermore, a recently proven no-go theorem appears to rule out the existence of a universal squash model. Here we show that a necessary condition presumed by all existing squash models is in fact too stringent. By relaxing this condition, we find that, rather surprisingly, a universal squash model actually exists for many protocols, including quantum key distribution, quantum state tomography, Bell's inequality testing, and entanglement verification.

Fung, Chi-Hang Fred; Chau, H. F. [Department of Physics and Center of Computational and Theoretical Physics, University of Hong Kong, Pokfulam Road (Hong Kong); Lo, Hoi-Kwong [Center for Quantum Information and Quantum Control, Department of Physics and Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4 (Canada)

2011-08-15

143

Curling and rolling dynamics of naturally curved ribbons.  

PubMed

When a straight rod is bent and suddenly released on one end, a burst of dispersive flexural waves propagates down the material as predicted by linear beam theories. However, we show that for ribbons with a longitudinal natural radius of curvature a0, geometrical constraints lead to strain localization which controls the dynamics. This localized region of deformation selects a specific curling deformation front which travels down the ribbon when initially flattened and released. Performing experiments on different ribbons, in air and in water, we show that initially, on length scales on the order of a0, the curling front moves as a power law of time with an exponent ranging from 0.5 to 2 for increasing values of the ribbons' width. At longer time scales, the material wraps itself at a constant speed Vr into a roll of radius R ? a0. The relationship between Vr and R is calculated by a balance between kinetic, elastic and gravitational energy and both internal and external powers dissipated. When gravity and drag are negligible, we observe that a0/R reaches a limiting value of 0.48 that we predict by solving the Elastica on the curled ribbon considering the centrifugal forces due to rotation. The solution we propose represents a solitary traveling curvature wave which is reminiscent to propagating instabilities in mechanics. PMID:24695463

Arriagada, Octavio Albarrán; Massiera, Gladys; Abkarian, Manouk

2014-05-01

144

Hydro-Responsive Curling of the Resurrection Plant Selaginella lepidophylla.  

PubMed

The spirally arranged stems of the spikemoss Selaginella lepidophylla, an ancient resurrection plant, compactly curl into a nest-ball shape upon dehydration. Due to its spiral phyllotaxy, older outer stems on the plant interlace and envelope the younger inner stems forming the plant centre. Stem curling is a morphological mechanism that limits photoinhibitory and thermal damages the plant might experience in arid environments. Here, we investigate the distinct conformational changes of outer and inner stems of S. lepidophylla triggered by dehydration. Outer stems bend into circular rings in a relatively short period of desiccation, whereas inner stems curl slowly into spirals due to hydro-actuated strain gradient along their length. This arrangement eases both the tight packing of the plant during desiccation and its fast opening upon rehydration. The insights gained from this work shed light on the hydro-responsive movements in plants and might contribute to the development of deployable structures with remarkable shape transformations in response to environmental stimuli. PMID:25623361

Rafsanjani, Ahmad; Brulé, Véronique; Western, Tamara L; Pasini, Damiano

2015-01-01

145

Hydro-Responsive Curling of the Resurrection Plant Selaginella lepidophylla  

PubMed Central

The spirally arranged stems of the spikemoss Selaginella lepidophylla, an ancient resurrection plant, compactly curl into a nest-ball shape upon dehydration. Due to its spiral phyllotaxy, older outer stems on the plant interlace and envelope the younger inner stems forming the plant centre. Stem curling is a morphological mechanism that limits photoinhibitory and thermal damages the plant might experience in arid environments. Here, we investigate the distinct conformational changes of outer and inner stems of S. lepidophylla triggered by dehydration. Outer stems bend into circular rings in a relatively short period of desiccation, whereas inner stems curl slowly into spirals due to hydro-actuated strain gradient along their length. This arrangement eases both the tight packing of the plant during desiccation and its fast opening upon rehydration. The insights gained from this work shed light on the hydro-responsive movements in plants and might contribute to the development of deployable structures with remarkable shape transformations in response to environmental stimuli. PMID:25623361

Rafsanjani, Ahmad; Brulé, Véronique; Western, Tamara L.; Pasini, Damiano

2015-01-01

146

Leaf Shape  

NSDL National Science Digital Library

This illustrated guide is designed to help students recognize and learn the different types of leaf shapes. The single Web page, which can be easily printed for use at field sites, shows five leaf shapes.

147

Leaf Margins  

NSDL National Science Digital Library

This illustrated guide is designed to help students recognize and learn the difference between entire and toothed leaf margins. The single Web page can be easily printed for use at field sites. Both leaf margin illustrations identify the leaf blade and the petiole.

148

Physiological profiles and sport specific fitness of Asian elite squash players.  

PubMed Central

There is a scarcity of descriptive data on the physiological characteristics of elite Asian squash players. The purpose of this study was to evaluate the physiological profile and sports specific fitness of Hong Kong elite squash players. It was conducted before the selection of the Hong Kong national squash team for the 1992 Asian Squash Championship. Ten elite squash players were selected as subjects for the study. Maximum oxygen uptake was measured using a continuous treadmill running test. A sports specific field test was performed in a squash court. The following means (s.d.) were observed: height 172.6(4.3) cm; weight 67.7(6.9) kg; body fat 7.4(3.4)%; forced vital capacity (FVC) 5.13(0.26) litres; maximum oxygen uptake (VO2max) 61.7(3.4) ml.kg-1.min-1; anaerobic threshold (AT) 80.2(3.3)% of VO2max; alactic power index 15.5(1.8) W.kg-1; lactic work index 323.5(29.4) J.kg-1, peak isokinetic dominant knee extensor and flexor strengths 3.11(0.29) Nm.kg-1 and 1.87(0.18) Nm.kg-1. The results show that the Hong Kong squash players have relatively high cardiorespiratory sports specific fitness and muscle strength which may be one of the key factors that contributed to the success of the Hong Kong team in the Asian Championship. PMID:8800847

Chin, M K; Steininger, K; So, R C; Clark, C R; Wong, A S

1995-01-01

149

Origin of fine-scale wind stress curl structures in the Benguela and Canary upwelling systems  

NASA Astrophysics Data System (ADS)

studies have shown the primary importance of wind stress curl in coastal upwelling dynamics. The main goal of this new analysis is to describe the QuikSCAT surface wind stress curl at various scales in the Benguela and Canary upwelling systems. The dominant spatial pattern is characterized by cyclonic curl near continental boundaries and anticyclonic curl offshore, in association with equatorward alongshore (upwelling favorable) wind stress. At a smaller scale, we demonstrate the sensitivity of the QuikSCAT wind stress curl to coastal processes related to sea surface temperature (SST) mesoscale fluctuations by presenting a linear relationship between the curl and crosswind SST gradients. Despite the spatial and temporal sensitivity of the underlying thermal coupling coefficient, a local analysis of the fraction of the curl ascribed to SST variability shows that SST is a main driver of the wind stress curl variability and magnitude over the upwelling extension zone (˜100-300 km from the coast) in both the Canary and Benguela systems. Closer to the shore, the curl patterns derived from QuikSCAT observations are only loosely related to SST-wind interactions. As a working hypothesis, they can also be associated with the coastline geometry and orographic effects that are likely to play an important role in local cooling processes.

Desbiolles, F.; Blanke, B.; Bentamy, A.; Grima, N.

2014-11-01

150

Curled encodes the Drosophila homolog of the vertebrate circadian deadenylase Nocturnin.  

PubMed

Drosophila melanogaster curled, one of the first fly mutants described by T. H. Morgan >90 years ago, is the founding member of a series of curled wing phenotype mutants widely used as markers in fruit fly genetics. The expressivity of the wing phenotype is environmentally modulated, suggesting that the mutation affects the metabolic status of cells rather than a developmental control gene. However, the molecular identity of any of the curled wing marker mutant genes is still unknown. In a screen for starvation-responsive genes, we previously identified the single fly homolog of the vertebrate nocturnin genes, which encode cytoplasmic deadenylases that act in the post-transcriptional control of genes by poly(A) tail removal of target mRNAs prior to their degradation. Here we show that curled encodes Drosophila Nocturnin and that the gene is required at pupal stage for proper wing morphogenesis after eclosion of the fly. Despite the complex ontogenetic expression pattern of the gene, curled is not expressed in the developing wing, and wing-specific curled knockdown mediated by RNAi does not result in the curled wing phenotype, indicating a tissue-nonautonomous, systemic mode of curled gene function. Our study not only presents an entry point into the functional analysis of invertebrate nocturnins but also paves the way for the identification of the still elusive Nocturnin target mRNAs by genetic suppressor screens on the curled wing phenotype. PMID:19581445

Grönke, Sebastian; Bickmeyer, Iris; Wunderlich, Roman; Jäckle, Herbert; Kühnlein, Ronald P

2009-09-01

151

Ingot butt curl control of aluminum ingots through the use of shim material  

SciTech Connect

Ravenswood Aluminum Corporation (RAC) has experienced a reduction in butt curl by as much as three inches through the use of shim tape. A factor that affects butt curl is how the shim material is applied. For example, the amount of butt curl is significantly less if shim tape is applied to all four faces of the molds as compared to only two faces of the mold. This paper will compare the amount of butt curl versus (1) different types of shim material and (2) application (four faces versus two faces) of the shim material.

Whiteleather, B.S. [Ravenswood Aluminum Corp., WV (United States)

1996-10-01

152

Strong gravitational lensing in a rotating Kaluza-Klein black hole with squashed horizons  

E-print Network

We have investigated the strong gravitational lensing in a rotating squashed Kaluza-Klein (KK) black hole spacetime. Our result show that the strong gravitational lensings in the rotating squashed KK black hole spacetime have some distinct behaviors from those in the backgrounds of the four-dimensional Kerr black hole and of the squashed KK G\\"{o}del black hole. In the rotating squashed KK black hole spacetime, the marginally circular photon radius $\\rho_{ps}$, the coefficient $\\bar{a}$, $\\bar{b}$, the deflection angle $\\alpha(\\theta)$ in the $\\phi$ direction and the corresponding observational variables are independent of whether the photon goes with or against the rotation of the background, which is different with those in the usual four-dimensional Kerr black hole spacetime. Moreover, we also find that with the increase of the scale of extra dimension $\\rho_0$, the marginally circular photon radius $\\rho_{ps}$ and the angular position of the relativistic images $\\theta_\\infty$ first decreases and then increases in the rotating squashed KK black hole for fixed rotation parameter $b$, but in the squashed KK G\\"{o}del black hole they increase for the smaller global rotation parameter $j$ and decrease for the larger one. In the extremely squashed case $\\rho_0=0$, the coefficient $\\bar{a}$ in the rotating squashed KK black hole increases monotonously with the rotation parameter, but in the squashed KK G\\"{o}del black hole it is a constant and independent of the global rotation of the G\\"{o}del Universe.

LiYong Ji; Songbai Chen; Jiliang Jing

2014-02-26

153

Strong gravitational lensing in a rotating Kaluza-Klein black hole with squashed horizons  

NASA Astrophysics Data System (ADS)

We have investigated the strong gravitational lensing in a rotating squashed Kaluza-Klein (KK) black hole spacetime. Our result show that the strong gravitational lensings in the rotating squashed KK black hole spacetime have some distinct behaviors from those in the backgrounds of the four-dimensional Kerr black hole and of the squashed KK Gödel black hole. In the rotating squashed KK black hole spacetime, the marginally circular photon radius ? ps , the coefficient , , the deflection angle ?( ?) in the ? direction and the corresponding observational variables are independent of whether the photon goes with or against the rotation of the background, which is different with those in the usual four-dimensional Kerr black hole spacetime. Moreover, we also find that with the increase of the scale of extra dimension ?0, the marginally circular photon radius ? ps and the angular position of the relativistic images ? ? first decreases and then increases in the rotating squashed KK black hole for fixed rotation parameter b, but in the squashed KK Gödel black hole they increase for the smaller global rotation parameter j and decrease for the larger one. In the extremely squashed case ? 0 = 0, the coefficient a in the rotating squashed KK black hole increases monotonously with the rotation parameter, but in the squashed KK Gödel black hole it is a constant and independent of the global rotation of the Gödel Universe. These information could help us to understand further the effects of the rotation parameter and the scale of extra dimension on the strong gravitational lensing in the black hole spacetimes.

Ji, Liyong; Chen, Songbai; Jing, Jiliang

2014-03-01

154

Occurrence of Squash yellow mild mottle virus and Pepper golden mosaic virus in Potential New Hosts in Costa Rica.  

PubMed

Leaf samples of Solanum lycopersicum, Capsicum annuum, Cucurbita moschata, Cucurbita pepo, Sechium edule and Erythrina spp. were collected. All samples were positive for begomoviruses using polymerase chain reaction and degenerate primers. A sequence of ?1,100 bp was obtained from the genomic component DNA-A of 14 samples. In addition, one sequence of ?580 bp corresponding to the coat protein (AV1) was obtained from a chayote (S. edule) leaf sample. The presence of Squash yellow mild mottle virus (SYMMoV) and Pepper golden mosaic virus (PepGMV) were confirmed. The host range reported for SYMMoV includes species of the Cucurbitaceae, Caricaceae and Fabaceae families. This report extends the host range of SYMMoV to include the Solanaceae family, and extends the host range of PepGMV to include C. moschata, C. pepo and the Fabaceae Erythrina spp. This is the first report of a begomovirus (PepGMV) infecting chayote in the Western Hemisphere. PMID:25288955

Castro, Ruth M; Moreira, Lisela; Rojas, María R; Gilbertson, Robert L; Hernández, Eduardo; Mora, Floribeth; Ramírez, Pilar

2013-09-01

155

Occurrence of Squash yellow mild mottle virus and Pepper golden mosaic virus in Potential New Hosts in Costa Rica  

PubMed Central

Leaf samples of Solanum lycopersicum, Capsicum annuum, Cucurbita moschata, Cucurbita pepo, Sechium edule and Erythrina spp. were collected. All samples were positive for begomoviruses using polymerase chain reaction and degenerate primers. A sequence of ?1,100 bp was obtained from the genomic component DNA-A of 14 samples. In addition, one sequence of ?580 bp corresponding to the coat protein (AV1) was obtained from a chayote (S. edule) leaf sample. The presence of Squash yellow mild mottle virus (SYMMoV) and Pepper golden mosaic virus (PepGMV) were confirmed. The host range reported for SYMMoV includes species of the Cucurbitaceae, Caricaceae and Fabaceae families. This report extends the host range of SYMMoV to include the Solanaceae family, and extends the host range of PepGMV to include C. moschata, C. pepo and the Fabaceae Erythrina spp. This is the first report of a begomovirus (PepGMV) infecting chayote in the Western Hemisphere. PMID:25288955

Castro, Ruth M.; Moreira, Lisela; Rojas, María R.; Gilbertson, Robert L.; Hernández, Eduardo; Mora, Floribeth; Ramírez, Pilar

2013-01-01

156

Curricular Resource Library (cURL): Earth and Environmental Sciences  

NSDL National Science Digital Library

The cURL Earth and Environmental Sciences collection provides access to educational materials emphasizing the origin, evolution, and current state of the Earth. The collection is targeted toward undergraduate students and offers access to information about solid-earth geological processes, surficial processes, geochemistry, ecology, and aquatic sciences. By studying the approximately 4.5 billion-year history of our planet, including development of our atmosphere, water bodies, mountains, and natural resources, one learns more about the current functioning of the planet and possible environmental implications of human interferences with the natural system.

2004-08-20

157

Effect of the shoulder position on the biceps brachii emg in different dumbbell curls  

PubMed Central

Incline Dumbbell Curl (IDC) and Dumbbell Preacher Curl (DPC) are two variations of the standard Dumbbell Biceps Curl (DBC), generally applied to optimize biceps brachii contribution for elbow flexion by fixing shoulder at a specific angle. The aim of this study is to identify changes in the neuromuscular activity of biceps brachii long head for IDC, DPC and DBC exercises, by taking into account the changes in load moment arm and muscle length elicited by each dumbbell curl protocol. A single cycle (concentric-eccentric) of DBC, IDC and DPC, was applied to 22 subjects using a submaximal load of 40% estimated from an isometric MVC test. The neuromuscular activity of biceps brachii long head was compared by further partitioning each contraction into three phases, according to individual elbow joint range of motion. Although all protocols elicited a considerable level of activation of the biceps brachii muscle (at least 50% of maximum RMS), the contribution of this muscle for elbow flexion/extension varied among exercises. The submaximal elbow flexion (concentric) elicited neuro muscular activity up to 95% of the maximum RMS value during the final phase of IDC and DBC and 80% for DPC at the beginning of the movement. All exercises showed significant less muscle activity for the elbow extension (eccentric). The Incline Dumbbell Curl and the classical Dumbbell Biceps Curl resulted in similar patterns of biceps brachii activation for the whole range of motion, whereas Dumbbell Preacher Curl elicited high muscle activation only for a short range of elbow joint angle. Key pointsThe Incline Dumbbell Curl and the Dumbbell Biceps Curl resulted in a considerable neuromuscular effort throughout the whole elbow range of motion.The Incline Dumbbell Curl and the Dumbbell Biceps Curl may be preferable for the improvement of biceps brachii force in training programs. PMID:24150552

Oliveira, Liliam F.; Matta, Thiago T.; Alves, Daniel S.; Garcia, Marco A.C.; Vieira, Taian M.M.

2009-01-01

158

Effect of the shoulder position on the biceps brachii emg in different dumbbell curls.  

PubMed

Incline Dumbbell Curl (IDC) and Dumbbell Preacher Curl (DPC) are two variations of the standard Dumbbell Biceps Curl (DBC), generally applied to optimize biceps brachii contribution for elbow flexion by fixing shoulder at a specific angle. The aim of this study is to identify changes in the neuromuscular activity of biceps brachii long head for IDC, DPC and DBC exercises, by taking into account the changes in load moment arm and muscle length elicited by each dumbbell curl protocol. A single cycle (concentric-eccentric) of DBC, IDC and DPC, was applied to 22 subjects using a submaximal load of 40% estimated from an isometric MVC test. The neuromuscular activity of biceps brachii long head was compared by further partitioning each contraction into three phases, according to individual elbow joint range of motion. Although all protocols elicited a considerable level of activation of the biceps brachii muscle (at least 50% of maximum RMS), the contribution of this muscle for elbow flexion/extension varied among exercises. The submaximal elbow flexion (concentric) elicited neuro muscular activity up to 95% of the maximum RMS value during the final phase of IDC and DBC and 80% for DPC at the beginning of the movement. All exercises showed significant less muscle activity for the elbow extension (eccentric). The Incline Dumbbell Curl and the classical Dumbbell Biceps Curl resulted in similar patterns of biceps brachii activation for the whole range of motion, whereas Dumbbell Preacher Curl elicited high muscle activation only for a short range of elbow joint angle. Key pointsThe Incline Dumbbell Curl and the Dumbbell Biceps Curl resulted in a considerable neuromuscular effort throughout the whole elbow range of motion.The Incline Dumbbell Curl and the Dumbbell Biceps Curl may be preferable for the improvement of biceps brachii force in training programs. PMID:24150552

Oliveira, Liliam F; Matta, Thiago T; Alves, Daniel S; Garcia, Marco A C; Vieira, Taian M M

2009-01-01

159

First report of Tomato Yellow Leaf Curl China Virus infecting Panax Notoginseng in China  

Technology Transfer Automated Retrieval System (TEKTRAN)

Panax notoginseng, an important medicinal herb commonly known as notoginseng, san qi or tian qi, is a species of the genus Panax in the family Araliaceae. The herb is mainly cultivated in Guangxi and Yunnan Provinces of southern China for its root, which is used to treat blood disorders such as bloo...

160

Bees visiting squash (Cucurbita moschata Duchesne ex Poiret) in southwestern Colombia (Hymenoptera: Apoidea)  

E-print Network

This note records for the first time 12 bee species belonging to eight genera of Apidae and Halictidae as visitors of cultivated squash (Cucurbita moschata Duchesne ex Poiret: Cucurbitaceae) in the municipality of El Patía, Department of Cauca...

Zambrano-G, Giselle; Gonzalez, Victor H.; Hinojosa-Diaz, Ismael A.; Engel, Michael S.

2013-10-07

161

Curling edges: a problem that has plagued scrolls for millennia.  

PubMed

Qi-Wa refers to the up curl on the lengths of hand scrolls and hanging scrolls, which has troubled Chinese artisans and emperors for as long as the art of painting and calligraphy has existed. This warp is unwelcome not only for aesthetic reasons, but its potential damage to the fiber and ink. Although it is generally treated as a part of the cockling and curling due to moisture, consistency of paste, and defects from the mounting procedures, we demonstrate that the spontaneous extrinsic curvature incurred from the storage is in fact more essential to understanding and curing Qi-Wa. In contrast to the former factors whose effects are less predictable, the plastic deformation and strain distribution on a membrane are a well-defined mechanical problem. We study this phenomenon by experiments, theoretical models, and molecular dynamics simulation, and obtain consistent scaling relations for the Qi-Wa height. This knowledge enables us to propose modifications on the traditional mounting techniques that are tested on real mounted paper to be effective at mitigating Qi-Wa. By experimenting on polymer-based films, we demonstrate the possible relevance of our study to the modern development of flexible electronic paper. PMID:24484142

Chou, Ming-Han; Shen, Wei-Chao; Wang, Yi-Ping; Hung, Sun-Hsin; Hong, Tzay-Ming

2014-01-24

162

Helmholtz-Hodge Decomposition on [0, 1]d Divergence-free and Curl-free Wavelets  

E-print Network

Helmholtz-Hodge Decomposition on [0, 1]d by Divergence-free and Curl-free Wavelets Souleymane Kadri´esum´e This paper deals with the Helmholtz-Hodge decomposition of a vector field in bounded domain. We present of the method. Keywords: Divergence-free and curl-free wavelets ; Helmholtz-Hodge decomposition. 1 Introduction

Paris-Sud XI, Université de

163

Effect of fibre curl on the properties of wood pulp fibre-cement and silica sheets  

Microsoft Academic Search

Curl has been induced in unbleached softwood kraft pulp fibres by treatment in the laboratory at 20% consistency in a planetary mixer. Steam treatment of the fibres to set the curl more strongly was found to be detrimental to fibre properties as deduced from handsheet properties. A means of producing two-ply specimens in the laboratory was devised and a tensile

A. J. Michell; G. Freischmidt

1990-01-01

164

N=2 SUSY on an $SU(2)\\times U(1)$ Isometric Squashed $S^4$  

E-print Network

We study N = 2 supersymmetric theory on a large family of squashed 4-spheres preserving $SU(2)\\times U(1)$ isometry and determine the conditions under which this background is supersymmetric. We then compute the partition function of this theory using localization technique. The results indicate that for N = 2 SUSY including both vector-multiplets and hypermultiplets, the partition function is independent of the arbitrary squashing functions as well as of the other supergravity background fields.

Cabo-Bizet, Alejandro; Giraldo-Rivera, V I; Muteeb, M Nouman; Narain, K S

2014-01-01

165

N=2 SUSY on an $SU(2)\\times U(1)$ Isometric Squashed $S^4$  

E-print Network

We study N = 2 supersymmetric theory on a large family of squashed 4-spheres preserving $SU(2)\\times U(1)$ isometry and determine the conditions under which this background is supersymmetric. We then compute the partition function of this theory using localization technique. The results indicate that for N = 2 SUSY including both vector-multiplets and hypermultiplets, the partition function is independent of the arbitrary squashing functions as well as of the other supergravity background fields.

Alejandro Cabo-Bizet; Edi Gava; V. I. Giraldo-Rivera; M. Nouman Muteeb; K. S. Narain

2014-12-21

166

Multiple categories of resistance to wheat curl mite (Acari: Eriophyidae) expressed in accessions of Aegilops tauschii.  

PubMed

The wheat curl mite, Aceria tosichella Keifer, is an important pest in the western plains of the United States as well as in most major wheat-growing regions of the world. This mite is a vector of the economically important diseases wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV), and High Plains virus (HPV). This study looked at seven accessions of Aegilops tauschii (Coss) Schmal to determine if they exhibit antibiosis, tolerance, and/or antixenosis to the wheat curl mite using 'Jagger', a known wheat curl mite-susceptible variety, and OK05312, a known wheat curl mite-resistant variety, as controls. Four of the seven tested accessions showed antibiotic effects on the population growth of wheat curl mite, as demonstrated by low number of wheat curl mite adults and nymphs at the end of the experiment. Three accessions and the commercial wheat variety Jagger showed some level of tolerance to wheat curl mite infestations, as demonstrated by a significantly reduced percentage proportional tissue dry weight and by tolerance index values. Four accessions demonstrated a strong antixenotic effect on the wheat curl mite, as demonstrated by significantly reduced numbers of mite adults at the end of the experiment. This study also established an effective method for determining antixenosis to the wheat curl mite in wheat that can be used for future experiments. All accessions demonstrated at least one type of plant resistance that could provide a genetic source for control of the wheat curl mite that may have the potential to be transferred into commercial wheat varieties. PMID:23356085

Carrera, Sandra Garcés; Davis, Holly; Aguirre-Rojas, Lina; Murugan, Marimuthu; Smith, C Mike

2012-12-01

167

FIRST REPORT OF BACTERIAL LEAF SPOT ON LEAFY BRASSICA GREENS CAUSED BY PSEUDOMONAS SYRINGAE PV. MACULICOLA IN SOUTH CAROLINA  

Technology Transfer Automated Retrieval System (TEKTRAN)

As of 2001, South Carolina ranked second in the United States in acreage of turnip greens (Brassica rapa) and collard (B. oleracea) and third in acreage of mustard (B. juncea). In June 2001, a leaf disease was found on turnip greens (cv. Alamo), mustard (cv. Southern Giant Curled and Florida Broadl...

168

7 CFR 319.56-48 - Conditions governing the entry of baby squash and baby courgettes from Zambia.  

Code of Federal Regulations, 2010 CFR

...Dacus ciliatus, Dacus frontalis, Dacus lounsburyii, Dacus punctatifrons, Dacus vertebratus, Diaphania indica, Helicoverpa armigera, and Spodoptera littoralis. (a) Approved greenhouses. The baby squash and baby courgettes must...

2010-01-01

169

Leaf Identification  

NSDL National Science Digital Library

This straightforward tutorial on leaf identification comes from the Department of Horticulture at Penn State University. Simple diagrams, helpful photos, and clear explanations make short work of learning the basics of leaf identification. The website even includes a section on why anyone should bother learning this skill (i.e. it's not just for dedicated horticulturists and botanists). The tutorial covers leaf structure, blade shape, margins, venation, and so on. The self-testing component appears to be unavailable at this time, but this site as a whole is definitely worth a look.

170

Curled actuated shapes of ionic polymer metal composites strips  

NASA Astrophysics Data System (ADS)

The curled actuated shapes of ionic polymer metal composites (IPMCs) are described within a nonlinear physics-based model of IPMC actuators. A key characteristic of the model is the refined, even if black box based, modeling of the relative permittivity of the IPMCs which strongly influences the actuation performances of the IPMC, when voltages higher than 1 V are involved. A varying-along-the-thickness relative permittivity is proposed to take into account the highly heterogeneous layers resulting from electrode deposition, where a charge redistribution occurs. Moreover, the presence of the metal electrodes has been considered as hampering the IPMCs' bending deformations, so reducing the actuation performances of the IPMC. A series of numerical tests have been planned and discussed to show the characteristics of the model; in particular, the model is shown to be strong enough to catch the not monotonic behavior of IPMCs, when back relaxation is manifested.

