Sample records for squash leaf curl

  1. Association of a recombinant Cotton leaf curl Bangalore virus with yellow vein and leaf curl disease of okra in India.

    PubMed

    Venkataravanappa, V; Lakshminarayana Reddy, C N; Devaraju, A; Jalali, Salil; Krishna Reddy, M

    2013-09-01

    A begomovirus isolate (OY136A) collected from okra plants showing upward leaf curling, vein clearing, vein thickening and yellowing symptoms from Bangalore rural district, Karnataka, India was characterized. The sequence comparisons revealed that, this virus isolate share highest nucleotide identity with isolates of Cotton leaf curl Bangalore virus (CLCuBV) (AY705380) (92.8 %) and Okra enation leaf curl virus (81.1-86.2 %). This is well supported by phylogentic analysis showing, close clustering of the virus isolate with CLCuBV. With this data, based on the current taxonomic criteria for the genus Begomovirus, the present virus isolate is classified as a new strain of CLCuBV, for which CLCuBV-[India: Bangalore: okra: 2006] additional descriptor is proposed. The betasatellite (KC608158) associated with the virus is having more than 95 % sequence similarity with the cotton leaf curl betasatellites (CLCuB) available in the GenBank.The recombination analysis suggested, emergence of this new strain of okra infecting begomovirus might have been from the exchange of genetic material between BYVMV and CLCuMuV. The virus was successfully transmitted by whitefly and grafting. The host range of the virus was shown to be very narrow and limited to two species in the family Malvaceae, okra (Abelmoschus esculentus) and hollyhock (Althaea rosea), and four in the family Solanaceae. PMID:24426275

  2. Molecular evidence for association of Tomato leaf curl New Delhi virus with leaf curl disease of papaya ( Carica papaya L.) in India

    Microsoft Academic Search

    S. K. RajA; S. K. SnehiA; M. S. KhanA; R. SinghA; A. A. KhanB

    2008-01-01

    Association ofTomato leaf curl New Delhi virus with leaf curl disease of papaya (Carica papaya L.) was detected by polymerase chain reaction using begomovirus-specific primers and confirmed by highest sequence similarities\\u000a and close phylogenetic relationships.

  3. Transreplication of a Tomato yellow leaf curl Thailand virus DNA-B and replication of a DNAß component by Tomato leaf curl Vietnam virus and Tomato yellow leaf curl Vietnam virus

    Microsoft Academic Search

    R. Blawid; D. T. Van; E. Maiss

    2008-01-01

    The genomes of two tomato-infecting begomoviruses from Vietnam were cloned and sequenced. A new variant of Tomato leaf curl Vietnam virus (ToLCVV) consisting of a DNA-A component and associated with a DNAß molecule as well as an additional begomovirus tentatively named Tomato yellow leaf curl Vietnam virus (TYLCVV) consisting also of a DNA-A component were identified. To verify if monopartite

  4. Molecular diversity of Cotton leaf curl Gezira virus isolates and their satellite DNAs associated with okra leaf curl disease in Burkina Faso

    PubMed Central

    2010-01-01

    Okra leaf curl disease (OLCD) is a major constraint on okra (Abelmoschus esculentus) production and is widespread in Africa. Using a large number of samples representative of the major growing regions in Burkina Faso (BF), we show that the disease is associated with a monopartite begomovirus and satellite DNA complexes. Twenty-three complete genomic sequences of Cotton leaf curl Gezira virus (CLCuGV) isolates associated with OLCD, sharing 95 to 99% nucleotide identity, were cloned and sequenced. Six betasatellite and four alphasatellite (DNA-1) molecules were also characterized. The six isolates of betasatellite associated with CLCuGV isolates correspond to Cotton leaf curl Gezira betasatellite (CLCuGB) (88 to 98% nucleotide identity). One isolate of alphasatellite is a variant of Cotton leaf curl Gezira alphasatellite (CLCuGA) (89% nucleotide identity), whereas the three others isolates appear to correspond to a new species of alphasatellite (CLCuGA most similar sequence present 52 to 60% nucleotide identity), provisionally named Okra leaf curl Burkina Faso alphasatellite (OLCBFA). Recombination analysis of the viruses demonstrated the interspecies recombinant origin of all CLCuGV isolates, with parents being close to Hollyhock leaf crumple virus (AY036009) and Tomato leaf curl Diana virus (AM701765). Combined with the presence of satellites DNA, these results highlight the complexity of begomoviruses associated with OLCD. PMID:20178575

  5. Identification of DNA Components Required for Induction of Cotton Leaf Curl Disease

    Microsoft Academic Search

    R. W. Briddon; S. Mansoor; I. D. Bedford; M. S. Pinner; K. Saunders; Y. Zafar; K. A. Malik; P. G. Markham

    2001-01-01

    Cotton leaf curl disease (CLCuD) is a major constraint to cotton production in Pakistan. Infectious clones of the monopartite begomovirus cotton leaf curl virus (CLCuV), associated with diseased cotton, are unable to induce typical symptoms in host plants. We have identified and isolated a single-stranded DNA molecule approximately 1350 nucleotides in length which, when coinoculated with the begomovirus to cotton,

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

    Microsoft Academic Search

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

    2006-01-01

    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)

  7. Correlation Between Whitefly (Homoptera: Aleyrodidae) Feeding Behavior and Transmission of Tomato Yellow Leaf Curl Virus

    Microsoft Academic Search

    Y. X. Jiang; Carmen de Blas; L. Barrios; A. Fereres

    2000-01-01

    The feeding behavior of the whitefly Bemisia tabaci (Gennadius) was monitored using the electrical penetration graph (EPG) technique during the transmission process of tomato yellow leaf curl geminivirus (TYLCV). The behavior of individual viruliferous whiteflies was recorded on two-leaf stage tomato test plants (Lycopersicon esculentum Mill 'Riofuego'). A total of 213 whitefly individuals was recorded on single test plants during

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

    Microsoft Academic Search

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

    2010-01-01

    Papaya leaf curl China virus (PaLCuCNV) was previously reported as a distinct begomovirus infecting papaya in southern China.\\u000a Based on molecular diagnostic survey, 13 PaLCuCNV isolates were obtained from tomato plants showing leaf curl symptoms in\\u000a Henan and Guangxi Provinces of China. Complete nucleotide sequences of 5 representative isolates (AJ558116, AJ558117, AJ704604,\\u000a FN256260, and FN297834) were determined to be 2738–2751

  9. First report of an alphasatellite associated with Okra enation leaf curl virus.

    PubMed

    Chandran, S A; Packialakshmi, R M; Subhalakshmi, K; Prakash, C; Poovannan, K; Nixon Prabu, A; Gopal, P; Usha, R

    2013-06-01

    An alphasatellite DNA associated with Okra enation leaf curl virus (OELCuV) which causes enation and leaf curling in okra (Abelmoschus esculentus) plants was characterized. The full-length DNA comprises 1,350 nucleotides and shows typical genome organization of an alphasatellite. It shows the highest nucleotide sequence identity (79.7 %) to Hollyhock yellow vein virus-associated symptomless alphasatellite (HoYVSLA). This is the first report of the association of an alphasatellite with OELCuV from India. PMID:23475199

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

    Microsoft Academic Search

    Murad Ghanim; Shai Morin; Henryk Czosnek

    2001-01-01

    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

  11. Acquisition of tomato yellow leaf curl virus by the whitefly Bemisia tabaci

    Microsoft Academic Search

    Muhammad Zeidan; Henryk Czosnek

    1991-01-01

    Tomato yellow leaf curl virus (TYLCV) genomic DNA can be detected by Southern blot analysis in nucleic acid extracted from a single whitefly. Acquisition of TYLCV by individual whiteflies in relation to the length of the access period, the virus concentration in, and the developmental stage of plant tissues was studied. The frequency of TYLCV detection increased with the length

  12. First Report of Tomato yellow leaf curl virus in Tomato in the Netherlands

    Microsoft Academic Search

    M. Botermans; J. Th. J. Verhoeven; C. C. C. Jansen; J. W. Roenhorst; C. C. M. M. Stijger; K. T. K. Pham

    2009-01-01

    Tomato yellow leaf curl virus (TYLCV) is an economically important virus with tomato (Solanum lycopersicum L.) as its main host. The virus is widely distributed in subtropical areas and is transmitted by the tobacco whitefly (Bemisia tabaci) in a persistent manner. TYLCV has a quarantine status (IIAII) in the European Union (EU directive 2000\\/29\\/EC). It was not previously recorded in

  13. Papaya is not a host for Tomato Yellow Leaf Curl Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The economic value of tomato production is threatened by tomato yellow leaf-curl virus TYLCV and its vector, the silverleaf whitefly Bemisia tabaci biotype B (Gennadius) (Hemiptera: Aleyrodidae). Use of papaya Carica papaya L. as a banker plant for a whitefly parasitoid shows promise as a whitefly m...

  14. Purification of Tomato leaf curl Bangalore virus and production of polyclonal antibodies

    Microsoft Academic Search

    Kirthi Narayanaswamy; H. S. Savithri; V. Muniyappa

    Tomato leaf curl Bangalore virus (ToLCBV) was suc- cessfully transmitted using viruliferous whiteflies ( Be- misia tabaci) to several tomato varieties and hybrids, viz. Arka vikas, Pusa ruby, Rashmi, Rakshitha and Swaraksha. Hybrid Rashmi took 100% uniform infection, which was selected for further propagation of the v irus. ToLCBV was also transmitted to Nicotiana bentha- miana; the rate of infection

  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. Single-stranded DNA of Tomato leaf curl virus accumulates in the cytoplasm of phloem cells

    Microsoft Academic Search

    M. Saif Rasheed; Luke A. Selth; Anna M. G. Koltunow; John W. Randles; M. Ali Rezaian

    2006-01-01

    Geminiviruses have been reported to replicate in, and localize to, the nuclei of host plant cells. We have investigated the tissue and intracellular distribution of the monopartite Tomato leaf curl virus (TLCV) by in situ hybridization. Contrary to the current understanding of geminiviral localization, single-stranded (ss) DNA of TLCV accumulated in the cytoplasm. TLCV ssDNA was also found in the

  17. Study of betasatellite molecule from leaf curl disease of sunn hemp (Crotalaria juncea) in India.

    PubMed

    Kumar, A; Kumar, J; Khan, Z A; Yadav, N; Sinha, V; Bhatnagar, D; Khan, J A

    2010-12-01

    Leaves of sunn hemp (Crotalaria juncea) showing geminiviral symptoms were collected from Lucknow, India during rainy season in 2008. DNA template isolated from the symptomatic leaf tissues were subjected to polymerase chain reaction (PCR) using specific primers to amplify coat protein (CP) gene of DNA-A as well as betasatellite DNA associated with the leaf curl disease. CP gene showed 97% sequence identity with that of Cotton leaf curl Burewala virus (CLCuBwV). Further, the betasatellite DNA molecule revealed sequence similarity with previously characterized betasatellite DNA of begomoviruses affecting malvaceous crops from different regions of India and Pakistan. Maximum similarity (>90%) of betasatellite DNA under study was observed with Cotton leaf curl Multan betasatellite (CLCuMB-[Pak: Mul17:08) and other betasatellite DNA from Pakistan thus confirming possible infection of C. juncea with begomovirus. A complementary sense open reading frame (ORF) ?C1 is present at nucleotide position 194-550. Sequence comparison of this ORF with other members of begomoviruses further confirmed association of a begomovirus with C. juncea. The betasatellite DNA when expressed under the control of CaMV35S promoter Nicotiana tabacum, showed leaf deformities. Our results demonstrated that a malvaceous betasatellite is adapted by a nonmalvaceous host and causes similar disease symptoms. PMID:20890652

  18. Field infection of potato by the Solanum apical leaf curling virus (SALCV)

    Microsoft Academic Search

    W. J. Hooker; L. F. Salazar; C. R. Brown

    1985-01-01

    Potato plants grown from true seed were naturally infected with the Solanum apical leaf curling virus (SALCV) at the high\\u000a jungle site near San Ramon, Peru. Tubers from these plants were greenhouse indexed. Symptoms of SALCV infected potato plants\\u000a include apical rolling, stunting, delayed emergence, weak plants, hair sprouts, and tuber dormancy. These symptoms superficially\\u000a resemble certain aspects of unusually

  19. Uniplex and duplex PCR detection of geminivirus associated with potato apical leaf curl disease in India.

    PubMed

    Jeevalatha, A; Kaundal, Priyanka; Venkatasalam, E P; Chakrabarti, S K; Singh, B P

    2013-10-01

    Apical leaf curl disease has emerged as a new disease in potato during the last decade in India due to a change in planting date and an increased whitefly population. Its incidence is on the rise threatening the cultivation of potato across the country. Hence, a PCR assay was developed for the detection of Tomato leaf curl New Delhi virus-potato (ToLCNDV-Potato) which is the causal agent of apical leaf curl disease in potato. Primers specific to the coat protein (AV1) and replicase (AC1) gene regions were designed and used for standardization of the PCR. Some of the primers (LCVCPF1/LCVCPR1, LCVREPF2/LCVREPR2, LCrep1F/LCrep2R) could detect the virus in 2.4-0.24pg of total DNA of infected plant. A duplex PCR assay was optimized with the selected coat protein gene specific primers and primers specific to potato urease gene, a housekeeping gene served as an internal check. The suitability of these primers was examined for detection of the virus in 80 potato apical leaf curl disease samples from 11 different potato growing states of India and also from micro-plants grown in tissue culture. The selected coat protein primer pair (LCVCPF1/LCVCPR1) was found to be conserved in all 80 isolates except for a few isolates, which had a single nucleotide substitution in the forward primer sequence. These substitutions did not interfere with amplification of the coat protein gene. The primers could detect the virus using a print-capture PCR assay both in the presence and absence of an internal control. These results indicate the robustness of the PCR assay for virus indexing of mother stocks in the seed production system. PMID:23711886

  20. Genetic diversity of tomato-infecting Tomato yellow leaf curl virus (TYLCV) isolates in Korea

    Microsoft Academic Search

    Sue Hoon Kim; Sung Oh; Tae-Kyun Oh; Jae Sung Park; Sei Chang Kim; Seong Hwan Kim; Young Shik Kim; Jeum Kyu Hong; Sang-Yun Sim; Kwon Seo Park; Hwan Gu Lee; Kyung Jae Kim; Chang Won Choi

    2011-01-01

    Epidemic outbreaks of Tomato yellow leaf curl virus (TYLCV) diseases occurred in greenhouse grown tomato (Solanum lycopersicum) plants of Busan (TYLCV-Bus), Boseong (TYLCV-Bos), Hwaseong (TYLCV-Hwas), Jeju Island (TYLCV-Jeju), and Nonsan (TYLCV-Nons)\\u000a in Korea during 2008–2009. Tomato disease by TYLCV has never occurred in Korea before. We synthesized the full-length genomes\\u000a of each TYLCV isolate from the tomato plants collected at

  1. Cotton leaf curl disease is associated with multiple monopartite begomoviruses supported by single DNA ß

    Microsoft Academic Search

    S. Mansoor; R. W. Briddon; S. E. Bull; I. D. Bedford; A. Bashir; M. Hussain; M. Saeed; Y. Zafar; K. A. Malik; C. Fauquet; P. G. Markham

    2003-01-01

    Summary For bipartite begomoviruses (family Geminiviridae) trans-replication of the DNA B component by the DNA A-encoded replication-associated protein (Rep) is achieved by virtue of a shared sequence, the “common region”, which contains repeated motifs (iterons) which are sequence-specific Rep binding sites and form part of the origin of replication. Recently cotton leaf curl disease (CLCuD), a major constraint to cotton

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

    Microsoft Academic Search

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

    2010-01-01

    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

  3. Mapping and introgression of a tomato yellow leaf curl virus tolerance gene, TY1

    Microsoft Academic Search

    D. Zamir; I. Ekstein-Michelson; Y. Zakay; N. Navot; M. Zeidan; M. Sarfatti; Y. Eshed; E. Harel; T. Pleban; H. van-Oss; N. Kedar; H. D. Rabinowitch; H. Czosnek

    1994-01-01

    The whitefly-transmitted tomato yellow-leaf curl gemini-virus (TYLCV) is a major pathogen of tomatoes. The wild tomato species Lycopersicon chilense, which is resistant to the virus, was crossed to the cultivated tomato, L. esculentum. The backcross-1 selfed (BC1S1) generation was inoculated and a symptomless plant was selected. This plant was analyzed using 61 molecular markers, which span the tomato genome, to

  4. Suppressor of RNA silencing encoded by Tomato yellow leaf curl virus-Israel

    Microsoft Academic Search

    Avi Zrachya; Efrat Glick; Yael Levy; Tzahi Arazi; Vitaly Citovsky; Yedidya Gafni

    2007-01-01

    The Israeli isolate of Tomato yellow leaf curl geminivirus (TYLCV-Is) is a major tomato pathogen, causing extensive crop losses both in the New and Old World. Surprisingly, however, little is known about the molecular mechanisms of TYLCV-Is interactions with tomato cells. Here, we have identified a TYLCV-Is protein, V2, which acts as a suppressor of RNA silencing and which is

  5. Evidence of local evolution of tomato-infecting begomovirus species in West Africa: characterization of tomato leaf curl Mali virus and tomato yellow leaf crumple virus from Mali

    Microsoft Academic Search

    Y.-C. Zhou; M. Noussourou; T. Kon; M. R. Rojas; H. Jiang; L.-F. Chen; K. Gamby; R. Foster; R. L. Gilbertson

    2008-01-01

    Tomato yellow leaf curl (TYLC) and tomato leaf curl (ToLC) diseases are serious constraints to tomato production in Mali and\\u000a other countries in West Africa. In 2003 and 2004, samples of tomato showing virus-like symptoms were collected during a survey\\u000a of tomato virus diseases in Mali. Three predominant symptom phenotypes were observed: (1) TYLC\\/ToLC (stunted upright growth\\u000a and upcurled leaves

  6. Selection of target sequences as well as sequence identity determine the outcome of RNAi approach for resistance against cotton leaf curl geminivirus complex

    Microsoft Academic Search

    Muhammad Mubin; Mazhar Hussain; Rob W Briddon; Shahid Mansoor

    2011-01-01

    Cotton leaf curl disease is caused by a geminivirus complex that involves multiple distinct begomoviruses and a disease-specific\\u000a DNA satellite, cotton leaf curl Multan betasatellite (CLCuMB), which is essential to induce disease symptoms. Here we have\\u000a investigated the use of RNA interference (RNAi) for obtaining resistance against one of the viruses, Cotton leaf curl Multan virus (CLCuMV), associated with the

  7. Complete nucleotide sequences of okra isolates of Cotton leaf curl Gezira virus and their associated DNA-beta from Niger.

    PubMed

    Shih, S L; Kumar, S; Tsai, W S; Lee, L M; Green, S K

    2009-01-01

    Okra (Abelmoschus esculentus) is a major crop in Niger. In the fall of 2007, okra leaf curl disease was observed in Niger and the begomovirus and DNA-beta satellite were found associated with the disease. The complete nucleotide sequences of DNA-A (FJ469626 and FJ469627) and associated DNA-beta satellites (FJ469628 and FJ469629) were determined from two samples. This is the first report of molecular characterization of okra-infecting begomovirus and their associated DNA-beta from Niger. The begomovirus and DNA-beta have been identified as Cotton leaf curl Gezira virus and Cotton leaf curl Gezira betasatellite, respectively, which are reported to also infect okra in Egypt, Mali and Sudan. PMID:19156351

  8. Regional Changes in the Sequence of Cotton Leaf Curl Multan Betasatellite

    PubMed Central

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

    2014-01-01

    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

  9. Non-chemical control of leaf curling midges and sawflies in berries and currants.

    PubMed

    Wenneker, M; Helsen, H

    2008-01-01

    The susceptibility of larvae of the leaf curling midge, Dasineura plicotrix, for entomopathogenic nematodes, predatory mites and rove beetles was studied in the laboratory. The results showed that the leaf curling midge larvae were unaffected by the nematodes Heterorhabditis bacteriophora, Steinernema carpocapsoe and S. feltiae. The predatory mite (Hypoaspis aculeifer) and the rove beetle (Atheta coriaria) were very effective in predating the larvae when continuously exposed. However, in a soil substrate the control of larvae was less successful. The vigorous burrowing behaviour of the larvae facilitates their escape from predators. This was enhanced by the formation of a cocoon consisting of soil and sand particles. The effects of the foliar fertilizer magnesium sulphate (bitter salt) were studied on gooseberry sawfty Nematus ribesii. The experiments showed that magnesium sulphate has a good residual action on eggs and neonate larvae. Also, an effect on the egg laying behaviour of the females was observed. The experiments showed that magnesium sulphate has a potential as a control agent for gooseberry sawflies. PMID:19226775

  10. Recent evolution of a novel begomovirus causing tomato leaf curl disease in the Al-Batinah region of Oman.

    PubMed

    Khan, Akhtar J; Akhtar, Sohail; Singh, Achuit K; Al-Shehi, Adel A; Al-Matrushi, Abdulrahman M; Ammara, Ume; Briddon, Rob W

    2014-03-01

    For last two decades, begomoviruses (family Geminiviridae) have been a major constraint for tomato production in Oman, particularly in the Al-Batinah region, the major agricultural area of Oman. Farms in the Al-Batinah region were surveyed during January-March and November-December in 2012 and January-February in 2013. Leaf samples of tomato plants showing typical leaf curl disease symptoms were collected and analyzed for begomoviruses. Out of fifteen begomovirus clones sequenced, seven were shown to be tomato yellow leaf curl virus strain Oman (TYLCV-OM); three, chili leaf curl virus strain Oman (ChLCV-OM); and one, tomato leaf curl Oman virus (ToLCOMV) - viruses that have previously been shown to occur in Oman. Four sequences were shown to have relatively low percent identity values to known begomoviruses, with the highest (86 %) to isolates of pepper leaf curl Lahore virus, indicating that these should be included in a new species, for which the name "Tomato leaf curl Al Batinah virus" (ToLCABV) is proposed. Although the betasatellite tomato leaf curl betasatellite (ToLCB; 7 full-length sequences isolated) was identified with some isolates of ChLCV-OM, TYLCV-OM and ToLCOMV, it was not identified in association with any of the ToLCABV isolates. Analysis of the sequences of the TYLCV-OM and ToLCOMV isolates characterized here did not show them to differ significantly from previously characterized isolates of these viruses. The three isolates of ChLCV-OM characterized were shown to have a recombination pattern distinct from earlier characterized isolates. ToLCABV was shown to have resulted from recombination between ChLCV-OM and ToLCOMV. A clone of ToLCABV was infectious by Agrobacterium-mediated inoculation to Nicotiana benthamiana and tomato, inducing symptoms typical of those seen in tomato in the field. Additionally, ToLCABV was shown to be able to interact in planta with ToLCB, resulting in a change in symptom phenotype, although the betasatellite did not appear to affect viral DNA levels. PMID:24052149

  11. Three years survey of Tomato yellow leaf curl Sardinia virus reservoir weed hosts in southern Italy.

    PubMed

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

    2007-01-01

    During the period from August 2004 to June 2006 a serious tomato yellow leaf curl epidemic caused by both Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCS) was observed in protected tomato crops in Castrovillari, Calabria Region, in a group of greenhouses where tomato is grown hydroponically. A three years survey for reservoir weed hosts of these viruses was performed during summer period in order to identify where the viruses persist during the host-free period, interesting an area covering a ray of 500 m around the group of greenhouses. About 350 samples were collected from symptomless and symptomatic plants of the following botanic families: Graminaceae, Compositeae, Solanaceae, Portulacaceae, Malvaceae, Chenopodiaceae, Amaranthaceae, Convolvulaceae, Brassicaceae, Labiatae, Plantaginaceae, Asteraceae. Any virus presence was evaluated by DAS ELISA, using a "broad-spectrum" reagent combination detecting different Begomoviruses including TYLCSV and TYLCV. A couple of synthetic oligonucleotides allowing the amplification of the whole coat protein (CP) gene 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 weeds found infected and belonging to Sonchus asper, Solanum nigrum, Datura stramonium and Cardaria draba species. Similarity analysis performed between the CP of each isolate and the TYLCSV isolate recovered within the greenhouse and responsible of the epidemic in mixed infection with a TYLCV isolate resulted in a value of 100% of identity, thus indicating that there was no variability in TYLCSV population in the surveyed area. S. asper, S. nigrum, D. stramonium and C. draba, as alternative hosts of TYLCSV and nutrient plants of the virus vector, Bemisia tabaci, were found to play an important role in virus ecology and epidemiology in the studied tomato ecosystem. No weed between those investigated has been found to be infected by TYLCV so far. To our knowledge this is the first report of S. asper and C. draba as TYLCSV hosts in natural infection. PMID:18396845

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

    Microsoft Academic Search

    Murad Ghanim; Shai Morin; Muhammad Zeidan; Henryk Czosnek

    1998-01-01

    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,

  13. Molecular characterization of tomato leaf curl China virus, infecting tomato plants in China, and functional analyses of its associated betasatellite.

    PubMed

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

    2011-05-01

    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

  14. Mathematical modeling of cotton leaf curl virus with respect to environmental factors

    PubMed Central

    Khan, Jahangir; Bashir, Zoobia; Ahmad, Aqeel; Tariq, Wajeeha; Yousaf, Anam; Gohar, Madiha

    2015-01-01

    This study mathematically correlates incidence of cotton leaf curl virus (CLCuV), environmental factors (i.e., rainfall, humidity and temperature), and silverleaf whitefly population in agricultural system of Pakistan. It has been concluded that the disease is directly linked with rainfall and humidity. The third most influential factor in defining CLCuV incidence is the vector population, which is also strictly dependent upon monthly mean temperature of Pakistan. Developed mathematical interrelation is capable of predicting disease incidence of future months. Therefore, it will help agriculturists to control disease in agricultural areas of Pakistan. It is strongly advised on the basis of current research that vector population controlling practices should be immediately applied after detecting small elevations in mean monthly temperature. PMID:26185686

  15. Effects of the mutation of selected genes of cotton leaf curl Kokhran virus on infectivity, symptoms and the maintenance of cotton leaf curl Multan betasatellite.

    PubMed

    Iqbal, Zafar; Sattar, M Naeem; Kvarnheden, Anders; Mansoor, Shahid; Briddon, Rob W

    2012-10-01

    Cotton leaf curl Kokhran virus (CLCuKoV) is a cotton-infecting monopartite begomovirus (family Geminiviridae). The effects of mutation of the coat protein (CP), V2, C2 and C4 genes of CLCuKoV on infectivity and symptoms in Nicotiana benthamiana were investigated. Each mutation introduced a premature stop codon which would lead to premature termination of translation of the gene. Mutation of the CP gene abolished infectivity. However, transient expression of the CLCuKoV CP gene under the control of the Cauliflower mosaic virus 35S promoter (35S-Ko(CP)), at the point of inoculation, led to a small number of plants in which viral DNA could be detected by PCR in tissues distal to the inoculation site. Mutations of the V2, C2 and C4 genes reduced infectivity. The V2 and C2 mutants did not induce symptoms, whereas the C4 mutation was associated with attenuated symptoms. Infections of plants with the C4 mutant were associated with viral DNA levels equivalent to the wild-type virus, whereas viral DNA levels for the V2 mutant were low, detectable by Southern blot hybridisation, and for the C2 mutant were detectable only by PCR. Significantly, transient expression of the CLCuKoV C2 gene at the point of inoculation, raised virus DNA levels in tissues distal to the inoculation site such that they could be detected by Southern hybridisation, although they remained at well below the levels seen for the wild-type virus, but reduced the infectivity of the virus. These findings are consistent with earlier mutation studies of monopartite begomoviruses and our present knowledge concerning the functions of the four genes suggesting that the CP is essential for long distance spread of the virus in plants, the C4 is involved in modulating symptoms, the C2 interferes with host defence and the V2 is involved in virus movement. The results also suggest that the V2, C2 and C4 may be pathogenicity determinants. Additionally the effects of the mutations of CLCuKoV genes on infections of the virus in the presence of its cognate betasatellite, Cotton leaf curl Multan betasatellite (CLCuMuB), were investigated. Mutation of the C4 gene had no effect on maintenance of the betasatellite, although the betasatellite enhanced symptoms. Inoculation of the C2 mutant with CLCuMuB raised the infectivity of the virus to near wild-type levels, although the numbers of plants in which the betasatellite was maintained was reduced, in comparison to wild-type virus infections with CLCuMuB, and viral DNA could not be detected by Southern hybridisation. Transient expression of the C2 gene at the point of inoculation raised virus DNA levels in tissues distal to the inoculation site but also reduced the infectivity of the virus and the numbers of plants in which the betasatellite was maintained. CLCuMuB restored the infectivity of the V2 mutant to wild-type levels but only in a small number of plants was the satellite maintained and infections were non-symptomatic. Although inoculation of the CP mutant with CLCuMuB did not restore infectivity, co-inoculation with 35S-Ko(CP) increased the number of plants in which the virus could be detected, in comparison to plants inoculated with the mutant and 35S-Ko(CP), and also resulted in two plants (out of 15 inoculated) in which the betasatellite could be detected by PCR. This indicates that the V2, C2 and almost certainly the CP are important for the maintenance of betasatellites by monopartite begomoviruses. The significance of these findings is discussed. PMID:22871297

  16. Founder effect, plant host, and recombination shape the emergent population of begomoviruses that cause the tomato yellow leaf curl disease in the Mediterranean basin.

    PubMed

    García-Andrés, Susana; Accotto, Gian Paolo; Navas-Castillo, Jesús; Moriones, Enrique

    2007-03-15

    Tomato yellow leaf curl disease (TYLCD)-associated viruses present a highly structured population in the western Mediterranean basin, depending on host, geographical region and time. About 1,900 tomato and common bean samples were analyzed from which 111 isolates were characterized genetically based on a genome sequence that comprises coding and non-coding regions. Isolates of three distinct begomoviruses previously described were found (Tomato yellow leaf curl virus, TYLCV, Tomato yellow leaf curl Sardinia virus, TYLCSV, and Tomato yellow leaf curl Málaga virus, TYLCMalV), together with a novel recombinant virus. Mixed infections were detected in single plants, rationalizing the occurrence of recombinants. Except for TYLCV-type strain, single, undifferentiated subpopulations were present for each virus type, probably the result of founder effects. Limited genetic variation was observed in genomic regions, with selection against amino acid change in coding regions. PMID:17070885

  17. Molecular dissection of Tomato leaf curl virus resistance in tomato line TY172 derived from Solanum peruvianum

    Microsoft Academic Search

    Ilana Anbinder; Moshe Reuveni; Raviv Azari; Ilan Paran; Sahadia Nahon; Haviva Shlomo; Lea Chen; Moshe Lapidot; Ilan Levin

    2009-01-01

    Tomato yellow leaf curl virus (TYLCV) is devastating to tomato (Solanum lycopersicum) crops and resistant cultivars are highly effective in controlling the disease. The breeding line TY172, originating from\\u000a Solanum peruvianum, is highly resistant to TYLCV. To map quantitative trait loci (QTLs) controlling TYLCV resistance in TY172, appropriate segregating\\u000a populations were analyzed using 69 polymorphic DNA markers spanning the entire

  18. Roles and interactions of begomoviruses and satellite DNAs associated with okra leaf curl disease in Mali, West Africa.

    PubMed

    Kon, Tatsuya; Rojas, Maria R; Abdourhamane, Issoufou K; Gilbertson, Robert L

    2009-04-01

    Okra leaf curl disease (OLCD) is a major constraint on okra (Abelmoschus esculentus) production in West Africa. Two monopartite begomoviruses (okra virus-1 and okra virus-2), a betasatellite and a DNA1 satellite are associated with OLCD in Mali. Okra virus-1 is an isolate of okra yellow crinkle virus (OYCrV), okra virus-2 is a recombinant isolate of cotton leaf curl Gezira virus (CLCuGV) and the betasatellite is a variant of cotton leaf curl Gezira betasatellite (CLCuGB). Cloned DNA of OYCrV and CLCuGV were infectious and induced leaf curl symptoms in Nicotiana benthamiana plants, but did not induce OLCD in okra. However, when these clones were individually co-inoculated with the cloned CLCuGB DNA, symptom severity and viral DNA levels were increased in N. benthamiana plants and typical OLCD symptoms were induced in okra. The CLCuGB was also replicated by, and increased symptom severity of, three monopartite tomato-infecting begomoviruses, including two from West Africa. The sequence of the DNA1 satellite was highly divergent, indicating that it represents a distinct West African lineage. DNA1 replicated autonomously, and replication required the DNA1-encoded Rep protein. Although DNA1 reduced helper begomovirus DNA levels, symptoms were not attenuated. In the presence of CLCuGB, DNA levels of the helper begomoviruses and DNA1 were substantially increased. Together, these findings establish that OLCD in Mali is caused by a complex of monopartite begomoviruses and a promiscuous betasatellite with an associated parasitic DNA1 satellite. These findings are discussed in terms of the aetiology of OLCD and the evolution of new begomovirus/satellite DNA complexes. PMID:19264648

  19. Silencing potential of viral derived RNAi constructs in Tomato leaf curl virus AC4 gene suppression in tomato

    Microsoft Academic Search

    Shelly Praveen; S. V. Ramesh; Anil K. Mishra; Vikas Koundal; Peter Palukaitis

    2010-01-01

    We investigated viral gene suppression in an infected tomato, by transforming it with RNA inhibition (RNAi) constructs derived\\u000a from same viral gene. To develop RNAi constructs, conserved sequences ranging from 21 to 200 nt of the viral target AC4 gene of various viruses causing the tomato leaf curl disease were chosen. The double-stranded (ds)RNA producing constructs\\u000a carry the sense and

  20. Genome Sequencing of the Plant Pathogen Taphrina deformans, the Causal Agent of Peach Leaf Curl

    PubMed Central

    Cissé, Ousmane H.; Almeida, João M. G. C. F.; Fonseca, Álvaro; Kumar, Ajay Anand; Salojärvi, Jarkko; Overmyer, Kirk; Hauser, Philippe M.; Pagni, Marco

    2013-01-01

    ABSTRACT Taphrina deformans is a fungus responsible for peach leaf curl, an important plant disease. It is phylogenetically assigned to the Taphrinomycotina subphylum, which includes the fission yeast and the mammalian pathogens of the genus Pneumocystis. We describe here the genome of T. deformans in the light of its dual plant-saprophytic/plant-parasitic lifestyle. The 13.3-Mb genome contains few identifiable repeated elements (ca. 1.5%) and a relatively high GC content (49.5%). A total of 5,735 protein-coding genes were identified, among which 83% share similarities with other fungi. Adaptation to the plant host seems reflected in the genome, since the genome carries genes involved in plant cell wall degradation (e.g., cellulases and cutinases), secondary metabolism, the hallmark glyoxylate cycle, detoxification, and sterol biosynthesis, as well as genes involved in the biosynthesis of plant hormones. Genes involved in lipid metabolism may play a role in its virulence. Several locus candidates for putative MAT cassettes and sex-related genes akin to those of Schizosaccharomyces pombe were identified. A mating-type-switching mechanism similar to that found in ascomycetous yeasts could be in effect. Taken together, the findings are consistent with the alternate saprophytic and parasitic-pathogenic lifestyles of T. deformans. PMID:23631913

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

    PubMed Central

    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

    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

  2. Genetic diversity of tomato-infecting Tomato yellow leaf curl virus (TYLCV) isolates in Korea.

    PubMed

    Kim, Sue Hoon; Oh, Sung; Oh, Tae-Kyun; Park, Jae Sung; Kim, Sei Chang; Kim, Seong Hwan; Kim, Young Shik; Hong, Jeum Kyu; Sim, Sang-Yun; Park, Kwon Seo; Lee, Hwan Gu; Kim, Kyung Jae; Choi, Chang Won

    2011-02-01

    Epidemic outbreaks of Tomato yellow leaf curl virus (TYLCV) diseases occurred in greenhouse grown tomato (Solanum lycopersicum) plants of Busan (TYLCV-Bus), Boseong (TYLCV-Bos), Hwaseong (TYLCV-Hwas), Jeju Island (TYLCV-Jeju), and Nonsan (TYLCV-Nons) in Korea during 2008-2009. Tomato disease by TYLCV has never occurred in Korea before. We synthesized the full-length genomes of each TYLCV isolate from the tomato plants collected at each area and determined their nucleotides (nt) sequences and deduced the amino acids of six open reading frames in the genomes. TYLCV-Bus and -Bos genomes shared higher nt identities with four Japanese isolates -Ng, -Omu, -Mis, and -Miy. On the other hand, TYLCV-Hwas, -Jeju, and -Nons genomes shared higher nt identities with five Chinese isolates TYLCV-AH1, -ZJ3, -ZJHZ12, -SH2, -Sh10, and two Japanese isolates -Han and -Tosa. On the basis of a neighbor-joining tree, five Korean TYLCV isolates were separated into three clades. TYLCV-Bus and -Bos formed the first clade, clustering with four Japanese isolates TYLCV-Mis, -Omu, -Ng, and -Miy. TYLCV-Jeju and -Nons formed the second clade, clustering with two Chinese isolates -ZJHZ212 and -Sh10. TYLCV-Hwas was clustered with two Japanese isolates -Han and -Tosa and three Chinese isolates -AH1, -ZJ3, and -SH2. Two fragments that had a potentially recombinant origin were identified using the RDP, GENECONV, BootScan, MaxChi, Chimaera, SiScan, and 3Seq methods implemented in RDP3.41. On the basis of RDP analysis, all TYLCV isolates could originated from the interspecies recombination between TYLCV-Mld[PT] isolated from Portugal as a major parent and TYLCTHV-MM isolated from Myanmar as a minor parent. PMID:20963475

  3. The spread of tomato yellow leaf curl virus from the Middle East to the world.

    PubMed

    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

    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

  4. The Merging of Two Dynasties—Identification of an African Cotton Leaf Curl Disease-Associated Begomovirus with Cotton in Pakistan

    PubMed Central

    Tahir, Muhammad Nouman; Amin, Imran; Briddon, Rob W.; Mansoor, Shahid

    2011-01-01

    Cotton leaf curl disease (CLCuD) is a severe disease of cotton that occurs in Africa and Pakistan/northwestern India. The disease is caused by begomoviruses in association with specific betasatellites that differ between Africa and Asia. During survey of symptomatic cotton in Sindh (southern Pakistan) Cotton leaf curl Gezira virus (CLCuGV), the begomovirus associated with CLCuD in Africa, was identified. However, the cognate African betasatellite (Cotton leaf curl Gezira betasatellite) was not found. Instead, two Asian betasatellites, the CLCuD-associated Cotton leaf curl Multan betasatellite (CLCuMB) and Chilli leaf curl betasatellite (ChLCB) were identified. Inoculation of the experimental plant species Nicotiana benthamiana showed that CLCuGV was competent to maintain both CLCuMB and ChLCB. Interestingly, the enations typical of CLCuD were only induced by CLCuGV in the presence of CLCuMB. Also in infections involving both CLCuMB and ChLCB the enations typical of CLCuMB were less evident. This is the first time an African begomovirus has been identified on the Indian sub-continent, highlight the growing threat of begomoviruses and particularly the threat of CLCuD causing viruses to cotton cultivation in the rest of the world. PMID:21637815

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

    PubMed

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

    2009-01-01

    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

  6. Recessive Resistance Derived from Tomato cv. Tyking-Limits Drastically the Spread of Tomato Yellow Leaf Curl Virus.

    PubMed

    Pereira-Carvalho, Rita C; Díaz-Pendón, Juan A; Fonseca, Maria Esther N; Boiteux, Leonardo S; Fernández-Muñoz, Rafael; Moriones, Enrique; Resende, Renato O

    2015-05-01

    The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread. PMID:26008699

  7. Recessive Resistance Derived from Tomato cv. Tyking-Limits Drastically the Spread of Tomato Yellow Leaf Curl Virus

    PubMed Central

    Pereira-Carvalho, Rita C.; Díaz-Pendón, Juan A.; Fonseca, Maria Esther N.; Boiteux, Leonardo S.; Fernández-Muñoz, Rafael; Moriones, Enrique; Resende, Renato O.