Nardinocchi, Paola; Pezzulla, Matteo

2013-06-01

171

Leaf Arrangement  

NSDL National Science Digital Library

This illustrated guide to leaf arrangement shows students how leaves attached at a stem node can be in alternate, opposite, or whorled arrangements. This single Web page can be easily printed for use at field sites.

172

Dental squash injuries - a survey among players and coaches in Switzerland, Germany and France.  

PubMed

Squash belongs to sporting activities with medium risk of causing dental trauma. Because of high velocity, close body contact and the use of rackets the injury potential in squash has increased. The aim of this work was to conduct a comparative study between Switzerland, Germany and France on a number of issues: the frequency of dental and facial injuries in squash, athletes' habits of wearing mouthguards, as well as the general level of information about emergency measures after a dental trauma and the resulting consequences. Using a standardized questionnaire a total of 653 individuals, 600 squash players and their 53 coaches, were interviewed. In each of the three countries 200 players belonging to four different divisions (juniors, amateurs, semi-professionals and professionals) were surveyed. Of these 653 interviewees 133 (20.4%) have already observed a dental injury; 27 (4.5%) have experienced a dental trauma themselves. Less than half of all interviewed players and coaches (47.6%) were aware of the possibility of replanting avulsed teeth. Just 5.1% were familiar with the tooth rescue kit. Only one individual wore a mouthguard. The results show that the area of squash requires more information about prevention through sports associations, coaches and dentists. PMID:16942551

Persic, Robert; Pohl, Yango; Filippi, Andreas

2006-10-01

173

Curling during desiccation protects the foliose lichen Lobaria pulmonaria against photoinhibition  

Microsoft Academic Search

This study aims to assess the photoprotective potential of desiccation-induced curling in the light-susceptible old forest\\u000a lichen Lobaria pulmonaria by using chlorophyll fluorescence imaging. Naturally curled thalli showed less photoinhibition-induced limitations in primary\\u000a processes of photosynthesis than artificially flattened specimens during exposures to 450 ?mol m?2 s?1 in the laboratory after both 12- (medium dose treatment) and 62-h duration (high dose treatment). Thallus

Miloš Barták; Knut Asbjørn Solhaug; Hana Vráblíková; Yngvar Gauslaa

2006-01-01

174

SHAPESET: A process to reduce sidewall curl springback in high-strength steel rails  

Microsoft Academic Search

High-strength steel rails for structural members can reduce vehicle weight, but sidewall curl springback in these rails causes\\u000a assembly difficulties with adjacent parts. A process to greatly reduce curl springback, known as SHAPESET, was investigated\\u000a for a variety of high-strength steels, including two dual-phase steels. Gridded blanks were stamped by the two-step SHAPESET\\u000a process and by conventional methods. The SHAPESET

R. A. Ayres

1984-01-01

175

Leaf Development  

PubMed Central

Leaves are the most important organs for plants. Without leaves, plants cannot capture light energy or synthesize organic compounds via photosynthesis. Without leaves, plants would be unable perceive diverse environmental conditions, particularly those relating to light quality/quantity. Without leaves, plants would not be able to flower because all floral organs are modified leaves. Arabidopsis thaliana is a good model system for analyzing mechanisms of eudicotyledonous, simple-leaf development. The first section of this review provides a brief history of studies on development in Arabidopsis leaves. This history largely coincides with a general history of advancement in understanding of the genetic mechanisms operating during simple-leaf development in angiosperms. In the second section, I outline events in Arabidopsis leaf development, with emphasis on genetic controls. Current knowledge of six important components in these developmental events is summarized in detail, followed by concluding remarks and perspectives. PMID:23864837

2013-01-01

176

Assessment of Aegilops tauschii for resistance to biotypes of wheat curl mite (Acari: Eriophyidae).  

PubMed

Aegilops tauschii, the wild diploid D-genome progenitor of wheat, Triticum aestivum L., is an important source of resistance to several arthropod pests and pathogens. A total of 108 Ae. tauschii accessions from different geographic regions were evaluated for resistance to biotypes of the wheat curl mite, Aceria tosichella Keifer, from Kansas, Nebraska, and Montana. The wheat curl mite is the only vector known to transmit wheat streak mosaic virus. Wheat curl mite resistance was detected in germplasm from all the geographic locations represented. The highest percentage of resistant accessions originated from Turkey, followed by Afghanistan and the Caspian Sea region of Iran. Sixty-seven percent of the accessions exhibited resistance to at least one wheat curl mite biotype and 19% were resistant to all the three biotyopes. Resistance to the accessions tested occurred more frequently in the Nebraska and Kansas biotypes (69% and 64%, respectively) than did resistance to the Montana biotype (42%), although the frequency of resistance was not significant. The differential reactions of accessions to the different wheat curl mite biotypes suggests that Ae. tauschii has at least five different genes for resistance to mite colonization. Ae. tauschii continues to be a very useful source for wheat curl mite resistance genes for bread wheat improvement. PMID:14503608

Malik, Renu; Smith, C Michael; Brown-Guedira, Gina L; Harvey, Tom L; Gill, Bikram S

2003-08-01

177

Leaf Living  

NSDL National Science Digital Library

In this outdoor fall activity, learners find out what living in or under a layer of leaves is like. Learners will discover that animals that live in leaf litter use different senses to find prey, avoid predators, and to navigate through the litter. Learners role play predator and prey—the "prey" hides in a large pile of leaves, and the "predator" tries to "strike" by reaching straight into the leaf pile to grab the "prey." Learners also consider what body adaptations help organisms that spend part of their life under the leaves.

Lawrence Hall of Science

1981-01-01

178

Cytologic features of the normal pineal gland on squash preparations.  

PubMed

As primary pineal lesions are extremely rare, many surgical pathologists are unfamiliar with normal pineal cytologic features. We describe cytologic features of the normal pineal gland in patients of varying ages and identify common diagnostic pitfalls. We performed a retrospective review of pineal gland biopsies performed at our institution, where approximately 30,000 surgical specimens are accessioned yearly, for the last 23 years. Only two pineal gland biopsies were found. Although both cases were initially diagnosed as low-grade gliomas on frozen section, the final diagnosis was benign pineal tissue based on light microscopy and immunohistochemistry results. Additionally, we performed squash preparations of five normal pineal gland autopsy specimens with Papanicolaou and Diff-Quik® (Dade Behring, Newark, DE) stains. Infant preparations were highly cellular smears composed of numerous, uniform, single cells with indistinct cytoplasm, small round-to-oval nuclei, fine chromatin, and absent nucleoli and calcifications. The vague microfollicular pattern mimicked a pineocytoma and the fine fibrillary background mimicked a glial neoplasm. Young adult smears were similar; however, microcalcifications were present with fewer background single cells. Older patients had much less cellular smears composed of small clusters of cells with fusiform-to-spindle nuclei, a fine chromatin pattern, and indistinct cytoplasmic borders. There were fewer background single cells and more microcalcifications. The cytologic features of the native pineal gland vary with age. Normal pineal tissue can be confused with a pineocytoma or low-grade glioma. Familiarity with normal pineal gland cytological features will help to avoid a potential misdiagnosis. PMID:24692343

Murro, Diana; Alsadi, Alaa; Nag, Sukriti; Arvanitis, Leonidas; Gattuso, Paolo

2014-11-01

179

Strong gravitational lensing in a charged squashed Kaluza-Klein Gödel black hole  

NASA Astrophysics Data System (ADS)

In this Letter we investigate the strong gravitational lansing in a charged squashed Kaluza-Klein Gödel black hole. The deflection angle is considered by the logarithmic term proposed by Bozza et al. Then we study the variation of deflection angle and its parameters abar and bbar. We suppose that the supermassive black hole in the galaxy center can be considered by a charged squashed Kaluza-Klein black hole in a Gödel background. Then by the relations between lensing parameters and observables, we estimate the observables for different values of charge, extra dimension and Gödel parameters.

Sadeghi, J.; Naji, J.; Vaez, H.

2014-01-01

180

Leaf Type  

NSDL National Science Digital Library

This illustrated guide to leaf types is designed to help students understand the differences between compound and simple leaves. This single Web page can be easily printed for use at field sites. Along with an explanation of both types, the guide includes a short description of related terms.

181

The inheritance of white fruit and stem color in summer squash Cucurbita pepo L  

Microsoft Academic Search

White fruited plants from the variety “White bush” were crossed to green and striped fruit in order to study the inheritance of white fruit in summer squash. The genetic ratio suggested that green fruit is controlled by two genes, C and R, and that one (C) has a dominant epistatic control. The white fruit is determined as ccrr. A third

D. Globerson

1969-01-01

182

2011-12 PROSPECTUS2011-12 PROSPECTUS WESLEYAN WOMEN'S SQUASHWESLEYAN WOMEN'S SQUASH  

E-print Network

2011-12 PROSPECTUS2011-12 PROSPECTUS WESLEYAN WOMEN'S SQUASHWESLEYAN WOMEN'S SQUASH #12;Director......Jason Helbig Facility Manager/Asst. AD ....Erin Carey Fitness Center Director......Drew Black Intramural........................Phil Carney Women's Crew...................Pat Tynan M/W Cross Country ...........John Crooke Field Hockey

Devoto, Stephen H.

183

Functional immunomics of the squash bug, Anasa tristis (De Geer) (Heteroptera: Coreidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Squash bug, Anasa tristis (De Geer), is a major piercing/sucking pest of cucurbits causing extensive damage to plants and fruits, and transmitting phytopathogens. There are few effective biological control agents or cultural practices for controlling this highly destructive pest. A promising n...

184

Detection of yellow vine disease in squash and pumpkin in Massachusetts  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two commercial plots of summer squash in Charlemont, Franklin County, MA were devastated in 1999 by 100% incidence of a yellowing disease resembling cucurbit yellow vine. Both plots were established during the third week of May, one with transplants and the second by direct-seeding. The plots consis...

185

Hawking radiation in a rotating Kaluza-Klein black hole with squashed horizons  

SciTech Connect

We explore the signature of the extra dimension in the Hawking radiation in a rotating Kaluza-Klein black hole with squashed horizons. Comparing with the spherical case, we find that the rotating parameter brings richer physics. We obtain the appropriate size of the extra dimension which can enhance the Hawking radiation and may open a window to detect the extra dimensions.

Chen Songbai; Wang Bin; Su Rukeng [Department of Physics, Fudan University, Shanghai 200433 (China) and Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China); Department of Physics, Fudan University, Shanghai 200433 (China); China Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, Beijing 100080 (China) and Department of Physics, Fudan University, Shanghai 200433 (China)

2008-01-15

186

Efficient plant regeneration via organogenesis in winter squash ( Cucurbita maxima Duch.)  

Microsoft Academic Search

Using cotyledonary explants excised from seedlings germinated in vitro, efficient plant regeneration via organogenesis was established for two winter squash (Cucurbita maxima Duch.) cultivars. To establish optimal conditions for adventitious shoot induction, a variety of explants were prepared from seedlings of different ages and these were cultured using media containing different concentrations of 6-benzylaminopurine (BA). For both cultivars, plant regeneration

Young Koung Lee; Won Il Chung; Hiroshi Ezura

2003-01-01

187

Potential organic herbicides for squash production: Pelargonic acid herbicides AXXE (registered trademark) and Scythe (registered trademark)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season- long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of potential organic herbicides on weed control efficacy, crop injury, and y...

188

Pelargonic acid formulations, application rates, and sequential applications for weed control in squash  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season- long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of potential organic herbicides on weed control efficacy, crop injury, and y...

189

Weed control in yellow squash using sequential postdirected applications of pelargonic acid  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash (Cucurbita pepo L.) producers would benefit from appropriate herbicides that can effectively provide season-long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) during 2010 and 2011 to determine the impact of a naturally derived herbicide on weed control ef...

190

Responses of various vining cucurbits to Squash vein yellowing virus infection  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV) induced watermelon vine decline is a major limitation to watermelon production in Florida. The symptoms of this disease are a systemic wilt and necrosis which spreads along the vines of plants and leads to complete collapse. Fruit on affected vines also often sh...

191

Wheat curl mite (Acari: Eriophyidae) dispersal and its relationship with kernel red streaking in maize.  

PubMed

Wheat curl mites, Aceria tosichella Keifer, dispersing from wheat (Triticum spp.) to nearby corn (Zea mays L.) fields play a role in the development of kernel red streaking in corn. These studies were undertaken to verify the relationship of wheat curl mite to kernel red streaking, to determine whether wheat is the main source of curl mites dispersing into corn and to determine whether planting corn in temporal or spatial isolation of wheat is a valid management strategy. These studies were conducted on farm fields using sticky traps to monitor mites, followed by sampling mature grain for kernel streaking in southwestern Ontario from 1999 to 2002. The dominant source mites were winter wheat. Mite dispersal occurred during the first 3 wk of winter wheat maturation after the wheat had reached Zadoks stage 87. Mite dispersal corresponded to prevailing winds in the area with the lowest number of mites and the lowest severity of kernel red streaking occurring 60 m from wheat fields planted to the north, south, and east of cornfields and 90 m from wheat fields planted to the west of cornfields. The severity of kernel red streaking was positively correlated with the density of wheat curl mites in corn; however, the correlation was weak and kernel red streaking was still high in many cornfields when few or no mites were present. These findings suggest that wheat curl mite migration into corn is not entirely predictive of the incidence and severity of kernel red streaking. PMID:16334327

Liu, J; Lee, E A; Sears, M K; Schaafsma, A W

2005-10-01

192

Curling during desiccation protects the foliose lichen Lobaria pulmonaria against photoinhibition.  

PubMed

This study aims to assess the photoprotective potential of desiccation-induced curling in the light-susceptible old forest lichen Lobaria pulmonaria by using chlorophyll fluorescence imaging. Naturally curled thalli showed less photoinhibition-induced limitations in primary processes of photosynthesis than artificially flattened specimens during exposures to 450 micromol m-2 s-1 in the laboratory after both 12- (medium dose treatment) and 62-h duration (high dose treatment). Thallus areas shaded by curled lobes during light exposure showed unchanged values of measured chlorophyll fluorescence parameters (FV/FM, PhiPS II), whereas non-shaded parts of curled thalli, as well as the mean for the entire flattened thalli, showed photoinhibitory limitation after light treatments. Furthermore, the chlorophyll fluorescence imaging showed that the typical small-scale reticulated ridges on the upper side of L. pulmonaria caused a spatial, small-scale reduction in damage due to minor shading. Severe dry-state photoinhibition readily occurred in flattened and light-treated L. pulmonaria, although the mechanisms for such damage in a desiccated and inactive stage are not well known. Natural curling is one strategy to reduce the chance for serious photoinhibition in desiccated L. pulmonaria thalli during high light exposures. PMID:16804701

Barták, Milos; Solhaug, Knut Asbjørn; Vráblíková, Hana; Gauslaa, Yngvar

2006-10-01

193

Specificity and Photomorphogenic Nature of Ultraviolet-B-Induced Cotyledon Curling in Brassica napus L.  

PubMed Central

Three general classes of photomorphogenic photoreceptors have been characterized in higher plants: phytochrome, a blue light/ultraviolet (UV)-A photoreceptor(s), and a UV-B sensory system(s). Although a great deal is known about phytochrome and the blue light/UV-A photoreceptor(s), little is known about UV-B detection processes. One reason for this is the lack of readily quantifiable morphogenic responses that are specifically induced by UV-B radiation. We have discovered a response to UV-B, upward curling of Brassica napus L. cotyledons, that may be useful for probing the mechanism of UV-B photoreception. The process was initially observed when B. napus seeds were germinated under visible light plus UV-B radiation, but did not occur under visible light alone or visible light plus UV-A. When 5-d-old seedlings grown in visible light were given relatively short exposures of UV-B (100 min of 5.5 [mu]mol m-2 s-1), the curling response was also observed. Development of curling was separated from the application of this UV-B pulse by a 14-h latent period. Pulses of red light, blue light, farred light, and UV-A (100 min of 5.5 [mu]mol m-2 s-1) did not induce curling, indicating UV-B specificity Additionally, these other spectral regions did not reverse or enhance the UV-B-triggered response. The degree of curling showed a log-linear dependence on UV-B fluence (6-40 mmol m-2) and reciprocity with respect to length of exposure and fluence rate. The data indicate that curling is photomorphogenic in nature and may be triggered by a single photoreceptor species. PMID:12231857

Wilson, M. I.; Greenberg, B. M.

1993-01-01

194

75 FR 29309 - Notice of Decision to Issue Permits for the Importation of Fresh Male Summer Squash Flowers From...  

Federal Register 2010, 2011, 2012, 2013, 2014

...designated phytosanitary measures will be sufficient to mitigate the risks of introducing or disseminating plant pests or noxious weeds via the importation of fresh male summer squash flowers from Israel. EFFECTIVE DATE: May 25, 2010. FOR FURTHER...

2010-05-25

195

Tree Leaf Identification and Leaf Display Activity  

NSDL National Science Digital Library

This activity is a tree leaf collection, identification, and display of dried and pressed leaves. It teaches students about distinguishing leaf characteristics as well as a way to display and label their collection.

Hansing, Rebecca

196

A deformation of quantum affine algebra in squashed Wess-Zumino-Novikov-Witten models  

SciTech Connect

We proceed to study infinite-dimensional symmetries in two-dimensional squashed Wess-Zumino-Novikov-Witten models at the classical level. The target space is given by squashed S{sup 3} and the isometry is SU(2){sub L}?×?U(1){sub R}. It is known that SU(2){sub L} is enhanced to a couple of Yangians. We reveal here that an infinite-dimensional extension of U(1){sub R} is a deformation of quantum affine algebra, where a new deformation parameter is provided with the coefficient of the Wess-Zumino term. Then we consider the relation between the deformed quantum affine algebra and the pair of Yangians from the viewpoint of the left-right duality of monodromy matrices. The integrable structure is also discussed by computing the r/s-matrices that satisfy the extended classical Yang-Baxter equation. Finally, two degenerate limits are discussed.

Kawaguchi, Io; Yoshida, Kentaroh [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2014-06-15

197

Orthogonal Helmholtz decomposition in arbitrary dimension using divergence-free and curl-free wavelets  

E-print Network

Orthogonal Helmholtz decomposition in arbitrary dimension using divergence-free and curl projectors. These projectors enable the construction of an iterative algorithm to compute the Helmholtz to the Helmholtz decomposition cal- culated by Fourier transform. Then we prove the convergence of the algorithm

Starck, Jean-Luc

198

Identification of the Wheat Curl Mite as the Vector of Triticum Mosaic Virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Triticum mosaic virus (TriMV) is a newly discovered virus found infecting wheat (Triticum aestivum L.) in Kansas. This study was conducted to determine if the wheat curl mite (WCM, Aceria tosichella Keifer) and the bird cherry oat aphid (Rhopalosiphum padi L. ) could transmit TriMV. Using diffe...

199

Global spread of wheat curl mite by the most polyphagous and pestiferous lineages  

Technology Transfer Automated Retrieval System (TEKTRAN)

The wheat curl mite (WCM), Aceria tosichella, is an important pest of wheat and other cereal crops that transmits wheat streak mosaic virus and several other plant viruses. WCM has long been considered a single polyphagous species, but recent studies in Poland revealed a complex of genetically disti...

200

SURVIVAL OF WHEAT CURL MITES ON DIFFERENT SOURCES OF RESISTANCE IN WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat yield is limited by wheat streak mosaic virus which is vectored by the wheat curl mite (WCM) Aceria tosicheilla (Keifer).Host resistance to WCM has reduced losses. This study evaluated the effectiveness of resistance in wheat to WCM collected from various locations in the Great Plains. Collect...

201

Three dimensional musculoskeletal modelling of the seated biceps curl resistance training exercise.  

PubMed

The aim of this study was to evaluate the benefits and limitations of using three dimensional (3D) musculoskeletal modelling (LifeModeler) in assessing the safety and efficacy of exercising on a seated biceps curl resistance training machine. Three anthropometric cases were studied, representing a 5th percentile female, 50th percentile and 95th percentile male. Results indicated that the LifeModeler default model was not adequate to solve the forward dynamics simulations. Therefore adjustments had to be made to the default model to successfully complete the forward dynamics simulations. The software was able to sufficiently highlight the shortcomings of the biceps curl machine's engineered adjustability in relation to the anthropometric dimensions of the studied cases, as the 5th percentile female could not be accommodated suitably on the machine. High lumbar spine anterior/posterior shear forces for all anthropometric cases and maximum muscle tensions for the female and 50th percentile male indicate that the seated biceps curl exercise may pose risks for injuries. To conclude, it appears that 3D musculoskeletal modelling can be used to evaluate resistance training equipment such as the seated biceps curl machine. However the limitations as indicated by this study must be taken into consideration, especially when using the default LifeModeler model. PMID:21834398

Nolte, Kim; Krüger, Pieter E; Els, P Schalk

2011-06-01

202

Differential transmission of Triticum mosaic virus by wheat curl mite populations collected in the Great Plains  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat is an important food grain worldwide, and the primary dryland crop in the western Great Plains. A complex of three wheat curl mite (WCM)-transmitted viruses [Wheat streak mosaic, High plains, and Triticum mosaic viruses (TriMV)] is a cause of serious loss in winter wheat production in the Grea...

203

Self-Similar Curling of a Naturally Curved Elastica A. C. Callan-Jones,1  

E-print Network

, France 3 Laboratoire FAST, UPMC-Paris 6, Universite´ Paris-Sud, CNRS, Ba^timent 502, Campus Universitaire of some plants; the tendrils of Bryonia Dioica respond to touch stimuli by curling [1]. The membrane at the end s ¼ L and released at the other end, s ¼ 0, and its motion was imaged using a Photron fast camera

Audoly, Basile

204

Gravity dual of supersymmetric gauge theories on a squashed five-sphere.  

PubMed

We present the gravity dual of large N supersymmetric gauge theories on a squashed five-sphere. The one-parameter family of solutions is constructed in Euclidean Romans F(4) gauged supergravity in six dimensions, and uplifts to massive type IIA supergravity. By renormalizing the theory with appropriate counterterms we evaluate the renormalized on-shell action for the solutions. We also evaluate the large N limit of the gauge theory partition function, and find precise agreement. PMID:25325628

Alday, Luis F; Fluder, Martin; Richmond, Paul; Sparks, James

2014-10-01

205

Gravity Dual of Supersymmetric Gauge Theories on a Squashed Five-Sphere  

NASA Astrophysics Data System (ADS)

We present the gravity dual of large N supersymmetric gauge theories on a squashed five-sphere. The one-parameter family of solutions is constructed in Euclidean Romans F(4) gauged supergravity in six dimensions, and uplifts to massive type IIA supergravity. By renormalizing the theory with appropriate counterterms we evaluate the renormalized on-shell action for the solutions. We also evaluate the large N limit of the gauge theory partition function, and find precise agreement.

Alday, Luis F.; Fluder, Martin; Richmond, Paul; Sparks, James

2014-10-01

206

Evaluation of systemic acquired resistance inducers for control of Phytophthora capsici on squash  

Microsoft Academic Search

Phytophthora blight induced by Phytophthora capsici is a major constraint in vegetable production worldwide. Limited information is available regarding potential systemic acquired resistance (SAR) inducers that may provide protection of squash (Cucurbita pepo) plants against the disease and the direct effect of the products on the pathogen. In this study, the effect of DL-3-aminobutyric acid (BABA), 2,6-dichloroisonicotinic acid (INA), Saver

D. Koné; A. S. Csinos; K. L. Jackson; P. Ji

2009-01-01

207

Strong gravitational lensing in a squashed Kaluza-Klein black hole spacetime  

SciTech Connect

We investigate the strong gravitational lensing in a Kaluza-Klein black hole with squashed horizons. We find the size of the extra dimension imprints in the radius of the photon sphere, the deflection angle, the angular position, and magnification of the relativistic images. Supposing that the gravitational field of the supermassive central object of the Galaxy can be described by this metric, we estimated the numerical values of the coefficients and observables for gravitational lensing in the strong field limit.

Liu Yue; Chen Songbai; Jing Jiliang [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China) and Key Laboratory of Low Dimensional Quantum Structures and Quantum Control (Hunan Normal University), Ministry of Education (China)

2010-06-15

208

Quasinormal modes of charged squashed Kaluza-Klein black holes in the Goedel universe  

SciTech Connect

We study the quasinormal modes of scalar perturbation in the background of five-dimensional charged Kaluza-Klein black holes with squashed horizons immersed in the Goedel universe. Besides the influence due to the compactness of the extra dimension, we disclose the cosmological rotational effect in the wave dynamics. The wave behavior affected by the Goedel parameter provides an interesting insight into the Goedel universe.

He Xi; Wang Bin; Chen Songbai [Department of Physics, Fudan University, 200433 Shanghai (China); Institute of Physics and Department of Physics, Hunan Normal University, Changsha, 410081 Hunan (China)

2009-04-15

209

A new method for assessing squash tactics using 15 court areas for ball locations.  

PubMed

Tactics in squash have typically been assessed using the frequency of different shot types played at different locations on the court either without reference to other relevant information or on the basis of the preceding shot. This paper presents a new squash specific method for categorizing court locations in which the ball was played, a novel techniques for assessing the reliability of this method and presents typical shots responses in these new areas controlled for preceding shot as well as the time between shots and the handedness of the players. Twelve games were viewed using the SAGIT/Squash software and 2907 shots viewed a second time from a video image taken from behind the court with an overall agreement of 88.90% for the court location data and 99.52% for shot type. 3192 shots from 9 matches from the 2003 World Team Championships were analyzed in SAGIT/Squash. In the court areas analyzed between 2 and 7 shot responses were predominant suggesting tactical patterns were evident. This was supported by differences evident between shot responses played from the two back corners where the backhand side was characterized by a predominance of straight drives whereas straight and crosscourt drives were played on the forehand side. These results tended to confirm that tactics i.e., consistent shot types, are played although these are only apparent when factors that determine shot selection are accounted for. This paper has controlled for some of these factors but others need to be considered e.g., if individual player profiles are to be ascertained. PMID:24548850

Vu?kovi?, Goran; James, Nic; Hughes, Mike; Murray, Stafford; Milanovi?, Zoran; Perš, Janez; Sporiš, Goran

2014-04-01

210

Squash preparation: A reliable diagnostic tool in the intraoperative diagnosis of central nervous system tumors  

PubMed Central

Background: Intraoperative cytology is an important diagnostic modality improving on the accuracy of the frozen sections. It has shown to play an important role especially in the intraoperative diagnosis of central nervous system tumors. Aim: To study the diagnostic accuracy of squash preparation and frozen section (FS) in the intraoperative diagnosis of central nervous system (CNS) tumors. Materials and Methods: This prospective study of 114 patients with CNS tumors was conducted over a period of 18 months (September 2004 to February 2006). The cytological preparations were stained by the quick Papanicolaou method. The squash interpretation and FS diagnosis were later compared with the paraffin section diagnosis. Results: Of the 114 patients, cytological diagnosis was offered in 96 cases. Eighteen nonneoplastic or noncontributory cases were excluded. Using hematoxylin and eosin-stained histopathology sections as the gold standard, the diagnostic accuracy of cytology was 88.5% (85/96) and the accuracy on FS diagnosis was 90.6% (87/96). Among these cases, gliomas formed the largest category of tumors (55.2%). The cytological accuracy in this group was 84.9% (45/53) and the comparative FS figure was 86.8% (46/53). In cases where the smear and the FS diagnosis did not match, the latter opinion was offered. Conclusions: Squash preparation is a reliable, rapid and easy method and can be used as a complement to FS in the intraoperative diagnosis of CNS tumors. PMID:21187881

Mitra, Sumit; Kumar, Mohan; Sharma, Vivek; Mukhopadhyay, Debasis

2010-01-01

211

Inhibition of serine proteases of the blood coagulation system by squash family protease inhibitors.  