    2015-01-01

    The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread. PMID:26008699

  8. 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

    Galina Rubinstein; Henryk Czosnek

    1997-01-01

    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

  9. Phylogenetic Evidence for Rapid Rates of Molecular Evolution in the Single-Stranded DNA Begomovirus Tomato Yellow Leaf Curl Virus? †

    PubMed Central

    Duffy, Siobain; Holmes, Edward C.

    2008-01-01

    Geminiviruses are devastating viruses of plants that possess single-stranded DNA (ssDNA) DNA genomes. Despite the importance of this class of phytopathogen, there have been no estimates of the rate of nucleotide substitution in the geminiviruses. We report here the evolutionary rate of the tomato yellow leaf curl disease-causing viruses, an intensively studied group of monopartite begomoviruses. Sequences from GenBank, isolated from diseased plants between 1988 and 2006, were analyzed using Bayesian coalescent methods. The mean genomic substitution rate was estimated to be 2.88 × 10?4 nucleotide substitutions per site per year (subs/site/year), although this rate could be confounded by frequent recombination within Tomato yellow leaf curl virus genomes. A recombinant-free data set comprising the coat protein (V1) gene in isolation yielded a similar mean rate (4.63 × 10?4 subs/site/year), validating the order of magnitude of genomic substitution rate for protein-coding regions. The intergenic region, which is known to be more variable, was found to evolve even more rapidly, with a mean substitution rate of ?1.56 × 10?3 subs/site/year. Notably, these substitution rates, the first reported for a plant DNA virus, are in line with those estimated previously for mammalian ssDNA viruses and RNA viruses. Our results therefore suggest that the high evolutionary rate of the geminiviruses is not primarily due to frequent recombination and may explain their ability to emerge in novel hosts. PMID:17977971

  10. Water Balance, Hormone Homeostasis, and Sugar Signaling Are All Involved in Tomato Resistance to Tomato Yellow Leaf Curl Virus.

    PubMed

    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

    2014-07-01

    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

  11. Transmission of Tomato Yellow Leaf Curl Virus by Bemisia tabaci as Affected by Whitefly Sex and Biotype.

    PubMed

    Ning, Wenxi; Shi, Xiaobin; Liu, Baiming; Pan, Huipeng; Wei, Wanting; Zeng, Yang; Sun, Xinpei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Cheng, Jiaxu; Peng, Zhengke; Zhang, Youjun

    2015-01-01

    Bemisia tabaci is a serious pest of vegetables and other crops worldwide. The most damaging and predominant B. tabaci biotypes are B and Q, and both are vectors of tomato yellow leaf curl virus (TYLCV). Previous research has shown that Q outperforms B in many respects but comparative research is lacking on the ability of B and Q to transmit viruses. In the present study, we tested the hypothesis that B and Q differ in their ability to transmit TYLCV and that this difference helps explain TYLCV outbreaks. We compared the acquisition, retention, and transmission of TYLCV by B and Q females and males. We found that Q females are more efficient than Q males, B females, and B males at TYLCV acquisition and transmission. Although TYLCV acquisition and transmission tended to be greater for B females than B males, the differences were not statistically significant. Based on electrical penetration graphs determination of phloem sap ingestion parameters, females fed better than males, and Q females fed better than Q males, B females, or B males. These results are consistent with the occurrences of TYLCV outbreaks in China, which have been associated with the spread of Q rather than B. PMID:26021483

  12. New insecticides for management of tomato yellow leaf curl, a virus vectored by the silverleaf whitefly, Bemisia tabaci.

    PubMed

    Smith, H A; Giurcanu, M C

    2014-01-01

    Greenhouse studies using a randomized complete block design were carried out to evaluate the effect of six insecticides on transmission of Tomato yellow leaf curl virus (TYLCV) by the silverleaf whitefly, Bemisia tabaci biotype B Gennadius (Hemiptera: Aleyrodidae) to tomato, Lycopersicon esculentum (Miller) (Solanales: Solanaceae), seedlings that were inoculated with whiteflies from a TYLCV colony in cages 3, 7, or 14 d after treatment with insecticide. The purpose was to reveal differences in residual efficacy of four materials that are nearing registration for use on tomato-cyazypyr, flupyradifurone, pyrafluquinazon, and sulfoxaflor-and to compare them with two established insecticides, pymetrozine and a zeta-cypermethrin/bifenthrin combination. Differences in efficacy were expected because these six materials represent five distinct modes of action and both contact and systemic materials. Percentage of tomato seedlings expressing virus symptoms tended to be lowest in seedlings treated with flupyradifurone. The zeta-cypermethrin/bifenthrin insecticide demonstrated comparable efficacy to flupyradifurone in some trials at 3 and 7 d after treatment inoculations, but not the 14 d after treatment inoculation. Pyrafluquinazon was not statistically different from cyazypyr or sulfoxaflor in percentage of plants with virus symptoms in any trial. Percentage virus in the cyazypyr and sulfoxaflor treatments was not statistically different in the 3 and 7 d after treatment inoculations. Among seedlings treated with insecticide, percentage with virus symptoms tended to be highest in the seedlings treated with pymetrozine. PMID:25368089

  13. Transmission of Tomato Yellow Leaf Curl Virus by Bemisia tabaci as Affected by Whitefly Sex and Biotype

    PubMed Central

    Ning, Wenxi; Shi, Xiaobin; Liu, Baiming; Pan, Huipeng; Wei, Wanting; Zeng, Yang; Sun, Xinpei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Cheng, Jiaxu; Peng, Zhengke; Zhang, Youjun

    2015-01-01

    Bemisia tabaci is a serious pest of vegetables and other crops worldwide. The most damaging and predominant B. tabaci biotypes are B and Q, and both are vectors of tomato yellow leaf curl virus (TYLCV). Previous research has shown that Q outperforms B in many respects but comparative research is lacking on the ability of B and Q to transmit viruses. In the present study, we tested the hypothesis that B and Q differ in their ability to transmit TYLCV and that this difference helps explain TYLCV outbreaks. We compared the acquisition, retention, and transmission of TYLCV by B and Q females and males. We found that Q females are more efficient than Q males, B females, and B males at TYLCV acquisition and transmission. Although TYLCV acquisition and transmission tended to be greater for B females than B males, the differences were not statistically significant. Based on electrical penetration graphs determination of phloem sap ingestion parameters, females fed better than males, and Q females fed better than Q males, B females, or B males. These results are consistent with the occurrences of TYLCV outbreaks in China, which have been associated with the spread of Q rather than B. PMID:26021483

  14. Ultraviolet-B radiation stimulates downward leaf curling in Arabidopsis thaliana.

    PubMed

    Fierro, Ana Carolina; Leroux, Olivier; De Coninck, Barbara; Cammue, Bruno P A; Marchal, Kathleen; Prinsen, Els; Van Der Straeten, Dominique; Vandenbussche, Filip

    2015-08-01

    Plants are very well adapted to growth in ultraviolet-B (UV-B) containing light. In Arabidopsis thaliana, many of these adaptations are mediated by the UV-B receptor UV RESISTANCE LOCUS 8 (UVR8). Using small amounts of supplementary UV-B light, we observed changes in the shape of rosette leaf blades. Wild type plants show more pronounced epinasty of the blade edges, while this is not the case in uvr8 mutant plants. The UVR8 effect thus mimics the effect of phytochrome (phy) B in red light. In addition, a meta-analysis of transcriptome data indicates that the UVR8 and phyB signaling pathways have over 70% of gene regulation in common. Moreover, in low levels of supplementary UV-B light, mutant analysis revealed that phyB signaling is necessary for epinasty of the blade edges. Analysis of auxin levels and the auxin signal reporter DR5::GUS suggest that the epinasty relies on altered auxin distribution, keeping auxin at the leaf blade edges in the presence of UV-B. Together, our results suggest a co-action of phyB and UVR8 signaling, with auxin as a downstream factor. PMID:25542780

  15. Fine mapping of the tomato yellow leaf curl virus resistance gene Ty-2 on chromosome 11 of tomato.

    PubMed

    Yang, Xiaohui; Caro, Myluska; Hutton, Samuel F; Scott, John W; Guo, Yanmei; Wang, Xiaoxuan; Rashid, Md Harunur; Szinay, Dora; de Jong, Hans; Visser, Richard G F; Bai, Yuling; Du, Yongchen

    2014-01-01

    Resistances to begomoviruses, including bipartite tomato mottle virus and monopartite tomato yellow leaf curl virus (TYLCV), have been introgressed to cultivated tomato (Solanum lycopersicum) from wild tomato accessions. A major gene, Ty-2 from S. habrochaites f. glabratum accession "B6013," that confers resistance to TYLCV was previously mapped to a 19-cM region on the long arm of chromosome 11. In the present study, approximately 11,000 plants were screened and nearly 157 recombination events were identified between the flanking markers C2_At1g07960 (82.5 cM, physical distance 51.387 Mb) and T0302 (89 cM, 51.878 Mb). Molecular marker analysis of recombinants and TYLCV evaluation of progeny from these recombinants localized Ty-2 to an approximately 300,000-bp interval between markers UP8 (51.344 Mb) and M1 (51.645 Mb). No recombinants were identified between TG36 and C2_At3g52090, a region of at least 115 kb, indicating severe recombination suppression in this region. Due to the small interval, fluorescence in situ hybridization analysis failed to clarify whether recombination suppression is caused by chromosomal rearrangements. Candidate genes predicted based on tomato genome annotation were analyzed by RT-PCR and virus-induced gene silencing. Results indicate that the NBS gene family present in the Ty-2 region is likely not responsible for the Ty-2-conferred resistance and that two candidate genes might play a role in the Ty-2-conferred resistance. Several markers very tightly linked to the Ty-2 locus are presented and useful for marker-assisted selection in breeding programs to introgress Ty-2 for begomovirus resistance. PMID:25076841

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

    PubMed Central

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

    2012-01-01

    Background Tomato 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 to accelerate. This has lead to the hypothesis that the two biotypes might not be equally competent vectors of TYLCV. Methodology/Principal Findings The infection frequency of TYLCV in the field-collected B. tabaci populations was investigated, the acquisition and transmission capability of TYLCV by B and Q biotypes were compared under the laboratory conditions. Analysis of B. tabaci populations from 55 field sites revealed the existence of 12 B and 43 Q biotypes across 18 provinces in China. The acquisition and transmission experiments showed that both B and Q biotypes can acquire and transmit the virus, however, Q biotype demonstrated superior acquisition and transmission capability than its B counterparts. Specifically, Q biotype acquired significantly more viral DNA than the B biotype, and reached the maximum viral load in a substantially shorter period of time. Although TYLCV was shown to be transmitted horizontally by both biotypes, Q biotype exhibited significantly higher viral transmission frequency than B biotype. Vertical transmission result, on the other hand, indicated that TYLCV DNA can be detected in eggs and nymphs, but not in pupae and adults of the first generation progeny. Conclusions/Significance These combined results suggested that the epidemiology of TYLCV was aided differentially by the two invasive whiteflies (B and Q biotypes) through horizontal but not vertical transmission of the virus. This is consistent with the concomitant eruption of TYLCV in tomato fields following the recent rapid invasion of Q biotype whitefly in China. PMID:22514670

  17. Silencing potential of viral derived RNAi constructs in Tomato leaf curl virus-AC4 gene suppression in tomato.

    PubMed

    Praveen, Shelly; Ramesh, S V; Mishra, Anil K; Koundal, Vikas; Palukaitis, Peter

    2010-02-01

    We investigated viral gene suppression in an infected tomato, by transforming it with RNA inhibition (RNAi) constructs derived from same viral gene. To develop RNAi constructs, conserved sequences ranging from 21 to 200 nt of the viral target AC4 gene of various viruses causing the tomato leaf curl disease were chosen. The double-stranded (ds)RNA producing constructs carry the sense and antisense portions of these sequences and are separated by different introns behind a constitutive promoter. We compared the levels of suppression of the viral target gene by transforming four different RNAi constructs with varied arm length of dsRNA. Gene silencing levels of the viral target gene were found to be directly proportional to the arm length of the dsRNA. We observed that dsRNA derived from longer arm-length constructs generating a pool of siRNAs that were more effective in targeting gene silencing. After transformation, one of the RNAi construct having a 21 nt arm-length produced aberrant phenotypes. These phenotypic anomalies may be due to unintended ('off-target') host transcript silencing. The unintended host transcript silencing showed modest reversion in the presence of the viral target gene. The findings presented here suggest that the arm length of dsRNA capable of producing a pool of diced siRNAs is more efficient in gene silencing, the effect of off-targeting siRNA is minimized in a pool, and off-targeting silencing can be minimized in the presence of target gene. PMID:19548101

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

    PubMed

    Saha, Aniruddha; Saha, Bikram; Saha, Dipanwita

    2014-05-01

    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

  19. The Tomato Yellow Leaf Curl Virus Resistance Genes Ty-1 and Ty-3 Are Allelic and Code for DFDGD-Class RNA–Dependent RNA Polymerases

    PubMed Central

    Ibrahem, Ragy M.; Kormelink, Richard; Visser, Richard G. F.; Scott, John W.; Edwards, Jeremy D.; Bai, Yuling

    2013-01-01

    Tomato Yellow Leaf Curl Virus Disease incited by Tomato yellow leaf curl virus (TYLCV) causes huge losses in tomato production worldwide and is caused by different related begomovirus species. Breeding for TYLCV resistance has been based on the introgression of multiple resistance genes originating from several wild tomato species. In this study we have fine-mapped the widely used Solanum chilense–derived Ty-1 and Ty-3 genes by screening nearly 12,000 plants for recombination events and generating recombinant inbred lines. Multiple molecular markers were developed and used in combination with disease tests to fine-map the genes to a small genomic region (approximately 70 kb). Using a Tobacco Rattle Virus–Virus Induced Gene Silencing approach, the resistance gene was identified. It is shown that Ty-1 and Ty-3 are allelic and that they code for a RNA–dependent RNA polymerase (RDR) belonging to the RDR? type, which has an atypical DFDGD motif in the catalytic domain. In contrast to the RDR? type, characterized by a catalytic DLDGD motif, no clear function has yet been described for the RDR? type, and thus the Ty-1/Ty-3 gene unveils a completely new class of resistance gene. Although speculative, the resistance mechanism of Ty-1/Ty-3 and its specificity towards TYLCV are discussed in light of the function of the related RDR? class in the amplification of the RNAi response in plants and transcriptional silencing of geminiviruses in plants. PMID:23555305

  20. 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

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

    2013-05-01

    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

  1. 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

    Noris, Emanuela; Miozzi, Laura

    2015-01-01

    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

  2. Introgression of genes for cotton leaf curl virus resistance and increased fiber strength from Gossypium stocksii into upland cotton (G. hirsutum).

    PubMed

    Nazeer, W; Ahmad, S; Mahmood, K; Tipu, A L; Mahmood, A; Zhou, B

    2014-01-01

    Cotton leaf curl virus disease is a major hurdle for successful cotton production in Pakistan. There has been considerable economic loss due to this disease during the last decade. It would be desirable to have cotton varieties resistant to this disease. We explored the possibility of transferring virus resistant genes from the wild species Gossypium stocksii into MNH-786, a cultivar of G. hirsutum. Hybridization was done under field condition at the Cotton Research Station, Multan, during 2010-11. Boll shedding was controlled by application of exogenous hormones. F1 seeds were treated with 0.03% colchicine solution for 6 h and germinated. Cytological observations at peak squaring/flowering stage showed that these plants were hexaploid, having 2n = 6x = 78 chromosomes. The F1 plants showed intermediate expression for leaf size, leaf area, petiole length, bracteole number and size, bracteole area, bracteole dentation, flower size, pedicel size, and petal number and size. Moreover it possessed high fiber strength of 54.4 g/tex, which is 54% greater than that of the check variety, i.e. MNH-786 (G. hirsutum). The F1 population did not show any symptom of CLCuVD in the field, tested by grafting with CLCuVD susceptible rootstock (var. S12). We conclude that it is possible to transfer CLCuVD resistance and high fiber strength from G. stocksii to G. hirsutum. PMID:24634169

  3. Dynamics of defense-related components in two contrasting genotypes of tomato upon infection with Tomato Leaf Curl New Delhi Virus.

    PubMed

    Sahu, Pranav Pankaj; Rai, Neeraj Kumar; Puranik, Swati; Roy, Anirban; Khan, Moinuddin; Prasad, Manoj

    2012-10-01

    Tomato leaf curl virus (ToLCV) disease is a serious threat for tomato cultivation in the tropics and subtropics. Despite serious efforts no immune commercial varieties or F(1) hybrids are available till date. In this study, the interaction between Solanum lycopersicum and ToLCV was characterized on molecular and biochemical basis. RNA silencing mediated by short interfering RNA (siRNA) and reactive oxygen species (ROS) has been proposed as central components of plant adaptation to several stresses. A comparative RNA interference study between two contrasting tomato genotypes, LA1777 (tolerant) and 15SBSB (susceptible) infected with Tomato Leaf Curl New Delhi Virus (ToLCNDV) revealed relatively higher accumulation of siRNA in the leaves of tolerant genotype. In LA1777, ToLCNDV produced chlorotic as well as necrotic areas at the inoculation sites 5-10 days post-inoculation. Caspase-9- and caspase-3-like activities were significantly increased in response to ToLCNDV infection in LA1777 at inoculated region. Activities of antioxidant enzymes involved in the detoxification of ROS were examined in both systemic and localized area of infection, and their expression level was further validated through quantitative real-time PCR of the corresponding transcripts. Expression patterns of three genes encoding pathogenesis-related proteins showed higher accumulation in tolerant genotype. Tolerance against the ToLCNDV in LA1777 can be attributed to the higher siRNA accumulation, localized cell death, altered levels of antioxidant enzymes and activation of pathogenesis-related genes at different durations of virus infection. Based on these direct and indirect evidences, we have proposed a putative mechanism for ToLCNDV tolerance in the tolerant genotype. PMID:22161255

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

    PubMed Central

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

    2013-01-01

    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

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

    PubMed Central

    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

    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

  6. Tomato yellow leaf curl virus infection of a resistant tomato line with a silenced sucrose transporter gene LeHT1 results in inhibition of growth, enhanced virus spread, and necrosis

    Microsoft Academic Search

    Assaf Eybishtz; Yuval Peretz; Dagan Sade; Rena Gorovits; Henryk Czosnek

    2010-01-01

    To identify genes involved in resistance of tomato to Tomato yellow leaf curl\\u000a virus (TYLCV), cDNA libraries from lines resistant (R) and susceptible (S) to the virus were compared. The hexose transporter LeHT1 was found to be expressed preferentially in R tomato plants. The role of LeHT1 in the establishment of TYLCV resistance was studied in R plants where LeHT1

  7. 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

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

    2007-01-01

    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

  8. Subcellular localization of V2 protein of Tomato leaf curl Java virus by using green fluorescent protein and yeast hybrid system.

    PubMed

    Sharma, Pradeep; Gaur, Rajarshi K; Ikegami, Masato

    2011-04-01

    Tomato leaf curl Java virus-A (ToLCJV-A[ID]) from Southeast Asia is a new member of the emerging group of monopartite begomoviruses that require a betasatellite component for symptom induction. Previously, we have elucidated the role of V1 ORF encoded by ToLCJV-A[ID] in cell-to-cell movement. In this study, the role of V2 (PreCP) in localization was determined. Subcellular localization of ToLCJV-A[ID] V2 in plant tissues showed that this protein is co-localized to the cell cytoplasm, perinuclear and associated with the endoplasmic reticulum network. The results obtained from deletion analysis indicate that fusion of N-terminal part of the V2, containing the nuclear export signals (NES), directed the accumulation of fluorescence towards the cell cytoplasm. Furthermore, functionality of the NES ((20)LAVKYLQLV(29)) in the N-terminal part of the V2 protein was confirmed by one-hybrid yeast system. Taken together, these results suggest that V2 enhances the coat protein-mediated nuclear export of ToLCJV-A[ID] and is consistent with the model in which V2 mediates viral DNA export from the nucleus to the plasmodesmata. PMID:20549267

  9. Prediction and characterization of Tomato leaf curl New Delhi virus (ToLCNDV) responsive novel microRNAs in Solanum lycopersicum.

    PubMed

    Pradhan, Bhubaneswar; Naqvi, Afsar Raza; Saraf, Shradha; Mukherjee, Sunil Kumar; Dey, Nrisingha

    2015-01-01

    Tomato leaf curl New Delhi virus (ToLCNDV) infects tomato (Solanum lycopersicum) plants and causes severe crop losses. As the microRNAs (miRNAs) are deregulated during stressful events, such as biotic stress, we wanted to study the effect of ToLCNDV infection on tomato miRNAs. We constructed two libraries, isolating small RNAs (sRNAs) from healthy (HT) and ToLCNDV infected (IT) tomato leaves, and sequenced the library-specific sRNAs using the next generation sequencing (NGS) approach. These data helped predict 112 mature miRNA sequences employing the miRDeep-P program. A substantial number (58) of the sequences were 24-mer in size, which was a bit surprising. Based on the calculation of precision values, 53 novel miRNAs were screened from the predicted sequences. Nineteen of these were chosen for expression analysis; a northern blot analysis showed 15 to be positive. Many of the predicted miRNAs were up-regulated following viral infection. The target genes of the miRNAs were also predicted and the expression analysis of selected transcripts showed a typical inverse relation between the accumulation of target transcripts and the abundance of corresponding miRNAs. Furthermore, the cleavage sites of the target transcripts for three novel miRNAs were mapped, confirming the correct annotation of the miRNA-targets. The sRNA deep sequencing clearly revealed that the virus modulated global miRNA expression in the host. The validated miRNAs (Tom_4; Tom_14; Tom_17; Tom_21; Tom_29; Tom_43) could be valuable tools for understanding the ToLCNDV-tomato interaction, ultimately leading to the development of a virus-resistant tomato plant. PMID:25218481

  10. Quantification and Localization of Watermelon Chlorotic Stunt Virus and Tomato Yellow Leaf Curl Virus (Geminiviridae) in Populations of Bemisia tabaci (Hemiptera, Aleyrodidae) with Differential Virus Transmission Characteristics

    PubMed Central

    Kollenberg, Mario; Winter, Stephan; Götz, Monika

    2014-01-01

    Bemisia tabaci (Gennadius) is one of the economically most damaging insects to crops in tropical and subtropical regions. Severe damage is caused by feeding and more seriously by transmitting viruses. Those of the genus begomovirus (Geminiviridae) cause the most significant crop diseases and are transmitted by B. tabaci in a persistent circulative mode, a process which is largely unknown. To analyze the translocation and to identify critical determinants for transmission, two populations of B. tabaci MEAM1 were compared for transmitting Watermelon chlorotic stunt virus (WmCSV) and Tomato yellow leaf curl virus (TYLCV). Insect populations were chosen because of their high and respectively low virus transmission efficiency to compare uptake and translocation of virus through insects. Both populations harbored Rickettsia, Hamiltonella and Wolbachia in comparable ratios indicating that endosymbionts might not contribute to the different transmission rates. Quantification by qPCR revealed that WmCSV uptake and virus concentrations in midguts and primary salivary glands were generally higher than TYLCV due to higher virus contents of the source plants. Both viruses accumulated higher in insects from the efficiently compared to the poorly transmitting population. In the latter, virus translocation into the hemolymph was delayed and virus passage was impeded with limited numbers of viruses translocated. FISH analysis confirmed these results with similar virus distribution found in excised organs of both populations. No virus accumulation was found in the midgut lumen of the poor transmitter because of a restrained virus translocation. Results suggest that the poorly transmitting population comprised insects that lacked transmission competence. Those were selected to develop a population that lacks virus transmission. Investigations with insects lacking transmission showed that virus concentrations in midguts were reduced and only negligible virus amounts were found at the primary salivary glands indicating for a missing or modified receptor responsible for virus attachment or translocation. PMID:25365330

  11. Evaluation of Bt-cotton Genotypes for Resistance to Cotton Leaf Curl Disease under High Inoculum Pressure in the Field and Using Graft Inoculation in Glasshouse

    PubMed Central

    Akhtar, Khalid Pervaiz; Hussain, Manzoor; Mahmood-Ul-Hassan; Sarwar, Muhammad; Sarwar, Nighat

    2015-01-01

    Bt-cotton germplasm, consisting of 75 genotypes was evaluated against cotton leaf curl disease (CLCuD) under high inoculum pressure in the field and using graft inoculation in glasshouse by visual symptom scoring assessments. None of the tested genotype was found disease free under both evaluation tests. Under field conditions in 2011, 3 genotypes were found resistant, 4 moderately resistant, 3 tolerant, 2 moderately susceptible and one susceptible; in 2012, 3 genotypes were tolerant, 7 moderately susceptible, 5 susceptible and 38 highly susceptible; in 2013, one was moderately susceptible and 51 were highly susceptible with varying degree of percent disease index (PDI) and severity index (SI). However, through graft evaluation in glasshouse, none of the graft inoculated plant was symptomless. All tested genotypes showed disease symptoms with SI values ranging between 5.0 and 6.0, and latent period between 12 and 14 days. Of the 75 genotypes evaluated using graft inoculation, 11 were found susceptible with SI values of 5.0 to 5.4 while remaining 64 were highly susceptible with SI values of 5.5 to 6.0. Inoculated plants of all tested genotypes exhibited severe disease symptoms within 10 days after the appearance of initial symptoms. No reduction in SI value was observed until the end of the experiment i.e., 90 days after grafting. Information generated under the present study clearly demonstrates that no sources of resistance to CLCuD are available among the tested Bt-cotton genotypes. So, a breeding programme is needed to introgress the CLCuD-resistance from other resistant sources to agronomically suitable Bt-cotton genotypes.

  12. Lemony Summer Squash Ingredients

    E-print Network

    Liskiewicz, Maciej

    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

  13. Ectopic Expression of BraYAB1-702, a Member of YABBY Gene Family in Chinese Cabbage, Causes Leaf Curling, Inhibition of Development of Shoot Apical Meristem and Flowering Stage Delaying in Arabidopsis thaliana

    PubMed Central

    Zhang, Xin-Ling; Yang, Ze-Ping; Zhang, Jing; Zhang, Lu-Gang

    2013-01-01

    YABBY gene family plays an important role in the polarity development of lateral organs. We isolated the BraYAB1-702 gene, a member of the YABBY gene family, from young leaves of Chinese cabbage line 06J45. The full-length gene has a 937 bp CDNA sequence and contains an open reading frame (ORF) of 702 bp. The subcellular localization analysis showed that the expression product of the gene was localized in the nucleus. Ectopic expression of BraYAB1-702 in Arabidopsis thaliana caused leaf curling from the adaxial epidermises to abaxial epidermises; the partial abaxialization of the adaxial epidermises of leaves; leaf trichomes and stomata numbers being significantly increased; the plants being severely stunted; the flowering stage being remarkably delayed and inhibiting the development of shoot apical meristem (SAM) with the down-regulation of the expression of SHOOT MERISTEMLESS (STM), Brevipedicellus (BP) and KNAT2 which were related to the development of shoot apical meristem. These results from the present research help to reveal the molecular mechanism of BraYAB1-702 gene in the establishment of adaxial–abaxial polarity of the lateral organs in Chinese cabbage. PMID:23863694

  14. Informally, (Squash-intro)

    E-print Network

    The ``Squash'' Type Informally, [A] = fUnit j Ag ` A ` [A] (Squash-intro) ; x : A; #1; ` t 2 C ; x rules can not express the result of completely eliminating ND. #15; (ND-memb) is here to show what (ND[ff] 2 A ; x : ND ` t[x] 2 A (ND-memb) 8 #12; Notes #15; The only irreversible rule here is (Iquot

  15. Curls of My Dreams.

    ERIC Educational Resources Information Center

    Greenman, Geri

    2001-01-01

    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)

  16. Transcriptomics of the interaction between the monopartite phloem-limited geminivirus tomato yellow leaf curl Sardinia virus and Solanum lycopersicum highlights a role for plant hormones, autophagy and plant immune system fine tuning during infection.

    PubMed

    Miozzi, Laura; Napoli, Chiara; Sardo, Luca; Accotto, Gian Paolo

    2014-01-01

    Tomato yellow leaf curl Sardinia virus (TYLCSV), a DNA virus belonging to the genus Begomovirus, causes severe losses in tomato crops. It infects only a limited number of cells in the vascular tissues, making difficult to detect changes in host gene expression linked to its presence. Here we present the first microarray study of transcriptional changes induced by the phloem-limited geminivirus TYLCSV infecting tomato, its natural host. The analysis was performed on the midrib of mature leaves, a material naturally enriched in vascular tissues. A total of 2206 genes were up-regulated and 1398 were down-regulated in infected plants, with an overrepresentation of genes involved in hormone metabolism and responses, nucleic acid metabolism, regulation of transcription, ubiquitin-proteasome pathway and autophagy among those up-regulated, and in primary and secondary metabolism, phosphorylation, transcription and methylation-dependent chromatin silencing among those down-regulated. Our analysis showed a series of responses, such as the induction of GA- and ABA-responsive genes, the activation of the autophagic process and the fine tuning of the plant immune system, observed only in TYLCSV-tomato compatible interaction so far. On the other hand, comparisons with transcriptional changes observed in other geminivirus-plant interactions highlighted common host responses consisting in the deregulation of biotic stress responsive genes, key enzymes in the ethylene biosynthesis and methylation cycle, components of the ubiquitin proteasome system and DNA polymerases II. The involvement of conserved miRNAs and of solanaceous- and tomato-specific miRNAs in geminivirus infection, investigated by integrating differential gene expression data with miRNA targeting data, is discussed. PMID:24587146

  17. Tomato yellow leaf curl Sardinia virus-resistant tomato plants expressing the multifunctional N-terminal domain of the replication-associated protein show transcriptional changes resembling stress-related responses.