PubMed

Squash family inhibitors are the smallest protein serine protease inhibitors, being composed of approximately 30 amino acid residues. We isolated 8 squash family inhibitors from the seeds of bitter gourd, squash, gourd and luffa and examined their effect on serine proteases of the blood coagulation system. Five of them prolonged the activated partial thromboplastin time of human plasma to various extents, but three did not. Only Momordica charantia (bitter gourd) trypsin inhibitor-II prolonged the prothrombin time of human plasma. All inhibitors inhibited the amidolytic activities of factor XIIa, plasma kallikrein, factor Xa, but did not inhibit significantly those of factor XIa, factor IXa, factor VIIa, and thrombin. Ki values for factor XIIa, plasma kallikrein, and factor Xa were in the order of 10(-6)-10(-9), 10(-4)-10(-5), and 10(-4)-10(-6)M, respectively. The prolongation of the activated partial thromboplastin time by inhibitors appeared to correspond to their inhibitory potencies for factor XIIa. Momordica charantia trypsin inhibitor-II, which has the strongest inhibitory potency toward the amidolytic activity of factor Xa, with a Ki value 10-100 times smaller than those of other inhibitors, inhibited the activation of factor X by factor VIIa-tissue factor complex or factor IXa, while others did not. PMID:7896727

Hayashi, K; Takehisa, T; Hamato, N; Takano, R; Hara, S; Miyata, T; Kato, H

1994-11-01

212

Leaf Modeling and Constrained Leaf Morphing in Leaf Space Saurabh Garg1  

E-print Network

Leaf Modeling and Constrained Leaf Morphing in Leaf Space Saurabh Garg1 , Leow Wee Kheng1 1 School@comp.nus.edu.sg Morphing from an elliptic leaf (first row, first image) to a deltoid leaf (second row, last image) with a constraint of a leaf with both basal and apical extension (second row, first image). Abstract Leaf modeling

Leow, Wee Kheng

213

EFFECTS OF METHYL JASMONATE AND SUPERATMOSPHERIC OXYGEN LEVELS ON ALTERNATIVE OXIDASE IN LOW TEMPERATURE STORED GREEN PEPPER (CAPSICUM ANNUUM L.) AND ZUCCHINI SQUASH (CUCURBITA PEPO L.)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Quality was improved in the cold-stored green pepper and zucchini squash following treatments with methyl jasmonate and superatmospheric levels of oxygen. Green pepper and zucchini squash are sensitive to chilling temperatures. However, the severity of chilling injury in these commodities was redu...

214

Upwelling around Cabo Frio, Brazil: The importance of wind stress curl  

NASA Astrophysics Data System (ADS)

Data from the SeaWinds scatterometer on the QuikSCAT satellite are used to estimate upwelling around Cabo Frio, Brazil, due to Ekman transport and Ekman pumping. The region close to shore (up to 200 km from the coast) is characterized by negative wind stress curl (upwelling favorable) year-round, with maximum values during summer, and minimum values during fall. Integrated values from São Sebastião Island to Vitória reveal that during summer, Ekman pumping and Ekman transport are of the same magnitude in the region. Estimates of Ekman transport are relatively uniform along the coast during summer. Ekman pumping, on the other hand, is strongly enhanced between São Sebastião Island and Vitória, the region where the coldest water on satellite images is frequently found. This suggests that wind stress curl-driven upwelling is a major contributor to the coldest surface water being found near Cabo Frio.

Castelao, Renato M.; Barth, John A.

2006-02-01

215

Orthogonal Helmholtz decomposition in arbitrary dimension using divergence-free and curl-free wavelets  

Microsoft Academic Search

We present tensor-product divergence-free and curl-free wavelets, and define associated projectors. These projectors enable the construction of an iterative algorithm to compute the Helmholtz decomposition of any vector field, in wavelet domain. This decomposition is localized in space, in contrast to the Helmholtz decomposition calculated by Fourier transform. Then we prove the convergence of the algorithm in dimension two for

Erwan Deriaz; Valérie Perrier

2009-01-01

216

Curling up two spatial dimensions with SU(1,1)\\/U(1)  

Microsoft Academic Search

It is seen that a nonlinear sigma model based on the noncompact coset space SU(1,1)\\/U(1) can curl up two spatial dimensions into a topologically noncompact surface of finite area with a compact U(1) isometry group. This mechanism can be used for several higher-dimensional supergravity theories. In particular, chiral N = 2, D = 10 supergravity would reduce to an N

Murray Gell-Mann; Barton Zwiebach

1984-01-01

217

An experimental investigation of Curle's theory of aerodynamic noise generation by a stationary body in a turbulent air stream  

NASA Astrophysics Data System (ADS)

Bies et al. (J. Sound Vib. 204(4) (1997) 631) investigated Curle's theory (Proc. R. Soc. Ser. A 231 (1955) 505) published in 1955 over a wide range of flow speeds from about 50-200 m/s and found only partial agreement with the experimental data. Here the experimental investigation has been repeated allowing the data to be recorded in a format amenable to analysis, which was not previously possible. Reintroduction of a term neglected by Curle has been found necessary as Curle's compact source condition ensures so low a radiation impedance that the effect cannot be detected in the jet background noise. The reintroduction of the term, which has been neglected, allows his analysis to include radiation from sources not compact but less than half a wavelength in characteristic dimension. It is shown that the power ratio defined as the measured sound power divided by Curle's amended prediction converges to about 3 whereas Curle predicts that the power ratio should converge to 1 as the wave number converges to zero. The introduction of the empirically determined constant 3 into Curle's prediction brings the measurements into very good agreement with prediction over the entire range of the non-dimensional wave numbers from about 0.4 to 3.2.

Bies, David Alan

2004-12-01

218

A novel application of Curle's acoustic analogy to aeolian tones in two dimensions  

NASA Astrophysics Data System (ADS)

A new two-dimensional formula to describe aeolian tones radiated from rigid bodies in a uniform flow at low Mach numbers is proposed as an improved approximation of Curle's dipole solution. This modified Curle's dipole is composed mainly of two simple terms; one depends on time and the other does not, which represent the acoustic propagation and the hydrodynamic mean effect, respectively. The acoustic term includes the Doppler effect by regarding the sound speed to be directional in the source-fixed frame. The formula is verified in comparison with the results by direct numerical simulations (DNS) of the two-dimensional compressible Navier-Stokes equations for sounds from a circular cylinder in low Mach number flows. The results show that the modified Curle's dipole approximates well the DNS results not only for the fluctuation pressure but also for the mean pressure in the far field. The mathematical basis of the formula is also presented in relation to the exact dipole term of the Ffowcs Williams-Hawkings equation.

Hatakeyama, Nozomu; Inoue, Osamu

2004-05-01

219

Mechanism of kaolinite sheets curling via the intercalation and delamination process.  

PubMed

Kaolinite naturally occurs in the plate form for the interlayer hydrogen bond and the distortion and adaption of tetrahedron and octahedron. But kaolinite sheets can be exfoliated to nanoscrolls artificially in laboratory through multiple-step displacement intercalation. The driving force for kaolinite sheet to be curled nanoscroll originates from the size discrepancy of Si-O tetrahedron and Al-O octahedron. The displacement intercalation promoted the platy kaolinite sheets spontaneously to be scrolled by eliminating the interlayer hydrogen bond and atomic interaction. Kaolinite nanoscrolls are hollow tubes with outer face of tetrahedral sheet and inner face of octahedral sheet. Based on the theoretical calculation it is firstly reported that the minimum interior diameter for a single kaolinite sheet to be scrolled is about 9.08nm, and the optimal 24.30nm, the maximum 100nm, which is verified by the observation of scanning electron microscope and transmission electron microscope. The different adaption types and discrepancy degree between tetrahedron and octahedron generate various curling forces in different directions. The nanoscroll axes prefer the directions as [100], [11¯0], [110], [31¯0], and the relative curling force are as follows, [31¯0]>[100]=[11¯0]>[110]. PMID:25585290

Li, Xiaoguang; Liu, Qinfu; Cheng, Hongfei; Zhang, Shuai; Frost, Ray L

2015-04-15

220

Chopping of near- and mid-infrared radiation using a curled electrostatic MEMS actuator  

NASA Astrophysics Data System (ADS)

An electrostatic MEMS actuator known as the "Artificial Eyelid" can be used as a micromechanical chopper for IR detectors. The actuator structure consists of a curled polymer/metal film stack which is microfabricated and released from an IR transparent substrate. The film stack is uncurled by applying an electric field between the curled film and the transparent fixed electrode on the substrate. These flexible film actuators can act as IR choppers, providing transmission of radiation to the sensor elements when open (curled) and reflection when closed (uncurled). Arrays of actuators were fabricated on ITO-coated glass substrates and ranged in size from 4 x 4 mm to 7.5 x 15 mm with individual elements ranging from 250 to 500 ?m on a side. Actuation for devices with average radius of curvature of 120 ? was consistently achieved at 150-170 V operation with 98-100% of the elements functioning and long lifetimes. IR chopper characteristics were measured using a blackbody source and pyroelectric detector by applying sine and square wave voltage to the actuators at a frequency of 30 Hz. The capability of the artificial eyelid for chopping near- and mid-IR radiation, including future fabrication of devices using NiCo2O4 or NiRh2O4 films for IR transparent electrodes, will be discussed.

Dausch, David E.; Goodwin, Scott H.; Exarhos, Gregory J.

2003-09-01

221

Elm Leaf Beetle  

E-print Network

Elm leaf beetles damage all varieties of elm trees. Learn how to identify this insect and understand its biology and life cycle. There are suggestions for controlling elm leaf beetles, as well as a table of insecticides effective against...

Patrick, Carl D.

2002-05-22

222

Squashed Kerr-Godel Black Holes - Kaluza-Klein Black Holes with Rotations of Black Hole and Universe -  

Microsoft Academic Search

Applying squashing transformation to Kerr-Godel black hole solutions, we\\u000apresent a new type of a rotating Kaluza-Klein black hole solution to the\\u000afive-dimensional Einstein-Maxwell theory with a Chern-Simon term. The new\\u000asolutions generated via the squashing transformation have no closed timelike\\u000acurve everywhere outside the black hole horizons. At the infinity, the metric\\u000aasymptotically approaches a twisted S^1 bundle over

Shinya Tomizawa; Hideki Ishihara; Ken Matsuno; Toshiharu Nakagawa

2008-01-01

223

COMPARATIVE SPATIAL SPREAD OVER TIME OF ZUCCHINI YELLOW MOSAIC VIRUS AND WATERMELON MOSAIC VIRUS IN FIELDS OF TRANSGENIC SQUASH EXPRESSING THE COAT PROTEIN GENES OF ZYMV AND WMV, AND IN FIELDS OF NONTRANSGENIC SQUASH  

Technology Transfer Automated Retrieval System (TEKTRAN)

The spatial and temporal patterns of aphid-vectored spread of Zucchini yellow mosaic virus (ZYMV) and Watermelon mosaic virus (WMV) were monitored over two consecutive years in plantings of nontransgenic and transgenic squash ZW-20H and ZW-20B, all surrounded by nontransgenic plants mechanically ino...

224

Improved postharvest quality in patagonian squash ( Cucurbita moschata) coated with radiation depolymerized chitosan  

NASA Astrophysics Data System (ADS)

Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes ( Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan.

Pugliese, Maria Alicia; Goitia, Maria Teresa; Yossen, Mariana; Cifone, Norma; Agulló, Enrique; Andreucetti, Noemi

2011-12-01

225

Dynamic patterns of movement of squash players of different standards in winning and losing rallies.  

PubMed

The aim of this work was to analyse and compare the dynamic motions of squash players of varying technical abilities, and link these to the tactics that the different standard players adopt. A computerized tracking system utilized mixed images on the VDU of both the tracking surface, and the subject during competitive matchplay. Four groups of squash players were categorized Elite (international); Provincial (provincial representatives); Club A/B (players at either the A or B level in the inter-club leagues in British Columbia); and Club C/D (players at the C or D level in the inter-club leagues in British Columbia). Six competitive matches of different players were analysed for each group. Each game in each match was analysed separately and means-per-rally calculated for: positional data, X and Y; lateral and longitudinal velocities, Vx and Vy; average velocities, V; distances travelled, D; and accelerations, A. The longitudinal position in the winning rallies for all groups was closer to the front wall than that in the losing rallies (p < 0.10), supporting previous research and demonstrating the operational validity of this methodology. The Elite and Provincial groups had significant differences in all the velocities and the accelerations between the winning rallies and losing rallies (p < 0.10), confirming the hypothesis that their tactic was to attempt to reduce their opponents' playing time by taking the ball as early as possible and use all of the court.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8112279

Hughes, M; Franks, I M

1994-01-01

226

Sources of Resistance in U.S. Plant Introductions to Watermelon Vine Decline Caused of Squash Vein Yellowing Virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Watermelon vine decline (WVD) caused by the whitefly-transmitted (Bemisia tabaci) Squash vein yellowing virus (SqVYV; genus Ipomovirus, family: Potyviridae) has become a major limiting factor in watermelon (Citrullus lanatus) production in southwest and west-central Florida in recent years. Sympto...

227

Squash vein yellowing virus, causal agent of viral watermelon vine decline in Florida, USA – reservoirs, genome characterization and mixed infections  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV) was identified in cucurbits in Florida in 2005, shown to be whitefly-transmissible and to induce a previously observed watermelon vine decline and fruit rind necrosis. SqVYV has been isolated from declining watermelons for the past six growing seasons in southwes...

228

CLUB DE SQUASH Hiver 2015 ACTIVIT CODE LUDIK GR HORAIRE LOCAL DBUT-FIN/DURE EM M REMARQUES  

E-print Network

Squash 0472001 01 Lu 18h30 à 21h30 00120 12 janv.-20 avr./ 14 semaines 83 108 1-2-3 02 Me 18h30 à 21h30 00120 14 janv.-15 avr./ 14 semaines 83 108 12 1. 3 tournois, 3 séances pré saison et 8 séances

229

Development and evaluation of quanitative early monitoring techniques for Squash vein yellowing virus, the cause of watermelon vine decline  

Technology Transfer Automated Retrieval System (TEKTRAN)

Watermelon vine decline caused by whitefly-transmitted Squash vein yellowing virus (SqVYV) is an emerging disease that has caused severe losses to Florida watermelon growers in recent years. Although the late stage symptoms of watermelon vine decline are basically diagnostic for the presence of SqV...

230

Transcript levels of antioxidative genes and oxygen radical scavenging enzyme activities in chilled zucchini squash in response to superatmospheric oxygen  

Technology Transfer Automated Retrieval System (TEKTRAN)

The transcript levels of antioxidative genes including Mn-superoxide dismutase (Mn-SOD), Cu/Zn SOD, ascorbate peroxidise (APX), and catalase (CAT) do not vary significantly during storage at 5 °C with high oxygen treatment in freshly harvested zucchini squash (Cucurbita pepo L. cv. Elite). However, ...

231

Squash vein yellowing virus detection using nested polymerase chain reaction demonstrates Momordica charantia is a reservoir host  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV) is a recently described ipomovirus from cucurbits in Florida that induces the relatively unusual symptoms in watermelon of plant death and fruit rind necrosis and discoloration, commonly known in Florida as watermelon vine decline. In this report, we demonstrate ...

232

The effects of ankle guards and taping on joint motion before, during, and after a squash match  

Microsoft Academic Search

The effects of ankle guards and taping on joint motion before, during, and after exercise were studied. Twelve league squash players played two matches, each last ing 1 hour. Two different ankle guards, and two types of tape applied by the same method, served as sup ports. A specially designed goniometer with electronic digital display (accuracy 1 °) was used

Kathryn H. Myburgh; Christopher L. Vaughan; Sedic K. Isaacs

1984-01-01

233

Assessing soybean leaf area and leaf biomass by spectral measurements  

NASA Technical Reports Server (NTRS)

Red and photographic infrared spectral radiances were correlated with soybean total leaf area index, green leaf area index, chlorotic leaf area index, green leaf biomass, chlorotic leaf biomass, and total biomass. The most significant correlations were found to exist between the IR/red radiance ratio data and green leaf area index and/or green leaf biomass (r squared equals 0.85 and 0.86, respectively). These findings demonstrate that remote sensing data can supply information basic to soybean canopy growth, development, and status by nondestructive determination of the green leaf area or green leaf biomass.

Holben, B. N.; Tucker, C. J.; Fan, C. J.

1979-01-01

234

A boundary element extension of Curle's analogy for non-compact geometries at low-Mach numbers  

NASA Astrophysics Data System (ADS)

The aeroacoustic analogy derived by Curle for the prediction of the sound resulting from turbulence/body interactions has proved quite powerful for low Helmholtz numbers, i.e. when the interaction region is acoustically compact. In such case, incompressible flow modeling can be used to obtain the source field used as the input of the analogy. It was, however, shown in a previous paper that Curle's analogy can yield erroneous results for non-compact cases, when an incompressible flow model is adopted. Yet, at low-Mach numbers, incompressible flow modeling can be substantially more efficient than compressible simulations, due to the stiffness issues faced by the latter. The present work focuses on the derivation of a method combining Curle's analogy with a boundary element method (BEM), in order to compensate for the weaknesses of the traditional approach at high Helmholtz numbers. The validation of this method is performed by application to a generic test case: the spinning of two vortex filaments in an infinite two-dimensional duct. This flow model is amenable to a nearly exact derivation by an incompressible vortex model. Moreover, the acoustic field can also be obtained very accurately using the tailored Green's function based on the duct modes, providing a reference solution to validate our numerical approach. The sound field predicted using the BEM/Curle approach shows excellent agreement with the reference solution based on the tailored Green's function, thereby validating the general principle of BEM/Curle method and its numerical implementation.

Schram, C.

2009-04-01

235

Leaf Pack Network  

NSDL National Science Digital Library

The Leaf Pack Network (LPN) is a network of teachers and students investigating their local stream ecosystems by participating in the leaf pack experiment, which involves creating an artificial leaf pack (dry leaves in a mesh bag), immersing it in a stream for 3-4 weeks, and examining it for signs of aquatic insects as indicators of stream health. Participating classrooms share their data through the internet. This activity highlights the connection between streamside forests and the ecology of rivers and streams.

236

Conservative management of a case of medial epicondylosis in a recreational squash player  

PubMed Central

Objective: This case study was conducted to evaluate the treatment and management of a patient presenting with medial elbow pain diagnosed as medial epicondylosis. Case: A 35 year old male presented with medial elbow pain of 4–6 weeks duration that worsened after playing squash. Treatment: A course of fascial stripping techniques was initiated, including: cross friction massage, instrument assisted fascial stripping to the medial epicondyle area and over the belly of the pronator teres muscle, ischemic compression of a trigger point in the pronator teres, active assisted compressions to the trigger point noted in the pronator teres, and mobilizations of the carpals, specifically the scaphoid. Instructions were given to the patient regarding icing the elbow and daily eccentric exercises. At a one year follow up, the patient reported complete resolution of symptoms with no recurrence. Conclusion: Conservative management, including eccentric exercises, mobilizations, and fascial stripping appear to be beneficial in the treatment of medial epicondylosis. PMID:21403779

Hudes, Karen

2011-01-01

237

A review of ipomoviruses and watermelon vine decline caused by the newly-described and whitefly-transmitted squash vein yellowing virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Though few in number, ipomoviruses cause significant disease in cucurbits and other crops in various parts of the world. As the causal agent of watermelon vine decline in Florida, Squash vein yellowing virus has recently become an economically important pathogen....

238

Leaf Hydraulics Lawren Sack1  

E-print Network

Leaf Hydraulics Lawren Sack1 and N. Michele Holbrook2 1 Department of Botany, University of Hawai influence rates of transpiration and photosynthesis. Leaf hydraulic conductance (Kleaf) varies more than 65. #12;Contents INTRODUCTION. . . . . . . . . . . . . . . . . 362 LEAF HYDRAULIC CONDUCTANCE

Sack, Lawren

239

Leaf cutter ants  

NSDL National Science Digital Library

There is much diversity between ants. Leaf cutter ants use their mandibles to cut leaf fragments and take them back to their home. They don't eat the leaves, but instead use them to grow fungus on. They then eat the fungus.

N/A N/A (None;)

2007-12-15

240

LEAF MARGIN INFLORESCENCE  

E-print Network

image. Consider submitting multiple images, each one focused ILLUSTRATION OFTHEVARIOUS PLANT PARTS USED{ LEAF BLADE LEAF MARGIN PETIOLE INFLORESCENCE WS-27-W Guidelines for Submitting Digital Plant Assistant Professor of Weed Science Purdue University The accuracy of identifying a plant from digital

Holland, Jeffrey

241

Genetic characterization of North American populations of the wheat curl mite (Aceria tosichella) and dry bulb mite (Aceria tulipae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The wheat curl mite, Aceria tosichella Keifer, transmits at least three harmful viruses, wheat streak mosaic virus (WSMV), high plains virus (HPV), and Triticum mosaic virus (TriMV) to wheat (Triticum aestivum L.) throughout the Great Plains. This virus complex is considered to be the most serious d...

242

A boundary element extension of Curle's analogy for non-compact geometries at low-Mach numbers  

Microsoft Academic Search

The aeroacoustic analogy derived by Curle for the prediction of the sound resulting from turbulence\\/body interactions has proved quite powerful for low Helmholtz numbers, i.e. when the interaction region is acoustically compact. In such case, incompressible flow modeling can be used to obtain the source field used as the input of the analogy. It was, however, shown in a previous

C. Schram

2009-01-01

243

Short communication Leaf optical properties and photosynthetic leaf absorptances  

E-print Network

Short communication Leaf optical properties and photosynthetic leaf absorptances in several-species variability in the leaf optical properties of eight large-bodied seagrasses, Posidonia australis, Posidonia of Australia. Leaf spectral transmittance [TL(l)], reflectance [RL(l)], and non-photosynthetic absorptance [AL

Durako, Michael J.

244

Global Leaf Trait Relationships: Mass, Area, and the Leaf  

E-print Network

Global Leaf Trait Relationships: Mass, Area, and the Leaf Economics Spectrum Jeanne L. D. Osnas,1,2 * Jeremy W. Lichstein,2 Peter B. Reich,3,4 Stephen W. Pacala1 The leaf economics spectrum (LES) describes multivariate correlations that constrain leaf traits of plant species primarily to a single axis of variation

Minnesota, University of

245

The geminivirus BL1 movement protein is associated with endoplasmic reticulum-derived tubules in developing phloem cells.  

PubMed Central

Plant viruses encode movement proteins that are essential for systemic infection of their host but dispensable for replication and encapsidation. BL1, one of the two movement proteins encoded by the bipartite geminivirus squash leaf curl virus, was immunolocalized to unique approximately 40-nm tubules that extended up to and across the walls of procambial cells in systemically infected pumpkin leaves. These tubules were not found in procambial cells from pumpkin seedlings inoculated with BL1 mutants that are defective in movement. The tubules also specifically stained with antisera to binding protein (BiP), indicating that they were derived from the endoplasmic reticulum. Independent confirmation of this endoplasmic reticulum association was obtained by subcellular fractionation studies in which BL1 was localized to fractions that contained both endoplasmic reticulum membranes and BiP. Thus, squash leaf curl virus appears to recruit the endoplasmic reticulum as a conduit for cell-to-cell movement of the viral genome. PMID:9094647

Ward, B M; Medville, R; Lazarowitz, S G; Turgeon, R

1997-01-01

246

A Thermistor Leaf Thermometer  

PubMed Central

An instrument is described which allows measurements of leaf temperature within about 0.3 C. It consists of a special thermistor probe, a small circuit box, and a standard ammeter. The circuit box can easily be fixed to the meter and contains a battery, which passes 0.3 milliampere through the thermistor, and also contains an integrated circuit amplifier, so that the meter reads 20 C full scale deflection, with ranges adjustable in 10 C steps. Calibration experiments show the superiority of the thermistor leaf thermometer to a thermocouple pressed onto a rubber surface with a resilience resembling that of a leaf. Images PMID:16657432

Linacre, E. T.; Harris, W. J.

1970-01-01

247

Four-Leaf Clover  

NSDL National Science Digital Library

Scientist-in-training Summer Praetorius has an unusual skillâshe is really, really good at spotting four-leaf clovers (Trifolium repens L.). A single gene causes the normally three-leafed clover to produce a fourth, supposedly lucky, leaf. As it turns out, good science depends on both close observationâa skill Praetorius uses to spot tiny shelled animals called foraminiferaâand a little bit of luck. Ari Daniel Shapiro explains. Also included is a Learn More section that provides background information on the scientists recorded in the podcast, lessons, images, and cool facts.

2009-01-01

248

Simultaneous bilateral distal biceps tendon rupture during a preacher curl exercise: a case report.  

PubMed

Complete rupture of the distal biceps tendon is a rare injury, the overwhelming majority occurring in the dominant arm of males during the fourth to sixth decades of life. Simultaneous bilateral rupture of the distal biceps tendon is an extremely rare occurrence, with only three cases reported in the literature. This unusual injury occurred in a recreational weightlifter during a preacher curl exercise. In this particular case, a 6-week delay in presentation necessitated a staged procedure in which a primary repair was feasible in one elbow, while reconstruction using allograft tissue was required in the contralateral elbow. Satisfactory results for both elbows were achieved, with return to weightlifting by one year following surgery. PMID:18333833

Rokito, Andrew S; lofin, Ilya

2008-01-01

249

The formation of wind curl in the marine atmosphere boundary layer over the East China Sea Kuroshio in spring  

NASA Astrophysics Data System (ADS)

Various data are used to investigate the characteristics of the surface wind field and rainfall on the East China Sea Kuroshio (ESK) in March and April, 2011. In March, the wind speed maximum shows over the ESK front (ESKF) in the 10 meter wind field, which agrees with the thermal wind effect. A wind curl center is generated on the warm flank of the ESKF. The winds are much weaker in April, so is the wind curl. A rainband exists over the ESKF in both the months. The Weather Research and Forecasting (WRF) model is used for further researches. The winds on the top of the marine atmosphere boundary layer (MABL) indicate that in March, a positive wind curl is generated in the whole MABL over the warm flank of the ESKF. The thermal wind effect forced by the strong SST gradient overlying the background wind leads to strong surface northeasterly winds on the ESKF, and a positive shearing vorticity is created over the warm flank of the ESKF to generate wind curl. In the smoothed sea surface temperature experiment, the presence of the ESKF is responsible for the strong northeast winds in the ESKF, and essential for the distribution of the rainfall centers in March, which confirms the mechanism above. The same simulation is made for April, 2011, and the responses from the MABL become weak. The low background wind speed weakens the effect of the thermal wind, thus no strong Ekman pumping is helpful for precipitation. There is no big difference in rainfall between the control run and the smooth SST run. Decomposition of the wind vector shows that local wind acceleration induced by the thermal wind effect along with the variations in wind direction is responsible for the pronounced wind curl/divergence over the ESKF.

Zhang, Suping; Kong, Yang

2014-12-01

250

Electronic Leaf Project  

NSDL National Science Digital Library

This article demonstrates the benefits of a direct application of technology into a science classroom by transferring a traditional activity, such as leaf identification, into an electronic format. The new dynamic medium possesses attributes that can enha

Houston, Carolyn; Hargis, Jace

2000-05-01

251

Leaf Tissue Senescence  

PubMed Central

During winter, excised leaf tissue from Rumex obtusifolius degrades chlorophyll at twice the summer rate but the plant hormones, gibberellic acid and zeatin, inhibit the senescence rate by a constant percentage, regardless of season. PMID:16659225

Manos, Peter J.; Goldthwaite, Jonathan

1975-01-01

252

Leaf to Landscape  

Microsoft Academic Search

\\u000a One fundamental “problem” for maximizing carbon gain at the leaf and higher organizational levels entails the link between\\u000a light capture and leaf energy budgets. The balance between the two processes, however, depends on the environment. For example,\\u000a shade environments limit carbon gain due to low light levels, and so we would expect plants to display traits that maximize\\u000a light interception

Stanley D. Smith; Elke Naumburg; ÜLo Niinemets; Matthew J. Germino

253

Chloroplast to Leaf  

Microsoft Academic Search

\\u000a Leaf shapes and morphologies are very diverse. Obviously there are many successful solutions to the challenge of constructing\\u000a an organ that intercepts light, enables CO2 uptake, restricts water loss, and withstands or avoids temperature extremes, herbivory, and disease. Tradeoffs exist among\\u000a capturing CO2 and light, water loss, or construction cost. So, to some extent, the various leaf structures represent different

John R. Evans; Ichiro Terashima; Yuko Hanba; Francesco Loreto

254

Leaf to Landscape  

Microsoft Academic Search

\\u000a Temporal dynamics and structural complexity of plant canopies strongly affect light harvesting, generating variable spatio-temporal\\u000a distributions of the irradiance on leaf area (Baldocchi and Collineau 1994). Leaf light interception scales linearly with\\u000a incident irradiance, but plant photosynthesis and photomorphogenesis typically exhibit a saturating response to light. Because\\u000a of the inherent nonlinearity in light responses, estimates of the photosynthetic rate at

Alessandro Cescatti; Ülo Niinemets

255

Deer predation on leaf miners via leaf abscission  

NASA Astrophysics Data System (ADS)

The evergreen oak Quercus gilva Blume sheds leaves containing mines of the leaf miner Stigmella sp. (Lepidoptera: Nepticulidae) earlier than leaves with no mines in early spring in Nara, central Japan. The eclosion rates of the leaf miner in abscised and retained leaves were compared in the laboratory to clarify the effects of leaf abscission on leaf miner survival in the absence of deer. The leaf miner eclosed successfully from both fallen leaves and leaves retained on trees. However, sika deer ( Cervus nippon centralis Kishida) feed on the fallen mined leaves. Field observations showed that deer consume many fallen leaves under Q. gilva trees, suggesting considerable mortality of leaf miners due to deer predation via leaf abscission. This is a previously unreported relationship between a leaf miner and a mammalian herbivore via leaf abscission.

Yamazaki, Kazuo; Sugiura, Shinji

2008-03-01

256

Simple method for fluorescence DNA in situ hybridization to squashed chromosomes.  

PubMed

DNA in situ hybridization (DNA ISH) is a commonly used method for mapping sequences to specific chromosome regions. This approach is particularly effective at mapping highly repetitive sequences to heterochromatic regions, where computational approaches face prohibitive challenges. Here we describe a streamlined protocol for DNA ISH that circumvents formamide washes that are standard steps in other DNA ISH protocols. Our protocol is optimized for hybridization with short single strand DNA probes that carry fluorescent dyes, which effectively mark repetitive DNA sequences within heterochromatic chromosomal regions across a number of different insect tissue types. However, applications may be extended to use with larger probes and visualization of single copy (non-repetitive) DNA sequences. We demonstrate this method by mapping several different repetitive sequences to squashed chromosomes from Drosophila melanogaster neural cells and Nasonia vitripennis spermatocytes. We show hybridization patterns for both small, commercially synthesized probes and for a larger probe for comparison. This procedure uses simple laboratory supplies and reagents, and is ideal for investigators who have little experience with performing DNA ISH. PMID:25591075

Larracuente, Amanda M; Ferree, Patrick M

2015-01-01

257

Movement of soil-applied imidacloprid and thiamethoxam into nectar and pollen of squash (Cucurbita pepo).  

PubMed

There has been recent interest in the threat to bees posed by the use of systemic insecticides. One concern is that systemic insecticides may translocate from the soil into pollen and nectar of plants, where they would be ingested by pollinators. This paper reports on the movement of two such systemic neonicotinoid insecticides, imidacloprid and thiamethoxam, into the pollen and nectar of flowers of squash (Cucurbita pepo cultivars "Multipik," "Sunray" and "Bush Delicata") when applied to soil by two methods: (1) sprayed into soil before seeding, or (2) applied through drip irrigation in a single treatment after transplant. All insecticide treatments were within labeled rates for these compounds. Pollen and nectar samples were analyzed using a standard extraction method widely used for pesticides (QuEChERS) and liquid chromatography mass spectrometric analysis. The concentrations found in nectar, 10 ± 3 ppb (mean ± s.d) for imidacloprid and 11 ± 6 ppb for thiamethoxam, are higher than concentrations of neonicotinoid insecticides in nectar of canola and sunflower grown from treated seed, and similar to those found in a recent study of neonicotinoids applied to pumpkins at transplant and through drip irrigation. The concentrations in pollen, 14 ± 8 ppb for imidacloprid and 12 ± 9 ppb for thiamethoxam, are higher than those found for seed treatments in most studies, but at the low end of the range found in the pumpkin study. Our concentrations fall into the range being investigated for sublethal effects on honey bees and bumble bees. PMID:22761727

Stoner, Kimberly A; Eitzer, Brian D

2012-01-01

258

Spontaneous and Deterministic Three-dimensional Curling of Pre-strained Elastomeric Strips: From Hemi-helix to Helix  

NASA Astrophysics Data System (ADS)

A variety of three dimensional curls are produced by a simple generic process consisting of pre-straining one elastomeric strip, joining it to another and then releasing the bi-strip. The hemi-helix, one kind of three dimensional curls, consists of multiple, alternating helical sections of half wavelength in opposite chiralities and separated by perversions. The hemi-helix wavelength and the number of perversions are determined by the strip cross-section, the constitutive behavior of the elastomer and the value of the pre-strain. Topologically, the perversions also separate regions of the helix deforming principally by bending from those where twisting dominates. Changing the prestrain and the ratio between the thickness and the width induce a phase separation of hemi-helical structure, helical structure and hybrid structure which have similarities to coiled polymer molecules and plant tendrils.

Huang, Jiangshui; Liu, Jia; Kroll, Benedikt; Bertoldi, Katia; Suo, Zhigang; Clarke, David

2012-02-01

259

LEAF-E: a tool to analyze grass leaf growth using function fitting.  

PubMed

In grasses, leaf growth is often monitored to gain insights in growth processes, biomass accumulation, regrowth after cutting, etc. To study the growth dynamics of the grass leaf, its length is measured at regular time intervals to derive the leaf elongation rate (LER) profile over time. From the LER profile, parameters such as maximal LER and leaf elongation duration (LED), which are essential for detecting inter-genotype growth differences and/or quantifying plant growth responses to changing environmental conditions, can be determined. As growth is influenced by the circadian clock and, especially in grasses, changes in environmental conditions such as temperature and evaporative demand, the LER profiles show considerable experimental variation and thus often do not follow a smooth curve. Hence it is difficult to quantify the duration and timing of growth. For these reasons, the measured data points should be fitted using a suitable mathematical function, such as the beta sigmoid function for leaf elongation. In the context of high-throughput phenotyping, we implemented the fitting of leaf growth measurements into a user-friendly Microsoft Excel-based macro, a tool called LEAF-E. LEAF-E allows to perform non-linear regression modeling of leaf length measurements suitable for robust and automated extraction of leaf growth parameters such as LER and LED from large datasets. LEAF-E is particularly useful to quantify the timing of leaf growth, which forms an important added value for detecting differences in leaf growth development. We illustrate the broad application range of LEAF-E using published and unpublished data sets of maize, Miscanthus spp. and Brachypodium distachyon, generated in independent experiments and for different purposes. In addition, we show that LEAF-E could also be used to fit datasets of other growth-related processes that follow the sigmoidal profile, such as cell length measurements along the leaf axis. Given its user-friendliness, ability to quantify duration and timing of leaf growth and broad application range, LEAF-E is a tool that could be routinely used to study growth processes following the sigmoidal profile. PMID:25435898

Voorend, Wannes; Lootens, Peter; Nelissen, Hilde; Roldán-Ruiz, Isabel; Inzé, Dirk; Muylle, Hilde

2014-01-01

260

The uptake of radionuclides by beans, squash, and corn growing in contaminated alluvial soils at Los Alamos National Laboratory.  

PubMed

Pinto beans (Phaselous vulgaris), sweet corn (Zea mays), and zucchini squash (Cucurbita pepo) were grown in a field pot study using alluvial floodplain soils contaminated with various radionuclides within Los Alamos Canyon (LAC) at Los Alamos National Laboratory, New Mexico. Soils as well as washed edible (fruit) and nonedible (stems and leaves) crop tissues were analyzed for tritium (3H), cesium (137Cs), strontium (90Sr), plutonium (238Pu and 239,240Pu), americium (241Am), and total uranium (totU). Most radionuclides, with the exception of 3H and totU, in soil and crop tissues from LAC were detected in significantly higher concentrations (p < 0.05) than in soil or crop tissues collected from regional background locations. Significant differences in radionuclide concentrations among crop species (squash were generally higher than beans or corn) and plant parts (nonedible tissue were generally higher than edible tissue) were observed. Most soil-to-plant concentration ratios for radionuclides in edible and nonedible crop tissues grown in soils from LAC were within default values in the literature commonly used in dose and risk assessment models. Overall, the maximum net positive committed effective dose equivalent (CEDE)--the CEDE plus two sigma for each radioisotope minus background and then all positive doses summed--to a hypothetical 50-year resident that ingested 352 lb ([160 kg]; the maxiumum ingestion rate per person per year) of beans, corn, and squash in equal proportions was 74 mrem y-1 (740 microS y-1). This upper bound dose was below the International Commission on Radiological Protection permissible dose limit of 100 mrem y-1 (1000 microS y-1) from all pathways and corresponds to a risk of an excess cancer fatality of 3.7 x 10(-5) (37 in a million), which is also below the U.S. Environmental Protection Agency's guideline of 10(-4). PMID:9491570

Fresquez, P R; Armstrong, D R; Mullen, M A; Naranjo, L

1998-01-01

261

Radionuclide concentrations in pinto beans, sweet corn, and zucchini squash grown in Los Alamos Canyon at Los Alamos National Laboratory  

SciTech Connect

Pinto beans, sweet corn, and zucchini squash (Cucurbita pepo var. black beauty) were grown in a randomized complete-block field/pot experiment at a site that contained the highest observed levels of surface gross gamma radioactivity within Los Alamos Canyon (LAC) at Los Alamos National Laboratory. Soils as well as washed edible and nonedible crop tissues were analyzed for various radionuclides and heavy metals . Most radionuclides, with the exception of {sup 3}H and {sup tot}U, in soil from LAC were detected in significantly higher concentrations (p <0.01) than in soil collected from regional background (RBG) locations. Similarly, most radionuclides in edible crop portions of beans, squash, and corn were detected in significantly higher (p <0.01 and 0.05) concentrations than RBG. Most soil-to-plant concentration ratios for radionuclides in edible and nonedible crop tissues from LAC were within the default values given by the Nuclear Regulatory Commission and Environmental Protection Agency. All heavy metals in soils, as well as edible and nonedible crop tissues grown in soils from LAC, were within RBG concentrations. Overall, the total maximum net positive committed effective dose equivalent (CEDE)--the CEDE plus two sigma for each radioisotope minus background and then all positive doses summed--to a hypothetical 50-year resident that ingested 160 kg of beans, corn, and squash in equal proportions, was 74 mrem y{sup -1}. This dose was below the International Commission on Radiological Protection permissible dose limit (PDL) of 100 mrem y{sup -1} from all pathways; however, the addition of other internal and external exposure route factors may increase the overall dose over the PDL. Also, the risk of an excess cancer fatality, based on 74 mrem y{sup -1}, was 3.7 x 10{sup -5} (37 in a million), which is above the Environmental Protection Agency`s (acceptable) guideline of one in a million. 31 refs., 15 tabs.

Fresquez, P.R.; Mullen, M.A.; Naranjo, L. Jr.; Armstrong, D.R.

1997-05-01

262

Complementarity in root architecture for nutrient uptake in ancient maize/bean and maize/bean/squash polycultures  

PubMed Central

Background and Aims During their domestication, maize, bean and squash evolved in polycultures grown by small-scale farmers in the Americas. Polycultures often overyield on low-fertility soils, which are a primary production constraint in low-input agriculture. We hypothesized that root architectural differences among these crops causes niche complementarity and thereby greater nutrient acquisition than corresponding monocultures. Methods A functional–structural plant model, SimRoot, was used to simulate the first 40 d of growth of these crops in monoculture and polyculture and to determine the effects of root competition on nutrient uptake and biomass production of each plant on low-nitrogen, -phosphorus and -potassium soils. Key Results Squash, the earliest domesticated crop, was most sensitive to low soil fertility, while bean, the most recently domesticated crop, was least sensitive to low soil fertility. Nitrate uptake and biomass production were up to 7 % greater in the polycultures than in the monocultures, but only when root architecture was taken into account. Enhanced nitrogen capture in polycultures was independent of nitrogen fixation by bean. Root competition had negligible effects on phosphorus or potassium uptake or biomass production. Conclusions We conclude that spatial niche differentiation caused by differences in root architecture allows polycultures to overyield when plants are competing for mobile soil resources. However, direct competition for immobile resources might be negligible in agricultural systems. Interspecies root spacing may also be too large to allow maize to benefit from root exudates of bean or squash. Above-ground competition for light, however, may have strong feedbacks on root foraging for immobile nutrients, which may increase cereal growth more than it will decrease the growth of the other crops. We note that the order of domestication of crops correlates with increasing nutrient efficiency, rather than production potential. PMID:22523423

Postma, Johannes A.; Lynch, Jonathan P.

2012-01-01

263

Living in the Leaf Litter  

NSDL National Science Digital Library

This online article, from the museum's Musings newsletter for educators, provides some mind-boggling facts about leaf litter. It has an overview of what leaf litter is and how it's produced and a link for further research.

264

The relation of wind stress curl and meridional transport in the Benguela upwelling system  

NASA Astrophysics Data System (ADS)

Spatially high resolved wind data reveals the existence of a very pronounced and persistent cyclonic (negative) wind stress curl (WSC) along the southwest African coast. Several theoretical studies have shown that negative WSC modifies the meridional currents in eastern boundary systems significantly. Since the water mass composition on the southwest African shelf is primarily controlled by the meridional currents, understanding the relation between WSC and the meridional advection is of great importance for the Benguela ecosystem. In this study, we use a regional general circulation model that is validated with observations in order to study the effect of cyclonic WSC on the meridional transport along the southwest African coast. We show that there is a connection between the meridional transport and the WSC on a seasonal time scale in the northern Benguela upwelling system (BUS). The meridional transport follows the annual and semi-annual cycles of the WSC between 20° S and 25° S. The cyclonic WSC in the northern BUS may therefore support a southward advection of tropical waters into the upwelling system.

Junker, Tim; Schmidt, Martin; Mohrholz, Volker

2015-03-01

265

Bacterial leaf spot  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial leaf spot has been reported in Australia (Queensland), Egypt, El Salvador, India, Japan, Nicaragua, Sudan, and the United States (Florida, Iowa, Kansas, Maryland, and Wisconsin). It occasionally causes locally severe defoliation and post-emergence damping-off and stunting. The disease is...

266

Science Nation: Leaf Sensor  

NSDL National Science Digital Library

Who might know more about what a plant needs than a farmer or a greenhouse owner? How about the plant itself? What if plants could tell us when they are thirsty? With funding from the National Science Foundation (NSF), AgriHouse has developed a leaf sensor that is enabling plants to do just that.

267

Curl flux, coherence, and population landscape of molecular systems: nonequilibrium quantum steady state, energy (charge) transport, and thermodynamics.  

PubMed

We established a theoretical framework in terms of the curl flux, population landscape, and coherence for non-equilibrium quantum systems at steady state, through exploring the energy and charge transport in molecular processes. The curl quantum flux plays the key role in determining transport properties and the system reaches equilibrium when flux vanishes. The novel curl quantum flux reflects the degree of non-equilibriumness and the time-irreversibility. We found an analytical expression for the quantum flux and its relationship to the environmental pumping (non-equilibriumness quantified by the voltage away from the equilibrium) and the quantum tunneling. Furthermore, we investigated another quantum signature, the coherence, quantitatively measured by the non-zero off diagonal element of the density matrix. Populations of states give the probabilities of individual states and therefore quantify the population landscape. Both curl flux and coherence depend on steady state population landscape. Besides the environment-assistance which can give dramatic enhancement of coherence and quantum flux with high voltage at a fixed tunneling strength, the quantum flux is promoted by the coherence in the regime of small tunneling while reduced by the coherence in the regime of large tunneling, due to the non-monotonic relationship between the coherence and tunneling. This is in contrast to the previously found linear relationship. For the systems coupled to bosonic (photonic and phononic) reservoirs the flux is significantly promoted at large voltage while for fermionic (electronic) reservoirs the flux reaches a saturation after a significant enhancement at large voltage due to the Pauli exclusion principle. In view of the system as a quantum heat engine, we studied the non-equilibrium thermodynamics and established the analytical connections of curl quantum flux to the transport quantities such as energy (charge) transfer efficiency, chemical reaction efficiency, energy dissipation, heat and electric currents observed in the experiments. We observed a perfect transfer efficiency in chemical reactions at high voltage (chemical potential difference). Our theoretical predicted behavior of the electric current with respect to the voltage is in good agreements with the recent experiments on electron transfer in single molecules. PMID:24985680

Zhang, Z D; Wang, J

2014-06-28

268

LEAF GUI: User Manual (Leaf Extraction and Analysis Framework Graphical User Interface)  

E-print Network

LEAF GUI: User Manual (Leaf Extraction and Analysis Framework Graphical User Interface) #12;LEAF GUI User Manual Price et al. Index How to cite the LEAF GUI......................................................................................................................Page 28 2 #12;LEAF GUI User Manual Price et al. How to cite the LEAF GUI The LEAF GUI

Weitz, Joshua S.

269

Evaluation of the potential of squash pumpkin by-products (seeds and shell) as sources of antioxidant and bioactive compounds.  

PubMed

The transformation of byproducts and wastes generated by agro-food companies is of high importance since only a small portion of plant material is utilized directly for human consumption. Squash pumpkin is greatly used in Portugal and as by-products of its processing are generated tons of shell and seeds. In this study we aim to evaluate the potential of these wastes as sources of beneficial and bioactive compounds (antioxidants and antimicrobials), studying the effect of different extraction solvents and drying methods. The samples (fresh and cooked) were freeze-dried and oven-dried followed by extraction with different solvents that revealed the following decreasing order of efficiency: 70 % ethanol, 70 % methanol, 70 % acetone, ultra-pure water and 100 % dichloromethane. The oven-dried samples showed higher values of antioxidant activity and phenolic content, with exception of the values of phenolics for the seeds material. The shell samples presented higher values (1.47 - 70.96 % inhibition) of antioxidant activity and total phenolic content (2.00 - 10.69 mg GAE/g DW). A positive correlation was found between these two parameters on the shell samples, however the squash seeds revealed a negative correlation between the phenolic content and the antioxidant activity. The results show that these industrial agro-food residues are potentially good sources of bioactive compounds with health benefits. PMID:25694712

Saavedra, M J; Aires, A; Dias, C; Almeida, J A; De Vasconcelos, M C B M; Santos, P; Rosa, E A

2015-02-01

270

The cultural and chronological context of early Holocene maize and squash domestication in the Central Balsas River Valley, Mexico  

PubMed Central

Molecular evidence indicates that the wild ancestor of maize is presently native to the seasonally dry tropical forest of the Central Balsas watershed in southwestern Mexico. We report here on archaeological investigations in a region of the Central Balsas located near the Iguala Valley in Guerrero state that show for the first time a long sequence of human occupation and plant exploitation reaching back to the early Holocene. One of the sites excavated, the Xihuatoxtla Shelter, contains well-stratified deposits and a stone tool assemblage of bifacially flaked points, simple flake tools, and numerous handstones and milling stone bases radiocarbon dated to at least 8700 calendrical years B.P. As reported in a companion paper (Piperno DR, et al., in this issue of PNAS), starch grain and phytolith residues from the ground and chipped stone tools, plus phytoliths from directly associated sediments, provide evidence for maize (Zea mays L.) and domesticated squash (Cucurbita spp.) in contexts contemporaneous with and stratigraphically below the 8700 calendrical years B.P. date. The radiocarbon determinations, stratigraphic integrity of Xihuatoxtla's deposits, and characteristics of the stone tool assemblages associated with the maize and squash remains all indicate that these plants were early Holocene domesticates. Early agriculture in this region of Mexico appears to have involved small groups of cultivators who were shifting their settlements seasonally and engaging in a variety of subsistence pursuits. PMID:19307573

Ranere, Anthony J.; Piperno, Dolores R.; Holst, Irene; Dickau, Ruth; Iriarte, José

2009-01-01

271

Scolicidal effects of squash (Corylus spp) seeds, hazel (Curcurbia spp) nut and garlic (Allium sativum) extracts on hydatid cyst protoscolices  

PubMed Central

Background: Because there is no effective drug therapy for hydatid cyst yet, assessment and finding of some new agents especially from herbal origin with a desired scolicidal effect attracts great attention for treatment and pre-surgical use to prevent the hydatid cyst recurrence. Hazelnut, squash seeds and garlic chloroformic and hydro-alcoholic extracts’ scolicidal effects were examined. Materials and Methods: Suspension of protoscolices was obtained from infected liver and or lung of sheep and goats from Ziyaran abattoir. The chloroformic and hydro-alcoholic extracts from hazelnut, squash seeds and garlic were extracted using the succilate method. Scolicidal effect of each extract assessed in different concentrations and effected time using microscopy and 0.1% eosin solution stained only killed protoscolices. Results: Present study showed that garlic had more potent scolicidal effects among all the 3 plants and the chloroformic extract of garlic was the most potent protoscolicid among all of the extracts and killed 98% of protoscolices in 50 mg/ml on a minimum of 20 minutes exposure. Conclusion: Garlic chloroformic extract is a safe and potent protoscolicid and might be used in hydatid cyst treatment and pre-surgery to prevent secondary cyst recurrence. PMID:23833573

Eskandarian, Abbas Ali

2012-01-01

272

Genetic characterization of North American populations of the wheat curl mite and dry bulb mite.  

PubMed

The wheat curl mite, Aceria tosichella Keifer, transmits at least three harmful viruses, wheat streak mosaic virus (WSMV), high plains virus (HPV), and Triticum mosaic virus (TriMV) to wheat (Triticum aestivum L.) throughout the Great Plains. This virus complex is considered to be the most serious disease of winter wheat in the western Great Plains. One component of managing this disease has been developing mite resistance in wheat; however, identification of mite biotypes has complicated deployment and stability of resistance. This biotypic variability in mites and differential virus transmission by different mite populations underscores the need to better understand mite identity. However, A. tosichella has a history of serious taxonomic confusion, especially as it relates to A. tulipae Keifer, the dry bulb mite. Molecular techniques were used to genetically characterize multiple A. tosichella populations and compare them to populations of A. tulipae. DNA from these populations was polymerase chain reaction amplified and the ribosomal ITS2 region sequenced and compared. These results indicated limited variability between these two species, but two distinct types within A. tosichella were found that corresponded to previous work with Australian mite populations. Further work using sequencing of several mitochondrial DNA genes also demonstrated two distinct types of A. tosichella populations. Furthermore, the separation between these two A. tosichella types is comparable to their separation with A. tulipae, suggesting that species scale differences exist between these two types ofA. tosichella. These genetic differences correspond to important biological differences between the types (e.g., biotypic and virus transmission differences). In light of these differences, it is important that future studies on biological response differences account for these mite differences. PMID:23156180

Hein, Gary L; French, Roy; Siriwetwiwat, Benjawan; Amrine, James W

2012-10-01

273

Wheat curl mite, Aceria tosichella, and transmitted viruses: an expanding pest complex affecting cereal crops.  

PubMed

The wheat curl mite (WCM), Aceria tosichella, and the plant viruses it transmits represent an invasive mite-virus complex that has affected cereal crops worldwide. The main damage caused by WCM comes from its ability to transmit and spread multiple damaging viruses to cereal crops, with Wheat streak mosaic virus (WSMV) and Wheat mosaic virus (WMoV) being the most important. Although WCM and transmitted viruses have been of concern to cereal growers and researchers for at least six decades, they continue to represent a challenge. In older affected areas, for example in North America, this mite-virus complex still has significant economic impact. In Australia and South America, where this problem has only emerged in the last decade, it represents a new threat to winter cereal production. The difficulties encountered in making progress towards managing WCM and its transmitted viruses stem from the complexity of the pathosystem. The most effective methods for minimizing losses from WCM transmitted viruses in cereal crops have previously focused on cultural and plant resistance methods. This paper brings together information on biological and ecological aspects of WCM, including its taxonomic status, occurrence, host plant range, damage symptoms and economic impact. Information about the main viruses transmitted by WCM is also included and the epidemiological relationships involved in this vectored complex of viruses are also addressed. Management strategies that have been directed at this mite-virus complex are presented, including plant resistance, its history, difficulties and advances. Current research perspectives to address this invasive mite-virus complex and minimize cereal crop losses worldwide are also discussed. PMID:23179064

Navia, Denise; de Mendonça, Renata Santos; Skoracka, Anna; Szyd?o, Wiktoria; Knihinicki, Danuta; Hein, Gary L; da Silva Pereira, Paulo Roberto Valle; Truol, Graciela; Lau, Douglas

2013-02-01

274

Identification of plant reservoirs and genome characterization of Squash vein yellowing virus, causal agent of viral watermelon vine decline in Florida  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV) was identified in cucurbits in Florida in 2005 and shown to be whitefly-transmissible and to induce a previously observed watermelon vine decline and fruit rind necrosis. Only cucurbits have been determined to be hosts for SqVYV so common cucurbit weeds in south ...