    PubMed

    Lucioli, Alessandra; Berardi, Alessandra; Gatti, Francesca; Tavazza, Raffaela; Pizzichini, Daniele; Tavazza, Mario

    2014-01-01

    The N-terminal domain (amino acids 1-130) of the replication-associated protein (Rep130 ) of Tomato yellow leaf curl Sardinia virus (TYLCSV) retains the ability of full-length Rep to localize to the nucleus and to down-regulate C1 transcription when ectopically expressed in plants, both functions being required to inhibit homologous viral replication. In this study, we analysed the effect of Rep130 expression on virus resistance and the plant transcriptome in the natural and agronomically important host species of TYLCSV, Solanum lycopersicum. Tomato plants accumulating high levels of Rep130 were generated and proved to be resistant to TYLCSV. Using an in vitro assay, we showed that plant-expressed Rep130 also retains the catalytic activity of Rep, thus supporting the notion that this protein domain is fully functional. Interestingly, Rep130 -expressing tomatoes were characterized by an altered transcriptional profile resembling stress-related responses. Notably, the serine-type protease inhibitor (Ser-PI) category was over-represented among the 20 up-regulated genes. The involvement of Rep130 in the alteration of host mRNA steady-state levels was confirmed using a distinct set of virus-resistant transgenic tomato plants expressing the same TYLCSV Rep130 , but from a different, synthetic, gene. Eight genes were found to be up-regulated in both types of transgenic tomato and two encoded Ser-PIs. Four of these eight genes were also up-regulated in TYLCSV-infected wild-type tomato plants. Implications with regard to the ability of this Rep domain to interfere with viral infections and to alter the host transcriptome are discussed. PMID:23910556

  18. Transcriptomics of the Interaction between the Monopartite Phloem-Limited Geminivirus Tomato Yellow Leaf Curl Sardinia Virus and Solanum lycopersicum Highlights a Role for Plant Hormones, Autophagy and Plant Immune System Fine Tuning during Infection

    PubMed Central

    Miozzi, Laura; Napoli, Chiara; Sardo, Luca; Accotto, Gian Paolo

    2014-01-01

    Tomato yellow leaf curl Sardinia virus (TYLCSV), a DNA virus belonging to the genus Begomovirus, causes severe losses in tomato crops. It infects only a limited number of cells in the vascular tissues, making difficult to detect changes in host gene expression linked to its presence. Here we present the first microarray study of transcriptional changes induced by the phloem-limited geminivirus TYLCSV infecting tomato, its natural host. The analysis was performed on the midrib of mature leaves, a material naturally enriched in vascular tissues. A total of 2206 genes were up-regulated and 1398 were down-regulated in infected plants, with an overrepresentation of genes involved in hormone metabolism and responses, nucleic acid metabolism, regulation of transcription, ubiquitin-proteasome pathway and autophagy among those up-regulated, and in primary and secondary metabolism, phosphorylation, transcription and methylation-dependent chromatin silencing among those down-regulated. Our analysis showed a series of responses, such as the induction of GA- and ABA-responsive genes, the activation of the autophagic process and the fine tuning of the plant immune system, observed only in TYLCSV-tomato compatible interaction so far. On the other hand, comparisons with transcriptional changes observed in other geminivirus-plant interactions highlighted common host responses consisting in the deregulation of biotic stress responsive genes, key enzymes in the ethylene biosynthesis and methylation cycle, components of the ubiquitin proteasome system and DNA polymerases II. The involvement of conserved miRNAs and of solanaceous- and tomato-specific miRNAs in geminivirus infection, investigated by integrating differential gene expression data with miRNA targeting data, is discussed. PMID:24587146

  19. Faithful Squashed Entanglement

    NASA Astrophysics Data System (ADS)

    Brandão, Fernando G. S. L.; Christandl, Matthias; Yard, Jon

    2011-09-01

    Squashed entanglement is a measure for the entanglement of bipartite quantum states. In this paper we present a lower bound for squashed entanglement in terms of a distance to the set of separable states. This implies that squashed entanglement is faithful, that is, it is strictly positive if and only if the state is entangled. We derive the lower bound on squashed entanglement from a lower bound on the quantum conditional mutual information which is used to define squashed entanglement. The quantum conditional mutual information corresponds to the amount by which strong subadditivity of von Neumann entropy fails to be saturated. Our result therefore sheds light on the structure of states that almost satisfy strong subadditivity with equality. The proof is based on two recent results from quantum information theory: the operational interpretation of the quantum mutual information as the optimal rate for state redistribution and the interpretation of the regularised relative entropy of entanglement as an error exponent in hypothesis testing. The distance to the set of separable states is measured in terms of the LOCC norm, an operationally motivated norm giving the optimal probability of distinguishing two bipartite quantum states, each shared by two parties, using any protocol formed by local quantum operations and classical communication (LOCC) between the parties. A similar result for the Frobenius or Euclidean norm follows as an immediate consequence. The result has two applications in complexity theory. The first application is a quasipolynomial-time algorithm solving the weak membership problem for the set of separable states in LOCC or Euclidean norm. The second application concerns quantum Merlin-Arthur games. Here we show that multiple provers are not more powerful than a single prover when the verifier is restricted to LOCC operations thereby providing a new characterisation of the complexity class QMA.

  20. Faithful Squashed Entanglement

    E-print Network

    Fernando G. S. L. Brandao; Matthias Christandl; Jon Yard

    2012-07-20

    Squashed entanglement is a measure for the entanglement of bipartite quantum states. In this paper we present a lower bound for squashed entanglement in terms of a distance to the set of separable states. This implies that squashed entanglement is faithful, that is, strictly positive if and only if the state is entangled. We derive the bound on squashed entanglement from a bound on quantum conditional mutual information, which is used to define squashed entanglement and corresponds to the amount by which strong subadditivity of von Neumann entropy fails to be saturated. Our result therefore sheds light on the structure of states that almost satisfy strong subadditivity with equality. The proof is based on two recent results from quantum information theory: the operational interpretation of the quantum mutual information as the optimal rate for state redistribution and the interpretation of the regularised relative entropy of entanglement as an error exponent in hypothesis testing. The distance to the set of separable states is measured by the one-way LOCC norm, an operationally-motivated norm giving the optimal probability of distinguishing two bipartite quantum states, each shared by two parties, using any protocol formed by local quantum operations and one-directional classical communication between the parties. A similar result for the Frobenius or Euclidean norm follows immediately. The result has two applications in complexity theory. The first is a quasipolynomial-time algorithm solving the weak membership problem for the set of separable states in one-way LOCC or Euclidean norm. The second concerns quantum Merlin-Arthur games. Here we show that multiple provers are not more powerful than a single prover when the verifier is restricted to one-way LOCC operations thereby providing a new characterisation of the complexity class QMA.

  1. FOOD PRESERVATION SERIES Summer Squash

    E-print Network

    then be grated and used in quick bread recipes. Add thin strips or slices of summer squash to salads or soups bread. WO1051 #12;how to preserve how to prepare recipe Skillet Zucchini with Chopped Tomatoes 1 in a wok or frying pan. Add squash pieces to hot oil. Season with salt and pepper. Use soy sauce or fish

  2. Sauted Summer Squash with Oregano Ingredients

    E-print Network

    Liskiewicz, Maciej

    Sautéed Summer Squash with Oregano Ingredients: 2 teaspoons olive oil 1 onion 2 cloves garlic 2 tablespoons dried oregano 1 pound zucchini 1 pound summer squash Directions 1. Heat oil in skillet over medium

  3. NU Intramural Sports Squash Rules

    E-print Network

    Sridhar, Srinivas

    NU Intramural Sports Squash Rules GENERAL RULES: 1. All players must present their valid identification card. 2. Jewelry is not allowed to be worn by any participant during an Intramural event. Any with a band-aid. 3. GAME TIME IS FORFEIT TIME! The minimum number of players must have their Husky Cards

  4. Managing Squash Vine Borer Problems in New Hampshire

    E-print Network

    New Hampshire, University of

    most types of squash and pumpkin. Damage can be severe. Some growers confuse this insect with squash into the fruit of hard squash or pumpkin. Fruit damage generally occurs when there is a late flush of moths lay eggs. The females locate squash and pumpkin plants by smell, and lay their eggs singly

  5. SQUASH NEWFOUNDLAND INDIVIDUAL MEMBERSHIP APPLICATION 2003-2004

    E-print Network

    SQUASH NEWFOUNDLAND INDIVIDUAL MEMBERSHIP APPLICATION 2003-2004 (Valid for 12 months from receipt misuse your card. Squash Newfoundland and Labrador Inc. P. O. Box 21254 St. John's, NL, A1A 5B2 #12;SQUASH NEWFOUNDLAND MEMBERSHIP WAIVER I/We agree to abide by Squash Newfoundland regulations and enclose

  6. Influence of velocity curl on conservation laws

    E-print Network

    Zihua Weng

    2009-08-11

    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.

  7. Inhibition of serine proteinases by squash inhibitors.

    PubMed

    Otlewski, J; Zbyryt, T; Krokoszy?ska, I; Wilusz, T

    1990-07-01

    The squash inhibitors of serine proteinases have been discovered as proteins, which inhibit the catalytic activity of bovine trypsin. In this report we show, that three human enzymes of trypsin-like specificity - i.e. plasmin, plasma kallikrein and thrombin - are also inhibited by squash inhibitors. Moreover, rather strong inhibition was demonstrated for human cathepsin G. Lower association constants were found for Streptomyces griseus proteinase B (SGPB) and subtilisin BPN'. No association was detected for bovine chymotrypsin, even at millimolar concentrations of the inhibitors. Porcine pancreatic elastase showed extremely weak inhibition by squash inhibitors. Most of the enzymes examined did not exhibit a clear discrimination between P1 Arg and P1 Lys inhibitors. However, human plasma kallikrein and human thrombin formed much stronger complexes with CMTI I (P1-Arg) than with CPTI II (P1-Lys). PMID:2145863

  8. Gene silencing of Tomato Yellow Leaf Curl Virus

    Microsoft Academic Search

    Ghandi Anfoka

    The Geminiviridae family has received a great deal of attention in recent years and is becoming one of the most important and studied families\\u000a of plant viruses. Some reasons why so much effort has been dedicated to their study include the economic and social impact\\u000a of the diseases they cause (Palmer & Rybicki; 1998; Harrison & Robinson, 1999; Morales &

  9. Post-directed 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 ...

  10. Double Curl Beltrami Flow: Diamagnetic Structures

    SciTech Connect

    Mahajan, S.M. [Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States)] [Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (United States); Yoshida, Z. [Faculty of Engineering, University of Tokyo, Hongo, Tokyo 113 (Japan)] [Faculty of Engineering, University of Tokyo, Hongo, Tokyo 113 (Japan)

    1998-11-01

    It is shown that in an ideal coupled magnetofluid, the equilibrium magnetic (velocity) field is described by a two-parameter, double curl ({triangledown}{times}{triangledown}{times}) system of equations. The new system allows, among others, a novel, fully diamagnetic, pressure confining, minimum {vert_bar}B{vert_bar} configuration with velocity fields comparable (in appropriate units) to the magnetic fields. {copyright} {ital 1998} {ital The American Physical Society}

  11. H(curl) Auxiliary Mesh Preconditioning

    SciTech Connect

    Kolev, T V; Pasciak, J E; Vassilevski, P S

    2006-08-31

    This paper analyzes a two-level preconditioning scheme for H(curl) bilinear forms. The scheme utilizes an auxiliary problem on a related mesh that is more amenable for constructing optimal order multigrid methods. More specifically, we analyze the case when the auxiliary mesh only approximately covers the original domain. The latter assumption is important since it allows for easy construction of nested multilevel spaces on regular auxiliary meshes. Numerical experiments in both two and three space dimensions illustrate the optimal performance of the method.

  12. On Sloane's Generalization of NonSquashing Stacks of Boxes

    E-print Network

    Sellers, James A.

    On Sloane's Generalization of Non­Squashing Stacks of Boxes George E. Andrews and James A. Sellers and Sellers solved a certain box stacking problem related to non­ squashing partitions. These are defined. Sloane has also hinted at a generalized box stacking problem which is closely related to gener- alized

  13. The Curl of a Vector Field: Beyond the Formula

    ERIC Educational Resources Information Center

    Burch, Kimberly Jordan; Choi, Youngna

    2006-01-01

    It has been widely acknowledged that there is some discrepancy in the teaching of vector calculus in mathematics courses and other applied fields. The curl of a vector field is one topic many students can calculate without understanding its significance. In this paper, we explain the origin of the curl after presenting the standard mathematical…

  14. The physics of sliding cylinders and curling rocks

    NASA Astrophysics Data System (ADS)

    Penner, A. Raymond

    2001-03-01

    The lateral deflection of a rotating cylindrical shell sliding on one of its ends is considered and both theoretical and experimental results are presented. The coefficient of kinetic friction between a curling rock and an ice surface is then derived and compared with experiment. Current models of the motion of a curling rock are discussed and an alternate hypothesis is presented.

  15. Direct discretization of planar div-curl problems

    NASA Technical Reports Server (NTRS)

    Nicolaides, R. A.

    1989-01-01

    A control volume method is proposed for planar div-curl systems. The method is independent of potential and least squares formulations, and works directly with the div-curl system. The novelty of the technique lies in its use of a single local vector field component and two control volumes rather than the other way around. A discrete vector field theory comes quite naturally from this idea and is developed. Error estimates are proved for the method, and other ramifications investigated.

  16. On the impact of wind curls on coastal currents

    Microsoft Academic Search

    Wolfgang Fennel; Hans Ulrich Lass

    2007-01-01

    Studies of upwelling and coastally-trapped wave theory, as developed over the past thirty years, have largely neglected effects of cross-shelf variation in wind stress and the resulting wind stress curl. However, recent satellite-based observations (QuikSCAT) of global wind stress patterns show significant and persistent wind stress curls extending well offshore in some coastal regions including the Benguela System. Motivated by

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

    E-print Network

    Boyer, Edmond

    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

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

    E-print Network

    Paris-Sud XI, Université de

    Helmholtz-Hodge Decomposition on [0, 1]d by Divergence-free and Curl-free Wavelets Souleymane Kadri a practical algorithm to compute this decomposition in the context of divergence-free and curl- free wavelets satisfying suitable boundary conditions. The method requires the inversion of divergence-free and curl-free

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

    E-print Network

    Starck, Jean-Luc

    Orthogonal Helmholtz decomposition in arbitrary dimension using divergence-free and curl-free Analysis Abstract We present tensor-product divergence-free and curl-free wavelets, and define asso- ciated wavelets. We also present a modification of the algorithm by using quasi-isotropic divergence-free and curl-free

  20. Cucurbit leaf crumple virus detected in green beans in southwest Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucurbit leaf crumple virus (CuLCrV) was recently reported infecting various cucurbit crops, including squash and watermelon, in Florida. In December 2007, CuLCrV was identified for the first time in green beans in southwest Florida. Although CuLCrV has previously been reported to infect beans in ...

  1. Computation of Surface Integrals of Curl Vector Fields

    ERIC Educational Resources Information Center

    Hu, Chenglie

    2007-01-01

    This article presents a way of computing a surface integral when the vector field of the integrand is a curl field. Presented in some advanced calculus textbooks such as [1], the technique, as the author experienced, is simple and applicable. The computation is based on Stokes' theorem in 3-space calculus, and thus provides not only a means to…

  2. Covolume solutions of three dimensional div-curl equations

    NASA Technical Reports Server (NTRS)

    Nicolaides, R. A.; Wu, X.

    1995-01-01

    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.

  3. Squash Reuse via a Simplified Implementation of Register Integration

    Microsoft Academic Search

    Amir Roth; Gurindar S. Sohi

    2001-01-01

    Register integration (or simply integration) is a mechanism for the direct reuse of previously computed results. Integration uses data-dependence relationships to test for and establish reusability. In this paper, we use integration to implement squash reuse, the salvaging of instruction results that were needlessly discarded during the course of sequential recovery from a control- or data- mis-speculation. In integration, the

  4. Weed Management in No-Till Zucchini Squash

    Microsoft Academic Search

    S. Alan Walters; Bryan G. Young

    2011-01-01

    Weed control in no-tillage (NT) zucchini squash (Cucurbita pepo L.) was determined for various preemergence (PRE) herbicide combinations in herbicide-killed ‘Wheeler’ winter rye (Secale cereale L.) or bare soil. Winter rye provided 65% and 75% control of redroot pigweed (Amaranthus retroflexus L.) and smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.], respectively, in the absence of herbicides compared with no

  5. 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 (...

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

    SciTech Connect

    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

    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.

  7. Curl-Conforming Hierarchical Vector Bases for Triangles and Tetrahedra

    Microsoft Academic Search

    Roberto D. Graglia; Andrew F. Peterson; Francesco P. Andriulli

    2011-01-01

    A new family of hierarchical vector bases is pro- posed for triangles and tetrahedra. These functions span the curl-conforming reduced-gradient spaces of Nédélec. The bases are constructed from orthogonal scalar polynomials to enhance their linear independence, which is a simpler process than an orthogonalization applied to the final vector functions. Specific functions are tabulated to order 6.5. Preliminary results confirm

  8. Curling and rolling dynamics of naturally curved ribbons.

    PubMed

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

    2014-05-01

    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

  9. Hydro-Responsive Curling of the Resurrection Plant Selaginella lepidophylla

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

  10. Methyl bromide alternatives in a bell pepper–squash rotation

    Microsoft Academic Search

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

    2001-01-01

    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)].

  11. A Rotating Kaluza-Klein Black Hole with Squashed Horizons

    E-print Network

    Tower Wang

    2006-09-05

    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.

  12. CURL: A Searchable CUrricular Resources Library of Earth and Environmental Science Websites

    Microsoft Academic Search

    S. O'Connell; T. Klassen; M. Roy; M. Glynn

    2001-01-01

    A searchable web-based Curricular Resources Library (CURL) has been developed by earth and environmental science faculty from four New England schools (Dartmouth College, Connecticut College, Trinity College, and Wesleyan University) in conjunction with Wesleyan's Information Technology Services (ITS) and librarians. The site (http:\\/\\/www.wesleyan.edu\\/curl\\/) provides access to pre-selected earth and environmental science material. CURL sites are identified by faculty who provide

  13. Squashing Cubes: Automating Deformable Model Construction for Graphics Doug L. James Jernej Barbic Christopher D. Twigg (Carnegie Mellon University)

    E-print Network

    James, Doug L.

    Squashing Cubes: Automating Deformable Model Construction for Graphics Doug L. James Jernej Barbic) a flexible plastic chair; (Right) a complex swaying bridge superstructure. Introduction The vast majority models remains a tedious process for animators. Squashing Cubes (SC) automates the construction

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    Numerous 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.

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

    PubMed Central

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

    2000-01-01

    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

  16. 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...

  17. Dr Samuel Matthias Curl alias Dr Alan Carroll.

    PubMed

    Rawstron, R E

    1997-04-25

    Samuel Matthias Curl was the first medical practitioner in Tawa commencing practice there in 1855. He moved to the Rangitikei district in 1862 and practised there until 1887 when he eloped to Sydney with Annie Douglas. Besides practising medicine in New Zealand he farmed in both areas, was noted for his agricultural research and his work on several committees. In Sydney he assumed the name of Dr Alan Carroll and worked as an anthropologist and child health adviser. He died on the 17 April 1911 and left his estate in trust to establish two scientific bequests. PMID:9152358

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

    PubMed Central

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

    2009-01-01

    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

  19. Edge curling that has plagued scrolls for millenniums

    NASA Astrophysics Data System (ADS)

    Chou, Ming-Han; Shen, Wei-Chao; Wang, Yi-Ping; Hung, Sun-Hsin; Hong, Tzay-Ming; Department of Registration and Conservation, National Palace Museum Collaboration; Department of Physics, National Tsing Hua University Team

    2014-03-01

    Qi-Wa refers to the up curl on the lengths of handscrolls and hanging scrolls, which has troubled Chinese artisans and emperors for as long as the art of painting and calligraphy exists. 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 possible relevance of our study to the modern development of flexible electronic paper.

  20. Resonance Frequencies of Curling Probe in Plasma: Surface Wave Analysis

    NASA Astrophysics Data System (ADS)

    Arshadi, Ali; Brinkmann, Ralf Peter

    2014-10-01

    Electron density is a crucial characteristic in reactive plasma sources determining the quality of material processing like etching. A recently invented plasma diagnostic probe called curling probe resonates in distinctive frequencies when it is embedded in the wall of the plasma reactor. The excited frequencies are studied for various electron densities. It has been demonstrated that the high-frequency (HF) volume wave resonances and the low-frequency (LF) surface wave (SW) resonances are predictable considering the wave propagation in plasma when it is diffracted on the curling probe. We consider the three dimensional diffraction of incident plane wave by a slot in an infinitely thin perfectly conducting screen located between dielectric and sheath. Our computations for LF resonances were published recently. The results are in a very good agreement with the FDTD analysis. Here it is demonstrated that the LF resonances are based on the SW propagation. We compare our result with the one comes from SW analysis and we prove that the LF resonances are not dependent on the length of probe. We generalized our study to be able to investigate the effect of sheath thickness and electron-neutral collisions which is not possible in the other theoretical and computational methods.

  1. Curling Edges: A Problem that Has Plagued Scrolls for Millennia

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  2. NotePrediction of early age curling in thin concrete topping over wood floor systems

    Microsoft Academic Search

    Peter Lee; Ying H. Chui; Ian Smith; Gerry Pernica

    2002-01-01

    This paper presents finite element simulations of curling of vnreinforced conmle topping Iaid over wood floor systems. The finite analysis consists of two parts* The first part calculates the relativc moisture dis~bution with respect to the age of the concrete. while thc second determines the lopping curling deformation based on rnoduhs of elasticity, density, and shrinkage of the concrete. With

  3. Out with the Sit-Up, in with the Curl-Up!

    ERIC Educational Resources Information Center

    MacFarlane, Pamela A.

    1993-01-01

    Explains why physical education teachers should discourage full sit-ups and describes the Robertson Modified Curl-Up Test as a recommended alternative test of abdominal muscular strength. Curl-up test administration guidelines are included with some preliminary norms from adult groups. (SM)

  4. Sparsity optimized high order finite element functions for H(curl) on tetrahedra

    E-print Network

    Schneider, Carsten

    Sparsity optimized high order finite element functions for H(curl) on tetrahedra Sven Beuchler space H(curl) in 3 dimensions. We introduce a set of hierarchic basis functions on tetrahedra of the sparsity result on general tetrahedra defined in terms of their barycentric coordinates is carried out

  5. 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...

  6. Transgenic approaches for the Control of Tomato Yellow Leaf Curl Virus

    Microsoft Academic Search

    JANE E. POLSTON; Ernest Hiebert

    Management of TYLCV and other begomoviruses is very difficult and expensive. The least expensive and most practical control\\u000a of TYLCV and many other begomoviruses is the use of resistant cultivars. Begomovirus-resistant tomato cultivars would greatly\\u000a reduce the use of insecticides for whitefly control, which would reduce production costs and chemical contamination of the\\u000a environment. Conventional breeding of TYLCV-resistant tomato lines

  7. Genetic Variability of Natural Populations of Cotton Leaf Curl Geminivirus, a Single-Stranded DNA Virus

    Microsoft Academic Search

    Ana I. Sanz; Aurora Fraile; Jesus M. Gallego; Jose M. Malpica; Fernando García-Arenal

    1999-01-01

    .   Reports on the genetic variability and evolution of natural populations of DNA viruses are scarce in comparison with the\\u000a abundant information on the variability of RNA viruses. Geminiviruses are plant viruses with circular ssDNA genomes that are\\u000a replicated by the host plant DNA polymerases. Whitefly-transmitted geminiviruses (WTG) are the agents of important diseases\\u000a of crop plants and best exemplify

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

    PubMed Central

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

    2013-01-01

    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

  9. Flat acoustic lens by acoustic grating with curled slits

    NASA Astrophysics Data System (ADS)

    Peng, Pai; Xiao, Bingmu; Wu, Ying

    2014-10-01

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry-Perot resonance.

  10. Leaf Activities.

    ERIC Educational Resources Information Center

    Mingie, Walter

    Leaf activities can provide a means of using basic concepts of outdoor education to learn in elementary level subject areas. Equipment needed includes leaves, a clipboard with paper, and a pencil. A bag of leaves may be brought into the classroom if weather conditions or time do not permit going outdoors. Each student should pick a leaf, examine…

  11. Squashed entanglement, k-extendibility, quantum Markov chains, and recovery maps

    E-print Network

    Ke Li; Andreas Winter

    2014-11-06

    Squashed entanglement [Christandl/Winter, JMP 45(3):829-840 (2004)] is a monogamous entanglement measure, which implies that highly extendible states have small value of the squashed entanglement. Here, invoking a recent inequality for the quantum conditional mutual information [Fawzi/Renner, arXiv:1410.0664], we show the converse, that a small value of squashed entanglement implies that the state is close to a highly extendible state. As a corollary, we establish an alternative proof of the faithfulness of squashed entanglement [Brandao/Christandl/Yard, CMP 306:805-830 (2011)]. We briefly discuss the pre-history of the Fawzi-Renner bound and related conjectures, and close by advertising a potentially far-reaching generalization to the monotonicity of the relative entropy.

  12. Analysis of band-gap formation in squashed arm-chair CNT

    E-print Network

    Mehrer, H; Anantram, M P; Elstner, M; Frauenheim, T

    2005-01-01

    The electronic properties of squashed arm-chair carbon nanotubes are modeled using constraint free density functional tight binding molecular dynamics simulations. Independent from CNT diameter, squashing path can be divided into {\\it three} regimes. In the first regime, the nanotube deforms with negligible force. In the second one, there is significantly more resistance to squashing with the force being $\\sim 40-100$ 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 as a function of squashing and our main results are: (i) A band-gap initially opens due to interaction between atoms at the top and bottom sides of CNT. The $\\pi-$orbital approximation is successful in modeling the band-gap opening at this stage. (ii) In the second regime of squashing, large $\\pi-\\sigma$ interaction at the edges becomes important, which can lead to band-gap oscillation. (iii) Contr...

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

    Microsoft Academic Search

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

    2006-01-01

    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

  14. Leaf Development

    PubMed Central

    2013-01-01

    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

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

    PubMed

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

    2006-10-01

    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

  16. A Life History of the Squash Vine Borer, Melittia Cucurbitae (Harris) (Lepidoptera: Sesiidae) in South Carolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The life history of the squash vine borer (Lepidoptera: Sesiidae) was investigated in South Carolina. Duration of life stages, numbers of progeny, and mortality rates for SVB were determined in cages held at 25 plus minus 2C, 65-70% humidity and a photoperiod of 16:8 (L:D) h in a rearing room, and ...

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

    Microsoft Academic Search

    Cynthia S. LeVesque; Thomas M. Perring; Linda L. Walling

    2000-01-01

    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 white- flies were observed. Temporal and spatial studies showed that SLW1 and SLW3 were induced when second, third, and fourth nymphal instars were feeding. Although

  18. Trap Crop Systems for Striped Cucumber Beetle Control in Winter Squash

    Microsoft Academic Search

    Andrew F Cavanagh

    2008-01-01

    CHAPTER 1\\u000aStriped cucumber beetle, Acalymma vittatum F., is the primary insect pest of cucurbit crops in the Northeastern United States. Adult beetles colonize squash crops from field borders, causing feeding damage at the seedling stage and transmitting the bacteria Erwinia tracheiphila Hauben et al. Conventional control methods rely on insecticide applications to the entire field, but surrounding main crops

  19. Radiation and water use efficiencies of greenhouse zucchini squash in relation to different climate parameters

    Microsoft Academic Search

    Youssef Rouphael; Giuseppe Colla

    2005-01-01

    In the Mediterranean region, zucchini squash (Cucurbita pepo L.) is widely grown under unheated greenhouse conditions for off-season production. Climatic conditions affecting both radiation and water use are mainly determined by the planting dates. Elucidating the relationship between the radiation and the water use with climate variables is important for the quantification of crop productivity and for improving water use

  20. 9/15/14 to 9/19/14 Rotisserie Chicken, Saut Yellow Squash, Vegetarian

    E-print Network

    Foroosh, Hassan

    9/15/14 to 9/19/14 Monday Rotisserie Chicken, Sauté Yellow Squash, Vegetarian Moroccan Stew, Sweet Potatoes. Sandwich of the Day: Meat Ball Sub Soup of the day: Chicken Noodle Tuesday Beef Steak Chicken Parmesan, Italian Cheese Balls, Whole Wheat Spaghetti, Italian Seasoned Sauté Spinach. Sandwich

  1. Daily physical activity in ankylosing spondylitis: validity and reliability of the IPAQ and SQUASH and the relation with clinical assessments

    PubMed Central

    2013-01-01

    Introduction The aim of this study was to investigate the construct validity and test-retest reliability of the International Physical Activity Questionnaire (IPAQ; long form) and the Short QUestionnaire to Assess Health-enhancing physical activity (SQUASH) and to investigate the relation between daily physical activity and clinical assessments in patients with ankylosing spondylitis (AS). Methods For validity, the self-report questionnaires IPAQ and SQUASH were compared with daily physical activity assessed with the ActiGraph accelerometer during 7 consecutive days in 63 AS outpatients. For reliability, the IPAQ and SQUASH were administered twice approximately 1 week apart in 52 AS outpatients. In all 115 patients, clinical assessments were performed at the outpatient clinic. Results IPAQ and SQUASH total scores correlated significantly with accelerometer outcome: ? = 0.38 and r = 0.35, respectively. Intraclass correlation coefficients between first and second assessments of the IPAQ and SQUASH were 0.83 and 0.89, respectively. Bland-Altman analyses showed no systemic bias, but in particular for the IPAQ the 95% limits of agreement were wide. Daily physical activity assessed by accelerometer, IPAQ, and SQUASH correlated significantly with disease activity, physical activity, and quality of life. A relation with spinal mobility was found only for the accelerometer and SQUASH. The direction of these correlations indicates that higher daily physical activity is related to lower disease activity and better physical function, spinal mobility and quality of life. Conclusions Both physical activity questionnaires showed modest construct validity. The SQUASH showed good test-retest reliability, superior to the IPAQ. These results indicate that the SQUASH is more suitable than the IPAQ to assess daily physical activity in AS population studies. However, it is desirable to add questions on AS-specific physical activity. Further studies are needed to investigate the causality of the relation between daily physical activity and clinical assessments. PMID:23971767

  2. 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...

  3. 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...

  4. 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...

  5. QUANTIFYING THE IMPACT OF JOINTED CONCRETE PAVEMENT CURLING AND WARPING ON PAVEMENT UNEVENNESS

    Microsoft Academic Search

    George K. Chang; Steven M. Karamihas; Robert Otto Rasmussen; David Merritt; Mark Swanlund

    Curling and warping of jointed concrete pavement (JCP) are well-known phenomena. It is a common belief that this behavior may impact pavement unevenness, and thus driver comfort. This relationship has been difficult to quantify in the past due to lack of adequate field measurements and appropriate analysis techniques. To address this issue, the United States Department of Transportation Federal Highway

  6. Curl antennas over electromagnetic band-gap surface: a low profiled design for CP applications

    Microsoft Academic Search

    Fan Yang; Y. Rahmat-Samii

    2001-01-01

    The curl antenna was proposed as a simple radiator to generate circular polarized electromagnetic waves (see Nakano, H. et al., 1993). The design has been suggested for applications in wireless communications (see Colburn, J.S. and Rahmat-Samii, Y., 1996). However, it cannot work well when it is placed close to a finite PEC ground plane due to its reverse image. Recently,

  7. Wheat curl mite and dry bulb mite: untangling a taxonomic conundrum through a multidisciplinary approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The taxonomy of two economically important eriophyoid species, Aceria tosichella (wheat curl mite, WCM) and A. tulipae (dry bulb mite, DBM), was confounded in the world literature until the late 20th century due to their morphological similarity and ambiguous data from plant-transfer and virus-trans...

  8. Analysis of iterated ADI-FDTD schemes for Maxwell curl equations

    Microsoft Academic Search

    B. D. Welfert

    2007-01-01

    The convergence of the iterative ADI-FDTD method proposed by Wang et al. [S. Wang, F. Teixeira, J. Chen, An iterative ADI-FDTD with reduced splitting error, IEEE Microwave Wireless Comp. Lett. 15 (2005) 1531 1533] towards the classical implicit Crank Nicolson scheme when applied to Maxwell curl equations, and the accuracy, stability, and dispersion properties of the resulting iterated schemes are

  9. Discriminating weak lensing from intrinsic spin correlations using the curl-gradient decomposition

    E-print Network

    Robert G. Crittenden; Priyamvada Natarajan; Ue-Li Pen; Tom Theuns

    2000-12-15

    The distortion field defined by the ellipticities of galaxy shapes projected on the sky can be uniquely decomposed into a gradient and a curl component. If the observed ellipticities are induced by weak gravitational lensing, then the distortion field is curl free. Here we show that, in contrast, the distortion field resulting from intrinsic spin alignments is not curl free. This provides a powerful discriminant between lensing and intrinsic contributions to observed ellipticity correlations. We also show how these contributions can be disentangled statistically from the ellipticity correlations or computed locally from circular integrals of the ellipticity field. This allows for an unambiguous detection of intrinsic galaxy alignments in the data. When the distortions are dominated by lensing, as occurs at high redshifts, the decomposition provides a valuable tool for understanding properties of the noise and systematic errors. These techniques can be applied equally well to the polarization of the microwave background, where it can be used to separate curl-free scalar perturbations from those produced by gravity waves or defects.

  10. 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

    2010-05-25

    ...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...

  11. LEAF MARGIN INFLORESCENCE

    E-print Network

    Holland, Jeffrey

    { LEAF BLADE LEAF MARGIN PETIOLE INFLORESCENCE WS-27-W Guidelines for Submitting Digital Plant RAGWEED VELVETLEAF Leaf arrangement on the plant stem. Alternate Opposite Alternate CANADA THISTLE COMMON RAGWEED VELVETLEAF Leaf attachment to the plant stem. Sessile Petiole Petiole CANADA THISTLE COMMON

  12. Student thinking about the divergence and curl in mathematics and physics contexts

    E-print Network

    Baily, Charles; Pattie, Andrew; van Kampen, Paul; De Cock, Mieke

    2015-01-01

    Undergraduate physics students are known to have difficulties with understanding mathematical tools, and with applying their knowledge of mathematics to physical contexts. Using survey statements based on student interviews and written responses to open-ended questions, we investigated the prevalence of correct and incorrect conceptions regarding the divergence and curl of vector fields, among both mathematics and physics students. We compare and contrast pre-instruction responses from intermediate-level E&M students at KU Leuven and the University of St Andrews with post-instruction responses from St Andrews students enrolled in a vector calculus course. In comparing pre- and post-instruction responses from E&M students we see that, although their understanding of the divergence and curl improved, relatively few of them were able to provide completely correct survey responses at mid-semester.

  13. Confirmation of bean leaf beetle, Cerotoma trifurcata, feeding on cucurbits

    PubMed Central

    Koch, R.L.; Burkness, E.C.; Hutchison, W.D.

    2004-01-01

    The objective of these studies was to assess the degree to which bean leaf beetle, Cerotoma trifurcata (Forster), will feed on cucurbits. In 2003, we documented an infestation of C. trifurcata in a commercial pumpkin field near Rosemount, MN, USA. To evaluate C. trifurcata feeding on cucurbits, we conducted laboratory no-choice and choice test feeding studies. In the laboratory, C. trifurcata fed most heavily on cotyledon-stage cucumber plants, followed by pumpkin and squash. With soybean plants present, C. trifurcata still fed on cucumber plants. However, C. trifurcata appeared to prefer soybeans until the quality of the soybean plants was diminished through feeding damage. This is the first known report of C. trifurcata feeding on cucurbits. The pest potential of C. trifurcata in cucurbit cropping systems should be further evaluated. PMID:15861221

  14. Confirmation of bean leaf beetle, Cerotoma trifurcata, feeding on cucurbits.

    PubMed

    Koch, R L; Burkness, E C; Hutchison, W D

    2004-01-01

    The objective of these studies was to assess the degree to which bean leaf beetle, Cerotoma trifurcata (Forster), will feed on cucurbits. In 2003, we documented an infestation of C. trifurcata in a commercial pumpkin field near Rosemount, MN, USA. To evaluate C. trifurcata feeding on cucurbits, we conducted laboratory no-choice and choice test feeding studies. In the laboratory, C. trifurcata fed most heavily on cotyledon-stage cucumber plants, followed by pumpkin and squash. With soybean plants present, C. trifurcata still fed on cucumber plants. However, C. trifurcata appeared to prefer soybeans until the quality of the soybean plants was diminished through feeding damage. This is the first known report of C. trifurcata feeding on cucurbits. The pest potential of C. trifurcata in cucurbit cropping systems should be further evaluated. PMID:15861221

  15. The nuts and bolts of supersymmetric gauge theories on biaxially squashed three-spheres

    E-print Network

    Martelli, Dario

    2011-01-01

    We present the gravity dual to a class of three-dimensional N=2 supersymmetric gauge theories on a biaxially squashed three-sphere, with a non-trivial background gauge field. This is described by a 1/2 BPS Euclidean solution of four-dimensional N=2 gauged supergravity, consisting of a Taub-NUT-AdS metric with a non-trivial instanton for the graviphoton field. The holographic free energy of this solution agrees precisely with the large N limit of the free energy obtained from the localized partition function of a class of Chern-Simons quiver gauge theories. We also discuss a different supersymmetric solution, whose boundary is a biaxially squashed Lens space S^3/Z_2 with a topologically non-trivial background gauge field. This metric is of Eguchi-Hanson-AdS type, although it is not Einstein, and has a single unit of gauge field flux through the S^2 cycle.

  16. Analysis of iterated ADI-FDTD schemes for Maxwell curl equations

    Microsoft Academic Search

    B. D. Welfert

    2007-01-01

    The convergence of the iterative ADI-FDTD method proposed by Wang et al. [S. Wang, F. Teixeira, J. Chen, An iterative ADI-FDTD with reduced splitting error, IEEE Microwave Wireless Comp. Lett. 15 (2005) 1531–1533] towards the classical implicit Crank–Nicolson scheme when applied to Maxwell curl equations, and the accuracy, stability, and dispersion properties of the resulting iterated schemes are investigated. The

  17. A virus and its vector, pepper yellow leaf curl virus and Bemisia tabaci , two new invaders of Indonesia

    Microsoft Academic Search

    Paul J. De Barro; Sri Hendrastuti Hidayat; Don Frohlich; Siti Subandiyah; Shigenori Ueda

    2008-01-01

    Bemisia tabaci is a species of sap-sucking insect belonging to the Aleyrodidae and are commonly known as whiteflies. The species is made\\u000a up of a complex of distinct genetic groups which have a strong geographic pattern to their genetic structure. Two members\\u000a of this complex known as the B and Q biotypes have proven to be particularly invasive, spreading with

  18. Engineering cotton ( Gossypium hirsutum L.) for resistance to cotton leaf curl disease using viral truncated AC1 DNA sequences

    Microsoft Academic Search

    Jamil A. HashmiYusuf; Yusuf Zafar; Muhammad Arshad; Shahid Mansoor; Shaheen Asad

    2011-01-01

    Several important biological processes are performed by distinct functional domains found on replication-associated protein\\u000a (Rep) encoded by AC1 of geminiviruses. Two truncated forms of replicase (tAC1) gene, capable of expressing only the N-terminal\\u000a 669 bp (5?AC1) and C-terminal 783 bp (3?AC1) nucleotides cloned under transcriptional control of the CaMV35S were introduced\\u000a into cotton (Gossypium hirsutum L.) using LBA4404 strain of Agrobacterium tumefaciens

  19. Effect of Crotalaria juncea Amendment on Squash Infected with Meloidogyne incognita1

    Microsoft Academic Search

    K.-H. Wang; R. McSorley; R. N. Gallaher

    2004-01-01

    Two greenhouse experiments were conducted to examine the effect of Crotalaria juncea amendment on Meloidogyne incognita population levels and growth of yellow squash (Cucurbita pepo). In the first experiment, four soils with a long history of receiving yard waste compost (YWC+), no-yard-waste compost (YWC), conventional tillage, or no-tillage treatments were used; in the second experiment, only one recently cultivated soil

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

    PubMed

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

    2014-10-01

    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

  1. On Instability of Squashed Spheres in the Kaluza-Klein Theory

    E-print Network

    Kiyoshi Shiraishi

    2014-06-20

    We study in Kaluza-Klein theories stability of the extra space against "squashing", in other words, the homogeneous deformation. Quantum fluctuations of matter fields at one-loop level are taken into consideration. We calculate the effective potential in models of the type, $M^4\\times S^3$ and $M^4\\times S^7$. It is found that in the case of scalar matter fields the stability depends on the coupling to the scalar curvature.

  2. Slow expiration reduces sternocleidomastoid activity and increases transversus abdominis and internal oblique muscle activity during abdominal curl-up.

    PubMed

    Yoon, Tae-Lim; Kim, Ki-Song; Cynn, Heon-Seock

    2014-04-01

    The aim of this study was to investigate the effects of quiet inspiration versus slow expiration on sternocleidomastoid (SCM) and abdominal muscle activity during abdominal curl-up in healthy subjects. Twelve healthy subjects participated in this study. Surface electromyography (EMG) was used to collect activity of bilateral SCM, rectus abdominis (RA), external oblique (EO), and transversus abdominis/internal oblique (TrA/IO) muscles. A paired t-test was used to determine significant differences in the bilateral SCM, RF, EO, and TrA/IO muscles between abdominal curl-up with quiet inspiration and slow expiration. There were significantly lower EMG activity of both SCMs and greater EMG activity of both IOs during abdominal curl-up with slow expiration, compared with the EMG activity of both SCMs and IOs during abdominal curl-up with quiet inspiration (p<.05). The results of this study suggest that slow expiration would be recommended during abdominal curl-up for reduced SCM activation and selective activation of TrA/IO in healthy subjects compared with those in abdominal curl up with quiet inspiration. PMID:24210796

  3. Self-curled coral-like ?-Al2O3 nanoplates for use as an adsorbent.

    PubMed

    Wang, Xianbiao; Zhan, Chuanliang; Kong, Biao; Zhu, Xiaoguang; Liu, Jin; Xu, Wenzong; Cai, Weiping; Wang, Huanting

    2015-09-01

    Biomimetic self-curled nanoplates assembled coral-like nanoporous ?-Al2O3 has been prepared by a solvothermal method using ethylene glycol (EG)H2O as the mixed solvent, followed by the annealing process. The resulting samples are composed of micro/nanostructured units (?1.5?m) with self-curled porous nanoplates on the surface. The volume ratio of EG to water in precursor solution is crucial for the formation of coral-like structure. The formation process is investigated to be an assembly process with self-curled nanoplates driven by adsorption of EG. Importantly, the coral-like porous ?-Al2O3 has high surface area of 64.18m(2)/g and exhibits enhanced adsorption performance for efficient removal of heavy metal Hg(II) (49.15mg/g). The removal capacity is higher than (?2.5times) those of commercial Al2O3 nanoparticles and hollow structured ?-Al2O3 prepared without EG (?2.7times). Further investigation shows adsorption behaviors of the coral-like ?-Al2O3 and the alumina hollow structure can be well described by Langmuir isotherm model, whereas that of commercial Al2O3 nanoparticles fits Freundlich isotherm model. This work not only provides an inspiration for high efficient biomimetic adsorbent but also presents a facile route for coral-like ?-Al2O3 preparation. PMID:25989055

  4. ANALYSIS OF TRITIUM INCORPORATION INTO INDIVIDUAL CELLS BY AUTORADIOGRAPHY OF SQUASH PREPARATIONS

    PubMed Central

    Wimber, Donald E.; Quastler, Henry; Stein, Otto L.; Wimber, Doris R.

    1960-01-01

    The relation between tritium content of individual cells and grain count obtained in autoradiographs of squashed cells was investigated. The tissues used were root meristems of Tradescantia paludosa and intestinal epithelium of the mouse. The relation between grain count and tritium content is affected by self-absorption which depends on the thickness of the labeled cell. Therefore, squashed preparations were sectioned to determine the uniformity of thickness of nuclei. In a preparation of mouse cells, thicknesses were 1.18 ± 0.35 µ, and in a preparation of Tradescantia cells, 2.97 ± 0.35 µ. The effects of similar and larger variations in thickness upon grain count were studied in material squashed with different pressures; no marked correlation was found. The lack of correlation is explained by the geometric relation between labeled nuclei and the emulsion. By counting grains and directly measuring tritium content in a glass proportional counting tube in the same preparation, the yield of grains per disintegration was measured in Tradescantia cells and found to be 1 grain for 10.9 disintegrations with AR 10 autoradiographic film and 1 grain for 19.3 disintegrations for NTB nuclear track liquid emulsion. Latent image fading may pose a problem with long exposures; the conditions of its occurrence are as yet not well known. PMID:13785740

  5. Leaf Modeling and Constrained Leaf Morphing in Leaf Space Saurabh Garg1

    E-print Network

    Leow, Wee Kheng

    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

  6. Regulation of Compound Leaf Development by PHANTASTICA in Medicago truncatula1[C][W][OPEN

    PubMed Central

    Ge, Liangfa; Peng, Jianling; Berbel, Ana; Madueño, Francisco; Chen, Rujin

    2014-01-01

    Plant leaves, simple or compound, initiate as peg-like structures from the peripheral zone of the shoot apical meristem, which requires class I KNOTTED-LIKE HOMEOBOXI (KNOXI) transcription factors to maintain its activity. The MYB domain protein encoded by the ASYMMETRIC LEAVES1/ROUGH SHEATH2/PHANTASTICA (ARP) gene, together with other factors, excludes KNOXI gene expression from incipient leaf primordia to initiate leaves and specify leaf adaxial identity. However, the regulatory relationship between ARP and KNOXI is more complex in compound-leafed species. Here, we investigated the role of ARP and KNOXI genes in compound leaf development in Medicago truncatula. We show that the M. truncatula phantastica mutant exhibited severe compound leaf defects, including curling and deep serration of leaf margins, shortened petioles, increased rachises, petioles acquiring motor organ characteristics, and ectopic development of petiolules. On the other hand, the M. truncatula brevipedicellus mutant did not exhibit visible compound leaf defects. Our analyses show that the altered petiole development requires ectopic expression of ELONGATED PETIOLULE1, which encodes a lateral organ boundary domain protein, and that the distal margin serration requires the auxin efflux protein M. truncatula PIN-FORMED10 in the M. truncatula phantastica mutant. PMID:24218492

  7. Elm Leaf Beetle

    E-print Network

    Patrick, Carl D.

    2002-05-22

    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...

  8. 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...

  9. Squash trypsin inhibitors from Momordica cochinchinensis exhibit an atypical macrocyclic structure.

    PubMed

    Hernandez, J F; Gagnon, J; Chiche, L; Nguyen, T M; Andrieu, J P; Heitz, A; Trinh Hong, T; Pham, T T; Le Nguyen, D

    2000-05-16

    Three trypsin inhibitors (TIs), from the seeds of the squash Momordica cochinchinensis (MCo), have been isolated and purified using gel filtration, ion exchange chromatography, and reverse-phase HPLC. Their sequences could be determined only after proteolytic cleavages. In the case of MCoTI-I and -II, it was shown that their polypeptide backbones are cyclic, a structure that has never been described in squash TIs. They contain 34 amino acid residues with 3 disulfide bridges and measured molecular masses of 3453.0 and 3480.7, respectively. They are the largest known macrocyclic peptides containing disulfide bridges. Their sequences show strong homology to other squash TIs, suggesting a similar three-dimensional structure and an analogous mechanism of action. A model of MCoTI-II was constructed by analogy to the crystal structure of the complex between bovine trypsin and CMTI-I, indicating that the linker connecting the two termini is flexible and does not impose significant geometrical constraints. This flexibility allows an Asp-Gly peptide bond rearrangement to occur in this region, giving rise to two isoforms of MCoTI-II. Although the importance of cyclization is not clear, it might confer increased stability and resistance to proteolysis. A minor species, MCoTI-III, was also characterized as containing 30 amino acid residues with a molecular mass of 3379.6. This component possesses a linear backbone with a blocked N-terminus. MCoTIs represent interesting candidates for drug design, either by changing their specificity of inhibition or by using their structure as natural scaffolds bearing new binding activities. PMID:10801322

  10. Electronic structure of trypsin inhibitor from squash seeds in aqueous solution

    NASA Astrophysics Data System (ADS)

    Zheng, Haoping

    2000-10-01

    The electronic structure of the trypsin inhibitor from seeds of the squash Cucurbita maxima (CMTI-I) in aqueous solution is obtained by ab initio, all-electron, full-potential calculations using the self-consistent cluster-embedding (SCCE) method. The reactive site of the inhibitor is explained theoretically, which is in agreement with the experimental results. It is shown that the coordinates of oxygen atoms in the inhibitor, determined by nuclear magnetic resonance and combination of distance geometry and dynamical simulated annealing, are systematically less accurate than that of other kinds of heavy atoms.

  11. Electronic structure of trypsin inhibitor from squash seeds in aqueous solution.

    PubMed

    Zheng, H

    2000-10-01

    The electronic structure of the trypsin inhibitor from seeds of the squash Cucurbita maxima (CMTI-I) in aqueous solution is obtained by ab initio, all-electron, full-potential calculations using the self-consistent cluster-embedding (SCCE) method. The reactive site of the inhibitor is explained theoretically, which is in agreement with the experimental results. It is shown that the coordinates of oxygen atoms in the inhibitor, determined by nuclear magnetic resonance and combination of distance geometry and dynamical simulated annealing, are systematically less accurate than that of other kinds of heavy atoms. PMID:11089109

  12. Photoreceptor for curling behavior in Peranema trichophorum and evolution of eukaryotic rhodopsins.

    PubMed

    Saranak, Jureepan; Foster, Kenneth W

    2005-10-01

    When it is gliding, the unicellular euglenoid Peranema trichophorum uses activation of the photoreceptor rhodopsin to control the probability of its curling behavior. From the curled state, the cell takes off in a new direction. In a similar manner, archaea such as Halobacterium use light activation of bacterio- and sensory rhodopsins to control the probability of reversal of the rotation direction of flagella. Each reversal causes the cell to change its direction. In neither case does the cell track light, as known for the rhodopsin-dependent eukaryotic phototaxis of fungi, green algae, cryptomonads, dinoflagellates, and animal larvae. Rhodopsin was identified in Peranema by its native action spectrum (peak at 2.43 eV or 510 nm) and by the shifted spectrum (peak at 3.73 eV or 332 nm) upon replacement of the native chromophore with the retinal analog n-hexenal. The in vivo physiological activity of n-hexenal incorporated to become a chromophore also demonstrates that charge redistribution of a short asymmetric chromophore is sufficient for receptor activation and that the following isomerization step is probably not required when the rest of the native chromophore is missing. This property seems universal among the Euglenozoa, Plant, and Fungus kingdom rhodopsins. The rhodopsins of animals have yet to be studied in this respect. The photoresponse appears to be mediated by Ca2+ influx. PMID:16215167

  13. 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.

  14. Squash Cytology in Neurosurgical Practice: A Useful Method in Resource-Limited Setting with Lack of Frozen Section Facility

    PubMed Central

    Agrawal, Manish; Chandrakar, Shiv kumar; Lokwani, Dharampal

    2014-01-01

    Background: Intra-operative cytology is an important diagnostic tool. It has shown to play an important role especially in the diagnosis of central nervous system tumours. The study was done to assess the feasibility of squash cytology as standalone diagnostic test in setting where frozen section facility is not available. Materials and Methods: Total 48 patients with various intracranial lesions were initially enrolled in the study. Patients were investigated by various radio-imaging techniques and routine blood investigations. Forty-one patients were operated at Netaji Subhash Chandra Bose medical college, Jabalpur. Intra-operative squash cytology diagnosis was performed and was correlated with histology diagnosis as gold standard. Results: Out of 41 patients, inflammatory lesions were diagnosed in nine patients while benign lesions [most common neurilemmoma and meningioma] were observed in 21 and malignant lesions [astrocytoma was most common] were diagnosed in 11 patients. Diagnostic accuracy of intra-operative squash cytology irrespective of lesion & site was 95%. We were able to inform about the diagnosis to neurosurgeon in 15 minutes in all cases and within 12 minutes in >85% cases Conclusion: Squash smear cytology is reliable and rapid standalone diagnostic method and it can assist for intra-operative decision-making diagnosis of intracranial lesions in resource-limited settings where frozen section facility is not available. PMID:25478346

  15. Serratia marcescens, a phloem-colonizing, squash bug-transmitted bacterium: Causal agent of cucurbit yellow vine disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucurbit yellow vine disease (CYVD), which can inflict heavy losses to watermelon, pumpkin, cantaloupe and squash in U. S. production areas from the mid-west to northeast, causes phloem discoloration, foliar yellowing, wilting, and plant decline. By electron microscopy, the disease had been previou...

  16. Squashing the Millennium Bug: A Year 2000 Compliance Guide for Elementary/Secondary Schools and School Districts.

    ERIC Educational Resources Information Center

    Root, Mark; Carlson, Robert; Dexter, David; Karinch, Samantha; Kaplan, Heather

    This guide was developed to assist the nation's elementary and secondary schools and school districts address their Year 2000 (Y2K) problem. The guide is divided into three sections: Squashing the Millennium Bug Step-by-Step; Remediating Specific Types of Systems; and Appendix. The first chapter presents the following steps for tackling the Year…

  17. 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, ...

  18. Effects and carry-over benefits of nematicides in soil planted to a sweet corn-squash-vetch cropping system.

    PubMed

    Johnson, A W; Leonard, R A

    1995-12-01

    The effects of irrigation on the efficacy of nematicides on Meloidogyne incognita race 1 population densities, yield of sweet corn, and the carry-over of nematicidal effect in the squash crop were determined in a sweet corn-squash-vetch cropping system for 3 years. Fenamiphos 15G and aldicarb 15G were applied at 6.7 kg a.i./ha and incorporated 15 cm deep with a tractor-mounted rototiller. Ethylene dibromide (EDB) was injected at 18 kg a.i./ha on each side of the sweet corn rows (total 36 kg a.i./ha) at planting for nematode control. Supplemental sprinkler irrigation (1.52-4.45 cm), applied in addition to natural rainfall (4.60-10.80 cm) within l0 days after application of nematicides, did not affect nematicide efficacy against M. incognita or yield of sweet corn. Soil treatment with fenamiphos, EDB, and aldicarb increased the number and total weight of sweet corn ears and the weight per ear each year over untreated controls (P squash planted after sweet corn, but yields were consistently greater and root-gall indices lower on squash following sweet corn treated with fenamiphos than other nematicides. PMID:19277323

  19. The effect of MSW compost and fertilizer on extractable soil elements and the growth of winter squash in Nova Scotia

    Microsoft Academic Search

    P. R. Warman; A. V. Rodd; P. Hicklenton

    2009-01-01

    Municipal solid waste (MSW) compost is an ‘organic’ amendment and can influence nutrient mineralization and subsequent plant growth. A three-year field experiment evaluated the effects of MSW compost and fertilizer on soil fertility and elemental analysis of squash (Cucurbita maxima cv. Buttercup) grown in a Pugwash sandy loam soil in Nova Scotia, Canada. Three rates of compost (MSW1, MSW2, and

  20. Progress and Challenges in Managing Watermelon Vine Decline caused by whitefly transmitted Squash Vein Yellowing Virus (SqVYV)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watermelon vine decline (WVD) is an emerging threat to watermelon production in south-west and west-central Florida. Losses in 2004-2005 due to WVD were estimated to be more than 60 million U.S. dollars. The disease is caused by Squash vein yellowing virus (SqVYV), family: Potyviridae, genus: Ip...

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

    Microsoft Academic Search

    A. B. Sandø; T. Furevik

    2008-01-01

    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

  2. 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...

  3. [Molecular mechanism of leaf development].

    PubMed

    Yan, Song; Yan, Chang-Jie; Gu, Ming-Hong

    2008-09-01

    Leaf plays important roles during plant development for their function of photosynthesis and transpiration. Leaf development includes initiation of leaf primordium and establishment of leaf polarity. Various studies indicate that leaf development is controlled through the interaction of transcription factors, small RNAs and auxin. This review focuses on re-cent advances in studying on leaf development and morphogenesis, and provides information on the regulation network in the process. PMID:18779169

  4. ASCOCHYTA LEAF SPOT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascochyta leaf spot is a plant disease of wheat. It is often overlooked in association with other leaf spot diseases on wheat and is generally of minor economic importance in Europe, Japan, New Zealand, and North America. However, its distribution and frequency may be greater than realized, becaus...

  5. Leaf cutter ants

    NSDL National Science Digital Library

    N/A N/A (None; )

    2007-12-15

    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.

  6. 1H-n.m.r. studies of squash seed trypsin inhibitor.

    PubMed

    Likos, J J

    1989-11-01

    1H-n.m.r. studies at 500 MHz have been performed on a trypsin inhibitor (CMTI-III) found in squash seed (Cucurbita maxima). The sequential resonance assignments have been made using two-dimensional techniques. The chemical shifts for the assigned protons are reported at 30 degrees, pH 2.8 and form a basis for the determination of the solution structure of CMTI-III. Analysis of the NOE data, NH-alpha CH vicinal coupling constants and pattern of slowly exchanging amide protons indicates that the predominant feature of the solution conformation is a triple stranded beta sheet consisting of residues 8-10, 21-23, and 26-29. Residues 12-15 appear to form a beta turn. PMID:2613440

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

    E-print Network

    Minnesota, University of

    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

  8. Short communication Leaf optical properties and photosynthetic leaf absorptances

    E-print Network

    Durako, Michael J.

    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

  9. Comparison of wind-stress algorithms and their influence on wind-stress curl using buoy measurements over the shelf off Bodega Bay, California

    NASA Astrophysics Data System (ADS)

    Kochanski, Adam; Kora?in, Darko; Dorman, Clive E.

    2006-12-01

    The main objectives of this study were to compare three wind-stress algorithms of varying intricacy and estimate the extent to which each method altered computed wind-stress curl. The algorithms included (1) a simple bulk formula for neutral conditions that is dependent only on wind velocity components; (2) a formula that in addition to dependence on wind components includes a simplified effect of thermal stability through differences in air and sea temperatures; and (3) an algorithm that includes full treatment of dynamics and atmospheric stability. Data for the analysis were from a field program that used a special buoy network off Bodega Bay during 28 June-4 August 2001. A diamond-shaped setup of five closely separated buoys in Bodega Bay allowed for one of the first attempts to compute wind-stress curl over the ocean using buoy measurements. Based on an analysis of the available dataset, the marine layer over Bodega Bay is characterized by positive wind-stress curl with a median value around 0.2 Pa (100 km) -1 and maximum values reaching 2.5 Pa (100 km) -1. Positive wind-stress curl was observed for all wind speed conditions, whereas negative wind-stress curl episodes were associated mostly with low-wind conditions. Comparison of wind-stress curl computed using the three algorithms showed that differences among them can be significant. The first and third algorithms indicated similar stress curl (difference around 10%), but the differences between these two and the second algorithm were much higher (approximately 40%). The reason for the difference is the stability correction, which in the third algorithm strongly decreases with an increase in wind speeds, but stays at a similar level for all wind speeds in the second algorithm. Consequently, for higher wind speeds the variability of wind stress calculated using the second algorithm is greater than for the other two algorithms, causing significant differences in computed wind-stress curl (root mean-square error equal to 0.19 Pa (100 km) -1). Despite the apparent biases in computed wind stress and wind-stress curl among the algorithms, all of them show a significant trend of decreasing sea-surface temperature (SST) with increasing wind-stress curl. The bootstrapping analysis has revealed that both the along-shore wind stress and wind-stress curl have noticeable correlation with the changes in the sea-surface temperature as an indirect indication of the upwelling. An additional analysis, based on the low-pass filtered data, showed also significant agreement between the measured divergence in the cross-shore surface transport and the wind-stress curl computed for all three algorithms.

  10. Elm Leaf Beetle 

    E-print Network

    Patrick, Carl D.

    2002-05-22

    stream_source_info pdf_1591.pdf.txt stream_content_type text/plain stream_size 5918 Content-Encoding UTF-8 stream_name pdf_1591.pdf.txt Content-Type text/plain; charset=UTF-8 Elm Leaf Beetles L-1812 5-02 Carl D. Patrick... overwintering sites. *Extension Entomologist, The Texas A&M University System. Elm leaf beetle adult. Damage Elm leaf beetles feed exclusively on foliage. Adult feeding causes small, circular holes in leaves. Larval feeding removes most of the green material...

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

    PubMed Central

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

    1997-01-01

    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

  12. Effect of ambient storage on the quality characteristics of aerobically packaged fish curls incorporated with different flours.

    PubMed

    Raja, Waseem Hussain; Kumar, Sunil; Bhat, Zuhaib Fayaz; Kumar, Pavan

    2014-01-01

    The present study was conducted to evaluate the effect of ambient storage on the quality attributes of aerobically packaged fish curls incorporated with optimum levels of different flours. The curls were developed by extrusion technology using fish meat (Catla catla). The fish curls containing optimum levels of different flours viz. 20 percent corn flour, 10 percent black gram flour and 10 percent peanut flour were compared with the control snacks containing 30 percent rice flour and assessed for storage quality and shelf life at ambient temperature. The curls were aerobically packaged in LDPE (low density polyethylene) pouches and evaluated for various physicochemical, microbiological and sensory parameters. Mean values of pH of all the curls showed significantly (p?curls incorporated with optimum level of different flours were acceptable up to 21 days of ambient storage within the LDPE pouches. PMID:24624316

  13. Electronic Leaf Project

    NSDL National Science Digital Library

    Carolyn Houston

    2000-05-01

    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

  14. Leaf Tissue Senescence

    PubMed Central

    Manos, Peter J.; Goldthwaite, Jonathan

    1975-01-01

    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

  15. Leaf to Landscape

    Microsoft Academic Search

    Alessandro Cescatti; Ülo Niinemets

    \\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

  16. A high speed profiler based slab curvature index for jointed concrete pavement curling and warping analysis

    NASA Astrophysics Data System (ADS)

    Byrum, Christopher Ronald

    One of the biggest gaps of missing knowledge between accurate structural modeling of concrete pavement slab behavior and real pavement behavior is accounting for slab warping (locked-in curvature and moisture gradient effects) and curling (temperature gradient effects). Curling and warping are curvatures that can be present in a PCC slab that can cause corners and edges, or mid panel, of the slab to lift off of the ground resulting in relatively high deflection and stress in the system. The least understood type of curvature in slabs is apparent locked-in curvature, which can become excessive and control the overall behavior of the pavement system. This project is focused on quantifying slab curvatures and the effects of apparent locked-in curvature on the behavior and long-term performance of pavement systems. A high-speed profile analysis technique for detecting the amount of slab curvatures along pavement wheel paths is described. This signal processing technique can detect relatively small curvature variations in high-speed pavement elevation profiles obtained at normal highway operating speeds using special vehicles. A resulting curvature detection algorithm is applied to the Federal Highway Administration (FHWA) Long Term Pavement Performance (LTPP) database high-speed pavement profiles for jointed concrete pavements. The range and nature of slab curvatures detected in the profiles is described. The calculated locked-in curvature at the various pavement sites is compared to LTPP database information to evaluate curvature effects on pavement deterioration rates and the relation between site parameters and locked-in curvature. The significance of slab curvature is shown through statistics and predictive models developed for various pavement distress modes. It is shown that the amount of curvature locked into concrete slabs is one of the strongest factors in the FHWA LTPP data correlated to deterioration of pavements. This study shows that preventing locked-in slab curvature should be a top priority for PCC slabs in highway applications. The profile analysis routine and distress prediction models developed will be valuable tools for pavement designers, managers, and researchers.

  17. Effects of a Resistant Corn Hybrid and Fenamiphos on Meloidogyne incognita in a Corn-Squash Rotation.

    PubMed

    Johnson, A W; Sumner, D R; Windham, G L; Williams, W P

    1999-06-01

    The efficacy of a double-cross corn (Zea mays) hybrid (Old Raccoon selection X T216) X (Tebeau selection X Mp 307) resistant to Meloidogyne incognita as a rotational crop, and fenamiphos treatment for management of root-knot nematode (M. incognita race 1) in squash (Cucurbita pepo var. melopepo) was evaluated in field tests during 1996 and 1997. Numbers of M. incognita in the soil and root-gall indices were lower on the resistant hybrid than on a commercial cultivar DeKalb DK-683. Treatment means across both corn entries had lower root-gall indices following fenamiphos treatment. In soil collected 2 September 1997, there were more colony-forming units (cfu) per gram of oven-dried soil of Pythium spp. from plots planted to DK-683 treated with fenamiphos than in untreated plots (88 vs. 59 cfu). Some corn plots had individual plants with 10% to 15% of the crown and brace roots decayed, but no differences due to fenamiphos treatment. Lodging of stalks was 40% to 50% more in the double-cross hybrid than in DK-683. Yield was greater from DK-683 than the double-cross hybrid. Based on cultivar means across fenamiphos treatments and fenamiphos treatment means across cultivars, root-gall indices and yield of squash were significantly lower following the double cross hybrid than DK-683 and in fenamiphos-treated plots than in untreated plots of squash. Yield of squash was not affected by at-planting treatment with fenamiphos on the preceding crops of corn. Nematode resistance must be transferred into the elite materials of commercial seed companies to reach its full potential as a nematode management strategy. PMID:19270888

  18. Effects of a Resistant Corn Hybrid and Fenamiphos on Meloidogyne incognita in a Corn-Squash Rotation

    PubMed Central

    Johnson, A. W.; Sumner, D. R.; Windham, G. L.; Williams, W. P.

    1999-01-01

    The efficacy of a double-cross corn (Zea mays) hybrid (Old Raccoon selection X T216) X (Tebeau selection X Mp 307) resistant to Meloidogyne incognita as a rotational crop, and fenamiphos treatment for management of root-knot nematode (M. incognita race 1) in squash (Cucurbita pepo var. melopepo) was evaluated in field tests during 1996 and 1997. Numbers of M. incognita in the soil and root-gall indices were lower on the resistant hybrid than on a commercial cultivar DeKalb DK-683. Treatment means across both corn entries had lower root-gall indices following fenamiphos treatment. In soil collected 2 September 1997, there were more colony-forming units (cfu) per gram of oven-dried soil of Pythium spp. from plots planted to DK-683 treated with fenamiphos than in untreated plots (88 vs. 59 cfu). Some corn plots had individual plants with 10% to 15% of the crown and brace roots decayed, but no differences due to fenamiphos treatment. Lodging of stalks was 40% to 50% more in the double-cross hybrid than in DK-683. Yield was greater from DK-683 than the double-cross hybrid. Based on cultivar means across fenamiphos treatments and fenamiphos treatment means across cultivars, root-gall indices and yield of squash were significantly lower following the double cross hybrid than DK-683 and in fenamiphos-treated plots than in untreated plots of squash. Yield of squash was not affected by at-planting treatment with fenamiphos on the preceding crops of corn. Nematode resistance must be transferred into the elite materials of commercial seed companies to reach its full potential as a nematode management strategy. PMID:19270888

  19. Utilization of applied fertilizer nitrogen and irrigation water by drip-fertigated squash as determined by nuclear and traditional techniques

    Microsoft Academic Search

    Munir Jamil Mohammad

    2004-01-01

    Field experiments were conducted to evaluate utilization of applied nitrogen (N) and irrigation water to squash in response to method of fertilizer application and rates of fertigation N. The following treatments were studied in a randomized complete block design with four replications: zero N (N0), 50 (N1), 100 (N2) and 150 (N3) mg N L-1 in the irrigation water (IW).

  20. Damped leaf flexure hinge

    NASA Astrophysics Data System (ADS)

    Chen, Zhong; Chen, Guisheng; Zhang, Xianmin

    2015-05-01

    Flexure-based mechanism like compliant actuation system embeds complex dynamics that will reduce the control bandwidth and limits their dynamic positioning precision. This paper presents a theoretical model of a leaf flexure hinge with damping layers using strain energy method and Kelvin damping model. The modified loss factor of the damped leaf flexure hinge is derived, and the equivalent viscous damping coefficient of the damped leaf hinge is obtained, which could be used to improve the pseudo-rigid-model. The free vibration signals of the hinge in three different damping configurations are measured. The experimental modal analysis also is performed on the three kinds of damped leaf flexure hinges in order to evaluate their 1st order bending natural frequency and vibration-suppressing effects. The evaluation of modified loss factor model also is performed. The experimental results indicate that the constrained layer damping can enhance the structure damping of the hinge even if only single damping layer each side, the modified loss factor model can get good predicts of a damped leaf flexure hinge in the frequency range below 1st order natural frequency, and it is necessary that the dimensional parameters of the damping layers and basic layer of the hinge should be optimized for simplification at the mechanism's design stage.

  1. Damped leaf flexure hinge.

    PubMed

    Chen, Zhong; Chen, Guisheng; Zhang, Xianmin

    2015-05-01

    Flexure-based mechanism like compliant actuation system embeds complex dynamics that will reduce the control bandwidth and limits their dynamic positioning precision. This paper presents a theoretical model of a leaf flexure hinge with damping layers using strain energy method and Kelvin damping model. The modified loss factor of the damped leaf flexure hinge is derived, and the equivalent viscous damping coefficient of the damped leaf hinge is obtained, which could be used to improve the pseudo-rigid-model. The free vibration signals of the hinge in three different damping configurations are measured. The experimental modal analysis also is performed on the three kinds of damped leaf flexure hinges in order to evaluate their 1st order bending natural frequency and vibration-suppressing effects. The evaluation of modified loss factor model also is performed. The experimental results indicate that the constrained layer damping can enhance the structure damping of the hinge even if only single damping layer each side, the modified loss factor model can get good predicts of a damped leaf flexure hinge in the frequency range below 1st order natural frequency, and it is necessary that the dimensional parameters of the damping layers and basic layer of the hinge should be optimized for simplification at the mechanism's design stage. PMID:26026549

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

    E-print Network

    Weitz, Joshua S.

    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 4 Overview of the LEAF GUI layout

  3. Relaxation matrix refinement of the solution structure of squash trypsin inhibitor.

    PubMed

    Nilges, M; Habazettl, J; Brünger, A T; Holak, T A

    1991-06-01

    The structure of the small squash trypsin inhibitor CMTI-I is refined by directly minimizing the difference between the observed two-dimensional nuclear Overhauser enhancement (NOE) intensities and those calculated by the full relaxation matrix approach. To achieve this, a term proportional to this difference was added to the potential energy function of the molecular dynamics program X-PLOR. Derivatives with respect to atomic co-ordinates are calculated analytically. Spin diffusion effects are thus accounted for fully during the refinement. Initial structures for the refinement were those determined recently by solution nuclear magnetic resonance using the isolated two-spin approximation to derive distance range estimates. The fits to the nuclear magnetic resonance data improve significantly with only small shifts in the refined structures during a few cycles of conjugate gradient minimization. However, larger changes (approximately 1 A) in the conformation occur during simulated annealing, which is accompanied by a further reduction of the difference between experimental and calculated two-dimensional NOE intensities. The refined structures are closer to the X-ray structure of the inhibitor complexed with trypsin than the initial structures. The root-mean-square difference for backbone atoms between the initial structures and the X-ray structure is 0.96 A, and that between the refined structures and the X-ray structure 0.61 A. PMID:2051485

  4. Inhibition of human beta-factor XIIa by squash family serine proteinase inhibitors.

    PubMed

    Wynn, R; Laskowski, M

    1990-02-14

    Many inhibitors of trypsin and human beta-factor XIIa have been isolated from squash and related seeds and sequenced (Wieczorek et al., Biochem. Biophys. Res. Comm. (1985) 126, 646-652). The association equilibrium constants (Ka) of several of these inhibitors have now been determined with human beta-factor XIIa using a modification of the method of Green and Work (Park et al., Fed. Proc. Fed. Am. Soc. Exp. Biol. (1984) 43, 1962). The Ka's range from 7.8 x 10(4) M-1 to 3.3 x 10(8) M-1. Two isoinhibitors from Cucurbita maxima seeds, CMTI-I and CMTI-III, differ in only a single glutamate to lysine change in the P'4 position. This results in a factor of 62 increase in the Ka of the lysine inhibitor, CMTI-III (Ka = 3.3 x 10(8) M-1). To our knowledge, this is the largest effect ever seen for a residue substitution at the P'4 position of a serine proteinase inhibitor. The result is even more surprising because beta-factor XIIa's natural substrate, Factor XI, contains Gly in the P'4 position. PMID:2306254

  5. Leaf Hydraulics Lawren Sack1

    E-print Network

    Sack, Lawren

    Leaf Hydraulics Lawren Sack1 and N. Michele Holbrook2 1 Department of Botany, University of Hawai the leaf constitute a substantial (30%) part of the resistance to water flow through plants, and thus influence rates of transpiration and photosynthesis. Leaf hydraulic conductance (Kleaf) varies more than 65

  6. 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...