275

Presence of P1b and absence of HC-Pro in Squash vein yellowing virus suggests a general feature of the genus Ipomovirus in the family Potyviridae  

Technology Transfer Automated Retrieval System (TEKTRAN)

The genus Ipomovirus is one of six currently recognized genera in the family Potyviridae. The complete nucleotide sequence of Squash vein yellowing virus (SqVYV), a putative ipomovirus recently described in Florida, has been determined. The SqVYV genomic RNA has one large open reading frame encoding...

276

Use of latent class analysis to estimate the sensitivities and specificities of diagnostic tests for Squash vein yellowing virus in cucurbits  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV) causes watermelon vine decline in watermelon (Citrullus lanatus var. lanatus). Current methods for identification of SqVYV-infected plants are based on the polymerase chain reaction (RT-PCR), tissue blot nucleic acid hybridization assays (NAHA), and visual symptom...

277

Identification of immune system gene silencing targets in a de novo assembly of the transcriptome of the squash bug, Anasa tristis (De Geer) (Heteroptera: coreidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Squash bug is a major piercing/sucking pest of cucurbits causing extensive damage to plants and fruits, and transmitting phytopathogens. There are few effective biological control agents or cultural practices for controlling this highly destructive pest. A promising new approach for control is...

278

Effects of cooking on the cell walls (dietary fiber) of 'Scarlet Warren' winter squash ( Cucurbita maxima ) studied by polysaccharide linkage analysis and solid-state (13)C NMR.  

PubMed

Cell wall polysaccharides of 'Scarlet Warren' winter squash ( Cucurbita maxima ) were investigated before and after thermal processing. Linkage analysis of polysaccharides was done by gas chromatography coupled to mass spectrometry (GC-MS). The linkage analysis showed the cell wall polysaccharide compositions of raw and cooked squash were similar. The total pectic polysaccharides (galacturonan, rhamnogalacturonan, arabinan, and arabinogalactan) contents of the cell walls of both raw and cooked squash were 39 mol %. The amounts of pectic polysaccharides and xyloglucan in the cell walls of squash showed little alteration on heating. The cellulose content of the raw and cooked cell walls was relatively high at 47 mol %, whereas the xyloglucan content was low at 4 mol %. Solid-state (13)C nuclear magnetic resonance (NMR) spectroscopy techniques were used to examine the molecular motion of the polysaccharides in the cell walls. The mobility of highly flexible galactan depends on the water content of the sample, but no difference was seen between raw and cooked samples. Likewise, the mobility of semimobile pectic polysaccharides was apparently unaltered by cooking. No change was detected in the rigid cellulose microfibrils on cooking. PMID:21604813

Ratnayake, R M Sunil; Sims, Ian M; Newman, Roger H; Melton, Laurence D

2011-07-13

279

Leaf absorbance and photosynthesis  

NASA Technical Reports Server (NTRS)

The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

Schurer, Kees

1994-01-01

280

Radiative characteristics of plant leaf  

Microsoft Academic Search

Existing leaf radiation models are reviewed. A new concept of the optical model of the leaf as a multiphase system containing\\u000a three aggregate ensembles of particles significantly different in microphysical and optical characteristics is proposed. The\\u000a proposed model is based on the reconstruction of the particle size distribution function from the experimental leaf absorption\\u000a spectrum. Based on the obtained microphysical

G. M. Krekov; M. M. Krekova; A. A. Lisenko; A. Ya. Sukhanov

2009-01-01

281

Hydraulic conductance and water potential gradients in squash leaves showing mycorrhiza-induced increases in stomatal conductance  

Microsoft Academic Search

Stomatal conductance (g\\u000a s) and transpiration rates vary widely across plant species. Leaf hydraulic conductance (k\\u000a leaf) tends to change with g\\u000a s, to maintain hydraulic homeostasis and prevent wide and potentially harmful fluctuations in transpiration-induced water potential\\u000a gradients across the leaf (??\\u000a leaf). Because arbuscular mycorrhizal (AM) symbiosis often increases g\\u000a s in the plant host, we tested whether

Robert M. Augé; Heather D. Toler; Carl E. Sams; Ghazala Nasim

2008-01-01

282

Combining Leaf Salient Points and Leaf Contour Descriptions for Plant Species Recognition  

E-print Network

Combining Leaf Salient Points and Leaf Contour Descriptions for Plant Species Recognition Sofiene for plant species recognition, based on the leaf observation. We consider two sources of information: the leaf margin and the leaf salient points. For the leaf shape description, we investigate the shape

Verroust-Blondet, Anne

283

Seasonal changes in leaf area of Amazon forests from leaf flushing and abscission  

E-print Network

Seasonal changes in leaf area of Amazon forests from leaf flushing and abscission Arindam Samanta,1 as seasonal change in leaf area resulting from net leaf flushing in the dry season or net leaf abscission and as change in leaf scattering and absorption properties between younger and older leaves covered

Goldberg, Bennett

284

Estimating Corn Leaf Chlorophyll Concentration from Leaf and Canopy Reflectance  

Microsoft Academic Search

Farmers must balance the competing goals of supplying adequate N for their crops while minimizing N losses to the environment. To characterize the spatial variability of N over large fields, traditional methods (soil testing, plant tissue analysis, and chlorophyll meters) require many point samples. Because of the close link between leaf chlorophyll and leaf N concentration, remote sensing techniques have

C. S. T. Daughtry; C. L. Walthall; M. S. Kim; E. Brown de Colstoun; J. E. McMurtrey III

2000-01-01

285

The regulatory light chain of nonmuscle myosin is encoded by spaghetti-squash, a gene required for cytokinesis in Drosophila.  

PubMed

Two independent approaches to understanding the molecular mechanism of cytokinesis have converged on the gene spaghetti-squash (sqh). A genetic screen for mitotic mutants identified sqh1, a mutation that disrupts cytokinesis, which was then cloned by transposon tagging. Independently, the gene that encodes the regulatory light chain of the biochemically defined nonmuscle myosin (MRLC-C) was also cloned. We show here that sqh encodes MRLC-C and that in sqh1 mutants, the level of stable light chain transcript is greatly reduced. Reversion by transposon excision or transformation with a wild-type copy of the sqh transcription unit rescues cytokinesis failure and other defects in sqh1. Vertebrate homologs of MRLC-C are phosphorylatable and regulate myosin activity in vitro. These studies provide genetic proof that MRLC-C is required for cytokinesis, suggest a role for the protein in regulating contractile ring function, and establish a genetic system to evaluate its function. PMID:1905980

Karess, R E; Chang, X J; Edwards, K A; Kulkarni, S; Aguilera, I; Kiehart, D P

1991-06-28

286

The presence of tomato leaf curl Kerala virus AC3 protein enhances viral DNA replication and modulates virus induced gene-silencing mechanism in tomato plants  

PubMed Central

Background Geminiviruses encode few viral proteins. Most of the geminiviral proteins are multifunctional and influence various host cellular processes for the successful viral infection. Though few viral proteins like AC1 and AC2 are well characterized for their multiple functions, role of AC3 in the successful viral infection has not been investigated in detail. Results We performed phage display analysis with the purified recombinant AC3 protein with Maltose Binding Protein as fusion tag (MBP-AC3). Putative AC3 interacting peptides identified through phage display were observed to be homologous to peptides of proteins from various metabolisms. We grouped these putative AC3 interacting peptides according to the known metabolic function of the homologous peptide containing proteins. In order to check if AC3 influences any of these particular metabolic pathways, we designed vectors for assaying DNA replication and virus induced gene-silencing of host gene PCNA. Investigation with these vectors indicated that AC3 enhances viral replication in the host plant tomato. In the PCNA gene-silencing experiment, we observed that the presence of functional AC3 ORF strongly manifested the stunted phenotype associated with the virus induced gene-silencing of PCNA in tomato plants. Conclusions Through the phage display analysis proteins from various metabolic pathways were identified as putative AC3 interacting proteins. By utilizing the vectors developed, we could analyze the role of AC3 in viral DNA replication and host gene-silencing. Our studies indicate that AC3 is also a multifunctional protein. PMID:21496351

2011-01-01

287

A review of the mechanisms and components that determine the transmission efficiency of Tomato yellow leaf curl virus (Geminiviridae; Begomovirus) by its whitefly vector.  

PubMed

Begomoviruses are a group of icosahedral single stranded DNA viruses exclusively transmitted by the sweet potato whitefly Bemisia tabaci in a persistent, circulative manner. In this mode of transmission, begomoviruses are acquired by their insect vector as intact virions from the plant phloem, move along the food canal, foregut and esophagus and reach the midgut where they are absorbed into the hemolymph via the filter chamber. The filter chamber is the site where most of the ingested food is filtered, and the first site where the majority of begomoviruses appear to be translocated into the hemolymph via unknown proteins or receptors. Transport from the filter chamber to the hemolymph is aided by a Heat Shock Protein 70. Virus particles not translocated across the filter chamber circulate in the midgut loop but it is not known whether absorption into the hemolymph occurs along this loop. Localization studies have confirmed that begomoviruses are not associated with the hindgut and absorption of virions in this organ is unlikely. In the hemolymph, virions have been shown to interact with a GroEL chaperone produced by the whitefly's endosymbiontic bacteria for ensuring their safe journey to the salivary glands. Virions penetrate the primary salivary glands via unknown proteins or receptors and are transported and secreted outside the whitefly to the plant with salivary secretions. Several recent studies have demonstrated the implications of insect and endosymbiont proteins such as the heat shock protein 70 and the bacterial GroEL protein, in the transmission of begomoviruses by B. tabaci. Additional studies attempting to identify other proteins that aid or interact with begomoviruses along their circulation pathway in the whitefly are reviewed in this paper. PMID:24508344

Ghanim, Murad

2014-06-24

288

Trapping of Tomato yellow leaf curl virus (TYLCV) and other plant viruses with a GroEL homologue from the whitefly Bemisia tabaci  

Microsoft Academic Search

Summary. To avoid destruction in the haemolymph of their vector, many plant circulative viruses interact with GroEL homologues produced by insect endosymbiotic bacteria. We have exploited this phenomenon to devise tools allowing trapping of plant viruses by either GroEL purified from the whitefly Bemisia tabaci or by whitefly GroEL over-expressed in E. coli. PCR tubes or 96-well plates coated with

F. Akad; N. Dotan; H. Czosnek

2004-01-01

289

Variability of sea surface temperature in the Japan Sea and its relationship to the wind-curl field  

NASA Astrophysics Data System (ADS)

The variability of sea surface temperature (SST) in the Japan Sea is investigated using the complex EOF analysis of daily data produced at Tohoku University, Japan (New Generation SST; 2002-2006). The relationship with the wind field is investigated from the daily NCEP/NCAR reanalysis data with a 1° spatial resolution. Anomalies in the SST (SSTAs) are calculated by subtracting the basin-average annual variation estimated as a leading mode of temperature. The leading mode of an SSTA represents a adjustment to the annual mean variation, most significant in December in the zone of subtropical waters entering the sea through the Korean Strait and in the northwestern sea, over which a cyclonic wind curl develops in the cold period. The semiannual variability mode is identified, which is characterized by the largest temperature increase (decrease) in the western branch of the subarctic front (in the Tatar Strait), which lags by two months behind the semiannual changes in wind curl over the sea. An episodic SSTA movement is detected in the northern part of the sea, which moves from east to west along the western branch of the Tsushima Warm Current with a speed corresponding in magnitude to an advective scale.

Trusenkova, O. O.; Lobanov, V. B.; Kaplunenko, D. D.

2008-08-01

290

7 CFR 29.6023 - Leaf structure.  

Code of Federal Regulations, 2011 CFR

...2 2011-01-01 2011-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture ...INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its...

2011-01-01

291

7 CFR 29.6023 - Leaf structure.  

Code of Federal Regulations, 2010 CFR

...2 2010-01-01 2010-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture ...INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its...

2010-01-01

292

7 CFR 29.6023 - Leaf structure.  

Code of Federal Regulations, 2013 CFR

...2 2013-01-01 2013-01-01 false Leaf structure. 29.6023 Section 29.6023...INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its porosity. The degrees...

2013-01-01

293

7 CFR 29.6022 - Leaf scrap.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture...INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2013-01-01

294

7 CFR 29.6023 - Leaf structure.  

Code of Federal Regulations, 2014 CFR

...2 2014-01-01 2014-01-01 false Leaf structure. 29.6023 Section 29.6023...INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its porosity. The degrees...

2014-01-01

295

7 CFR 29.6022 - Leaf scrap.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture...INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2014-01-01

296

7 CFR 29.2529 - Leaf scrap.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture...23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2010-01-01

297

7 CFR 29.6022 - Leaf scrap.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture...INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2012-01-01

298

7 CFR 29.6022 - Leaf scrap.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture...INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2010-01-01

299

7 CFR 29.2529 - Leaf scrap.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture...23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2013-01-01

300

7 CFR 29.6023 - Leaf structure.  

Code of Federal Regulations, 2012 CFR

...2 2012-01-01 2012-01-01 false Leaf structure. 29.6023 Section 29.6023...INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its porosity. The degrees...

2012-01-01

301

7 CFR 29.2529 - Leaf scrap.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture...23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2012-01-01

302

7 CFR 29.2529 - Leaf scrap.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf scrap. 29.2529 Section 29.2529 Agriculture...23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2014-01-01

303

7 CFR 29.6022 - Leaf scrap.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture...INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2011-01-01

304

The artificial leaf.  

PubMed

To convert the energy of sunlight into chemical energy, the leaf splits water via the photosynthetic process to produce molecular oxygen and hydrogen, which is in a form of separated protons and electrons. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into spatially separated electron-hole pairs. The holes of this wireless current are captured by the oxygen evolving complex (OEC) of photosystem II (PSII) to oxidize water to oxygen. The electrons and protons produced as a byproduct of the OEC reaction are captured by ferrodoxin of photosystem I. With the aid of ferrodoxin-NADP(+) reductase, they are used to produce hydrogen in the form of NADPH. For a synthetic material to realize the solar energy conversion function of the leaf, the light-absorbing material must capture a solar photon to generate a wireless current that is harnessed by catalysts, which drive the four electron/hole fuel-forming water-splitting reaction under benign conditions and under 1 sun (100 mW/cm(2)) illumination. This Account describes the construction of an artificial leaf comprising earth-abundant elements by interfacing a triple junction, amorphous silicon photovoltaic with hydrogen- and oxygen-evolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate cluster (Co-OEC), respectively. The latter captures the structural and functional attributes of the PSII-OEC. Similar to the PSII-OEC, the Co-OEC self-assembles upon oxidation of an earth-abundant metal ion from 2+ to 3+, may operate in natural water at room temperature, and is self-healing. The Co-OEC also activates H(2)O by a proton-coupled electron transfer mechanism in which the Co-OEC is increased by four hole equivalents akin to the S-state pumping of the Kok cycle of PSII. X-ray absorption spectroscopy studies have established that the Co-OEC is a structural relative of Mn(3)CaO(4)-Mn cubane of the PSII-OEC, where Co replaces Mn and the cubane is extended in a corner-sharing, head-to-tail dimer. The ability to perform the oxygen-evolving reaction in water at neutral or near-neutral conditions has several consequences for the construction of the artificial leaf. The NiMoZn alloy may be used in place of Pt to generate hydrogen. To stabilize silicon in water, its surface is coated with a conducting metal oxide onto which the Co-OEC may be deposited. The net result is that immersing a triple-junction Si wafer coated with NiMoZn and Co-OEC in water and holding it up to sunlight can effect direct solar energy conversion via water splitting. By constructing a simple, stand-alone device composed of earth-abundant materials, the artificial leaf provides a means for an inexpensive and highly distributed solar-to-fuels system that employs low-cost systems engineering and manufacturing. Through this type of system, solar energy can become a viable energy supply to those in the non-legacy world. PMID:22475039

Nocera, Daniel G

2012-05-15

305

The worldwide leaf economics spectrum  

Microsoft Academic Search

Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional

Ian J. Wright; Peter B. Reich; Mark Westoby; David D. Ackerly; Zdravko Baruch; Frans Bongers; Jeannine Cavender-Bares; Terry Chapin; Johannes H. C. Cornelissen; Matthias Diemer; Jaume Flexas; Eric Garnier; Philip K. Groom; Javier Gulias; Kouki Hikosaka; Byron B. Lamont; Tali Lee; William Lee; Christopher Lusk; Jeremy J. Midgley; Marie-Laure Navas; Ülo Niinemets; Jacek Oleksyn; Noriyuki Osada; Pieter Poot; Lynda Prior; Vladimir I. Pyankov; Catherine Roumet; Sean C. Thomas; Mark G. Tjoelker; Erik J. Veneklaas; Rafael Villar

2004-01-01

306

Exserohilum Leaf Spot on Tigergrass  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tigergrass (Thysanolaena maxima (Roxb.) Kuntze ) is a popular ornamental grass grown throughout landscapes in South Florida. In the summer of 2006, a leaf spot was observed on tigergrass in the landscape and a commercial nursery in Homestead, FL. The causal agent of the leaf spot was isolated, cha...

307

The basis for variation in leaf longevity of plants  

Microsoft Academic Search

Any theory of leaf phenology must predict leaf longevity, leaf habit, leaf expansion and its timing among other variables. These phenological traits may be important keys to understand the response of trees to climatic change. Here I concentrate on and review two of these critical phenological traits, leaf longevity and leaf habit. Theories of leaf longevity were re-evaluated and leaf

Kihachiro Kikuzawa

1995-01-01

308

Giardia Cyst Wall Protein 1 Is a Lectin That Binds to Curled Fibrils of the GalNAc Homopolymer  

PubMed Central

The infectious and diagnostic stage of Giardia lamblia (also known as G. intestinalis or G. duodenalis) is the cyst. The Giardia cyst wall contains fibrils of a unique ?-1,3-linked N-acetylgalactosamine (GalNAc) homopolymer and at least three cyst wall proteins (CWPs) composed of Leu-rich repeats (CWPLRR) and a C-terminal conserved Cys-rich region (CWPCRR). Our goals were to dissect the structure of the cyst wall and determine how it is disrupted during excystation. The intact Giardia cyst wall is thin (?400 nm), easily fractured by sonication, and impermeable to small molecules. Curled fibrils of the GalNAc homopolymer are restricted to a narrow plane and are coated with linear arrays of oval-shaped protein complex. In contrast, cyst walls of Giardia treated with hot alkali to deproteinate fibrils of the GalNAc homopolymer are thick (?1.2 µm), resistant to sonication, and permeable. The deproteinated GalNAc homopolymer, which forms a loose lattice of curled fibrils, is bound by native CWP1 and CWP2, as well as by maltose-binding protein (MBP)-fusions containing the full-length CWP1 or CWP1LRR. In contrast, neither MBP alone nor MBP fused to CWP1CRR bind to the GalNAc homopolymer. Recombinant CWP1 binds to the GalNAc homopolymer within secretory vesicles of Giardia encysting in vitro. Fibrils of the GalNAc homopolymer are exposed during excystation or by treatment of heat-killed cysts with chymotrypsin, while deproteinated fibrils of the GalNAc homopolymer are degraded by extracts of Giardia cysts but not trophozoites. These results show the Leu-rich repeat domain of CWP1 is a lectin that binds to curled fibrils of the GalNAc homopolymer. During excystation, host and Giardia proteases appear to degrade bound CWPs, exposing fibrils of the GalNAc homopolymer that are digested by a stage-specific glycohydrolase. PMID:20808847

Chatterjee, Aparajita; Carpentieri, Andrea; Ratner, Daniel M.; Bullitt, Esther; Costello, Catherine E.; Robbins, Phillips W.; Samuelson, John

2010-01-01

309

Wheat curl mite, a global pest of cereals, is a complex of biotypes with divergent host ranges and variable pest potential  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background. The wheat curl mite (Aceria tosichella) is a global pest of wheat and other cereals, causing losses by direct damage as well as transmission of plant pathogens such as wheat streak mosaic virus. This mite has long been considered to be a single, highly polyphagous species, capable of co...

310

Substitution of conserved cysteine residues in Wheat streak mosaic virus HC-Pro abolishes virus transmission by the wheat curl mite  

Technology Transfer Automated Retrieval System (TEKTRAN)

Substitutions in the amino-terminal region of Wheat streak mosaic virus (WSMV) HC-Pro were evaluated for effects on transmission by the wheat curl mite (Aceria tosichella Keifer). Alanine substitution at cysteine residues 16, 46 and 49 abolished vector transmission. Although alanine substitution a...

311

Amino acid substitutions of cysteine residues near the amino terminus of Wheat streak mosaic virus HC-Pro abolishes virus transmission by the wheat curl mite  

Technology Transfer Automated Retrieval System (TEKTRAN)

The amino-terminal half of HC-Pro of Wheat streak mosaic virus (WSMV) is required for semi-persistent transmission by the wheat curl mite (Aceria tosichella Keifer). The amino-proximal region of WSMV HC-Pro is cysteine-rich with a zinc finger-like motif. Amino acid substitutions were made in this re...

312

Healing the Wounds of War and More: An Integrative Approach to Peace--The Work of Adam Curle and Others with Mir i dobro in Zupanja, Croatia.  

ERIC Educational Resources Information Center

Examines practical implications of Curle's approach to psychological aspects of conflict and peacemaking as evidenced in the Mir i dobro project in Zupanja, taking into consideration some of the current debates concerning treatment of psychological trauma, including validity of the diagnosis of posttraumatic stress disorder and use of so-called…

Mitchels, Barbara

2003-01-01

313

Leaf hydraulics II: vascularized tissues.  

PubMed

Current models of leaf hydration employ an Ohm's law analogy of the leaf as an ideal capacitor, neglecting the resistance to flow between cells, or treat the leaf as a plane sheet with a source of water at fixed potential filling the mid-plane, neglecting the discrete placement of veins as well as their resistance. We develop a model of leaf hydration that considers the average conductance of the vascular network to a representative areole (region bounded by the vascular network), and represent the volume of tissue within the areole as a poroelastic composite of cells and air spaces. Solutions to the 3D flow problem are found by numerical simulation, and these results are then compared to 1D models with exact solutions for a range of leaf geometries, based on a survey of temperate woody plants. We then show that the hydration times given by these solutions are well approximated by a sum of the ideal capacitor and plane sheet times, representing the time for transport through the vasculature and tissue respectively. We then develop scaling factors relating this approximate solution to the 3D model, and examine the dependence of these scaling factors on leaf geometry. Finally, we apply a similar strategy to reduce the dimensions of the steady state problem, in the context of peristomatal transpiration, and consider the relation of transpirational gradients to equilibrium leaf water potential measurements. PMID:24012489

Rockwell, Fulton E; Holbrook, N Michele; Stroock, Abraham D

2014-01-01

314

Soaking Summer Squash Seeds in Low Concentrations of Cobalt Solution Before Sowing Increased Plant Growth, Femaleness, and Fruit Yield via Increasing Plant Ethylene Level  

Microsoft Academic Search

.   Soaking summer squash (Cucurbita pepo cv. Eskandarany) seeds in continuously aerated solutions of 0.25, 0.50, and 1.00 ppm Co2+ for 48 h before sowing strongly increased plant growth, femaleness, and fruit yield compared with those of water- (control)\\u000a or 0.5 mm AOA (aminooxyacetic acid)-soaked seeds. Following the same pattern, plants of Co2+-soaked seeds produced significantly higher ethylene levels as

M. A. Atta-Aly

1998-01-01

315

Molecular markers indicate that the wheat curl mite, Aceria tosichella Keifer, may represent a species complex in Australia.  

PubMed

The wheat curl mite (WCM), Aceria tosichella Keifer, is an eriophyoid pest of cereals, and the vector responsible for transmitting wheat streak mosaic virus. Several authors have suggested cryptic species of this mite identified through morphological variation, but this has never been conclusively demonstrated. Here, we use the mitochondrial 16S rRNA gene and two nuclear markers (internal transcribed spacer 1 and adenine nucleotide translocase) to show that WCM from Australia consists of at least two separate lineages that may represent putative species. In our study, both WCM variants were widespread and the only eriophyoids found on wheat varieties. The WCM variants were also found on alternate host plants, including some plants not known to host WCM. These results have implications for the control of this pest within Australian cereal crops. PMID:19224660

Carew, M; Schiffer, M; Umina, P; Weeks, A; Hoffmann, A

2009-10-01

316

Relationship Between Fatigue Index and Number of Repetition Maxima with Sub-Maximal Loads in Biceps Curl  

PubMed Central

The aim of this study was to investigate the relationship between the number of repetition maxima to volitional failure (RM) at 60%, 75%, 90% of 1RM and fatigue index (FI), a determinant of the muscular endurance level. Thirty four resistance trained male participants attended two testing sessions. The first session was conducted to assess 1RM load and RM at 60%, 75% and 90% of 1RM in the supine biceps curl (SBC) exercise. In the second session, a FI test protocol consisting of five sets of SBC with 90 s rest between sets was performed to determine FI values. Each set was performed to volitional failure using a sub-maximal load in the range of 15-20RM. Hypothetical high FI and low FI groups (17 participants with the highest and lowest FI values, respectively) were formed for statistical analyses. ANOVA results revealed that RM at 60%, 75%, 90% of 1RM were not significantly different between FI groups when controlled for mean repetition tempo (p=0.11, p=0.38, p=0.13, respectively). Pearson’s correlation coefficients revealed that no significant relationship was present between FI values and RM at 60%, 75%, 90% of 1RM (p=0.40, p=0.46, p=0.14, respectively). In conclusion, the muscular endurance level of participants defined in terms of FI value was not an indicator of RM in SBC. Therefore, athletes with different muscular endurance levels can use similar percentages of 1RM in biceps curl exercise in their training programs when the aim is to elicit training adaptations related to specific RM zones. PMID:24235992

Pekünlü, Ekim; Atala?, Ozan

2013-01-01

317

Leaf death and decomposition during pasture regrowth  

Microsoft Academic Search

Data are presented that describe the pattern of leaf death per ramet and per unit area. Leaf death per ramet was influenced by the number of leaves that died and the weight of the dead leaves. Leaf weight was important in determining differences in seasonal and species death rate per ramet.Leaf death rates reached a maximum of 56 lb D.M.