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

    PubMed

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

    1998-01-01

    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

  8. Humidity-responsive liquid crystalline polymer actuators with an asymmetry in the molecular trigger that bend, fold, and curl.

    PubMed

    de Haan, Laurens T; Verjans, Julien M N; Broer, Dirk J; Bastiaansen, Cees W M; Schenning, Albertus P H J

    2014-07-30

    We show a versatile method for the preparation of a variety of humidity-responsive actuators based on a single sheet of a hydrogen-bonded, uniaxially aligned liquid crystal polymer network. In this approach, the asymmetry in the molecular trigger in the anisotropic polymer film plays a dominant role leading to programmed deformation events. The material is locally treated with a potassium hydroxide solution to create the asymmetry in the responsiveness toward humidity, which allows to prepare actuators that bend, fold, or curl. PMID:25022765

  9. Vector wind, horizontal divergence, wind stress and wind stress curl from SEASAT-SASS at one degree resolution

    NASA Technical Reports Server (NTRS)

    Pierson, W. J., Jr.; Sylvester, W. B.; Salfi, R. E.

    1984-01-01

    Conventional data obtained in 1983 are contrasted with SEASAT-A scatterometer and scanning multichannel microwave radiometer (SMMR) data to show how observations at a single station can be extended to an area of about 150,000 square km by means of remotely sensed data obtained in nine minutes. Superobservations at a one degree resolution for the vector winds were estimated along with their standard deviations. From these superobservations, the horizontal divergence, vector wind stress, and the curl of the wind stress can be found. Weather forecasting theory is discussed and meteorological charts of the North Pacific Ocean are presented. Synoptic meteorology as a technique is examined.

  10. Leaf absorbance and photosynthesis

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    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.

  11. Leaf-to-leaf distances in Catalan tree graphs

    E-print Network

    Andrew M. Goldsborough; Jonathan M. Fellows; Matthew Bates; S. Alex Rautu; George Rowlands; Rudolf A. Römer

    2015-03-02

    We study the average leaf-to-leaf path lengths on ordered Catalan tree graphs with $n$ nodes and show that these are equivalent to the average length of paths starting from the root node. We give an explicit analytic formula for the average leaf-to-leaf path length as a function of separation of the leaves and study its asymptotic properties. At the heart of our method is a strategy based on an abstract graph representation of generating functions which we hope can be useful also in other contexts.

  12. 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

    Ghanim, Murad

    2014-06-24

    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

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

    PubMed Central

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

    2009-01-01

    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

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

    PubMed

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

    2015-02-01

    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

  15. Leaf development: a cellular perspective

    PubMed Central

    Kalve, Shweta; De Vos, Dirk; Beemster, Gerrit T. S.

    2014-01-01

    Through its photosynthetic capacity the leaf provides the basis for growth of the whole plant. In order to improve crops for higher productivity and resistance for future climate scenarios, it is important to obtain a mechanistic understanding of leaf growth and development and the effect of genetic and environmental factors on the process. Cells are both the basic building blocks of the leaf and the regulatory units that integrate genetic and environmental information into the developmental program. Therefore, to fundamentally understand leaf development, one needs to be able to reconstruct the developmental pathway of individual cells (and their progeny) from the stem cell niche to their final position in the mature leaf. To build the basis for such understanding, we review current knowledge on the spatial and temporal regulation mechanisms operating on cells, contributing to the formation of a leaf. We focus on the molecular networks that control exit from stem cell fate, leaf initiation, polarity, cytoplasmic growth, cell division, endoreduplication, transition between division and expansion, expansion and differentiation and their regulation by intercellular signaling molecules, including plant hormones, sugars, peptides, proteins, and microRNAs. We discuss to what extent the knowledge available in the literature is suitable to be applied in systems biology approaches to model the process of leaf growth, in order to better understand and predict leaf growth starting with the model species Arabidopsis thaliana. PMID:25132838

  16. Genetic relationships in Cucurbita pepo (pumpkin, squash, gourd) as viewed with high frequency oligonucleotide–targeting active gene (HFO–TAG) markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucurbita pepo is a highly diverse, economically important member of the Cucurbitaceae. C. pepo encompasses hundreds of cultivars of pumpkins, squash, and gourds. Although C. pepo has been scrutinized with various types of DNA markers, the relationships among the cultivar-groups of C. pepo subsp. p...

  17. Discovery of a new genotype of Squash mosaic virus through deep sequencing of small RNAs and development of a qRT-PCR for broad spectrum detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Squash mosaic virus (SqMV), a seed-borne virus belonging to the genus Commovirus in the family Comoviridae, could cause a serious yield loss on cucurbit crops worldwide. SqMV has a bipartite single-stranded ribonucleic acid (RNA) genome (RNA-1 and RNA-2) encapsidated separately with two capsid prote...

  18. The cystine knot of a squash-type protease inhibitor as a structural scaffold for Escherichia coli cell surface display of conformationally constrained peptides

    Microsoft Academic Search

    Andreas Christmann; Kerstin Walter; Alexander Wentzel; Ralph Kratzner; Harald Kolmar

    1999-01-01

    The Ecballium elaterium trypsin inhibitor II (EETI-II), a member of the squash family of protease inhibitors, is composed of 28 amino acid residues and is a potent inhibitor of trypsin. Its compact structure is defined by a triple- stranded antiparallel b-sheet, which is held together by three intramolecular disulfide bonds forming a cystine knot. In order to explore the potential

  19. 392291-VDR, a watermelon germplasm line with resistance to Squash vein yellowing virus (SqVYV)-caused watermelon vine decline (WVD)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    392291-VDR (vine decline resistant) is a watermelon (Citrullus lanatus var. lanatus) germplasm line having resistance to watermelon vine decline (WVD) caused by the whitefly transmitted Squash vein yellowing virus (SqVYV). The line is derived from the U.S. Plant Introduction (PI) 392291, after succ...

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

    E-print Network

    Verroust-Blondet, Anne

    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

  1. 7 CFR 29.6022 - Leaf scrap.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  2. 7 CFR 29.6023 - Leaf structure.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  3. 7 CFR 29.2529 - Leaf scrap.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  4. 7 CFR 29.2529 - Leaf scrap.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  5. 7 CFR 29.6022 - Leaf scrap.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  6. 7 CFR 29.2529 - Leaf scrap.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  7. 7 CFR 29.6022 - Leaf scrap.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  8. 7 CFR 29.6023 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  9. 7 CFR 29.6023 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  10. The artificial leaf.

    PubMed

    Nocera, Daniel G

    2012-05-15

    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

  11. Wheat Curl Mite and Wheat Streak Mosaic Virus Spread from Volunteer Wheat Figure 2. Spectral profiles at three points identified in Figure

    E-print Network

    Nebraska-Lincoln, University of

    Wheat Curl Mite and Wheat Streak Mosaic Virus Spread from Volunteer Wheat Figure 2. Spectral Management Information Technologies (CALMIT) (apeters@calmit.unl.edu) Background: Wheat streak mosaic (WSM) is the most severe disease of winter wheat in the Great Plains. Estimates indicate WSM causes an average loss

  12. 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...

  13. 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...

  14. 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...

  15. The worldwide leaf economics spectrum

    Microsoft Academic Search

    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

    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

  16. Landscape, kinetics, paths and statistics of curl flux, coherence, entanglement and energy transfer in non-equilibrium quantum systems

    NASA Astrophysics Data System (ADS)

    Zhang, Zhedong; Wang, Jin

    2015-04-01

    We develop a population and flux landscape theory for general non-equilibrium quantum systems. We illustrate our theory by modelling the quantum transport of donor-acceptor energy transfer. We find two driving forces for the non-equilibrium quantum dynamics. The symmetric part of the driving force corresponds to the population landscape contribution which mainly governs the equilibrium part of dynamics while the anti-symmetric part of the driving force generates the non-equilibrium curl quantum flux which leads to the detailed-balance-breaking and time-irreversibility. The multi-loop structure of the flux emerges forms the flux-landscape. We study the trend of changes in population and flux-landscape with respect to the voltage (temperature difference induced by environments) and electronic coupling. Improving the voltage and electronic coupling in general facilitates the quantum transport by reducing the population landscape barriers between major states and increasing the mean value of the flux. A limit-cycle mode emerges when the underlying flux-landscape becomes funnelled with a significant gap between the largest flux loop and the rest of them. On the kinetic level, we find that multiple kinetic paths between quantum states emerge and illustrate the interference effects. The degree of interference is determined by the landscape and flux. Furthermore, we quantify kinetic rate which strongly correlates with the population landscape and flux. For quantum transport, we demonstrate that as the coherence or the quantum entanglement is enhanced, the flux and energy transfer efficiency are increased. Finally it is surprising that the non-equilibriumness quantified by voltage has a non-trivial contribution on strengthening the entanglement, which is attributed to the non-local feature of the quantum curl flux.

  17. Polarisation dependence of the squash mode in the extreme low frequency vibrational region of single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Shen, Y.; Quirke, N.; Zerulla, D.

    2015-05-01

    There is considerable interest in the vibrational modes of carbon nanotubes as they can be used to determine interaction potentials. In particular, theory predicts the appearance of so called squash modes (SMs, with E2g symmetry representation) at very low frequencies. These SMs are expected to be extremely sensitive to environmental changes and thus ideal as nanoscale probes. Here, we report clear experimental evidence for the existence of SMs of ordered, dry, single walled carbon nanotube (SWNT) arrays with peaks as close as 18 cm-1 to the laser excitation. Furthermore, we confirm the theoretical predictions regarding the angular and polarisation dependent variations of the SM's intensity with respect to the excitation. Additionally, using both SM and radial breathing mode data, we unambiguously assign the chirality and diameter of the SWNTs in our sample.

  18. Leaf hydraulics II: vascularized tissues.

    PubMed

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

    2014-01-01

    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

  19. 7 CFR 29.1028 - Leaf.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  20. 7 CFR 29.2528 - Leaf.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  1. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  2. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  3. 7 CFR 29.1028 - Leaf.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  4. Very Sparse Leaf Languages Lance Fortnow

    E-print Network

    Fortnow, Lance

    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

  5. 7 CFR 29.3528 - Leaf surface.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Leaf surface. 29.3528 Section 29...and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to some...

  6. 7 CFR 29.3033 - Leaf.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  7. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  8. 7 CFR 29.3033 - Leaf.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  9. Very Sparse Leaf Languages # Lance Fortnow +

    E-print Network

    Fortnow, Lance

    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

  10. 7 CFR 29.3525 - Leaf.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  11. 7 CFR 29.3033 - Leaf.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  12. 7 CFR 29.2528 - Leaf.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  13. 7 CFR 29.2528 - Leaf.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  14. 7 CFR 29.1028 - Leaf.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  15. 7 CFR 29.3525 - Leaf.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  16. 7 CFR 29.3528 - Leaf surface.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Leaf surface. 29.3528 Section 29...and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to some...

  17. 7 CFR 29.3528 - Leaf surface.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Leaf surface. 29.3528 Section 29...and Foreign Type 95) § 29.3528 Leaf surface. The roughness or smoothness of the web or lamina of a tobacco leaf. Leaf surface is affected to some...

  18. 7 CFR 29.3525 - Leaf.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  19. Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf

    PubMed Central

    Simonin, Kevin A.; Burns, Emily; Choat, Brendan; Barbour, Margaret M.; Dawson, Todd E.; Franks, Peter J.

    2015-01-01

    Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (??stem–leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO2 concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO2 concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO2 on g s. The positive relationship between k leaf and E minimized variation in ??stem–leaf. This enables leaves to minimize variation in ?leaf and maximize g s and CO2 assimilation rate over the diurnal course of evaporative demand. PMID:25547915

  20. PLANT SPECIES RECOGNITION USING SPATIAL CORRELATION BETWEEN THE LEAF MARGIN AND THE LEAF SALIENT POINTS

    E-print Network

    Paris-Sud XI, Université de

    PLANT SPECIES RECOGNITION USING SPATIAL CORRELATION BETWEEN THE LEAF MARGIN AND THE LEAF SALIENT by the plant leaves. More precisely, we consider two sources of information: the leaf margin and the leaf salient points. We investigate two shape context based descriptors: the first one describes the leaf

  1. Leaf-wax n-alkanes record the plantwater environment at leaf ush

    E-print Network

    Tipple, Brett

    Leaf-wax n-alkanes record the plant­water environment at leaf ush Brett J. Tipple1 , Melissa A, UT, and approved December 26, 2012 (received for review August 13, 2012) Leaf-wax n-alkanes 2 H/1 H the 2 H values of leaf-wax n-alkanes and of stem, leaf, stream, and atmospheric waters throughout

  2. Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf.

    PubMed

    Simonin, Kevin A; Burns, Emily; Choat, Brendan; Barbour, Margaret M; Dawson, Todd E; Franks, Peter J

    2015-03-01

    Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (??stem-leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO? concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO? concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO? on g s. The positive relationship between k leaf and E minimized variation in ??stem-leaf. This enables leaves to minimize variation in ?leaf and maximize g s and CO? assimilation rate over the diurnal course of evaporative demand. PMID:25547915

  3. Changes in leaf hydraulic conductance correlate with leaf vein embolism in Cercis siliquastrum L

    Microsoft Academic Search

    Andrea Nardini; Sebastiano Salleo; Fabio Raimondo

    2003-01-01

    The impact of xylem cavitation and embolism on leaf ( K leaf) and stem ( K stem) hydraulic conductance was measured in current-year shoots of Cercis siliquastrum L. (Judas tree) using the vacuum chamber technique. K stem decreased at leaf water potentials (? L) lower than -1.0 MPa, while K leaf started to decrease only at ? L L K leaf

  4. Why do leaf-tying caterpillars abandon their leaf ties?

    PubMed Central

    Sliwinski, Michelle

    2013-01-01

    Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats), but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm2 leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently abandon their leaf tie due to food limitation and interactions with other caterpillars, but this is a costly behavior. PMID:24109557

  5. What determines a leaf's shape?

    PubMed

    Dkhar, Jeremy; Pareek, Ashwani

    2014-01-01

    The independent origin and evolution of leaves as small, simple microphylls or larger, more complex megaphylls in plants has shaped and influenced the natural composition of the environment. Significant contributions have come from megaphyllous leaves, characterized usually as flat, thin lamina entrenched with photosynthetic organelles and stomata, which serve as the basis of primary productivity. During the course of evolution, the megaphylls have attained complexity not only in size or venation patterns but also in shape. This has fascinated scientists worldwide, and research has progressed tremendously in understanding the concept of leaf shape determination. Here, we review these studies and discuss the various factors that contributed towards shaping the leaf; initiated as a small bulge on the periphery of the shoot apical meristem (SAM) followed by asymmetric outgrowth, expansion and maturation until final shape is achieved. We found that the underlying factors governing these processes are inherently genetic: PIN1 and KNOX1 are indicators of leaf initiation, HD-ZIPIII, KANADI, and YABBY specify leaf outgrowth while ANGUSTIFOLIA3 and GROWTH-REGULATING FACTOR5 control leaf expansion and maturation; besides, recent research has identified new players such as APUM23, known to specify leaf polarity. In addition to genetic control, environmental factors also play an important role during the final adjustment of leaf shape. This immense amount of information available will serve as the basis for studying and understanding innovative leaf morphologies viz. the pitchers of the carnivorous plant Nepenthes which have evolved to provide additional support to the plant survival in its nutrient-deficient habitat. In hindsight, formation of the pitcher tube in Nepenthes might involve the recruitment of similar genetic mechanisms that occur during sympetaly in Petunia. PMID:25584185

  6. Chemical synthesis of new trypsin, chymotrypsin and elastase inhibitors by amino-acid substitutions in a trypsin inhibitor from squash seeds (CMTI III).

    PubMed

    Rolka, K; Kupryszewski, G; Ragnarsson, U; Otlewski, J; Krokoszynska, I; Wilusz, T

    1991-01-01

    Five new analogues of squash trypsin inhibitor CMTI III were obtained by the solid-phase method, exhibiting antitrypsin, antichymotrypsin or antielastase activity. Modification in the reactive site region changes dramatically the specificity, whereas substitution in non-contact positions facilitates the refolding of the reduced form of the peptides and does not have a significant influence on the association equilibrium constants of the inhibitor analogues with cognate enzymes. PMID:2039608

  7. Cucumber mosaic virus 2a polymerase and 3a movement proteins independently affect both virus movement and the timing of symptom development in zucchini squash

    Microsoft Academic Search

    Seung Kook Choi; Peter Palukaitis; Byoung Eun Min; Mi Yeon Lee; Jang Kyung Choi; Ki Hyun Ryu

    2005-01-01

    The basis for differences in the timing of systemic symptom elicitation in zucchini squash between a pepper strain of Cucumber mosaic virus (Pf-CMV) and a cucurbit strain (Fny-CMV) was analysed. The difference in timing of appearance of systemic symptoms was shown to map to both RNA 2 and RNA 3 of Pf-CMV, with pseudorecombinant viruses containing either RNA 2 or

  8. NON-DESTRUCTIVE ASSESSMENT OF ARUNDO DONAX (POACEAE) LEAF QUALITY.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf quality information (i.e., leaf C content, leaf N content, leaf C:N ratio) is especially useful for understanding plant-herbivore interactions and may be important in developing control methods for the invasive riparian plant Arundo donax L. We measured leaf C content, leaf N content, leaf C:N ...

  9. 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

    Varzakas, Theodoros H; Arvanitoyannis, Ioannis S

    2007-01-01

    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

  10. System technology and test of CURL 10, a 10 kV, 10 MVA resistive high-Tc superconducting fault current limiter

    Microsoft Academic Search

    Ronald Kreutz; Joachim Bock; Frank Breuer; Klaus-Peter Juengst; Martin Kleimaier; Hans-Udo Klein; Detlef Krischel; Mathias Noe; Ralph Steingass; Karl-Heinz Weck

    2005-01-01

    A full scale three-phase resistive high-Tc superconducting fault current limiter (SCFCL) designed for 10 kV, 10 MVA, has been developed, manufactured, and tested within a publicly funded German project called CURL 10. The device is based on 90 bifilar coils of MCP BSCCO-2212 bulk material. The operating temperature of 66 K is achieved by cooling of liquid nitrogen using two

  11. Upwelling induced by the frictional stress curl and vertical squeezing of the vortex tube over a submerged valley in the East China Sea

    NASA Astrophysics Data System (ADS)

    Liu, Zhiqiang; Gan, Jianping

    2015-04-01

    We conducted a process-oriented modeling study to investigate the characteristics and dynamics of the prominent upwelling over a vast submerged valley in the East China Sea (ECS). The valley is inversely funnel-shaped with the west bank and the east bank oriented in the north-south direction. A cross-bank upward transport occurred along the west bank. It intensified northward and peaked around the head of the valley. An along-bank southward pressure gradient force (PGF) formed the cross-bank geostrophic transport for the upwelling over the valley. The PGF reached its maxima at the head of the valley. Our momentum and vorticity dynamic analyses revealed that a bottom stress curl mainly contributed the PGF along the west bank. At the same time, both the bottom stress curl and the nonlinear vorticity advection contributed to the PGF around the head. The bottom stress curl was due to the bottom shear vorticity of the coastal current and the curvature vorticity around the head. The nonlinear vorticity advection formed because of the vertical squeezing of vortex tube as the current flowed over the valley. The nonlinearity mainly affected the PGF around the head, whereas the bottom stress curl contributed to the PGF over the entire valley. The ratio of the nonlinear to frictional contributions to the PGF increased as the coastal current intensified. Our study demonstrates that the PGF that drives the upwelling over the valley is the combined result of the nonlinearity due to vertical squeezing of vortex tube and bottom frictional effects.

  12. Endoplasmic reticulum-targeted GFP reveals ER remodeling in Mesorhizobium-treated Lotus japonicus root hairs during root hair curling and infection thread formation.

    PubMed

    Perrine-Walker, F M; Kouchi, H; Ridge, R W

    2014-07-01

    The endoplasmic reticulum (ER) of the model legume Lotus japonicus was visualized using green fluorescent protein (GFP) fused with the KDEL sequence to investigate the changes in the root hair cortical ER in the presence or absence of Mesorhizobium loti using live fluorescence imaging. Uninoculated root hairs displayed dynamic forms of ER, ranging from a highly condensed form to an open reticulum. In the presence of M. loti, a highly dynamic condensed form of the ER linked with the nucleus was found in deformed, curled, and infected root hairs, similar to that in uninoculated and inoculated growing zone I and II root hairs. An open reticulum was primarily found in mature inoculated zone III root hairs, similar to that found in inactive deformed/curled root hairs and infected root hairs with aborted infection threads. Co-imaging of GFP-labeled ER with light transmission demonstrated a correlation between the mobility of the ER and other organelles and the directionality of the cytoplasmic streaming in root hairs in the early stages of infection thread formation and growth. ER remodeling in root hair cells is discussed in terms of possible biological significance during root hair growth, deformation/curling, and infection in the Mesorhizobium-L. japonicus symbiosis. PMID:24337802

  13. Non-Euclidean stress-free configuration of arteries accounting for curl of axial strips sectioned from vessels.

    PubMed

    Takamizawa, Keiichi; Nakayama, Yasuhide

    2013-11-01

    It is well known that arteries are subject to residual stress. In earlier studies, the residual stress in the arterial ring relieved by a radial cut was considered in stress analysis. However, it has been found that axial strips sectioned from arteries also curled into arcs, showing that the axial residual stresses were relieved from the arterial walls. The combined relief of circumferential and axial residual stresses must be considered to accurately analyze stress and strain distributions under physiological loading conditions. In the present study, a mathematical model of a stress-free configuration of artery was proposed using Riemannian geometry. Stress analysis for arterial walls under unloaded and physiologically loaded conditions was performed using exponential strain energy functions for porcine and human common carotid arteries. In the porcine artery, the circumferential stress distribution under physiological loading became uniform compared with that without axial residual strain, whereas a gradient of axial stress distribution increased through the wall thickness. This behavior showed almost the same pattern that was observed in a recent study in which approximate analysis accounting for circumferential and axial residual strains was performed, whereas the circumferential and axial stresses increased from the inner surface to the outer surface under a physiological condition in the human common carotid artery of a two-layer model based on data of other recent studies. In both analyses, Riemannian geometry was appropriate to define the stress-free configurations of the arterial walls with both circumferential and axial residual strains. PMID:24008313

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

    PubMed

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

    2014-01-01

    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

  15. 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.

  16. Biophysical control of leaf temperature

    NASA Astrophysics Data System (ADS)

    Dong, N.; Prentice, I. C.; Wright, I. J.

    2014-12-01

    In principle sunlit leaves can maintain their temperatures within a narrower range than ambient temperatures. This is an important and long-known (but now overlooked) prediction of energy balance theory. Net radiation at leaf surface in steady state (which is reached rapidly) must be equal to the combination of sensible and latent heat exchanges with surrounding air, the former being proportional to leaf-to-air temperature difference (?T), the latter to the transpiration rate. We present field measurements of ?T which confirm the existence of a 'crossover temperature' in the 25-30?C range for species in a tropical savanna and a tropical rainforest environment. This finding is consistent with a simple representation of transpiration as a function of net radiation and temperature (Priestley-Taylor relationship) assuming an entrainment factor (?) somewhat greater than the canonical value of 0.26. The fact that leaves in tropical forests are typically cooler than surrounding air, often already by solar noon, is consistent with a recently published comparison of MODIS day-time land-surface temperatures with air temperatures. Theory further predicts a strong dependence of leaf size (which is inversely related to leaf boundary-layer conductance, and therefore to absolute magnitude of ?T) on moisture availability. Theoretically, leaf size should be determined by either night-time constraints (risk of frost damage to active leaves) or day-time constraints (risk of heat stress damage),with the former likely to predominate - thereby restricting the occurrence of large leaves - at high latitudes. In low latitudes, daytime maximum leaf size is predicted to increase with temperature, provided that water is plentiful. If water is restricted, however, transpiration cannot proceed at the Priestley-Taylor rate, and it quickly becomes advantageous for plants to have small leaves, which do not heat up much above the temperature of their surroundings. The difference between leaf and air temperature is generally neglected in terrestrial ecosystem and carbon cycle models. This is a significant omission that could lead to an over-estimation of the heat-stress vulnerability of carbon uptake in the wet tropics. Leaf energy balance theory is well established, and should be included in the next generation of models.

  17. Use of visible and near-infrared spectroscopy for predicting antioxidant compounds in summer squash (Cucurbita pepo ssp pepo).

    PubMed

    Blanco-Díaz, María Teresa; Del Río-Celestino, Mercedes; Martínez-Valdivieso, Damián; Font, Rafael

    2014-12-01

    The food industry and plant breeding programmes require fast, clean and low-cost screening techniques for nutritional compounds determination in food matrices. This is the first report on the study of the potential of near-infrared spectroscopy (NIRS) for the prediction of antioxidant compounds in summer squash tissues collected since 2009-2012. Modified partial least-squares (MPLS) regression was used to correlate spectral information and the different antioxidant compounds in the samples. The coefficients of determination in the external validation (r(2)ev) obtained were for ascorbic acid (0.77 and 0.86), chlorophyll a (0.79 and 0.66), chlorophyll b (0.86 and 0.79) and total phenolic compounds (0.65 and 0.68) in exocarp and mesocarp tissues, respectively, supporting that NIRS is able to predict in a rapid way these components for screening purposes. Major wavelengths influencing the calibration equations showed that chromophores as well as fibre components of the fruits highly participated in developing the NIR equations. PMID:24996338

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

    PubMed Central

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

    2013-01-01

    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

  19. Serine proteinase from Cucurbita ficifolia seed; purification, properties, substrate specificity and action on native squash trypsin inhibitor (CMTI I).

    PubMed

    Dryjanski, M; Otlewski, J; Polanowski, A; Wilusz, T

    1990-09-01

    A proteinase was purified from resting seeds of Cucurbita ficifolia by ammonium sulfate fractionation and successive chromatography on CM-cellulose, Sephacryl S-300 and TSK DEAE-2SW (HPLC) columns. Inhibition by DFP and PMSF suggests that the enzyme is a serine proteinase. The apparent molecular mass of this enzyme is ca. 77 kDa. The optimum activity for hydrolysis of casein and Suc-Ala-Ala-Pro-Phe-pNA is around pH 10.5. The following peptide bonds in the oxidized insulin B-chain were hydrolysed by the proteinase: Phe1-Val2, Asn3-Gln4, Gln4-His5, Cya7-Gly8, Glu13-Ala14, Ala14-Leu15, Cya19-Gly20, Pro28-Lys29 and Lys29-Ala30. The proteinase is more selective towards the native squash seed trypsin inhibitor (CMTI I) and primarily cuts off only its N-terminal arginine. The inhibitor devoided of the N-terminal arginine residue is still active against trypsin. PMID:2291813

  20. 7 CFR 28.471 - Below Leaf Grade Cotton.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  1. 7 CFR 28.471 - Below Leaf Grade Cotton.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  2. 7 CFR 28.471 - Below Leaf Grade Cotton.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  3. An Innovative Way to Monitor Leaf Age

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  4. The scaling of leaf area and mass: the cost of light interception increases with leaf size

    E-print Network

    Minnesota, University of

    The scaling of leaf area and mass: the cost of light interception increases with leaf size Rube (specific leaf area, SLA) is a key trait from physiological, ecological and biophysical perspectives. To address whether SLA declines with leaf size, as hypothesized due to increasing costs of support in larger

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

    E-print Network

    Paris-Sud XI, Université de

    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

  6. Relationships between sugarcane leaf hyperspectral reflectance, leaf nitrogen content, and yield components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf spectral reflectance has been used to estimate crop leaf chemical composition and other physiological characters. Leaf reflectance of sugarcane (Saccharum spp.) may be of use in evaluating genotypes. The objectives of this study were: (1) to identify sugarcane genotypic variation in leaf hypers...

  7. Original article Photosynthesis, leaf area and productivity

    E-print Network

    Paris-Sud XI, Université de

    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

  8. 7 CFR 29.2277 - Leaf scrap.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  9. 7 CFR 29.2278 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  10. 7 CFR 29.3526 - Leaf scrap.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  11. 7 CFR 29.2278 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  12. 7 CFR 29.3034 - Leaf scrap.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  13. Leaf Sequencing Algorithms for Segmented Multileaf Collimation

    E-print Network

    Sahni, Sartaj K.

    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

  14. 7 CFR 29.2278 - Leaf structure.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  15. Parameterized Algorithms for Directed Maximum Leaf Problems

    E-print Network

    Krivelevich, Michael

    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

  16. 7 CFR 29.2277 - Leaf scrap.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  17. 7 CFR 29.3034 - Leaf scrap.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  18. 7 CFR 29.2277 - Leaf scrap.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  19. 7 CFR 29.3526 - Leaf scrap.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  20. 7 CFR 29.3034 - Leaf scrap.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  1. 7 CFR 29.3526 - Leaf scrap.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  2. Exobasidium leaf and fruit spot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the past five or so years blueberry growers in south Mississippi have discovered the disease Exobasidium leaf and fruit spot on some of their blueberry plants. In the past this disease was considered to be of minor importance occurring infrequently on isolated farms. But in recent years it ...

  3. XANTHOMONAS LEAF BLIGHT OF ONION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas leaf blight, caused by the bacterium Xanthomonas axonopodis pv. allii, is a common foliar disease of onion. This extension bulletin presents a review of disease symptomology, etiology, epidemiology, and management. The association of environment, host, and cultural and disease severity ...

  4. Leaf Photosynthesis Under Drought Stress

    Microsoft Academic Search

    Gabriel Cornic; Angelo Massacci

    The photosynthetic apparatus is resistant to drought. Net CO2 uptake of a leaf submitted to a mild desiccation decreases because of stomatal closure. As aresult, CO2 concentration in the chloroplast decreases in plants exposed to water shortage. This drop in the chloroplast CO2 concentration causes: (i) a decrease in photochemical yield of open PS II centers and, consequently, an increase

  5. 7 CFR 29.1162 - Leaf (B Group).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...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...

  6. 7 CFR 29.1162 - Leaf (B Group).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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...

  7. Leaf area dynamics of conifer forests

    SciTech Connect

    Margolis, H.; Oren, R.; Whitehead, D.; Kaufmann, M.R.

    1995-07-01

    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.

  8. A Putative Role for the Tomato Genes DUMPY and CURL3 in Brassinosteroid Biosynthesis and Response1

    Microsoft Academic Search

    Chala V. Koka; R. Eric Cerny; Randy G. Gardner; Takahiro Noguchi; Shozo Fujioka; Suguru Takatsuto; Shigeo Yoshida; Steven D. Clouse

    2000-01-01

    The dumpy (dpy) mutant of tomato (Lycopersicon esculentum Mill.) exhibits short stature, reduced axillary branching, and altered leaf morphology. Application of brassinolide and castasterone res- cued the dpy phenotype, as did C-23-hydroxylated, 6-deoxo inter- mediates of brassinolide biosynthesis. The brassinolide precursors campesterol, campestanol, and 6-deoxocathasterone failed to res- cue, suggesting that dpy may be affected in the conversion of 6-deoxocathasterone

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

    NASA Astrophysics Data System (ADS)

    Ahn, Changhyun; Woo, Kyungsung

    2010-02-01

    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.

  10. The relationship of leaf photosynthetic traits – Vcmax and Jmax – to leaf nitrogen, leaf phosphorus, and specific leaf area: a meta-analysis and modeling study

    PubMed Central

    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

    2014-01-01

    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 (Vcmax) and the maximum rate of electron transport (Jmax). 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 Vcmax and Jmax 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 Vcmax and Jmax 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 Vcmax and Jmax with leaf N, P, and SLA. Vcmax was strongly related to leaf N, and increasing leaf P substantially increased the sensitivity of Vcmax to leaf N. Jmax was strongly related to Vcmax, 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 Jmax to Vcmax coordination that restricts photoinhibition when carboxylation is limiting at the expense of maximizing photosynthetic rates when light is limiting. PMID:25473475

  11. 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

    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

    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

  12. Leaf hydraulic conductance is coordinated with leaf morpho-anatomical traits and nitrogen status in the genus Oryza.

    PubMed

    Xiong, Dongliang; Yu, Tingting; Zhang, Tong; Li, Yong; Peng, Shaobing; Huang, Jianliang

    2015-02-01

    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

  13. Leaf hydraulic conductance is coordinated with leaf morpho-anatomical traits and nitrogen status in the genus Oryza

    PubMed Central

    Xiong, Dongliang; Yu, Tingting; Zhang, Tong; Li, Yong; Peng, Shaobing; Huang, Jianliang

    2015-01-01

    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

  14. LeafJ: An ImageJ Plugin for Semi-automated Leaf Shape Measurement

    PubMed Central

    Mumbach, Maxwell R.; Palmer, Christine M.

    2013-01-01

    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

  15. Perspectives on leaf dorsoventral polarity

    Microsoft Academic Search

    Dóra Szakonyi; Alexis Moschopoulos; Mary E. Byrne

    2010-01-01

    Leaves occur in a vast array of shapes and sizes, with complex diversity contributing to optimization of the principal function\\u000a of photosynthesis. The program of development from a self-renewing stem cell population to a mature leaf has been of interest\\u000a to biologists for years. Many genes involved in this process have been identified, particularly in the model eudicot Arabidopsis,\\u000a so

  16. Curling And Inertia

    NSDL National Science Digital Library

    2010-01-01

    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.

  17. Effects of stomatal density and leaf water content on the ¹?O enrichment of leaf water.

    PubMed

    Larcher, Leticia; Hara-Nishimura, Ikuko; Sternberg, Leonel

    2015-04-01

    Leaf water isotopic composition is imprinted in several biomarkers of interest and it is imperative that we understand the isotopic enrichment of leaf water. Here, we test the effect of stomatal density and leaf water content on the oxygen isotopic composition of leaf water in transgenic Arabidopsis plants expressing different stomatal densities, and several other species showing a range of stomatal density. We grew Arabidopsis plants hydroponically and collected other species in the field. Stomatal density and leaf water content were determined for each plant. We measured transpiration and extracted leaf water for isotopic determination. Using these measurements and the current leaf water isotope model, we calculated several of the parameters related to leaf water isotopic enrichment. High stomatal density promoted leaf water isotope enrichment. No conclusion, however, can be drawn regarding the effect of leaf water content on leaf water isotope enrichment. Factors such as transpiration might mask the effect of stomatal density on leaf water isotopic enrichment. We propose a method by which stomatal density can be incorporated in the current Peclet model of leaf water isotope enrichment. These findings have important applications in the use of plant-based metabolic proxies in paleoclimate studies. PMID:25408145

  18. High-resolution structures of three new trypsin-squash-inhibitor complexes: a detailed comparison with other trypsins and their complexes.

    PubMed

    Helland, R; Berglund, G I; Otlewski, J; Apostoluk, W; Andersen, O A; Willassen, N P; Smalås, A O

    1999-01-01

    An anionic trypsin from Atlantic salmon and bovine trypsin have been complexed with the squash-seed inhibitors, CMTI-I (Cucurbita maxima trypsin inhibitor I, P1 Arg) and CPTI-II (Cucurbita pepo trypsin inhibitor II, P1 Lys). The crystal structures of three such complexes have been determined to 1.5-1.8 A resolution and refined to crystallographic R factors ranging from 17.6 to 19.3%. The two anionic salmon-trypsin complexes (ST-CPTI and ST-CMTI) and the bovine-trypsin complex (BT-CPTI) have been compared to other trypsin-inhibitor complexes by means of general structure and primary and secondary binding features. In all three new structures, the primary binding residue of the inhibitor binds to trypsin in the classical manner, but with small differences in the primary and secondary binding patterns. Lysine in CPTI-II binds deeper in the specificity pocket of bovine trypsin than lysine in other known lysine-bovine-trypsin complexes, and anionic salmon trypsin lacks some of the secondary binding interactions found in the complexes formed between squash inhibitors and bovine trypsin. The ST-CMTI complex was formed from the reactive-site-cleaved form of the inhibitor. However, well defined electron density was observed for the P1-P1' peptide bond, together with a hydrogen-bonding pattern virtually identical to those of all serine-protease-protein-inhibitor complexes, indicating a resynthesis of the scissile bond. PMID:10089404

  19. Leaf endophyte load influences fungal garden development in leaf-cutting ants

    E-print Network

    Bermingham, Eldredge

    their symbiont fungus. The ants' fungal symbiont then partially degrades the leaf material, converting leaf; in the latter endophyte composition changed * Correspondence: svanbael@tulane.edu 1 Department of Ecology

  20. GELATION OF ALFALFA SOLUBLE LEAF PROTEINS

    Microsoft Academic Search

    B. P. Lamsal; R. G. Koegel; S. Gunasekaran

    Various alfalfa soluble leaf protein concentrates were prepared by freeze-drying acid-precipitated proteins (pH 3.5), resolubilized proteins (pH 7), and membrane-concentrated clarified alfalfa juice. Dilute leaf protein solutions were prepared by dissolving these concentrates in water. Storage modulus (G ) of soluble leaf protein solutions as they gel was monitored with a cone-and-plate probe during temperature sweep from 25°C to 90°C

  1. 7 CFR 28.467 - Leaf Grade 7.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  2. 7 CFR 28.466 - Leaf Grade 6.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  3. 7 CFR 28.464 - Leaf Grade 4.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  4. 7 CFR 28.462 - Leaf Grade 2.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  5. 7 CFR 28.463 - Leaf Grade 3.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  6. 7 CFR 28.462 - Leaf Grade 2.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  7. 7 CFR 28.463 - Leaf Grade 3.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  8. 7 CFR 28.466 - Leaf Grade 6.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  9. 7 CFR 28.465 - Leaf Grade 5.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  10. 7 CFR 28.466 - Leaf Grade 6.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  11. 7 CFR 28.464 - Leaf Grade 4.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  12. 7 CFR 28.461 - Leaf Grade 1.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  13. 7 CFR 28.461 - Leaf Grade 1.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  14. 7 CFR 28.461 - Leaf Grade 1.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  15. 7 CFR 28.464 - Leaf Grade 4.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  16. 7 CFR 28.465 - Leaf Grade 5.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  17. 7 CFR 28.462 - Leaf Grade 2.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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...

  18. 7 CFR 28.467 - Leaf Grade 7.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  19. 7 CFR 28.465 - Leaf Grade 5.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  20. 7 CFR 28.463 - Leaf Grade 3.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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...

  1. 7 CFR 28.467 - Leaf Grade 7.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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...

  2. Influence of leaf water status on leaf area index and leaf nitrogen concentration inversion of wheat canopy

    NASA Astrophysics Data System (ADS)

    Zhao, Chunjiang; Wang, Jihua; Huang, Wenjiang; Liu, Liangyun

    2005-01-01

    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.

  3. 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 Agriculture...STANDARDS AND STANDARD CONTAINER REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade...

  4. 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 Agriculture...STANDARDS AND STANDARD CONTAINER REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade...

  5. Leaf element concentrations of terrestrial plants across China are

    E-print Network

    Slik, Ferry

    extracted from publications. The links between envi- ronmental variables, taxonomy and leaf elements wereRESEARCH PAPER Leaf element concentrations of terrestrial plants across China are influenced cycles of terrestrial eco- systems are strongly affected by leaf element concentrations. Understanding

  6. LSD: a leaf senescence database

    PubMed Central

    Liu, Xiaochuan; Li, Zhonghai; Jiang, Zhiqiang; Zhao, Yi; Peng, Jinying; Jin, Jinpu; Guo, Hongwei; Luo, Jingchu

    2011-01-01

    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

  7. Wheat Leaf Rust Caused by Puccinia triticina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf rust, caused by Puccinia triticina, is the most common rust disease of wheat. The fungus is an obligate parasite capable of producing infectious urediniospores as long as the host remains healthy. Urediniospores can be wind-disseminated hundreds of kilometers and may result in wheat leaf rust e...

  8. 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 ...

  9. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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, and 51 FR 25027,...

  10. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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, and 51 FR 25027,...

  11. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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, and 51 FR 25027,...

  12. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...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, and 51 FR 25027,...

  13. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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, and 51 FR 25027,...

  14. Automobile leaf springs from composite materials

    Microsoft Academic Search

    H. A. Al-Qureshi

    2001-01-01

    The automobile industry has shown increased interest in the replacement of steel springs with fiberglass reinforced composite leaf springs. Therefore, the aim of this paper is to present a general study on the analysis, design and fabrication of composite springs. From this viewpoint, the suspension spring of a compact car, “a jeep” was selected as a prototype.A single leaf, variable

  15. Photovoltaic Leaf Area Meter Development and Testing

    Microsoft Academic Search

    C. Igathinathane; B. Chennakesavulu; K. Manohar; A. R. Womac; L. O. Pordesimo

    2008-01-01

    Photovoltaic (PV) panel was used to develop a simple and practical leaf area meter. Components of the developed PV leaf area meter include a PV panel as sensor, a wooden cabinet as enclosure, a flashlight as light source, and a commercial digital multimeter for voltage measurement. The principle of projected area measurement is the voltage generated by the PV panel

  16. 7 CFR 29.1029 - Leaf scrap.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 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....

  17. 7 CFR 29.1029 - Leaf scrap.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 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....

  18. 7 CFR 29.1029 - Leaf scrap.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 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....

  19. The red edge of plant leaf reflectance

    Microsoft Academic Search

    D. N. H. Horler; M. Dockray; J. Barber

    1983-01-01

    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

  20. Inferring climate from angiosperm leaf venation networks.

    PubMed

    Blonder, Benjamin; Enquist, Brian J

    2014-10-01

    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

  1. Physiological, anatomical and leaf hydraulic effects on leaf water ?18O enrichment in different plant species

    NASA Astrophysics Data System (ADS)

    Kahmen, A.; Arndt, S. K.; Dawson, T. E.

    2007-12-01

    Stable oxygen isotope ratios (?18O) of plant and source waters are valuable tools in the analysis of water and carbon fluxes at leaf, plant, and ecosystem scales. Recent improvements in mechanistic models have significantly advanced the understanding of isotopic leaf water enrichment, which is an important source of ?18O variability in plants and ecosystems. However, the marked variability in leaf water ?18O values that have been reported for different plant species hampers efforts to interpret and then apply data on leaf water ?18O values for studies conducted at the ecosystem scale. To improve the understanding and application of ?18O values in leaf water, we tested the interplay of physiological, morphological, anatomical and leaf hydraulic properties as drivers of leaf water ?18O values across 17 Eucalyptus species growing in a common garden. We observed large differences in leaf water ?18O across the 17 species. These differences were only partly driven by physiological and leaf morphological differences across species. A sensitivity analysis using state-of-the-art leaf water enrichment models showed that the parameter - effective path length - (L) is of critical importance for the variability of leaf water ?18O across different species. The data show that L can be related to a suite of leaf properties that include physiology, anatomy and hydraulics. Consequently, consideration of leaf properties will significantly improve the interpretation of ?18O values in leaf water across different plant species and will therefore help in the application of ?18O values in carbon and water cycle assessments at both the plant and the ecosystem scale.

  2. Specific leaf area and leaf nitrogen concentration in annual and perennial grass species growing in Mediterranean old-fields

    Microsoft Academic Search

    E. Garnier; P. Cordonnier; J.-L. Guillerm; L. Sonié

    1997-01-01

    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

  3. FPGA Implementation of SQUASH

    Microsoft Academic Search

    Jean-Jacques Quisquater

    Passive RFID tags are devices with very poor computational capability. How- ever an increasing number of applications require authentication of the tag. For this purpose, a simple solution is to use a challenge-response protocol. For exam- ple, the reader can send a random challenge R and the tag responds H(R S), where S is a secret known by the reader

  4. A model for leaf initiation

    PubMed Central

    Abraham-Shrauner, Barbara; Pickard, Barbara G

    2011-01-01

    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

  5. Localization of Boron in Cell Walls of Squash and Tobacco and Its Association with Pectin (Evidence for a Structural Role of Boron in the Cell Wall).

    PubMed Central

    Hu, H.; Brown, P. H.

    1994-01-01

    B deficiency results in a rapid inhibition of plant growth, and yet the form and function of B in plants remains unclear. In this paper we provide evidence that B is chemically localized and structurally important in the cell wall of plants. The localization and chemical fractionation of B was followed in squash plants (Curcurbita pepo L.) and cultured tobacco cells (Nicotiana tabacum) grown in B-replete or B-deficient medium. As squash plants and cultured tobacco cells became deficient, an increasingly large proportion of cellular B was found to be localized in the cell wall. Cytoplasmic B concentrations were reduced to essentially zero as plants became deficient, whereas cell wall B concentration remained at or above 10 [mu]g B/g cell wall dry weight in all experiments. Chemical and enzymic fractionation studies suggest that the majority of cell B is associated with pectins within the cell wall. Physical analysis of B-deficient tissue indicates that cell wall plastic extensibility is greatly reduced under B deficiency, and anatomical observations indicate that B deficiency impairs normal cell elongation in growing plant tissue. In plants in which B deficiency had inhibited all plant growth, tissues remained green and did not show any additional visible symptoms for at least 1 week with no additional B. This occurred even though cytoplasmic B had been reduced to extremely low levels (<0.2 [mu]g/g). This suggests that B in these species is largely associated with the cell wall and that any cytoplasmic role for B is satisfied by very low concentrations of B. The localization of B in the cell wall, its association with cell wall pectins, and the contingent effects of B on cell wall extensibility suggest that B plays a critical, although poorly defined, role in the cell wall structure of higher plants. PMID:12232235

  6. Investigating differences in the root to shoot transfer and xylem sap solubility of organic compounds between zucchini, squash and soybean using a pressure chamber method.

    PubMed

    Garvin, Naho; Doucette, William J; White, Jason C

    2015-07-01

    A pressure chamber method was used to examine differences in the root to shoot transfer and xylem sap solubility of caffeine (log Kow=-0.07), triclocarban (log Kow=3.5-4.2) and endosulfan (log Kow=3.8-4.8) for zucchini (cucurbita pepo ssp pepo), squash (cucurbita pepo ssp ovifera), and soybean (glycine max L.). Transpiration stream concentration factors (TSCF) for caffeine (TSCF=0.8) were statistically equivalent for all plant species. However, for the more hydrophobic endosulfan and triclocarban, the TSCF values for zucchini (TSCF=0.6 and 0.4, respectively) were 3 and 10 times greater than the soybean and squash (TSCF=0.2 and 0.05, respectively). The difference in TSCF values was examined by comparing the measured solubilities of caffeine, endosulfan and triclocarban in deionized water to those in soybean and zucchini xylem saps using a modified shake flask method. The measured solubility of organic contaminants in xylem sap has not previously been reported. Caffeine solubilities in the xylem saps of soybean and zucchini were statistically equal to deionized water (21500mgL(-1)) while endosulfan and triclocarban solubilities in the zucchini xylem sap were significantly greater (0.43 and 0.21mgL(-1), respectively) than that of the soybean xylem sap (0.31 and 0.11mgL(-1), respectively) and deionized water (0.34 and 0.11mgL(-1), respectively). This suggests that the enhanced root to shoot transfer of hydrophobic organics reported for zucchini is partly due to increased solubility in the xylem sap. Further xylem sap characterization is needed to determine the mechanism of solubility enhancement. PMID:25537866

  7. Low genetic diversity of Squash vein yellowing virus in wild and cultivated cucurbits in the U.S. suggests a recent introduction.

    PubMed

    Webster, Craig G; Adkins, Scott

    2012-02-01

    Squash vein yellowing virus (SqVYV) isolates were collected from cultivated and weedy cucurbits representing major hosts and locations in the U.S. and analyzed to better understand the diversity and population structure. No differences in symptoms were observed in field-collected isolate source plants or subsequently inoculated greenhouse plants, and the complete genome of an SqVYV isolate from a wild cucurbit host (smellmelon, Cucumis melo var. dudaim) was highly similar (99.4% nucleotide identity, 99.3% amino acid identity) to the previously published type isolate from squash. Although analysis of the coat protein (CP) and two serine proteases (P1a and P1b) sequences for 41 isolates showed little diversity across seven years of sampling, it revealed two distinct groups of SqVYV isolates with low intra-group diversity. Our analyses also suggested that recombination had occurred between SqVYV isolates, similar to other ipomoviruses. Selection pressures on the genome regions analyzed were negative indicating purifying selection was occurring. The magnitude of negative selection in SqVYV was consistent with what has been reported for other ipomoviruses, and was greatest for the CP and least for the P1b. The observed genetic diversity was similar to that reported for Cucumber vein yellowing virus but less than that reported for Sweet potato mild mottle virus, Cassava brown streak virus and Ugandan cassava brown streak virus. Collectively, these results indicate that the current U.S. population of SqVYV has undergone a recent genetic bottleneck and was introduced from elsewhere. PMID:22142477

  8. Are leaf physiological traits related to leaf water isotopic enrichment in restinga woody species?

    PubMed

    Rosado, Bruno H P; De Mattos, Eduardo A; Sternberg, Leonel Da S L

    2013-09-01

    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

  9. Leaf wax n-alkane ?D values of field-grown barley reflect leaf water ?D values at the time of leaf formation

    NASA Astrophysics Data System (ADS)

    Sachse, Dirk; Gleixner, Gerd; Wilkes, Heinz; Kahmen, Ansgar

    2010-12-01

    Leaf wax n-alkanes from barley ( Hordeum vulgare) from a field in Switzerland exhibited changes in ?D values on the order of 20‰ over a growing season, while source water (soil water) and leaf water varied by 40‰. Additionally the seasonal variability in ?D values of leaf wax n-alkanes of different barley leaves can only be found across different leaf generations (i.e. leaves that were produced at different times during the growing season) while n-alkane ?D values did not vary significantly within a leaf generation. Interestingly, ?D values of n-alkanes correlated best with the ?D values of leaf water at midday of the sampling day but showed no significant correlation with soil water (e.g. precipitation) ?D values. These results provide empirical evidence that leaf wax ?D values record leaf water enrichment, and therefore integrate the isotopic effects of precipitation and evapotranspiration. Our results show that leaf wax n-alkane ?D values from grasses are 'locked in' early during leaf development and hence record the environmental drivers of leaf water enrichment, such as vapor pressure deficit (VPD). Our data have important implications for the interpretation of paleorecords of leaf wax ?D. We suggest that leaf wax n-alkane ?D values from sedimentary records could be used to estimate changes in the degree of leaf water enrichment and hence VPD.

  10. What Is a Leaf? An Online Tutorial and Tests

    ERIC Educational Resources Information Center

    Burrows, Geoffrey

    2008-01-01

    A leaf is a fundamental unit in botany and understanding what constitutes a leaf is fundamental to many plant science activities. My observations and subsequent testing indicated that many students could not confidently and consistently recognise a leaf from a leaflet, or recognise basic leaf arrangements and the various types of compound or…

  11. Purdue extensionGray Leaf Spot Purdue extension

    E-print Network

    1 Purdue extensionGray Leaf Spot BP-56-W Purdue extension d i s e a s e s o f c o r n Gray Leaf. Severeleaftissueblightingcanoccurandresultinyieldloss. Gray leaf spot on corn, caused by the fungus Cercospora zeae-maydis, is a peren- nial susceptibility and weather strongly influence disease develop- ment, which is why gray leaf spot can be locally

  12. 7 CFR 28.511 - Leaf Grade No. 1.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Leaf Grade No. 1. 28.511 Section 28.511...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.511 Leaf Grade No. 1. Leaf grade No. 1 shall...

  13. 7 CFR 28.516 - Leaf Grade No. 6.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Leaf Grade No. 6. 28.516 Section 28.516...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.516 Leaf Grade No. 6. Leaf grade No. 6 shall...

  14. INTRODUCTION The maize leaf is a photosynthetic organ comprising three

    E-print Network

    Pawlowski, Wojtek

    INTRODUCTION The maize leaf is a photosynthetic organ comprising three basic parts; the proximal. The leaf is one component of a phytomer, the basic, repeating structural unit of the maize plant (Galinat prophyll), the node, and the leaf. In maize, the tubular base of the leaf extends into the node

  15. 7 CFR 28.512 - Leaf Grade No. 2.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Leaf Grade No. 2. 28.512 Section 28.512...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.512 Leaf Grade No. 2. Leaf grade No. 2 shall...

  16. 7 CFR 28.513 - Leaf Grade No. 3.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Leaf Grade No. 3. 28.513 Section 28.513...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.513 Leaf Grade No. 3. Leaf grade No. 3 shall...

  17. 7 CFR 28.514 - Leaf Grade No. 4.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Leaf Grade No. 4. 28.514 Section 28.514...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.514 Leaf Grade No. 4. Leaf grade No. 4 shall...

  18. 7 CFR 28.512 - Leaf Grade No. 2.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Leaf Grade No. 2. 28.512 Section 28.512...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.512 Leaf Grade No. 2. Leaf grade No. 2 shall...

  19. 7 CFR 28.514 - Leaf Grade No. 4.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Leaf Grade No. 4. 28.514 Section 28.514...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.514 Leaf Grade No. 4. Leaf grade No. 4 shall...

  20. 7 CFR 28.515 - Leaf Grade No. 5.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Leaf Grade No. 5. 28.515 Section 28.515...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.515 Leaf Grade No. 5. Leaf grade No. 5 shall...

  1. 7 CFR 28.514 - Leaf Grade No. 4.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Leaf Grade No. 4. 28.514 Section 28.514...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.514 Leaf Grade No. 4. Leaf grade No. 4 shall...

  2. Leaf litter ant diversity in Guyana JOHN S. LAPOLLA1,

    E-print Network

    Schultz, Ted

    -1 Leaf litter ant diversity in Guyana JOHN S. LAPOLLA1, *, TED SUMAN1 , JEFFREY SOSA-CALVO1 Shield, Leaf litter ants Abstract. Leaf litter ants are an important group of organisms for informing conservation plan- ning. This study presents the beginning of a leaf litter ant dataset for Guyana. Following

  3. 7 CFR 28.515 - Leaf Grade No. 5.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Leaf Grade No. 5. 28.515 Section 28.515...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.515 Leaf Grade No. 5. Leaf grade No. 5 shall...

  4. 7 CFR 28.515 - Leaf Grade No. 5.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Leaf Grade No. 5. 28.515 Section 28.515...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.515 Leaf Grade No. 5. Leaf grade No. 5 shall...

  5. 7 CFR 28.513 - Leaf Grade No. 3.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Leaf Grade No. 3. 28.513 Section 28.513...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.513 Leaf Grade No. 3. Leaf grade No. 3 shall...

  6. Leaf Deformation Taking Into Account Fluid Flow Paulo Silva

    E-print Network

    Ouhyoung, Ming

    Leaf Deformation Taking Into Account Fluid Flow Paulo Silva The University of Tokyo Yonghao Yue--This paper proposes a method for animating leaf structural deformation considering the leaf water content the leaf, and couple the mass-spring parameters with a simulation representing the fluid flow

  7. 7 CFR 28.511 - Leaf Grade No. 1.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Leaf Grade No. 1. 28.511 Section 28.511...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.511 Leaf Grade No. 1. Leaf grade No. 1 shall...

  8. 7 CFR 28.511 - Leaf Grade No. 1.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Leaf Grade No. 1. 28.511 Section 28.511...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.511 Leaf Grade No. 1. Leaf grade No. 1 shall...

  9. 7 CFR 28.516 - Leaf Grade No. 6.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Leaf Grade No. 6. 28.516 Section 28.516...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.516 Leaf Grade No. 6. Leaf grade No. 6 shall...

  10. 7 CFR 28.516 - Leaf Grade No. 6.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Leaf Grade No. 6. 28.516 Section 28.516...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.516 Leaf Grade No. 6. Leaf grade No. 6 shall...

  11. 7 CFR 28.512 - Leaf Grade No. 2.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Leaf Grade No. 2. 28.512 Section 28.512...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.512 Leaf Grade No. 2. Leaf grade No. 2 shall...

  12. 7 CFR 28.513 - Leaf Grade No. 3.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Leaf Grade No. 3. 28.513 Section 28.513...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.513 Leaf Grade No. 3. Leaf grade No. 3 shall...

  13. Effect of Image Processing of a Leaf Photograph on the Calculated Fractal Dimension of Leaf Veins

    Microsoft Academic Search

    Yun Kong; Shaohui Wang; Chengwei Ma; Baoming Li; Yuncong Yao

    2007-01-01

    Digital photography is a promised method for estimating the fractal characteristics of leaf veins. In this study, the effects\\u000a of different threshold levels and image processing methods using Adobe Photoshop software on the fractal dimension values\\u000a were examined from a digital photo of nectarine leaf. The results showed that the nectarine leaf vein has typical fractal\\u000a characteristics and its fractal

  14. Short communication Leaf optical properties and photosynthetic leaf absorptances in several Australian seagrasses

    Microsoft Academic Search

    Michael J. Durako

    Thisstudyinvestigated within-and among-species variability intheleafoptical properties ofeightlarge-bodiedseagrasses,Posidoniaaustralis, Posidonia sinuosa, Posidonia coriacea, Posidonia angustifolia, Amphibolis antarctica, Amphibolis griffithii, Zostera tasmanica, and Zostera capricorni and the small-bodied Halophila ovalis from the east and west coasts of Australia. Leaf spectral transmittance (TL(l)), reflectance (RL(l)), and non-photosynthetic absorptance (AL(NP)) were measured in order to calculate leaf spectral absorptance (AL(l)) and photosynthetic leaf absorptance (AL(PAR)).

  15. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell...

  16. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell...

  17. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell...

  18. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell...

  19. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3527 Leaf structure. The cell...

  20. How a leaf gets its shape.

    PubMed

    Moon, Jihyun; Hake, Sarah

    2011-02-01

    Leaves are formed from a group of initial cells within the meristem. One of the earliest markers of leaf initiation is the down-regulation of KNOX genes in initial cells. Polar auxin activity, MYB and LOB domain transcription factors function to keep KNOX out of the initiating leaf. If KNOX genes are expressed in initial cells, leaves fail to form. As the leaf grows away from the meristem, its shape is determined by growth in three axes, proximal-distal, abaxial-adaxial and medial-lateral. HD-ZIPIII, KANADI and the small RNA pathway play a significant role in the latter two axes. KNOX proteins play a role in the proximal-distal axis. Although genetic networks are conserved between monocots and dicots, the outcome in leaf shape often differs. PMID:20870452

  1. A hotspot model for leaf canopies

    NASA Technical Reports Server (NTRS)

    Jupp, David L. B.; Strahler, Alan H.

    1991-01-01

    The hotspot effect, which provides important information about canopy structure, is modeled using general principles of environmental physics as driven by parameters of interest in remote sensing, such as leaf size, leaf shape, leaf area index, and leaf angle distribution. Specific examples are derived for canopies of horizontal leaves. The hotspot effect is implemented within the framework of the model developed by Suits (1972) for a canopy of leaves to illustrate what might occur in an agricultural crop. Because the hotspot effect arises from very basic geometrical principles and is scale-free, it occurs similarly in woodlands, forests, crops, rough soil surfaces, and clouds. The scaling principles advanced are also significant factors in the production of image spatial and angular variance and covariance which can be used to assess land cover structure through remote sensing.

  2. Spectroscopic Measurement of Leaf Water Status

    NASA Technical Reports Server (NTRS)

    Goetz, Alexander F. H.; Boardman, Joseph W.

    1995-01-01

    A leaf drying experiment was carried out in the laboratory in which simultaneous spectral reflectance in the 350-2450 nm region, and leaf weights, were measured at 10 second intervals over a 40 minute period. As the leaf water weight dropped from approximately 60 to 38%. a nearly-linear rise in reflectance at all wavelengths beyond 1000 nm was observed. A principal components analysis of the time series of spectra in the 2000-2500 nm wavelength region showed that over 99% of the variance in the spectra, that were individually scaled to have a sum equal to that of the mean spectrum and subsequently mean corrected, was in the first component. This result shows that it is feasible to determine leaf water content remotely with an imaging spectrometer independent of the surface irradiance effects caused by topography.

  3. Monitoring Air Quality with Leaf Yeasts.

    ERIC Educational Resources Information Center

    Richardson, D. H. S.; And Others

    1985-01-01

    Proposes that leaf yeast serve as quick, inexpensive, and effective techniques for monitoring air quality. Outlines procedures and provides suggestions for data analysis. Includes results from sample school groups who employed this technique. (ML)

  4. NbPHAN, a MYB transcriptional factor, regulates leaf development and affects drought tolerance in Nicotiana benthamiana.

    PubMed

    Huang, Changjun; Hu, Gaojie; Li, Fangfang; Li, Yunqin; Wu, Jianxiang; Zhou, Xueping

    2013-11-01

    MYB transcriptional factors, characterized by the presence of conserved DNA-binding domains (BDs) (MYB domain), are involved in diverse processes including plant growth, development, metabolic and stress responses. In this study, a new R2R3-type MYB gene, NbPHAN (Nicotiana benthamiana PHANTASTICA), was identified in N. benthamiana. The NbPHAN encodes a protein of 362 amino acids and shares high sequence identities with the AS1-RS2-PHANs (ARPs) from other plant species. The NbPHAN protein targets to and forms homodimers in the nucleus. The MYB domain and C-terminal region of NbPHAN determine its subcellular localization and homodimerization, respectively. Using virus-induced gene silencing, we showed that the NbPHAN-silenced leaves exhibited severe downward curling and abnormal growth of blades along the main veins through suppressing the expression of the NTH20 gene. In addition, we found NbPHAN plays an important role in drought tolerance. The NbPHAN-silenced plants exhibited severe wilting and increased rate of water loss than that found in the non-silenced plants when growing under the water deficit condition. Although abscisic acid accumulation was not altered in the NbPHAN-silenced plants as compared with that in the non-silenced plants, several other stress-inducible genes were clearly repressed under the water deficit condition. Our results provide strong evidence that other than controlling leaf development, the ARP genes can also regulate plant tolerance to drought stress. PMID:23387304

  5. Remote sensing of leaf water status

    NASA Technical Reports Server (NTRS)

    Ripple, William J.; Schrumpf, Barry J.

    1987-01-01

    Relative water content (RWC) measurements were made concurrently with spectral reflectance measurements from individual snapbean leaves. The relationships between spectra and RWC were described using second order polynomial equations. The middle infrared bands most sensitive to changes in leaf RWC also had the highest water absorption coefficients, as published by Curcio Petty (1951). The relationship between reflectance at 2100nm and total water potential for a single leaf was found to be linear.

  6. How cellulose-based leaf toughness and lamina density contribute to long leaf lifespan of shade tolerant species

    E-print Network

    Kitajima, Kaoru

    and methanol extraction. Leaf dry mass content (LDMC) was determined by dividing dry mass by fresh mass for #12How cellulose-based leaf toughness and lamina density contribute to long leaf For cutting test, each fresh leaf disk was trimmed and oriented so that the cutting pass was sufficiently long

  7. The effect of elevated CO2 on diel leaf growth cycle, leaf carbohydrate content and canopy growth

    E-print Network

    Barron-Gafford, Greg

    The effect of elevated CO2 on diel leaf growth cycle, leaf carbohydrate content and canopy growth the effect of elevated CO2 on the diel leaf growth cycle for the first time in a dicot plant. Growing leaves at dusk. At the beginning of the season, leaf growth did not differ between treatments. At the end

  8. Summary Leaf structure has been shown to be an important determinant of leaf photosynthetic characteristics, yet the na-

    E-print Network

    Green, Scott

    Summary Leaf structure has been shown to be an important determinant of leaf photosynthetic characteristics, yet the na- ture of this relationship remains ambiguous. It has been sug- gested that intra-leaf shading of chloroplasts may explain the negative influence of increasing leaf thickness/density on mass

  9. Ginseng leaf-stem: bioactive constituents and pharmacological functions

    Microsoft Academic Search

    Hongwei Wang; Dacheng Peng; Jingtian Xie

    2009-01-01

    Ginseng root is used more often than other parts such as leaf stem although extracts from ginseng leaf-stem also contain similar active ingredients with pharmacological functions. Ginseng's leaf-stems are more readily available at a lower cost than its root. This article reviews the pharmacological effects of ginseng leaf-stem on some diseases and adverse effects due to excessive consumption. Ginseng leaf-stem

  10. Nutrient influences on leaf photosynthesis

    SciTech Connect

    Longstreth, D.J.; Nobel, P.S.

    1980-01-01

    The net rate of CO/sub 2/ uptake for leaves of Gossypium hirsutum L. was reduced when the plants were grown at low concentrations of NO/sub 3//sup -/, PO/sub 4//sup 2 -/, or K/sup +/. The water vapor conductance was relatively constant for all nutrient levels, indicating little effect on stomatal response. Although leaves under nutrient stress tended to be lower in chlorophyll and thinner, the ratio of mesophyll surface area to leaf area did not change appreciably. Thus, the reduction in CO/sub 2/ uptake rate at low nutrient levels was due to a decrease in the CO/sub 2/ conductance expressed per unit mesophyll cell wall area (g/sub CO/sup cell//sub 2/). The use of g/sub CO//sup cell//sub 2/ and nutrient levels expressed per unit of mesophyll cell wall provides a new means of assessing nutrient effects on CO/sub 2/ uptake of leaves. 14 figures, 1 table.

  11. Root Hypoxia Reduces Leaf Growth 1

    PubMed Central

    Smit, Barbara A.; Neuman, Dawn S.; Stachowiak, Matthew L.

    1990-01-01

    This study examined the potential role of restricted phloem export, or import of substances from the roots in the leaf growth response to root hypoxia. In addition, the effects of root hypoxia on abscisic acid (ABA) and zeatin riboside (ZR) levels were measured and their effects on in vitro growth determined. Imposition of root hypoxia in the dark when transpirational water flux was minimal delayed the reduction in leaf growth until the following light period. Restriction of phloem transport by stem girdling did not eliminate the hypoxia-induced reduction in leaf growth. In vitro growth of leaf discs was inhibited in the presence of xylem sap collected from hypoxic roots, and also by millimolar ABA. Disc growth was promoted by sap from aerated roots and by 0.1 micromolar ZR. The flux of both ABA and ZR was reduced in xylem sap from hypoxic roots. Leaf ABA transiently increased twofold after 24 hours of hypoxia exposure but there were no changes in leaf cytokinin levels. Images Figure 3 Figure 4 PMID:16667366

  12. Decline of leaf hydraulic conductance with dehydration: relationship to leaf size and venation architecture.

    PubMed

    Scoffoni, Christine; Rawls, Michael; McKown, Athena; Cochard, Hervé; Sack, Lawren

    2011-06-01

    Across plant species, leaves vary enormously in their size and their venation architecture, of which one major function is to replace water lost to transpiration. The leaf hydraulic conductance (K(leaf)) represents the capacity of the transport system to deliver water, allowing stomata to remain open for photosynthesis. Previous studies showed that K(leaf) relates to vein density (vein length per area). Additionally, venation architecture determines the sensitivity of K(leaf) to damage; severing the midrib caused K(leaf) and gas exchange to decline, with lesser impacts in leaves with higher major vein density that provided more numerous water flow pathways around the damaged vein. Because xylem embolism during dehydration also reduces K(leaf), we hypothesized that higher major vein density would also reduce hydraulic vulnerability. Smaller leaves, which generally have higher major vein density, would thus have lower hydraulic vulnerability. Tests using simulations with a spatially explicit model confirmed that smaller leaves with higher major vein density were more tolerant of major vein embolism. Additionally, for 10 species ranging strongly in drought tolerance, hydraulic vulnerability, determined as the leaf water potential at 50% and 80% loss of K(leaf), was lower with greater major vein density and smaller leaf size (|r| = 0.85-0.90; P < 0.01). These relationships were independent of other aspects of physiological and morphological drought tolerance. These findings point to a new functional role of venation architecture and small leaf size in drought tolerance, potentially contributing to well-known biogeographic trends in leaf size. PMID:21511989

  13. Fabrication of biomimetic superhydrophobic surfaces inspired by lotus leaf and silver ragwort leaf

    Microsoft Academic Search

    Jinyou Lin; Yu Cai; Xianfeng Wang; Bin Ding; Jianyong Yu; Moran Wang

    2011-01-01

    Inspired by the self-cleaning lotus leaf and silver ragwort leaf, here we demonstrate the fabrication of biomimetic superhydrophobic fibrous mats via electrospinning polystyrene (PS) solution in the presence of silica nanoparticles. The resultant electrospun fiber surfaces exhibited a fascinating structure with the combination of nano-protrusions and numerous grooves due to the rapid phase separation in electrospinning. The content of silica

  14. Specific leaf area and leaf dry matter content of plants growing in sand dunes

    Microsoft Academic Search

    Yulin LI; Douglas A. JOHNSON; Yongzhong SU; Jianyuan CUI; Tonghui ZHANG

    2005-01-01

    We investigated the variations in specific leaf area (SLA) and leaf dry matter content (LDMC) of 20 species (10 annuals and 10 perennials) that have different distributional patterns in the Kerqin Sandy Land in north- ern China. The main purpose of our study was to determine if SLA and\\/or LDMC could be used as indicators of plant resource-use strategy in

  15. Coffee leaf volatiles and egg laying by the coffee leaf miner Leucoptera coffeella

    Microsoft Academic Search

    Sérgio Tinôco V. Magalhães; Raul Narciso C. Guedes; Eraldo R. Lima; Antonio J. Demuner

    2008-01-01

    Recent reports of coffee genotypes resistant to one of its key pests in the Neotropical region, the leaf miner Leucoptera coffeella (Lepidoptera: Lyonetiidae), sparked studies trying to recognize the underlying causes of resistance. An association between increased egg laying by the leaf miner and increased caffeine levels in coffee leaves was recently recognized. However, since caffeine is not volatile, its

  16. Leaf lifespan as a determinant of leaf structure and function among 23 amazonian tree species

    Microsoft Academic Search

    P. B. Reich; C. Uhl; M. B. Walters; D. S. Ellsworth

    1991-01-01

    The relationships between resource availability, plant succession, and species' life history traits are often considered key to understanding variation among species and communities. Leaf lifespan is one trait important in this regard. We observed that leaf lifespan varies 30-fold among 23 species from natural and disturbed communities within a 1-km radius in the northern Amazon basin, near San Carlos de

  17. Stomatal Closure during Leaf Dehydration, Correlation with Other Leaf Physiological Traits1

    E-print Network

    Holbrook, N. Michele

    functions of the leaf to determine which responds most similarly to stomata during desiccation. Leaf of embolisms. Stomata appear in the fossil record approximately 400 million years ago (Edwards et al., 1998 of stomatal clo- sure, the fundamental question of why stomata close remains unanswered. Given that stomata

  18. Measurement of leaf relative water content by infrared reflectance

    NASA Technical Reports Server (NTRS)

    Hunt, E. Raymond, Jr.; Rock, Barrett N.; Nobel, Park S.

    1987-01-01

    From basic considerations and Beer's law, a leaf water content index incorporating reflectances of wavelengths from 0.76 to 0.90 microns and from 1.55 to 1.75 microns was developed that relates leaf reflectance to leaf relative water content. For the leaf succulent, Agave deserti, the leaf water content index was not significantly different from the relative water content for either individual leaves or an entire plant. Also, the relative water contents of intact plants of Encelia farinosa and Hilaria rigida in the field were estimated by the leaf water content index; variations in the proportion of living to dead leaf area could cause large errors in the estimate of relative water content. Thus, the leaf water content index may be able to estimate average relative water content of canopies when TM4 and TM5 are measured at a known relative water content and fraction of dead leaf material.