W. F. Hunt

1971-01-01

318

7 CFR 29.3036 - Leaf surface.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Leaf surface. 29.3036 Section 29...and Foreign Type 93) § 29.3036 Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2013-01-01

319

7 CFR 29.2528 - Leaf.  

Code of Federal Regulations, 2012 CFR

...Agriculture 2 2012-01-01 2012-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture...Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2012-01-01

320

7 CFR 29.3525 - Leaf.  

Code of Federal Regulations, 2012 CFR

...Agriculture 2 2012-01-01 2012-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture...35, 36, 37 and Foreign Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2012-01-01

321

7 CFR 29.3033 - Leaf.  

Code of Federal Regulations, 2013 CFR

...Agriculture 2 2013-01-01 2013-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture...s. Type 31 and Foreign Type 93) § 29.3033 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2013-01-01

322

7 CFR 29.3525 - Leaf.  

Code of Federal Regulations, 2014 CFR

...Agriculture 2 2014-01-01 2014-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture...35, 36, 37 and Foreign Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2014-01-01

323

7 CFR 29.1028 - Leaf.  

Code of Federal Regulations, 2011 CFR

...Agriculture 2 2011-01-01 2011-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture...12, 13, 14 and Foreign Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2011-01-01

324

7 CFR 29.3033 - Leaf.  

Code of Federal Regulations, 2010 CFR

...Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture...s. Type 31 and Foreign Type 93) § 29.3033 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2010-01-01

325

7 CFR 29.3036 - Leaf surface.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Leaf surface. 29.3036 Section 29...and Foreign Type 93) § 29.3036 Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2010-01-01

326

7 CFR 29.1028 - Leaf.  

Code of Federal Regulations, 2010 CFR

...Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture...12, 13, 14 and Foreign Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2010-01-01

327

7 CFR 29.3525 - Leaf.  

Code of Federal Regulations, 2013 CFR

...Agriculture 2 2013-01-01 2013-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture...35, 36, 37 and Foreign Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2013-01-01

328

7 CFR 29.2528 - Leaf.  

Code of Federal Regulations, 2011 CFR

...Agriculture 2 2011-01-01 2011-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture...Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2011-01-01

329

7 CFR 29.3033 - Leaf.  

Code of Federal Regulations, 2012 CFR

...Agriculture 2 2012-01-01 2012-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture...s. Type 31 and Foreign Type 93) § 29.3033 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2012-01-01

330

7 CFR 29.2528 - Leaf.  

Code of Federal Regulations, 2013 CFR

...Agriculture 2 2013-01-01 2013-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture...Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2013-01-01

331

7 CFR 29.3036 - Leaf surface.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Leaf surface. 29.3036 Section 29...and Foreign Type 93) § 29.3036 Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2012-01-01

332

7 CFR 29.1028 - Leaf.  

Code of Federal Regulations, 2012 CFR

...Agriculture 2 2012-01-01 2012-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture...12, 13, 14 and Foreign Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2012-01-01

333

7 CFR 29.3036 - Leaf surface.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Leaf surface. 29.3036 Section 29...and Foreign Type 93) § 29.3036 Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2011-01-01

334

7 CFR 29.1028 - Leaf.  

Code of Federal Regulations, 2014 CFR

...Agriculture 2 2014-01-01 2014-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture...12, 13, 14 and Foreign Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2014-01-01

335

7 CFR 29.1028 - Leaf.  

Code of Federal Regulations, 2013 CFR

...Agriculture 2 2013-01-01 2013-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture...12, 13, 14 and Foreign Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2013-01-01

336

7 CFR 29.3525 - Leaf.  

Code of Federal Regulations, 2011 CFR

...Agriculture 2 2011-01-01 2011-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture...35, 36, 37 and Foreign Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2011-01-01

337

7 CFR 29.2528 - Leaf.  

Code of Federal Regulations, 2014 CFR

...Agriculture 2 2014-01-01 2014-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture...Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2014-01-01

338

7 CFR 29.3036 - Leaf surface.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Leaf surface. 29.3036 Section 29...and Foreign Type 93) § 29.3036 Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2014-01-01

339

7 CFR 29.3033 - Leaf.  

Code of Federal Regulations, 2014 CFR

...Agriculture 2 2014-01-01 2014-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture...s. Type 31 and Foreign Type 93) § 29.3033 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2014-01-01

340

7 CFR 29.3033 - Leaf.  

Code of Federal Regulations, 2011 CFR

...Agriculture 2 2011-01-01 2011-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture...s. Type 31 and Foreign Type 93) § 29.3033 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip...

2011-01-01

341

Very Sparse Leaf Languages Lance Fortnow  

E-print Network

Very Sparse Leaf Languages Lance Fortnow Department of Computer Science University of Chicago studied the balanced leaf languages defined via poly-logarithmically sparse leaf pattern sets. Unger shows that NP-complete sets are not polynomial-time many-one reducible to such balanced leaf language unless

Fortnow, Lance

342

Very Sparse Leaf Languages # Lance Fortnow +  

E-print Network

Very Sparse Leaf Languages # Lance Fortnow + Department of Computer Science University of Chicago studied the balanced leaf languages defined via poly­logarithmically sparse leaf pattern sets. Unger shows that NP­complete sets are not polynomial­time many­one reducible to such balanced leaf language unless

Fortnow, Lance

343

Near infrared leaf reflectance modeling  

NASA Technical Reports Server (NTRS)

Near infrared leaf reflectance modeling using Fresnel's equation (Kumar and Silva, 1973) and Snell's Law successfully approximated the spectral curve for a 0.25-mm turgid oak leaf lying on a Halon background. Calculations were made for ten interfaces, air-wax, wax-cellulose, cellulose-water, cellulose-air, air-water, and their inverses. A water path of 0.5 mm yielded acceptable results, and it was found that assignment of more weight to those interfaces involving air versus water or cellulose, and less to those involving wax, decreased the standard deviation of the error for all wavelengths. Data suggest that the air-cell interface is not the only important contributor to the overall reflectance of a leaf. Results also argue against the assertion that the near infrared plateau is a function of cell structure within the leaf.

Parrish, J. B.

1985-01-01

344

Hormonal Regulation of Leaf Abscission  

PubMed Central

A review is given of the progress made during the last 6 years in elucidating the nature, locus of action, and transport properties of the endogenous hormones that control leaf abscission. PMID:16657014

Jacobs, William P.

1968-01-01

345

Involvement of ethylene biosynthesis and signalling in fruit set and early fruit development in zucchini squash (Cucurbita pepo L.)  

PubMed Central

Background We have identified a kind of parthenocarpy in zucchini squash which is associated with an incomplete andromonoecy, i.e. a partial conversion of female into bisexual flowers. Given that andromonoecy in this and other cucurbit species is caused by a reduction of ethylene production in the female flower, the associated parthenocarpic development of the fruit suggested the involvement of ethylene in fruit set and early fruit development. Results We have compared the production of ethylene as well as the expression of 13 ethylene biosynthesis and signalling genes in pollinated and unpollinated ovaries/fruits of two cultivars, one of which is parthenocarpic (Cavili), while the other is non-parthenocarpic (Tosca). In the latter, unpollinated ovaries show an induction of ethylene biosynthesis and ethylene signal transduction pathway genes three days after anthesis, which is concomitant with the initiation of fruit abortion and senescence. Fruit set and early fruit development in pollinated flowers of both cultivars and unpollinated flowers of Cavili is coupled with low ethylene biosynthesis and signalling, which would also explain the partial andromonoecy in the parthenocarpic genotype. The reduction of ethylene production in the ovary cosegregates with parthenocarpy and partial andromonoecy in the selfing progeny of Cavili. Moreover, the induction of ethylene in anthesis (by ethephon treatments) reduced the percentage of bisexual parthenocarpic flowers in Cavili, while the inhibition of ethylene biosynthesis or response (by AVG and STS treatments) induces not only andromonoecy but also the parthenocarpic development of the fruit in both cultivars. Conclusions Results demonstrate that a reduction of ethylene production or signalling in the zucchini flower is able to induce fruit set and early fruit development, and therefore that ethylene is actively involved in fruit set and early fruit development. Auxin and TIBA treatments, inducing fruit set and early fruit development in this species, also inhibit ethylene production and the expression of ethylene biosynthesis and response genes. A model is presented that discusses the crosstalk between ethylene and auxin in the control of fruit set and early fruit development in zucchini squash. PMID:24053311

2013-01-01

346

Stem-and-Leaf Plots  

NSDL National Science Digital Library

This lesson is designed to introduce students to stem-and-leaf plots as a graphical way to represent a data set. The lesson also reviews measures of central tendency. This lesson provides links to discussions and activities related to stem-and-leaf plots as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2010-01-01

347

Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups  

Microsoft Academic Search

Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf\\u000a dark respiration rate (R\\u000a d) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic\\u000a capacity (A\\u000a max). However, it is not known whether such scaling, if it exists, is similar among

Peter B. Reich; Michael B. Walters; David S. Ellsworth; James M. Vose; John C. Volin; Charles GreshamWilliam; William D. Bowman

1998-01-01

348

Leaf exsertion, leaf elongation, and leaf senescence in Eriophorum vaginatum and Carex Bigelowii  

SciTech Connect

Most of the common sedges of arctic vegetation show a pattern of leaf production in which the exsertion and elongation of new leaves is more or less simultaneous with the senescence of old leaves. The present study was designed to increase our understanding of the variability sequential leaf production by arctic sedges, and to determine some of the controls on that variability. We did this in two ways: first, we compared the sequential patterns of leaf growth and senescence in E. vaginatum with those of Carex Bigelowii Torr. at two tussock tundra sites near Toolik Lake on the North Slope of Alaska. Second, we compared the responses of leaf growth in these species in control and fertilized plots and in two microenvironments thought to differ sharply in nutrient availability and total productivity. 29 refs., 28 figs., 2 tabs.

Shaver, G.R.; Yandow, T.; Laundre, J.

1990-01-01

349

Edge principal components and squash clustering: using the special structure of phylogenetic placement data for sample comparison.  

PubMed

Principal components analysis (PCA) and hierarchical clustering are two of the most heavily used techniques for analyzing the differences between nucleic acid sequence samples taken from a given environment. They have led to many insights regarding the structure of microbial communities. We have developed two new complementary methods that leverage how this microbial community data sits on a phylogenetic tree. Edge principal components analysis enables the detection of important differences between samples that contain closely related taxa. Each principal component axis is a collection of signed weights on the edges of the phylogenetic tree, and these weights are easily visualized by a suitable thickening and coloring of the edges. Squash clustering outputs a (rooted) clustering tree in which each internal node corresponds to an appropriate "average" of the original samples at the leaves below the node. Moreover, the length of an edge is a suitably defined distance between the averaged samples associated with the two incident nodes, rather than the less interpretable average of distances produced by UPGMA, the most widely used hierarchical clustering method in this context. We present these methods and illustrate their use with data from the human microbiome. PMID:23505415

Matsen, Frederick A; Evans, Steven N

2013-01-01

350

Edge Principal Components and Squash Clustering: Using the Special Structure of Phylogenetic Placement Data for Sample Comparison  

PubMed Central

Principal components analysis (PCA) and hierarchical clustering are two of the most heavily used techniques for analyzing the differences between nucleic acid sequence samples taken from a given environment. They have led to many insights regarding the structure of microbial communities. We have developed two new complementary methods that leverage how this microbial community data sits on a phylogenetic tree. Edge principal components analysis enables the detection of important differences between samples that contain closely related taxa. Each principal component axis is a collection of signed weights on the edges of the phylogenetic tree, and these weights are easily visualized by a suitable thickening and coloring of the edges. Squash clustering outputs a (rooted) clustering tree in which each internal node corresponds to an appropriate “average” of the original samples at the leaves below the node. Moreover, the length of an edge is a suitably defined distance between the averaged samples associated with the two incident nodes, rather than the less interpretable average of distances produced by UPGMA, the most widely used hierarchical clustering method in this context. We present these methods and illustrate their use with data from the human microbiome. PMID:23505415

Matsen IV, Frederick A.; Evans, Steven N.

2013-01-01

351

Significance of leaf orientation for leaf temperature in an Amazonian sclerophyll vegetation.  

PubMed

The influence of leaf orientation on leaf temperature has been studied in an sclerophyll vegetation of the Amazon basin, which grows on white sandy soils of very low water retention capacity and variable depth of the water table. Leaf size of the species studied is mainly mesophyllous (sensu Raunkiaer). The high degree of leaf inclination in all species is very characteristic; 55% of the leaves present inclination angles (relative to the vertical) smaller than 45 degrees. Water potential is generally high, not being lower than -14 bars. Leaf resistance increases toward noon during the course of sunny days, indicating either water stress at leaf level or the influence of low relative humidity on stomata opening. Leaf temperature under sunny conditions reflects the influence of leaf orientation on the amount of radiation absorbed by the leaf. Temperature differences recorded range from 1.8--5.4 degrees C. The difference depends on leaf angle, leaf color and leaf diffusion resistance during the period of measurement. Analysis of the relationship between leaf angle and leaf temperature, using Gates leaf energy balance, shows that under the conditions prevailing at noon in sunny days, leaf angles smaller than 50 degrees are effective in reducing leaf temperature within a wide range of leaf resistances to water vapor transfer. PMID:724979

Medina, E; Sobrado, M; Herrera, R

1978-08-10

352

Temporal and spatial patterns in wind stress and wind stress curl over the central Southern California Bight  

USGS Publications Warehouse

In 2001, the U.S. Geological Survey, together with several other federal and municipal agencies, began a series of field programs to determine along and cross-shelf transport patterns over the continental shelves in the central Southern California Bight. As a part of these programs, moorings that monitor winds were deployed off the Palos Verdes peninsula and within San Pedro Bay for six 3–4 month summer and winter periods between 2001 and 2008. In addition, nearly continuous records of winds for this 7-year period were obtained from a terrestrial site at the coast and from a basin site offshore of the long-term coastal site. The mean annual winds are downcoast at all sites. The alongshelf components of wind stress, which are the largest part of the low-frequency wind stress fields, are well correlated between basin, shelf and coastal sites. On average, the amplitude of alongshelf fluctuations in wind stress are 3–4 times larger over the offshore basin, compared to the coastal site, irrespective of whether the fluctuations represent the total, or just the correlated portion of the wind stress field. The curl in the large-scale wind stress tends to be positive, especially in the winter season when the mean wind stress is downcoast and larger at the offshore basin site than at the beach. However, since the fluctuation in wind stress amplitudes are usually larger than the mean, periods of weak negative curl do occur, especially in the summer season when the largest normalized differences in the amplitude of wind stress fluctuations are found in the nearshore region of the coastal ocean. Even though the low-frequency wind stress field is well-correlated over the continental shelf and offshore basins, out to distances of 35 km or more from the coast, winds even 10 km inshore of the beach do not represent the coastal wind field, at least in the summer months. The seasonal changes in the spatial structures in wind stress amplitudes suggest that an assessment of the amplitude of the responses of coastal ocean processes to wind forcing is complex and that the responses may have significant seasonal structures.

Noble, Marlene A.; Rosenberger, Kurt J.; Rosenfeld, Leslie K.; Robertson, George L.

2012-01-01

353

Application of Failure Mode and Effect Analysis (FMEA), cause and effect analysis, and Pareto diagram in conjunction with HACCP to a corn curl manufacturing plant.  

PubMed

The Failure Mode and Effect Analysis (FMEA) model has been applied for the risk assessment of corn curl manufacturing. A tentative approach of FMEA application to the snacks industry was attempted in an effort to exclude the presence of GMOs in the final product. This is of crucial importance both from the ethics and the legislation (Regulations EC 1829/2003; EC 1830/2003; Directive EC 18/2001) point of view. The Preliminary Hazard Analysis and the Fault Tree Analysis were used to analyze and predict the occurring failure modes in a food chain system (corn curls processing plant), based on the functions, characteristics, and/or interactions of the ingredients or the processes, upon which the system depends. Critical Control points have been identified and implemented in the cause and effect diagram (also known as Ishikawa, tree diagram, and the fishbone diagram). Finally, Pareto diagrams were employed towards the optimization of GMOs detection potential of FMEA. PMID:17457722

Varzakas, Theodoros H; Arvanitoyannis, Ioannis S

2007-01-01

354

Leaf Senescence and GABA Shunt  

PubMed Central

Leaf senescence is highly regulated and complex developmental process that involves degradation of macromolecules as well as its recycling. Senescence process involves loss of chlorophyll, degradation of proteins, nucleic acid, lipid and mobilization of nutrients through its transport to the growing parts, developing fruits and seeds. Nitrogen is the most important nutrient to be recycled in senescence process. GABA-transaminase (?-aminobutyric acid) is found to play very important role in nitrogen recycling process through GABA-shunt. Therefore, it is of interest to review the significance of GABA shunt in leaf senescence.

Ansari, Mohammad Israil; Hasan, Saba; Jalil, Syed Uzma

2014-01-01

355

Life in the Leaf Litter  

NSDL National Science Digital Library

Produced by the Center for Biodiversity and Conservation, Life in the Leaf Litter is a guide to the diversity of soil organisms and the crucial role that invertebrates play in woodland ecosystems. The booklet was based, in part, on a leaf litter survey conducted by the CBC's Metro Program and the Museum's Division of Invertebrate Zoology in Central Park's woodlands, which led to the discovery of a new genus and species of centipede, Nannarrup hoffmani. The booklet may be downloaded as a pdf or ordered free of charge.

356

Estimating leaf biochemistry using the PROSPECT leaf optical properties model  

Microsoft Academic Search

The biophysical, biochemical, and optical properties of 63 fresh leaves and 58 dry leaves were measured to investigate the potential of remote sensing to estimate the leaf biochemistry from space. Almost 2000 hemispherical reflectance and transmittance spectra were acquired from 400 nm to 2500 nm using a laboratory spectrophotometer. The amount of chlorophyll, water, protein, cellulose, hemicellulose, lignin, and starch

S. Jacquemoud; S. L. Ustin; J. Verdebout; G. Schmuck; G. Andreoli; B. Hosgood

1996-01-01

357

7 CFR 28.471 - Below Leaf Grade Cotton.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471...TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is...

2013-01-01

358

7 CFR 28.471 - Below Leaf Grade Cotton.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471...TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is...

2012-01-01

359

7 CFR 28.471 - Below Leaf Grade Cotton.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471...TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is...

2014-01-01

360

7 CFR 28.471 - Below Leaf Grade Cotton.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471...TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is...

2010-01-01

361

7 CFR 28.471 - Below Leaf Grade Cotton.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471...TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is...

2011-01-01

362

Spectral reflectance relationships to leaf water stress  

NASA Technical Reports Server (NTRS)

Spectral reflectance data were collected from detached snapbean leaves in the laboratory with a multiband radiometer. Four experiments were designed to study the spectral response resulting from changes in leaf cover, relative water content of leaves, and leaf water potential. Spectral regions included in the analysis were red (630-690 nm), NIR (760-900 nm), and mid-IR (2.08-2.35 microns). The red and mid-IR bands showed sensitivity to changes in both leaf cover and relative water content of leaves. The NIR was only highly sensitive to changes in leaf cover. Results provided evidence that mid-IR reflectance was governed primarily by leaf moisture content, although soil reflectance was an important factor when leaf cover was less than 100 percent. High correlations between leaf water potentials and reflectance were attributed to covariances with relative water content of leaves and leaf cover.

Ripple, William J.

1986-01-01

363

An Innovative Way to Monitor Leaf Age  

NASA Astrophysics Data System (ADS)

Anthony John Garnello, Karina Paredes, Uyen Khanh Ho Trinh, Jin Wu, Scott Saleska Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA Abstract: Leaf age is an important characteristic for controlling plant functional performance and is associated with the changes of leaf physical, chemical, and physiological properties. Understanding how plant physiology changes over time will allow more accurate predictions of growth patterns, and a more comprehensive understanding of vegetative life histories. There still lacks an efficient technique in monitoring leaf age, tagging leaves is still the only way to accurately monitor leaf age. The goal of this study is to develop a multi-metric, accurate technique for better monitoring of leaf age. In order to acquire true leaf age records, 10 individual plant species were selected at the University of Arizona campus, and newly flushing leaves were tagged and monitored during the Monsoon season (from early June, 2013, to mid October, 2013). Every 2 weeks, 10 to 15 leaves in relative age order were harvested from each 1-meter branch to measure multiple key leaf metrics, including leaf thickness (via micrometer), fresh and dry weight, fresh and dry area (via ImageJ software), and leaf hyperspectral reflectance (via a handheld ASD Field Pro). Other leaf traits were also derived from our measurements, such as specific leaf area (SLA), leaf density (fresh weight/leaf volume), water percentage, and shrinkage ratio (1-dry area/fresh area). The hyperspectral version of vegetation index (a ratio derived from two spectral channels) was generated for each branch sample, by randomly selecting two channels from within the spectral domain of 350 nm to 2500 nm. The preliminary result documents three types of hyperspectral vegetation index (VI) which are highly related with leaf relative age order (R2>0.9). These include the sensitive spectral domains correlated with (a) leaf pigments (~550nm) and leaf physical structure (750nm-1000nm), (b) leaf pigments (~550nm) and leaf water concentration (1400nm-2300nm), and (c) leaf physical structure (750nm-1000nm) and leaf water concentration (1400nm-2300nm). Preliminary results showed that (1) among the key leaf traits, leaf shrinkage is the only trait that showed a consistent correlation with relative age order across the samples; (2) a power function best modeled the interspecies relationship between leaf shrinkage and leaf age (R2 = 0.81, p-value < 0.01, 22 data points for 7 species); (3) a strong correlation was found between the predicted leaf age using the species specific power functions of leaf shrinkage and true leaf age (R2= 0.96, p-value < 0.01), suggesting that leaf shrinkage could be a useful trait for prediction of absolute leaf age in the future. In the next step, we will integrate leaf shrinkage based leaf age prediction with hyperspectral VI framework, aiming to derive some reliable VIs which can be universal for leaf aging prediction among all the species.

Garnello, A.; Paredes, K.; Trinh, U.; Saleska, S. R.; Wu, J.

2013-12-01

364

7 CFR 30.2 - Leaf tobacco.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture...STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of...

2014-01-01

365

7 CFR 30.2 - Leaf tobacco.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture...STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of...

2012-01-01

366

7 CFR 30.2 - Leaf tobacco.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture...STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of...

2011-01-01

367

7 CFR 30.2 - Leaf tobacco.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture...STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of...

2010-01-01

368

7 CFR 30.2 - Leaf tobacco.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture...STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of...

2013-01-01

369

Population genetics of the wheat curl mite (Aceria tosichella Keifer) in Australia: implications for the management of wheat pathogens.  

PubMed

The wheat curl mite (WCM), Aceria tosichella Keifer, is a polyphagous eriophyoid mite and the primary vector of wheat streak mosaic virus (WSMV) and five other viral pathogens in cereals. Previous research using molecular markers and a series of laboratory experiments found A. tosichella in Australia to consist of two genetically distinct lineages, which have broad overlapping distributions and differ in their ability to transmit WSMV under controlled conditions. This pattern of transmission also appears to be apparent in the field, whereby a strong association between WSMV detection and a single WCM lineage has been detected. In this study, we conduct a population genetic analysis and provide information on the genetic structure of the Australian viruliferous WCM lineage. We assessed genetic differentiation of 16 WCM populations using nine microsatellite markers. Strong evidence for extensive gene flow and low genetic structuring throughout the Australian wheatbelt was evident, with an exception for Western Australian and far north Queensland populations that appear to be genetically isolated. The data also indicate genetic patterns consistent with an arrhenotokous parthenogenetic mode of reproduction. Implications of these findings are discussed with reference to the management of WCM and associated cereal pathogens in Australia and overseas. PMID:22030277

Miller, A D; Umina, P A; Weeks, A R; Hoffmann, A A

2012-04-01

370

Influence of volunteer wheat plant condition on movement of the wheat curl mite, Aceria tosichella, in winter wheat.  

PubMed

The wheat curl mite (WCM), Aceria tosichella Keifer, is the vector of wheat streak mosaic virus and high plains virus which cause significant crop loss in winter wheat throughout the western Great Plains. Volunteer wheat emerging before harvest, as a result of severe hail, is the primary source of mites and virus that infect fall-planted winter wheat. Wind-borne movement of the WCM is of key importance in the spread and infection of the virus complex. Significant movement of WCM from wheat has been thought to be closely tied to the senescence or deterioration of the host. Results from field and greenhouse studies indicated that movement from un-vernalized winter wheat was not closely associated with the deterioration of the wheat host. Greenhouse studies showed no correlation between WCM movement and plant condition, but there was a highly significant relationship between WCM movement and mite population on the host plant. Field studies did not demonstrate increased movement associated with deteriorating un-vernalized winter wheat. However, healthier hosts which were able to support a larger population of mites were associated with increased movement. The main influence on the level of mite movement relates to the size of the source population and not the condition of the host plant, but plant condition appears to be a factor in limiting the increase of the WCM population. PMID:14974690

Thomas, John A; Hein, Gary L

2003-01-01

371

Perturbation solution of the Navier-Stokes equations and its relation to the Lighthill-Curle solution of aerodynamic sound  

NASA Technical Reports Server (NTRS)

The aerodynamic sound described by the Lighthill-Curle solution is reexamined using a method of matched asymptotic expansions. The governing Navier-Stokes equations written in nondimensional form are expanded for a small Mach number. First- and second-order solutions for the pressure field are obtained, and the singular nature of the expansion at large distances is indicated. The nearfield pressure is governed by the Poisson equation, whereas the farfield equations describe a linear wave system in a dissipative medium. The pseudosound is related to the incompressible Reynolds stresses associated with a solenoidal velocity field, the velocity, the pressure perturbation, and their derivatives on the boundaries. A uniformly valid first-order solution for the pressure is obtained. It is shown that viscosity, thermal conductivity, and entropy in the flow do not contribute to the first-order noise generation, while the viscous stress contributes to noise only from some boundaries. The application of the proposed perturbation method to a subsonically moving surface and a hot jet is discussed.

Pan, Y. S.

1975-01-01

372

Potential new sources of wheat curl mite resistance in wheat to prevent the spread of yield-reducing pathogens.  

PubMed

The wheat curl mite (WCM), Aceria tosichella Keifer (Trombidiformes: Eriophyidae), is a major pest in cropping regions of the world and is recognised as the primary vector of several yield-reducing pathogens, primarily affecting wheat. Management of WCM is complicated due to several aspects of the mite's biology and ecology; however, commercially viable mite resistant wheat varieties may offer practical long-term management options. Unfortunately, mite populations have adapted to previously identified sources of resistance, highlighting the need for further sources of resistance and the value of stacking different resistances to give greater degrees and longevity of control. In this study we assessed the susceptibility of 42 wheat-derived genotypes to mite population growth using a new experimental method that overcomes methodological limitations of previous studies. Experimental wheat lines included a variety of wheat genotypes, related Triticeae species, wheat-alien chromosome amphiploids, and chromosome addition or substitution lines. From these we identify new promising sources of WCM resistance associated with Thinopyrum intermedium, Th. ponticum and Hordeum marinum chromosomes. More specifically we identify group 1J and 5J chromosomes of the L3 and L5 wheat-Th. intermedium addition lines as new sources of resistance that could be exploited to transfer resistance onto homoeologous wheat chromosomes. This study offers new methods for reliable in situ estimations of mite abundance on cereal plants, and new sources of WCM resistance that may assist management of WCM and associated viruses in wheat. PMID:24705793

Richardson, Kelly; Miller, Adam D; Hoffmann, Ary A; Larkin, Philip

2014-09-01

373

Relation between the wind stress curl in the North Atlantic and the Atlantic inflow to the Nordic Seas  

NASA Astrophysics Data System (ADS)

In this study an isopycnic coordinate ocean model has been used to investigate the relationships between the North Atlantic wind stress curl (WSC) and the inflow of Atlantic water to the Nordic Seas. For the period 1995-2001, there is a maximum in the correlation between the zonally averaged WSC at 55°N and the inflow with a 15-month time lag, capturing a relation already found in observational data. In the model this relation is linked to the mixing along the western flank of the Rockall Bank (56°N, 15°W). For the period 1995-2001 the atmospheric forcing in the northeastern North Atlantic is relatively weak, and the depth of the mixed layer is shallower than the sill depths of the Greenland-Scotland Ridge (GSR). Slowly moving, baroclinic disturbances caused by anomalies in the wind forcing will then be transmitted into the Nordic Seas where they are recorded as anomalous volume transports in the Norwegian Atlantic Current. In contrast, for the pentad prior to this period the atmospheric forcing is much more intense, and generates mixing well below sill depths of the GSR for all winters. Baroclinic disturbances forced by variations in the atmospheric forcing will then tend to follow f/H contours that do not enter the Nordic Seas, and the 15-month lagged relations between the wind and the volume transports will vanish. Recent observational data support this view.