  19. The Scaling Relationships between Leaf Mass and Leaf Area of Vascular Plant Species Change with Altitude

    PubMed Central

    Pan, Sha; Liu, Chao; Zhang, Weiping; Xu, Shanshan; Wang, Nan; Li, Yan; Gao, Jing; Wang, Yang; Wang, Genxuan

    2013-01-01

    The scaling relationship between leaf dry mass and leaf surface area has important implications for understanding the ability of plants to harvest sunlight and grow. Whether and how the scaling relationships vary across environmental gradients are poorly understood. We analyzed the scaling relationships between leaf mass and leaf area of 121 vascular plant species along an altitudinal gradient in a subtropical monsoon forest. The slopes increased significantly with altitude, it varied from less than 1 at low altitude to more than 1 at high altitude. This means that plants growing at high altitude allocate proportionately more biomass to support tissues in larger leaves and less in smaller leaves, whereas the reverse is true at low altitude. This pattern can be explained by different leaf strategies in response to environmental pressure and constrains. PMID:24146938

  20. In vitro response of leaf tissues from Lolium multiflorum — a comparison with leaf segment position, leaf age and in vivo mitotic activity

    Microsoft Academic Search

    O. I. Joarder; N. H. Joarder; P. J. Dale

    1986-01-01

    Immature gramineous leaves provide a convenient system for comparing the response of cells in culture with their state of differentiation. Callusing frequency is compared with leaf segment position, leaf age and in vivo mitotic activity in Lolium multiflorum. (1) In a succession of one millimeter sections from the immature leaf base, callus was formed from the first and second sections

  1. Role of chloroplastidial proteases in leaf senescence

    PubMed Central

    Goud, Prashanth B

    2011-01-01

    In this report the effect of hydrogen peroxide (H2O2) on peroxidase (POD) activity during leaf senescence was studied with and without phenylmethylsulfonyl fluoride (PMSF) pre-treatment in detached neem (Azadirachta indica A. juss) leaf chloroplasts. Increased POD activity was detected in natural and H2O2-promoted senescent leaf chloroplasts compared to untreated control mature green leaf chloroplasts. However, under H2O2 POD activity markedly increased at 1 day, and then significantly decreased until 4 days. In the presence of H2O2, PMSF, the induction of POD activity was alleviated at 1 day, whereas reduced after 4 days. In contrast, in the presence of H2O2, cycloheximide (CX), the induction of POD activity was reduced at 1 day, whereas alleviated after 4 days. The was a partial reduction in H2O2-induced POD activity with PMSF and CX, indicating the presence of pre-existing inactive PODs in chloroplasts. We also propose a new role for chloroplastidial proteases as activators of pre-existing inactive PODs during leaf senescence. PMID:22024830

  2. Persimmon leaf flavonoid promotes brain ischemic tolerance

    PubMed Central

    Miao, Mingsan; Zhang, Xuexia; Bai, Ming; Wang, Linan

    2013-01-01

    Persimmon leaf flavonoid has been shown to enhance brain ischemic tolerance in mice, but its mechanism of action remains unclear. The bilateral common carotid arteries were occluded using a micro clip to block blood flow for 10 minutes. After 10 minutes of ischemic preconditioning, 200, 100, and 50 mg/kg persimmon leaf flavonoid or 20 mg/kg ginaton was intragastrically administered per day for 5 days. At 1 hour after the final administration, ischemia/reperfusion models were estab-lished by blocking the middle cerebral artery for 2 hours. At 24 hours after model establishment, compared with cerebral ischemic rats without ischemic preconditioning or drug intervention, plasma endothelin, thrombomodulin and von Willebrand factor levels significantly decreased and intercel-lular adhesion molecule-1 expression markedly reduced in brain tissue from rats with ischemic pre-conditioning. Simultaneously, brain tissue injury reduced. Ischemic preconditioning combined with drug exposure noticeably improved the effects of the above-mentioned indices, and the effects of 200 mg/kg persimmon leaf flavonoid were similar to 20 mg/kg ginaton treatment. These results indicate that ischemic preconditioning produces tolerance to recurrent severe cerebral ischemia. However, persimmon leaf flavonoid can elevate ischemic tolerance by reducing inflammatory reactions and vascular endothelial injury. High-dose persimmon leaf flavonoid showed an identical effect to ginaton. PMID:25206573

  3. BOREAS TE-9 NSA Leaf Chlorophyll Density

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Margolis, Hank; Sy, Mikailou

    2000-01-01

    The BOREAS TE-9 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. These data were collected to help provide an explanation of potential seasonal and spatial changes of leaf pigment properties in boreal forest species at the NSA. At different dates (FFC-Winter, FFC-Thaw, IFC-1, IFC-2, and IMC-3), foliage samples were collected from the upper third of the canopy for five NSA sites (YJP, OJP, OBS, UBS, and OA) near Thompson, Manitoba. Subsamples of 100 needles for black spruce, 20 needles for jack pine, and single leaf for trembling aspen were cut into pieces and immersed in a 20-mL DMF aliquot in a Nalgene test tube. The extracted foliage materials were then oven-dried at 68 C for 48 hours and weighed. Extracted leaf dry weight was converted to a total leaf area basis to express the chlorophyll content in mg/sq cm of total leaf area. The data are provided in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  4. Synthesis of single and multi unit-wall MgB{sub 2} nanotubes by arc plasma in inert liquid via self-curling mechanism

    SciTech Connect

    Sano, Noriaki; Tamon, Hajime [Department of Chemical Engineering, Kyoto University, Kyoto 615-8510 (Japan); Kawanami, Osamu [Department of Mechanical and System Engineering, University of Hyogo, 2167 Shoha, Himeji 671-2280 (Japan)

    2011-02-01

    Magnesium diboride (MgB{sub 2}) is known as a promising superconductor due to its high transmission temperature. Similarly to single-wall carbon nanotube, unique characteristics would be seen if a nanotube structure of MgB{sub 2} having a unit-wall of Mg and B atomic bilayer is prepared. However, such MgB{sub 2} nanotubes have not ever been synthesized. In this article, formation mechanism of unit-wall MgB{sub 2} nanotube is elucidated by molecular mechanics calculation. From the viewpoint of energetic stability, the unit-wall will be curled up to form nanotube structure when MgB{sub 2} crystal is disassembled to an isolated unit-wall layer. An experiment using arc plasma in inert liquid was utilized to produce unit-wall MgB{sub 2} nanotubes. As a result, a single and multiunit-wall MgB{sub 2} nanotube was successfully synthesized. In this reaction field, the arc plasma may play a role to produce isolated MgB{sub 2} unit-wall fragment, and the cold cathode surface can contribute to preserve MgB{sub 2} nanotube structure.

  5. Stomatal Density Influences Leaf Water and Leaf Wax D/H Values in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Lee, H.; Feakins, S. J.; Sternberg, L. O.

    2014-12-01

    The hydrogen isotopic composition (?D) of plant leaf wax is a powerful tool to study the hydrology of past and present environments. The ?D value of leaf waxes is known to primarily reflect the ?D value of source water, modified by biological fractionations commonly summarized as the 'net or apparent' fractionation. It remains a challenge, however, to quantitatively relate the isotopic composition of the end product (wax) back to that of the precursor (water) because multiple isotope effects contributing to the net fractionation are not yet well understood. Transgenic variants have heretofore unexplored potential to isolate individual isotope effects. Here we report the first hydrogen isotopic measurements from transgenic Arabidopsis thaliana plants with calculations of leaf water enrichment, net and biosynthetic fractionation values from measured ?D of plant waters and leaf wax n-alkanes. We employed transgenic Arabidopsis leaves, engineered to have different stomatal density, by differential expression of the stomatal growth hormone stomagen. Comparison of variants and wild types allow us to isolate the effects of stomatal density on leaf water and the net fractionation expressed by leaf wax biomarkers. Results show that transgenic leaves with denser pores have more enriched leaf water and leaf wax ?D values than wild type and even more so than transgenic leaves with sparse stomata (difference of 10 ‰). Our findings that stomatal density controls leaf water and leaf wax ?D values adds insights into the cause of variations in net fractionations between species, as well as suggesting that geological variations in stomatal density may modulate the sedimentary leaf wax ?D record. In nature, stomatal density varies between species and environments, and all other factors being equal, this will contribute to variations in fractionations observed. Over geological history, lower stomatal densities occur at times of elevated pCO2; our findings predict reduced leaf water isotopic enrichment and larger net fractionations during these greenhouse conditions. Future work involving transgenic plants holds considerable potential to isolate additional factors which may influence the net fractionation between source water and leaf waxes adding to our fundamental understanding of this proxy.

  6. Characterization of Rhynchosia yellow mosaic Yucatan virus, a new recombinant begomovirus associated with two fabaceous weeds in Yucatan, Mexico.

    PubMed

    Hernández-Zepeda, C; Brown, J K; Moreno-Valenzuela, O A; Argüello-Astorga, G; Idris, A M; Carnevali, G; Rivera-Bustamante, R F

    2010-10-01

    Rhynchosia minima (L.) DC. (Fabaceae) plants exhibiting bright golden mosaic symptoms were previously associated with begomovirus infection in Yucatan, México [1]. To characterize the begomovirus infecting these plants, the complete bipartite genome was cloned and sequenced. Sequence comparisons indicated that the virus was distinct from all other begomoviruses known to date, including those previously identified from symptomatic R. minima, and the name Rhynchosia yellow mosaic Yucatan virus (RhYMYuV) is proposed. Pairwise comparisons indicated that RhYMYuV DNA-A [2,597 nt, (EU021216)] and DNA-B [2,542 nt, (FJ792608)] components shared the highest nt sequence identity with Cabbage leaf curl virus (CaLCuV), 87% for component A and 71% for component B. Phylogenetic analysis indicated that both components of RhYMYuV are most closely related to other New World begomoviruses, having as closest relatives immediate outliers to the major Squash leaf curl virus (SLCV) clade. Recombination analysis of the RhYMYuV genome indicated that the DNA-A component has arisen through intermolecular recombination. R. minima plants inoculated with the monomeric clones developed a bright yellow mosaic similar to symptoms observed in naturally infected plants, confirming that the clones were infectious. Nicotiana benthamiana plants biolistically inoculated with monomeric clones developed curling and chlorosis in the newly emerging leaves. RhYMYuV was also detected in symptomatic Desmodium sect. Scorpiurus Benth. (Fabaceae) that were collected near the RhYMYuV-infected plants. PMID:20574644

  7. Leaf Diffusion Resistance, Illuminance, and Transpiration 1

    PubMed Central

    Ehrler, W. L.; van Bavel, C. H. M.

    1968-01-01

    Stepwise increases in fluorescent illuminance, imposed as a single variable in a controlled environment, induced progressive stomatal opening in 8 plant species, as evidenced by a consistent decrease in leaf diffusion resistance (RL), ranging from 15 to 70 sec cm?1 in darkness to about 1 sec cm?1 at approximately 40 kilolux. The minimum RL values were the same for the upper and the lower epidermis, provided that stomatal density was adequate. Saturation illuminance was not achieved in any species; extrapolation indicates that 50 kilolux would bring about full stomatal opening (RL ? 0.1 sec cm?1). In 4 species, reasonable agreement was obtained in a controlled environment between transpiration as measured by weight loss and that calculated from determination of (a) the difference in water vapor density from leaf to air, (b) the boundary layer resistance, and (c) the leaf diffusion resistance. This result confirms the physical validity of the resistance measurement procedure. PMID:16656753

  8. A Polygalacturonase from Citrus Leaf Explants

    PubMed Central

    Riov, J.

    1974-01-01

    The relationship between polygalacturonase activity and abscission of citrus leaf explants was studied. Determination of polygalacturonase activity in citrus tissues requires concentration of the enzyme, use of a proper assay method, and inhibition of an oxidase present in the extracts which oxidizes the reaction products of the polygalacturonase. The polygalacturonase from citrus leaf explants is an exopolygalacturonase and appears to be a soluble enzyme. Polygalacturonase activity increased during abscission of citrus leaf explants and was localized in the separation layer. Ethylene accelerated the increase in polygalacturonase activity, but its effect was evident only after at least an 8-hour lag period. 2,4-Dichlorophenoxyacetic acid and cycloheximide inhibited abscission and polygalacturonase activity. It is concluded that polygalacturonase, in addition to cellulase, plays a role in abscission. Images PMID:16658697

  9. Leaf-level nitrogen use efficiency: definition and importance.

    PubMed

    Hirose, Tadaki

    2012-07-01

    Nitrogen use efficiency (NUE) has been widely used to study the relationship between nitrogen uptake and dry mass production in the plant. As a subsystem of plant nitrogen use efficiency (NUE), I have defined leaf-level NUE as the surplus production (gross production minus leaf respiration) per unit amount of nitrogen allocated to the leaf, with factorization into leaf nitrogen productivity (NP) and mean residence time of leaf nitrogen (MRT). These concepts were applied to two herbaceous stands: a perennial Solidago altissima stand and an annual Amaranthus patulus stand. S. altissima had more than three times higher leaf NUE than A. patulus due to nearly three times longer MRT of leaf N. In both species, NUE and NP were higher at the leaf level than at the plant level, because most leaf N is involved directly in the photosynthetic activity and because leaf surplus production is higher than the plant net production. MRT was longer at the plant level. The more than twice as long MRT at the plant level as at the leaf level in S. altissima was due to a large contribution of nitrogen storage belowground in the winter in this species. Thus, comparisons between a perennial and an annual system and between plant- and leaf-level NUE with their components revealed the importance of N allocation, storage, recycling, and turnover of organs for leaf photosynthetic production and plant dry mass growth. PMID:22179330

  10. Leaf-to-leaf distances and their moments in finite and infinite m-ary tree graphs

    E-print Network

    Andrew M. Goldsborough; S. Alex Rautu; Rudolf A. Römer

    2015-04-17

    We study the leaf-to-leaf distances on full and complete m-ary graphs using a recursive approach. In our formulation, leaves are ordered along a line. We find explicit analytical formulae for the sum of all paths for arbitrary leaf-to-leaf distance r as well as the average path lengths and the moments thereof. We show that the resulting explicit expressions can be recast in terms of Hurwitz-Lerch transcendants. Results for periodic trees are also given. For incomplete random binary trees, we provide first results by numerical techniques; we find a rapid drop of leaf-to-leaf distances for large r.

  11. Perfect is best: low leaf fluctuating asymmetry reduces herbivory by leaf miners.

    PubMed

    Cornelissen, Tatiana; Stiling, Peter

    2005-01-01

    Fluctuating asymmetry (FA) represents small, random variation from symmetry and can be used as an indicator of plant susceptibility to herbivory. We investigated the effects of FA of two oak species, Quercus laevis and Q. geminata, and the responses of three herbivore guilds: leaf miners, gallers, and chewers. To examine differences in FA and herbivory between individuals, 40 leaves from each tree were collected, and FA indices were calculated. To examine differences in FA and herbivory within-individuals, we sampled pairs of mined and unmined leaves for asymmetry measurements. Differences in growth of leaf miners between leaf types were determined by tracing 50 mines of each species on symmetric leaves and asymmetric leaves. Asymmetric leaves contained significantly lower concentrations of tannins and higher concentrations of nitrogen than symmetric leaves for both plant species. Both frequency of asymmetric leaves on plants and levels of asymmetry positively influenced the abundance of Brachys, Stilbosis and other leaf miners, but no significant relationship between asymmetry and herbivory was observed for Acrocercops. Brachys and Stilbosis mines were smaller on asymmetric leaves, but differences in mine survivorship between symmetric and asymmetric leaves were observed only for Stilbosis mines. This study indicated that leaf miners might use leaf FA as a cue to plant quality, although differential survivorship among leaf types was not observed for all species studied. Reasons for the different results between guilds are discussed. PMID:15378348

  12. Global variability in leaf respiration in relation to climate and leaf traits

    NASA Astrophysics Data System (ADS)

    Atkin, Owen K.

    2015-04-01

    Leaf respiration plays a vital role in regulating ecosystem functioning and the Earth's climate. Because of this, it is imperative that that Earth-system, climate and ecosystem-level models be able to accurately predict variations in rates of leaf respiration. In the field of photosynthesis research, the F/vC/B model has enabled modellers to accurately predict variations in photosynthesis through time and space. By contrast, we lack an equivalent biochemical model to predict variations in leaf respiration. Consequently, we need to rely on phenomenological approaches to model variations in respiration across the Earth's surface. Such approaches require that we develop a thorough understanding of how rates of respiration vary among species and whether global environmental gradients play a role in determining variations in leaf respiration. Dealing with these issues requires that data sets be assembled on rates of leaf respiration in biomes across the Earth's surface. In this talk, I will use a newly-assembled global database on leaf respiration and associated traits (including photosynthesis) to highlight variation in leaf respiration (and the balance between respiration and photosynthesis) across global gradients in growth temperature and aridity.

  13. Isolation and amino-acid sequence of two inhibitors of serine proteinases, members of the squash inhibitor family, from Echinocystis lobata seeds.

    PubMed

    Stachowiak, D; Polanowski, A; Bieniarz, G; Wilusz, T

    1996-01-01

    Two serine proteinase inhibitors (ELTI I and ELTI II) have been isolated from mature seeds of Echinocystis lobata by ammonium sulfate fractionation, methanol precipitation, ion exchange chromatography, affinity chromatography on immobilized anhydrotrypsin and HPLC. ELTI I and ELTI II consist of 33 and 29 amino-acid residues, respectively. The primary structures of these inhibitors are as follows: ELTI I KEEQRVCPRILMRCKRDSDCLAQCTCQQSGFCG ELTI II RVCPRILMRCKRDSDCLAQCTCQQSGFCG The inhibitors show sequence similarity with the squash inhibitor family. ELTI I differs from ELTI II only by the presence of the NH2-terminal tetrapeptide Lys-Glu-Glu-Gln. The association constants (Ka) of ELTI I and ELTI II with bovine-trypsin were determined to be 6.6 x 10(10) M-1, and 3.1 x 10(11) M-1, whereas the association constants of these inhibitors with cathepsin G were 1.2 x 10(7) M-1, and 1.1 x 10(7) M-1, respectively. PMID:8922034

  14. 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.

    PubMed

    Li, Weimin; Hilf, Mark E; Webb, Susan E; Baker, Carlye A; Adkins, Scott

    2008-08-01

    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 9836 nt SqVYV genomic RNA [excluding the poly(A) tail] has one large open reading frame encoding a single polyprotein of 3172 amino acids, typical of the genome organization for most members in the family Potyviridae. The 10 mature proteins predicted to be derived from the SqVYV polyprotein include P1a and P1b but no HC-Pro, similar to Cucumber vein yellowing virus (CVYV) but different from Sweet potato mild mottle virus (SPMMV), both recognized members of the genus Ipomovirus. Phylogenetic analysis of these proteins supports classification of SqVYV as a novel species within the genus Ipomovirus. However, the similar genome organization strategy of SqVYV and CVYV, which differs from that of SPMMV, indicates that the taxonomy of the genus Ipomovirus needs to be re-examined and a new genus created within the family Potyviridae to accommodate the observed discrepancies in ipomovirus genome organization. PMID:18455828

  15. Is leaf dry matter content a better predictor of soil fertility than specific leaf area?

    PubMed Central

    Hodgson, J. G.; Montserrat-Martí, G.; Charles, M.; Jones, G.; Wilson, P.; Shipley, B.; Sharafi, M.; Cerabolini, B. E. L.; Cornelissen, J. H. C.; Band, S. R.; Bogard, A.; Castro-Díez, P.; Guerrero-Campo, J.; Palmer, C.; Pérez-Rontomé, M. C.; Carter, G.; Hynd, A.; Romo-Díez, A.; de Torres Espuny, L.; Royo Pla, F.

    2011-01-01

    Background and Aims Specific leaf area (SLA), a key element of the ‘worldwide leaf economics spectrum’, is the preferred ‘soft’ plant trait for assessing soil fertility. SLA is a function of leaf dry matter content (LDMC) and leaf thickness (LT). The first, LDMC, defines leaf construction costs and can be used instead of SLA. However, LT identifies shade at its lowest extreme and succulence at its highest, and is not related to soil fertility. Why then is SLA more frequently used as a predictor of soil fertility than LDMC? Methods SLA, LDMC and LT were measured and leaf density (LD) estimated for almost 2000 species, and the capacity of LD to predict LDMC was examined, as was the relative contribution of LDMC and LT to the expression of SLA. Subsequently, the relationships between SLA, LDMC and LT with respect to soil fertility and shade were described. Key Results Although LD is strongly related to LDMC, and LDMC and LT each contribute equally to the expression of SLA, the exact relationships differ between ecological groupings. LDMC predicts leaf nitrogen content and soil fertility but, because LT primarily varies with light intensity, SLA increases in response to both increased shade and increased fertility. Conclusions Gradients of soil fertility are frequently also gradients of biomass accumulation with reduced irradiance lower in the canopy. Therefore, SLA, which includes both fertility and shade components, may often discriminate better between communities or treatments than LDMC. However, LDMC should always be the preferred trait for assessing gradients of soil fertility uncoupled from shade. Nevertheless, because leaves multitask, individual leaf traits do not necessarily exhibit exact functional equivalence between species. In consequence, rather than using a single stand-alone predictor, multivariate analyses using several leaf traits is recommended. PMID:21948627

  16. Mueller matrix of a dicot leaf

    NASA Astrophysics Data System (ADS)

    Vanderbilt, Vern C.; Daughtry, Craig S. T.

    2012-06-01

    A better understanding of the information contained in the spectral, polarized bidirectional reflectance and transmittance of leaves may lead to improved techniques for identifying plant species in remotely sensed imagery as well as better estimates of plant moisture and nutritional status. Here we report an investigation of the optical polarizing properties of several leaves of one species, Cannabis sativa, represented by a 3x3 Mueller matrix measured over the wavelength region 400-2,400 nm. Our results support the hypothesis that the leaf surface alters the polarization of incident light - polarizing off nadir, unpolarized incident light, for example - while the leaf volume tends to depolarized incident polarized light.

  17. Vlasov equation on a symplectic leaf

    NASA Astrophysics Data System (ADS)

    David Crawford, John; Hislop, Peter D.

    1988-12-01

    The infinite dimensional phase space of the Vlasov equation is foliated by symplectic manifolds (leaves) which are invariant under the dynamics. By adopting a Lie transform representation, exp{ W, }, for near-identity canonical transformations we obtain a local coordinate system on a leaf. The evolution equation defined by restricting the Vlasov equation to the leaf is approximately represented by the evolution of W. We derive the equation for ? tW and show that it is hamiltonian relative to the nondegenerate Kirillov-Kostant-Souriau symplectic structure.

  18. Biospeckle assessment of torn plant leaf tissue and automated computation of leaf vein density (LVD)

    NASA Astrophysics Data System (ADS)

    Zaheer Ansari, Mohammad; Nirala, Anil Kumar

    2015-05-01

    In this work we propose an alternative measure of biospeckle activity in biological leaf tissues. The activity images obtained using the proposed method i.e., weighted parameterized Fujii method show relatively higher contrast compared to the existing methods. Leave veins which were not visible using the existing methods are clearly visible using the proposed method. In addition, we have also measured leaf vein density (LVD) within a leaf tissue using biospeckle technique for the first time, to the best of our knowledge. Algorithm for computing LVD from activity images generated by the proposed method is described to facilitate ease in adopting this method.

  19. Leaf Abscisic Acid Accumulation in Response To Substrate Water Content: Linking Leaf Gas Exchange Regulation with Leaf Abscisic Acid Concentration

    Microsoft Academic Search

    William L. Bauerle; William W. Inman; Jerry B. Dudley

    2006-01-01

    ADDITIONAL INDEX WORDS. stomatal conductance, drought tolerance, genotype variation ABSTRACT. Quantitative differences in leaf abscisic acid (ABAL) among four cultivars of red maple (Acer rubrum L.) and one freeman maple (Acer ×freemanii E. Murray) cultivar were investigated. This study tested the hypothesis that ABAL concentration can be used to compare the effects of water stress on the gas exchange response

  20. Mycosphaerella species causing leaf disease in South African Eucalyptus plantations

    E-print Network

    by modern phylogenetic approaches. Species of Mycosphaerella include both saprophytes and parasitesMycosphaerella species causing leaf disease in South African Eucalyptus plantations Gavin C. HUNTER species of Mycosphaerella are associated with a destructive Eucalyptus leaf disease known

  1. Molecular Models of Leaf Extracts

    NSDL National Science Digital Library

    Our Featured Molecules this month come from the paper by Pelter et. al. on the analysis of leaf extracts by thin-layer chromatography (1). As the authors discuss, their experiment may be used in courses at various levels of the curriculum. The molecules discussed in the paper are also of wide interest both for their structural properties and their wide-ranging appearance in both natural and synthetic substances. Included in the molecule collection are all of the isomers for the molecules pictured in the text with the exception of menthyl acetate, for which only one structure is given (see below). All of these molecules have been optimized at the HF/631-G(d) level. The menthol family enantiomeric pairs of menthol, isomenthol, neomenthol and neoisomenthol provide a rich yet coherent group of molecules on which to base discussion of chirality, enantiomers and diastereomers. Treadwell and Black have described some of the differences in physical properties of four members of this family, and several other experiments using one or more menthols have been published in this Journal (2, 3). I have created a Web page in which the eight molecules are embedded in no particular order, and with no rational file names. This is being used in at least one of our organic sections to give students experience at identifying enantiomers, and diastereomers, and in applying R/S notation (4). As access to computational software becomes more common, and as efforts are being made to incorporate more relevant modeling experiments into all levels of the curriculum, the menthols again present some interesting possibilities. While students at the organic level know about enantiomers differing in their optical rotation, and about chiral molecules interacting with chiral and achiral environments, it is instructive for them to think of other ways in which enantiomers and diastereomers are the same or different. Three useful ways of checking to see whether two structures are truly enantiomers is to compute their total energies, vibrational spectra, and dipole moments. These calculations are available in most common computational packages. Figure 1 shows the results of energy calculations on optimized structures of the eight isomers. The enantiomeric pairs have, as expected, exactly the same total energy, while the various diastereomers differ in energy. The computation of the vibrational spectra is a very sensitive probe to determine whether two structures are optimized and enantiomeric or not. Structures that are almost enantiomeric, but not quite optimized, may exhibit similar energies, but the low frequency vibrations will be sensitive to any deviation from optimization. If two supposedly enantiomeric structures do not have the same computed vibrations, or if either shows a negative frequency, the structures need to be optimized more carefully. As with the vibrational frequencies, enantiomers should show identical dipole moments. Only one structure of the eight isomers in the menthyl acetate family is included in the collection, giving students the chance to build the other seven and verify their computed properties. Because of the central role that chirality plays in chemistry, and particularly in biochemistry, it seems appropriate to introduce some of these visualization and modeling exercises early in the curriculum, and in courses designed for students majoring in other areas. Students in various courses could pursue other aspects of these same molecules including odor and cooling properties, and green chemistry approaches to synthesizing menthols.

  2. Calculations of the transpiration rate and temperature of a leaf

    Microsoft Academic Search

    E. T. Linacre

    1964-01-01

    Sample calculations of the water-loss rate and the temperature of a leaf have been made in terms of three climatic factors (i. e. net radiation intensity, ambient temperature and ambient vapour pressure) and two diffusion resistances, respectively within and outside the leaf tissue. The results indicate the variability of the ratio of the respective water losses from a leaf and

  3. Pecan leaf analysis: I. Varietal, fertilizer, and seasonal effects

    Microsoft Academic Search

    R. E. Worley

    1977-01-01

    Differences in elemental content of pecan [Carya illinoensis (Wang.) K. Koch] leaves among cultivars were found for N, P, K, Ca, Mg, Mn and Zn. Of the 7 elements studied, only leaf K indicated a date by cultivar interaction. Differences in leaf K among cultivars became greater as the season progressed. Increasing rate of application of N?P?K fertilizer increased leaf

  4. Leaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought

    E-print Network

    Sack, Lawren

    simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll through the hydraulic system. The leaf hydraulic system has two components, which act essentiallyLeaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought Tolerance1[C

  5. Mapping vineyard leaf area with multispectral satellite imagery

    Microsoft Academic Search

    L. F. Johnson; D. E. Roczen; S. K. Youkhana; R. R. Nemani; D. F. Bosch

    2003-01-01

    Vineyard leaf area is a key determinant of grape characteristics and wine quality. As is frequently the case in agriculture, available ground-based leaf area measurements employed by growers are not well suited to larger area mapping. In this study, IKONOS high spatial resolution, multispectral satellite imagery was used to map leaf area throughout two commercial wine grape vineyards (approximately 800

  6. Fossil evidence for Cretaceous escalation in angiosperm leaf vein evolution

    E-print Network

    Bermingham, Eldredge

    Fossil evidence for Cretaceous escalation in angiosperm leaf vein evolution Taylor S. Feilda,1 plants that dominate modern vegetation possess leaf gas exchange potentials that far exceed those of all. Using vein density (DV) measurements of fossil angiosperm leaves, we show that the leaf hydraulic

  7. 7 CFR 29.3153 - Leaf (B Group).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...percent injury tolerance. B3GF Good Green-tan Leaf. Fleshy to medium body...percent injury tolerance. B4GF Fair Green-tan Leaf. Fleshy to medium body...percent injury tolerance. B5GF Low Green-tan Leaf. Fleshy to medium...

  8. 7 CFR 29.3153 - Leaf (B Group).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...percent injury tolerance. B3GF Good Green-tan Leaf. Fleshy to medium body...percent injury tolerance. B4GF Fair Green-tan Leaf. Fleshy to medium body...percent injury tolerance. B5GF Low Green-tan Leaf. Fleshy to medium...

  9. TEMPORAL ANALYSIS OF LEAF GROWTH UNDER CLIMATE CHANGE SCENARIOS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many of the cellular and molecular mechanisms that control leaf growth and expansion have yet to be examined, even though this information would be valuable for predicting leaf area throughout growth and could potentially be used to maximize leaf area index, which could increase canopy productivity ...

  10. Interactive computer software development for leaf area measurement

    Microsoft Academic Search

    C. Igathinathane; V. S. S. Prakash; U. Padma; G. Ravi Babu; A. R. Womac

    2006-01-01

    A novel idea of utilizing only a computer to determine leaf area and perimeter was developed. The procedure is essentially computer software developed in Visual Basic that uses the computer monitor as the working surface to trace leaf outline and determines leaf area, perimeter, length, and width. Testing the software for effects of orientation, shape, and size of objects was

  11. Mandatory Leaf Node Prediction in Hierarchical Multilabel Classification

    E-print Network

    Kwok, James Tin-Yau

    Mandatory Leaf Node Prediction in Hierarchical Multilabel Classification Wei Bi James T. Kwok Department of Computer Science and Engineering Hong Kong University of Science and Technology Clear Water Bay be required to always end at leaf nodes. This is called mandatory leaf node prediction (MLNP) and is par

  12. Research Papers Leaf Processing by Wild Chimpanzees: Physically Defended Leaves

    E-print Network

    Research Papers Leaf Processing by Wild Chimpanzees: Physically Defended Leaves Reveal Complex Andrews, Fife, Scotland Abstract The manual processing of eight species of leaf was investigated in the M-group chimpanzees of Mahale Mountains National Park, Tanzania. Leaf species varied in the extent to which physical

  13. The auxin influx carrier is essential for correct leaf positioning

    E-print Network

    Kuhlemeier, Cris

    The auxin influx carrier is essential for correct leaf positioning Pia A. Stieger, Didier Reinhardt inhibitor N-1-naphthylphtha- lamic acid (NPA) causes a complete cessation of leaf initiation, a defect and outgrowth of leaf primordia at the shoot apical meristem of tomato. By using a combination of transport

  14. ORIGINAL PAPER Factors controlling plasticity of leaf morphology

    E-print Network

    Boyer, Edmond

    ORIGINAL PAPER Factors controlling plasticity of leaf morphology in Robinia pseudoacacia L. II: the impact of water stress on leaf morphology of seedlings grown in a controlled environment chamber Yanxiang designed an experiment to analyze the effect of long-term water stress on leaf growth of Robinia seedlings

  15. 7 CFR 51.1220 - Leaf or limb rub injury.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Agriculture 2 2013-01-01 2013-01-01 false Leaf or limb rub injury. 51.1220 Section 51.1220...for Grades of Peaches Definitions § 51.1220 Leaf or limb rub injury. “Leaf or limb rub injury” means that the scarring...

  16. Oak Leaf Blister Theresa Badurek, Urban Horticulture Extension Agent

    E-print Network

    Jawitz, James W.

    Oak Leaf Blister Theresa Badurek, Urban Horticulture Extension Agent It's that time of year again spring! Wait a minute oak leaves blistering? Yes, this is a common sight in the spring. Oak leaf blister (Taphrina caerulescens) is a common fungal leaf disease on oaks in Florida. It can affect any

  17. Manual of Leaf Architecture Morphological description and categorization

    E-print Network

    Wilf, Peter

    - 1 - Manual of Leaf Architecture Morphological description and categorization of dicotyledonous reserved. Published and distributed by: Leaf Architecture Working Group c/o Scott Wing Department-9677554-0-9 Please cite as: Manual of Leaf Architecture - morphological description and categorization

  18. 9 CFR 319.702 - Lard, leaf lard.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Lard, leaf lard. 319.702 Section 319.702...Oils, Shortenings § 319.702 Lard, leaf lard. (a) Lard is the fat rendered...brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

  19. Better Algorithms and Bounds for Directed Maximum Leaf Problems

    E-print Network

    Krivelevich, Michael

    Better Algorithms and Bounds for Directed Maximum Leaf Problems Noga Alon 1 , Fedor V. Fomin 2 of Mathematical Sciences Chennai, 600 017, India saket@imsc.res.in Abstract. The Directed Maximum Leaf Out Maximum Leaf Out­Branching problem is to find an out­branching in a given digraph with the maximum number

  20. 7 CFR 51.1220 - Leaf or limb rub injury.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Agriculture 2 2014-01-01 2014-01-01 false Leaf or limb rub injury. 51.1220 Section 51.1220...for Grades of Peaches Definitions § 51.1220 Leaf or limb rub injury. “Leaf or limb rub injury” means that the scarring...

  1. Logspace and Logtime Leaf Languages \\Lambda Birgit Jenner y

    E-print Network

    McKenzie, Pierre

    Logspace and Logtime Leaf Languages \\Lambda Birgit Jenner y Universit¨at T¨ubingen Pierre Mc with input x gives rise to a leaf string formed by concatenating the outcomes of all the com­ putations in the tree in lexicographical order. We may characterize prob­ lems by considering, for a particular ``leaf

  2. 7 CFR 51.1220 - Leaf or limb rub injury.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Agriculture 2 2012-01-01 2012-01-01 false Leaf or limb rub injury. 51.1220 Section 51.1220...for Grades of Peaches Definitions § 51.1220 Leaf or limb rub injury. “Leaf or limb rub injury” means that the scarring...

  3. 9 CFR 319.702 - Lard, leaf lard.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Lard, leaf lard. 319.702 Section 319.702...Oils, Shortenings § 319.702 Lard, leaf lard. (a) Lard is the fat rendered...brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

  4. Computer-aided plant species identification (CAPSI) based on leaf

    E-print Network

    Hefei Institute of Intelligent Machines

    Computer-aided plant species identification (CAPSI) based on leaf shape matching technique Ji identification (CAPSI) approach is proposed, which is based on plant leaf images using a shape matching technique. Firstly, a DouglasÁ Peucker approximation algorithm is adopted to the original leaf shapes and a new shape

  5. 9 CFR 319.702 - Lard, leaf lard.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Lard, leaf lard. 319.702 Section 319.702...Oils, Shortenings § 319.702 Lard, leaf lard. (a) Lard is the fat rendered...brains, or settlings and skimmings. “Leaf Lard” is lard prepared from fresh...