Sandø, A. B.; Furevik, T.

2008-06-01

374

The gauge dual of a warped product of AdS4 and a squashed and stretched seven-manifold  

NASA Astrophysics Data System (ADS)

Corrado, Pilch and Warner found in 2001 the second 11-dimensional solution where the deformed geometry of S7 in the lift contains S2 × S2. We identify the gauge dual of this background with the theory described by Franco, Klebanov and Rodriguez-Gomez recently. It is the U(N) × U(N) × U(N) gauge theory with two SU(2) doublet chiral fields B1 transforming in the ({\\bf N}, \\overline{\\bf N}, {\\bf 1}), B2 transforming in the ({\\bf 1}, {\\bf N}, \\overline{\\bf N}), C1 in the ({\\bf 1}, \\overline{\\bf N}, {\\bf N}) and C2 in the (\\overline{\\bf N}, {\\bf N}, {\\bf 1}) as well as an adjoint field ? in the (1, adj, 1) representation. By adding the mass term for adjoint field ?, the detailed correspondence between fields of AdS4 supergravity and composite operators of the IR field theory is determined. Moreover, we compute the spin-2 KK modes around a warped product of AdS4 and a squashed and stretched seven-manifold. This background with global SU(2) × SU(2) × U(1)R symmetry is related to a U(N) × U(N) × U(N) {\\cal N}=2 superconformal Chern-Simons matter theory with eighth-order superpotential and Chern-Simons level (1, 1, -2). The mass-squared in AdS4 depends on SU(2) × SU(2) × U(1)R quantum numbers and the KK excitation number. The dimensions of spin-2 operators are found.

Ahn, Changhyun; Woo, Kyungsung

2010-02-01

375

Remote estimation of leaf area index and green leaf biomass in maize canopies  

E-print Network

Remote estimation of leaf area index and green leaf biomass in maize canopies Anatoly A. Gitelson,1 750 nm). The technique was tested in agricultural fields under a maize canopy, and proved suitable of leaf area index and green leaf biomass in maize canopies, Geophys. Res. Lett., 30(5), 1248, doi:10

Gitelson, Anatoly

376

LEAF: A Microcomputer Program for Constructing the Tukey Stem and Leaf Graph.  

ERIC Educational Resources Information Center

This paper presents a BASIC microcomputer program that constructs the Tukey (1977) stem and leaf graph. Options within the LEAF program include a modified stem and leaf where the stem is split and a parallel stem and leaf graph where two separate sets of data are displayed from a common stem. (Author)

Pascale, Pietro J.; Smith, Joseph

1986-01-01

377

Leaf number, water stress and carbon nutrition effects on poplar leaf growth  

E-print Network

Leaf number, water stress and carbon nutrition effects on poplar leaf growth J.P. Gaudillère area of a leaf is described by the number and the mean size of epidermal cells. Water stress, nitrogen at different levels in the process of leaf production. The main susceptible physio- logical mechanisms are cell

Paris-Sud XI, Université de

378

7 CFR 29.3528 - Leaf surface.  

Code of Federal Regulations, 2014 CFR

...TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign...3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2014-01-01

379

7 CFR 29.3528 - Leaf surface.  

Code of Federal Regulations, 2012 CFR

...TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign...3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2012-01-01

380

7 CFR 29.3528 - Leaf surface.  

Code of Federal Regulations, 2010 CFR

...TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign...3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2010-01-01

381

7 CFR 29.3528 - Leaf surface.  

Code of Federal Regulations, 2013 CFR

...TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign...3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2013-01-01

382

7 CFR 29.3528 - Leaf surface.  

Code of Federal Regulations, 2011 CFR

...TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign...3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to...

2011-01-01

383

7 CFR 29.2278 - Leaf structure.  

Code of Federal Regulations, 2010 CFR

...2 2010-01-01 2010-01-01 false Leaf structure. 29.2278 Section 29.2278 Agriculture ...Fire-Cured Tobacco (u.s. Type 21) § 29.2278 Leaf structure. The cell development of a leaf as indicated by its...

2010-01-01

384

7 CFR 29.2278 - Leaf structure.  

Code of Federal Regulations, 2011 CFR

...2 2011-01-01 2011-01-01 false Leaf structure. 29.2278 Section 29.2278 Agriculture ...Fire-Cured Tobacco (u.s. Type 21) § 29.2278 Leaf structure. The cell development of a leaf as indicated by its...

2011-01-01

385

7 CFR 29.2277 - Leaf scrap.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture...Tobacco (u.s. Type 21) § 29.2277 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2013-01-01

386

7 CFR 29.3034 - Leaf scrap.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture...Type 31 and Foreign Type 93) § 29.3034 Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2014-01-01

387

7 CFR 29.3034 - Leaf scrap.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture...Type 31 and Foreign Type 93) § 29.3034 Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2013-01-01

388

7 CFR 29.3034 - Leaf scrap.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture...Type 31 and Foreign Type 93) § 29.3034 Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2010-01-01

389

7 CFR 29.2278 - Leaf structure.  

Code of Federal Regulations, 2013 CFR

...2 2013-01-01 2013-01-01 false Leaf structure. 29.2278 Section 29.2278...Fire-Cured Tobacco (u.s. Type 21) § 29.2278 Leaf structure. The cell development of a leaf as indicated by its porosity. (See...

2013-01-01

390

7 CFR 29.3526 - Leaf scrap.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture...36, 37 and Foreign Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2012-01-01

391

7 CFR 29.2277 - Leaf scrap.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture...Tobacco (u.s. Type 21) § 29.2277 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2010-01-01

392

7 CFR 29.2278 - Leaf structure.  

Code of Federal Regulations, 2014 CFR

...2 2014-01-01 2014-01-01 false Leaf structure. 29.2278 Section 29.2278...Fire-Cured Tobacco (u.s. Type 21) § 29.2278 Leaf structure. The cell development of a leaf as indicated by its porosity. (See...

2014-01-01

393

7 CFR 29.2277 - Leaf scrap.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture...Tobacco (u.s. Type 21) § 29.2277 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2014-01-01

394

7 CFR 29.2278 - Leaf structure.  

Code of Federal Regulations, 2012 CFR

...2 2012-01-01 2012-01-01 false Leaf structure. 29.2278 Section 29.2278...Fire-Cured Tobacco (u.s. Type 21) § 29.2278 Leaf structure. The cell development of a leaf as indicated by its porosity. (See...

2012-01-01

395

On magnetic leaf-wise intersections  

E-print Network

In this article we introduce the notion of a magnetic leaf-wise intersection point which is a generalization of the leaf-wise intersection point with magnetic effects. We also prove the existence of magnetic leaf-wise intersection points under certain topological assumptions.

Bae, Youngjin

2011-01-01

396

7 CFR 29.2277 - Leaf scrap.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture...Tobacco (u.s. Type 21) § 29.2277 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2012-01-01

397

7 CFR 29.2277 - Leaf scrap.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf scrap. 29.2277 Section 29.2277 Agriculture...Tobacco (u.s. Type 21) § 29.2277 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2011-01-01

398

7 CFR 29.3526 - Leaf scrap.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture...36, 37 and Foreign Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2013-01-01

399

7 CFR 29.3034 - Leaf scrap.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture...Type 31 and Foreign Type 93) § 29.3034 Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2011-01-01

400

7 CFR 29.3526 - Leaf scrap.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture...36, 37 and Foreign Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2014-01-01

401

7 CFR 29.3526 - Leaf scrap.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture...36, 37 and Foreign Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed...

2011-01-01

402

7 CFR 29.3034 - Leaf scrap.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture...Type 31 and Foreign Type 93) § 29.3034 Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed...

2012-01-01

403

ORIGINAL PAPER Leaf wax d2  

E-print Network

ORIGINAL PAPER Leaf wax d2 H and varve-thickness climate proxies from proglacial lake sediments Science+Business Media B.V. 2012 Abstract We present a multiproxy paleoclimate record using leaf wax Á Leaf wax Á Proglacial lake Á Varve Introduction Arctic proglacial lake sediments are excellent

Briner, Jason P.

404

Leaf Sequencing Algorithms for Segmented Multileaf Collimation  

E-print Network

Leaf Sequencing Algorithms for Segmented Multileaf Collimation Srijit Kamath, Sartaj Sahni fluence map into a leaf sequence file that controls the movement of the MLC during radiation delivery. It is imperative that the fluence map delivered using the leaf sequence file is as close as possible to the fluence

Sahni, Sartaj K.

405

Parameterized Algorithms for Directed Maximum Leaf Problems  

E-print Network

Parameterized Algorithms for Directed Maximum Leaf Problems Noga Alon 1 , Fedor V. Fomin 2 spanning tree, then D contains one with at least (n/2) 1/5 - 1 leaves. 1 Introduction The Maximum Leaf a digraph D, the Directed Maximum Leaf Out­Branching problem is the problem of finding an out­branching in D

Krivelevich, Michael

406

Original article Photosynthesis, leaf area and productivity  

E-print Network

Original article Photosynthesis, leaf area and productivity of 5 poplar clones during; The stem volume and biomass (stem + branches) production, net photosynthesis of mature leaves and leaf area found in volume production, woody biomass production, total leaf area and net photosynthesis. Above

Paris-Sud XI, Université de

407

ZONATE LEAF SPOT (CAUSED BY CRISTULARIELLA MORICOLA)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Zonate leaf spot derives it name from the occurrence of large, circular leaf lesions with distinct concentric rings. Initially the leaf lesions are light tan in color and the concentric rings are symmetrical appearing as a ‘bulls eye’. Initial lesions are 5-10 mm in diameter and continue to expand...

408

7 CFR 29.1162 - Leaf (B Group).  

Code of Federal Regulations, 2011 CFR

...percent may be waste. B4G—Fair Quality Green Leaf Immature, close leaf structure...percent may be waste. B5G—Low Quality Green Leaf Immature, tight leaf structure...percent may be waste. B6G—Poor Quality Green Leaf Immature, tight leaf...

2011-01-01

409

7 CFR 29.1162 - Leaf (B Group).  

Code of Federal Regulations, 2012 CFR

...percent may be waste. B4G—Fair Quality Green Leaf Immature, close leaf structure...percent may be waste. B5G—Low Quality Green Leaf Immature, tight leaf structure...percent may be waste. B6G—Poor Quality Green Leaf Immature, tight leaf...

2012-01-01

410

7 CFR 29.1162 - Leaf (B Group).  

Code of Federal Regulations, 2013 CFR

...percent may be waste. B4G—Fair Quality Green Leaf Immature, close leaf structure...percent may be waste. B5G—Low Quality Green Leaf Immature, tight leaf structure...percent may be waste. B6G—Poor Quality Green Leaf Immature, tight leaf...

2013-01-01

411

7 CFR 29.1162 - Leaf (B Group).  

Code of Federal Regulations, 2014 CFR

...percent may be waste. B4G—Fair Quality Green Leaf Immature, close leaf structure...percent may be waste. B5G—Low Quality Green Leaf Immature, tight leaf structure...percent may be waste. B6G—Poor Quality Green Leaf Immature, tight leaf...

2014-01-01

412

7 CFR 29.1162 - Leaf (B Group).  

Code of Federal Regulations, 2010 CFR

...percent may be waste. B4G—Fair Quality Green Leaf Immature, close leaf structure...percent may be waste. B5G—Low Quality Green Leaf Immature, tight leaf structure...percent may be waste. B6G—Poor Quality Green Leaf Immature, tight leaf...

2010-01-01

413

Leaf area dynamics of conifer forests  

SciTech Connect

Estimating the surface area of foliage supported by a coniferous forest canopy is critical for modeling its biological properties. Leaf area represents the surface area available for the interception of energy, the absorption of carbon dioxide, and the diffusion of water from the leaf to the atmosphere. The concept of leaf area is pertinent to the physiological and ecological dynamics of conifers at a wide range of spatial scales, from individual leaves to entire biomes. In fact, the leaf area of vegetation at a global level can be thought of as a carbon-absorbing, water-emitting membrane of variable thickness, which can have an important influence on the dynamics and chemistry of the Earth`s atmosphere over both the short and the long term. Unless otherwise specified, references to leaf area herein refer to projected leaf area, i.e., the vertical projection of needles placed on a flat plane. Total leaf surface area is generally from 2.0 to 3.14 times that of projected leaf area for conifers. It has recently been suggested that hemisurface leaf area, i.e., one-half of the total surface area of a leaf, a more useful basis for expressing leaf area than is projected area. This chapter is concerned with the dynamics of coniferous forest leaf area at different spatial and temporal scales. In the first part, we consider various hypotheses related to the control of leaf area development, ranging from simple allometric relations with tree size to more complex mechanistic models that consider the movement of water and nutrients to tree canopies. In the second part, we consider various aspects of leaf area dynamics at varying spatial and temporal scales, including responses to perturbation, seasonal dynamics, genetic variation in crown architecture, the responses to silvicultural treatments, the causes and consequences of senescence, and the direct measurement of coniferous leaf area at large spatial scales using remote sensing.

Margolis, H.; Oren, R.; Whitehead, D.; Kaufmann, M.R.

1995-07-01

414

The relationship of leaf photosynthetic traits - V cmax and J max - to leaf nitrogen, leaf phosphorus, and specific leaf area: a meta-analysis and modeling study.  

PubMed

Great uncertainty exists in the global exchange of carbon between the atmosphere and the terrestrial biosphere. An important source of this uncertainty lies in the dependency of photosynthesis on the maximum rate of carboxylation (V cmax) and the maximum rate of electron transport (J max). Understanding and making accurate prediction of C fluxes thus requires accurate characterization of these rates and their relationship with plant nutrient status over large geographic scales. Plant nutrient status is indicated by the traits: leaf nitrogen (N), leaf phosphorus (P), and specific leaf area (SLA). Correlations between V cmax and J max and leaf nitrogen (N) are typically derived from local to global scales, while correlations with leaf phosphorus (P) and specific leaf area (SLA) have typically been derived at a local scale. Thus, there is no global-scale relationship between V cmax and J max and P or SLA limiting the ability of global-scale carbon flux models do not account for P or SLA. We gathered published data from 24 studies to reveal global relationships of V cmax and J max with leaf N, P, and SLA. V cmax was strongly related to leaf N, and increasing leaf P substantially increased the sensitivity of V cmax to leaf N. J max was strongly related to V cmax, and neither leaf N, P, or SLA had a substantial impact on the relationship. Although more data are needed to expand the applicability of the relationship, we show leaf P is a globally important determinant of photosynthetic rates. In a model of photosynthesis, we showed that at high leaf N (3 gm(-2)), increasing leaf P from 0.05 to 0.22 gm(-2) nearly doubled assimilation rates. Finally, we show that plants may employ a conservative strategy of J max to V cmax coordination that restricts photoinhibition when carboxylation is limiting at the expense of maximizing photosynthetic rates when light is limiting. PMID:25473475

Walker, Anthony P; Beckerman, Andrew P; Gu, Lianhong; Kattge, Jens; Cernusak, Lucas A; Domingues, Tomas F; Scales, Joanna C; Wohlfahrt, Georg; Wullschleger, Stan D; Woodward, F Ian

2014-08-01

415

Leaf hydraulic conductance is coordinated with leaf morpho-anatomical traits and nitrogen status in the genus Oryza.  

PubMed

Leaf hydraulic conductance (K leaf) is a major determinant of photosynthetic rate in plants. Previous work has assessed the relationships between leaf morpho-anatomical traits and K leaf with woody species, but there has been very little focus on cereal crops. The genus Oryza, which includes rice (Oryza sativa) and wild species (such as O. rufipogon cv. Griff), is ideal material for identifying leaf features associated with K leaf and gas exchange. Leaf morpho-anatomical traits, K leaf, leaf N content per leaf area, and CO2 diffusion efficiency were investigated in 11 Oryza cultivars. K leaf was positively correlated with leaf thickness and related traits, and therefore positively correlated with leaf mass per area and leaf N content per leaf area, and negatively with inter-veinal distance. K leaf was also positively correlated with leaf area and its related traits, and therefore negatively correlated with the proportion of minor vein length per area. In addition, coordination between K leaf and CO2 diffusion conductance in leaves was observed. We conclude that leaf morpho-anatomical traits and N content per leaf area strongly influence K leaf. Our results suggest that more detailed anatomical and structural studies are needed to elucidate the impacts of leaf feature traits on K leaf and gas exchange in grasses. PMID:25429002

Xiong, Dongliang; Yu, Tingting; Zhang, Tong; Li, Yong; Peng, Shaobing; Huang, Jianliang

2015-02-01

416

A numerical simulation of the hole-tone feedback cycle based on an axisymmetric discrete vortex method and Curle's equation  

NASA Astrophysics Data System (ADS)

An axisymmetric numerical simulation approach to the hole-tone self-sustained oscillation problem is developed, based on the discrete vortex method for the incompressible flow field, and a representation of flow noise sources on an acoustically compact impingement plate by Curle's equation. The shear layer of the jet is represented by 'free' discrete vortex rings, and the jet nozzle and the end plate by bound vortex rings. A vortex ring is released from the nozzle at each time step in the simulation. The newly released vortex rings are disturbed by acoustic feedback. It is found that the basic feedback cycle works hydrodynamically. The effect of the acoustic feedback is to suppress the broadband noise and reinforce the characteristic frequency and its higher harmonics. An experimental investigation is also described. A hot wire probe was used to measure velocity fluctuations in the shear layer, and a microphone to measure acoustic pressure fluctuations. Comparisons between simulated and experimental results show quantitative agreement with respect to both frequency and amplitude of the shear layer velocity fluctuations. As to acoustic pressure fluctuations, there is quantitative agreement w.r.t. frequencies, and reasonable qualitative agreement w.r.t. peaks of the characteristic frequency and its higher harmonics. Both simulated and measured frequencies f follow the criterion L/uc+L/c0=n/f where L is the gap length between nozzle exit and end plate, uc is the shear layer convection velocity, c0 is the speed of sound, and n is a mode number (n={1}/{2},1,{3}/{2},…). The experimental results however display a complicated pattern of mode jumps, which the numerical method cannot capture.

Langthjem, M. A.; Nakano, M.

2005-11-01

417

Electrowetting on a lotus leaf  

PubMed Central

Electrowetting on dielectrics has been widely used to manipulate and control microliter or nanoliter liquids in micro-total-analysis systems and laboratory on a chip. We carried out experiments on electrowetting on a lotus leaf, which is quite different from the equipotential plate used in conventional electrowetting. This has not been reported in the past. The lotus leaf is superhydrophobic and a weak conductor, so the droplet can be easily actuated on it through electrical potential gradient. The capillary motion of the droplet was recorded by a high-speed camera. The droplet moved toward the counterelectrode to fulfill the actuation. The actuation speed could be of the order of 10 mm?s. The actuation time is of the order of 10 ms. PMID:19693341

Feng, Jiang-Tao; Wang, Feng-Chao; Zhao, Ya-Pu

2009-01-01

418

LeafJ: An ImageJ Plugin for Semi-automated Leaf Shape Measurement  

PubMed Central

High throughput phenotyping (phenomics) is a powerful tool for linking genes to their functions (see review1 and recent examples2-4). Leaves are the primary photosynthetic organ, and their size and shape vary developmentally and environmentally within a plant. For these reasons studies on leaf morphology require measurement of multiple parameters from numerous leaves, which is best done by semi-automated phenomics tools5,6. Canopy shade is an important environmental cue that affects plant architecture and life history; the suite of responses is collectively called the shade avoidance syndrome (SAS)7. Among SAS responses, shade induced leaf petiole elongation and changes in blade area are particularly useful as indices8. To date, leaf shape programs (e.g. SHAPE9, LAMINA10, LeafAnalyzer11, LEAFPROCESSOR12) can measure leaf outlines and categorize leaf shapes, but can not output petiole length. Lack of large-scale measurement systems of leaf petioles has inhibited phenomics approaches to SAS research. In this paper, we describe a newly developed ImageJ plugin, called LeafJ, which can rapidly measure petiole length and leaf blade parameters of the model plant Arabidopsis thaliana. For the occasional leaf that required manual correction of the petiole/leaf blade boundary we used a touch-screen tablet. Further, leaf cell shape and leaf cell numbers are important determinants of leaf size13. Separate from LeafJ we also present a protocol for using a touch-screen tablet for measuring cell shape, area, and size. Our leaf trait measurement system is not limited to shade-avoidance research and will accelerate leaf phenotyping of many mutants and screening plants by leaf phenotyping. PMID:23380664

Mumbach, Maxwell R.; Palmer, Christine M.

2013-01-01

419

Leaf P increase outpaces leaf N in an Inner Mongolia grassland over 27 years.  

PubMed

The dynamics of leaf nitrogen (N) and phosphorus (P) have been intensively explored in short-term experiments, but rarely at longer timescales. Here, we investigated leaf N : P stoichiometry over a 27-year interval in an Inner Mongolia grassland by comparing leaf N : P concentration of 2006 with that of 1979. Across 80 species, both leaf N and P increased, but the increase in leaf N lagged behind that of leaf P, leading to a significant decrease in the N : P ratio. These changes in leaf N : P stoichiometry varied among functional groups. For leaf N, grasses increased, woody species tended to increase, whereas forbs showed no change. Unlike leaf N, leaf P of grasses and forbs increased, whereas woody species showed no change. Such changes may reflect N deposition and P release induced by soil acidification over the past decades. The interannual effect of precipitation may somewhat have reduced the soil available N, leading to the more modest increase of leaf N than of leaf P. Thus, leaf N : P stoichiometry significantly responded to long-term environmental changes in this temperate steppe, but different functional groups responded differently. Our results indicate that conclusions of plant stoichiometry under short-term N fertilization should be treated with caution when extrapolating to longer timescales. PMID:25589490

Mi, Zhaorong; Huang, Yuanyuan; Gan, Huijie; Zhou, Wenjia; Flynn, Dan F B; He, Jin-Sheng

2015-01-01

420

7 CFR 28.466 - Leaf Grade 6.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is...

2010-01-01

421

7 CFR 28.465 - Leaf Grade 5.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is...

2010-01-01

422

7 CFR 28.461 - Leaf Grade 1.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is...

2012-01-01

423

7 CFR 28.463 - Leaf Grade 3.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is...

2013-01-01

424

7 CFR 28.463 - Leaf Grade 3.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is...

2012-01-01

425

7 CFR 28.462 - Leaf Grade 2.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is...

2010-01-01

426

7 CFR 28.467 - Leaf Grade 7.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which...

2012-01-01

427

7 CFR 28.467 - Leaf Grade 7.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which...

2010-01-01

428

7 CFR 28.461 - Leaf Grade 1.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is...

2013-01-01

429

7 CFR 28.464 - Leaf Grade 4.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is...

2010-01-01

430

7 CFR 28.461 - Leaf Grade 1.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is...

2011-01-01

431

7 CFR 28.467 - Leaf Grade 7.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which...

2014-01-01

432

7 CFR 28.464 - Leaf Grade 4.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is...

2014-01-01

433

7 CFR 28.465 - Leaf Grade 5.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is...

2011-01-01

434

7 CFR 28.465 - Leaf Grade 5.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is...

2013-01-01

435

7 CFR 28.466 - Leaf Grade 6.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is...

2012-01-01

436

7 CFR 28.463 - Leaf Grade 3.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is...

2010-01-01

437

7 CFR 28.461 - Leaf Grade 1.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is...

2010-01-01

438

7 CFR 28.464 - Leaf Grade 4.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is...

2013-01-01

439

7 CFR 28.466 - Leaf Grade 6.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is...

2011-01-01

440

7 CFR 28.465 - Leaf Grade 5.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is...

2014-01-01

441

7 CFR 28.466 - Leaf Grade 6.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is...

2013-01-01

442

7 CFR 28.462 - Leaf Grade 2.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is...

2013-01-01

443

7 CFR 28.463 - Leaf Grade 3.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is...

2011-01-01

444

7 CFR 28.462 - Leaf Grade 2.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is...

2012-01-01

445

7 CFR 28.466 - Leaf Grade 6.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is...

2014-01-01

446

7 CFR 28.464 - Leaf Grade 4.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is...

2012-01-01

447

7 CFR 28.467 - Leaf Grade 7.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which...

2013-01-01

448

7 CFR 28.461 - Leaf Grade 1.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is...

2014-01-01

449

7 CFR 28.462 - Leaf Grade 2.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is...

2011-01-01

450

7 CFR 28.464 - Leaf Grade 4.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is...

2011-01-01

451

7 CFR 28.462 - Leaf Grade 2.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is...

2014-01-01

452

7 CFR 28.467 - Leaf Grade 7.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which...

2011-01-01

453

7 CFR 28.463 - Leaf Grade 3.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is...

2014-01-01

454

7 CFR 28.465 - Leaf Grade 5.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture...Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is...

2012-01-01

455

Classification and quantification of leaf curvature  

PubMed Central

Various mutants of Arabidopsis thaliana deficient in polarity, cell division, and auxin response are characterized by certain types of leaf curvature. However, comparison of curvature for clarification of gene function can be difficult without a quantitative measurement of curvature. Here, a novel method for classification and quantification of leaf curvature is reported. Twenty-two mutant alleles from Arabidopsis mutants and transgenic lines deficient in leaf flatness were selected. The mutants were classified according to the direction, axis, position, and extent of leaf curvature. Based on a global measure of whole leaves and a local measure of four regions in the leaves, the curvature index (CI) was proposed to quantify the leaf curvature. The CI values accounted for the direction, axis, position, and extent of leaf curvature in all of the Arabidopsis mutants grown in growth chambers. Comparison of CI values between mutants reveals the spatial and temporal variations of leaf curvature, indicating the strength of the mutant alleles and the activities of the corresponding genes. Using the curvature indices, the extent of curvature in a complicated genetic background becomes quantitative and comparable, thus providing a useful tool for defining the genetic components of leaf development and to breed new varieties with leaf curvature desirable for the efficient capture of sunlight for photosynthesis and high yields. PMID:20400533

Liu, Zhongyuan; Jia, Liguo; Mao, Yanfei; He, Yuke

2010-01-01

456

Changes in leaf hydraulic conductance during leaf shedding in seasonally dry tropical forest  

Microsoft Academic Search

Summary • The hydraulic conductance of leaves ( k leaf ) was examined to determine whether this little understood component of the water transport pathway plays a role in governing leaf phenology of two deciduous dry forest trees ( Calycophyllum candidissimum and Rhedera trinervis ). • k leaf was monitored in parallel with stem hydraulic conductivity (K stem ) during

T. J. Brodribb; N. M. Holbrook

2003-01-01

457

ORIGINAL PAPER Leaf age and the timing of leaf abscission in two tropical dry  

E-print Network

of external factors alone (van Schaik et al. 1993; Borchert 1994; Reich 1995), suggesting that the internal. graveolens, the initiation of leaf shedding followed in rank order, the maximum leaf age of the four species and the synchrony in the timing of phenological events such as leaf fall and bud break is low

Holbrook, N. Michele

458

Analysis on leaf-stripping effect of sugarcane feeding way for centrifugal leaf-stripping machine  

Microsoft Academic Search

The feeding way of sugarcane influenced the leaf-striping effect for the centrifugal type leaf -stripping machine. In this paper, two feeding ways, fed from root and top of sugarcane stalk, were analyzed by using the method of theoretical analysis and test. The influence of structure and morphology of sugarcane leaves, the motion state of sugarcane stalks in leaf -stripping process

Mou Xiangwei; Ou Yinggang; Liu Qingting; Zeng Zhiqiang

2011-01-01

459

Leaf emergence in relation to leaf traits in temperate woody species in East-Chinese Quercus fabri forests  

NASA Astrophysics Data System (ADS)

To determine the effect of leaf traits on leaf emergence phenology, timing of leaf emergence, leaf expansion rate, durations of leaf emergence and expansion, leaf mass per area (LMA) and leaf size were investigated for 48 woody species from 25 families in two closed Chinese white oak ( Quercus fabri) forests of eastern China. Cross-species regression and phylogenetic regression were employed to examine the relationship between leaf phenology and leaf traits. Leaf area, LMA, and leaf expansion rate were found to be significantly greater in canopy trees than in understory shrubs in the oak forests. However, there was no significant difference in timing of leaf emergence and durations of leaf emergence and expansion between canopy and understory species. The large-LMA species leafed out earlier than the species with small LMA. The small-leaved species leafed out earlier than the species with large leaves, but the large-leaved species were greater in leaf expansion rate than their counterparts. Leaf expansion rate was positively correlated with leaf area and timing of leaf emergence, but no significant relationship was found between leaf size and leaf expansion period. These results suggest that large- and small-leaved species possibly employed different strategies to minimize herbivory damage, i.e. early leafing to avoid defoliator damage in small-leaved species and fast expanding and thereby shortening vulnerable time to herbivores in large-leaved species. It could be inferred that the species with small leaves and large-LMA leafed out early in the oak forests, thereby permitting less energy loss than their counterparts under the influence of frost in early spring. In general, early leaf emergence is of significance for high LMA species to increase carbon gain in temperate broad-leaved forests, but it is not related to plant height. Leaf size and leaf expansion period are not necessarily correlated.

Sun, Shucun; Jin, Dongmei; Li, Rongjin

2006-09-01

460

Curling And Inertia  

NSDL National Science Digital Library

The following resource is from Lessonopoly, which has created student activities and lesson plans to support the video series, Science of the Olympic Winter Games, created by NBC Learn and the National Science Foundation. Featuring exclusive footage from NBC Sports and contributions from Olympic athletes and NSF scientists, the series will help teach your students valuable scientific concepts. Through class discussion and a fun demonstration, students will review what they know about inertia. Students will then set up collisions with marbles and a stationary cup to explore the relationship between mass and inertia.

2010-01-01

461

Influence of leaf water status on leaf area index and leaf nitrogen concentration inversion of wheat canopy  

NASA Astrophysics Data System (ADS)

A field trial was conduct to investigate the relationship between spectral feature of winter wheat canopy and LAI as well as leaf nitrogen (N) under different status of leaf water in field situation. The objective of this study is to investigate effect of water status in plants on the accuracy of estimating leaf area index (LAI) and plant nitrogen. The new defined spectral index, IAFC = (R2224-R2054)/ (R2224+R2054), where R is the reflectance at 2224nm or 2054nm, was significantly (?=0.05) or extremely significantly (?=0.01) correlated with LAI at all the six dates for water insufficient plants, but not significantly correlated for water sufficient plants at five of the six dates and the difference of leaf water content between the water insufficient plants and water sufficient plants was only about 2% at some dates. The study provided strong evidence that leaf water has a strong masking effect on the 2000-2300nm spectral feature, which could be strongly associated with LAI and leaf N even when the leaf water content was as high as about 80% if the water was insufficient for plant growth. The results indicated that the masking effect of leaf water on the 2000-2300nm spectral feature was not only dependent on the absolute plant water content but also on the water status and that remotely sensed data in the 2000-2300nm region could be of potential in monitoring plant canopy biophysics and biochemistry in drought condition.

Zhao, Chunjiang; Wang, Jihua; Huang, Wenjiang; Liu, Liangyun

2005-01-01

462

Colony establishment and maintenance of the eriophyid wheat curl mite Aceria tosichella for controlled transmission studies on a new virus-like pathogen.  

PubMed

High plains disease (HPD) is of serious economic concern for wheat and corn production, but little is known about the virus-like causal agent. In the field, HPD is often associated with Wheat streak mosaic virus (WSMV) and both pathogens are transmitted by the same eriophyid wheat curl mite, Aceria tosichella Keifer. The objective of this study was to develop methods for establishing and maintaining HPD-transmitting wheat curl mite colonies for their use in studies on HPD. Towards this goal, mite colonies from a mixed infection source were separated into colonies either (i). not viruliferous; (ii). only transmitting WSMV; or (iii). only transmitting HPD. Maintenance of these colonies required strictly separated incubator facilities and adaptation of mite-suitable transfer techniques to permit frequent passages of mites to healthy plants. The established colonies provided reliable sources of infective material to study the progression of HPD and/or WSMV in plants using sensitive immuno-detection assays. In conclusion, we have developed reliable methods with a poorly studied arthropod vector to examine the biology and properties of a new virus-like disease. PMID:12565164

Skare, J M; Wijkamp, I; Rezende, J; Michels, G; Rush, C; Scholthof, K-B G; Scholthof, H B

2003-03-01

463

"Breath figures" on leaf surfaces-formation and effects of microscopic leaf wetness.  

PubMed

"Microscopic leaf wetness" means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 ?m, microscopic leaf wetness is about two orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the type and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g., ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past. PMID:24167510

Burkhardt, Juergen; Hunsche, Mauricio

2013-01-01

464

“Breath figures” on leaf surfaces—formation and effects of microscopic leaf wetness  

PubMed Central

“Microscopic leaf wetness” means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 ?m, microscopic leaf wetness is about two orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the type and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g., ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past. PMID:24167510

Burkhardt, Juergen; Hunsche, Mauricio

2013-01-01

465

LSD: a leaf senescence database  

PubMed Central

By broad literature survey, we have developed a leaf senescence database (LSD, http://www.eplantsenescence.org/) that contains a total of 1145 senescence associated genes (SAGs) from 21 species. These SAGs were retrieved based on genetic, genomic, proteomic, physiological or other experimental evidence, and were classified into different categories according to their functions in leaf senescence or morphological phenotypes when mutated. We made extensive annotations for these SAGs by both manual and computational approaches, and users can either browse or search the database to obtain information including literatures, mutants, phenotypes, expression profiles, miRNA interactions, orthologs in other plants and cross links to other databases. We have also integrated a bioinformatics analysis platform WebLab into LSD, which allows users to perform extensive sequence analysis of their interested SAGs. The SAG sequences in LSD can also be downloaded readily for bulk analysis. We believe that the LSD contains the largest number of SAGs to date and represents the most comprehensive and informative plant senescence-related database, which would facilitate the systems biology research and comparative studies on plant aging. PMID:21097471

Liu, Xiaochuan; Li, Zhonghai; Jiang, Zhiqiang; Zhao, Yi; Peng, Jinying; Jin, Jinpu; Guo, Hongwei; Luo, Jingchu

2011-01-01

466

Leaf Histology--Two Modern Methods.  

ERIC Educational Resources Information Center

Two methods for examining leaf structure are presented; both methods involve use of "superglue." The first method uses the glue to form a thin, permanent, direct replica of a leaf surface on a microscope slide. The second method uses the glue to examine the three-dimensional structure of spongy mesophyll. (JN)

Freeman, H. E.

1984-01-01

467

7 CFR 29.3035 - Leaf structure.  

Code of Federal Regulations, 2010 CFR

...u.s. Type 31 and Foreign Type 93) § 29.3035 Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements of quality.) [24 FR 8771, Oct. 29, 1959. Redesignated at 49 FR 16758, Apr. 20,...

2010-01-01

468

7 CFR 29.1030 - Leaf structure.  

Code of Federal Regulations, 2010 CFR

...11, 12, 13, 14 and Foreign Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality Chart.) [42 FR 21092, Apr. 25, 1977. Redesignated at 49 FR 16755, Apr. 20, 1984,...

2010-01-01

469

7 CFR 29.1030 - Leaf structure.  

Code of Federal Regulations, 2013 CFR

...11, 12, 13, 14 and Foreign Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality Chart.) [42 FR 21092, Apr. 25, 1977. Redesignated at 49 FR 16755, Apr. 20, 1984,...

2013-01-01

470

7 CFR 29.2530 - Leaf structure.  

Code of Federal Regulations, 2012 CFR

...Types 22, 23, and Foreign Type 96) § 29.2530 Leaf structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2601.) [37 FR 13626, July 12, 1972. Redesignated at 49 FR 16757, Apr. 20,...

2012-01-01

471

7 CFR 29.3527 - Leaf structure.  

Code of Federal Regulations, 2012 CFR

...Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality, § 29.3586.) [30 FR 9207, July 23, 1965. Redesignated at 49 FR 16759, Apr. 20,...

2012-01-01

472

7 CFR 29.3035 - Leaf structure.  

Code of Federal Regulations, 2014 CFR

...u.s. Type 31 and Foreign Type 93) § 29.3035 Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements of quality.) [24 FR 8771, Oct. 29, 1959. Redesignated at 49 FR 16758, Apr. 20,...

2014-01-01

473

7 CFR 29.3035 - Leaf structure.  

Code of Federal Regulations, 2013 CFR

...u.s. Type 31 and Foreign Type 93) § 29.3035 Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements of quality.) [24 FR 8771, Oct. 29, 1959. Redesignated at 49 FR 16758, Apr. 20,...

2013-01-01

474

7 CFR 29.3035 - Leaf structure.  

Code of Federal Regulations, 2011 CFR

...u.s. Type 31 and Foreign Type 93) § 29.3035 Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements of quality.) [24 FR 8771, Oct. 29, 1959. Redesignated at 49 FR 16758, Apr. 20,...

2011-01-01

475

7 CFR 29.3527 - Leaf structure.  

Code of Federal Regulations, 2013 CFR

...Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality, § 29.3586.) [30 FR 9207, July 23, 1965. Redesignated at 49 FR 16759, Apr. 20,...

2013-01-01

476

7 CFR 29.2530 - Leaf structure.  

Code of Federal Regulations, 2014 CFR

...Types 22, 23, and Foreign Type 96) § 29.2530 Leaf structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2601.) [37 FR 13626, July 12, 1972. Redesignated at 49 FR 16757, Apr. 20,...

2014-01-01

477

7 CFR 29.2530 - Leaf structure.  

Code of Federal Regulations, 2013 CFR

...Types 22, 23, and Foreign Type 96) § 29.2530 Leaf structure. The cell development of a leaf as indicated by its porosity. (See chart, § 29.2601.) [37 FR 13626, July 12, 1972. Redesignated at 49 FR 16757, Apr. 20,...

2013-01-01

478

7 CFR 29.1030 - Leaf structure.  

Code of Federal Regulations, 2011 CFR

...11, 12, 13, 14 and Foreign Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality Chart.) [42 FR 21092, Apr. 25, 1977. Redesignated at 49 FR 16755, Apr. 20, 1984,...

2011-01-01

479

7 CFR 29.1030 - Leaf structure.  

Code of Federal Regulations, 2014 CFR

...11, 12, 13, 14 and Foreign Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality Chart.) [42 FR 21092, Apr. 25, 1977. Redesignated at 49 FR 16755, Apr. 20, 1984,...

2014-01-01

480

7 CFR 29.3527 - Leaf structure.  

Code of Federal Regulations, 2011 CFR

...Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality, § 29.3586.) [30 FR 9207, July 23, 1965. Redesignated at 49 FR 16759, Apr. 20,...

2011-01-01

481

7 CFR 29.1030 - Leaf structure.  

Code of Federal Regulations, 2012 CFR

...11, 12, 13, 14 and Foreign Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality Chart.) [42 FR 21092, Apr. 25, 1977. Redesignated at 49 FR 16755, Apr. 20, 1984,...

2012-01-01

482

7 CFR 29.3035 - Leaf structure.  

Code of Federal Regulations, 2012 CFR

...u.s. Type 31 and Foreign Type 93) § 29.3035 Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements of quality.) [24 FR 8771, Oct. 29, 1959. Redesignated at 49 FR 16758, Apr. 20,...

2012-01-01

483

7 CFR 29.3527 - Leaf structure.  

Code of Federal Regulations, 2014 CFR

...Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See Elements of Quality, § 29.3586.) [30 FR 9207, July 23, 1965. Redesignated at 49 FR 16759, Apr. 20,...

2014-01-01

484

The red edge of plant leaf reflectance  

Microsoft Academic Search

The red edge is the sharp change in leaf reflectance between 680 and 750 nm and has been measured on leaves of a variety of species by first derivative reflectance spectrophotometry. A parameter ?re was defined as the wavelength of maximum slope and found to be dependent on chlorophyll concentration (p<0.001), with additional effects of species, developmental stage, leaf layering

D. N. H. Horler; M. Dockray; J. Barber

1983-01-01

485

EFFECTS OF DEOXYNIVALENOL ON BARLEY LEAF PIGMENTATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

As a first step in characterizing the role deoxynivalenol (DON) plays in pathogenesis of Fusarium graminearum in leaf and head tissues, we treated detached barley leaf tissues with DON and examined them daily for signs of injury or other alterations. As shown here, DON had pronounced and unexpected ...

486

7 CFR 29.1029 - Leaf scrap.  

Code of Federal Regulations, 2011 CFR

... Agriculture 2 2011-01-01 2011-01-01 false Leaf scrap. 29.1029 Section 29.1029 Agriculture Regulations...Types 11, 12, 13, 14 and Foreign Type 92) § 29.1029 Leaf scrap. A byproduct of stemmed and unstemmed tobacco....

2011-01-01

487

7 CFR 29.1029 - Leaf scrap.  

Code of Federal Regulations, 2010 CFR

... Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.1029 Section 29.1029 Agriculture Regulations...Types 11, 12, 13, 14 and Foreign Type 92) § 29.1029 Leaf scrap. A byproduct of stemmed and unstemmed tobacco....

2010-01-01

488

7 CFR 29.1029 - Leaf scrap.  

Code of Federal Regulations, 2012 CFR

... Agriculture 2 2012-01-01 2012-01-01 false Leaf scrap. 29.1029 Section 29.1029 Agriculture Regulations...Types 11, 12, 13, 14 and Foreign Type 92) § 29.1029 Leaf scrap. A byproduct of stemmed and unstemmed tobacco....

2012-01-01

489

7 CFR 29.1029 - Leaf scrap.  

Code of Federal Regulations, 2013 CFR

... Agriculture 2 2013-01-01 2013-01-01 false Leaf scrap. 29.1029 Section 29.1029 Agriculture Regulations...Types 11, 12, 13, 14 and Foreign Type 92) § 29.1029 Leaf scrap. A byproduct of stemmed and unstemmed tobacco....

2013-01-01

490

7 CFR 29.1029 - Leaf scrap.  

Code of Federal Regulations, 2014 CFR

... Agriculture 2 2014-01-01 2014-01-01 false Leaf scrap. 29.1029 Section 29.1029 Agriculture Regulations...Types 11, 12, 13, 14 and Foreign Type 92) § 29.1029 Leaf scrap. A byproduct of stemmed and unstemmed tobacco....

2014-01-01

491

Global patterns of leaf mechanical properties.  

PubMed

Leaf mechanical properties strongly influence leaf lifespan, plant-herbivore interactions, litter decomposition and nutrient cycling, but global patterns in their interspecific variation and underlying mechanisms remain poorly understood. We synthesize data across the three major measurement methods, permitting the first global analyses of leaf mechanics and associated traits, for 2819 species from 90 sites worldwide. Key measures of leaf mechanical resistance varied c. 500-800-fold among species. Contrary to a long-standing hypothesis, tropical leaves were not mechanically more resistant than temperate leaves. Leaf mechanical resistance was modestly related to rainfall and local light environment. By partitioning leaf mechanical resistance into three different components we discovered that toughness per density contributed a surprisingly large fraction to variation in mechanical resistance, larger than the fractions contributed by lamina thickness and tissue density. Higher toughness per density was associated with long leaf lifespan especially in forest understory. Seldom appreciated in the past, toughness per density is a key factor in leaf mechanical resistance, which itself influences plant-animal interactions and ecosystem functions across the globe. PMID:21265976

Onoda, Yusuke; Westoby, Mark; Adler, Peter B; Choong, Amy M F; Clissold, Fiona J; Cornelissen, Johannes H C; Díaz, Sandra; Dominy, Nathaniel J; Elgart, Alison; Enrico, Lucas; Fine, Paul V A; Howard, Jerome J; Jalili, Adel; Kitajima, Kaoru; Kurokawa, Hiroko; McArthur, Clare; Lucas, Peter W; Markesteijn, Lars; Pérez-Harguindeguy, Natalia; Poorter, Lourens; Richards, Lora; Santiago, Louis S; Sosinski, Enio E; Van Bael, Sunshine A; Warton, David I; Wright, Ian J; Wright, S Joseph; Yamashita, Nayuta

2011-03-01

492

Inferring climate from angiosperm leaf venation networks.  

PubMed

Leaf venation networks provide an integrative linkage between plant form, function and climate niche, because leaf water transport underlies variation in plant performance. Here, we develop theory based on leaf physiology that uses community-mean vein density to predict growing season temperature and atmospheric CO2 concentration. The key assumption is that leaf water supply is matched to water demand in the local environment. We test model predictions using leaves from 17 temperate and tropical sites that span broad climatic gradients. We find quantitative agreement between predicted and observed climate values. We also highlight additional leaf traits that may improve predictions. Our study provides a novel approach for understanding the functional linkages between functional traits and climate that may improve the reconstruction of paleoclimate from fossil assemblages. PMID:24725225

Blonder, Benjamin; Enquist, Brian J

2014-10-01

493

Changes in Leaf Trichomes and Epicuticular Flavonoids during Leaf Development in Three Birch Taxa  

PubMed Central

• Background and Aims Changes in number of trichomes and in composition and concentrations of their exudates throughout leaf development may have important consequences for plant adaptation to abiotic and biotic factors. In the present study, seasonal changes in leaf trichomes and epicuticular flavonoid aglycones in three Finnish birch taxa (Betula pendula, B. pubescens ssp. pubescens, and B. pubescens ssp. czerepanovii) were followed. • Methods Trichome number and ultrastructure were studied by means of light, scanning and transmission electron microscopy, while flavonoid aglycones in ethanolic leaf surface extracts were analysed by high-pressure liquid chromatography. • Key Results Density of both glandular and non-glandular trichomes decreased drastically with leaf expansion while the total number of trichomes per leaf remained constant, indicating that the final number of trichomes is established early in leaf development. Cells of glandular trichomes differentiate before those of the epidermis and produce secreted material only during the relatively short period (around 1–2 weeks) of leaf unfolding and expansion. In fully expanded leaves, glandular trichomes appeared to be at the post-secretory phase and function mainly as storage organs; they contained lipid droplets and osmiophilic material (probably phenolics). Concentrations (mg g?1 d. wt) of surface flavonoids decreased with leaf age in all taxa. However, the changes in total amount (µg per leaf) of flavonoids during leaf development were taxon-specific: no changes in B. pubescens ssp. czerepanovii, increase in B. pendula and in B. pubescens ssp. pubescens followed by the decline in the latter taxon. Concentrations of most of the individual leaf surface flavonoids correlated positively with the density of glandular trichomes within species, suggesting the participation of glandular trichomes in production of surface flavonoids. • Conclusions Rapid decline in the density of leaf trichomes and in the concentrations of flavonoid aglycones with leaf age suggests that the functional role of trichomes is likely to be most important at the early stages of birch leaf development. PMID:15238348

VALKAMA, ELENA; SALMINEN, JUHA-PEKKA; KORICHEVA, JULIA; PIHLAJA, KALEVI

2004-01-01

494

Specific leaf area and leaf nitrogen concentration in annual and perennial grass species growing in Mediterranean old-fields  

Microsoft Academic Search

Specific leaf area (the ratio of leaf area to leaf dry mass) and leaf nitrogen concentration were measured on ten annual\\u000a and nine perennial grass species growing in two old-fields of southern France, under a sub-humid Mediterranean climate. Specific\\u000a leaf area (SLA) was found to be significantly higher in annuals than in perennials, but leaf nitrogen concentration expressed\\u000a on a

E. Garnier; P. Cordonnier; J.-L. Guillerm; L. Sonié

1997-01-01

495

LEAF-NODULE SYMBIOSIS I.  

PubMed Central

Centifanto, Ysolina M. (University of Florida, Gainesville), and Warren S. Silver. Leafnodule symbiosis. I. Endophyte of Psychotria bacteriophila. J. Bacteriol. 88:776–781. 1964.—The leaf-nodule endophyte of Psychotria bacteriophila has been repeatedly isolated in pure culture from germinating seedlings and young leaves on a nitrogen-free mineral agar. Its morphological, serological, and cultural characteristics place it within the Klebsiella-Aerobacter group. The endophyte has been provisionally named Klebsiella rubiacearum. Pure cultures fix N2 under anaerobic conditions with good efficiency (4.54 ?g of N fixed/mg of glucose utilized in 3 days). Nitrogen fixation by pure cultures is intimately related to pyruvate and hydrogen metabolism. Images PMID:14208518

Centifanto, Ysolina M.; Silver, Warren S.

1964-01-01

496

A model for leaf initiation  

PubMed Central

A biophysical model is proposed for how leaf primordia are positioned on the shoot apical
meristem in both spiral and whorl phyllotaxes. Primordia are initiated by signals that propagate
in the epidermis in both azimuthal directions away from the cotyledons or the most recently
specified primordia. The signals are linear waves as inferred from the spatial periodicity of the
divergence angle and a temporal periodicity. The periods of the waves, which represent actively
transported auxin, are much smaller than the plastochron interval. Where oppositely directed
waves meet at one or more angular positions on the periphery of the generative circle, auxin
concentration builds and as in most models this stimulates local movement of auxin to
underlying cells, where it promotes polarized cell division and expansion. For higher order
spirals the wave model requires asymmetric function of auxin transport; that is, opposite wave
speeds differ. An algorithm for determination of the angular positions of leaves in common leaf
phyllotaxic configurations is proposed. The number of turns in a pattern repeat, number of leaves
per level and per pattern repeat, and divergence angle are related to speed of auxin transport and
radius of the generative circle. The rule for composition of Fibonacci or Lucas numbers
associated with some phyllotaxes is discussed. A subcellular model suggests how the shoot
meristem might specify either symmetric or asymmetric transport of auxin away from the
forming primordia that produce it. Biological tests that could make or break the mathematical
and molecular hypotheses are proposed. PMID:22212121

Abraham-Shrauner, Barbara; Pickard, Barbara G

2011-01-01

497

Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?  

PubMed

During plant-transpiration, water molecules having the lighter stable isotopes of oxygen and hydrogen evaporate and diffuse at a faster rate through the stomata than molecules having the heavier isotopes, which cause isotopic enrichment of leaf water. Although previous models have assumed that leaf water is well-mixed and isotopically uniform, non-uniform stomatal closure, promoting different enrichments between cells, and different pools of water within leaves, due to morpho-physiological traits, might lead to inaccuracies in isotopic models predicting leaf water enrichment. We evaluate the role of leaf morpho-physiological traits on leaf water isotopic enrichment in woody species occurring in a coastal vegetation of Brazil known as restinga. Hydrogen and oxygen stable isotope values of soil, plant stem and leaf water and leaf traits were measured in six species from restinga vegetation during a drought and a wet period. Leaf water isotopic enrichment relative to stem water was more homogeneous among species during the drought in contrast to the wet period suggesting convergent responses to deal to temporal heterogeneity in water availability. Average leaf water isotopic enrichment relative to stem water during the drought period was highly correlated with relative apoplastic water content. We discuss this observation in the context of current models of leaf water isotopic enrichment as a function of the Péclet effect. We suggest that future studies should include relative apoplastic water content in isotopic models. PMID:24068091

Rosado, Bruno H P; De Mattos, Eduardo A; Sternberg, Leonel Da S L

2013-09-01

498

Substitution of conserved cysteine residues in wheat streak mosaic virus HC-Pro abolishes virus transmission by the wheat curl mite.  

PubMed

Substitutions in the amino-proximal region of wheat streak mosaic virus (WSMV) HC-Pro were evaluated for effects on transmission by the wheat curl mite (Aceria tosichella Keifer). Alanine substitution at cysteine residues 16, 46 and 49 abolished vector transmission. Although alanine substitution at Cys(20) had no effect, substitution with arginine reduced vector transmission efficiency. Random substitutions at other positions (Lys(7) to Asn, Asn(19) to Ile, and Arg(45) to Lys) did not affect vector transmission. These results suggest that a zinc-finger-like motif (His(13)-X2-Cys(16)-X29-Cys(46)-X2-Cys(49)) in WSMV HC-Pro is essential for vector transmission. PMID:17680324

Young, B A; Hein, G L; French, R; Stenger, D C

2007-01-01

499

Evaluation of Methane from Sisal Leaf Residue and Palash Leaf Litter  

NASA Astrophysics Data System (ADS)

The aim of this study is to evaluate methane production from sisal leaf residue and palash leaf litter mixed with different bulky materials such as vegetable market waste, hostel kitchen waste and digested biogas slurry in a laboratory scale anaerobic reactor. The mixture was prepared with 1:1 proportion. Maximum methane content of 320 ml/day was observed in the case of sisal leaf residue mixed with vegetable market waste as the feed. Methane content was minimum (47 ml/day), when palash leaf litter was used as feed. This was due to the increased content of lignin and polyphenol in the feedstock which were of complex structure and did not get degraded directly by microorganisms. Sisal leaf residue mixtures also showed highest content of volatile fatty acids (VFAs) as compared to palash leaf litter mixtures. It was observed that VFA concentration in the digester first increased, reached maximum (when pH was minimum) and then decreased.

Arisutha, S.; Baredar, P.; Deshpande, D. M.; Suresh, S.

2014-12-01

500

Calibration of the Minolta SPAD502 leaf chlorophyll meter  

Microsoft Academic Search

Use of leaf meters to provide an instantaneous assessment of leaf chlorophyll has become common, but calibration of meter output into direct units of leaf chlorophyll concentration has been difficult and an understanding of the relationship between these two parameters has remained elusive. We examined the correlation of soybean (Glycine max) and maize (Zea mays L.) leaf chlorophyll concentration, as

John Markwell; John C. Osterman; Jennifer L. Mitchell

1995-01-01