  6. Odd Leaf Out Improving visual recognition with games

    E-print Network

    Golbeck, Jennifer

    Odd Leaf Out Improving visual recognition with games Derek Hansen, Darcy Lewis, Dana Rotman, we introduce a new game, Odd Leaf Out, which provides players with an enjoyable and educational game that serves the purpose of identifying misclassification errors in a large database of labeled leaf images

  7. 7 CFR 28.517 - Leaf Grade No. 7.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 2012-01-01 false Leaf Grade No. 7. 28.517 Section 28.517...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.517 Leaf Grade No. 7. American Pima cotton...

  8. 7 CFR 28.517 - Leaf Grade No. 7.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 2013-01-01 false Leaf Grade No. 7. 28.517 Section 28.517...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.517 Leaf Grade No. 7. American Pima cotton...

  9. 7 CFR 28.517 - Leaf Grade No. 7.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 2014-01-01 false Leaf Grade No. 7. 28.517 Section 28.517...Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.517 Leaf Grade No. 7. American Pima cotton...

  10. Leaf removal in cool seasons enhances ‘Pinot noir’ anthocyanins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Pinot noir’ grapes were harvested from a control (no leaf removal) and three complete leaf removed cluster zone treatments, which were initiated at three separate pre-véraison growth stages (bloom, grain-pea size, and bunch closure). Control and leaf–removed treatments were monitored and maintained...

  11. Mechanism for increased leaf growth in elevated CO

    Microsoft Academic Search

    Sanathanie Ranasinghe; Gail Taylor

    2010-01-01

    The effect of exposure to elevated CO2 on the pro- cesses of leaf cell production and leaf cell expansion was studied using primary leaves of Phaseolus vulgahs L. Cell division and expansion were separated tempor- ally by exposing seedlings to dim red light for 10 d (when leaf cell division was completed) followed by exposure to bright white light for

  12. Yield and leaf blade area comparisons of extra leafy to normal leafed maize (Zea mays L.)

    E-print Network

    Rushing, Ronald Wayne

    1996-01-01

    above it. The collars were removed from the leaves of two representative plants of the fourteen hybrids in each replication, and relative leaf blade areas were calculated using a Delta T Area Meter and Conveyor Belt Unit. Regression analysis showed...

  13. Aftereffects of low and high temperature pretreatment on leaf resistance, transpiration, and leaf temperature in xanthium.

    PubMed

    Drake, B G; Salisbury, F B

    1972-11-01

    Leaf resistance for water vapor (total diffusion resistance minus boundary layer resistance), transpiration, and leaf temperature were measured in attached leaves of greenhouse-grown Xanthium strumarium L. plants that had been pretreated for 72 hours with high (40 C day, 35 C night), or low (10 C day, 5 C night) air temperatures. Measurements were made in a wind tunnel at light intensity of 1.15 cal cm(-2) min(-1), air temperatures between 5 and 45 C, and wind speed of 65 cm sec(-1). Leaf resistances in low temperature pretreated plants were higher (8 to 27 sec cm(-1)) than in controls or high temperature pretreated plants (0.5 to 3 sec cm(-1)) at leaf temperatures between 5 and 25 C. Thus, the pretreatment influenced stomatal aperture. PMID:16658219

  14. Toxicity evaluation of diazinon contaminated leaf litter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diazinon is an organophosphate pesticide with widespread use on a variety of agricultural crops. Because of its use, diazinon is a potential contributor to non-point source contamination of aquatic environments. A prominent feature within these aquatic environments includes leaf litter, especially...

  15. Leaf Stomata as Bioindicators: Stimulating Student Research

    ERIC Educational Resources Information Center

    Case, Steven B.

    2006-01-01

    Stomata are the pores on leaves through which carbon dioxide, oxygen, and water vapor are exchanged with the atmosphere. Researchers have found that leaf stomatal densities change in response to several environmental variables, including humidity, light intensity, and atmospheric levels of carbon dioxide, a greenhouse gas (Van Der Burgh, Dilcher,…

  16. Deferral of Leaf Senescence with Calcium 1

    PubMed Central

    Poovaiah, B. W.; Leopold, A. C.

    1973-01-01

    In view of the possibility that senescence may be a consequence of the deterioration of membrane compartments in the cells of leaves, calcium was studied as a possible agent which might defer senescence. The senescence of corn leaf discs was deferred by added calcium, and the effect was additive to the cytokinin deferral of senescence. Likewise, the senescence of Rumex leaf discs was deferred by added calcium, and the effect was additive to the gibberellin deferral of senescence. Detailed experiments with corn leaf discs established that the increase in apparent free space associated with senescence was completely prevented by calcium. An increase in hydraulic permeability during senescence was likewise demonstrated, and this increase was deferred by calcium; calcium plus benzyladenine was even more effective. Each of the measured functions of leaf senescence (chlorophyll content, protein decrease, apparent free space increase, and hydraulic permeability increase) was suppressed by calcium, and the interpretation is offered that the effects are a consequence of the calcium function in maintaining cellular membranes. PMID:16658538

  17. Chlorophyll fluorescence emission spectrum inside a leaf

    Microsoft Academic Search

    Roberto Pedrós; Ismael Moya; Yves Goulas; Stéphane Jacquemoud

    2008-01-01

    Chlorophyll a fluorescence can be used as an early stress indicator. Fluorescence is also connected to photosynthesis so it can be proposed for global monitoring of vegetation status from a satellite platform. Nevertheless, the correct interpretation of fluorescence requires accurate physical models. The spectral shape of the leaf fluorescence free of any re-absorption effect plays a key role in the

  18. Variable depth recursion algorithm for leaf sequencing

    SciTech Connect

    Siochi, R. Alfredo C. [Department of Radiation Oncology, University of Iowa, 200 Hawkins Street, Iowa City, Iowa 52240 (United States)

    2007-02-15

    The processes of extraction and sweep are basic segmentation steps that are used in leaf sequencing algorithms. A modified version of a commercial leaf sequencer changed the way that the extracts are selected and expanded the search space, but the modification maintained the basic search paradigm of evaluating multiple solutions, each one consisting of up to 12 extracts and a sweep sequence. While it generated the best solutions compared to other published algorithms, it used more computation time. A new, faster algorithm selects one extract at a time but calls itself as an evaluation function a user-specified number of times, after which it uses the bidirectional sweeping window algorithm as the final evaluation function. To achieve a performance comparable to that of the modified commercial leaf sequencer, 2-3 calls were needed, and in all test cases, there were only slight improvements beyond two calls. For the 13 clinical test maps, computation speeds improved by a factor between 12 and 43, depending on the constraints, namely the ability to interdigitate and the avoidance of the tongue-and-groove under dose. The new algorithm was compared to the original and modified versions of the commercial leaf sequencer. It was also compared to other published algorithms for 1400, random, 15x15, test maps with 3-16 intensity levels. In every single case the new algorithm provided the best solution.

  19. Mechanisms for leaf control of gas exchange

    SciTech Connect

    Mansfield, T.A.; Davies, W.J.

    1985-03-01

    Several mechanisms enable leaf stomata to optimize water loss with respect to carbon gain. Stomatal responses to environmental variation constitute a plant's first and second lines of defense against damaging water deficits. Changes in the concentrations of endogenous growth regulations and their influence on stomata may well be important to both defense strategies.

  20. Diel leaf growth of soybean: a novel method to analyze two-dimensional leaf expansion in high temporal resolution based on a marker tracking approach (Martrack Leaf)

    PubMed Central

    2013-01-01

    Background We present a novel method for quantitative analysis of dicot leaf expansion at high temporal resolution. Image sequences of growing leaves were assessed using a marker tracking algorithm. An important feature of the method is the attachment of dark beads that serve as artificial landmarks to the leaf margin. The beads are mechanically constricted to the focal plane of a camera. Leaf expansion is approximated by the increase in area of the polygon defined by the centers of mass of the beads surrounding the leaf. Fluctuating illumination conditions often pose serious problems for tracking natural structures of a leaf; this problem is circumvented here by the use of the beads. Results The new method has been used to assess leaf growth in environmental situations with different illumination conditions that are typical in agricultural and biological experiments: Constant illumination via fluorescent light tubes in a climate chamber, a mix of natural and artificial illumination in a greenhouse and natural illumination of the situation on typical summer days in the field. Typical features of diel (24h) soybean leaf growth patterns were revealed in all three conditions, thereby demonstrating the general applicability of the method. Algorithms are provided to the entire community interested in using such approaches. Conclusions The implementation Martrack Leaf presented here is a robust method to investigate diel leaf growth rhythms both under natural and artificial illumination conditions. It will be beneficial for the further elucidation of genotype x environment x management interactions affecting leaf growth processes. PMID:23883317

  1. An improved technique for separation, bleaching and preparation of slides from fossil leaf compressions

    Microsoft Academic Search

    Grzegorz Worobiec

    2003-01-01

    Leaf slides prepared from separated Tertiary leaf compressions are valuable tools for taxonomic investigations of fossil leaf assemblages. Slides such as these help considerably in morphological investigations of fossil leaves allowing examination of their minute morphological structures. Procedures for preparing leaf slides from leaf compressions include three stages: separation (isolation) of leaf compressions with use of hydrogen peroxide, and then

  2. ANALYSIS OF HEAT BALANCE OF LEAF WITH REFERENCE TO STOMATAL RESPONSES TO ENVIRONMENTALFACTORS

    Microsoft Academic Search

    Masaharu KITANO; Hiromi EGUCHI; Tsuyoshi MATSUI

    KITANO, M., EGUCHI H. and MATSUI T. Analysis of heat balance of leaf with reference to stomatal responses to environmental factors. BIOTRONICS 12, 19-27, 1983. The heat balance of the intact cucumber leaf was examined by measuring leaf temperature and environmental factors, and transpiration rate and leaf conductance were calculated in course of time. When the leaf was radiated, leaf

  3. Effects of environmental parameters, leaf physiological properties and leaf water relations on leaf water delta18O enrichment in different Eucalyptus species.

    PubMed

    Kahmen, Ansgar; Simonin, Kevin; Tu, Kevin P; Merchant, Andrew; Callister, Andrew; Siegwolf, Rolf; Dawson, Todd E; Arndt, Stefan K

    2008-06-01

    Stable oxygen isotope ratios (delta18O) have become a valuable tool in the plant and ecosystem sciences. The interpretation of delta18O values in plant material is, however, still complicated owing to the complex interactions among factors that influence leaf water enrichment. This study investigated the interplay among environmental parameters, leaf physiological properties and leaf water relations as drivers of the isotopic enrichment of leaf water across 17 Eucalyptus species growing in a common garden. We observed large differences in maximum daily leaf water delta18O across the 17 species. By fitting different leaf water models to these empirical data, we determined that differences in leaf water delta18O across species are largely explained by variation in the Péclet effect across species. Our analyses also revealed that species-specific differences in transpiration do not explain the observed differences in delta18O while the unconstrained fitting parameter 'effective path length' (L) was highly correlated with delta18O. None of the leaf morphological or leaf water related parameters we quantified in this study correlated with the L values we determined even though L was typically interpreted as a leaf morphological/anatomical property. A sensitivity analysis supported the importance of L for explaining the variability in leaf water delta18O across different species. Our investigation highlighted the importance of future studies to quantify the leaf properties that influence L. Obtaining such information will significantly improve our understanding of what ultimately determines the delta18O values of leaf water across different plant species. PMID:18208514

  4. [A inversion model for remote sensing of leaf water content based on the leaf optical property].

    PubMed

    Fang, Mei-hong; Ju, Wei-min

    2015-01-01

    Leaf water content is a fundamental physiological characteristic parameter of crops, and plays an important role in the study of the ecological environment. The aim of the work reported in this paper was to focus upon the retrieval of leaf water content from leaf-scale reflectance spectra by developing a physical inversion model based on the radiative transfer theory and wavelet analysis techniques. A continuous wavelet transform was performed on each of leaf component specific absorption coefficients to pick wavelet coefficients that were identified as highly sensitive to leaf water content and insensitive to other components. In the present study, for identifying the most appropriate wavelet, the six frequently used wavelet functions available within MATLAB were tested. Two biorl. 5 wavelet coefficients observed at the scale of 200 nm are provided with good performance, their wave-length positions are located at 1 405 and 1 488 nm, respectively. Two factors (? and ?) of the predictive theoretical models based on the biorl. 5 wavelet coefficients of the leaf-scale reflectance spectra were determined by leaf structure parameter N. We built a database composed of thousands of simulated leaf reflectance spectra with the PROSPECT model. The entire dataset was split into two parts, with 60% the calibration subset assigned to calibrating two factors (? and ?) of the predictive theoretical model. The remaining 40% the validation subset combined with the LOPEX93 experimental dataset used for validating the models. The results showed that the accuracy of the models compare to the statistical regression models derived from the traditional vegetation indices has improved with the highest predictive coefficient of determination (R2) of 0. 987, and the model becomes more robust. This study presented that wavelet analysis has the potential to capture much more of the information contained with reflectance spectra than previous analytical approaches which have tended to focus on using a small number of optimal wavebands while discarding the majority of the spectrum. PMID:25993842

  5. ROLLED LEAF 9 , encoding a GARP protein, regulates the leaf abaxial cell fate in rice

    Microsoft Academic Search

    Song Yan; Chang-Jie Yan; Xiu-Hong Zeng; Ya-Chun Yang; Yu-Wei Fang; Chun-Yan Tian; Ya-Wei Sun; Zhu-Kuan Cheng; Ming-Hong Gu

    2008-01-01

    Leaves, the collective organ produced by the shoot apical meristem (SAM), are polarized along their adaxial–abaxial axis.\\u000a In this study, we characterized two rice (Oryza sativa) allelic rolled-leaf mutants, rolled leaf 9-1 (rl9-1) and rl9-2, which display very similar phenotypes with completely adaxialized leaves and malformed spikelets. We cloned the RL9 gene by way of a map-based cloning strategy. Molecular

  6. Molecular cytogenetic discrimination and reaction to wheat streak mosaic virus and the wheat curl mite in Zhong series of wheat--Thinopyrum intermedium partial amphiploids.

    PubMed

    Chen, Qin; Conner, R L; Li, H J; Sun, S C; Ahmad, F; Laroche, A; Graf, R J

    2003-02-01

    Thinopyrum intermedium (2n = 6x = 42, JJJsJsSS) is potentially a useful source of resistance to wheat streak mosaic virus (WSMV) and its vector, the wheat curl mite (WCM). Five partial amphiploids, namely Zhong 1, Zhong 2, Zhong 3, Zhong 4, and Zhong 5, derived from Triticum aestivum x Thinopyrum intermedium crosses produced in China, were screened for WSMV and WCM resistance. Zhong 1 and Zhong 2 had high levels of resistance to WSMV and WCM. The other three partial amphiploids, Zhong 3, 4, and 5, were resistant to WSMV, but were susceptible to WCM. Genomic in situ hybridization (GISH) using a genomic DNA probe from Pseudoroegneria strigosa (SS, 2n = 14) demonstrated that two partial amphiploids, Zhong 1 and Zhong 2, have almost the identical 10 Th. intermedium chromosomes, including four Js, four J, and two S genome chromosomes. Both of them carry two pairs of J and a pair of Js genome chromosomes and two different translocations that were not observed in the other three Zhong lines. The partial amphiploids Zhong 3, 4, and 5 have another type of basic genomic composition, which is similar to a reconstituted alien genome consisting of four S and four Js genome chromosomes of Th. intermedium (Zhong 5 has two Js chromosomes plus two Js-W translocations) with six translocated chromosomes between S and Js or J genomes. All three lines carry a specific S-S-Js translocated chromosome, which might confer resistance to barley yellow dwarf virus (BYDV-PAV). The present study identified a specific Js2 chromosome present in all five of the Zhong lines, confirming that a Js chromosome carries WSMV resistance. Resistance to WCM may be linked with J or Js chromosomes. The discovery of high levels of resistance to both WSMV and WCM in Zhong 1 and Zhong 2 offers a useful source of resistance to both the virus and its vector for wheat breeding programs. PMID:12669806

  7. Final report on the safety assessment of AloeAndongensis Extract, Aloe Andongensis Leaf Juice,aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice,aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract.

    PubMed

    2007-01-01

    Plant materials derived from the Aloe plant are used as cosmetic ingredients, including Aloe Andongensis Extract, Aloe Andongensis Leaf Juice, Aloe Arborescens Leaf Extract, Aloe Arborescens Leaf Juice, Aloe Arborescens Leaf Protoplasts, Aloe Barbadensis Flower Extract, Aloe Barbadensis Leaf, Aloe Barbadensis Leaf Extract, Aloe Barbadensis Leaf Juice, Aloe Barbadensis Leaf Polysaccharides, Aloe Barbadensis Leaf Water, Aloe Ferox Leaf Extract, Aloe Ferox Leaf Juice, and Aloe Ferox Leaf Juice Extract. These ingredients function primarily as skin-conditioning agents and are included in cosmetics only at low concentrations. The Aloe leaf consists of the pericyclic cells, found just below the plant's skin, and the inner central area of the leaf, i.e., the gel, which is used for cosmetic products. The pericyclic cells produce a bitter, yellow latex containing a number of anthraquinones, phototoxic compounds that are also gastrointestinal irritants responsible for cathartic effects. The gel contains polysaccharides, which can be acetylated, partially acetylated, or not acetylated. An industry established limit for anthraquinones in aloe-derived material for nonmedicinal use is 50 ppm or lower. Aloe-derived ingredients are used in a wide variety of cosmetic product types at concentrations of raw material that are 0.1% or less, although can be as high as 20%. The concentration of Aloe in the raw material also may vary from 100% to a low of 0.0005%. Oral administration of various anthraquinone components results in a rise in their blood concentrations, wide systemic distribution, accumulation in the liver and kidneys, and excretion in urine and feces; polysaccharide components are distributed systemically and metabolized into smaller molecules. aloe-derived material has fungicidal, antimicrobial, and antiviral activities, and has been effective in wound healing and infection treatment in animals. Aloe barbadensis (also known as Aloe vera)-derived ingredients were not toxic in acute oral studies using mice and rats. In parenteral studies, the LD(50) using mice was > 200 mg/kg, rats was > 50 mg/kg, and using dogs was > 50 mg/kg. In intravenous studies the LD(50) using mice was > 80 mg/kg, rats was > 15 mg/kg, and dogs was > 10 mg/kg. The 14-day no observed effect level (NOEL) for the Aloe polysaccharide, acemannan, in the diet of Sprague-Dawley rats, was 50,000 ppm or 4.1 to 4.6 g/kg day(-1). In a 3-month study using mice, Aloe vera (extracted in ethanol) given orally in drinking water at 100 mg/kg produced reproductive toxicity, inflammation, and mortality above that seen in control animals. Aloe vera extracted in methanol and given to mice at 100 mg/kg in drinking water for 3 months caused significant sperm damage compared to controls. Aloe barbadensis extracted with water and given to pregnant Charles Foster albino rats on gestational days (GDs) 0 through 9 was an abortifacient and produced skeletal abnormalities. Both negative and positive results were found in bacterial and mammalian cell genotoxicity assays using Aloe barbadensis-derived material, Aloe Ferox-derived material, and various anthraquinones derived from Aloe. Aloin (an anthraquinone) did not produce tumors when included in the feed of mice for 20 weeks, nor did aloin increase the incidence of colorectal tumors induced with 1,2-dimethylhydrazine. Aloe-emodin (an anthraquinone) given to mice in which tumor cells had been injected inhibited growth of malignant tumors. Other animal data also suggest that components of Aloe inhibit tumor growth and improve survival. Various in vitro assays also demonstrated anticarcinogenic activity of aloe-emodin. Diarrhea was the only adverse effect of note with the use of Aloe-derived ingredients to treat asthma, ischemic heart disease, diabetes, ulcers, skin disease, and cancer. Case reports include acute eczema, contact urticaria, and dermatitis in individuals who applied Aloe-derived ingredients topically. The Cosmetic Ingredient Review Expert Panel concluded that anthraquinone levels in the several Aloe Barbaden

  8. An evolutionary perspective on leaf economics: phylogenetics of leaf mass per area in vascular plants

    PubMed Central

    Flores, Olivier; Garnier, Eric; Wright, Ian J; Reich, Peter B; Pierce, Simon; Dìaz, Sandra; Pakeman, Robin J; Rusch, Graciela M; Bernard-Verdier, Maud; Testi, Baptiste; Bakker, Jan P; Bekker, Renée M; Cerabolini, Bruno E L; Ceriani, Roberta M; Cornu, Guillaume; Cruz, Pablo; Delcamp, Matthieu; Dolezal, Jiri; Eriksson, Ove; Fayolle, Adeline; Freitas, Helena; Golodets, Carly; Gourlet-Fleury, Sylvie; Hodgson, John G; Brusa, Guido; Kleyer, Michael; Kunzmann, Dieter; Lavorel, Sandra; Papanastasis, Vasilios P; Pérez-Harguindeguy, Natalia; Vendramini, Fernanda; Weiher, Evan

    2014-01-01

    In plant leaves, resource use follows a trade-off between rapid resource capture and conservative storage. This “worldwide leaf economics spectrum” consists of a suite of intercorrelated leaf traits, among which leaf mass per area, LMA, is one of the most fundamental as it indicates the cost of leaf construction and light-interception borne by plants. We conducted a broad-scale analysis of the evolutionary history of LMA across a large dataset of 5401 vascular plant species. The phylogenetic signal in LMA displayed low but significant conservatism, that is, leaf economics tended to be more similar among close relatives than expected by chance alone. Models of trait evolution indicated that LMA evolved under weak stabilizing selection. Moreover, results suggest that different optimal phenotypes evolved among large clades within which extremes tended to be selected against. Conservatism in LMA was strongly related to growth form, as were selection intensity and phenotypic evolutionary rates: woody plants showed higher conservatism in relation to stronger stabilizing selection and lower evolutionary rates compared to herbaceous taxa. The evolutionary history of LMA thus paints different evolutionary trajectories of vascular plant species across clades, revealing the coordination of leaf trait evolution with growth forms in response to varying selection regimes. PMID:25165520

  9. An evolutionary perspective on leaf economics: phylogenetics of leaf mass per area in vascular plants.

    PubMed

    Flores, Olivier; Garnier, Eric; Wright, Ian J; Reich, Peter B; Pierce, Simon; Dìaz, Sandra; Pakeman, Robin J; Rusch, Graciela M; Bernard-Verdier, Maud; Testi, Baptiste; Bakker, Jan P; Bekker, Renée M; Cerabolini, Bruno E L; Ceriani, Roberta M; Cornu, Guillaume; Cruz, Pablo; Delcamp, Matthieu; Dolezal, Jiri; Eriksson, Ove; Fayolle, Adeline; Freitas, Helena; Golodets, Carly; Gourlet-Fleury, Sylvie; Hodgson, John G; Brusa, Guido; Kleyer, Michael; Kunzmann, Dieter; Lavorel, Sandra; Papanastasis, Vasilios P; Pérez-Harguindeguy, Natalia; Vendramini, Fernanda; Weiher, Evan

    2014-07-01

    In plant leaves, resource use follows a trade-off between rapid resource capture and conservative storage. This "worldwide leaf economics spectrum" consists of a suite of intercorrelated leaf traits, among which leaf mass per area, LMA, is one of the most fundamental as it indicates the cost of leaf construction and light-interception borne by plants. We conducted a broad-scale analysis of the evolutionary history of LMA across a large dataset of 5401 vascular plant species. The phylogenetic signal in LMA displayed low but significant conservatism, that is, leaf economics tended to be more similar among close relatives than expected by chance alone. Models of trait evolution indicated that LMA evolved under weak stabilizing selection. Moreover, results suggest that different optimal phenotypes evolved among large clades within which extremes tended to be selected against. Conservatism in LMA was strongly related to growth form, as were selection intensity and phenotypic evolutionary rates: woody plants showed higher conservatism in relation to stronger stabilizing selection and lower evolutionary rates compared to herbaceous taxa. The evolutionary history of LMA thus paints different evolutionary trajectories of vascular plant species across clades, revealing the coordination of leaf trait evolution with growth forms in response to varying selection regimes. PMID:25165520

  10. Understanding seedling growth relationships through specific leaf area and leaf nitrogen concentration: generalisations across growth forms and growth irradiance

    Microsoft Academic Search

    Ian J. Wright; Mark Westoby

    2001-01-01

    Seedling relative growth rate (RGR) achieved under favourable growth conditions can be thought of as a useful bioassay of the potential ability of species to take advantage of favourable growth opportunities; that is, of a species' growth strategy. The consistency of relationships between RGR and its component attributes leaf nitrogen productivity (LNP), leaf N per area (LNCa), specific leaf area

  11. AIR HUMIDITY WITHIN BOUNDARYLAYER OF A TRANSPIRING LEAF I. RELATIONSHIP BETWEEN TRANSPIRATION AND WATER VAPOR DENSITY AT LEAF SURFACE

    Microsoft Academic Search

    M. KITANO; H. EGUCHI

    KITANO M. and EGUCHI H. Air humidity within boundary layer ofa transpiring leaf. 1. Relationship between transpiration and water vapor density at leafsurface. BIOTRONICS 16, 39-45, 1987. A simple system for on-line measurement of water vapor density within leaf boundary layer was developed, and water vapor density (WBO) at the cucumber leaf surface was analyzed in relation to transpiration rate

  12. Baby leaf lettuce germplasm enhancement: developing diverse populations with resistance to bacterial leaf spot caused by Xanthomonas campestris pv. vitians

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Baby leaf lettuce cultivars with resistance to bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vitians (Xcv) are needed to reduce crop losses. The objectives of this research were to assess the genetic diversity for BLS resistance in baby leaf lettuce cultivars and to select early gen...

  13. Joint Leaf chlorophyll and leaf area index retrieval from Landsat data using a regularized model inversion system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf area index (LAI) and leaf chlorophyll (Chl) content represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination, LAI and leaf Chl content provide critical information on vegetation density, vitality and photosynt...

  14. Leaf nitrate assimilation during leaf expansion period: comparison of temperate and boreal tree species

    NASA Astrophysics Data System (ADS)

    Koyama, L.; Tokuchi, N.; Kielland, K.

    2011-12-01

    We examined nitrate assimilation in several tree species to test the hypothesis that plant N acquisition is highest in early spring due to the N demands of leaf growth and the seasonal availability of soil N. Specifically, we advance the idea that trees acquire N most actively during the leaf expansion period, which serves to offset growth-dilution of foliar N. However, it has been observed that boreal species expand their leaves more rapidly than do temperate species, suggesting that they exhibit a different seasonal pattern of N acquisition than do temperate species. To examine these relationships we measured leaf nitrate reductase activity (NRA) as a proxy for nitrate assimilation, leaf expansion rates, and foliar N concentrations on three boreal tree species and three temperate tree species throughout their leaf expansion period. An evergreen species (Quercus glauca) and two deciduous species (Acer palmatum and Zelkova serrata) were investigated in temperate Japan, and three deciduous species Alnus crispa, Betula papyrifera and Populus tremuloides were chosen in a boreal forest in interior Alaska, US. The patterns of foliar N concentrations were very similar across all six species, but the mean leaf expansion period was shorter in the boreal species (about 25 days) than in temperate species (about 29 days). All temperate species showed clear peaks of leaf NRA in the middle of leaf expansion period, suggesting that leaves partly compensate for the N dilution during expansion via foliar nitrate assimilation, and that plant nitrate acquisition was effectively timed to coincide with soil N availability generally increased in early spring. By contrast, peak NRA in the boreal species were observed in different stage of leaf expansion, but as in the temperate species declined to very low levels after the leaves were fully expanded. Our results demonstrate that plant nitrate assimilation is concentrated during leaf expansion in spring and early summer, but declines to very low levels during the remaining part of the growing season. This high rate of acquisition in early spring may reflect the seasonal nature of soil nitrate dynamics as well as acquisition of N liberated over-winter in both biomes.

  15. How are leaves plumbed inside a branch? Differences in leaf-to-leaf hydraulic sectoriality among six temperate tree species.

    PubMed

    Orians, Colin M; Smith, Sigrid D P; Sack, Lawren

    2005-08-01

    The transport of water, sugar, and nutrients in trees is restricted to specific vascular pathways, and thus organs may be relatively isolated from one another (i.e. sectored). Strongly sectored leaf-to-leaf pathways have been shown for the transport of sugar and signal molecules within a shoot, but not previously for water transport. The hydraulic sectoriality of leaf-to-leaf pathways was determined for current year shoots of six temperate deciduous tree species (three ring-porous: Castanea dentata, Fraxinus americana, and Quercus rubra, and three diffuse-porous: Acer saccharum, Betula papyrifera, and Liriodendron tulipifera). Hydraulic sectoriality was determined using dye staining and a hydraulic method. In the dye method, leaf blades were removed and dye was forced into the most proximal petiole. For each petiole the vascular traces that were shared with the proximal petiole were counted. For other shoots, measurements were made of the leaf-area-specific hydraulic conductivity for the leaf-to-leaf pathways (k(LL)). In five out of the six species, patterns of sectoriality reflected phyllotaxy; both the sharing of vascular bundles between leaves and k(LL) were higher for orthostichous than non-orthostichous leaf pairs. For each species, leaf-to-leaf sectoriality was determined as the proportional differences between non-orthostichous versus orthostichous leaf pairs in their staining of shared vascular bundles and in their k(LL); for the six species these two indices of sectoriality were strongly correlated (R2=0.94; P <0.002). Species varied 8-fold in their k(LL)-based sectoriality, and ring-porous species were more sectored than diffuse-porous species. Differential leaf-to-leaf sectoriality has implications for species-specific co-ordination of leaf gas exchange and water relations within a branch, especially during fluctuations in irradiance and water and nutrient availability. PMID:15983007

  16. Variations in the polarized leaf reflectance of Sorghum bicolor

    NASA Technical Reports Server (NTRS)

    Grant, Lois; Daughtry, C. S. T.; Vanderbilt, V. C.

    1987-01-01

    The polarized reflectance factor, Rq, of sorghum (Sorghum bicolor, L.) leaves from field-grown plants was measured in situ in the summers of 1983 and 1984. In 1983, three leaves of two randomly selected plants were measured at 2-week intervals. The value of Rq varied, depending on leaf and day of measurement. Measured values of Rq for the adaxial leaf surface ranged from 16 to 53; for the abaxial leaf surface the values ranged from 28 to 69. In 1984, measurements consisted of repeated observations made on the same leaf at biweekly intervals. The values of Rq from the adaxial leaf surface ranged from 26 to 38. Values of Rq from the abaxial leaf surface increased throughout the season, from 16 to 45. Differences in Rq were attributed to changes in surface details of the leaf.

  17. Leaf endophyte load influences fungal garden development in leaf-cutting ants

    PubMed Central

    2012-01-01

    Background Previous work has shown that leaf-cutting ants prefer to cut leaf material with relatively low fungal endophyte content. This preference suggests that fungal endophytes exact a cost on the ants or on the development of their colonies. We hypothesized that endophytes may play a role in their host plants’ defense against leaf-cutting ants. To measure the long-term cost to the ant colony of fungal endophytes in their forage material, we conducted a 20-week laboratory experiment to measure fungal garden development for colonies that foraged on leaves with low or high endophyte content. Results Colony mass and the fungal garden dry mass did not differ significantly between the low and high endophyte feeding treatments. There was, however, a marginally significant trend toward greater mass of fungal garden per ant worker in the low relative to the high endophyte treatment. This trend was driven by differences in the fungal garden mass per worker from the earliest samples, when leaf-cutting ants had been foraging on low or high endophyte leaf material for only 2 weeks. At two weeks of foraging, the mean fungal garden mass per worker was 77% greater for colonies foraging on leaves with low relative to high endophyte loads. Conclusions Our data suggest that the cost of endophyte presence in ant forage material may be greatest to fungal colony development in its earliest stages, when there are few workers available to forage and to clean leaf material. This coincides with a period of high mortality for incipient colonies in the field. We discuss how the endophyte-leaf-cutter ant interaction may parallel constitutive defenses in plants, whereby endophytes reduce the rate of colony development when its risk of mortality is greatest. PMID:23140096

  18. BOREAS TE-5 Leaf Carbon Isotope Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Ehleriinger, Jim; Brooks, J. Renee; Flanagan, Larry

    2000-01-01

    The BOREAS TE-5 team collected measurements in the NSA and SSA on gas exchange, gas composition, and tree growth. This documentation describes leaf carbon isotope data that were collected in 1993 and 1994 at the NSA and SSA OJP sites, the SSA OBS site, and the NSA UBS site. In addition, leaf carbon isotope data were collected in 1994 only at the NSA and SSA OA sites. These data was collected to provide seasonal integrated physiological information for 10 to 15 common species at these 6 BOREAS sites. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  19. Downregulation of net phosphorus-uptake capacity is inversely related to leaf phosphorus-resorption proficiency in four species from a phosphorus-impoverished environment

    PubMed Central

    de Campos, Mariana C. R.; Pearse, Stuart J.; Oliveira, Rafael S.; Lambers, Hans

    2013-01-01

    Background and Aims Previous research has suggested a trade-off between the capacity of plants to downregulate their phosphorus (P) uptake capacity and their efficiency of P resorption from senescent leaves in species from P-impoverished environments. Methods To investigate this further, four Australian native species (Banksia attenuata, B. menziesii, Acacia truncata and A. xanthina) were grown in a greenhouse in nutrient solutions at a range of P concentrations [P]. Acacia plants received between 0 and 500 µm P; Banksia plants received between 0 and 10 µm P, to avoid major P-toxicity symptoms in these highly P-sensitive species. Key Results For both Acacia species, the net P-uptake rates measured at 10 µm P decreased steadily with increasing P supply during growth. In contrast, in B. attenuata, the net rate of P uptake from a solution with 10 µm P increased linearly with increasing P supply during growth. The P-uptake rate of B. menziesii showed no significant response to P supply in the growing medium. Leaf [P] of the four species supported this finding, with A. truncata and A. xanthina showing an increase up to a saturation value of 19 and 21 mg P g?1 leaf dry mass, respectively (at 500 µm P), whereas B. attenuata and B. menziesii both exhibited a linear increase in leaf [P], reaching 10 and 13 mg P g?1 leaf dry mass, respectively, without approaching a saturation point. The Banksia plants grown at 10 µm P showed mild symptoms of P toxicity, i.e. yellow spots on some leaves and drying and curling of the tips of the leaves. Leaf P-resorption efficiency was 69 % (B. attenuata), 73 % (B. menziesii), 34 % (A. truncata) and 36 % (A. xanthina). The P-resorption proficiency values were 0·08 mg P g?1 leaf dry mass (B. attenuata and B. menziesii), 0·32 mg P g?1 leaf dry mass (A. truncata) and 0·36 mg P g?1 leaf dry mass (A. xanthina). Combining the present results with additional information on P-remobilization efficiency and the capacity to downregulate P-uptake capacity for two other Australian woody species, we found a strong negative correlation between these traits. Conclusions It is concluded that species that are adapted to extremely P-impoverished soils, such as many south-western Australian Proteaceae species, have developed extremely high P-resorption efficiencies, but lost their capacity to downregulate their P-uptake mechanisms. The results support the hypothesis that the ability to resorb P from senescing leaves is inversely related to the capacity to downregulate net P uptake, possibly because constitutive synthesis of P transporters is a prerequisite for proficient P remobilization from senescing tissues. PMID:23293017

  20. Coriander leaf mediated biosynthesis of gold nanoparticles

    Microsoft Academic Search

    K. Badri Narayanan; N. Sakthivel

    2008-01-01

    Extracellular biological synthesis of gold nanoparticles was achieved by a simple biological procedure using coriander extract as the reducing agent. The aqueous gold ions when exposed to coriander leaf extract are reduced and resulted in the biosynthesis of gold nanoparticles in the size range from 6.75–57.91 nm. The gold nanoparticles were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray