Incorporation of resistance to angular leaf spot and bean common ...

African Journals Online (AJOL)

Luseko

2013-07-03

Jul 3, 2013 ... Angular leaf spot (ALS) caused by the fungus Pseudocercospora griseola and Bean common mosaic and necrosis virus (BCMV/BCMNV) are important diseases of common bean in Tanzania that can cause severe yield reduction when uncontrolled. This study was conducted to incorporate resistant genes ...

Incorporation of resistance to angular leaf spot and bean common ...

African Journals Online (AJOL)

Angular leaf spot (ALS) caused by the fungus Pseudocercospora griseola and Bean common mosaic and necrosis virus (BCMV/BCMNV) are important diseases of common bean in Tanzania that can cause severe yield reduction when uncontrolled. This study was conducted to incorporate resistant genes for ALS and ...

Species of Cercospora associated with grey leaf spot of maize

NARCIS (Netherlands)

Crous, P.W.; Groenewald, J.Z.; Groenewald, M.; Caldwell, P.; Braun, U.; Harrington, T.C.

2006-01-01

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the

Species of Cercospora associated with grey leaf spot of maize.

NARCIS (Netherlands)

Crous, P.W.; Groenewald, J.Z.; Groenewald, M.; Caldwell, P.; Braun, U.; Harrington, T.C.

2006-01-01

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the

Show us your spots! Researchers need samples of bacterial leaf spots on celery, cilantro, parsley, and other crops.

Science.gov (United States)

Since 2002, a severe leaf spot disease on parsley has occurred throughout central coastal California and particularly in Monterey County. Three different bacterial pathogens (Pseudomonas syringae pv. apii, P. syringae pv. coriandricola and an organism very closely related to P. viridiflava) have bee...

Stemphylium leaf spot of parsley in California caused by Stemphylium vesicarium

Science.gov (United States)

From 2009 through 2011, a previously undescribed disease occurred on commercial parsley in coastal (Ventura County) California. Symptoms of the disease consisted of circular to oval, tan to brown leaf spots and resulted in loss of crop quality and hence reduced yields. A fungus was consistently isol...

NOTE - Genetic control of resistance to gray leaf spot of maize in tropical germplasm

Directory of Open Access Journals (Sweden)

André Humberto de Brito

2012-01-01

Full Text Available The main goal of this study was to assess the nature and magnitude of gene effects for resistance to Cercospora leaf spot. A randomized block design with three replications was used. The data were obtained at the plant level by assessing the disease severity. The data were analyzed per experiment, using the average data per plot. A dominant-additive genetic model without epistasis was considered, with estimation of the components of means and variance. The genetic control of resistance to gray leaf spot is polygenic with predominance of the additive effects. Dominance was observed in a few small-effect loci and high heritability values.

Severity of banana leaf spot in an intercropping system in two cycles of banana Prata Anã

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Valdeir Dias Gonçalves

2008-01-01

Full Text Available Prata Anã is the most planted banana cultivar in northern Minas Gerais, Brazil. It is however susceptible toseveral pathogens. This study was carried out to evaluate the disease severity of banana leaf spot in the Prata Anã cv. in thefirst and second cycle under six different planting systems. The randomized block experimental design was used with sixtreatments and four replications. In an evaluation of the severity of banana leaf spot, no disease symptoms were found onThap Maeo and Caipira. The evolution curve of the disease indicated seasonal effects in the first and second cycles. Theseverity of banana leaf spot was highest soon after the regional rainy period from November to March. A comparison of themeans of the evaluations indicated a reduction in disease severity from the first to the second cycle.

Shoot Blight and Leaf Spot of Blueberry Anthracnose Caused by Colletotrichum acutatum

OpenAIRE

Shigenobu, YOSHIDA; Takao, TSUKIBOSHI; National Institute for Agro-Environmental Sciences; National Institute for Agro-Environmental Sciences

2002-01-01

Shoot blight and leaf spots were found on highbush blueberry trees in Tsukuba, Ibaraki, in 1999. The causal fungus was identified morphologically as Colletotrichum acutatum Simmonds ex Simmonds. This is the first report of blueberry anthracnose caused by C. acutatum in Japan.

Identification of Isolates that Cause a Leaf Spot Disease of Brassicas as Xanthomonas campestris pv. raphani and Pathogenic and Genetic Comparison with Related Pathovars.

Science.gov (United States)

Vicente, J G; Everett, B; Roberts, S J

2006-07-01

ABSTRACT Twenty-five Xanthomonas isolates, including some isolates received as either X. campestris pv. armoraciae or pv. raphani, caused discrete leaf spot symptoms when spray-inoculated onto at least one Brassica oleracea cultivar. Twelve of these isolates and four other Xanthomonas isolates were spray- and pin-inoculated onto 21 different plant species/cultivars including horseradish (Armoracia rusticana), radish (Raphanus sativus), and tomato (Lycopersicon esculentum). The remaining 13 leaf spot isolates were spray-inoculated onto a subset of 10 plant species/cultivars. The leaf spot isolates were very aggressive on several Brassica spp., radish, and tomato causing leaf spots and dark sunken lesions on the middle vein, petiole, and stem. Based on the differential reactions of several Brassica spp. and radish cultivars, the leaf spot isolates were divided into three races, with races 1 and 3 predominating. A differential series was established to determine the race-type of isolates and a gene-for-gene model based on the interaction of two avirulence genes in the pathogen races and two matching resistance genes in the differential hosts is proposed. Repetitive-DNA polymerase chain reaction-based fingerprinting was used to assess the genetic diversity of the leaf spot isolates and isolates of closely related Xanthomonas pathovars. Although there was variability within each race, the leaf spot isolates were clustered separately from the X. campestris pv. campestris isolates. We propose that X. campestris isolates that cause a nonvascular leaf spot disease on Brassica spp. should be identified as pv. raphani and not pv. armoraciae. Race-type strains and a neopathotype strain for X. campestris pv. raphani are proposed.

Neocordana gen. nov.,the causal organism of Cordana leaf spot on banana

NARCIS (Netherlands)

Hernández-Restrepo, Margarita; Groenewald, Johannes Z.; Crous, Pedro W.

2015-01-01

Cordana leaf spot of banana is shown to be associated with several species of a new genus described here as Neocordana gen. nov. Furthermore, Neocordana belongs to Pyriculariaceae (Magnaporthales) rather than Cordanaceae where the type species of Cordana, C. pauciseptata resides. Neocordana is

Somaclonal variation in hybrid poplars for resistance to Septoria leaf spot

Science.gov (United States)

M.E. Ostry; D. D. Skilling

1987-01-01

Tissue culture techniques have been used to obtain hybrid poplars with putative resistance to leaf spot caused by Septoria musiva from clones previously susceptible to the disease. Stem internode explants were used to obtain proliferating callus cultures. Adventitious bud formation and shoot proliferation were then induced. Elongated shoots were excised and rooted in a...

Molecular variability in the maize grey leaf spot pathogens in Brazil

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Kátia R. Brunelli

2008-01-01

Full Text Available Isolates of Cercospora species from leaves displaying symptoms of grey leaf spot were collected in maize-producing areas of south-central Brazil in 2001 and 2002. Restriction digests of the internal transcribed spacer region of rDNA detected the presence of the same two Cercospora species described on maize in the United States, namely C. zeae-maydis and the recently described species, C. zeina . Genetic variability among isolates was assessed by analysing 104 amplified fragment length polymorphism loci. Cluster analysis confirmed the genetic separation of isolates into two species with a mean similarity of 35%. Similarity levels within species were high, averaging 93% and 92% among isolates of C. zeae-maydis and C. zeina , respectively. The mean genetic similarity between C. zeae-maydis and C. zeina and two isolates of C. sorghi f. sp. maydis was 45% and 35%, respectively. Results of this study showed that populations of the grey leaf spot pathogens in Brazil are similar to those in the United States regarding species composition and that C. zeina is also present in Brazil.

Cercospora apii causing leaf spots on two Brazilian toxic weeds: solanum glaucophyllum and Xanthium strumarium

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Fabiano Branco Rocha

2007-03-01

Full Text Available Samples of two toxic weeds, Solanum glaucophyllum and Xanthium strumarium, bearing leaf spots symptoms were found. Cercospora apii was found associated to these leaf spots in both plants. These are the first reports of this fungus on these hosts in Brazil and its first report on S. glaucophyllum worldwide.Foram encontrados plantas das espécies Solanum glaucophyllum e Xanthium strumaruium apresentando sintomas de manchas foliares. Cercospora apii foi encontrado associado lesões foliares em ambas as plantas. Estes são os primeiros relatos desse fungo nestes hospedeiros no Brasil e o primeiro relato de sua ocorrência em S. glaucophyllum no mundo.

Late Neogene leaf assemblage from Bełchatów Lignite Mine (central Poland

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Worobiec Grzegorz

2014-12-01

Full Text Available Leaf macroremains collected in the Bełchatów Lignite Mine (central Poland were investigated. The fossil assemblage consists of leaves of Acer, Betula, Carpinus, Dicotylophyllum, Fagus, ?Magnolia, “Parrotia”, Pinus, Quercus, and Zelkova. Mesophytic (zonal elements dominate, with admixture of riparian (azonal leaf taxa. The floristic composition points to late Neogene (late Miocene to late Pliocene age and suggests favourable temperate climate with mild winters.

Response of sugar beet plants to ultraviolet-B (280-320 nm) radiation and Cercospora leaf spot disease

International Nuclear Information System (INIS)

Panagopoulos, I.; Bornman, J.F.; Björn, L.O.

1992-01-01

Sugar beet (Beta vulgaris L.) plants injected with Cercospora beticola Sacc. as well as non-infected plants were grown under visible light with or without ultraviolet-B (UV-B, 280-320 nm) radiation for 40 days. An interaction between UV-B radiation and Cercospora leaf spot disease was observed, resulting in a large reduction in leaf chlorophyll content, dry weight of leaf laminae, petioles and storage roots. Lipid peroxidation in leaves also increased the most under the combined treatments. This was also true for ultraweak luminescence from both adaxial and abaxial leaf surfaces. However, no correlation between lipid peroxidation and ultraweak luminescence was observed. Ultraviolet-B radiation given alone appeared to have either a stimulating effect, giving an increase in dry weight of laminac and reducing lipid peroxidation, or no effect. This lack of effect was seen in the absence of change in dry weight of storage roots and chlorophyll content relative to controls. The study demonstrated a harmful interaction between UV-B radiation and Cercospora leaf spot disease on sugar beet

QTL-seq approach identified genomic regions and diagnostic markers for rust and late leaf spot resistance in groundnut (Arachis hypogaea L.).

Science.gov (United States)

Pandey, Manish K; Khan, Aamir W; Singh, Vikas K; Vishwakarma, Manish K; Shasidhar, Yaduru; Kumar, Vinay; Garg, Vanika; Bhat, Ramesh S; Chitikineni, Annapurna; Janila, Pasupuleti; Guo, Baozhu; Varshney, Rajeev K

2017-08-01

Rust and late leaf spot (LLS) are the two major foliar fungal diseases in groundnut, and their co-occurrence leads to significant yield loss in addition to the deterioration of fodder quality. To identify candidate genomic regions controlling resistance to rust and LLS, whole-genome resequencing (WGRS)-based approach referred as 'QTL-seq' was deployed. A total of 231.67 Gb raw and 192.10 Gb of clean sequence data were generated through WGRS of resistant parent and the resistant and susceptible bulks for rust and LLS. Sequence analysis of bulks for rust and LLS with reference-guided resistant parent assembly identified 3136 single-nucleotide polymorphisms (SNPs) for rust and 66 SNPs for LLS with the read depth of ≥7 in the identified genomic region on pseudomolecule A03. Detailed analysis identified 30 nonsynonymous SNPs affecting 25 candidate genes for rust resistance, while 14 intronic and three synonymous SNPs affecting nine candidate genes for LLS resistance. Subsequently, allele-specific diagnostic markers were identified for three SNPs for rust resistance and one SNP for LLS resistance. Genotyping of one RIL population (TAG 24 × GPBD 4) with these four diagnostic markers revealed higher phenotypic variation for these two diseases. These results suggest usefulness of QTL-seq approach in precise and rapid identification of candidate genomic regions and development of diagnostic markers for breeding applications. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Plant growth and leaf-spot severity on eucalypt at different CO2 concentrations in the air

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Carlos Eduardo Oliveira da Silva

2014-03-01

Full Text Available The objective of this work was to evaluate the effects of increased air-CO2 concentration on plant growth and on leaf-spot caused by Cylindrocladium candelabrum in Eucalyptus urophylla. Seedlings were cultivated for 30 days at 451, 645, 904, and 1,147 µmol mol-1 CO2 ; then, they were inoculated with the pathogen and kept under the same conditions for seven days. Increased CO2 concentration increased plant height and shoot dry matter mass, and decreased disease incidence and severity. Stem diameter was not affected by the treatments. Increased concentrations of atmospheric CO2 favorably affect eucalypt growth and reduce leaf-spot severity.

Reaction of the BASE 120 lines to angular leaf spot in Puerto Rico

Science.gov (United States)

Common bean (Phaseolus vulgaris L.) is limited by diseases such as Angular leaf spot (ALS), caused by Phaeoisariopsis griseola (Sacc.) Ferraris sin. Pseudocercospora griseola (Sacc.) Crous & U. Braun. The virulence of Phaeoisariopis griseola isolate ALS-9029-JD2 from Juana Diaz, PR was determined by...

Bacterial brown leaf spot of citrus, a new disease caused by Burkholderia andropogonis

Science.gov (United States)

A new bacterial disease of citrus was recently identified in Florida and named as bacterial brown leaf spot (BBLS) of citrus. BBLS-infected citrus displayed flat, circular and brownish lesions with water-soaked margins surrounded by a chlorotic halo on leaves. Based on Biolog carbon source metabolic...

Calcium and potassium contents in nutrient solution on Phoma leaf spot intensity in coffee seedlings

Directory of Open Access Journals (Sweden)

Aricléia de Moraes Catarino

Full Text Available ABSTRACT Coffee is one of the main export commodities of Brazilian agribusiness. Phoma leaf spot [Phoma tarda (Stewart Boerema & Bollen] is one of the most important coffee fungal diseases in Brazil. Therefore, this study aimed to evaluate the intensity of Phoma leaf spot in coffee seedlings supplied with different rates of Ca+2 and K+. The study was conducted under controlled conditions in a growth chamber, at the Department of Phytopathology - UFLA, from February 2010 to December 2011. The assay was repeated twice under the same conditions. The nutrient solutions consisted of five concentrations of K+ (3, 4, 5, 6, 7 mmol L-1 and Ca+2 (2, 4, 6, 8 and 10 mmol L-1. The experiment was arranged in a randomized block design, with 25 treatments and three replicates, with two plants per plot. The areas under incidence progress curve (AUIPC and severity (AUSPC were calculated. At the lowest rate of Ca2+ (2 mmol L-1 and highest K+ (6 and 7 mmol L-1, approximately, the AUIPC was the smallest. For the AUSPC, the lowest rates of Ca+2 and K+ resulted in the lowest severities. Supply of Ca+2 and K+ in nutrient solution reduced AUIPC and AUSPC of Phoma leaf spot, and these nutrients can be recommended for the management of the disease.

Potential of Trichoderma species on Helminthosporium causing leaf spot on cane palm, Chrysalidocarpus lutescens.

Science.gov (United States)

Jegathambigai, V; Karunaratne, M D S D; Svinningen, A; Mikunthan, G

2008-01-01

The cane palm, Chrysalidocarpus lutescens is one among the plant material of the export industries in Sri Lanka. The export quality of C. lutescens was declined due to the repeated occurrence of a leaf spot caused by Helminthosporium. Widespread occurrence of the leaf spot affected the cane palm production and succumb it to a huge setback in the floriculture industry in Sri Lanka. Being an export industry eco-friendly means of disease control was the prime focus for a better management of such vulnerable disease. Trichoderma is a potential bio agent, which has definite role in suppressing the inoculum of Helminthosporium sp. This study aims to evaluate the efficacy of Trichoderma species to control naturally established leaf spot in cane palm under field conditions. Three isolates of T. viride and two isolates of T. harzianum were evaluated. All the Trichoderma species performed significantly in reducing the disease incidence. T. viride + T. harzianum combination (1 x 10(10) cfu/ml) was the best compared to chemical in decreasing the mean disease severity index and improving the frequency of healthy plants. The colour of the leaves regained due to the application of Trichoderma sp. The results revealed that leaf spot incidence was lowered significantly in cane palms treated with Trichoderma species followed by treatment with combination of Trichoderma sp. and fungicides. The fungicide mixture (hexaconozole 50 g/l + Isoprothiolane 400 g/l) failed to lower the disease incidence and had no effect in suppressing the inocula of Helminthosporium, although recommended. Mixing of Trichoderma species with fungicide did not exhibit any additive effect. The combination of different species of Trichoderma would target species of Helminthosporium that exist as a complex group under field conditions. The results also proved that the existence of heterogeneity in Helminthosporium that could be tackled and effectively controlled by a combination of different species of the bio

Efficacy of management tools for control of Phytophthora plurivora leaf spot of Rhododendron, 2014

Science.gov (United States)

This study was conducted as part of the IR-4 Ornamental Horticulture program to evaluate fungicides and biopesticides for management of leaf spot of Rhododendron caused by Phytophthora plurivora. The experiment was conducted by treating two-year old Rhododendron plants with fungicides on September 2...

Molecular Diagnostics in the Mycosphaerella Leaf Spot Disease Complex of Banana and for Radopholus similis

NARCIS (Netherlands)

Arzanlou, M.; Kema, G.H.J.; Waalwijk, C.; Carlier, I.; Vries, de P.M.; Guzmán, M.; Araya Vargas, M.; Helder, J.; Crous, P.W.

2009-01-01

Mycosphaerella leaf spots and nematodes threaten banana cultivation worldwide. The Mycosphaerella disease complex involves three related ascomycetous fungi: Mycosphaerella fijiensis, M. musicola and M. eumusae. The exact distribution of these three species and their disease epidemiology remain

Epidemiology and Control of Strawberry Bacterial Angular Leaf Spot Disease Caused by Xanthomonas fragariae

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Da-Ran Kim

2016-08-01

Full Text Available Strawberry bacterial angular leaf spot (ALS disease, caused by Xanthomonas fragariae has become increasingly problematic in the strawberry agro-industry. ALS causes small angular water-soaked lesions to develop on the abaxial leaf surface. Studies reported optimum temperature conditions for X. fragariae are 20°C and the pathogen suffers mortality above 32°C. However, at the nursery stage, disease symptoms have been observed under high temperature conditions. In the present study, results showed X. fragariae transmission was via infected maternal plants, precipitation, and sprinkler irrigation systems. Systemic infections were detected using X. fragariae specific primers 245A/B and 295A/B, where 300-bp and 615-bp were respectively amplified. During the nursery stage (from May to August, the pathogen was PCR detected only in maternal plants, but not in soil or irrigation water through the nursery stage. During the cultivation period, from September to March, the pathogen was detected in maternal plants, progeny, and soil, but not in water. Additionally, un-infected plants, when planted with infected plants were positive for X. fragariae via PCR at the late cultivation stage. Chemical control for X. fragariae with oxolinic acid showed 87% control effects against the disease during the nursery period, in contrast to validamycin-A, which exhibited increased efficacy against the disease during the cultivation stage (control effect 95%. To our knowledge, this is the first epidemiological study of X. fragariae in Korean strawberry fields.

Characterisation and epitypification of Pseudocercospora cladosporioides, the causal organism of Cercospora leaf spot of olives

NARCIS (Netherlands)

Avila, A.; Groenewald, J.Z.; Trapero, A.; Crous, P.W.

2005-01-01

Cercospora leaf spot of olives is a serious defoliating disease attributed to Pseudocercospora cladosporioides. Although the disease is well distributed throughout olive growing regions of the world, its epidemiology and population structure remains unknown. The aim of this study was to establish

Morphological and molecular characterization of Cladosporium cladosporioides species complex causing pecan tree leaf spot.

Science.gov (United States)

Walker, C; Muniz, M F B; Rolim, J M; Martins, R R O; Rosenthal, V C; Maciel, C G; Mezzomo, R; Reiniger, L R S

2016-09-16

The objective of this study was to characterize species of the Cladosporium cladosporioides complex isolated from pecan trees (Carya illinoinensis) with symptoms of leaf spot, based on morphological and molecular approaches. Morphological attributes were assessed using monosporic cultures on potato dextrose agar medium, which were examined for mycelial growth, sporulation, color, and conidia and ramoconidia size. Molecular characterization comprised isolation of DNA and subsequent amplification of the translation elongation factor 1α (TEF-1α) region. Three species of the C. cladosporioides complex were identified: C. cladosporioides, Cladosporium pseudocladosporioides, and Cladosporium subuliforme. Sporulation was the most important characteristic differentiating species of this genus. However, morphological features must be considered together with molecular analysis, as certain characters are indistinguishable between species. TEF-1αcan be effectively used to identify and group isolates belonging to the C. cladosporioides complex. The present study provides an important example of a methodology to ascertain similarity between isolates of this complex causing leaf spot in pecan trees, which should facilitate future pathogenicity studies.

Studies on an X-ray induced crinkled leaf mutant of Trichosanthes anguina L

International Nuclear Information System (INIS)

Datta, Subodh Kumar

1986-01-01

Crinkled leaf mutant isolated in the second generation after treatment with X-ray bred true in subsequent generation. The mutant was a late flowering type with increased percentage of PMC's with chromosomal abnormality and pollen grain sterility. TLC study on phenolic compounds in leaves showed that both the mother line and the mutant had equal number of spots but they differed from each other with respect to four spots. Spot Nos. 2 and 4 of the mother line were absent in the mutant but the latter had two new spots (spot Nos. 11 and 12). The mutant and the mother line also differed from each other in pollen grain morohology. (author)

Inhibition of Xanthomonas fragariae, Causative Agent of Angular Leaf Spot of Strawberry, through Iron Deprivation

Directory of Open Access Journals (Sweden)

Peter Henry

2016-10-01

Full Text Available In commercial production settings, few options exist to prevent or treat angular leaf spot of strawberry, a disease of economic importance and caused by the bacterial pathogen Xanthomonas fragariae (Xfr. In the process of isolating and identifying Xfr bacteria from symptomatic plants, we observed growth inhibition of Xfr by bacterial isolates from the same leaf macerates. Identified as species of Pseudomonas and Rhizobium, these isolates were confirmed to suppress growth of Xfr in agar overlay plates and in microtiter plate cultures, as did our reference strain Pseudomonas putida KT2440. Screening of a transposon mutant library of KT2440 revealed that disruption of the biosynthetic pathway for the siderophore pyoverdine resulted in complete loss of Xfr antagonism, suggesting iron competition as a mode of action. Antagonism could be replicated on plate and in culture by addition of purified pyoverdine or by addition of the chelating agents tannic acid and dipyridyl, while supplementing the medium with iron negated the inhibitory effects of pyoverdine, tannic acid and dipyridyl. When co-inoculated with tannic acid onto strawberry plants, Xfr’s ability to cause foliar symptoms was greatly reduced, suggesting a possible opportunity for iron-based management of angular leaf spot. We discuss our findings in the context of ‘nutritional immunity’, the idea that plant hosts restrict pathogens access to iron, either directly, or indirectly through their associated microbiota.

Late-successional forests and northern spotted owls: how effective is the Northwest Forest Plan?

Science.gov (United States)

Miles Hemstrom; Martin G. Raphael

2000-01-01

This paper describes the late-successional and old-growth forest and the northern spotted owl effectiveness monitoring plans for the Northwest Forest Plan. The effectiveness monitoring plan for late-successional and old-growth forests will track changes in forest spatial distribution, and within-stand structure and composition, and it will predict future trends.

Morphological and molecular characterization, sexual reproduction, and pathogenicity of Setosphaeria rostrata isolates from rice leaf spot.

Science.gov (United States)

Kusai, Nor Azizah; Azmi, Madihah Mior Zakuan; Zainudin, Nur Ain Izzati Mohd; Yusof, Mohd Termizi; Razak, Azmi Abd

2016-09-01

Setosphaeria rostrata, a common plant pathogen causing leaf spot disease, affects a wide range of plant species, mainly grasses. Fungi were isolated from brown spots on rice leaves throughout Peninsular Malaysia, and 45 isolates were identified as Setosphaeria rostrata The isolates were then characterized using morphological and molecular approaches. The mating type was determined using PCR amplification of the mating type alleles, and isolates of opposite mating types were crossed to examine sexual reproduction. Based on nuclear ribosomal DNA ITS1-5.8S-ITS2 region (ITS) and beta-tubulin (BT2) sequences, two phylogenetic trees were constructed using the maximum likelihood method; S. rostrata was clustered in one well-supported clade. Pathogenicity tests showed that S. rostrata isolates are pathogenic, suggesting that it is the cause of the symptoms. Mating-type analyses indicated that three isolates carried the MAT1-1 allele, and the other 42 isolates carried MAT1-2 After isolates with opposite mating types were crossed on Sach's medium and incubated for 3 wk, six crosses produced pseudothecia that contained eight mature ascospores, and 12 other crosses produced numerous pseudothecia with no ascospores. To our knowledge, this is the first report on S. rostrata isolated from leaf spots on rice. © 2016 by The Mycological Society of America.

Studies on an X-ray induced crinkled leaf mutant of Trichosanthes anguina L

Energy Technology Data Exchange (ETDEWEB)

Datta, Subodh Kumar

1986-06-01

Crinkled leaf mutant isolated in the second generation after treatment with X-ray bred true in subsequent generation. The mutant was a late flowering type with increased percentage of PMC's with chromosomal abnormality and pollen grain sterility. TLC study on phenolic compounds in leaves showed that both the mother line and the mutant had equal number of spots but they differed from each other with respect to four spots. Spot Nos. 2 and 4 of the mother line were absent in the mutant but the latter had two new spots (spot Nos. 11 and 12). The mutant and the mother line also differed from each other in pollen grain morohology. 3 figures, 2 tables, 4 refs.

Exobasidium maculosum, a new species causing leaf and fruit spots on blueberry in the southeastern USA and its relationship with other Exobasidium spp. parasitic to blueberry and cranberry.

Science.gov (United States)

Brewer, Marin Talbot; Turner, Ashley N; Brannen, Phillip M; Cline, William O; Richardson, Elizabeth A

2014-01-01

Exobasidium leaf and fruit spot of blueberry (Vaccinium section Cyanococcus) is an emerging disease that has rapidly increased in prevalence throughout the southeastern USA. To determine whether this disease is caused by a new species of Exobasidium, we studied the morphology and phylogenetic relationship of the causal fungus compared with other members of the genus, including the type species E. vaccinii and other species that parasitize blueberry and cranberry (V. macrocarpon). Both scanning electron microscopy and light microscopy were used for morphological characterization. For phylogenetic analyses, we sequenced the large subunit of the rDNA (LSU) from 10 isolates collected from leaf or fruit spots of rabbiteye blueberry (V. virgatum), highbush blueberry (V. corymbosum) and southern highbush blueberry (Vaccinium interspecific hybrid) from Georgia and North Carolina and six isolates from leaf spots of lowbush blueberry (V. angustifolium) from Maine and Nova Scotia, Canada. LSU was sequenced from isolates causing red leaf disease of lowbush blueberry and red leaf spot (E. rostrupii) and red shoot (E. perenne) of cranberry. In addition, LSU sequences from GenBank, including sequences with high similarity to the emerging parasite and from Exobasidium spp. parasitizing other Vaccinium spp. and related hosts, were obtained. All sequences were aligned and subjected to phylogenetic analyses. Results indicated that the emerging parasite in the southeastern USA differs morphologically and phylogenetically from other described species and is described herein as Exobasidium maculosum. Within the southeastern USA, clustering based on host species, host tissue type (leaf or fruit) or geographic region was not detected; however, leaf spot isolates from lowbush blueberry were genetically different and likely represent a unique species. © 2014 by The Mycological Society of America.

First report of Elsinoe leaf and fruit spot and Elsinoe pyri on apple in Denmark

DEFF Research Database (Denmark)

Glazowska, Sylwia Emilia; Schiller, Michaela; Lund, Ole Søgaard

2013-01-01

. The associated pathogen has not previously been identi- fied, but symptoms are identical to those described for el- sinoe leaf and fruit spot (ELFS) caused by the ascomycete, Elsinoe pyri (Scheper et al., 2013). In 2012, DNA from fruit skin of apples was purified from two cultivars, Pigeon fra Juellinge...... (Scheper et al., 2013) were recovered by inoculating Topaz- spot infected fruit skin onto potato dextrose agar. Sequenc- ing of the ITS1-5.8S-ITS2 region revealed two identical 628 bp sequences (GenBank KC928079, KC928080) with 99% sequence identity to the previously published sequences of E. pyri. Our......An apple disease, known as “Topaz spot” in northern Europe (Trapman and Jansonius, 2008) has since year 2000 become widespread in Danish organic apple orchards (Malus domestica). Characteristic symptoms are small spots (black on fruits, brown on leaves) having a silvery-grey cen- tre...

Sibling species of cercospora associated with gray leaf spot of maize.

Science.gov (United States)

Wang, J; Levy, M; Dunkle, L D

1998-12-01

ABSTRACT Monoconidial isolates of the fungus causing gray leaf spot of maize were obtained from diseased leaves collected throughout the United States and analyzed for genetic variability at 111 amplified fragment length polymorphism (AFLP) loci. Cluster analysis revealed two very distinct groups of Cercospora zeae-maydis isolates. Both groups were found to be relatively uniform internally with an average genetic similarity among isolates of approximately 93 and 94%, respectively. The groups were separated from each other by a genetic distance of approximately 80%, a distance greater than that separating each group from the sorghum pathogen, C. sorghi (67 to 70%). Characteristics and dimensions of conidia and conid-iophores produced on infected plants or nutrient media were unreliable criteria for taxonomic differentiation of isolates composing the two groups of C. zeae-maydis. Nucleotide sequences of 5.8S ribosomal DNA (rDNA) and the internal transcribed spacer (ITS) regions were identical within each group but different between the two groups and different from C. sorghi. Restriction fragment length polymorphisms generated by digestion of the 5.8S rDNA and ITS regions with TaqI readily distinguished each group and C. sorghi. Isolates in one group were generally distributed throughout maize-producing regions of the United States; isolates in the other group were localized in the eastern third of the country. Both types were present in the same fields at some locations. The genetic distance based on AFLP profiles and different ITS nucleotide sequences between the two morphologically indistinguishable groups indicate that they are sibling species. Although it is unlikely that breeding for resistance to gray leaf spot will be confounded by local or regional variation in the pathogen, a vigilant approach is warranted, because two pathogenic species exist with unknown abilities to evolve new pathotypes.

A review on threat of gray leaf spot disease of maize in Asia

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Narayan Bahadur Dhami

2015-12-01

Full Text Available Biotic and biotic constraints are yield limiting factors in maize producing regions. Among these gray leaf spot is a yield limiting foliar disease of maize in high land regions of Asia. This review is done from related different national and international journals, thesis, books, research papers etc. The objectives of this review are to become familiar with genetics and inheritance, epidemiology, symptoms and disease management strategies etc. High relative humidity, temperature, minimum tillage and maize monoculture are important factors responsible for disease development. The sibling species of Cercospora zeae-maydis (Tehon and Daniels, 1925 Group I and Group II and Cercospora sorghai var. maydis (Chupp, 1954 are associated with this disease. Pathogens colonize in maize debris. Conidia are the source of inoculums for disease spread. Severe blighting of leaves reduces sugars, stalk lodging and causes premature death of plants resulting in yield losses of up to 100%. Disease management through cultural practices is provisional. The use of fungicides for emergencies is effective however; their prohibitive cost and detrimental effects on the environment are negative consequences. The inheritance of tolerance is quantitative with small additive effects. The introgression of resistant genes among the crosses of resistant germplasm enhances the resistance. The crosses of resistant and susceptible germplasm possess greater stability than the crosses of susceptible and resistant germplasm. The development of gray leaf spot tolerant populations through tolerance breeding principle is an economical and sustainable approach to manage the disease.

Fenton reagent and titanium dioxide nanoparticles as antifungal agents to control leaf spot of sugar beet under field conditions

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Hamza Amany

2016-07-01

Full Text Available In this study, foliar sprays of Fenton solutions (Fenton reaction, Fenton-like reaction and Fenton complex, titanium dioxide (TiO2 and the recommended fungicide (chlorothalonil were estimated in the control of sugar beet leaf spot caused by Cercospora beticola under field conditions in two growing seasons. In addition, the impacts of these treatments on some crop characters (leaf dry weight, root fresh weight, soluble solid content, sucrose content and purity of sugar were examined. Biochemical and histological changes in the livers and kidneys of treated rats compared to an untreated control were utilized to assess the toxicity of the examined curative agents. Overall, chlorothalonil and Fenton complex were the most effective treatments for disease suppression in both tested seasons followed by Fenton-like reagent, Fenton’s reagent and TiO2, respectively. Growth and yield characters of treated sugar beet significantly increased in comparison to an untreated control. There were mild or no (biochemical and histological changes in the livers and kidneys of treated rats compared to the control. Fenton solutions and TiO2 may offer a new alternative for leaf spot control in sugar beet.

The disease prevalence and severity of Cercospora leaf spot in sugar beet cultivations in Kayseri

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Hacer Handan ALTINOK

2012-12-01

Full Text Available Cercospora leaf spot disease (Cercospora beticola Sacc., is one of the most economically important fungal diseases in sugar beet growing. Under appropriate climatic conditions, the disease can reach epidemic levels. Although some fungicides exist for disease control, resistance development by pathogen against fungicides is creating difficulties. Besides, use of resistant varieties which is considered as the most efficient and environment-friendly method is adversely affected by pathogen’s ability to exhibit high genetic variations and varying resistance levels against different races of pathogen restricts the success of resistance breeding studies. In order to reveal status of this disease in Kayseri province, surveys were conducted in 2010 and 2011 in sugar beet growing areas and disease prevalence and severity were determined. Approximately, 1500 da area in 90 fields were examined and about 700 da of this area found as infected with Cercospora leaf spot disease in both years of the survey. Highest disease prevalence and severity were found as 80 % and 45 %, respectively, in Sarıoğlan district, which is followed by central district, Develi and Bünyan. Among surveyed districts, lowest prevalence and severity were detected as approx. 65 % and 35 %, respectively, in Yeşilhisar.

Regression and artificial neural network modeling for the prediction of gray leaf spot of maize.

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Paul, P A; Munkvold, G P

2005-04-01

ABSTRACT Regression and artificial neural network (ANN) modeling approaches were combined to develop models to predict the severity of gray leaf spot of maize, caused by Cercospora zeae-maydis. In all, 329 cases consisting of environmental, cultural, and location-specific variables were collected for field plots in Iowa between 1998 and 2002. Disease severity on the ear leaf at the dough to dent plant growth stage was used as the response variable. Correlation and regression analyses were performed to select potentially useful predictor variables. Predictors from the best 9 of 80 regression models were used to develop ANN models. A random sample of 60% of the cases was used to train the networks, and 20% each for testing and validation. Model performance was evaluated based on coefficient of determination (R(2)) and mean square error (MSE) for the validation data set. The best models had R(2) ranging from 0.70 to 0.75 and MSE ranging from 174.7 to 202.8. The most useful predictor variables were hours of daily temperatures between 22 and 30 degrees C (85.50 to 230.50 h) and hours of nightly relative humidity >/=90% (122 to 330 h) for the period between growth stages V4 and V12, mean nightly temperature (65.26 to 76.56 degrees C) for the period between growth stages V12 and R2, longitude (90.08 to 95.14 degrees W), maize residue on the soil surface (0 to 100%), planting date (in day of the year; 112 to 182), and gray leaf spot resistance rating (2 to 7; based on a 1-to-9 scale, where 1 = most susceptible to 9 = most resistant).

Species of Cercospora associated with grey leaf spot of maize.

Science.gov (United States)

Crous, Pedro W; Groenewald, Johannes Z; Groenewald, Marizeth; Caldwell, Pat; Braun, Uwe; Harrington, Thomas C

2006-01-01

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the internal transcribed spacers (ITS1 & ITS2), the 5.8S rRNA gene, elongation factor 1-alpha, histone H3, actin and calmodulin gene regions suggest that Groups I and II are two distinct species. Furthermore, Cercospora zeae-maydis (Group I) can be distinguished from C. zeina sp. nov. (Group II) by its faster growth rate on artificial media, the ability to produce cercosporin, longer conidiophores, and broadly fusiform conidia. A PCR-based test that distinguishes the two species was developed using species-specific primers designed from the histone H3 gene.

REVOLUTA and WRKY53 connect early and late leaf development in Arabidopsis

DEFF Research Database (Denmark)

Xie, Yakun; Huhn, Kerstin; Brandt, Ronny

2014-01-01

As sessile organisms, plants have to continuously adjust growth and development to ever-changing environmental conditions. At the end of the growing season, annual plants induce leaf senescence to reallocate nutrients and energy-rich substances from the leaves to the maturing seeds. Thus, leaf se...... of WRKY53 in response to oxidative stress, and mutations in HD-ZIPIII genes strongly delay the onset of senescence. Thus, a crosstalk between early and late stages of leaf development appears to contribute to reproductive success.......As sessile organisms, plants have to continuously adjust growth and development to ever-changing environmental conditions. At the end of the growing season, annual plants induce leaf senescence to reallocate nutrients and energy-rich substances from the leaves to the maturing seeds. Thus, leaf...... senescence is a means with which to increase reproductive success and is therefore tightly coupled to the developmental age of the plant. However, senescence can also be induced in response to sub-optimal growth conditions as an exit strategy, which is accompanied by severely reduced yield. Here, we show...

The inheritance of resistance to bacterial leaf spot of lettuce caused by Xanthomonas campestris pv. vitians in three lettuce cultivars

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Lettuce yields can be reduced by the disease bacterial leaf spot (BLS) caused by the pathogen Xanthomonas campestris pv. vitians (Xcv) and host resistance is the most feasible method to reduce disease losses. The cultivars La Brillante, Pavane, and Little Gem express an incompatible host-pathogen in...

Occurrence of angular leaf spot caused by Pseudocercospora griseola in Phaseolus vulgaris in Asturias, Spain

Energy Technology Data Exchange (ETDEWEB)

Landeras, E.; Trapiello, E.; Braña, M.; González, A.J.

2017-07-01

Angular leaf spot (ALS) symptoms were observed in 2015 in common bean fields at four locations in Asturias, NW Spain. This disease is frequent in tropical areas and we have no record of its presence in our region, at least in the last 30 years. However, since its detection its presence in the crops has been increasing. Symptoms were necrotic spots on leaves and reddish-brown to black circular spots on pods, stems, branches and petioles. The damage observed in the mentioned crops was highly variable (between 60% and 100% affected leaves), being most severe in crops where no agrochemical treatment were applied. Three strains were selected and identified based in morphological features as Pseudocercospora griseola. The ITS region was amplified by PCR obtaining a sequence that was identical for the three isolates (Acc. No. LT222499). This sequence showed 99-100% similarity with those deposited in databases corresponding to P. griseola. To fulfill Koch's postulates, a pathogenicity test was carried out in two common bean cultivars (‘Andecha’ and ‘Maruxina’). P. griseola was re-isolated from inoculated plants and not from control plants. In cv. ‘Andecha’, chlorosis was observed in all the inoculated plants, before the appearance of spots. Consequently this is the first confirmed report of this pathogen in our region.

Fitness and competition studies of QoI resistant and sensitive Cercospora sojina isolates, the causal agent of frogeye leaf spot

Science.gov (United States)

Frogeye leaf spot (FLS), caused by Cercospora sojina, is a yearly foliar disease of soybean in Tennessee and causes substantial economic losses if not properly managed. Quinone outside inhibitor (QoI) fungicides are often used to manage FLS, but C. sojina isolates have developed resistance to this c...

Characterization of Apricot pseudo-chlorotic leaf spot virus, A Novel Trichovirus Isolated from Stone Fruit Trees.

Science.gov (United States)

Liberti, D; Marais, A; Svanella-Dumas, L; Dulucq, M J; Alioto, D; Ragozzino, A; Rodoni, B; Candresse, T

2005-04-01

ABSTRACT A trichovirus closely related to Apple chlorotic leaf spot virus (ACLSV) was detected in symptomatic apricot and Japanese plum from Italy. The Sus2 isolate of this agent cross-reacted with anti-ACLSV polyclonal reagents but was not detected by broad-specificity anti- ACLSV monoclonal antibodies. It had particles with typical trichovirus morphology but, contrary to ACLSV, was unable to infect Chenopodium quinoa and C. amaranticolor. The sequence of its genome (7,494 nucleotides [nt], missing only approximately 30 to 40 nt of the 5' terminal sequence) and the partial sequence of another isolate were determined. The new virus has a genomic organization similar to that of ACLSV, with three open reading frames coding for a replication-associated protein (RNA-dependent RNA polymerase), a movement protein, and a capsid protein, respectively. However, it had only approximately 65 to 67% nucleotide identity with sequenced isolates of ACLSV. The differences in serology, host range, genome sequence, and phylogenetic reconstructions for all viral proteins support the idea that this agent should be considered a new virus, for which the name Apricot pseudo-chlorotic leaf spot virus (APCLSV) is proposed. APCLSV shows substantial sequence variability and has been recovered from various Prunus sources coming from seven countries, an indication that it is likely to have a wide geographical distribution.

Association analysis of bacterial leaf spot resistance and SNP markers derived from expressed sequence tags (ESTs) in lettuce (Lactuca sativa L.)

Science.gov (United States)

Bacterial leaf spot of lettuce, caused by Xanthomonas campestris pv. vitians, is a devastating disease of lettuce worldwide. Since there are no chemicals available for effective control of the disease, host-plant resistance is highly desirable to protect lettuce production. A total of 179 lettuce ge...

Fine mapping of a quantitative resistance gene for gray leaf spot of maize (Zea mays L.) derived from teosinte (Z. mays ssp. parviglumis).

Science.gov (United States)

Zhang, Xinye; Yang, Qin; Rucker, Elizabeth; Thomason, Wade; Balint-Kurti, Peter

2017-06-01

In this study we mapped the QTL Qgls8 for gray leaf spot (GLS) resistance in maize to a ~130 kb region on chromosome 8 including five predicted genes. In previous work, using near isogenic line (NIL) populations in which segments of the teosinte (Zea mays ssp. parviglumis) genome had been introgressed into the background of the maize line B73, we had identified a QTL on chromosome 8, here called Qgls8, for gray leaf spot (GLS) resistance. We identified alternate teosinte alleles at this QTL, one conferring increased GLS resistance and one increased susceptibility relative to the B73 allele. Using segregating populations derived from NIL parents carrying these contrasting alleles, we were able to delimit the QTL region to a ~130 kb (based on the B73 genome) which encompassed five predicted genes.

Essential Oil of Cymbopogon citratus on the Control of the Curvularia Leaf Spot Disease on Maize

Science.gov (United States)

Mourão, Dalmarcia de Sousa Carlos; Ferreira de Souza Pereira, Talita; de Souza, Danival José; Chagas Júnior, Aloísio Freitas; Veloso, Ronice Alves; Leão, Evelynne Urzêdo

2017-01-01

The Curvularia Leaf Spot is becoming more common due to the culture expansion and the low resistance of the cultivated genotypes in tropical regions. Thus, the objective was to evaluate the fungitoxicity of the essential oil of Cymbopogon citratus upon the phytopathogen Curvularia lunata, causative agent of the Curvularia Leaf Spot. There was realized pathogenicity tests of C. lunata in maize plants, phytotoxicity of the essential oil of C. citratus and gas chromatography attached, germination tests of the conidia, and of in vitro inhibition of C. lunata. Also, there were realized tests aiming at verifying the phytopathogen control in vivo. In the pathogenicity tests, there were verified symptoms of the disease in all of the suspensions tested on plants. It was observed that the essential oil concentrations of 7.5 µL mL−1 to 50 µL mL−1 were phytotoxic. The majoritarian chemical components of the essential oil of C. citratus were Geranial (41.46%) and Neral (32.43%). The concentrations of 5 and 7.5 µL mL−1 inhibited 100% of conidia germination. None of the concentrations evaluated effectively inhibited C. lunata mycelial growth in in vitro tests. In the preventive control, the concentration of 7.5 µL mL−1 was sufficient for the reduction of the progress of the disease, however the curative control was not efficient on the tested dosages. PMID:28930276

New Generation of Resistant Sugar Beet Varieties for Advanced Integrated Management of Cercospora Leaf Spot in Central Europe

OpenAIRE

Johannes Vogel; Johannes Vogel; Christine Kenter; Carsten Holst; Bernward Märländer

2018-01-01

Cercospora leaf spot (CLS) epidemics in sugar beet have been increasing in recent years causing higher use of fungicides. Concomitantly, the availability of effective fungicides is at risk because of resistance development in the fungus, the lack of new active ingredients as well as restrictive approval practices. A key option for an integrated management of CLS is cultivation of resistant varieties. Because of the yield penalty in resistant varieties, acceptance in commercial practice so far...

Diallel analysis of leaf disease resistance in inbred Brazilian popcorn cultivars.

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Vieira, R A; Scapim, C A; Moterle, L M; Tessmann, D J; Conrado, T V; Amaral Júnior, A T

2009-12-01

We estimated general and specific combining abilities and examined resistance to northern leaf blight (Exserohilum turcicum) and to gray leaf spot (Cercospora zeae-maydis) in a set of nine inbred popcorn lines. These inbreds were crossed in a complete diallel scheme without reciprocals, which produced 36 F(1) hybrids. Two experiments with a square lattice design and three replications were conducted during the 2008/2009 crop season, in Maringá, PR, Brazil. The severity of northern leaf blight and gray leaf spot was assessed under natural infestation conditions. Data were examined by individual and joint analysis of variance. Individual and joint Griffing's diallel analyses were carried out for adjusted means. General combining ability and specific combining ability were significant (P < 0.10) by the F-test for northern leaf blight and gray leaf spot infestation levels. This denotes that additive and non-additive gene effects both contributed to resistance to these diseases, but that the additive gene effects were more important. Among the inbred lines, P(8) and P(9) gave the highest resistance to northern leaf blight, and P(3) and P(4.3) gave the highest resistance to gray leaf spot. The hybrids P(7.4) x P(8) and P(4.3) x P(9) could be exploited by reciprocal recurrent selection to provide genotypes with both northern leaf blight and gray leaf spot resistance. Significant interaction between general combining ability and crop season (P < 0.10) denotes the importance of environment, even though the disease levels in the hybrids were quite consistent.

Biocontrol Potential of Streptomyces hydrogenans strain DH16 Towards Alternaria brassicicola to Control Damping Off and Black Leaf Spot of Raphanus sativus

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Rajesh Kumari Manhas

2016-12-01

Full Text Available Biocontrol agents and their bioactive metabolites provide one of the best alternatives to decrease the use of chemical pesticides. In light of this, the present investigation reports the biocontrol potential of Streptomyces hydrogenans DH16 and its metabolites towards Alternaria brassicicola, causal agent of black leaf spot and damping off of seedlings of crucifers. In vitro antibiosis of strain against pathogen revealed complete suppression of mycelial growth of pathogen, grown in potato dextrose broth supplemented with culture supernatant (20% v/v of Streptomyces hydrogenans DH16. Microscopic examination of the fungal growth showed severe morphological abnormalities in the mycelium caused by antifungal metabolites. In vivo studies showed the efficacy of streptomycete cells and culture supernatant as seed dressings to control damping off of Raphanus sativus seedlings. Treatment of pathogen infested seeds with culture supernatant (10% and streptomycete cells significantly improved seed germination (75-80% and vigour index (1167-1538. Furthermore, potential of cells and culture supernatant as foliar treatment to control black leaf spot was also evaluated. Clearly visible symptoms of disease were observed in the control plants with 66.81% disease incidence and retarded growth of root system. However, disease incidence reduced to 6.78 and 1.47% in plants treated with antagonist and its metabolites, respectively. Additionally, treatment of seeds and plants with streptomycete stimulated various growth traits of plants over uninoculated control plants in the absence of pathogen challenge. These results indicate that S. hydrogenans and its culture metabolites can be developed as biofungicides as seed dressings to control seed borne pathogens, and as sprays to control black leaf spot of crucifers.

Salicylic acid confers enhanced resistance to Glomerella leaf spot in apple.

Science.gov (United States)

Zhang, Ying; Shi, Xiangpeng; Li, Baohua; Zhang, Qingming; Liang, Wenxing; Wang, Caixia

2016-09-01

Glomerella leaf spot (GLS) caused by Glomerella cingulata is a newly emergent disease that results in severe defoliation and fruit spots in apple. Currently, there are no effective means to control this disease except for the traditional fungicide sprays. Induced resistance by elicitors against pathogens infection is a widely accepted eco-friendly strategy. In the present study, we investigated whether exogenous application of salicylic acid (SA) could improve resistance to GLS in a highly susceptible apple cultivar (Malus domestica Borkh. cv. 'Gala') and the underlying mechanisms. The results showed that pretreatment with SA, at 0.1-1.0 mM, induced strong resistance against GLS in 'Gala' apple leaves, with SA treated leaves showing significant reduction in lesion numbers and disease index. Concurrent with the enhanced disease resistance, SA treatment markedly increased the total antioxidant capacity (T-AOC) and defence-related enzyme activities, including catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO). As expected, SA treatment also induced the expression levels of five pathogenesis-related (PR) genes including PR1, PR5, PR8, Chitinase and β-1,3-glucanase. Furthermore, the most pronounced and/or rapid increase was observed in leaves treated with SA and subsequently inoculated with G. cingulata compared to the treatment with SA or inoculation with the pathogen. Together, these results suggest that exogenous SA triggered increase in reactive oxygen species levels and the antioxidant system might be responsible for enhanced resistance against G. cingulata in 'Gala' apple leaves. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Fine mapping of a quantitative resistance gene for gray leaf spot of maize (Zea mays L.) derived from teosinte (Z. mays ssp. parviglumis)

Science.gov (United States)

In previous work, using near isogenic line (NIL) populations in which segments of the tesosinte (Zea mays ssp. parviglumis) genome had been introgressed into the background of the maize line B73, we had identified a QTL on chromosome 8, here called Qgls8, for gray leaf spot resistance. We identified...

Identification of Causes of Red Leaf Spot on Red Jabon (Anthocephalus macrophyllus (Roxb. Havil Seeds in Kima Atas Permanent Nursery, Manado Forestry Research Institute

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Hanif Nurul Hidayah

2015-12-01

Full Text Available Fulfillment the needs of Red Jabon (Anthocephalus macrophyllus (Roxb. Havil seeds on the other hand can create an unbalanced ecosystem. The availability of red Jabon seed was becoming a source of food for pests, then it causes an explosion of pests and pathogens. The disease that most often affect red Jabon seeds, both in the nursery and in the field was red leaf spot (antraknose. The initial step to control red leaf spot disease is the identification of causing. Identification method performed by observation of the symptoms in the field, followed by microscopic observation in a laboratory. Based on the identification result, it was known that the disease caused by the fungus Cercospora sp., Colletotrichum sp. and Pestalotia sp. The effect caused by those fungal pathogens was the disruption of the photosynthetic process that ultimately inhibits the growth of red Jabon seeds. The controls which have been done are arranged the watering intensity, isolated the infected seed,and applied the chemical fungicide.

Screening of Potential Inhibitor against Coat Protein of Apple Chlorotic Leaf Spot Virus.

Science.gov (United States)

Purohit, Rituraj; Kumar, Sachin; Hallan, Vipin

2018-06-01

In this study, we analyzed Coat protein (CP) of Apple chlorotic leaf spot virus (ACLSV), an important latent virus on Apple. Incidence of the virus is upto 60% in various apple cultivars, affecting yield losses of the order of 10-40% (depending upon the cultivar). CP plays an important role as the sole building block of the viral capsid. Homology approach was used to model 193 amino acid sequence of the coat protein. We used various servers such as ConSurf, TargetS, OSML, COACH, COFACTOR for the prediction of active site residues in coat protein. Virtual screening strategy was employed to search potential inhibitors for CP. Top twenty screened molecules considered for drugability, and toxicity analysis and one potential molecule was further analyzed by docking analysis. Here, we reported a potent molecule which could inhibit the formation of viron assembly by targeting the CP protein of virus.

Leaf-morphology-assisted selection for resistance to two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in carnations (Dianthus caryophyllus L).

Science.gov (United States)

Seki, Kousuke

2016-10-01

The development of a cultivar resistant to the two-spotted spider mite has provided both ecological and economic benefits to the production of cut flowers. This study aimed to clarify the mechanism of resistance to mites using an inbred population of carnations. In the resistant and susceptible plants selected from an inbred population, a difference was recognised in the thickness of the abaxial palisade tissue by microscopic examination of the damaged leaf. Therefore, it was assumed that mites displayed feeding preferences within the internal leaf structure of the carnation leaf. The suitability of the host plant for mites was investigated using several cultivars selected using an index of the thickness from the abaxial leaf surface to the spongy tissue. The results suggested that the cultivar associated with a thicker abaxial tissue lowered the intrinsic rate of natural increase of the mites. The cultivars with a thicker abaxial tissue of over 120 µm showed slight damage in the field test. The ability of mites to feed on the spongy tissue during an early life stage from hatching to adult emergence was critical. It was possible to select a cultivar that is resistant to mites under a real cultivation environment by observing the internal structure of the leaf. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Genetic diversity and apple leaf spot disease resistance characterization assessed by SSR markers

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Gustavo H.F. Klabunde

2016-09-01

Full Text Available Among the cultivation problems of apple production in Brazil, Apple Leaf Spot (ALS disease represents one of the main breeding challenges. This study aims at analyzing the genetic diversity among 152 apple scion accessions available at the Apple Gene Bank of EPAGRI, located in Caçador, Santa Catarina/ Brazil. Eleven genomic SSR loci were analyzed to assess genetic diversity of ALS resistant and susceptible accessions. Results revealed high genetic diversity of the studied accessions, being 120 exclusive alleles (67 unique from scion accessions resistant to ALS, and a mean PIC of 0.823. The locus Probability of Identity (I ranged from 0.017 to 0.089. The combined I was 4.11 x 10-16, and the Power of Exclusion was 99.99999259%. In addition, the DNA fingerprint patterns will contribute as additional descriptors to select parental for crosses and early identification of apple accessions for breeding purposes, and also for cultivar protection.

Contribution of the drought tolerance-related Stress-responsive NAC1 transcription factor to resistance of barley to Ramularia leaf spot

OpenAIRE

MCGRANN, GRAHAM R D; STEED, ANDREW; BURT, CHRISTOPHER; GODDARD, RACHEL; LACHAUX, CLEA; BANSAL, ANURADHA; CORBITT, MARGARET; GORNIAK, KALINA; NICHOLSON, PAUL; BROWN, JAMES K M

2014-01-01

NAC proteins are plant transcription factors that are involved in tolerance to abiotic and biotic stresses, as well as in many developmental processes. Stress-responsive NAC1 (SNAC1) transcription factor is involved in drought tolerance in barley and rice, but has not been shown previously to have a role in disease resistance. Transgenic over-expression of HvSNAC1 in barley cv. Golden Promise reduced the severity of Ramularia leaf spot (RLS), caused by the fungus Ramularia collo-cygni, but ha...

QTL mapping of resistance to gray leaf spot in maize.

Science.gov (United States)

Zhang, Yan; Xu, Ling; Fan, Xingming; Tan, Jing; Chen, Wei; Xu, Mingliang

2012-12-01

Gray leaf spot (GLS), caused by the causal fungal pathogen Cercospora zeae-maydis, is one of the most serious foliar diseases of maize worldwide. In the current study, a highly resistant inbred line Y32 and a susceptible line Q11 were used to produce segregating populations for both genetic analysis and QTL mapping. The broad-sense heritability (H (2)) for GLS resistance was estimated to be as high as 0.85, indicating that genetic factors played key roles in phenotypic variation. In initial QTL analysis, four QTL, located on chromosomes 1, 2, 5, and 8, were detected to confer GLS resistance. Each QTL could explain 2.53-23.90 % of the total phenotypic variation, predominantly due to additive genetic effects. Two major QTL, qRgls1 and qRgls2 on chromosomes 8 and 5, were consistently detected across different locations and replicates. Compared to the previous results, qRgls2 is located in a 'hotspot' for GLS resistance; while, qRgls1 does not overlap with any other known resistance QTL. Furthermore, the major QTL-qRgls1 was fine-mapped into an interval of 1.4 Mb, flanked by the markers GZ204 and IDP5. The QTL-qRgls1 could enhance the resistance percentages by 19.70-61.28 %, suggesting its usefulness to improve maize resistance to GLS.

High-density genetic map using whole-genome re-sequencing for fine mapping and candidate gene discovery for disease resistance in peanut

Science.gov (United States)

High-density genetic linkage maps are essential for fine mapping QTLs controlling disease resistance traits, such as early leaf spot (ELS), late leaf spot (LLS), and Tomato spotted wilt virus (TSWV). With completion of the genome sequences of two diploid ancestors of cultivated peanut, we could use ...

Working Towards Disease Resistance in Peanuts Through Biotechnology

Science.gov (United States)

Resistant cultivars are the most desirable approach to disease control in agriculture. Early and late leaf spot are the most important foliar diseases of peanut worldwide. Significant progress for leaf spot resistance in peanut can be achieved through biotechnology. The National Peanut Research ...

Characterization of rust, early and late leaf spot resistance in wild and cultivated peanut germplasm Caracterização da resistência à ferrugem, mancha preta e mancha castanha em germoplasma silvestre e cultivado de amendoim

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Alessandra Pereira Fávero

2009-02-01

Full Text Available Groundnut (Arachis hypogaea has an AB genome and is one of the most important oil crops in the world. The main constraints of crop management in Brazil are fungal diseases. Several species of the genus Arachis are resistant to pests and diseases. The objective of our experiments was to identify wild species belonging to the taxonomic section Arachis with either A or B (or " non-A" genomes that are resistant to early leaf spot (Cercospora arachidicola, late leaf spot (Cercosporidium personatum and rust (Puccinia arachidis. For the identification of genotypes resistant to fungal diseases, bioassays with detached leaves were done in laboratory conditions, with artificial inoculation, a controlled temperature of 25ºC and a photoperiod of 10 h light/14 h dark, for 20-42 days, depending on the fungi species. Most of the accessions of wild species were more resistant than accessions of A. hypogaea for one, two or all three fungi species studied. Arachis monticola, considered to be a possible tetraploid ancestor or a derivative of A. hypogaea, was also more susceptible to Cercosporidium personatum and Puccinia arachidis, as compared to most of the wild species. Therefore, wild germplasm accessions of both genome types are available to be used for the introgression of resistance genes against three fungal diseases of peanut.O amendoim (Arachis hypogaea possui genoma AB e é uma das mais importantes culturas oleaginosas em todo o mundo. Os principais problemas da cultura no Brasil são as doenças fúngicas. Várias espécies do gênero Arachis são resistentes a pragas e doenças. Este trabalho visou a identificar espécies silvestres pertencentes à seção Arachis associadas aos genomas A ou B (ou " não-A" do amendoim que são resistentes à mancha castanha (Cercospora arachidicola, mancha preta (Cercosporidium personatum e ferrugem (Puccinia arachidis. Para a identificação de genótipos resistentes a doenças fúngicas, bioensaios utilizando

Asparagus Beetle and Spotted Asparagus Beetle

OpenAIRE

Hodgson, Erin W.; Drost, Dan

2007-01-01

Asparagus beetle, Crioceris asparagi, and spotted asparagus beetle, C. duodecimpunctata are leaf beetles in the family Chrysomelidae. These beetles feed exclusively on asparagus and are native to Europe. Asparagus beetle is the more economically injurious of the two species.

Characterizing and Estimating Fungal Disease Severity of Rice Brown Spot with Hyperspectral Reflectance Data

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Zhan-yu LIU

2008-09-01

Full Text Available Large-scale farming of agriculture crops requires real-time detection of disease for field pest management. Hyperspectral remote sensing data generally have high spectral resolution, which could be very useful for detecting disease stress in green vegetation at the leaf and canopy levels. In this study, hyperspectral reflectances of rice in the laboratory and field were measured to characterize the spectral regions and wavebands, which were the most sensitive to rice brown spot infected by Bipolaris oryzae (Helminthosporium oryzae Breda. de Hann. Leaf reflectance increased at the ranges of 450 to 500 nm and 630 to 680 nm with the increasing percentage of infected leaf surface, and decreased at the ranges of 520 to 580 nm, 760 to 790 nm, 1550 to 1750 nm, and 2080 to 2350 nm with the increasing percentage of infected leaf surface respectively. The sensitivity analysis and derivative technique were used to select the sensitive wavebands for the detection of rice brown spot infected by B. oryzae. Ratios of rice leaf reflectance were evaluated as indicators of brown spot. R669/R746 (the reflectance at 669 nm divided by the reflectance at 746 nm, the following ratios may be deduced by analogy, R702/R718, R692/R530, R692/R732, R535/R746, R521/R718, and R569/R718 increased significantly as the incidence of rice brown spot increased regardless of whether it's at the leaf or canopy level. R702/R718, R692/R530, R692/R732 were the best three ratios for estimating the disease severity of rice brown spot at the leaf and canopy levels. This result not only confirms the capability of hyperspectral remote sensing data in characterizing crop disease for precision pest management in the real world, but also testifies that the ratios of crop reflectance is a useful method to estimate crop disease severity.

Using SNP genetic markers to elucidate the linkage of the Co-34/Phg-3 anthracnose and angular leaf spot resistance gene cluster with the Ur-14 resistance gene

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The Ouro Negro common bean cultivar contains the Co-34/Phg-3 gene cluster that confers resistance to the anthracnose (ANT) and angular leaf spot (ALS) pathogens. These genes are tightly linked on chromosome 4. Ouro Negro also has the Ur-14 rust resistance gene, reportedly in the vicinity of Co- 34; ...

Genome-Wide Association Studies of Anthracnose and Angular Leaf Spot Resistance in Common Bean (Phaseolus vulgaris L..

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Juliana Morini Küpper Cardoso Perseguini

Full Text Available The common bean (Phaseolus vulgaris L. is the world's most important legume for human consumption. Anthracnose (ANT; Colletotrichum lindemuthianum and angular leaf spot (ALS; Pseudocercospora griseola are complex diseases that cause major yield losses in common bean. Depending on the cultivar and environmental conditions, anthracnose and angular leaf spot infections can reduce crop yield drastically. This study aimed to estimate linkage disequilibrium levels and identify quantitative resistance loci (QRL controlling resistance to both ANT and ALS diseases of 180 accessions of common bean using genome-wide association analysis. A randomized complete block design with four replicates was performed for the ANT and ALS experiments, with four plants per genotype in each replicate. Association mapping analyses were performed for ANT and ALS using a mixed linear model approach implemented in TASSEL. A total of 17 and 11 significant statistically associations involving SSRs were detected for ANT and ALS resistance loci, respectively. Using SNPs, 21 and 17 significant statistically associations were obtained for ANT and angular ALS, respectively, providing more associations with this marker. The SSR-IAC167 and PvM95 markers, both located on chromosome Pv03, and the SNP scaffold00021_89379, were associated with both diseases. The other markers were distributed across the entire common bean genome, with chromosomes Pv03 and Pv08 showing the greatest number of loci associated with ANT resistance. The chromosome Pv04 was the most saturated one, with six markers associated with ALS resistance. The telomeric region of this chromosome showed four markers located between approximately 2.5 Mb and 4.4 Mb. Our results demonstrate the great potential of genome-wide association studies to identify QRLs related to ANT and ALS in common bean. The results indicate a quantitative and complex inheritance pattern for both diseases in common bean. Our findings will

Genome-Wide Association Studies of Anthracnose and Angular Leaf Spot Resistance in Common Bean (Phaseolus vulgaris L.).

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Perseguini, Juliana Morini Küpper Cardoso; Oblessuc, Paula Rodrigues; Rosa, João Ricardo Bachega Feijó; Gomes, Kleber Alves; Chiorato, Alisson Fernando; Carbonell, Sérgio Augusto Morais; Garcia, Antonio Augusto Franco; Vianello, Rosana Pereira; Benchimol-Reis, Luciana Lasry

2016-01-01

The common bean (Phaseolus vulgaris L.) is the world's most important legume for human consumption. Anthracnose (ANT; Colletotrichum lindemuthianum) and angular leaf spot (ALS; Pseudocercospora griseola) are complex diseases that cause major yield losses in common bean. Depending on the cultivar and environmental conditions, anthracnose and angular leaf spot infections can reduce crop yield drastically. This study aimed to estimate linkage disequilibrium levels and identify quantitative resistance loci (QRL) controlling resistance to both ANT and ALS diseases of 180 accessions of common bean using genome-wide association analysis. A randomized complete block design with four replicates was performed for the ANT and ALS experiments, with four plants per genotype in each replicate. Association mapping analyses were performed for ANT and ALS using a mixed linear model approach implemented in TASSEL. A total of 17 and 11 significant statistically associations involving SSRs were detected for ANT and ALS resistance loci, respectively. Using SNPs, 21 and 17 significant statistically associations were obtained for ANT and angular ALS, respectively, providing more associations with this marker. The SSR-IAC167 and PvM95 markers, both located on chromosome Pv03, and the SNP scaffold00021_89379, were associated with both diseases. The other markers were distributed across the entire common bean genome, with chromosomes Pv03 and Pv08 showing the greatest number of loci associated with ANT resistance. The chromosome Pv04 was the most saturated one, with six markers associated with ALS resistance. The telomeric region of this chromosome showed four markers located between approximately 2.5 Mb and 4.4 Mb. Our results demonstrate the great potential of genome-wide association studies to identify QRLs related to ANT and ALS in common bean. The results indicate a quantitative and complex inheritance pattern for both diseases in common bean. Our findings will contribute to more

Transcriptional analyses of natural leaf senescence in maize.

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Wei Yang Zhang

Full Text Available Leaf senescence is an important biological process that contributes to grain yield in crops. To study the molecular mechanisms underlying natural leaf senescence, we harvested three different developmental ear leaves of maize, mature leaves (ML, early senescent leaves (ESL, and later senescent leaves (LSL, and analyzed transcriptional changes using RNA-sequencing. Three sets of data, ESL vs. ML, LSL vs. ML, and LSL vs. ESL, were compared, respectively. In total, 4,552 genes were identified as differentially expressed. Functional classification placed these genes into 18 categories including protein metabolism, transporters, and signal transduction. At the early stage of leaf senescence, genes involved in aromatic amino acids (AAAs biosynthetic process and transport, cellular polysaccharide biosynthetic process, and the cell wall macromolecule catabolic process, were up-regulated. Whereas, genes involved in amino acid metabolism, transport, apoptosis, and response to stimulus were up-regulated at the late stage of leaf senescence. Further analyses reveals that the transport-related genes at the early stage of leaf senescence potentially take part in enzyme and amino acid transport and the genes upregulated at the late stage are involved in sugar transport, indicating nutrient recycling mainly takes place at the late stage of leaf senescence. Comparison between the data of natural leaf senescence in this study and previously reported data for Arabidopsis implies that the mechanisms of leaf senescence in maize are basically similar to those in Arabidopsis. A comparison of natural and induced leaf senescence in maize was performed. Athough many basic biological processes involved in senescence occur in both types of leaf senescence, 78.07% of differentially expressed genes in natural leaf senescence were not identifiable in induced leaf senescence, suggesting that differences in gene regulatory network may exist between these two leaf senescence

High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases.

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Valentini, Giseli; Gonçalves-Vidigal, Maria Celeste; Hurtado-Gonzales, Oscar P; de Lima Castro, Sandra Aparecida; Cregan, Perry B; Song, Qijian; Pastor-Corrales, Marcial A

2017-08-01

Co-segregation analysis and high-throughput genotyping using SNP, SSR, and KASP markers demonstrated genetic linkage between Ur-14 and Co-3 4 /Phg-3 loci conferring resistance to the rust, anthracnose and angular leaf spot diseases of common bean. Rust, anthracnose, and angular leaf spot are major diseases of common bean in the Americas and Africa. The cultivar Ouro Negro has the Ur-14 gene that confers broad spectrum resistance to rust and the gene cluster Co-3 4 /Phg-3 containing two tightly linked genes conferring resistance to anthracnose and angular leaf spot, respectively. We used co-segregation analysis and high-throughput genotyping of 179 F 2:3 families from the Rudá (susceptible) × Ouro Negro (resistant) cross-phenotyped separately with races of the rust and anthracnose pathogens. The results confirmed that Ur-14 and Co-3 4 /Phg-3 cluster in Ouro Negro conferred resistance to rust and anthracnose, respectively, and that Ur-14 and the Co-3 4 /Phg-3 cluster were closely linked. Genotyping the F 2:3 families, first with 5398 SNPs on the Illumina BeadChip BARCBEAN6K_3 and with 15 SSR, and eight KASP markers, specifically designed for the candidate region containing Ur-14 and Co-3 4 /Phg-3, permitted the creation of a high-resolution genetic linkage map which revealed that Ur-14 was positioned at 2.2 cM from Co-3 4 /Phg-3 on the short arm of chromosome Pv04 of the common bean genome. Five flanking SSR markers were tightly linked at 0.1 and 0.2 cM from Ur-14, and two flanking KASP markers were tightly linked at 0.1 and 0.3 cM from Co-3 4 /Phg-3. Many other SSR, SNP, and KASP markers were also linked to these genes. These markers will be useful for the development of common bean cultivars combining the important Ur-14 and Co-3 4 /Phg-3 genes conferring resistance to three of the most destructive diseases of common bean.

Azadirachta indica (neem) leaf dietary effects on the immunity response and disease resistance of Asian seabass, Lates calcarifer challenged with Vibrio harveyi.

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Talpur, Allah Dad; Ikhwanuddin, Mhd

2013-01-01

The present study was aimed to address the possible evaluation of Azadirachta indica (neem) leaf-supplemented diets on innate immune response in Asian seabass, Lates calcarifer fingerlings against Vibrio harveyi infection. Fish were fed for two weeks diets containing six graded levels of neem leaf at 0 g, 1 g, 2 g, 3 g, 4 g and 5 g per kg feed. Fish fed neem leaf-supplemented diet displayed significant differences (p growth rate (SGR) and feed conversion ratio (FCR) compared to the control group fed without neem leaf-supplemented diet. Various innate immune parameters were examined pre-challenge and post-challenge. Fish was injected intraperitoneally with a lethal dose of V. harveyi containing 10(8) cells mL(-1). Supplementation of neem leaf diet significantly increased phagocytic activity, superoxide anion production, serum lysozyme, serum bactericidal activity, serum anti-protease activity throughout the experimental period when compared with the control group. Dietary doses of neem leaf diet significantly influenced the immune parameters, haematological parameters and blood biochemical indices of treated fish. The results suggested that fish fed neem leaf-supplemented diet improved the immune system and increased survival rate in L. calcarifer fingerlings against V. harveyi infection. Copyright © 2012 Elsevier Ltd. All rights reserved.

Maculosin, a host-specific phytotoxin for spotted knapweed from Alternaria alternata

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Stierle, Andrea C.; Cardellina, John H.; Strobel, Gary A.

1988-01-01

Several diketopiperazines have been isolated from liquid cultures of Alternaria alternata, the causal agent of black leaf blight of spotted knapweed, Centaurea maculosa Lam. One of these compounds, maculosin [the diketopiperazine cyclo(-L-Pro-L-Tyr-)], was active in the nicked-leaf bioassay at 10-5 M; synthetic maculosin possessed chemical and biological activities identical to those of the natural product. Other diketopiperazines isolated from the fungus possessed either less activity or none at all. In tests against 19 plant species, maculosin was phytotoxic only to spotted knapweed. Thus maculosin is a host-specific phytotoxin from a weed pathogen. PMID:16593989

Draft genome sequence of Cercospora sojina isolate S9, a fungus causing frogeye leaf spot (FLS disease of soybean

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Fanchang Zeng

2017-06-01

Full Text Available Fungi are the causal agents of many of the world's most serious plant diseases causing disastrous consequences for large-scale agricultural production. Pathogenicity genomic basis is complex in fungi as multicellular eukaryotic pathogens. The fungus Cercospora sojina is a plant pathogen that threatens global soybean supplies. Here, we report the genome sequence of C. sojina strain S9 and detect genome features and predicted genomic elements. The genome sequence of C. sojina is a valuable resource with potential in studying the fungal pathogenicity and soybean host resistance to frogeye leaf spot (FLS, which is caused by C. sojina. The C. sojina genome sequence has been deposited and available at DDBJ/EMBL/GenBank under the project accession number AHPQ00000000.

Generation of an infectious clone of a new Korean isolate of apple chlorotic leaf spot virus (ACLSV) driven by dual 35S and T7 promoters in a versatile binary vector

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The full-length sequence of a new isolate of Apple chlorotic leaf spot virus (ACLSV) from Korea was divergent, but most closely related to the Japanese isolate A4, at 84% nucleotide identity. The full-length cDNA of the Korean isolate of ACLSV was cloned into a binary vector downstream of the bacter...

Spilocaea pyracanthae causing leaf scab on loquat in Pakistan

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Haris Butt

2016-03-01

Full Text Available ABSTRACT Loquat is attacked by many phytopathogenic fungi. Among these Spilocaea pyracanthae is of economic importance. The fungus received no attention in Pakistan and some other parts of the world. The current study is focused on the symptomatology of this disease and the etiology of the fungus. During extensive surveys of loquat orchards in 2013 heavy infestations of this disease were observed. The leaf symptoms were observed as olive brown, opaque necrotic sub-circular spots, with light brown coloration in the center. Two or more spots coalesced in severe infections covering large leaf areas. The fungus was identified as Spilocaea pyracanthae on the basis of conidia and morphological characters. The pathogenicity of the fungus was confirmed on healthy plants under greenhouse conditions by following Koch's postulates. The fungus produced characteristic leaf scab symptoms on young leaves. This is the first report of Spilocaea pyracanthae causing leafscab of loquat in Pakistan.

Patterns of late spring frost leaf damage and recovery in a European beech (Fagus sylvatica L.) stand in south-eastern Germany based on repeated digital photographs.

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Menzel, Annette; Helm, Raimund; Zang, Christian

2015-01-01

Damage by late spring frost is a risk deciduous trees have to cope with in order to optimize the length of their growing season. The timing of spring phenological development plays a crucial role, not only at the species level, but also at the population and individual level, since fresh new leaves are especially vulnerable. For the pronounced late spring frost in May 2011 in Germany, we studied the individual leaf development of 35 deciduous trees (mainly European beech Fagus sylvatica L.) at a mountainous forest site in the Bayerischer Wald National Park using repeated digital photographs. Analyses of the time series of greenness by a novel Bayesian multiple change point approach mostly revealed five change points which almost perfectly matched the expected break points in leaf development: (i) start of the first greening between day of the year (DOY) 108-119 (mean 113), (ii) end of greening, and (iii) visible frost damage after the frost on the night of May 3rd/4th (DOY 123/124), (iv) re-sprouting 19-38 days after the frost, and (v) full maturity around DOY 178 (166-184) when all beech crowns had fully recovered. Since frost damage was nearly 100%, individual susceptibility did not depend on the timing of first spring leaf unfolding. However, we could identify significant patterns in fitness linked to an earlier start of leaf unfolding. Those individuals that had an earlier start of greening during the first flushing period had a shorter period of recovery and started the second greening earlier. Thus, phenological timing triggered the speed of recovery from such an extreme event. The maximum greenness achieved, however, did not vary with leaf unfolding dates. Two mountain ashes (Sorbus aucuparia L.) were not affected by the low temperatures of -5°C. Time series analysis of webcam pictures can thus improve process-based knowledge and provide valuable insights into the link between phenological variation, late spring frost damage, and recovery within one stand.

Characterization of apple stem grooving virus and apple chlorotic leaf spot virus identified in a crab apple tree.

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Li, Yongqiang; Deng, Congliang; Bian, Yong; Zhao, Xiaoli; Zhou, Qi

2017-04-01

Apple stem grooving virus (ASGV), apple chlorotic leaf spot virus (ACLSV), and prunus necrotic ringspot virus (PNRSV) were identified in a crab apple tree by small RNA deep sequencing. The complete genome sequence of ACLSV isolate BJ (ACLSV-BJ) was 7554 nucleotides and shared 67.0%-83.0% nucleotide sequence identity with other ACLSV isolates. A phylogenetic tree based on the complete genome sequence of all available ACLSV isolates showed that ACLSV-BJ clustered with the isolates SY01 from hawthorn, MO5 from apple, and JB, KMS and YH from pear. The complete nucleotide sequence of ASGV-BJ was 6509 nucleotides (nt) long and shared 78.2%-80.7% nucleotide sequence identity with other isolates. ASGV-BJ and the isolate ASGV_kfp clustered together in the phylogenetic tree as an independent clade. Recombination analysis showed that isolate ASGV-BJ was a naturally occurring recombinant.

Two alternative recessive quantitative trait loci influence resistance to spring black stem and leaf spot in Medicago truncatula

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Oliver Richard P

2008-03-01

Full Text Available Abstract Background Knowledge of the genetic basis of plant resistance to necrotrophic pathogens is incomplete and has been characterised in relatively few pathosystems. In this study, the cytology and genetics of resistance to spring black stem and leaf spot caused by Phoma medicaginis, an economically important necrotrophic pathogen of Medicago spp., was examined in the model legume M. truncatula. Results Macroscopically, the resistant response of accession SA27063 was characterised by small, hypersensitive-like spots following inoculation while the susceptible interaction with accessions A17 and SA3054 showed necrotic lesions and spreading chlorosis. No unique cytological differences were observed during early infection (2 populations segregating for resistance to spring black stem and leaf spot were established between SA27063 and the two susceptible accessions, A17 and SA3054. The cross between SA27063 and A17 represented a wider cross than between SA27063 and SA3054, as evidenced by higher genetic polymorphism, reduced fertility and aberrant phenotypes of F2 progeny. In the SA27063 × A17 F2 population a highly significant quantitative trait locus (QTL, LOD = 7.37; P Phoma medicaginis one (rnpm1 genetically mapped to the top arm of linkage group 4 (LG4. rnpm1 explained 33.6% of the phenotypic variance in the population's response to infection depicted on a 1–5 scale and was tightly linked to marker AW256637. A second highly significant QTL (LOD = 6.77; P rnpm2, was located on the lower arm of LG8 in the SA27063 × SA3054 map. rnpm2 explained 29.6% of the phenotypic variance and was fine mapped to a 0.8 cM interval between markers h2_16a6a and h2_21h11d. rnpm1 is tightly linked to a cluster of Toll/Interleukin1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR genes and disease resistance protein-like genes, while no resistance gene analogues (RGAs are apparent in the genomic sequence of the reference accession A17 at the

Diverse mechanisms of plant resistance to cauliflower mosaic virus revealed by leaf skeleton hybridization.

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Melcher, U; Brannan, C M; Gardner, C O; Essenberg, R C

1992-01-01

Plants not hosts for cauliflower mosaic virus (CaMV) may prevent systemic CaMV infection by interfering with dissemination of infection through the plant or by preventing viral replication and maturation. Leaf skeleton hybridization allows distinction between these two barriers. The technique assesses the spatial distribution of CaMV in an inoculated leaf by hybridization of a skeleton of the leaf with a CaMV DNA probe. Leaves or leaflets of soybean, cucumber, peanut, tomato, lettuce, spinach, pepper, onion, wheat, maize and barley, inoculated with CaMV DNA or CaMV virions were processed for leaf skeleton hybridization either immediately after inoculation or two weeks thereafter. Autoradiographic images of soybean and cucumber skeletons had many dark spots suggesting that CaMV DNA replication and local spread had occurred. Images of onion leaf skeletons prepared two weeks after inoculation with CaMV DNA had fewer spots. To test whether these spots resulted from CaMV replication, DNA was extracted from inoculated onion leaves and analyzed by electrophoresis, blotting and hybridization. Molecules recovered two weeks after inoculation resembled those inoculated, indicating absence of replication. For the other species, we found no evidence of local spread of CaMV infections. Thus, many plant species resist systemic CaMV infection by preventing replication or local spread of CaMV, while others solely prevent systemic movement of infection.

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

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LeBoldus, Jared M; Isabel, Nathalie; Floate, Kevin D; Blenis, Peter; Thomas, Barb R

2013-01-01

Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined]) zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal pathogens in plant

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

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Jared M LeBoldus

Full Text Available Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis and (or to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or hybridization ('phenological sink' hypothesis. We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined] zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal

Spotted hyena and steppe lion predation behaviours on cave bears of Europe - ?Late Quaternary cave bear extinction as result of predator stress

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Diedrich, Cajus G.

2010-05-01

Cave bears hibernated in caves all over Eurasia (e.g. Rabeder et al., 2000) including alpine regions using mainly larger caves for this purpose. Late Quaternary spotted hyenas Crocuta crocuta spelaea instead occupied mainly areas close to the cave entrances as their dens (Diedrich and Žák 2006, Diedrich 2010). The largest predator, the steppe lion Panthera leo spelaea was only a sporadic cave dweller (Diedrich 2007b, 2009b). His presence and its remains from caves all over Europe can be recently explained best as result of imported carcasses after killing by their largest antagonists, the Late Quaternary spotted hyenas. In some cases the kill might have happened in the hyena den cave itself during the theft of prey remains by lions (Diedrich 2009a). Another reason of their remains in caves of Europe is the hunting onto the herbivorous cave bears, especially during hibernation times, when megafauna prey was less available in the open environments (Diedrich 2009c). These lion remains from caves of Europe, nearly all of which were from adult animals, provide evidence of active predation by lions onto cave bears even in medium high alpine regions (Diedrich 2009b, in review). Lion skeletons in European cave bear dens were therefore often found amongst originally articulated cave bear skeletons or scattered cave bear remains and even close to their hibernation nests (Diedrich et al. 2009c, in review). Not only lions fed on cave bears documented mainly by the large quantities of chewed, punctured and crushed cave bear long-bones; even damaged skulls reveal that hyenas scavenged primarily on cave bear carcasses which were mainly responsible for the destruction of their carcasses and bones (Diedrich 2005, 2009d). Predation and scavenging on cave bears by the two largest Late Quaternary predators C. c. spelaea and P. l. spelaea explains well the large quantity of fragmented cave bear bones over all European caves in low to medium high mountainous elevations, whereas in

Genetic characterization and linkage disequilibrium mapping of resistance to gray leaf spot in maize (Zea mays L.

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Liyu Shi

2014-04-01

Full Text Available Gray leaf spot (GLS, caused by Cercospora zeae-maydis, is an important foliar disease of maize (Zea mays L. worldwide, resistance to which is controlled by multiple quantitative trait loci (QTL. To gain insights into the genetic architecture underlying the resistance to this disease, an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011. Subsequently, a genome-wide association study, using 41,101 single-nucleotide polymorphisms (SNPs, identified 51 SNPs significantly (P < 0.001 associated with GLS resistance, which could be converted into 31 QTL. In addition, three candidate genes related to plant defense were identified, including nucleotide-binding-site/leucine-rich repeat, receptor-like kinase genes similar to those involved in basal defense. Two genic SNPs, PZE-103142893 and PZE-109119001, associated with GLS resistance in chromosome bins 3.07 and 9.07, can be used for marker-assisted selection (MAS of GLS resistance. These results provide an important resource for developing molecular markers closely linked with the target trait, enhancing breeding efficiency.

Identification of Alfalfa Leaf Diseases Using Image Recognition Technology.

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Feng Qin

Full Text Available Common leaf spot (caused by Pseudopeziza medicaginis, rust (caused by Uromyces striatus, Leptosphaerulina leaf spot (caused by Leptosphaerulina briosiana and Cercospora leaf spot (caused by Cercospora medicaginis are the four common types of alfalfa leaf diseases. Timely and accurate diagnoses of these diseases are critical for disease management, alfalfa quality control and the healthy development of the alfalfa industry. In this study, the identification and diagnosis of the four types of alfalfa leaf diseases were investigated using pattern recognition algorithms based on image-processing technology. A sub-image with one or multiple typical lesions was obtained by artificial cutting from each acquired digital disease image. Then the sub-images were segmented using twelve lesion segmentation methods integrated with clustering algorithms (including K_means clustering, fuzzy C-means clustering and K_median clustering and supervised classification algorithms (including logistic regression analysis, Naive Bayes algorithm, classification and regression tree, and linear discriminant analysis. After a comprehensive comparison, the segmentation method integrating the K_median clustering algorithm and linear discriminant analysis was chosen to obtain lesion images. After the lesion segmentation using this method, a total of 129 texture, color and shape features were extracted from the lesion images. Based on the features selected using three methods (ReliefF, 1R and correlation-based feature selection, disease recognition models were built using three supervised learning methods, including the random forest, support vector machine (SVM and K-nearest neighbor methods. A comparison of the recognition results of the models was conducted. The results showed that when the ReliefF method was used for feature selection, the SVM model built with the most important 45 features (selected from a total of 129 features was the optimal model. For this SVM model, the

Identification of Alfalfa Leaf Diseases Using Image Recognition Technology

Science.gov (United States)

Qin, Feng; Liu, Dongxia; Sun, Bingda; Ruan, Liu; Ma, Zhanhong; Wang, Haiguang

2016-01-01

Common leaf spot (caused by Pseudopeziza medicaginis), rust (caused by Uromyces striatus), Leptosphaerulina leaf spot (caused by Leptosphaerulina briosiana) and Cercospora leaf spot (caused by Cercospora medicaginis) are the four common types of alfalfa leaf diseases. Timely and accurate diagnoses of these diseases are critical for disease management, alfalfa quality control and the healthy development of the alfalfa industry. In this study, the identification and diagnosis of the four types of alfalfa leaf diseases were investigated using pattern recognition algorithms based on image-processing technology. A sub-image with one or multiple typical lesions was obtained by artificial cutting from each acquired digital disease image. Then the sub-images were segmented using twelve lesion segmentation methods integrated with clustering algorithms (including K_means clustering, fuzzy C-means clustering and K_median clustering) and supervised classification algorithms (including logistic regression analysis, Naive Bayes algorithm, classification and regression tree, and linear discriminant analysis). After a comprehensive comparison, the segmentation method integrating the K_median clustering algorithm and linear discriminant analysis was chosen to obtain lesion images. After the lesion segmentation using this method, a total of 129 texture, color and shape features were extracted from the lesion images. Based on the features selected using three methods (ReliefF, 1R and correlation-based feature selection), disease recognition models were built using three supervised learning methods, including the random forest, support vector machine (SVM) and K-nearest neighbor methods. A comparison of the recognition results of the models was conducted. The results showed that when the ReliefF method was used for feature selection, the SVM model built with the most important 45 features (selected from a total of 129 features) was the optimal model. For this SVM model, the

Evaluation of banana hybrids for tolerance to black leaf streak (Mycosphaerella fijiensis Morelet) in Puerto Rico

Science.gov (United States)

In Puerto Rico, bananas (including plantains) are important agricultural commodities; their combined production totaled 133,500 tons in 2008. Black leaf streak (BLS) and Sigatoka leaf spot diseases, caused by Mycosphaerella fijiensis and M. musicola, respectively, are responsible for significant los...

[Fatty acid variation in yellowfin tuna, spotted weakfish and Florida pompano when submitted to six cooking techniques].

Science.gov (United States)

Castro-González, María Isabel; Maafs-Rodríguez, Ana Gabriela; Romo Pérez-Gil, Fernando

2013-03-01

The aim of the present study was to analyze the effect of six cooking techniques (steamed, foiled, foiled with banana leaf, baked, microwave-cooked and light frying) in the fatty acid content of Thunnus albacore (yellowfin tuna), Cynoscionnebulosus (spotted weakfish) and Trachinotuscarolinus (Florida pompano). After cooking the fish fillets, fatty acid analyses were performed using gas chromatography. Total lipids increased in all cooking techniques in tunaand spotted weakfish. Saturated fatty acids of tuna and spotted weakfish increased in three cooking techniques, while in Florida pompano only gas oven raised their content. Lightly frying generated the highest content of n-3 in tuna and spotted weakfish, and the lowest in Florida pompano, specie that presented less variation. In tuna fish, the most recommended cooking techniques are foiled with aluminum and microwave oven; for spotted weakfish, foiled with banana leaf; while Florida pompano can be prepared using all cooking methods except gas oven. This information is useful to enrich data from chemical composition tables, in which concentrations are usually presented in raw food.

Separation and identification of Musa acuminate Colla (banana) leaf proteins by two-dimensional gel electrophoresis and mass spectrometry.

Science.gov (United States)

Lu, Y; Qi, Y X; Zhang, H; Zhang, H Q; Pu, J J; Xie, Y X

2013-12-19

To establish a proteomic reference map of Musa acuminate Colla (banana) leaf, we separated and identified leaf proteins using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Tryptic digests of 44 spots were subjected to peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS. Three spots that were not identified by MALDI-TOF MS analysis were identified by searching against the NCBInr, SwissProt, and expressed sequence tag (EST) databases. We identified 41 unique proteins. The majority of the identified leaf proteins were found to be involved in energy metabolism. The results indicate that 2D-PAGE is a sensitive and powerful technique for the separation and identification of Musa leaf proteins. A summary of the identified proteins and their putative functions is discussed.

The taphonomy of a remarkable leaf bed assemblage from the Late Oligocene-Early Miocene Gore Lignite Measures, southern New Zealand

Energy Technology Data Exchange (ETDEWEB)

Ferguson, David K.; Zetter, Reinhard; Vavra, Norbert [Department of Paleontology, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria); Lee, Daphne E. [Department of Geology, University of Otago, PO Box 56, Dunedin (New Zealand); Bannister, Jennifer M. [Department of Botany, University of Otago, PO Box 56, Dunedin (New Zealand); Jordan, Gregory J. [School of Plant Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001 (Australia); Mildenhall, Dallas C. [GNS Science, PO Box 30-368, Lower Hutt (New Zealand)

2010-08-01

A diverse assemblage of fossil leaves showing cellular detail is reported from the Late Oligocene-Early Miocene Gore Lignite Measures, southern New Zealand. The leaf-remains include at least five conifers, such as the genera Agathis, Dacrycarpus, Phyllocladus and Dacrydium, as well as a number of angiosperms including Gymnostoma, Nothofagus Subgenus Brassospora, Phormium, Proteaceae, Sapindaceae and Ericaceae. A parallel palynological study has identified a number of the same elements. The leaf layers represent litter horizons laid down in pools on the surface of a subtropical ombrotrophic forest mire that formed on an extensive low-lying coastal plain. Highly acidic water ponded in tree-fall depressions prevented microbial decay of the foliage. Taxa represented by both leaves and pollen are considered to have been components of the autochthonous swamp forest. Some other pollen grains are thought to represent local elements, based on the pollination biology of their nearest living relatives. Other taxa whose extant representatives are wind-pollinated may have grown further away. (author)

Identification of two new races of Diplocarpon rosae Wolf, the causal agent of rose black spot disease

Science.gov (United States)

The fungal pathogen, Diplocarpon rosae Wolf, infects only roses (Rosa spp.) and leads to rose black spot disease. Rose black spot is the most problematic disease of outdoor grown roses worldwide, due to the potential for rapid leaf yellowing and defoliation. Plants repeatedly defoliated from black ...

Occurrence of Target Spot on Rosemary Caused by Corynespora cassiicola in Korea

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Wang-Hyu Lee

2013-03-01

Full Text Available The purpose of this experiment was to investigate the development of new spot disease on the leaf and stem of rosemary (Rosmarinus officinalis in commercial greenhouses at Jeonju and Namwon in Korea. Incidence of target spot on rosemary was higher at the end of the rainy season with high humidity. Those symptoms were black ring spots (3−5 mm in diameter and withering on green leaves and stems. Conidiophores and conidia were formed on the infected tissue in moist chamber and conidia were shown as the cylindrical and oval types in chain, ranged from 55 to 275 μm in length, and 7 to 14 μm in width. Conidia with eight to ten pseudosepta were formed on the conidiapore. The optimum growth temperature of isolates was 30oC on the PDA medium under the dark condition. In the pathogenesis test, the target spot and withering symptoms were appeared on the leaves and stems 3 days after inoculation showing similar symptoms compared to those of in nature. The same fungus was re-isolated from infected lesion, indicating that Corynespora cassiicola caused leaf target spot and twig blight on rosemary. The rDNA ITS nucleotide sequences of the pure cultured isolate from the diseased area on rosemary showed 100% similarity to the sequences of C. cassiicola available in the GenBank database (JQ595296, JQ595297, FJ852715 and AY238606. Therefore, we report that the target spot of leaves and stems in rosemary was caused by C. cassiicola.

Determination of Economic Control Thresholds for Bacterial Spot on Red Pepper Caused by Xanthomonas campestris pv. vesicatoria

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Ju-Hee Kim

2015-06-01

Full Text Available This study was carried out to develop the economic thresholds for the control of bacterial spot of red pepper. The correlation between diseased leaf rate and yield in field was Y = -0.724X + 281.58, R² = 0.78, r = -0.88**. The correlation between diseased leaf rate and yield loss in field was Y = 0.813X + 15.95, R² = 0.78, r = 0.88*. We found that control thresholds was below 30.3% diseased leaves rate per plant in field. The economic control thresholds for bacterial spot of red pepper was below 16.3%.

Production of Gentisyl Alcohol from Phoma herbarum Endophytic in Curcuma longa L. and Its Antagonistic Activity Towards Leaf Spot Pathogen Colletotrichum gloeosporioides.

Science.gov (United States)

Gupta, Suruchi; Kaul, Sanjana; Singh, Baljinder; Vishwakarma, Ram A; Dhar, Manoj K

2016-11-01

Endophytes from medicinal plants represent a potential source of bioactive compounds. During the present investigation, fungal endophytes were isolated from turmeric (Curcuma longa), an important medicinal plant. A total of 207 endophytic fungal isolates were obtained from the rhizome of C. longa L. They were grouped into seven genera based on morphological and molecular data. The fungal endophytes of C. longa were evaluated for antifungal activity against Colletotrichum gloeosporioides, the causal organism of leaf spot of turmeric. The disease is a major cause for economic loss in turmeric cultivation. Endophytic Phoma herbarum showed significant activity against C. gloeosporioides and was therefore selected for further studies. A compound gentisyl alcohol was isolated from P. herbarum which showed effective antagonism against C. gloeosporioides. The organism could therefore be used as a biocontrol agent against C. gloeosporioides.

Remote sensing based mapping of leaf nitrogen and leaf area index in European landscapes using the REGularized canopy reFLECtance (REGFLEC) model

DEFF Research Database (Denmark)

Boegh, E.; Houborg, R.; Bienkowski, J.

2011-01-01

index (LAI) are important determinants of the maximum CO2 Methods/Approach uptake by plants and trees. In the EU project NitroEurope, high spatial resolution (10-20 m) remote sensing data from the HRG and HRVIR sensors onboard the SPOT satellites were acquired to derive maps of leaf N and LAI for 5...... European landscapes. The estimations of leaf N, Cab and LAI soil reflectance parameters and canopy parameters are discussed in relation to the prevailing soil types and vegetation characteristics of land cover classes across the 5 European landscapes....

Different waves of effector genes with contrasted genomic location are expressed by Leptosphaeria maculans during cotyledon and stem colonization

OpenAIRE

Gervais, Julie; Rouxel, Thierry; Fudal, Isabelle; Balesdent, Marie-Helene

2016-01-01

Leptosphaeria maculans, causal agent of blackleg disease, colonizes oilseed rape (Brassica napus) in two stages: a short and early colonization stage corresponding to cotyledon and leaf colonization leading to leaf spots development, and a late colonization stage during which the fungus colonizes systemically and symptomlessly the plant during several months before stem canker appears. To date, determinants of late colonization stage are poorly understood. Here, we hypothesized that L. macula...

Encountering epidemic effects of leaf spot disease (Alternaria brassicae) on Aloe vera by fungal biocontrol agents in agrifields-An ecofriendly approach.

Science.gov (United States)

Ghosh, Swapan Kumar; Banerjee, Subhankar; Pal, Sujoy; Chakraborty, Niloy

2018-01-01

Aloe vera (L.) Burm.f. is a highly important and extensively cultivated medicinal plant and that is also extensively used in the cosmetic industry. It has been frequently reported to suffer from Alternaria leaf spot disease in various parts of the world. Various fungicides used to combat this disease, have deleterious effects on the environment and on pharmacologically important constituents of Aloe vera. To avoid the harmful effects of fungicides an ecofriendly approach has been adopted here. A weekly survey was conducted during 2013-2015 in and around North 24 Parganas (West Bengal) to obtain the percentage of disease index (PDI). For biological control of the disease, screening of the antagonistic efficacy of biocontrol agents was carried out through the in vitro dual-culture-plate method and scanning electron microscopy (SEM) was used to study the mechanism. The in vitro effects of fungicides on the radial growth of the pathogen were evaluated through the poison food method and were compared with potent antagonistic fungi. Field application of potent antagonistic fungi was conducted through the dip-and-spray method. The results showed that, the PDI peaked during the hot and humid conditions of May to September (76.57%-98.57%) but decreased during the winter, December-January (35.71-46.66%). Trichoderma asperellum exerted the greatest inhibition of the radial growth of A. brassicae acting through non volatile (70.39%) and volatile metabolites (72.17%). A SEM study confirmed the hyperparasitic nature of T. asperellum through hyphal coiling-T. asperellum was similar to 2% blitox-50 (73.92%) and better than 2% bavistin (59.77%) (in vitro). In agricultural field trials (2013-15), Trichoderma application restricted the disease to the smallest area (PDI 24.00-29.33%) in comparison to untreated plots (73.33%). In conclusion, saplings treated with the dip method (108 spores / mL) and sprayed 4 times with a spore suspension of biocontrol agents such as T. asperellum, T

Protein profile of Beta vulgaris leaf apoplastic fluid and changes induced by Fe deficiency and Fe resupply

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Laura eCeballos-Laita

2015-03-01

Full Text Available The fluid collected by direct leaf centrifugation has been used to study the proteome of the sugar beet apoplastic fluid as well as the changes induced by Fe deficiency and Fe resupply to Fe-deficient plants in the protein profile. Plants were grown in Fe-sufficient and Fe-deficient conditions, and Fe resupply was carried out with 45 μM Fe(III-EDTA for 24 h. Protein extracts of leaf apoplastic fluid were analyzed by two-dimensional isoelectric focusing-SDS-PAGE electrophoresis. Gel image analysis revealed 203 consistent spots, and proteins in 81% of them (164 were identified by nLC-MS/MS using a custom made reference repository of beet protein sequences. When redundant UniProt entries were deleted, a non-redundant leaf apoplastic proteome consisting of 109 proteins was obtained. TargetP and SecretomeP algorithms predicted that 63% of them were secretory proteins. Functional classification of the non-redundant proteins indicated that stress and defense, protein metabolism, cell wall and C metabolism accounted for approximately 75% of the identified proteome. The effects of Fe-deficiency on the leaf apoplast proteome were limited, with only five spots (2.5% changing in relative abundance, thus suggesting that protein homeostasis in the leaf apoplast fluid is well maintained upon Fe shortage. The identification of three chitinase isoforms among proteins increasing in relative abundance with Fe-deficiency suggests that one of the few effects of Fe deficiency in the leaf apoplast proteome includes cell wall modifications. Iron resupply to Fe deficient plants changed the relative abundance of 16 spots when compared to either Fe-sufficient or Fe-deficient samples. Proteins identified in these spots can be broadly classified as those responding to Fe-resupply, which included defense and cell wall related proteins, and non-responsive, which are mainly protein metabolism related proteins and whose changes in relative abundance followed the same trend as

Reproductive ecology of Commerson's leaf-nosed bats ...

African Journals Online (AJOL)

Reproductive ecology of Commerson's leaf-nosed bats Hipposideros commersoni ... Reproductive females dispersed twice during the annual cycle, while in ... Synchronized parturitions within maternity roosts (in late October) created a hot, ...

Escala diagramática para avaliação da severidade da cercosporiose em caupi Diagrammatic scale for assessment of Cercospora leaf spot severity in cowpea

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Igor Corrêa Lima Albert

2008-10-01

Full Text Available A cercosporiose, causada por Cercospora cannescens e Pseudocercospora cruenta, é uma importante doença do caupi (Vigna unguiculata no Brasil. Devido à inexistência de métodos padronizados para quantificação dessa doença, foi desenvolvida uma escala diagramática com níveis de 1, 2, 4, 8, 16, 32, 64 e 82% de área foliar lesionada. A escala diagramática foi validada por 10 avaliadores, usando 50 folíolos de caupi com diferentes níveis de severidade, mensurados previamente com o programa Assess®. A acurácia, a precisão e a reprodutibilidade das estimativas de cada avaliador foi determinada por regressão linear simples entre a severidade real e a estimada, com e sem o auxílio da escala. Com a escala, os avaliadores obtiveram melhores níveis de acurácia e precisão das estimativas, com os erros absolutos concentrando-se na faixa de 10%. Os avaliadores apresentaram elevada repetibilidade (94% e reprodutibilidade (90% em 82,3% dos casos das estimativas com a utilização da escala. Portanto, a escala diagramática proposta é adequada para avaliação da severidade da cercosporiose do caupi.Cercospora leaf spot caused by Cercospora canescens and Pseudocercospora cruenta is an important disease of cowpea (Vigna unguiculata in Brazil. Due to the inexistence of standard methods for the assessment of this disease, a diagrammatic scale was developed with 1, 2, 4, 8, 16, 32, 64 and 82% of diseased leaf area. The diagrammatic scale was validated by 10 raters using 50 cowpea leaflets with different levels of severity previously measured by the software Assess®. The accuracy, precision and reproducibility of the estimative of each rater were determined by simple linear regression between actual and estimated severity, with and without the use of the scale. With the scale raters obtained better levels of accuracy and precision, with absolute errors concentrating around 10%. Raters showed high repeatability (94% and reproducibility ( 90% in

Contribution of the drought tolerance-related Stress-responsive NAC1 transcription factor to resistance of barley to Ramularia leaf spot

Science.gov (United States)

MCGRANN, GRAHAM R D; STEED, ANDREW; BURT, CHRISTOPHER; GODDARD, RACHEL; LACHAUX, CLEA; BANSAL, ANURADHA; CORBITT, MARGARET; GORNIAK, KALINA; NICHOLSON, PAUL; BROWN, JAMES K M

2015-01-01

NAC proteins are plant transcription factors that are involved in tolerance to abiotic and biotic stresses, as well as in many developmental processes. Stress-responsive NAC1 (SNAC1) transcription factor is involved in drought tolerance in barley and rice, but has not been shown previously to have a role in disease resistance. Transgenic over-expression of HvSNAC1 in barley cv. Golden Promise reduced the severity of Ramularia leaf spot (RLS), caused by the fungus Ramularia collo-cygni, but had no effect on disease symptoms caused by Fusarium culmorum, Oculimacula yallundae (eyespot), Blumeria graminis f. sp. hordei (powdery mildew) or Magnaporthe oryzae (blast). The HvSNAC1 transcript was weakly induced in the RLS-susceptible cv. Golden Promise during the latter stages of R. collo-cygni symptom development when infected leaves were senescing. Potential mechanisms controlling HvSNAC1-mediated resistance to RLS were investigated. Gene expression analysis revealed no difference in the constitutive levels of antioxidant transcripts in either of the over-expression lines compared with cv. Golden Promise, nor was any difference in stomatal conductance or sensitivity to reactive oxygen species-induced cell death observed. Over-expression of HvSNAC1 delayed dark-induced leaf senescence. It is proposed that mechanisms controlled by HvSNAC1 that are involved in tolerance to abiotic stress and that inhibit senescence also confer resistance to R. collo-cygni and suppress RLS symptoms. This provides further evidence for an association between abiotic stress and senescence in barley and the development of RLS. PMID:25040333

Magnetic fields in starspots on late-type giants

International Nuclear Information System (INIS)

Jahn, K.

1985-01-01

Computations of models of magnetic starspots on cool active giants show that the value of the magnetic intensity in spots is generally of the order of one kilogauss, although in larger spots the field can be as weak as a few hundred gauss. It is also argued, that spots on giants qualitatively differ from those on late-type dwarfs, since they cannot be too large. The largest individual spots can cover at most about one percent of a stellar hemisphere. This is in a very good agreement with earlier suggestions based on observations of spotted giants. The assumption that spots are the regions of the strongest magnetic field allows to discuss recent attempts of detection of the magnetic field on late-type giants. Polarimetric measurements most probably cannot be successful, due to a small field strength and a complex topology of the field. It is shown that even if a whole surface was covered by spots with relatively strong field, the resulting not longitudinal field would be as weak as a few gauss. Also methods independent of polarimetric measurements, based on the analysis of Zeeman broadening, generally are not sensitive enough to detect the magnetic field on giants, even in spots. λ And is discussed as an example. The comparison of models of spots computed for that stars with photometric observations suggests, that a dark region on λ And consists of hundreds of small spots (each of them smaller than about 0.1% of the hemisphere), in which the magnetic intensity cannot exceed about 900 gauss, and most probably is even smaller. 23 refs., 4 figs., 4 tabs. (author)

Antifungal Potential of Indigenous Medicinal Plants against Myrothecium Leaf Spot of Bitter Gourd ( Momordica charantia L.

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Muhammad Abid

2017-08-01

Full Text Available ABSTRACT Bitter gourd is of great importance due to its usage against the treatment of numerous ailments in human beings. A comprehensive survey at four localities of Southern Punjab, Pakistan was carried out to determine the severity of Myrothecium leaf spot. Maximum disease severity was at C1 (Chak 11/NP and least at C2 (Kot Mehtab. Among isolated species Myrothecium roridum was found more prevalent and pathogenic as compared to M. verrucaria. Antifungal activity using solvent extracts of five medicinal plants (Mangifera indica, Melia azedarach, Nicotiana tabacum, Moringa oleifera and Eucalyptus globosum were evaluated against isolated species by agar well diffusion method at various concentrations (0.01, 0.10, 1.0 and 10.0 µg / mL. N. tabacum revealed maximum zone size (13.40 mm and 8.28 mm with ethanol and chloroform solvents respectively followed by M. azedarach (9.00mm and 6.48mm. However, least inhibition was observed with ethanol and chloroform extracts of E. globosum (6.04mm and 3.88mm zone size respectively. Ethanol extracts showed highest activity when compared to chloroform extracts. Qualitative phytochemical analysis showed that all the selected plants are rich in chemical compounds such as alkaloids, terpenoids, flavonoids and phenols whereas Saponins was only present in N. tabacum while absent in rest of the extracts.

Narrow sense heritability and gene effects for late leaf spot ...

African Journals Online (AJOL)

SM 03590, Valencia C × ICGV-SM 02501 and NuMex-M3 × ICGV-SM 02501 crosses, respectively. Both additive and dominance gene effects contributed significantly to the inheritance of LLS resistance in all the crosses, except in Redbeauty ...

narrow sense heritability and gene effects for late leaf spot

African Journals Online (AJOL)

ACSS

(33-55%) and protein (19- 31%) (Jambunathan,. 1991; Shilpa et ... information on non-allelic interactions for LLS resistance in ..... molecular breeding for rust resistance in groundnut ... Comperative simulation studies on the effect of selection.

Physico-chemical characterization of banana varieties resistant to black leaf streak disease for industrial purposes

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Rossana Catie Bueno de Godoy

2016-01-01

Full Text Available ABSTRACT: Cultivated bananas have very low genetic diversity making them vulnerable to diseases such as black-Sigatoka leaf spot. However, the decision to adopt a new banana variety needs to be based on a robust evaluation of agronomical and physical-chemical characteristics. Here, we characterize new banana varieties resistant to black-Sigatoka leaf spot and compare them to the most widely used traditional variety (Grand Naine. Each variety was evaluated for a range of physic-chemical attributes associated with industrial processing and flavor: pH, TTA, TSS/TTA, total sugars, reducing sugars and non-reducing sugars, humidity, total solids and yield. The Thap Maeo variety had the highest potential as a substitute for the Grand Naine variety, having higher levels of total soluble solids, reducing sugars, total sugars and humidity. The Caipira and FHIA 2 varieties also performed well in comparison with the Grand Naine variety. Cluster analysis indicated that the Grand Naine variety was closely associated with varieties from the Gross Michel subgroup (Bucaneiro, Ambrosia and Calipso and the Caipira variety, all of which come from the same AAA genomic group. It was concluded that several of the new resistant varieties could potentially substitute the traditional variety in areas affected by black-Sigatoka leaf spot disease.

Effect of foliar fertilizer and fungicidal protection against leaf spot diseases on winter wheat

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Agnieszka Mączyńska

2012-12-01

Full Text Available Field experiments were carried out in the seasons 2000/2001 and 2001/2002 in Plant Protection Institute, Sooenicowice Branch to assess the influence of foliar fertilizers such as Ekolist PK 1, Ekolist Mg, Mikrosol Z and Urea on healthiness of winter wheat. Foliar fertilizers were mixed with fungicides. The fungicides were applied at full or half recommended doses. The effect of the disease on wheat leaves was evaluated three times in each vegetation season. Remaining green leaf area (GLA of leaves was also determined. GLA of the leaves F-1 was not significantly different for each combination with different fertilization and different levels of chemical treatment. The application of foliar fertilizer only had no effect on green leaf area (GLA. The results indicate that foliar fertilization of all experimental plots improved leaf condition and therefore halted the development of wheat leaf diseases. The increases of 1000 grain mass and yield was high for each plot where a fertilizer and a full or half dose of a fungicide was applied. Foliar fertilizing with no chemical control had no proven effect on studied parameters.

Resistance to gray leaf spot of maize: genetic architecture and mechanisms elucidated through nested association mapping and near-isogenic line analysis.

Science.gov (United States)

Benson, Jacqueline M; Poland, Jesse A; Benson, Brent M; Stromberg, Erik L; Nelson, Rebecca J

2015-03-01

Gray leaf spot (GLS), caused by Cercospora zeae-maydis and Cercospora zeina, is one of the most important diseases of maize worldwide. The pathogen has a necrotrophic lifestyle and no major genes are known for GLS. Quantitative resistance, although poorly understood, is important for GLS management. We used genetic mapping to refine understanding of the genetic architecture of GLS resistance and to develop hypotheses regarding the mechanisms underlying quantitative disease resistance (QDR) loci. Nested association mapping (NAM) was used to identify 16 quantitative trait loci (QTL) for QDR to GLS, including seven novel QTL, each of which demonstrated allelic series with significant effects above and below the magnitude of the B73 reference allele. Alleles at three QTL, qGLS1.04, qGLS2.09, and qGLS4.05, conferred disease reductions of greater than 10%. Interactions between loci were detected for three pairs of loci, including an interaction between iqGLS4.05 and qGLS7.03. Near-isogenic lines (NILs) were developed to confirm and fine-map three of the 16 QTL, and to develop hypotheses regarding mechanisms of resistance. qGLS1.04 was fine-mapped from an interval of 27.0 Mb to two intervals of 6.5 Mb and 5.2 Mb, consistent with the hypothesis that multiple genes underlie highly significant QTL identified by NAM. qGLS2.09, which was also associated with maturity (days to anthesis) and with resistance to southern leaf blight, was narrowed to a 4-Mb interval. The distance between major leaf veins was strongly associated with resistance to GLS at qGLS4.05. NILs for qGLS1.04 were treated with the C. zeae-maydis toxin cercosporin to test the role of host-specific toxin in QDR. Cercosporin exposure increased expression of a putative flavin-monooxygenase (FMO) gene, a candidate detoxification-related gene underlying qGLS1.04. This integrated approach to confirming QTL and characterizing the potential underlying mechanisms advances the understanding of QDR and will facilitate the

Resistance to gray leaf spot of maize: genetic architecture and mechanisms elucidated through nested association mapping and near-isogenic line analysis.

Directory of Open Access Journals (Sweden)

Jacqueline M Benson

2015-03-01

Full Text Available Gray leaf spot (GLS, caused by Cercospora zeae-maydis and Cercospora zeina, is one of the most important diseases of maize worldwide. The pathogen has a necrotrophic lifestyle and no major genes are known for GLS. Quantitative resistance, although poorly understood, is important for GLS management. We used genetic mapping to refine understanding of the genetic architecture of GLS resistance and to develop hypotheses regarding the mechanisms underlying quantitative disease resistance (QDR loci. Nested association mapping (NAM was used to identify 16 quantitative trait loci (QTL for QDR to GLS, including seven novel QTL, each of which demonstrated allelic series with significant effects above and below the magnitude of the B73 reference allele. Alleles at three QTL, qGLS1.04, qGLS2.09, and qGLS4.05, conferred disease reductions of greater than 10%. Interactions between loci were detected for three pairs of loci, including an interaction between iqGLS4.05 and qGLS7.03. Near-isogenic lines (NILs were developed to confirm and fine-map three of the 16 QTL, and to develop hypotheses regarding mechanisms of resistance. qGLS1.04 was fine-mapped from an interval of 27.0 Mb to two intervals of 6.5 Mb and 5.2 Mb, consistent with the hypothesis that multiple genes underlie highly significant QTL identified by NAM. qGLS2.09, which was also associated with maturity (days to anthesis and with resistance to southern leaf blight, was narrowed to a 4-Mb interval. The distance between major leaf veins was strongly associated with resistance to GLS at qGLS4.05. NILs for qGLS1.04 were treated with the C. zeae-maydis toxin cercosporin to test the role of host-specific toxin in QDR. Cercosporin exposure increased expression of a putative flavin-monooxygenase (FMO gene, a candidate detoxification-related gene underlying qGLS1.04. This integrated approach to confirming QTL and characterizing the potential underlying mechanisms advances the understanding of QDR and will

Fungicide efficacy in peach rusty spot control in Serbia

OpenAIRE

Dolovac Nenad; Miletić Novica; Aleksić Goran; Savić Dušan; Živković Svetlana; Trkulja Nenad; Bulajić Aleksandra

2010-01-01

Rusty Spot has long been known as a harmful peach disease in many parts of the world. During the past several years, rusty spot infection of the late-maturing peach cultivars (Summerset, Suncrest, Fayette and O’Henry) caused significant yield losses in Serbia. Although the etiology of the disease is still unknown, there are numerous studies attempting to set a strategy for its control and recommend appropriate chemical and other peach protection methods. Ho...

Some new and noteworthy diseases of poplars in India. [Botryodiplodia sett-rot; Alternaria tip blight; Cladosporium leaf spot; Fusarium pink incrustation

Energy Technology Data Exchange (ETDEWEB)

Singh, S.

1983-09-01

Four new diseases of poplars namely Botryodiplodia sett-rott, Alternaria tip blight, Cladosporium leaf spot and Fusarium pink incrustation are described in this paper. Botryodiplodia palmarum causes sett-rott of poplars both at pre-sprouting and post-sprouting stage. The pathogen also causes mortality of poplar plants in the field within 4-6 weeks after planting. Alternaria stage of Pleuspora infectoria has been found as the cause of blackening and dying of growing tips and young leaves of a Populus sp. and P. deltoides in nurseries. Cladosporium humile has been recorded as the cause of brown spot followed by crumpling and premature shedding of leaves in P. ciliata, P. nigra and P. alba. The cause of Fusarium incrustation disease on P. cilata has been identified as Fusarium sp. of Gibbosum group. Pathogenicity of Botryodiplodia palmarum and Alternaria stage of Pleospora infectoria was confirmed by artificial inoculations. Brief descriptions of Alternaria, Cladosporium and Fusarium are also given. The paper also gives a short account of some noteworthy diseases recorded on poplars namely Ganoderma root rot, foliage ruts and stem cankers. Ganoderma root-rot is found to reach alarming proportions in closely spaced poplar plantations. Melampsora ciliata, an indigenous rust, is found to attack mainly clones of P. deltoides, P. yunnanensis, P. trichocarpa, P. alba and some cultivars of P. x euramericana in nurseries. A brief account of three types of stem cankers i.e. cankers due to pink disease fungus, Corticium salmonicolor, sun-scaled cankers and cankers associated with slime flux on various clones of P. deltoides is also given.

The development of a dense SNP-based consensus map and QTL detection for black spot resistance in five diploid rose populations [abstract

Science.gov (United States)

Black spot (BS) disease (Diplocarpon rosae (Lib.) Wolf) of rose is the most important leaf disease of garden roses in warm humid areas. Although the partial (horizontal) resistance to black spot has been shown to be moderately heritable, the responsible quantitative trait loci (QTL) remain unidentif...

Demography of Northern Spotted Owls in southwestern Oregon

Science.gov (United States)

Zabel, Cynthia J.; Salmons, Susan E.; Forsman, Eric D.; DeStefano, Stephen; Raphael, Martin G.; Gutierrez, R.J.

1996-01-01

Northern Spotted Owls (Strix occidentalis caurina) are associated with lower elevation, commercially valuable, late-successional coniferous forests in the Pacific Northwest. Meta-analyses of demographic parameters indicate that Northern Spotted Owl populations are declining throughout their range (Anderson and Burnham 1992, Burnham et al. this volume). Recent research has attempted to determine whether management activities have affected the viability of Spotted Owl populations, and results have led to development of conservation plans for the species (Dawson et al. 1987, Thomas et al. 1990, Murphy and Noon 1992, USDI 1992, Thomas et al. 1993b).In the Recovery Plan for the Northern Spotted Owl (USDI 1992b) threats to the species were identified as small population sizes, declining populations, limited amounts of habitat, continued loss and fragmentation of habitat, geographically isolated populations, and predation and competition from other avian species. Weather and fire are natural processes that also may affect reproductive success of Spotted Owls. Weather may be a factor in the high annual variability in fecundity of Spotted Owls, as has been suggested for other predatory bird species (Newton, 1979, 1986). However, these factors have not been addressed in previous studies of Spotted Owls.Our objectives were to estimate survival, fecundity, and annual rates of population change (l) for resident, territorial female Spotted Owls at two study areas in the coastal mountains of southwestern Oregon. We tested if the amount of rainfall was correlated with reproduction of Spotted Owls. While surveying for Spotted Owls, we documented the increased presence of Barred Owls (Strix varia), a potential competitor of Spotted Owls.

Fungitoxicidade de grupos químicos sobre Myrothecium roridum in vitro e sobre a mancha-de-mirotécio em algodoeiro Fungitoxicity of chemical groups on Myrothecium roridum in vitro and on myrothecium leaf spot on cotton plants

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Juliano César da Silva

2006-05-01

Full Text Available O objetivo deste trabalho foi avaliar a fungitoxicidade de produtos pertencentes aos grupos dos benzimidazóis, triazóis, estrobilurinas, isoftalonitrilas e ditiocarbamatos sobre a germinação conidial e o crescimento micelial in vitro de isolados de Myrothecium roridum e, in vivo, sobre a severidade da mancha-de-mirotécio em plantas de algodoeiro. Nos testes in vitro os fungicidas foram solubilizados em meio BDA, utilizando-se as concentrações de 0,1, 1, 10 e 100 mg L-1 de ingrediente ativo. A fungitoxidade dos produtos foi avaliada por meio da ED50 (dose necessária para inibir 50% da germinação conidial ou crescimento micelial. Em casa de vegetação, estimou-se a severidade da mancha-de-mirotécio pela porcentagem de área foliar lesionada nas plantas de algodoeiro tratadas antes (preventivo e depois (curativo da inoculação do patógeno. Os fungicidas tiofanato metílico, carbendazim, metconazol, tiofanato metílico + clorotalonil, piraclostrobina + epoxiconazol, piraclostrobina + metiram, triflostrobina + propiconazol e tebuconazol inibiram com alta eficácia (ED50The objective of this work was to evaluate the toxicity of benzimidazoles, triazoles, strobilurins, isoftalonitrils and ditiocarbamats on Myrothecium roridum conidial germination and micelial growth in vitro, and the myrothecium leaf spot severity on cotton plants. On in vitro tests, fungicides were solubilized in PDA media at the following concentrations: 0.1, 1, 10 and 100 mg L-1. The toxicity of the products were evaluated by the ED50 rate (required for inhibiting 50% of the conidial germination or mycelial growth. In greenhouse tests, the severity of myrothecium leaf spot was quantified by measuring the leaf area affected by the pathogen in cotton plants sprayed before (preventive and after (curative the pathogen inoculation. The fungicides thiophanate methyl, carbendazim, metconazole, thiophanate methyl + chlorothalonil, pyraclostrobin + epoxyconazole, pyraclostrobin

Identification of Causes of Red Leaf Spot on Red Jabon (Anthocephalus macrophyllus (Roxb. Havil Seeds in Kima Atas Permanent Nursery, Manado Forestry Research Institute (Identifikasi Penyebab Penyakit Bercak Merah Pada Bibit Jabon Merah (Anthocephalus Macrophyllus (Roxb. Havil di Persemaian Permanen Kima Atas, Balai Penelitian Kehutanan Manado

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Hanif Nurul Hidayah

2015-12-01

Full Text Available Fulfillment the needs of Red Jabon (Anthocephalus macrophyllus (Roxb. Havil seeds on the other hand can create an unbalanced ecosystem. The availability of red Jabon seed was becoming a source of food for pests, then it causes an explosion of pests and pathogens. The disease that most often affect red Jabon seeds, both in the nursery and in the field was red leaf spot (antraknose. The initial step to control red leaf spot disease is the identification of causing. Identification method performed by observation of the symptoms in the field, followed by microscopic observation in a laboratory. Based on the identification result, it was known that the disease caused by the fungus Cercospora sp., Colletotrichum sp. and Pestalotia sp. The effect caused by those fungal pathogens was the disruption of the photosynthetic process that ultimately inhibits the growth of red Jabon seeds. The controls which have been done are arranged the watering intensity, isolated the infected seed,and  applied the chemical fungicide.

Progressive outer retinal necrosis presenting as cherry red spot.

Science.gov (United States)

Yiu, Glenn; Young, Lucy H

2012-10-01

To report a case of progressive outer retinal necrosis (PORN) presenting as a cherry red spot. Case report. A 53-year-old woman with recently diagnosed HIV and varicella-zoster virus (VZV) aseptic meningitis developed rapid sequential vision loss in both eyes over 2 months. Her exam showed a "cherry red spot" in both maculae with peripheral atrophy and pigmentary changes, consistent with PORN. Due to her late presentation and the rapid progression of her condition, she quickly developed end-stage vision loss in both eyes. PORN should be considered within the differential diagnosis of a "cherry red spot." Immune-deficient patients with a history of herpetic infection who present with visual loss warrant prompt ophthalmological evaluation.

Foliar Application of the Fungicide Pyraclostrobin Reduced Bacterial Spot Disease of Pepper

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Beom Ryong Kang

2018-03-01

Full Text Available Pyraclostrobin is a broad-spectrum fungicide that inhibits mitochondrial respiration. However, it may also induce systemic resistance effective against bacterial and viral diseases. In this study, we evaluated whether pyraclostrobin enhanced resistance against the bacterial spot pathogen, Xanthomonas euvesicatora on pepper (Capsicum annuum. Although pyraclostrobin alone did not suppressed the in vitro growth of X. euvesicatoria, disease severity in pepper was significantly lower by 69% after treatments with pyraclostrobin alone. A combination of pyraclostrobin with streptomycin reduced disease by over 90% that of the control plants. The preventive control of the pyraclostrobin against bacterial spot was required application 1-3 days before pathogen inoculation. Our findings suggest that the fungicide pyraclostrobin can be used with a chemical pesticide to control bacterial leaf spot diseases in pepper.

NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

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Yasuyo Sekiyama

2017-01-01

Full Text Available Cercospora leaf spot (CLS is one of the most serious leaf diseases for sugar beet (Beta vulgaris L. worldwide. The breeding of sugar beet cultivars with both high CLS resistance and high yield is a major challenge for breeders. In this study, we report the nuclear magnetic resonance (NMR-based metabolic profiling of field-grown leaves for a subset of sugar beet genotypes harbouring different levels of CLS resistance. Leaves were collected from 12 sugar beet genotypes at four time points: seedling, early growth, root enlargement, and disease development stages. 1H-NMR spectra of foliar metabolites soluble in a deuterium-oxide (D2O-based buffer were acquired and subjected to multivariate analyses. A principal component analysis (PCA of the NMR data from the sugar beet leaves shows clear differences among the growth stages. At the later time points, the sugar and glycine betaine contents were increased, whereas the choline content was decreased. The relationship between the foliar metabolite profiles and resistance level to CLS was examined by combining partial least squares projection to latent structure (PLS or orthogonal PLS (OPLS analysis and univariate analyses. It was difficult to build a robust model for predicting precisely the disease severity indices (DSIs of each genotype; however, GABA and Gln differentiated susceptible genotypes (genotypes with weak resistance from resistant genotypes (genotypes with resistance greater than a moderate level before inoculation tests. The results suggested that breeders might exclude susceptible genotypes from breeding programs based on foliar metabolites profiled without inoculation tests, which require an enormous amount of time and effort.

Transmission of tomato spotted wilt tospovirus by Thrips tabaci populations originating from leek

NARCIS (Netherlands)

Chatzivassiliou, E.K.; Nagata, T.; Katis, N.I.; Peters, D.

1999-01-01

The transmission of tomato spotted wilt tospovirus (TSWV) by Thrips tabaci collected from leek was studied using the petunia local-lesion leaf-disc assay. After an acquisition-access period of 72 h given to newborn larvae up to 8 h old, the efficiency of transmission by adults was determined in

Quantitative trait loci associated with resistance to gray leaf spot and grain yield in corn QTLs associados à resistência a cercosporiose e produção de grãos em milho

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Adriano Delly Veiga

2012-02-01

Full Text Available The main objectives of hybrid development programs include incorporating genetic resistance to diseases and increasing grain yield. Identification of Quantitative Trait Loci (QTL through the statistical analysis of molecular markers allows efficient selection of resistant and productive hybrids. The objective of this research was to identify QTL associated with resistance to gray leaf spot and for grain yield in the germplasm of tropical corn. We used two strains with different degrees of reaction to the disease; the genotypes are owned by GENESEEDS Ltda, their F1 hybrid and the F2 population. The plants were evaluated for gray leaf spot resistance, for grain yield and were genotyped with 94 microsatellite markers. Association of the markers with the QTL was performed by single marker analysis using linear regression and maximum likelihood analysis. It was observed that the additive effect was predominant for genetic control of resistance to gray leaf spot, and the dominant effect in that of grain yield. The most promising markers to be used in studies of assisted selection are: umc2082 in bins 4.03 and umc1117 in bins 4.04 for resistance to gray leaf spot; for grain yield umc1042 in bins 2.07 and umc1058 in bins 4.11.A incorporação de resistência genética a doenças e o aumento na produtividade de grãos estão entre os principais objetivos dos programas de desenvolvimento de híbridos. A identificação de locos de caracteres quantitativos (QTL por meio de análises estatísticas associadas a marcadores moleculares possibilita a rápida obtenção de híbridos resistentes e produtivos. Nesta pesquisa, objetivou-se identificar locos de caracteres quantitativos (QTL associados com resistência à cercosporiose e com produção de grãos em germoplasma de milho tropical. Foram utilizadas duas linhagens contrastantes em níveis de reação à doença (genótipos pertencentes à GENESEEDS - Ltda, seu híbrido F1 e a população segregante F2

Multilocus sequence typing of Pseudomonas syringae sensu lato confirms previously described genomospecies and permits rapid identification of P. syringae pv. coriandricola and P. syringae pv. apii causing bacterial leaf spot on parsley.

Science.gov (United States)

Bull, Carolee T; Clarke, Christopher R; Cai, Rongman; Vinatzer, Boris A; Jardini, Teresa M; Koike, Steven T

2011-07-01

Since 2002, severe leaf spotting on parsley (Petroselinum crispum) has occurred in Monterey County, CA. Either of two different pathovars of Pseudomonas syringae sensu lato were isolated from diseased leaves from eight distinct outbreaks and once from the same outbreak. Fragment analysis of DNA amplified between repetitive sequence polymerase chain reaction; 16S rDNA sequence analysis; and biochemical, physiological, and host range tests identified the pathogens as Pseudomonas syringae pv. apii and P. syringae pv. coriandricola. Koch's postulates were completed for the isolates from parsley, and host range tests with parsley isolates and pathotype strains demonstrated that P. syringae pv. apii and P. syringae pv. coriandricola cause leaf spot diseases on parsley, celery, and coriander or cilantro. In a multilocus sequence typing (MLST) approach, four housekeeping gene fragments were sequenced from 10 strains isolated from parsley and 56 pathotype strains of P. syringae. Allele sequences were uploaded to the Plant-Associated Microbes Database and a phylogenetic tree was built based on concatenated sequences. Tree topology directly corresponded to P. syringae genomospecies and P. syringae pv. apii was allocated appropriately to genomospecies 3. This is the first demonstration that MLST can accurately allocate new pathogens directly to P. syringae sensu lato genomospecies. According to MLST, P. syringae pv. coriandricola is a member of genomospecies 9, P. cannabina. In a blind test, both P. syringae pv. coriandricola and P. syringae pv. apii isolates from parsley were correctly identified to pathovar. In both cases, MLST described diversity within each pathovar that was previously unknown.

Evaluation of the Incidence and Severity of Olive Leaf Spot caused by Spilocaea oleaginain different olive cultivars in Palestine

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Ruba Abuamsha

2013-12-01

Full Text Available Twelve olive (Olea europaea L. cultivars including Nabali Baladi, Nabali Mohassan, Santa Augustino, Nasohi Jaba`a 1, Nasohi Jaba`a 2, Yunani, Talmasani, Chemlali, Arbequino, Frantoio, Coca and Barouni, were sampled for their susceptibility to Spilocaea oleagina the causal agent for Olive leaf spot (OLS disease on olive trees in Palestine. Investigations were carried out to measure the incidence and severity of the disease at Qabatyia station in Jenin district area Susceptible olive cultivars grown commercially in Palestine include Arbequino, Frantoio and ?Barouni’.The “Nabali” is the most dominant and highly susceptible olive cultivar grown in Palestine. Disease incidence varied greatly among the cultivars F=59.4, df=11, 251, p?0.0001 and was correlated with the severity (y = 0.42x + 9.3, P ? 0.0001, R² = 0.84, y = disease severity and x = disease incidence. Disease severity also varied among different cultivars F=13.9, df=11, 251, p?0.0001. Nabali Mohassan was the most affected susceptible while Barouni was most resistant. Progress of disease severity over time fit the logistic function for all cultivars except for highly susceptible cultivars F=1.56, df=6, 83, p?0.169. The assessment method may be useful to screen olive cultivars for OLS resistance in Palestine.

Prevalence and diagnostic performance of computed tomography angiography spot sign for intracerebral hematoma expansion depend on scan timing

Energy Technology Data Exchange (ETDEWEB)

Tsukabe, Akio; Watanabe, Yoshiyuki; Tanaka, Hisashi; Kunitomi, Yuki; Nishizawa, Mitsuo; Arisawa, Atsuko; Tomiyama, Noriyuki [Osaka University Graduate School of Medicine, Department of Diagnostic and Interventional Radiology, Suita, Osaka (Japan); Yoshiya, Kazuhisa; Shimazu, Takeshi [Osaka University Graduate School of Medicine, Department of Traumatology and Acute Critical Medicine, Suita, Osaka (Japan)

2014-12-15

The computed tomography angiography (CTA) spot sign correlates with intracerebral hemorrhage (ICH) expansion; however, various diagnostic performances for hematoma expansion, especially in sensitivity, have been reported. We aimed to assess the impact of scan timing of CTA on the diagnostic performance of the CTA spot sign for ICH expansion in two different arterial phases within patients. Eighty-three consecutive patients with primary ICH who received two sequential CTAs were recruited. Two neuroradiologists reviewed CTAs for CTA spot signs, while one reviewed initial and follow-up non-contrast CT for measuring ICH volume. The time interval between two phases was then calculated, and the diagnostic performance of CTA spot sign in each phase was evaluated. CTA spot signs were observed in 20/83 (24.1 %) patients in the early phase and 44/83 (53.0 %) patients in the late phase. The mean time interval between the two phases was 12.7 s. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for hematoma progression of CTA spot sign were 48.1, 87.5, 65.0, 77.8, and 74.7 %, respectively, in early phase and 92.6, 66.1, 56.8, 94.9, and 74.7 %, respectively, in late phase. The CTA spot sign was significantly associated with ICH expansion in early (P < 0.001) and late (P < 0.00001) phases (Pearson's chi-square test). A mere 10-s difference in scan timing could make a difference on prevalence and diagnostic performance of the CTA spot sign, suggesting a need for the standardization of the CTA protocol to generalize the approach for effective clinical application. (orig.)

Faba Bean Can Adapt to Chocolate Spot Disease by Pretreatment with Shikimic and Salicylic Acids through Osmotic Adjustment, Solutes Allocation and Leaf Turgidity

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Heshmat S. Aldesuquy

2014-03-01

Full Text Available This study investigated the effect of shikimic and salicylic acids at the concentrations of 0.4 and 0.7 mM, respectively, or their combination as phenolic compounds and Ridomil MZ at the concentration of 250 g/100 L as a fungicide on osmotic pressure (OP, solutes allocation, organic acids, inorganic ions and relative water content were quantified in Vicia faba leaves infected by Botrytis fabae. Pathogen induced noticeable decrease in osmotic pressure, total soluble sugar (TSS and inorganic osmolytes (i.e. Na+, K+, Ca2+, Mg2+ and Cl- while caused obvious increase in proline, total soluble nitrogen (TSN and organic acids (i.e. Keto and citric acids in water extract of the leaf of faba bean plants. Furthermore, pathogen caused marked decrease in relative water content (RWC of infected leaves and as a consequence the saturation water deficit (SWD was increased. Exogenous application of shikimic acid, salicylic acid or their combination could counteract the adverse effects of B. fabae on osmotic adjustment by inducing additional increase in proline, total soluble sugars, total soluble nitrogen and organic acids which in turn increase the osmotic pressure as well as relative water content in leaves of infected plants. Recovery of osmotic adjustment as well as leaf turgidity of infected host by using these chemical inducers may encourage the using of them as protective control means. The results of the present study showed also that the application of chemical inducers such as shikimic and salicylic acids or their interaction increased the resistance of Vicia faba against the chocolate spot disease.

Dominant Species in Subtropical Forests Could Decrease Photosynthetic N Allocation to Carboxylation and Bioenergetics and Enhance Leaf Construction Costs during Forest Succession.

Science.gov (United States)

Xiao, Yihua; Liu, Shirong; Tong, Fuchun; Chen, Bufeng; Kuang, Yuanwen

2018-01-01

It is important to understand how eco-physiological characteristics shift in forests when elucidating the mechanisms underlying species replacement and the process of succession and stabilization. In this study, the dominant species at three typical successional stages (early-, mid-, and late-succession) in the subtropical forests of China were selected. At each stage, we compared the leaf construction costs (CC), payback time (PBT), leaf area based N content ( N A ), maximum CO 2 assimilation rate ( P max ), specific leaf area (SLA), photosynthetic nitrogen use efficiency (PNUE), and leaf N allocated to carboxylation ( N C ), and to bioenergetics ( N B ). The relationships between these leaf functional traits were also determined. The results showed that the early-succession forest is characterized with significantly lower leaf CC, PBT, N A , but higher P max , SLA, PNUE, N C , and N B , in relation to the late-succession forest. From the early- to the late-succession forests, the relationship between P max and leaf CC strengthened, whereas the relationships between N B , N C , PNUE, and leaf CC weakened. Thus, the dominant species are able to decrease the allocation of the photosynthetic N fraction to carboxylation and bioenergetics during forest succession. The shift in these leaf functional traits and their linkages might represent a fundamental physiological mechanism that occurs during forest succession and stabilization.

New Generation of Resistant Sugar Beet Varieties for Advanced Integrated Management of Cercospora Leaf Spot in Central Europe.

Science.gov (United States)

Vogel, Johannes; Kenter, Christine; Holst, Carsten; Märländer, Bernward

2018-01-01

Cercospora leaf spot (CLS) epidemics in sugar beet have been increasing in recent years causing higher use of fungicides. Concomitantly, the availability of effective fungicides is at risk because of resistance development in the fungus, the lack of new active ingredients as well as restrictive approval practices. A key option for an integrated management of CLS is cultivation of resistant varieties. Because of the yield penalty in resistant varieties, acceptance in commercial practice so far has been low. The aim of our study was to characterize recent sugar beet varieties registered in Germany in terms of resistance and tolerance to CLS and their value for integrated pest management. The genetic basis of CLS resistance in varieties is protected by intellectual property rights even after variety registration and not open to the public due to economic competition. To gain reliable data for cultivation, varieties have to be tested for their resistance traits under field conditions at varying levels of infection with Cercospora beticola . In collaboration with variety related stakeholders, 15 sugar beet varieties were tested in 49 field trials in Germany from 2014 to 2016 for their yield response to CLS. The trials were set up in a split-plot design with and without infection (i.e., with and without fungicide). The classification of varietal reaction to CLS is based on symptomatic leaf area (susceptibility) and the resulting relative yield loss (tolerance). Since the relation between both parameters varied among varieties, it was used as an additional parameter to describe tolerance. On this basis, three groups of varieties were identified. They can be characterized as a susceptible, a resistant and a presumably tolerant cluster. A comparison of the data with an older dataset originating from 2009 to 2011 revealed that yield performance of recent varieties with resistance to C. beticola caught up with susceptible varieties due to breeding progress. They showed no

A Risk Assessment Model for Bacterial Leaf Spot of Pepper (Capsicum annuum), Caused by Xanthomonas euvesicatoria, Based on Concentrations of Macronutrients, Micronutrients, and Micronutrient Ratios.

Science.gov (United States)

Dutta, B; Langston, D B; Luo, X; Carlson, S; Kichler, J; Gitaitis, R

2017-11-01

The phytopathogenic bacterium Xanthomonas euvesicatoria causes bacterial leaf spot (BLS) of pepper and has a worldwide distribution. BLS is difficult to control and an integrated management strategy that incorporates crop rotation, use of clean seed and clean plants, weed control, resistant varieties, applications of bactericides, biocontrol agents, and systemic acquired resistance (SAR) inducers is generally recommended. However, even with that arsenal of weapons, BLS can still be responsible for severe losses under favorable environmental conditions. Thus, additional tools need to be added to an overall integrated management strategy to combat BLS. In this article, we developed several models from 2012 to 2014 that were based on how macronutrients, micronutrients, and micronutrient ratios affect BLS severity. Factors used to select a model for validation included highly significant P values, high adjusted R 2 values, low variance inflation factor values (macronutrient and micronutrient concentrations affect plant disease resistance genes in the SAR pathway.

Reading the Leaves: A Comparison of Leaf Rank and Automated Areole Measurement for Quantifying Aspects of Leaf Venation

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Walton A. Green

2014-08-01

Full Text Available The reticulate venation that is characteristic of a dicot leaf has excited interest from systematists for more than a century, and from physiological and developmental botanists for decades. The tools of digital image acquisition and computer image analysis, however, are only now approaching the sophistication needed to quantify aspects of the venation network found in real leaves quickly, easily, accurately, and reliably enough to produce biologically meaningful data. In this paper, we examine 120 leaves distributed across vascular plants (representing 118 genera and 80 families using two approaches: a semiquantitative scoring system called “leaf ranking,” devised by the late Leo Hickey, and an automated image-analysis protocol. In the process of comparing these approaches, we review some methodological issues that arise in trying to quantify a vein network, and discuss the strengths and weaknesses of automatic data collection and human pattern recognition. We conclude that subjective leaf rank provides a relatively consistent, semiquantitative measure of areole size among other variables; that modal areole size is generally consistent across large sections of a leaf lamina; and that both approaches—semiquantitative, subjective scoring; and fully quantitative, automated measurement—have appropriate places in the study of leaf venation.

Seleção de famílias de feijoeiro resistente à antracnose e à mancha-angular Selection of common bean families resistant to anthracnose and angular leaf spot

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Marcelo Geraldo de Morais Silva

2006-10-01

Full Text Available O objetivo deste trabalho foi identificar famílias de feijoeiro com resistência a Colletotrichum lindemuthianum e Phaeoisariopsis griseola e com outros fenótipos agronômicos desejáveis. As famílias utilizadas foram obtidas do cruzamento entre a linhagem H91, portadora de três alelos de resistência à antracnose, com três famílias F2:5 resistentes à mancha-angular, derivadas da cultivar Jalo EEP 558. Foi utilizado o delineamento látice quadrado em todos os experimentos. Inicialmente, foram avaliadas 144 famílias F2:3, no inverno de 2004, em Lavras, MG, com base no tipo de grão. Foram selecionadas 80 famílias F2:4 e avaliadas com a testemunha BRSMG Talismã, no período das águas de 2004/2005, no mesmo local. Considerando-se o tipo de grão e a resistência à mancha-angular e antracnose, foram mantidas 48 famílias F2:5, que foram avaliadas na seca de 2005, em Lavras e Lambari, MG. Essas 48 famílias passaram por inoculação das raças 2047, 73 e 1545 de C. lindemuthianum, para verificação da presença dos alelos de resistência Co-4², Co-5 e Co-7, respectivamente. Foram identificados genótipos da maioria das 48 famílias, quanto à reação à antracnose, das quais se destacaram quatro, em relação ao tipo de grão semelhante ao 'Carioca', de porte ereto, produtividade elevada e resistência à mancha-angular.The objective of this work was to select common bean families resistant to Colletotrichum lindemuthianum and Phaeoisariopsis griseola and, also, with superior agronomical traits. Families used were obtained from crosses of H91 lineage, bearer of three alleles resistant to anthracnose, and F2;5 families derived from the cultivar Jalo EEP 558, which is resistant to angular leaf spot. Square lattice design was used in all experiments. Initially the F2:3 families (144 were evaluated in the winter of 2004, in Lavras county, MG, Brazil, based on grain type. Eighty families (F2:4 were selected and evaluated with the check

Chapter 4: Northern spotted owl habitat and populations: Status and threats

Science.gov (United States)

Lesmeister, Damon B.; Davis, Ramond J; Singleton, Peter H; Wiens, David

2018-01-01

The northern spotted owl (Strix occidentalis caurina) was listed as threatened under the Endangered Species Act in 1990 (USFWS 1990). Providing adequate amounts of suitable forest cover to sustain the subspecies was a major component of the first recovery plan for northern spotted owls (USFWS 1992) and a driver in the basic reserve design and old-forest restoration under the Northwest Forest Plan (NWFP, or Plan) (USDA and USDI 1994). The reserve design included large contiguous blocks of late-successional forest, which was expected to be sufficient to provide habitat for many interacting pairs of northern spotted owls. As such, the selection of reserves generally favored areas with the highest quality old-growth

Evaluation of indigenous bacterial strains for biocontrol of the frogeye leaf spot of soya bean caused by Cercospora sojina.

Science.gov (United States)

Simonetti, E; Carmona, M A; Scandiani, M M; García, A F; Luque, A G; Correa, O S; Balestrasse, K B

2012-08-01

Assessment of biological control of Cercospora sojina, causal agent of frogeye leaf spot (FLS) of soya bean, using three indigenous bacterial strains, BNM297 (Pseudomonas fluorescens), BNM340 and BNM122 (Bacillus amyloliquefaciens). From cultures of each bacterial strain, cell suspensions and cell-free supernatants were obtained and assayed to determine their antifungal activity against C. sojina. Both mycelial growth and spore germination in vitro were more strongly inhibited by bacterial cell suspensions than by cell-free supernatants. The Bacillus strains BNM122 and BNM340 inhibited the fungal growth to a similar degree (I ≈ 52-53%), while cells from P. fluorescens BNM297 caused a lesser reduction (I ≈ 32-34%) in the fungus colony diameter. The foliar application of the two Bacillus strains on soya bean seedlings, under greenhouse conditions, significantly reduced the disease severity with respect to control soya bean seedlings and those sprayed with BNM297. This last bacterial strain was not effective in controlling FLS in vivo. Our data demonstrate that the application of antagonistic bacteria may be a promising and environmentally friendly alternative to control the FLS of soya bean.   To our knowledge, this is the first report of biological control of C. sojina by using native Bacillus strains. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

Association Mapping of Quantitative Trait Loci in Spring Wheat Landraces Conferring Resistance to Bacterial Leaf Streak and Spot Blotch

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Tika B. Adhikari

2012-03-01

Full Text Available Bacterial leaf streak (BLS, caused by pv. (Smith et al. Bragard et al., and spot blotch (SB, caused by (S. Ito & Kurib. Drechs. ex Dastur, are two emerging diseases of wheat ( L.. To achieve sustainable disease management strategies and reduce yield losses, identifying new genes that confer quantitative resistance would benefit resistance breeding efforts. The main objective of this study was to use association mapping (AM with 832 polymorphic Diversity Arrays Technology (DArT markers to identify genomic regions associated with resistance to BLS and SB in 566 spring wheat landraces. From data analysis of this diverse panel of wheat accessions, we discovered five novel genomic regions significantly associated with resistance to BLS on chromosomes 1A, 4A, 4B, 6B, and 7D. Similarly, four genomic regions were found to be associated with resistance to SB on chromosomes 1A, 3B, 7B, and 7D. A high degree of linkage disequilibrium (LD decayed over short genetic distance in the set of wheat accessions studied, and some of these genomic regions appear to be involved in multiple disease resistance (MDR. These results suggest that the AM approach provides a platform for discovery of resistance conditioned by multiple genes with quantitative effects, which could be validated and deployed in wheat breeding programs.

Peach leaf responses to soil and cement dust pollution.

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Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

2015-10-01

Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

Construction and characterization of a bacterial artificial chromosome library of the causal agent of Black Sigatoka fungal leaf spot disease of banana and plantain, Mycosphaerella fijiensis.

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Canto-Canché, Blondy; Guillén-Maldonado, Diana Karina; Peraza-Echeverría, Leticia; Conde-Ferráez, Laura; James-Kay, Andrew

2007-05-01

A bacterial artificial chromosome library of the causal agent of the Black Sigatoka leaf spot disease of banana and plantain, Mycosphaerella fijiensis, has been constructed using a non-sphaeroplasting technique and characterized using both homologous and heterologous probes. After first and a second size selection of PFGE-fractionated DNA, a ligation was obtained using a 1:4 molar ratio (insert:vector). One hundred random clones were analyzed, and the mean insert size was estimated to be 90 kb. The range of the insert sizes was between 40 and 160 kb. The highest percentage of inserts belonged to the range between 80 and 100 kb; 32% of the inserts had 2 or 3 internal NotI sites. This library consists of 1920 clones, if the genomic size is at least 35 Mb, then this represents 4.9 x genome equivalents, which was supported by hybridization results with homologous and heterologous probes.

Reação de cultivares de trigo à ferrugem da folha e mancha amarela e responsividade a fungicidas Reaction of wheat cultivars to leaf rust and yellow spot and responsiveness to fungicides

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Nédio Rodrigo Tormen

2013-02-01

Full Text Available Com o objetivo de avaliar a reação de cultivares de trigo à ferrugem da folha, causada por Puccinia triticina, e mancha amarela, causada por Drechslera tritici-repentis, e sua responsividade ao controle químico com fungicidas, foi conduzido experimento de campo durante os invernos de 2009 e 2010, Itaara-RS. As cultivares avaliadas foram 'FCEP 51', 'FCEP 52', 'CD 114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' e 'OR Pampeano'; na safra 2010, a cultivar 'CD 114' foi substituída pela OR Quartzo. Os tratamentos avaliados foram: P1 - testemunha sem aplicação de fungicida; P2 - fempropimorfe (560g ha-1 de i.a.; P3 - azoxistrobina + ciproconazol (60+24g ha-1 de i.a.; e P4 - piraclostrobina + metconazol (60+97,5g ha-1 de i.a.. Após a segunda aplicação, efetuaram-se avaliações semanais de severidade das doenças, cujos dados foram utilizados para o cálculo da Área Abaixo da Curva de Progresso da Doença (AACPD. Também foram determinados a produtividade e o peso do hectolitro. No que se refere à suscetibilidade às doenças, as cultivares estudadas apresentaram respostas distintas de um ano para o outro. Para ferrugem, o comportamento mostrou-se similar em ambos os anos, enquanto que, para mancha amarela, houve variação. Quanto à resposta ao controle químico, ocorreram variações de acordo com o patógeno e com o grau de suscetibilidade das cultivares. O uso integrado de resistência genética e controle químico mostrou-se mais efetivo para ferrugem da folha.Aiming to evaluate the susceptibility of wheat cultivars to leaf rust and yellow spot and their responsiveness to chemical fungicides, two field trials were carried out, during 2009 and 2010 winter's. The cultivars evaluated were: 'FCEP 51', 'FCEP 52', 'CD114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' and 'OR Pampeano'. In 2010, the 'CD 114' cultivar was replaced by Quartzo

Stomatal conductance, canopy temperature, and leaf area index estimation using remote sensing and OBIA techniques

Science.gov (United States)

S. Panda; D.M. Amatya; G. Hoogenboom

2014-01-01

Remotely sensed images including LANDSAT, SPOT, NAIP orthoimagery, and LiDAR and relevant processing tools can be used to predict plant stomatal conductance (gs), leaf area index (LAI), and canopy temperature, vegetation density, albedo, and soil moisture using vegetation indices like normalized difference vegetation index (NDVI) or soil adjusted...

A magnetic study of spotted UV Ceti flare stars and related late-type dwarfs

Science.gov (United States)

Vogt, S. S.

1980-09-01

A multichannel photoelectric Zeeman analyzer has been used to investigate the magnetic nature of the spotted UV Ceti flare stars. Magnetic observations were obtained on a sample of 19 program objects, of which 5 were currently spotted dKe-dMe stars, 7 were normal dK-dM stars, 7 were UV Ceti flare stars, and 1 was a possible post-T Tauri star. Contrary to most previously published observations and theoretical expectations, no magnetic fields were detected on any of these objects from either the absorption lines or the H-alpha emission line down to an observational uncertainty level of 100-160 gauss (standard deviation).

A Comparison of Leaf Area Index Maps Derived from Multi-Sensor Optical Data Acquired over Agricultural Areas

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Giuseppe Satalino

2010-06-01

Full Text Available The objective of this study is to retrieve and compare Leaf Area Index (LAI maps from temporal series of SPOT, IKONOS and MERIS images acquired, from 2006 to 2008, over an agricultural site in Southern Italy. Results show that the root mean square error (RMSE of LAI derived from MERIS data is approximately 1 m2 m-2, slightly larger than the one obtained by using SPOT and IKONOS data. In addition, LAI retrieved from MERIS data tends to underestimate LAI retrieved from SPOT and IKONOS data, particularly at low LAI values. Nevertheless, the paper gives examples highlighting the strength of MERIS with respect to SPOT and IKONOS data in providing long and dense temporal series of LAI maps suitable to feature the temporal evolution of vegetation growth at regional scale.

Timing and duration of autumn leaf development in Sweden

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Bolmgren, Kjell

2014-05-01

The growing season is changing in both ends and autumn phases seem to be responding in more diverse ways than spring events. Indeed, we know little about autumn leaf phenological strategies and how they are correlated with fitness components or ecosystem properties, and how they vary between species and over bioclimatic gradients. In this study more than 10 000 students were involved in observing autumn leaf development at 378 sites all over Sweden (55-68°N). They followed an image based observation protocol classifying autumn leaf development into five levels, from summer green (level 0) to 100% autumn leaf colored (level 4) canopy. In total, they submitted almost 12 000 observations between August 9 and November 15. 75% of the observations were made on the common species of Populus tremula, Betula pendula/pubescens and Sorbus aucuparia. The expected (negative) correlation between latitude and start of leaf senescence (level 2) was found in Populus and Betula, but not in Sorbus. The duration of the leaf senescence period, defined as the period between 1/3 (level 2) and 100% (level 4) of the canopy autumn leaf colored, was negatively correlated with latitude in Populus and Betula, but not in Sorbus. There was also a strong (negative) correlation of the start (level 2) and the duration of the leaf senescence in the early senescing Sorbus and Betula, while this effect was weaker in the late senescing Populus.

Observations of the late superhump in VW Hydri

International Nuclear Information System (INIS)

Van Der Woerd, H.; Van Der Klis, M.; Van Paradijs, J.; Beuermann, K.; Motch, C.

1988-01-01

This paper presents the results of simultaneous optical and near-IR photometry, optical fast spectroscopy, and Exosat X-ray observations of the dwarf nova VW Hyi, obtained simultaneously during three consecutive orbital cycles, approximately two days after the 1983 November superoutburst terminated. The optical data show clear evidence for a late superhump, which is shifted + 0.7 in phase relative to the orbital modulation. An attempt is made to derive from the observed spectral distribution the contribution of the late superhump. The orbital hump and the late superhump apparently are not related to each other. This important effect excludes all models, in which the late superhump phenomenon is interpreted in terms of variations in the bright-spot brightness. 43 references

Melhoramento do feijoeiro comum com grão tipo carioca, visando resistência à antracnose e à mancha angular Breeding of common bean with carioca type grain for the resistance to anthracnose and angular leaf spot

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Mansuêmia Alves Couto

2008-10-01

Full Text Available Objetivou-se no trabalho, selecionar linhagens de feijoeiro comum que reunissem, além da alta produtividade, porte ereto e grãos do tipo Carioca, também a resistência à antracnose e à mancha angular. O material experimental constituiu-se de 143 linhagens oriundas de três famílias segregantes F1:4RC2 {[(G2333 X ESAL 696 X ESAL 696] X CI 140}. Foram conduzidos quatro experimentos em três localidades da região sul de Minas Gerais, avaliando-se a produção, o tipo de grão, o porte e a reação à mancha angular. A reação à antracnose foi determinada a partir de inoculações de plantas jovens de cada linhagem, com as raças 2047 e 1545, mantidas em câmara de nevoeiro por três dias e transferidas para casa de vegetação com irrigação por aspersão, a cada quatro horas. Selecionaram-se quatro linhagens com alta produtividade, porte mais arbustivo, grãos tipo carioca e com resistência à mancha angular (nota até 4. Uma das linhagens selecionada possui o alelo Co-4², outras duas possuem o alelo Co-7 de resistência à antracnose e a última, embora seja suscetível à antracnose, possui resistência à mancha angular (nota 3,97 e maior produtividade de grãos.Aiming to select common bean lines with high grain yield, Carioca grain type, upright plant habit and resistant to anthracnose and angular leaf spot, 143 lines were selected from three families of the cross F1:4RC2 {[(G2333 X ESAL 696 X ESAL 696] X CI 140}. The promising lines were selected based on the agronomical traits in four field experiments, set up in three places in Southern MG State using the square lattice design. The reaction of each line to the anthracnose was evaluated by inoculating the seedlings using the races 1545 and 2047, and kept in humid chamber during three days, and then moved to greenhouse with sprinkle irrigation every four hours. Four lines with high grain yield, upright plant habit, Carioca grain type, and resistance to angular leaf spot (score up

Survey and prevalence of species causing Alternaria leaf spots on brassica species in Pernambuco Levantamento e prevalência de espécies causadoras da alternariose em brássicas em Pernambuco

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Sami J Michereff

2012-06-01

Full Text Available Brassicaceae family comprises plant species that are very important as vegetable crops, such as the species complex Brassica oleracea and Brassica rapa. Alternaria brassicicola and A. brassicae are among the most important pathogens of Brassicaceae causing Alternaria leaf spot disease. The occurrence and prevalence of Alternaria species causing leaf spots in brassica crops in Pernambuco was acessed, as well as the existence of a possible preference by vegetable host for these pathogens. Twenty-eight fields were surveyed in the Agreste region of Pernambuco state, in the 2005 and 2006 growing seasons. In each year, 10 Chinese cabbage, six cabbage, six cauliflower and six broccoli fields were visited. In each field, 50 leaves showing at least five lesions were randomly collected. Species identification was performed taking into account morphology of the conidia that was compared with literature data. Among the two Alternaria species found, A. brassicae was found in all Chinese cabbage fields while A. brassicicola was found in all fields of cabbage, cauliflower and broccoli. Overall, A. brassicicola was more prevalent than A. brassicae. In Chinese cabbage there was predominance of A. brassicae, with mean prevalence of 91.0% and 96.5% in 2005 and 2006. On the other hand, in broccoli and cabbage there was high predominance of A. brassicicola, with mean prevalence between 95.1% and 99.8%. In cauliflower, although the prevalence has been of A. brassicicola, high frequency of A. brassicae was noted. The frequency of co-occurrence of both Alternaria species was very low. The results of this study reinforce the hypothesis of existence of host preference within species of Alternaria that cause leaf spots in brassica crops, especially when Chinese cabbage, broccoli and cabbage are considered. This information is critical to developing strategies for managing Alternaria leaf spots in Brassicaceae species.A família Brassicaceae possui espécies importantes

Generation of an Infectious Clone of a New Korean Isolate of Apple chlorotic leaf spot virus Driven by Dual 35S and T7 Promoters in a Versatile Binary Vector

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Ik-Hyun Kim

2017-12-01

Full Text Available The full-length sequence of a new isolate of Apple chlorotic leaf spot virus (ACLSV from Korea was divergent, but most closely related to the Japanese isolate A4, at 84% nucleotide identity. The full-length cDNA of the Korean isolate of ACLSV was cloned into a binary vector downstream of the bacteriophage T7 RNA promoter and the Cauliflower mosaic virus 35S promoter. Chenopodium quinoa was successfully infected using in vitro transcripts synthesized using the T7 promoter, detected at 20 days post inoculation (dpi, but did not produce obvious symptoms. Nicotiana occidentalis and C. quinoa were inoculated through agroinfiltration. At 32 dpi the infection rate was evaluated; no C. quinoa plants were infected by agroinfiltration, but infection of N. occidentalis was obtained.

Distribution of Tomato spotted wilt virus in dahlia plants.

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Asano, S; Hirayama, Y; Matsushita, Y

2017-04-01

Tomato spotted wilt virus (TSWV) causes significant losses in the production of the ornamental plant Dahlia variabilis in Japan. The purpose of this study was to examine the distribution of TSWV in dahlia plants and identify plant parts that can be used in the selection of TSWV-free plants. The distribution of TSWV was investigated using reverse transcriptional polymerase chain reaction (RT-PCR) and tissue blot immunoassay. The detection rate of TSWV in latent infected compound leaves was the highest in the petiole, and it decreased from the veins and rachis to the lamina. The tissue blot immunoassays of the leaflets showed an uneven distribution of TSWV, especially along the edge of the leaf blade. In stems, the detection rate of TSWV was high partway up the stem compared to that in the upper and the lower parts of the stem during the vegetative growth stage. A highly uneven distribution was observed in the bulb. Our results indicated that middle parts of the stem as well as the petioles, rachis, and veins of compound leaves are suitable for detection of TSWV in dahlias. This study is the first to report uneven distribution of TSWV in dahlia plants. In this study, the distribution of Tomato spotted wilt virus (TSWV) in various parts of dahlia plants was investigated for the first time. The distribution of TSWV was uneven in compound leaves, leaflets, stems, and bulbs. The middle parts of the stem or the petiole and leaf veins should be sampled to detect TSWV when selecting healthy plants. © 2017 The Society for Applied Microbiology.

Biological control of bacterial spot of tomato by saprobe fungi from semi-arid areas of northeastern Brazil

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Douglas Casaroto Peitl

2017-06-01

Full Text Available Bacterial spot of tomato, caused by Xanthomonas spp., is a common disease in tomato fields that causes significant economic losses. Due to the difficulty with control of bacterial spot by conventional methods, new techniques such as biological control and induction of resistance are gaining prominence. This study aimed to select saprobe fungi from semi-arid regions of the Brazilian Northeast for the biological control of bacterial spot of tomato. To select the best isolates to control bacterial spot, a greenhouse experiment was initially conducted. Tomato plants (‘Santa Cruz Kada’ were treated with filtrates of 25 saprobe fungi and inoculated three days later with Xanthomonas euvesicatoria. Filtrates of Memnoniella levispora, Periconia hispidula, Zygosporium echinosporum, and Chloridium virescens var. virescens were selected as the most effective. Filtrates and volatile compounds from these four isolates were tested for their antibacterial activity in cultures of X. euvesicatoria and in tomato plants (‘Santa Cruz Kada’ inoculated with X. euvesicatoria. In vitro, the addition of nonvolatile fungal metabolites into the culture medium at 5% and 50% (v/v inhibited bacterial growth by 28.9% and 53.8%, respectively. The volatile compounds produced by C. virescens var. virescens reduced the number of colony-forming units of X. euvesicatoria by 25.9%. In vivo, all treatments reduced from 62.4 to 71.3% the area under bacterial spot progress curve, showing the same control efficacy as the commercial resistance inducer used as a positive control (acibenzolar-S-methyl. Systemicity of the fungal filtrates was confirmed in a separate experiment, where application of the treatments exclusively to the third leaf decreased the severity of the disease on the fourth leaf (except for C. virescens var. virescens. These results show that M. levispora, P. hispidula, Z. echinosporum, and C. virescens var. virescens are potential biocontrol agents against

Combining powers of linkage and association mapping for precise dissection of QTL controlling resistance to gray leaf spot disease in maize (Zea mays L.).

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Mammadov, Jafar; Sun, Xiaochun; Gao, Yanxin; Ochsenfeld, Cherie; Bakker, Erica; Ren, Ruihua; Flora, Jonathan; Wang, Xiujuan; Kumpatla, Siva; Meyer, David; Thompson, Steve

2015-11-10

Gray Leaf Spot (GLS causal agents Cercospora zeae-maydis and Cercospora zeina) is one of the most important foliar diseases of maize in all areas where the crop is being cultivated. Although in the USA the situation with GLS severity is not as critical as in sub-Saharan Africa or Brazil, the evidence of climate change, increasing corn monoculture as well as the narrow genetic base of North American resistant germplasm can turn the disease into a serious threat to US corn production. The development of GLS resistant cultivars is one way to control the disease. In this study we combined the high QTL detection power of genetic linkage mapping with the high resolution power of genome-wide association study (GWAS) to precisely dissect QTL controlling GLS resistance and identify closely linked molecular markers for robust marker-assisted selection and trait introgression. Using genetic linkage analysis with a small bi-parental mapping population, we identified four GLS resistance QTL on chromosomes 1, 6, 7, and 8, which were validated by GWAS. GWAS enabled us to dramatically increase the resolution within the confidence intervals of the above-mentioned QTL. Particularly, GWAS revealed that QTLGLSchr8, detected by genetic linkage mapping as a locus with major effect, was likely represented by two QTL with smaller effects. Conducted in parallel, GWAS of days-to-silking demonstrated the co-localization of flowering time QTL with GLS resistance QTL on chromosome 7 indicating that either QTLGLSchr7 is a flowering time QTL or it is a GLS resistance QTL that co-segregates with the latter. As a result, this genetic linkage - GWAS hybrid mapping system enabled us to identify one novel GLS resistance QTL (QTLGLSchr8a) and confirm with more refined positions four more previously mapped QTL (QTLGLSchr1, QTLGLSchr6, QTLGLSchr7, and QTLGLSchr8b). Through the novel Single Donor vs. Elite Panel method we were able to identify within QTL confidence intervals SNP markers that would be

Mutant of Japanese pear resistant to Black Spot Disease

International Nuclear Information System (INIS)

Sanada, T.; Nishida, T.; Ikeda, F.

1987-01-01

Full text: Nijisseike is one of the leading cultivars of Japanese pear (Pyrus serotinea Rehd.), but susceptible to black spot disease. Farmers try to prevent this disease by wrapping the fruit with a paper bag and by repeated spraying of fungicides. The disease is caused by a Japanese pear pathotype of Alternaria alternata (Fr.) Keissler. Susceptibility is controlled by a single dominant gene. In 1962, grafted trees of this cultivar were planted at a distance between 53 and 93 m from the 60 Co source in the gamma-field (daily dose 15-4 rad). One branch on a tree planted at 53 m was detected as resistant in 1981. Under field conditions, black spots were observed on many fruits and leaves of the original trees by natural infection in early July, however, they were not observed on the mutant. To examine the resistance of the mutant, artificial inoculations were made using spores of the pathogen and the host specific toxin produced by germinating spores. When some drops of the spore suspension are placed on leaves, the formation of black spots depends upon the leaf age. In a resistant cv. as Chojuro, black spot symptoms are formed only when inoculated on young leaves. An intermediate reaction was observed in the mutant, whereas the original Nijisseiki showed severe symptoms. When inoculation was made on matured fruit skins, no black spot was formed on the mutant just like on the resistant cv. Chojuro, while many small black spots were formed and grew into large spots overlapping each other on the susceptible cv. Nijisseiki. In case of the crude toxin inoculation (4-0.04 ppm) of cv. Nijisseiki black spots were formed on the surface of the susceptible fruit skin, and necrotic lesions at the cut end of detached small pieces of leaves, although reaction on fruit skins was weaker compared with inoculation by spores. However, no symptoms were observed from the toxin application on the mutant and the resistant cv. Chojuro. That the resistance of the mutant is classified as

Elaboração e validação de escala diagramática para a cercosporiose do pimentão Development and validation of a diagrammatic key for Cercospora leaf spot of sweet pepper

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Sami Jorge Michereff

2006-09-01

Full Text Available A cercosporiose do pimentão, causada pelo fungo Cercospora capsici, é uma importante doença que ocorre em condições tropicais. Devido à inexistência de métodos padronizados para quantificação desta doença em campo, uma escala diagramática com os níveis de 1,5; 3,5; 8,0; 16,5; 31,0 e 50% de área foliar lesionada foi elaborada e testada para a acurácia, a precisão e a reprodutibilidade das estimativas de severidade da cercosporiose do pimentão, sem e com a sua utilização. Na validação da escala diagramática, 50 folhas com diferentes níveis de severidade da doença, mensurados previamente com o programa AutoCAD®, foram avaliadas por 13 avaliadores, sem e com a utilização da escala diagramática. Foram realizadas duas avaliações com utilização da escala, com intervalo de sete dias, onde seqüências diferentes das mesmas folhas foram estimadas visualmente pelos mesmos avaliadores. A acurácia e a precisão de cada avaliador foi determinada por regressão linear simples, entre a severidade real e a estimada. Sem a escala, oito avaliadores superestimaram significativamente a severidade da doença. Com a escala, os avaliadores obtiveram melhores níveis de acurácia e precisão, embora quatro tendessem a superestimar a severidade, com os erros absolutos concentrando-se abaixo de 10%. Os avaliadores apresentaram boa repetibilidade e elevada reprodutibilidade das estimativas com a utilização da escala, o mesmo não sendo verificado sem a utilização desta. A escala diagramática proposta mostrou-se adequada para avaliação da severidade da cercosporiose do pimentão.Cercospora leaf spot of sweet pepper caused by the fungus Cercospora capsici is an important disease occurring in tropical conditions. Due to the inexistence of standard methods to quantify this disease in field conditions, a diagrammatic key including the levels 1.5, 3.5, 8.0,16.5, 31.0 and 50.0% of diseased leaf area was elaborated and tested for accuracy

Protein profiling in potato (Solanum tuberosum L.) leaf tissues by differential centrifugation.

Science.gov (United States)

Lim, Sanghyun; Chisholm, Kenneth; Coffin, Robert H; Peters, Rick D; Al-Mughrabi, Khalil I; Wang-Pruski, Gefu; Pinto, Devanand M

2012-04-06

Foliar diseases, such as late blight, result in serious threats to potato production. As such, potato leaf tissue becomes an important substrate to study biological processes, such as plant defense responses to infection. Nonetheless, the potato leaf proteome remains poorly characterized. Here, we report protein profiling of potato leaf tissues using a modified differential centrifugation approach to separate the leaf tissues into cell wall and cytoplasmic fractions. This method helps to increase the number of identified proteins, including targeted putative cell wall proteins. The method allowed for the identification of 1484 nonredundant potato leaf proteins, of which 364 and 447 were reproducibly identified proteins in the cell wall and cytoplasmic fractions, respectively. Reproducibly identified proteins corresponded to over 70% of proteins identified in each replicate. A diverse range of proteins was identified based on their theoretical pI values, molecular masses, functional classification, and biological processes. Such a protein extraction method is effective for the establishment of a highly qualified proteome profile.

Seleção de linhagens de feijão rosinha de boa cocção, resistentes à antracnose e mancha angular Selection of pink grain common bean lines with good cooking ability, resistance to anthracnose and angular leaf spot

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Diego Velásquez Faleiro e Silva

2009-09-01

Full Text Available Cultivares de feijoeiro com grão rosinha foram de grande importância, no passado, e ainda hoje, mesmo com a preferência pelo grão carioca, há nichos de mercado para feijões do grupo Rosinha. Dessa forma, o objetivo do trabalho foi selecionar linhagens de feijoeiro comum com grão rosinha, alta produção de grãos, rápido cozimento e resistentes à antracnose e à mancha angular. A partir de cinco famílias F8 superiores, provenientes do cruzamento entre os genitores Rosinha Maria da Fé e ESAL 693, foram extraídas 143 linhagens as quais foram avaliadas na safra das águas de 2005/2006 em Lavras (MG. Dessas, manteve-se 99 linhagens que foram avaliadas em Lavras e Lambari (MG, na safra da seca de 2006. As 24 linhagens selecionadas foram novamente avaliadas nos dois locais, no inverno de 2006. Os caracteres avaliados foram produção e tipo de grão, tempo de cocção, reação à mancha angular e também, foi realizado o teste de resistência ao patótipo 65 de Colletotrichum lindemuthianum. Nas linhagens, observaram-se variabilidade genética para todos os caracteres avaliados, altas estimativas dos coeficientes de herdabilidade, assegurando elevados ganhos com a seleção. Foram selecionadas quatro linhagens com alta produção, tipo de grão ideal, com rápido tempo de cocção e resistência à mancha angular e à antracnose.Common bean cultivars with pink grain type used to be very important, although there is still some market spot for them. The objective of the research was to select common bean lines with pink grain, high grain yield with good cooking ability, and resistance to anthracnose and angular leaf spot. One hundred and forty three lines were selected from five F8 segregant families derived from the cross Rosinha Maria da Fé x ESAL 693. Those lines were evaluated in the rainy season of 2005/2006 at Lavras county, MG State. Ninety nine lines were kept and tested in the dry season of 2006 at Lavras and Lambari. The 24

Leaf Diseases On Eucalyptus Pellita F. Muell In Plantation Of Pt Surya Hutani Jaya At Sebulu East Kalimantan

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Iin Arsensi

2015-08-01

Full Text Available Eucalyptus pellita is often grown in monoculture can be susceptible to disease whether grown in the nursery or the field. Currently in the plantation of PT Surya Hutani Jaya Sebulu is developing E. pellita derived from seed and clonal. The results were then called family. To determine the benefits to trees the company deliberately does not preserve this area so there will be generated trees family that excel in both productivity and resistance to pests and diseases. This study is aimed at determining the symptoms and signs of disease on the leaves the microorganisms that cause disease on the leaves as well as the incidence and severity of pathogen that attacks the leaves of E. pellita. The research was conducted at PT Surya Hutani Jaya Sebulu Kutai Kartanegara Regency East Kalimantan and continued with the identification of pathogens at the Laboratory of Forest Protection Faculty of Forestry University of Mulawarman. The object of this research was E. pellita of a 6 year old plantation spacing of 3 amp61620 2 m. The origin of E. pellita is a clone from Riau. Symptoms of the disease found at the progeny test were leaf spot and leaf blight. The pathogens were Cercospora sp. Pestalotia sp. Curvularia sp. Bipolaris sp. Marsonina sp. and Dactylaria sp. The incidence of leaf spot pathogen was 83.3 and leaf blight was 80.6 with the severity of 9.7 and 12.5 respectively.

The Cucumber leaf spot virus p25 auxiliary replicase protein binds and modifies the endoplasmic reticulum via N-terminal transmembrane domains

Energy Technology Data Exchange (ETDEWEB)

Ghoshal, Kankana [University of British Columbia, Faculty of Land and Food Systems, Vancouver, British Columbia, Canada V6T 1Z4 (Canada); Theilmann, Jane; Reade, Ron; Sanfacon, Helene [Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0 (Canada); Rochon, D’Ann, E-mail: dann.rochon@agr.gc.ca [University of British Columbia, Faculty of Land and Food Systems, Vancouver, British Columbia, Canada V6T 1Z4 (Canada); Agriculture and Agri-Food Canada Pacific Agri-Food Research Centre, 4200 Hwy 97, Summerland, British Columbia, Canada V0H 1Z0 (Canada)

2014-11-15

Cucumber leaf spot virus (CLSV) is a member of the Aureusvirus genus, family Tombusviridae. The auxiliary replicase of Tombusvirids has been found to localize to endoplasmic reticulum (ER), peroxisomes or mitochondria; however, localization of the auxiliary replicase of aureusviruses has not been determined. We have found that the auxiliary replicase of CLSV (p25) fused to GFP colocalizes with ER and that three predicted transmembrane domains (TMDs) at the N-terminus of p25 are sufficient for targeting, although the second and third TMDs play the most prominent roles. Confocal analysis of CLSV infected 16C plants shows that the ER becomes modified including the formation of punctae at connections between ER tubules and in association with the nucleus. Ultrastructural analysis shows that the cytoplasm contains numerous vesicles which are also found between the perinuclear ER and nuclear membrane. It is proposed that these vesicles correspond to modified ER used as sites for CLSV replication. - Highlights: • The CLSV p25 auxiliary replicase targets the endoplasmic reticulum (ER). • Targeting of CLSV p25 is associated with ER restructuring. • Restructuring of the ER occurs during CLSV infection. • CLSV p25 contains 3 predicted transmembrane domains 2 of which are required for ER targeting. • Vesicles derived from the ER may be sites of CLSV replication.

The Cucumber leaf spot virus p25 auxiliary replicase protein binds and modifies the endoplasmic reticulum via N-terminal transmembrane domains

International Nuclear Information System (INIS)

Ghoshal, Kankana; Theilmann, Jane; Reade, Ron; Sanfacon, Helene; Rochon, D’Ann

2014-01-01

Cucumber leaf spot virus (CLSV) is a member of the Aureusvirus genus, family Tombusviridae. The auxiliary replicase of Tombusvirids has been found to localize to endoplasmic reticulum (ER), peroxisomes or mitochondria; however, localization of the auxiliary replicase of aureusviruses has not been determined. We have found that the auxiliary replicase of CLSV (p25) fused to GFP colocalizes with ER and that three predicted transmembrane domains (TMDs) at the N-terminus of p25 are sufficient for targeting, although the second and third TMDs play the most prominent roles. Confocal analysis of CLSV infected 16C plants shows that the ER becomes modified including the formation of punctae at connections between ER tubules and in association with the nucleus. Ultrastructural analysis shows that the cytoplasm contains numerous vesicles which are also found between the perinuclear ER and nuclear membrane. It is proposed that these vesicles correspond to modified ER used as sites for CLSV replication. - Highlights: • The CLSV p25 auxiliary replicase targets the endoplasmic reticulum (ER). • Targeting of CLSV p25 is associated with ER restructuring. • Restructuring of the ER occurs during CLSV infection. • CLSV p25 contains 3 predicted transmembrane domains 2 of which are required for ER targeting. • Vesicles derived from the ER may be sites of CLSV replication

Liver spots

Science.gov (United States)

... skin changes - liver spots; Senile or solar lentigines; Skin spots - aging; Age spots ... Liver spots are changes in skin color that occur in older skin. The coloring may be due to aging, exposure to the sun ...

Resistance of solanum species to phytophthora infestans evaluated in the detached-leaf and whole-plant assays

International Nuclear Information System (INIS)

Akhtar, K.P.; Saleem, M.Y.; Asghar, M.

2012-01-01

The reaction of 82 tomato genotypes belonging to 8 Solanum and a Lycopersicon species against Phytophthora infestans causing late blight was determined using detached-leaf and whole-plant assays. None of the test genotypes was immune or highly resistant. Of the 82 commercial and wild genotypes only TMS-2 (male-sterile and characterized by indeterminate growth) belonging to Lycopersicon esculentum was resistant with severity index of 2.4 in the detached-leaf assay on 0-5 scale (where 5 was highly susceptible) and percent disease index (%DI) of 23.3% under the whole-plant assay. Among the remaining genotypes, 41 were susceptible and 40 were highly susceptible under the detached-leaf assay, while 18 were susceptible and 63 were highly susceptible under the whole-plant assay. However, there was a significant difference in %DI for genotypes under the whole-plant assay. The response of whole-plants to inoculation with P. infestans in the detached-leaf assay was similar in all cases. The overall screening results indicate that TMS-2 is a good source of resistance and it can be useful for the development of tomato hybrid cultivars resistant to late blight. (author)

Drought resistance in early and late secondary successional species from a tropical dry forest: the interplay between xylem resistance to embolism, sapwood water storage and leaf shedding.

Science.gov (United States)

Pineda-García, Fernando; Paz, Horacio; Meinzer, Frederick C

2013-02-01

The mechanisms of drought resistance that allow plants to successfully establish at different stages of secondary succession in tropical dry forests are not well understood. We characterized mechanisms of drought resistance in early and late-successional species and tested whether risk of drought differs across sites at different successional stages, and whether early and late-successional species differ in resistance to experimentally imposed soil drought. The microenvironment in early successional sites was warmer and drier than in mature forest. Nevertheless, successional groups did not differ in resistance to soil drought. Late-successional species resisted drought through two independent mechanisms: high resistance of xylem to embolism, or reliance on high stem water storage capacity. High sapwood water reserves delayed the effects of soil drying by transiently decoupling plant and soil water status. Resistance to soil drought resulted from the interplay between variations in xylem vulnerability to embolism, reliance on sapwood water reserves and leaf area reduction, leading to a tradeoff of avoidance against tolerance of soil drought, along which successional groups were not differentiated. Overall, our data suggest that ranking species' performance under soil drought based solely on xylem resistance to embolism may be misleading, especially for species with high sapwood water storage capacity. © 2012 Blackwell Publishing Ltd.

SpotADAPT

DEFF Research Database (Denmark)

Kaulakiene, Dalia; Thomsen, Christian; Pedersen, Torben Bach

2015-01-01

by Amazon Web Services (AWS). The users aiming for the spot market are presented with many instance types placed in multiple datacenters in the world, and thus it is difficult to choose the optimal deployment. In this paper, we propose the framework SpotADAPT (Spot-Aware (re-)Deployment of Analytical...... of typical analytical workloads and real spot price traces. SpotADAPT's suggested deployments are comparable to the theoretically optimal ones, and in particular, it shows good cost benefits for the budget optimization -- on average SpotADAPT is at most 0.3% more expensive than the theoretically optimal...

Control of Late Blight of Tomato and Potato by Oilgochitosan

Directory of Open Access Journals (Sweden)

Yong Ho Choi

2011-08-01

Full Text Available Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4-linked D-glucosamine and Nacetyl- D-glucosamine. There have been many reports on the induced systemic resistance and in vivo antifungal activities of higher molecular weight chitosans with molecular weights over 3,000 amu (atomatic mass unit, but there are few papers on in vivo antifungal activities of low molecular weight chitosans (oligochitosans with molecular weights less than 3,000 amu. In our study, an oligochitosan sample (320?3,000 amu showed a potent 1-day protective activity with control values more than 94% at concentrations of 500 and 1,000 ?g/ml especially against tomato late blight caused by Phytophthora infestans under growth chamber conditions. It also displayed a moderate 1-day protective activity with control values of 67?89% at concentrations of 500 and 1,000 ?g/ml against wheat leaf rust and red pepper anthracnose. On the other hand, it showed a 16-hr curative activity against red pepper anthracnose, but not against tomato late blight and wheat leaf rust. In field experiments, oligochitosan effectively suppressed the development of late blight on potato and tomato plants with control values of 72% and 48%, respectively. The results strongly indicate that oligochitosan can be used as an eco-friendly organic material for the control of late blight on tomato and potato plants.

Cultivation and breeding of Digitalis lanata in the Netherlands

Energy Technology Data Exchange (ETDEWEB)

Mastenbroek, C.

1985-09-01

After the second world war Marshall Aid funds were used to establish a cooperative organization for growing, drying, and selling Digitalis lanata (and other medicinal, aromatic, and culinary herbs) in the Netherlands. The crop is sown in mid April and the fully mechanised harvest of the leaves takes place from September to late November. The leaves are dried for 10-12 hours at 50 degrees C maximum. The aim of breeding trials is to improve leaf production, erect leaf attitude, resistance to Septoria leaf spot and to bolting, and a higher dry matter and digoxin content.

Cutaneous manifestations of spotted fever rickettsial infections in the Central Province of Sri Lanka: a descriptive study.

Directory of Open Access Journals (Sweden)

Kosala Weerakoon

2014-09-01

Full Text Available Characteristic skin lesions play a key role in clinical diagnosis of spotted fever group rickettsioses and this study describes these cutaneous manifestations along with basic histological features.Study was conducted at Medical Unit, Teaching Hospital, Peradeniya, from November 2009 to October 2011, where a prospective data base of all rickettsial infections is maintained. Confirmation of diagnosis was made when IgM and IgG immunofluorescent antibody titre of 1/32 and >1/256 respectively. Of the 210 clinical cases, 134 had cutoff antibody titers for Rickettsia conorii antigen for confirmation. All these 134 patients had fever and skin rash, and of them 132(98% had discrete maculopapular rash while eight (6% had fern leaf type skin necrosis. Eight patients (6% had healed tick bite marks. Average size of a skin lesion was 5 mm and rash involved 52% of body surface, distributed mainly in limbs and back of the chest. Generally the facial and leg skin was slightly oedematous particularly in old aged patients. Sixteen patients (12% had pain and swelling of ankle joints where swelling extended to feet and leg. Biopsies from skin rash of six patients showed evidence of cutaneous vasculitis and of them, 247 bp region of the 17-kDa spotted fever group specific protein antigen was amplified using PCR.A discrete maculopapular rash and occasional variations such as fern leaf shape necrosis and arthritis are found in spotted fever group. Histology found vasculitis as the pathology of these lesions.

Novel insect leaf-mining after the end-Cretaceous extinction and the demise of cretaceous leaf miners, Great Plains, USA.

Directory of Open Access Journals (Sweden)

Michael P Donovan

Full Text Available Plant and associated insect-damage diversity in the western U.S.A. decreased significantly at the Cretaceous-Paleogene (K-Pg boundary and remained low until the late Paleocene. However, the Mexican Hat locality (ca. 65 Ma in southeastern Montana, with a typical, low-diversity flora, uniquely exhibits high damage diversity on nearly all its host plants, when compared to all known local and regional early Paleocene sites. The same plant species show minimal damage elsewhere during the early Paleocene. We asked whether the high insect damage diversity at Mexican Hat was more likely related to the survival of Cretaceous insects from refugia or to an influx of novel Paleocene taxa. We compared damage on 1073 leaf fossils from Mexican Hat to over 9000 terminal Cretaceous leaf fossils from the Hell Creek Formation of nearby southwestern North Dakota and to over 9000 Paleocene leaf fossils from the Fort Union Formation in North Dakota, Montana, and Wyoming. We described the entire insect-feeding ichnofauna at Mexican Hat and focused our analysis on leaf mines because they are typically host-specialized and preserve a number of diagnostic morphological characters. Nine mine damage types attributable to three of the four orders of leaf-mining insects are found at Mexican Hat, six of them so far unique to the site. We found no evidence linking any of the diverse Hell Creek mines with those found at Mexican Hat, nor for the survival of any Cretaceous leaf miners over the K-Pg boundary regionally, even on well-sampled, surviving plant families. Overall, our results strongly relate the high damage diversity on the depauperate Mexican Hat flora to an influx of novel insect herbivores during the early Paleocene, possibly caused by a transient warming event and range expansion, and indicate drastic extinction rather than survivorship of Cretaceous insect taxa from refugia.

Novel insect leaf-mining after the end-Cretaceous extinction and the demise of cretaceous leaf miners, Great Plains, USA.

Science.gov (United States)

Donovan, Michael P; Wilf, Peter; Labandeira, Conrad C; Johnson, Kirk R; Peppe, Daniel J

2014-01-01

Plant and associated insect-damage diversity in the western U.S.A. decreased significantly at the Cretaceous-Paleogene (K-Pg) boundary and remained low until the late Paleocene. However, the Mexican Hat locality (ca. 65 Ma) in southeastern Montana, with a typical, low-diversity flora, uniquely exhibits high damage diversity on nearly all its host plants, when compared to all known local and regional early Paleocene sites. The same plant species show minimal damage elsewhere during the early Paleocene. We asked whether the high insect damage diversity at Mexican Hat was more likely related to the survival of Cretaceous insects from refugia or to an influx of novel Paleocene taxa. We compared damage on 1073 leaf fossils from Mexican Hat to over 9000 terminal Cretaceous leaf fossils from the Hell Creek Formation of nearby southwestern North Dakota and to over 9000 Paleocene leaf fossils from the Fort Union Formation in North Dakota, Montana, and Wyoming. We described the entire insect-feeding ichnofauna at Mexican Hat and focused our analysis on leaf mines because they are typically host-specialized and preserve a number of diagnostic morphological characters. Nine mine damage types attributable to three of the four orders of leaf-mining insects are found at Mexican Hat, six of them so far unique to the site. We found no evidence linking any of the diverse Hell Creek mines with those found at Mexican Hat, nor for the survival of any Cretaceous leaf miners over the K-Pg boundary regionally, even on well-sampled, surviving plant families. Overall, our results strongly relate the high damage diversity on the depauperate Mexican Hat flora to an influx of novel insect herbivores during the early Paleocene, possibly caused by a transient warming event and range expansion, and indicate drastic extinction rather than survivorship of Cretaceous insect taxa from refugia.

Ozone and Botrytis interactions in onion-leaf dieback: open-top chamber studies

Energy Technology Data Exchange (ETDEWEB)

Wukasch, R.T.; Hofstra, G.

1977-09-01

Paired open-top chambers were used to study interactions between Botrytis spp. and ozone in field-grown onions. Charcoal filters removed 35 to 65% of the ambient ozone, resulting in six-fold reduction of onion leaf dieback and a 28% increase in onion yield compared with unfiltered chambers. Symptoms of leaf injury appeared soon after ozone levels exceeded 294 ..mu..g/m/sup 3/ (0.15 ppm) for 4 hr. Lesions caused by Botrytis were few because no dew formed in the chambers. However, when leaves were wetted with foggers, inoculation with mycelial suspensions of B. sauamosa in late August produced significantly more lesions and leaf dieback in the unfiltered chamber. Botrytis squamosa, B. cinerea, B. allii, and several genera of secondary fungi were isolated from these lesions. Botrytis squamosa was recovered from lesions only, whereas B. cinerea and B. allii were associated more generally with onion leaf tissue regardless of lesions. 25 references, 1 figure, 2 tables.

Beyond leaf color: Comparing camera-based phenological metrics with leaf biochemical, biophysical, and spectral properties throughout the growing season of a temperate deciduous forest

Science.gov (United States)

Yang, Xi; Tang, Jianwu; Mustard, John F.

2014-03-01

Plant phenology, a sensitive indicator of climate change, influences vegetation-atmosphere interactions by changing the carbon and water cycles from local to global scales. Camera-based phenological observations of the color changes of the vegetation canopy throughout the growing season have become popular in recent years. However, the linkages between camera phenological metrics and leaf biochemical, biophysical, and spectral properties are elusive. We measured key leaf properties including chlorophyll concentration and leaf reflectance on a weekly basis from June to November 2011 in a white oak forest on the island of Martha's Vineyard, Massachusetts, USA. Concurrently, we used a digital camera to automatically acquire daily pictures of the tree canopies. We found that there was a mismatch between the camera-based phenological metric for the canopy greenness (green chromatic coordinate, gcc) and the total chlorophyll and carotenoids concentration and leaf mass per area during late spring/early summer. The seasonal peak of gcc is approximately 20 days earlier than the peak of the total chlorophyll concentration. During the fall, both canopy and leaf redness were significantly correlated with the vegetation index for anthocyanin concentration, opening a new window to quantify vegetation senescence remotely. Satellite- and camera-based vegetation indices agreed well, suggesting that camera-based observations can be used as the ground validation for satellites. Using the high-temporal resolution dataset of leaf biochemical, biophysical, and spectral properties, our results show the strengths and potential uncertainties to use canopy color as the proxy of ecosystem functioning.

Using alfalfa leaf meal as a supplement in late-gestation beef heifer and nursing beef calf diets.

Science.gov (United States)

Zehnder, C M; Maddock, T D; DiCostanzo, A; Miller, L R; Hall, J M; Lamb, G C

2010-06-01

Two experiments were conducted to investigate using alfalfa leaf meal (ALM; 22% CP, DM basis) in beef cattle diets. In Exp. 1, a total of 24 late-gestation Angus heifers (initial BW 470 +/- 9 kg) were blocked by BW, calving date, and BCS to 1 of 4 dietary treatments in a randomized complete block design. All heifers were offered a basal hay diet (7.4% CP and 67.6% NDF, DM basis). Treatments were arranged as a 2 x 2 factorial consisting of CP supplied at 100 or 112.5% of the recommended daily intake using either soybean meal (SBM) or ALM as the supplemental protein source. Treatments were fed for an average of 100 d before calving. Total DMI was unaffected by supplemental protein source, although heifers consumed more (P Feeding 112.5% of recommended CP to heifers increased precalving rate of BW gain (P = 0.004) and DM digestibility (P = 0.003). Protein source did not affect DM digestibility (P = 0.17). Neither supplemental protein source nor protein amount affected changes in BCS or calving traits. In Exp. 2, replicates of treatments were conducted over 2 consecutive years at 2 locations in northern Minnesota to determine the effects of including ALM in creep-fed supplements on nursing calf performance, supplement BW gain efficiency (GF; BW gain over control/supplement intake), and cow performance. Treatments were control (no supplement), ALM supplement (58% ALM, as-fed basis), or a wheat middling- and soybean hull-based supplement (MIDD). Milk intake (estimated by the weigh-suckle-weigh technique) was similar among treatments. Creep-fed calves had greater (P creep feed DMI than those offered ALM (2.6 vs. 1.3 kg/d, respectively). A year x treatment interaction was noted for GF (P = 0.02). In yr 1, GF for calves offered ALM was greater (P = 0.006) than GF for calves offered MIDD, but in yr 2, there were no differences. Alfalfa leaf meal may substitute for SBM in beef heifer wintering diets and conventional creep feed ingredients. When included in creep feed diets

Impacts of Implosion Asymmetry And Hot Spot Shape On Ignition Capsules

Science.gov (United States)

Cheng, Baolian; Kwan, Thomas J. T.; Wang, Yi-Ming; Yi, S. Austin; Batha, Steve

2017-10-01

Implosion symmetry plays a critical role in achieving high areal density and internal energy at stagnation during hot spot formation in ICF capsules. Asymmetry causes hot spot irregularity and stagnation de-synchronization that results in lower temperatures and areal densities of the hot fuel. These degradations significantly affect the alpha heating process in the DT fuel as well as on the thermonuclear performance of the capsules. In this work, we explore the physical factors determining the shape of the hot spot late in the implosion and the effects of shape on Î+/-particle transport. We extend our ignition theory [1-4] to include the hot spot shape and quantify the effects of the implosion asymmetry on both the ignition criterion and capsule performance. We validate our theory with the NIF existing experimental data Our theory shows that the ignition criterion becomes more restrictive with the deformation of the hot spot. Through comparison with the NIF data, we demonstrate that the shape effects on the capsules' performance become more explicit as the self-heating and yield of the capsules increases. The degradation of the thermonuclear burn by the hot spot shape for high yield shots to date can be as high as 20%. Our theory is in good agreement with the NIF data. This work was performed under the auspices of the U.S. Department of Energy by the Los Alamos National Laboratory under Contract No. W-7405-ENG-36.

Leaf Composition of American Bur-Reed (Sparganium americanum Nutt.) to Determine Pesticide Mitigation Capability.

Science.gov (United States)

Alsharekh, Anfal; Swatzell, Lucinda J; Moore, Matthew T

2018-04-01

American bur-reed (Sparganium americanum Nutt.), a common aquatic plant in the middle and eastern United States and Canada, is often located in water-retaining drainage areas. The purpose of this study was to determine the leaf composition of S. americanum, paying attention to the cuticular waxes and the epidermis, and its ability to sorb pesticides. S. americanum leaves (n = 100) were collected in both early (June) and late (August) summer. Transverse sections of S. americanum were stained and studied with brightfield and fluorescence microscopy to estimate the structural and chemical nature of the leaf tissues cross sections. Mean total lipid content in early summer leaf samples (1.47 ± 0.83 mg mL -1 ) was significantly greater (alpha 0.05) than late summer leaves (0.15 ± 0.36 mg mL -1 ). In vitro analysis of epidermal peel permeability exposed to atrazine and malathion determined little to no sorption by the plant. Therefore, the structure of S. americanum leaves suggest this species does not have the capacity of sorbing these pesticides from runoff water.

Effects of late defoliations on chemical and sensory characteristics of cv. uva longanesi wines

OpenAIRE

Tessarin, P; Boliani, A. C; Botelho, R. V; Rusin, C; Versari, A; Parpinello, G. P; Rombolà, A. D

2014-01-01

In this study we investigated the effects of late leaf removal on the berry and wine composition and on wine sensory characteristics of Uva Longanesi, a late maturing red Italian grape variety, which wines are characterized by high levels of alcohol and excessive astringency, the latter apparently intensified by late defoliation practices. During 2008 season, spur-pruned trained vines were submitted to manual defoliation (4 basal leaves) at the onset (DEF I, 210 DOY) or at the end (DEF II, 23...

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

Science.gov (United States)

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

1998-05-01

Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf dark respiration rate (R d ) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (A max ). However, it is not known whether such scaling, if it exists, is similar among disparate biomes and plant functional types. We tested this idea by examining the interspecific relationships between R d measured at a standard temperature and leaf life-span, N, SLA and A max for 69 species from four functional groups (forbs, broad-leafed trees and shrubs, and needle-leafed conifers) in six biomes traversing the Americas: alpine tundra/subalpine forest, Colorado; cold temperate forest/grassland, Wisconsin; cool temperate forest, North Carolina; desert/shrubland, New Mexico; subtropical forest, South Carolina; and tropical rain forest, Amazonas, Venezuela. Area-based R d was positively related to area-based leaf N within functional groups and for all species pooled, but not when comparing among species within any site. At all sites, mass-based R d (R d-mass ) decreased sharply with increasing leaf life-span and was positively related to SLA and mass-based A max and leaf N (leaf N mass ). These intra-biome relationships were similar in shape and slope among sites, where in each case we compared species belonging to different plant functional groups. Significant R d-mass -N mass relationships were observed in all functional groups (pooled across sites), but the relationships differed, with higher R d at any given leaf N in functional groups (such as forbs) with higher SLA and shorter leaf life-span. Regardless of biome or functional group, R d-mass was well predicted by all combinations of leaf life-span, N mass and/or SLA (r 2 ≥ 0.79, P morphological, chemical and metabolic traits.

Leaf gas exchange of understory spruce-fir saplings in relict cloud forests, southern Appalachian Mountains, USA

Energy Technology Data Exchange (ETDEWEB)

Reinhardt, K.; Smith, W.K. [Wake Forest Univ., Winston-Salem, NC (United States). Dept. of Biology

2008-01-15

Global climate change is expected to increase regional cloud ceiling levels in many mountainous forested areas of the world. This study investigated environmental influences on the gas exchange physiology of understory red spruce and Fraser fir trees at 2 sites in the Appalachian mountains. The study hypothesized that the humid, cloudy environment would influence the photosynthetic performance of the trees, and that the species would adapt to low, diffuse light. The study also predicted that leaf conductance to carbon dioxide (CO{sub 2}) would be high as a result of low leaf-to-air-vapour pressure deficit (LAVD). The study demonstrated that leaf conductance decreased exponentially as LAVD increased. Predawn leaf water potentials remained stable, while late afternoon values declined. It was concluded that leaf gas exchange was correlated with the response of leaf conductance and LAVD. The cloudy, humid environment strongly influenced tree leaf gas exchange and water relations. It was suggested that further research is needed to investigate cloud impacts on carbon gain and water relations. 72 refs., 1 tab., 8 figs.

Leaf-IT: An Android application for measuring leaf area.

Science.gov (United States)

Schrader, Julian; Pillar, Giso; Kreft, Holger

2017-11-01

The use of plant functional traits has become increasingly popular in ecological studies because plant functional traits help to understand key ecological processes in plant species and communities. This also includes changes in diversity, inter- and intraspecific interactions, and relationships of species at different spatiotemporal scales. Leaf traits are among the most important traits as they describe key dimensions of a plant's life history strategy. Further, leaf area is a key parameter with relevance for other traits such as specific leaf area, which in turn correlates with leaf chemical composition, photosynthetic rate, leaf longevity, and carbon investment. Measuring leaf area usually involves the use of scanners and commercial software and can be difficult under field conditions. We present Leaf-IT, a new smartphone application for measuring leaf area and other trait-related areas. Leaf-IT is free, designed for scientific purposes, and runs on Android 4 or higher. We tested the precision and accuracy using objects with standardized area and compared the area measurements of real leaves with the well-established, commercial software WinFOLIA using the Altman-Bland method. Area measurements of standardized objects show that Leaf-IT measures area with high accuracy and precision. Area measurements with Leaf-IT of real leaves are comparable to those of WinFOLIA. Leaf-IT is an easy-to-use application running on a wide range of smartphones. That increases the portability and use of Leaf-IT and makes it possible to measure leaf area under field conditions typical for remote locations. Its high accuracy and precision are similar to WinFOLIA. Currently, its main limitation is margin detection of damaged leaves or complex leaf morphologies.

Palm leaves from the Late Oligocene sediments of Makum Coalfield ...

Indian Academy of Sciences (India)

Two new palm leaf impressions, cf. Iguanura wallichiana and Palmacites makumensis sp. nov. are described from the Makum Coalfield, Tinsukia District, Assam. They belong to the Tikak Parbat Formation being considered as Late Oligocene (Chattian 28–23 Myr) in age. Their presence, along with the other known fossil ...

Identification of SSR and RAPD markers linked to a resistance allele for angular leaf spot in the common bean (Phaseolus vulgaris line ESAL 550

Directory of Open Access Journals (Sweden)

Gilvan Ferreira da Silva

2003-12-01

Full Text Available The objective of this study was to identify RAPD and SSR markers associated with a resistant allele for angular leaf spot (Phaeoisariopsis griseola from the line 'ESAL 550', derived from the Andean 'Jalo EEP 558' cultivar, to assist selection of resistant genotypes. The resistant line 'ESAL 550' and the susceptible cultivar 'Carioca MG' were crossed to generate F1 and F2 populations. One hundred and twenty F2:3 families were evaluated. The DNA of the 12 most resistant families was bulked and the same was done with the DNA of the 10 most susceptible, generating two contrasting bulks. One RAPD and one SSR marker was found to be linked in coupling phase to the resistant allele. The SSR marker was amplified by the primer PV-atct001(282C, and its distance from the resistant allele was 7.6 cM. This is the most useful marker for indirect selection of resistant plants in segregating populations. The RAPD marker was amplified by the primer OPP07(857C linked in coupling phase to the resistant allele, and distant 24.4 cM. Therefore, this RAPD marker is not so useful in assisting selection because it is too far from the resistant allele.

Leaf proteome analysis of clematis chinensis: a traditional chinese medicine (tcm) by two-dimensional electrophoresis technique

International Nuclear Information System (INIS)

Ishtiaq, M.; Maqbool, M.; Hussaini, T.; Azami, S.

2014-01-01

Leaf proteome of Clematis chinensis, a traditional Chinese medicine (TCM) was analyzed by two-dimensional electrophoresis (2-DE) technique. The samples were extracted by phenol-SDS method (PSM) with high protein quantity i.e. 2.35, 0.345 mg/g (yield/dw). Proteins were visualized by staining of gels by silver stain and CBB. The gel images of each species were compared by Image Master 2D Platinum software for analytical purpose. The 2-DE profile depicted distribution of 1085 spots and out of these only 255 protein spots (23.5%) were common to all analyzed taxa. The visualized protein spots showed pI range from 3.0 to 10.0 (pH) and Mr of 7 kDa to 70 kDa. Twelve proteins were exclusively specific to C. chinensis when compared with its allies, C. finetiana and C. armandii, which may be used as biomarkers. Thirteen proteins were up-regulated in C. finetiana (0.75-0.95 fold) and twelve proteins in C. armandii (1.05-1.66 fold) whilst seven proteins down-regulated (0.66-0.94 fold) in former and three proteins (1.07-1.20 fold) in later one in comparison with C. chinensis. Twenty five differential and similar protein spots were picked and analyzed by LC-MS/MS technique. Identified proteins are related to energy metabolism (ATP synthesis), photosynthesis. environmental stimuli, regulating RNA metabolism, growth hormone regulators, evolutionary trends and gene expression. The efficiency and applicability of proteomic approach as biomarker for identification of C. chinensis is discussed in its quality control (QC) perspectives. Leaf proteins of Clematis plants are explored for the first time by 2-DE technique and debated for their metabolic role. (author)

Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest.

Science.gov (United States)

Jardine, Kolby J; Chambers, Jeffrey Q; Holm, Jennifer; Jardine, Angela B; Fontes, Clarissa G; Zorzanelli, Raquel F; Meyers, Kimberly T; de Souza, Vinicius Fernadez; Garcia, Sabrina; Gimenez, Bruno O; Piva, Luani R de O; Higuchi, Niro; Artaxo, Paulo; Martin, Scot; Manzi, Antônio O

2015-09-15

Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C₅ and C₆ GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C₆ GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

Genetic parameters and selection for resistance to bacterial spot in recombinant F6 lines of Capsicum annuum

Directory of Open Access Journals (Sweden)

Messias Gonzaga Pereira

2009-01-01

Full Text Available This study aimed to advance generations and select superior sweet pepper genotypes with resistance tobacterial spot, using the breeding method Single Seed Descent (SSD based on the segregating population derived from thecross between Capsicum annuum L. UENF 1421 (susceptible, non-pungent and UENF 1381 (resistant, pungent. Thesegregating F3 generation was grown in pots in a greenhouse until the F5 generation. The F6 generation was grown in fieldconditions. The reaction to bacterial spot was evaluated by inoculation with isolate ENA 4135 of Xanthomonas campestris pv.vesicatoria, based on a score scale and by calculating the area under the disease progress curve (AUDPC. The presence orabsence of capsaicin was also assessed. Eighteen F6 lines were bacterial leaf spot-resistant. Since no capsaicin was detectedin the F6 lines 032, 316, 399, 434, and 517, these will be used in the next steps of the sweet pepper breeding program.

Bier spots

Directory of Open Access Journals (Sweden)

Ahu Yorulmaz,

2015-10-01

Full Text Available Also called as physiologic anemic macules, Bier spots are small, hypopigmented irregularly shaped macules against a background of diffuse erythema, which creates an appearance of speckled vascular mottling of the skin. Bier spots most commonly appear on distal portions of the limbs though there are case reports describing diffuse involvement, which also affect trunk and mucous membranes of the patient. Although the exact pathophysiological mechanisms underlying Bier spots still need to be elucidated, Bier spots have been suggested to be a vascular anomaly caused by vasoconstriction of small vessels. In addition, several diseases have been proposed to be associated with Bier spots, including scleroderma renal crisis, cryoglobulinemia, Peutz-Jeghers syndrome, alopecia areata and hypoplasia of the aorta, although it has not been shown whether these associations are casual or coincidental. The clinical presentation of Bier spots is quite typical. These tiny whitish macules easily become prominent when the affected limb is placed in a dependent position and fade away when the limb is raised. Here we report a case of Bier spots in a 32-year-old male patient with characteristical clinical manifestations.

Preliminary application of tapered glass capillary microbeam in MeV-PIXE mapping of longan leaf for elemental concentration distribution analysis

Science.gov (United States)

Natyanun, S.; Unai, S.; Yu, L. D.; Tippawan, U.; Pussadee, N.

2017-09-01

This study was aimed at understanding elemental concentration distribution in local longan leaf for how the plant was affected by the environment or agricultural operation. The analysis applied the MeV-microbeam particle induced X-ray emission (PIXE) mapping technique using a home-developed tapered glass capillary microbeam system at Chiang Mai University. The microbeam was 2-MeV proton beam in 130 µm in diameter. The studying interest was in the difference in the elemental concentrations distributed between the leaf midrib and lamina areas. The micro proton beam analyzed the leaf sample across the leaf midrib edge to the leaf lamina area for total 9 data requisition spots. The resulting data were colored to form a 1D-map of the elemental concentration distribution. Seven dominant elements, Al, S, Cl, K, Ca, Sc and Fe, were identified, the first six of which were found having higher concentrations in the midrib area than in the lamina area, while the Fe concentration was in an opposite trend to that of the others.

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.

Science.gov (United States)

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

SU-E-T-510: Interplay Between Spots Sizes, Spot / Line Spacing and Motion in Spot Scanning Proton Therapy

International Nuclear Information System (INIS)

Lee, TK

2015-01-01

Purpose In proton beam configuration for spot scanning proton therapy (SSPT), one can define the spacing between spots and lines of scanning as a ratio of given spot size. If the spacing increases, the number of spots decreases which can potentially decrease scan time, and so can whole treatment time, and vice versa. However, if the spacing is too large, the uniformity of scanned field decreases. Also, the field uniformity can be affected by motion during SSPT beam delivery. In the present study, the interplay between spot/ line spacing and motion is investigated. Methods We used four Gaussian-shape spot sizes with 0.5cm, 1.0cm, 1.5cm, and 2.0cm FWHM, three spot/line spacing that creates uniform field profile which are 1/3*FWHM, σ/3*FWHM and 2/3*FWHM, and three random motion amplitudes within, +/−0.3mm, +/−0.5mm, and +/−1.0mm. We planned with 2Gy uniform single layer of 10×10cm2 and 20×20cm2 fields. Then, mean dose within 80% area of given field size, contrubuting MU per each spot assuming 1cGy/MU calibration for all spot sizes, number of spots and uniformity were calculated. Results The plans with spot/line spacing equal to or smaller than 2/3*FWHM without motion create ∼100% uniformity. However, it was found that the uniformity decreases with increased spacing, and it is more pronounced with smaller spot sizes, but is not affected by scanned field sizes. Conclusion It was found that the motion during proton beam delivery can alter the dose uniformity and the amount of alteration changes with spot size which changes with energy and spot/line spacing. Currently, robust evaluation in TPS (e.g. Eclipse system) performs range uncertainty evaluation using isocenter shift and CT calibration error. Based on presented study, it is recommended to add interplay effect evaluation to robust evaluation process. For future study, the additional interplay between the energy layers and motion is expected to present volumetric effect

Early Autumn Senescence in Red Maple (Acer rubrum L.) Is Associated with High Leaf Anthocyanin Content.

Science.gov (United States)

Anderson, Rachel; Ryser, Peter

2015-08-05

Several theories exist about the role of anthocyanins in senescing leaves. To elucidate factors contributing to variation in autumn leaf anthocyanin contents among individual trees, we analysed anthocyanins and other leaf traits in 27 individuals of red maple (Acer rubrum L.) over two growing seasons in the context of timing of leaf senescence. Red maple usually turns bright red in the autumn, but there is considerable variation among the trees. Leaf autumn anthocyanin contents were consistent between the two years of investigation. Autumn anthocyanin content strongly correlated with degree of chlorophyll degradation mid to late September, early senescing leaves having the highest concentrations of anthocyanins. It also correlated positively with leaf summer chlorophyll content and dry matter content, and negatively with specific leaf area. Time of leaf senescence and anthocyanin contents correlated with soil pH and with canopy openness. We conclude that the importance of anthocyanins in protection of leaf processes during senescence depends on the time of senescence. Rather than prolonging the growing season by enabling a delayed senescence, autumn anthocyanins in red maple in Ontario are important when senescence happens early, possibly due to the higher irradiance and greater danger of oxidative damage early in the season.

Extracellular synthesis of silver nanoparticles using the leaf extract of Coleus amboinicus Lour

Energy Technology Data Exchange (ETDEWEB)

Narayanan, Kannan Badri [Department of Biotechnology, School of Life Sciences, Pondicherry University, Kalapet, Puducherry 605014 (India); Sakthivel, Natarajan, E-mail: puns2005@gmail.com [Department of Biotechnology, School of Life Sciences, Pondicherry University, Kalapet, Puducherry 605014 (India)

2011-10-15

Highlights: {yields} Synthesis of AgNPs using the leaf extract of Coleus amboinicus L. was described. {yields} UV-vis absorption spectra showed the formation of isotrophic AgNPs at 437 nm in 6 h. {yields} XRD analysis showed intense peaks corresponding to fcc structure of AgNPs. {yields} HR-TEM analysis revealed the formation of stable anisotrophic and isotrophic AgNPs. -- Abstract: In the present investigation, Coleus amboinicus Lour. leaf extract-mediated green chemistry approach for the synthesis of silver nanoparticles was described. The nanoparticles were characterized by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The influence of leaf extract on the control of size and shape of silver nanoparticles is reported. Upon an increase in the concentration of leaf extract, there was a shift in the shape of nanoparticles from anisotrophic nanostructures like triangle, decahedral and hexagonal to isotrophic spherical nanoparticles. Crystalline nature of fcc structured nanoparticles was confirmed by XRD spectrum with peaks corresponding to (1 1 1), (2 0 0), (2 2 0) and (3 1 1) planes and bright circular spots in the selected-area electron diffraction (SAED). Such environment friendly and sustainable methods are non-toxic, cheap and alternative to hazardous chemical procedures.

Transitional–turbulent spots and turbulent–turbulent spots in boundary layers

Science.gov (United States)

Wu, Xiaohua; Moin, Parviz; Wallace, James M.; Skarda, Jinhie; Lozano-Durán, Adrián; Hickey, Jean-Pierre

2017-01-01

Two observations drawn from a thoroughly validated direct numerical simulation of the canonical spatially developing, zero-pressure gradient, smooth, flat-plate boundary layer are presented here. The first is that, for bypass transition in the narrow sense defined herein, we found that the transitional–turbulent spot inception mechanism is analogous to the secondary instability of boundary-layer natural transition, namely a spanwise vortex filament becomes a Λ vortex and then, a hairpin packet. Long streak meandering does occur but usually when a streak is infected by a nearby existing transitional–turbulent spot. Streak waviness and breakdown are, therefore, not the mechanisms for the inception of transitional–turbulent spots found here. Rather, they only facilitate the growth and spreading of existing transitional–turbulent spots. The second observation is the discovery, in the inner layer of the developed turbulent boundary layer, of what we call turbulent–turbulent spots. These turbulent–turbulent spots are dense concentrations of small-scale vortices with high swirling strength originating from hairpin packets. Although structurally quite similar to the transitional–turbulent spots, these turbulent–turbulent spots are generated locally in the fully turbulent environment, and they are persistent with a systematic variation of detection threshold level. They exert indentation, segmentation, and termination on the viscous sublayer streaks, and they coincide with local concentrations of high levels of Reynolds shear stress, enstrophy, and temperature fluctuations. The sublayer streaks seem to be passive and are often simply the rims of the indentation pockets arising from the turbulent–turbulent spots. PMID:28630304

Transitional-turbulent spots and turbulent-turbulent spots in boundary layers.

Science.gov (United States)

Wu, Xiaohua; Moin, Parviz; Wallace, James M; Skarda, Jinhie; Lozano-Durán, Adrián; Hickey, Jean-Pierre

2017-07-03

Two observations drawn from a thoroughly validated direct numerical simulation of the canonical spatially developing, zero-pressure gradient, smooth, flat-plate boundary layer are presented here. The first is that, for bypass transition in the narrow sense defined herein, we found that the transitional-turbulent spot inception mechanism is analogous to the secondary instability of boundary-layer natural transition, namely a spanwise vortex filament becomes a [Formula: see text] vortex and then, a hairpin packet. Long streak meandering does occur but usually when a streak is infected by a nearby existing transitional-turbulent spot. Streak waviness and breakdown are, therefore, not the mechanisms for the inception of transitional-turbulent spots found here. Rather, they only facilitate the growth and spreading of existing transitional-turbulent spots. The second observation is the discovery, in the inner layer of the developed turbulent boundary layer, of what we call turbulent-turbulent spots. These turbulent-turbulent spots are dense concentrations of small-scale vortices with high swirling strength originating from hairpin packets. Although structurally quite similar to the transitional-turbulent spots, these turbulent-turbulent spots are generated locally in the fully turbulent environment, and they are persistent with a systematic variation of detection threshold level. They exert indentation, segmentation, and termination on the viscous sublayer streaks, and they coincide with local concentrations of high levels of Reynolds shear stress, enstrophy, and temperature fluctuations. The sublayer streaks seem to be passive and are often simply the rims of the indentation pockets arising from the turbulent-turbulent spots.

Maize YABBY genes drooping leaf1 and drooping leaf2 affect agronomic traits by regulating leaf architecture

Science.gov (United States)

Leaf architectural traits, such as length, width and angle, directly influence canopy structure and light penetration, photosynthate production and overall yield. We discovered and characterized a maize (Zea mays) mutant with aberrant leaf architecture we named drooping leaf1 (drl1), as leaf blades ...

AY Ceti: A flaring, spotted star with a hot companion

International Nuclear Information System (INIS)

Simon, T.; Fekel, F.C. Jr.; Gibson, D.M.

1985-01-01

AY Ceti is a late-type single-line spectroscopic binary, a bright X-ray source (L/sub x/roughly-equal1.5 x 10 31 ergs s -1 ), and a spotted star, as evidenced by its prominent photometric wave. In this paper, we report on observations made with the IUE satellite and the VLA radio interferometer. The 1200--2000 A UV spectrum of AY Cet shows a hot stellar continuum and a very broad Lyα absorption line from a previously unobserved white dwarf secondary. The UV spectrum can be matched to the energy distribution of a (T/sub eff/ = 18,000 K, log g = 8) model atmosphere. Superposed on this hot continuum are high-excitation emission lines typical of chromospheres and transition regions of active late-type stars, e.g., the spotted RS CVn binaries. We conclude that the bright lines and soft X-ray emission of AY Cet arise from the cool primary star, rather than from mass transfer and accretion onto the secondary as has recently been proposed for the similar system 56 Peg. Two strong radio flares on AY Cet were observed. The second was rapidly variable and left-hand circularly polarized at levels up to π/sub c/ = 86 +- 5% at 20 cm wavelength. The most likely radio emission mechanism is an electron-cyclotron maser

Clustering and cellular distribution characteristics of virus particles of Tomato spotted wilt virus and Tomato zonate spot virus in different plant hosts.

Science.gov (United States)

Zhang, Zhongkai; Zheng, Kuanyu; Dong, Jiahong; Fang, Qi; Hong, Jian; Wang, Xifeng

2016-01-19

Tomato spotted wilt virus (TSWV) and Tomato zonate spot virus (TZSV) are the two dominant species of thrip-transmitted tospoviruses, cause significant losses in crop yield in Yunnan and its neighboring provinces in China. TSWV and TZSV belong to different serogroup of tospoviruses but induce similar symptoms in the same host plant species, which makes diagnostic difficult. We used different electron microscopy preparing methods to investigate clustering and cellular distribution of TSWV and TZSV in the host plant species. Negative staining of samples infected with TSWV and TZSV revealed that particles usually clustered in the vesicles, including single particle (SP), double particles clustering (DPC), triple particles clustering (TPC). In the immunogold labeling negative staining against proteins of TZSV, the antibodies against Gn protein were stained more strongly than the N protein. Ultrathin section and high pressure freeze (HPF)-electron microscopy preparations revealed that TSWV particles were distributed in the cisternae of endoplasmic reticulum (ER), filamentous inclusions (FI) and Golgi bodies in the mesophyll cells. The TSWV particles clustered as multiple particles clustering (MPC) and distributed in globular viroplasm or cisternae of ER in the top leaf cell. TZSV particles were distributed more abundantly in the swollen membrane of ER in the mesophyll cell than those in the phloem parenchyma cells and were not observed in the top leaf cell. However, TZSV virions were mainly present as single particle in the cytoplasm, with few clustering as MPC. In this study, we identified TSWV and TZSV particles had the distinct cellular distribution patterns in the cytoplasm from different tissues and host plants. This is the first report of specific clustering characteristics of tospoviruses particles as well as the cellular distribution of TSWV particles in the FI and globular viroplasm where as TZSV particles inside the membrane of ER. These results indicated that

A Late Cretaceous Piper (Piperaceae) from Colombia and diversification patterns for the genus.

Science.gov (United States)

Martínez, Camila; Carvalho, Mónica R; Madriñán, Santiago; Jaramillo, Carlos A

2015-02-01

Documented fossil floras in the neotropics are sparse, yet their records provide evidence on the spatial and temporal occurrence of taxa, allowing for testing of biogeographical and diversification scenarios on individual lineages. A new fossil Piper from the Late Cretaceous of Colombia is described here, and its importance for assessing diversification patterns in the genus is addressed. Leaf architecture of 32 fossil leaf compressions from the Guaduas Formation was compared with that of 294 extant angiosperm species. The phylogenetic position of the fossil named Piper margaritae sp. nov. was established based on leaf traits and a molecular scaffold of Piper. The age of the fossil was independently used as a calibration point for divergence time estimations. Natural affinities of P. margaritae to the Schilleria clade of Piper indicate that the genus occurred in tropical America by the Late Cretaceous. Estimates of age divergence and lineage accumulation reveal that most of the extant diversity of the genus accrued during the last ∼30 Myr. The recent radiation of Piper is coeval with both the Andean uplift and the emergence of Central America, which have been proposed as important drivers of diversity. This pattern could exemplify a recurrent theme among many neotropical plant lineages. © 2015 Botanical Society of America, Inc.

Spotted inflation

International Nuclear Information System (INIS)

Matsuda, Tomohiro

2010-01-01

We describe new scenarios for generating curvature perturbations when inflaton (curvaton) has significant interactions. We consider a ''spot'', which arises from interactions associated with an enhanced symmetric point (ESP) on the trajectory. Our first example uses the spot to induce a gap in the field equation. We observe that the gap in the field equation may cause generation of curvature perturbation if it does not appear simultaneous in space. The mechanism is similar to the scenario of inhomogeneous phase transition. Then we observe that the spot interactions may initiate warm inflation in the cold Universe. Creation of cosmological perturbation is discussed in relation to the inflaton dynamics and the modulation associated with the spot interactions

Geographical distribution of myrothecium leaf spot disease of momordica charantial L. caused by myrothecium roridum tode in agro-ecological zone of punjab, Pakistan

International Nuclear Information System (INIS)

Din, G. M.; Farooq, S.; Khan, S. N.; Imani, J.; Naz, S.

2017-01-01

A series of field surveys were carried out during July-October 2012-14 for the development of disease distribution map and updating the index of Myrothecium leaf spot of Momordica charantia (Bitter gourd) in Punjab province. A total of 29 districts were surveyed belonging to 9 sub agro ecological zones of Punjab. The index was calculated on the basis of incidence, prevalence and severity of the disease. The information from stakeholders was gathered through field scouting, formal and informal discussions. Data on socioeconomics was collected by a structured questionnaire. The symptomatic plants and soil specimens were collected form diseased field and transferred to lab for onward studies on host-pathogen characterization and management. Infection development on the plant was investigated on a (0-5) visual severity rating scale. Fungus was isolated, identified on morphological and molecular characteristics as Myrothecium roridum and cultures were deposited to First Fungal Culture Bank of Pakistan (Accession No. FCBP 1155) and Leibniz-institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Germany (Accession No. DSM 28971). Data gathered highlighted dominance of the disease in mixed cropping zone of Punjab province. Highest disease index (31%) was recorded in mixed cropping zone and lowest (3%) in D.G khan zone. However its severity may vary due to adopted cultural and chemical practices by individual farmers. The investigations strengthen the involvement of irrigation technique, soil type and cropping history in introduction and sporadic occurrence of the disease. (author)

Variation in the Level of Grain Defect Light Flecks and Spots on Cattle Hides

Science.gov (United States)

Nafstad, O; Grønstøl, H

2001-01-01

The occurrence of hide damage light flecks and spots was determined on tanned hides from 28 herds during a period of 8 to 12 months. Light flecks and spots are described as small areas of grain loss up to 3 mm in diameter that are seen on dyed crust cattle leather. Damage was found on 75.8% of all hides. The neck and shoulders were the anatomical region with the highest prevalence of damage. Sixty-eight per cent of all hides had light flecks and spots in this region. The forelimbs and dewlap were the anatomical region with the second highest occurrence with a prevalence of 39.1%. This distribution corresponded to the known distribution of lice in cattle. No significant differences were observed in age, sex, prevalence of lice in the herd assessed in March or infestations with different lice species. The frequency of light flecks and spots varied significantly during the year. The frequency was highest in the late winter and early spring, decreased significantly during the summer and was lowest in the autumn. This variation supported the importance of lice in the development of light flecks and spots and suggested a relatively long healing period for the damages induced by lice. PMID:11455905

Spot Weight Adaptation for Moving Target in Spot Scanning Proton Therapy.

Science.gov (United States)

Morel, Paul; Wu, Xiaodong; Blin, Guillaume; Vialette, Stéphane; Flynn, Ryan; Hyer, Daniel; Wang, Dongxu

2015-01-01

This study describes a real-time spot weight adaptation method in spot-scanning proton therapy for moving target or moving patient, so that the resultant dose distribution closely matches the planned dose distribution. The method proposed in this study adapts the weight (MU) of the delivering pencil beam to that of the target spot; it will actually hit during patient/target motion. The target spot that a certain delivering pencil beam may hit relies on patient monitoring and/or motion modeling using four-dimensional (4D) CT. After the adapted delivery, the required total weight [Monitor Unit (MU)] for this target spot is then subtracted from the planned value. With continuous patient motion and continuous spot scanning, the planned doses to all target spots will eventually be all fulfilled. In a proof-of-principle test, a lung case was presented with realistic temporal and motion parameters; the resultant dose distribution using spot weight adaptation was compared to that without using this method. The impact of the real-time patient/target position tracking or prediction was also investigated. For moderate motion (i.e., mean amplitude 0.5 cm), D95% to the planning target volume (PTV) was only 81.5% of the prescription (RX) dose; with spot weight adaptation PTV D95% achieves 97.7% RX. For large motion amplitude (i.e., 1.5 cm), without spot weight adaptation PTV D95% is only 42.9% of RX; with spot weight adaptation, PTV D95% achieves 97.7% RX. Larger errors in patient/target position tracking or prediction led to worse final target coverage; an error of 3 mm or smaller in patient/target position tracking is preferred. The proposed spot weight adaptation method was able to deliver the planned dose distribution and maintain target coverage when patient motion was involved. The successful implementation of this method would rely on accurate monitoring or prediction of patient/target motion.

Spot Weight Adaptation for Moving Target in Spot Scanning Proton Therapy

Directory of Open Access Journals (Sweden)

Paul eMorel

2015-05-01

Full Text Available Purpose: This study describes a real-time spot weight adaptation method in spot-scanning proton therapy for moving target or moving patient, so that the resultant dose distribution closely matches the planned dose distribution. Materials and Methods: The method proposed in this study adapts the weight (MU of the delivering pencil beam to that of the target spot it will actually hit during patient/target motion. The target spot a certain delivering pencil beam may hit relies on patient monitoring and/or motion modeling using four-dimensional (4D CT. After the adapted delivery, the required total weight (MU for this target spot is then subtracted from the planned value. With continuous patient motion and continuous spot scanning, the planned doses to all target spots will eventually be all fulfilled. In a proof-of-principle test, a lung case was presented with realistic temporal and motion parameters; the resultant dose distribution using spot weight adaptation was compared to that without using this method. The impact of the real-time patient/target position tracking or prediction was also investigated.Results: For moderate motion (i.e., mean amplitude 0.5 cm, D95% to the planning target volume (PTV was only 81.5% of the prescription (RX dose; with spot weight adaptation PTV D95% achieves 97.7%RX. For large motion amplitude (i.e., 1.5 cm, without spot weight adaptation PTV D95% is only 42.9% of RX; with spot weight adaptation, PTV D95% achieves 97.7%RX. Larger errors in patient/target position tracking or prediction led to worse final target coverage; an error of 3mm or smaller in patient/target position tracking is preferred. Conclusion: The proposed spot weight adaptation method was able to deliver the planned dose distribution and maintain target coverage when patient motion was involved. The successful implementation of this method would rely on accurate monitoring or prediction of patient/target motion.

Bier spots

OpenAIRE

Ahu Yorulmaz,; Seray Kulcu Cakmak; Esra Ar?; Ferda Artuz

2015-01-01

Also called as physiologic anemic macules, Bier spots are small, hypopigmented irregularly shaped macules against a background of diffuse erythema, which creates an appearance of speckled vascular mottling of the skin. Bier spots most commonly appear on distal portions of the limbs though there are case reports describing diffuse involvement, which also affect trunk and mucous membranes of the patient. Although the exact pathophysiological mechanisms underlying Bier spots still need to be elu...

Topography and crop management are key factors for the development of american leaf spot epidemics on coffee in costa rica.

Science.gov (United States)

Avelino, Jacques; Cabut, Sandrine; Barboza, Bernardo; Barquero, Miguel; Alfaro, Ronny; Esquivel, César; Durand, Jean-François; Cilas, Christian

2007-12-01

ABSTRACT We monitored the development of American leaf spot of coffee, a disease caused by the gemmiferous fungus Mycena citricolor, in 57 plots in Costa Rica for 1 or 2 years in order to gain a clearer understanding of conditions conducive to the disease and improve its control. During the investigation, characteristics of the coffee trees, crop management, and the environment were recorded. For the analyses, we used partial least-squares regression via the spline functions (PLSS), which is a nonlinear extension to partial least-squares regression (PLS). The fungus developed well in areas located between approximately 1,100 and 1,550 m above sea level. Slopes were conducive to its development, but eastern-facing slopes were less affected than the others, probably because they were more exposed to sunlight, especially in the rainy season. The distance between planting rows, the shade percentage, coffee tree height, the type of shade, and the pruning system explained disease intensity due to their effects on coffee tree shading and, possibly, on the humidity conditions in the plot. Forest trees and fruit trees intercropped with coffee provided particularly propitious conditions. Apparently, fertilization was unfavorable for the disease, probably due to dilution phenomena associated with faster coffee tree growth. Finally, series of wet spells interspersed with dry spells, which were frequent in the middle of the rainy season, were critical for the disease, probably because they affected the production and release of gemmae and their viability. These results could be used to draw up a map of epidemic risks taking topographical factors into account. To reduce those risks and improve chemical control, our results suggested that farmers should space planting rows further apart, maintain light shading in the plantation, and prune their coffee trees.

Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

Science.gov (United States)

Taira, Wataru; Otaki, Joji M

2016-01-01

Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

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Wataru Taira

Full Text Available Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

Alternaria Leaf Spot on Mealycup Sage (Salvia farinacea Benth.) Caused by Alternaria alternata (Fr.) Keissler

OpenAIRE

Hiromitsu, NEGISHI; Kazuo, SUYAMA; Faculty of Agriculture,Tokyo University of Agriculture; Faculty of Agriculture,Tokyo University of Agriculture

2002-01-01

In June 1995, a disease causing round to irregular-shaped, water-soaked, brown to blackish brown spots on mealycup sage (Salvia farinacea Benth.) was found in Atsugi-shi, Kanagawa Prefecture, Japan. The symptoms were seen only on leaves, not on neither flower petals or stems. The disease was also found in Setagaya-ku, Tokyo, Memambetsu-cho, Hokkaido and Shimoda-shi and Matsuzaki-cho, Shizuoka. An Alternaria sp. was frequently isolated from these diseased plants. The isolates were severely pat...

Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints

International Nuclear Information System (INIS)

Hassanifard, Soran; Zehsaz, Mohammad; Esmaeili, Firooz

2011-01-01

In the present study, the effects of spot weld arrangements in multi-spot welded joints on the fatigue behavior of the joints are studied. Three different four-spot welded joints are considered: one-row four-spot parallel to the loading direction, one-row four-spot perpendicular to the loading direction and two-row four-spot weld specimens. The experimental fatigue test results reveal that the differences between the fatigue lives of three spot welded types in the low cycle regime are more considerable than those in the high cycle regime. However, all kinds of spot weld specimens have similar fatigue strength when approaching a million cycles. A non-linear finite element analysis is performed to obtain the relative stress gradients, effective distances and notch strength reduction factors based on the volumetric approach. The work here shows that the volumetric approach does a very good job in predicting the fatigue life of the multi-spot welded joints

Energy is not Coffee. An assessment of blind spots on energy spot-markets

International Nuclear Information System (INIS)

Jepma, C.J.; Spijker, E.; Van der Gaast, W.; De Jong, F.; Overmars, P.

2006-01-01

This study was to be the first in a series of studies on the title subject. It specifically focuses on the differences and similarities with a number of other spot-markets and aims to frame the energy spot markets and their potential development into a broader perspective. Main conclusion is that energy spot-markets differ from several other physical and non-physical spot-markets in many ways. This implies that 'perfect' energy spot-markets may inherently be (much) less perfect than other spot-markets that have approximated the stage of theoretical perfection

"Breath figures" on leaf surfaces-formation and effects of microscopic leaf wetness.

Science.gov (United States)

Burkhardt, Juergen; Hunsche, Mauricio

2013-01-01

"Microscopic leaf wetness" means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 μm, microscopic leaf wetness is about two orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the type and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g., ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

Cellular protein receptors of maculosin, a host specific phytotoxin of spotted knapweed (Centaurea maculosa L.).

Science.gov (United States)

Park, S H; Strobel, G A

1994-01-05

Maculosin (the diketopiperazine, cyclo (L-Pro-L-Tyr)) is a host specific phytotoxin produced by Alternaria alternata on spotted knapweed (Centaurea maculosa L.). Receptors for this phytotoxin have been isolated from spotted knapweed. Knapweed leaves possess most of the maculosin-binding activity in the cytosolic fraction. However, activity was also observed in the whole membrane fraction of the leaf. The binding component of the cytosolic fraction was identified as a protein(s) because of its heat-lability and sensitivity to proteases. A 16-fold purification of a toxin-binding protein was carried out by ammonium sulfate fractionation, and Sephadex G-200, and maculosin-affinity column chromatography. The affinity column was prepared with epoxy activated Sepharose 6B to which the phenolic group of maculosin was attached. The receptor was estimated to contain more than one binding protein by native and SDS-PAGE. At least one of the maculosin-binding proteins was identified as ribulose-1,5-biphosphate carboxylase (RuBPcase).

Effect of Plant Growth Regulators on Leaf Number, Leaf Area and Leaf Dry Matter in Grape

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Zahoor Ahmad BHAT

2011-03-01

Full Text Available Influence of phenylureas (CPPU and brassinosteriod (BR along with GA (gibberellic acid were studied on seedless grape vegetative characteristics like leaf number, leaf area and leaf dry matter. Growth regulators were sprayed on the vines either once (7 days after fruit set or 15 days after fruit set or twice (7+15 days after fruit set. CPPU 2 ppm+BR 0.4 ppm+GA 25 ppm produced maximum number of leaves (18.78 while as untreated vines produced least leaf number (16.22 per shoot. Maximum leaf area (129.70 cm2 and dry matter content (26.51% was obtained with higher CPPU (3 ppm and BR (0.4 ppm combination along with GA 25 ppm. Plant growth regulators whether naturally derived or synthetic are used to improve the productivity and quality of grapes. The relatively high value of grapes justifies more expensive inputs. A relatively small improvement in yield or fruit quality can justify the field application of a very costly product. Application of new generation growth regulators like brassinosteroids and phenylureas like CPPU have been reported to increase the leaf number as well as leaf area and dry matter thereby indirectly influencing the fruit yield and quality in grapes.

High-resolution mapping and characterization of qRgls2, a major quantitative trait locus involved in maize resistance to gray leaf spot.

Science.gov (United States)

Xu, Ling; Zhang, Yan; Shao, Siquan; Chen, Wei; Tan, Jing; Zhu, Mang; Zhong, Tao; Fan, Xingming; Xu, Mingliang

2014-08-31

Gray leaf spot (GLS) caused by Cercospora zeae-maydis (Czm) or Cercospora zeina (Cz) is a devastating maize disease and results in substantial yield reductions worldwide. GLS resistance is a quantitatively inherited trait. The development and cultivation of GLS-resistant maize hybrids are the most cost-effective and efficient ways to control this disease. We previously detected a major GLS resistance QTL, qRgls2, in bin 5.03-04, which spans the whole centromere of chromosome 5 encompassing a physical distance of ~110-Mb. With advanced backcross populations derived from the cross between the resistant Y32 and susceptible Q11 inbred lines, a sequential recombinant-derived progeny testing strategy was adapted to fine map qRgls2. We narrowed the region of qRgls2 from an initial ~110-Mb to an interval of ~1-Mb, flanked by the markers G346 and DD11. qRgls2 showed predominantly additive genetic effects and significantly increased the resistance percentage by 20.6 to 24.6% across multiple generations. A total of 15 genes were predicted in the mapped region according to the 5b.60 annotation of the maize B73 genome v2. Two pieces of the mapped qRgls2 region shared collinearity with two distant segments on maize chromosome 4. qRgls2, a major QTL involved in GLS resistance, was mapped to a ~1-Mb region close to the centromere of chromosome 5. There are 15 predicted genes in the mapped region. It is assumed that qRgls2 could be widely used to improve maize resistance to GLS.

Tanggap Genotipe Kacang Tanah Terhadap Penyakit Bercak Daun Cercospora dan Karat Daun Puccinia

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Alfi Inayati

2016-03-01

Full Text Available Leaf spot and rust are two important diseases on groundnut. Both diseases are frequently found at the same time that influence the growth and reduce the yield of groundnut. This study was conducted to evaluate thirteen groundnut genotypes resistance to leaf spot and rust disease.  The experiment was conducted using a split plot design and three replications, with inoculated and uninoculated treatment as main plot, and  groundnut genotypes as the sub plot.  Disease assessment was conducted by counting number of pustules per leaf, the number of spots per leaf, rust disease intensity, the intensity of leaf spot disease, and leaf area index. Yield components including stover weight, number of pods per plant, number of empty pods, number of chipo pods, and weight of pods per plant were recorded for both inoculated and uninoculated plants. The result showed that leaf spot disease developed earlier than rust disease. Only one genotype was susceptible to rust and the other 12 genotypes were very susceptible, whereas all genotypes tested were very susceptible to leaf spot. The intensity of rust and leaf spot diseases was negatively correlated with yield (r = - 0.1 – (0.4. Rust and leaf spot diseases reduced the yield components including stover weight (73.2%, number of pods (68%, and weight of pods (72.5%. The number of empty pods and chipo pods were increase to 81% and 56.4% respectively. 

Transcriptome Analysis of Poplar during Leaf Spot Infection with Sphaerulina spp.

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Adam J Foster

Full Text Available Diseases of poplar caused by the native fungal pathogen Sphaerulina musiva and related species are of growing concern, particularly with the increasing interest in intensive poplar plantations to meet growing energy demands. Sphaerulina musiva is able to cause infection on leaves, resulting in defoliation and canker formation on stems. To gain a greater understanding of the different responses of poplar species to infection caused by the naturally co-evolved Sphaerulina species, RNA-seq was conducted on leaves of Populus deltoides, P. balsamifera and P. tremuloides infected with S. musiva, S. populicola and a new undescribed species, Ston1, respectively. The experiment was designed to contain the pathogen in a laboratory environment, while replicating disease development in commercial plantations. Following inoculation, trees were monitored for disease symptoms, pathogen growth and host responses. Genes involved in phenylpropanoid, terpenoid and flavonoid biosynthesis were generally upregulated in P. balsamifera and P. tremuloides, while cell wall modification appears to play an important role in the defense of P. deltoides. Poplar defensive genes were expressed early in P. balsamifera and P. tremuloides, but their expression was delayed in P. deltoides, which correlated with the rate of disease symptoms development. Also, severe infection in P. balsamifera led to leaf abscission. This data gives an insight into the large differences in timing and expression of genes between poplar species being attacked by their associated Sphaerulina pathogen.

Effects of drought on leaf gas exchange in an eastern broadleaf deciduous forest

Science.gov (United States)

Roman, D. T.; Brzostek, E. R.; Dragoni, D.; Rahman, A. F.; Novick, K. A.; Phillips, R.

2013-12-01

Understanding plant physiological adaptations to drought is critical for predicting changes in ecosystem productivity that result from climate variability and future climate change. From 2011-2013, southern Indiana experienced a late growing season drought in 2011, a severe early season drought in 2012, and a wet growing season in 2013 characterized by an absence of water stress with frequent precipitation and milder temperatures. The 2012 drought was unique due to the severity and early onset drought conditions (compared to the more frequent late season drought) and was characterized by a Palmer Drought severity index below -4 and precipitation totals from May - July that were 70% less than the long-term (2000 - 2010) mean. During the 2012 drought, an 11% decline in net ecosystem productivity relative to the long-term mean was observed at the AmeriFlux tower in Morgan Monroe State Forest despite a growing season that started ~25 days earlier. Thus, the objective of this study is to evaluate species-specific contributions to the canopy-scale response to inter-annual variability in water stress. We investigated differences between tree species in their response to climate variability using weekly leaf gas exchange and leaf water potential measurements during the growing seasons of 2011-2013. We used this unique dataset, collected at the top of the canopy with a 25 m boom lift, to evaluate changes in leaf water status and maximum assimilation capacity in the drought versus non-drought years. The leaf-level physiology of oak (Quercus) species appears to be less sensitive to drought than other species (tulip poplar [Liriodendron tulipifera], sassafras [Sassafras albidum] and sugar maple [Acer saccharum]). Preliminary data shows mean canopy leaf water potential for oaks was 30.5% more negative in May-July 2012 versus the same time period in 2013. During these same periods the rate of C assimilation in oaks was reduced by only 3%, whereas other species were reduced by

Why do leaf-tying caterpillars abandon their leaf ties?

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Michelle Sliwinski

2013-09-01

Full Text Available 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

Histamine release inhibitory activity of Piper nigrum leaf.

Science.gov (United States)

Hirata, Noriko; Naruto, Shunsuke; Inaba, Kazunori; Itoh, Kimihisa; Tokunaga, Masashi; Iinuma, Munekazu; Matsuda, Hideaki

2008-10-01

Oral administration of a methanolic extract of Piper nigrum leaf (PN-ext, 50, 200 and 500 mg/kg) showed a potent dose-dependent inhibition of dinitrofluorobenzene (DNFB)-induced cutaneous reaction at 1 h [immediate phase response (IPR)] after and 24 h [late phase response (LPR)] after DNFB challenge in mice which were passively sensitized with anti-dinitrophenyl (DNP) IgE antibody. Ear swelling inhibitory effect of PN-ext (50, 200 and 500 mg/kg, per os (p.o.)) on very late phase response (vLPR) in the model mice was significant but weaker than that on IPR. Oral administration of PN-ext (50, 200 and 500 mg/kg for 7 d) inhibited picryl chloride (PC)-induced ear swelling in PC sensitized mice. PN-ext exhibited in vitro inhibitory effect on compound 48/80-induced histamine release from rat peritoneal mast cells. Two lignans of PN-ext, (-)-cubebin (1) and (-)-3,4-dimethoxy-3,4-desmethylenedioxycubebin (2), were identified as major active principles having histamine release inhibitory activity.

Symptoms of main Callistephus chinensis L. Nees. diseases under Ukrainian urban ecosystem conditions of the forest-steppe zone

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Marchenko Alla

2017-12-01

Full Text Available Phytopathological monitoring of C. chinensis (L. Nees. has proven withering and root rot to be the dominating diseases in agrobiocenoses under Ukrainian urban ecosystem conditions of the forest-steppe zone. Their spread was 5,1 and 4 times more than one of spotting. The complex of plant pathogenic overground and underground microflora consists of 24 causative agents. B. cinerea, F. oxysporum, V. albo-atrum have been found on all the vegetative and reproductive parts of Callistephus chinensis (L. Nees., , Ph. cactorum – on plant overground and underground parts, Rh. solani – on underground parts and seeds, A. zinniae – on overground parts and seeds. The main C. chinensis (L. Nees. disease symptoms have been diagnosed (leaf spots, powdery mildew, verticillium wilt, rust, ramularia spot, septoria spots, botrytis blight, grey mold rot, late blight, fusarium blight, black stem.

Rocky Mountain spotted fever

Science.gov (United States)

... spotted fever on the foot Rocky Mountain spotted fever, petechial rash Antibodies Deer and dog tick References McElligott SC, Kihiczak GG, Schwartz RA. Rocky Mountain spotted fever and other rickettsial infections. In: Lebwohl MG, Heymann ...

Simultaneous measurement of 25 inflammatory markers and neurotrophins in neonatal dried blood spots by immunoassay with xMAP technology

DEFF Research Database (Denmark)

Skogstrand, Kristin; Thorsen, Poul; Nørgaard-Pedersen, Bent

2005-01-01

BACKGROUND: Inflammatory reactions and other events in early life may be part of the etiology of late-onset diseases, including cerebral palsy, autism, and type 1 diabetes. Most neonatal screening programs for congenital disorders are based on analysis of dried blood spot samples (DBSS), and stor...

The Spotting Distribution of Wildfires

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Jonathan Martin

2016-06-01

Full Text Available In wildfire science, spotting refers to non-local creation of new fires, due to downwind ignition of brands launched from a primary fire. Spotting is often mentioned as being one of the most difficult problems for wildfire management, because of its unpredictable nature. Since spotting is a stochastic process, it makes sense to talk about a probability distribution for spotting, which we call the spotting distribution. Given a location ahead of the fire front, we would like to know how likely is it to observe a spot fire at that location in the next few minutes. The aim of this paper is to introduce a detailed procedure to find the spotting distribution. Most prior modelling has focused on the maximum spotting distance, or on physical subprocesses. We will use mathematical modelling, which is based on detailed physical processes, to derive a spotting distribution. We discuss the use and measurement of this spotting distribution in fire spread, fire management and fire breaching. The appendix of this paper contains a comprehensive review of the relevant underlying physical sub-processes of fire plumes, launching fire brands, wind transport, falling and terminal velocity, combustion during transport, and ignition upon landing.

Symptom and Resistance of Cultivated and Wild Capsicum Accessions to Tomato Spotted Wilt Virus

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Jung-Heon Han

2011-04-01

Full Text Available One hundred Capsicum accessions were screened for symptomatic response and resistance to Tomato spotted wilt virus-pb1 (TSWV-pb1. Symptom and its severity rating were checked by visual observation at 9, 12, 14, and 45 days after inoculation, respectively. Enzyme-linked immune-sorbent assay was performed all tested individuals on non-inoculated upper leaves after the third rating to indentify viral infection. Leaf curling was predominant in almost susceptible individuals of each accession. Stem necrosis was most frequent in wild species while yellowing in commercial hybrids and Korean land race cultivars. Ring spot, a typical symptom of TSWV, was rarely detected in some of a few accessions. Different levels of resistance to TSWV-pb1 were observed among the tested accessions. High level of resistance was detected in 4 commercial cultivars of Kpc- 35, -36, -57, and -62, and 8 wild species of PBI-11, C00105, PBC076, PBC280, PBC426, PBC495, PBC537, and PI201238 through seedling test by mechanical inoculation.

Relationship between hot spot residues and ligand binding hot spots in protein-protein interfaces.

Science.gov (United States)

Zerbe, Brandon S; Hall, David R; Vajda, Sandor; Whitty, Adrian; Kozakov, Dima

2012-08-27

In the context of protein-protein interactions, the term "hot spot" refers to a residue or cluster of residues that makes a major contribution to the binding free energy, as determined by alanine scanning mutagenesis. In contrast, in pharmaceutical research, a hot spot is a site on a target protein that has high propensity for ligand binding and hence is potentially important for drug discovery. Here we examine the relationship between these two hot spot concepts by comparing alanine scanning data for a set of 15 proteins with results from mapping the protein surfaces for sites that can bind fragment-sized small molecules. We find the two types of hot spots are largely complementary; the residues protruding into hot spot regions identified by computational mapping or experimental fragment screening are almost always themselves hot spot residues as defined by alanine scanning experiments. Conversely, a residue that is found by alanine scanning to contribute little to binding rarely interacts with hot spot regions on the partner protein identified by fragment mapping. In spite of the strong correlation between the two hot spot concepts, they fundamentally differ, however. In particular, while identification of a hot spot by alanine scanning establishes the potential to generate substantial interaction energy with a binding partner, there are additional topological requirements to be a hot spot for small molecule binding. Hence, only a minority of hot spots identified by alanine scanning represent sites that are potentially useful for small inhibitor binding, and it is this subset that is identified by experimental or computational fragment screening.

Fungicide Efficacy in Peach Rusty Spot Control in Serbia

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Nenad Dolovac

2010-01-01

Full Text Available Rusty Spot has long been known as a harmful peach disease in many parts of the world. During the past several years, rusty spot infection of the late-maturing peach cultivars (Summerset, Suncrest, Fayette and O’Henry caused significant yield losses in Serbia.Although the etiology of the disease is still unknown, there are numerous studies attempting to set a strategy for its control and recommend appropriate chemical and other peach protection methods. However, because of specific environmental conditions in Serbia, recommended protection method using repeated fungicide treatments, starting from petal fall, did not prove to be efficient and the rate of infection in some susceptible peach cultivars reached 100%. In 2003 and 2004 a field trial was conducted in order to test the efficacy of fungicides (a.i. kresoxim-methyl, flusilazole and sulfur for the efficient control of Rusty Spot epidemics. The trial was carried out under conditions of natural infection on the peach cv. Summerset at the locality of Bela Crkva, Serbia. In the ntreated control plots,high disease incidence was recorded with the percentage of affected fruit surface ranging from 33.5% in the first, up to the 35.4% in the second year of the trail. Among fungicides included in the trial, kresoxim-methyl proved to be the most efficient (90.25% in the first and 91.12% in the second year of the trial, flusilazole exhibited lower efficacy (87.28% and 80.61%, respectively while sulfur was the least efficient 82.33% and 80.30%, respectively. Determination of the most efficient fungicide for the peach rusty spot control in Serbia provides basic nformation for further investigations which will include optimization of treatment terms, as well as additional agro-technical control measures.

SPOT Program

Science.gov (United States)

Smith, Jason T.; Welsh, Sam J.; Farinetti, Antonio L.; Wegner, Tim; Blakeslee, James; Deboeck, Toni F.; Dyer, Daniel; Corley, Bryan M.; Ollivierre, Jarmaine; Kramer, Leonard;

Modelo agrometeorológico regional para estimativa da severidade da mancha de Phaeosphaeria em milho safrinha no Estado de São Paulo, Brasil Regional agrometeorological model to estimate Phaeosphaeria leaf spot severity on off-season maize crop in the State of São Paulo, Brazil

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Glauco de Souza Rolim

2007-01-01

Full Text Available O milho safrinha, cultivado no outono-inverno, no Estado de São Paulo, tem apresentado com freqüência significativas reduções de produtividade devidas à mancha foliar de Phaeosphaeria. Como estratégia para minimizar esses danos, os modelos agrometeorológicos de previsão de doenças podem auxiliar no planejamento e na tomada de decisões para o controle da doença na cultura. Dessa forma, este trabalho tem como objetivo o desenvolvimento e teste de modelos agrometeorológicos para previsão da porcentagem da área foliar afetada pela doença (%AFA em função do acúmulo diário de temperatura média e de chuva, em escala regional. Para tanto, foram utilizadas informações sobre a severidade da mancha de Phaeosphaeria em 158 cultivares de milho com diferentes níveis de resistência, durante a safrinha, em 14 diferentes localidades do Estado de São Paulo. Modelos foram desenvolvidos para cultivares suscetíveis, moderadamente resistentes e resistentes e os resultados indicaram haver boa performance na estimativa da %AFA, com altos valores de coeficiente de determinação (0,92; 0,81 e 0,83 respectivamente e índice de concordância de Willmott (0,98; 0,87; 0,94 respectivamente, além de teste F significativo a 1% de probabilidade para todos os casos. Os resultados também permitiram sugerir que a chuva e a temperatura são os fatores preponderantes para a ocorrência da mancha de Phaeosphaeria no Estado de São Paulo. Esses modelos têm a vantagem de utilizar variáveis usualmente obtidas em estações meteorológicas e poderão ser empregados em sistemas de alerta fitossanitários para monitoramento da doença no Estado.The off-season maize crop (named as "Safrinha" has been frequently suffering significant yield losses due to Phaeosphaeria leaf spot in state of São Paulo, Brazil. As a strategy for minimizing these losses, agrometeorological disease forecasting models can help in the planning and decision-making for disease control

Can Leaf Spectroscopy Predict Leaf and Forest Traits Along a Peruvian Tropical Forest Elevation Gradient?

Science.gov (United States)

Doughty, Christopher E.; Santos-Andrade, P. E.; Goldsmith, G. R.; Blonder, B.; Shenkin, A.; Bentley, L. P.; Chavana-Bryant, C.; Huaraca-Huasco, W.; Díaz, S.; Salinas, N.; Enquist, B. J.; Martin, R.; Asner, G. P.; Malhi, Y.

2017-11-01

High-resolution spectroscopy can be used to measure leaf chemical and structural traits. Such leaf traits are often highly correlated to other traits, such as photosynthesis, through the leaf economics spectrum. We measured VNIR (visible-near infrared) leaf reflectance (400-1,075 nm) of sunlit and shaded leaves in 150 dominant species across ten, 1 ha plots along a 3,300 m elevation gradient in Peru (on 4,284 individual leaves). We used partial least squares (PLS) regression to compare leaf reflectance to chemical traits, such as nitrogen and phosphorus, structural traits, including leaf mass per area (LMA), branch wood density and leaf venation, and "higher-level" traits such as leaf photosynthetic capacity, leaf water repellency, and woody growth rates. Empirical models using leaf reflectance predicted leaf N and LMA (r2 > 30% and %RMSE < 30%), weakly predicted leaf venation, photosynthesis, and branch density (r2 between 10 and 35% and %RMSE between 10% and 65%), and did not predict leaf water repellency or woody growth rates (r2<5%). Prediction of higher-level traits such as photosynthesis and branch density is likely due to these traits correlations with LMA, a trait readily predicted with leaf spectroscopy.

Models of spots and flares

International Nuclear Information System (INIS)

Mullan, D.J.

1983-01-01

Laboratory experiments in recent years have shown that there are many more ways to drive a plasma out of equilibrium than to preserve equilibrium. In that sense, it is perhaps easier to understand why flares should occur in a stellar atmosphere than why a long-lived feature such as a dark spot should persist. The author summarizes work on the equilibrium structure of cool spots in the sun and stars. Since spots involve complex interactions between convective flows and magnetic fields, he needs to refer to observations for help in identifying the dominant processes which should enter into the modelling. His summary therefore begins by discussing certain relevant properties of spots in the solar atmosphere. The next sections deal with the magnetic fields in spots, the stability of spots, spot cooling and missing flux. The author concludes that spots should be viewed not simply as cool areas, but rather as engines which do the work of converting the energy of convective flows into flare-compatible form. (Auth.)

Respons Curvularia lunata Penyebab Penyakit Bercak Daun Kelapa Sawit terhadap Berbagai Fungisida

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Agus Susanto

2014-08-01

Full Text Available Leaf spot disease of oil palm caused by Curvularia sp. is the major disease in nursery. Implementation of best nursery practices is the key to prevent it. Generally, fungicides are used only if epidemic of leaf spot diseases occur in the field. The objectives of this research were to determine causal agent of leaf spot disease of oil palm and the potential alternative weed host around the nursery, to select suitable fungicides, and to study the effect of fungicides rotation to disease incidence. The results showed that the causal agent of leaf spot disease of oil palm was Curvularia lunata. The fungus was also found on grasses, Cyperus rotundus and Imperata cylindrica. Difeconazol, copper oxide, and propineb suppressed leaf spot disease in nursery. Application of fungicide by rotation between difeconazol and copper oxide with frequency every 10 days suppressed the development of leaf spot disease of oil palm in the nursery.

Leaf size and leaf display of thirty-eight tropical tree species

NARCIS (Netherlands)

Poorter, L.; Rozendaal, D.M.A.

2008-01-01

Trees forage for light through optimal leaf display. Effective leaf display is determined by metamer traits (i.e., the internode, petiole, and corresponding leaf), and thus these traits strongly co-determine carbon gain and as a result competitive advantage in a light-limited environment. We

Effects of spot size and spot spacing on lateral penumbra reduction when using a dynamic collimation system for spot scanning proton therapy

International Nuclear Information System (INIS)

Hyer, Daniel E; Hill, Patrick M; Wang, Dongxu; Smith, Blake R; Flynn, Ryan T

2014-01-01

The purpose of this work was to investigate the reduction in lateral dose penumbra that can be achieved when using a dynamic collimation system (DCS) for spot scanning proton therapy as a function of two beam parameters: spot size and spot spacing. This is an important investigation as both values impact the achievable dose distribution and a wide range of values currently exist depending on delivery hardware. Treatment plans were created both with and without the DCS for in-air spot sizes (σ air ) of 3, 5, 7, and 9 mm as well as spot spacing intervals of 2, 4, 6 and 8 mm. Compared to un-collimated treatment plans, the plans created with the DCS yielded a reduction in the mean dose to normal tissue surrounding the target of 26.2–40.6% for spot sizes of 3–9 mm, respectively. Increasing the spot spacing resulted in a decrease in the time penalty associated with using the DCS that was approximately proportional to the reduction in the number of rows in the raster delivery pattern. We conclude that dose distributions achievable when using the DCS are comparable to those only attainable with much smaller initial spot sizes, suggesting that the goal of improving high dose conformity may be achieved by either utilizing a DCS or by improving beam line optics. (note)

On the origin of delta spots

International Nuclear Information System (INIS)

Tang, F.

1983-01-01

Mount Wilson sunspot drawings from 1966 through 1980 were used in conjunction with Hα filtergrams from Big Bear Solar Observatory to examine the origin of delta spots, spots with bipolar umbrae within one penumbra. Of the six cases we studied, five were formed by the union of non-paired spots. They are either shoved into one another by two neighboring growing bipoles or by a new spot born piggy-back style on an existing spot of opposite polarity. Proper motions of the growing spots take on curvilinear paths around one another to avoid a collision. This is the shear motion observed in delta spots (Tanaka, 1979). In the remaining case, the delta spot was formed by spots that emerged as a pair. Our findings indicate no intrinsic differences in the formation or the behavior between delta spots of normal magnetic configuration. (orig.)

TLC profiles and antibacterial activity of Glinus oppositifolius L. Aug. DC. (Molluginaceae leaf and stem extracts against bacterial pathogens

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Juliana Janet R. Martin-Puzon

2015-07-01

Full Text Available Objective: To determine the antibacterial activities and the thin-layer chromatography (TLC fingerprint profiles of leaf and stem extracts of Glinus oppositifolius L. Aug. DC (G. oppositifolius. Methods: The leaves and stems were extracted using chloroform, ethanol and methanol as solvents. The antibacterial activity of the extracts were evaluated through disc diffusion, minimum inhibitory concentration and bactericidal concentration assays against methicillinresistant Staphylococcus aureus, vancomycin-resistant Enterococcus, extended spectrum β-lactamase-producing, carbapenem-resistant Enterobacteriaceae, and metallo-β-lactamaseproducing Pseudomonas aeruginosa (P. aeruginosa and Acinetobacter baumanii (A. baumanii. The TLC separation was carried out on leaf and stem ethanol extracts in ethyl acetate: n-hexane solvent system. Distinct spots were examined under visible light, UV 254 nm, UV 366 nm and after spraying with vanillin-sulfuric acid. Results: The leaf extracts revealed antibacterial activities, inhibiting the growth of the nonresistant and multidrug-resistant strains of the Gram-negative bacteria Escherichia coli, P. aeruginosa and A. baumanii. The TLC fingerprint profiles demonstrated the presence of various phytochemicals in leaf and stem extracts. Leaf extracts exhibited more diverse constituents compared to stem extracts, but some constituents were similar in both plant parts. Conclusions: G. oppositifolius leaf extracts can be used as new, alternative sources of antimicrobials against non-resistant and multidrug-resistant strains of the Gram-negative bacteria Escherichia coli, P. aeruginosa and A. baumanii. The TLC profiles represent the chemical integrity of G. oppositifolius leaf and stem extracts which form an important and powerful tool for standardization, authentication, quality control and determination of bioactive components of G. oppositifolius in any formulation and in powder form.

Evaluation of Methane from Sisal Leaf Residue and Palash Leaf Litter

Science.gov (United States)

Arisutha, S.; Baredar, P.; Deshpande, D. M.; Suresh, S.

2014-12-01

The aim of this study is to evaluate methane production from sisal leaf residue and palash leaf litter mixed with different bulky materials such as vegetable market waste, hostel kitchen waste and digested biogas slurry in a laboratory scale anaerobic reactor. The mixture was prepared with 1:1 proportion. Maximum methane content of 320 ml/day was observed in the case of sisal leaf residue mixed with vegetable market waste as the feed. Methane content was minimum (47 ml/day), when palash leaf litter was used as feed. This was due to the increased content of lignin and polyphenol in the feedstock which were of complex structure and did not get degraded directly by microorganisms. Sisal leaf residue mixtures also showed highest content of volatile fatty acids (VFAs) as compared to palash leaf litter mixtures. It was observed that VFA concentration in the digester first increased, reached maximum (when pH was minimum) and then decreased.

‘Breath figures’ on leaf surfaces – formation and effects of microscopic leaf wetness

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Jürgen eBurkhardt

2013-10-01

Full Text Available ‘Microscopic leaf wetness’ means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 µm, microscopic leaf wetness it is about 2 orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the amount and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g. ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

Evaluation of SPOT imagery for the estimation of grassland biomass

Science.gov (United States)

Dusseux, P.; Hubert-Moy, L.; Corpetti, T.; Vertès, F.

2015-06-01

In many regions, a decrease in grasslands and change in their management, which are associated with agricultural intensification, have been observed in the last half-century. Such changes in agricultural practices have caused negative environmental effects that include water pollution, soil degradation and biodiversity loss. Moreover, climate-driven changes in grassland productivity could have serious consequences for the profitability of agriculture. The aim of this study was to assess the ability of remotely sensed data with high spatial resolution to estimate grassland biomass in agricultural areas. A vegetation index, namely the Normalized Difference Vegetation Index (NDVI), and two biophysical variables, the Leaf Area Index (LAI) and the fraction of Vegetation Cover (fCOVER) were computed using five SPOT images acquired during the growing season. In parallel, ground-based information on grassland growth was collected to calculate biomass values. The analysis of the relationship between the variables derived from the remotely sensed data and the biomass observed in the field shows that LAI outperforms NDVI and fCOVER to estimate biomass (R2 values of 0.68 against 0.30 and 0.50, respectively). The squared Pearson correlation coefficient between observed and estimated biomass using LAI derived from SPOT images reached 0.73. Biomass maps generated from remotely sensed data were then used to estimate grass reserves at the farm scale in the perspective of operational monitoring and forecasting.

Spot market for uranium

International Nuclear Information System (INIS)

Colhoun, C.

1982-01-01

The spot market is always quoted for the price of uranium because little information is available about long-term contracts. A review of the development of spot market prices shows the same price curve swings that occur with all raw materials. Future long-term contracts will probably be lower to reflect spot market prices, which are currently in the real-value range of $30-$35. An upswing in the price of uranium could come in the next few months as utilities begin making purchases and trading from stockpiles. The US, unlike Europe and Japan, has already reached a supply and demand point where the spot market share is increasing. Forecasters cannot project the market price, they can only predict the presence of an oscillating spot or a secondary market. 5 figures

Estimating rice grain protein contents with SPOT/HRV data acquired at maturing stage

International Nuclear Information System (INIS)

Asaka, D.; Shiga, H.

2003-01-01

Rice grain protein contents that play an important role in the eating quality of rice can be estimated from leaf color in maturing stage. In order to investigate the distribution of paddy rice grain protein of a wide area, we employed SPOT/HRV data from August to September for successive 4 years, selecting the Naganuma town, Hokkaido as the study area. The relationship between each spectral bands and ground survey data were examined. The result showed that the grain protein contents could be estimated using the normalized difference vegetation index (NDVI) with the absolute root mean square error less than 0.4% under the condition that the time lag between the satellite observation date and the maturing stage was within 20 days. In this period, we would have enough chance to get clear observation data every year under the weather conditions in the study area using the SPOT/HRV sensors that has pointing ability. For major rice varieties cultivated in Hokkaido, the same relationship between NDVI and protein contents was observed. Thus, we conclude that the method proposed in this study is operational in rice production

Roth spots in pernicious anaemia.

Science.gov (United States)

Macauley, Mavin; Nag, Satyajit

2011-04-19

Roth spots are white-centred retinal haemorrhages, previously thought to be pathognomonic for subacute bacterial endocarditis. A number of other conditions can be associated with Roth spots. In this case, the authors describe the association of Roth spots and pernicious anaemia. This association has been rarely described in the medical literature. Correct diagnosis and treatment with intramuscular vitamin B(12) injections resulted in complete resolution of the anaemia and Roth spots. The authors hope to alert clinicians to think of various differentials of Roth spots, and initiate prompt investigation and management.

Comparison of outcomes between overlapping-spot and single-spot photodynamic therapy for circumscribed choroidal hemangioma

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Zhao-An Su

2014-02-01

Full Text Available AIM:To compare the efficacy and safety of photodynamic therapy (PDT with overlapping multiple spots and single spot for treating circumscribed choroidal hemangioma.METHODS:Twenty-two patients (22 eyes with symptomatic circumscribed choroidal hemangioma received PDT treatment. Fourteen patients received overlapping spots (two to three spots PDT, whereas eight patients received single-spot PDT. Laser was used at 50J/cm2 for 83s in the overlapping-spot group and 50J/cm2 for 166s in the single-spot group. Clinical examination, funduscopy, fluorescein angiography, and ultrasonography were performed at baseline and after treatment.RESULTS:The mean follow-up time was 28.5±8.0 months in the overlapping-spot group and 27.0±5.0 months in the single-spot group. Nine patients (64.2% had their vision improved over two lines on the Snellen chart, and five patients showed stable visual acuity in the overlapping-spot group. The mean thickness of tumor decreased from 2.7±0.8mm to 1.2±0.9mm, and the mean greatest tumor linear dimension decreased from 7.4±1.5mm to 4.5±3.5mm after treatment. In the single-spot group, two patients (25% had their vision improved over two lines on the Snellen chart, and six patients had unchanged stable vision. The mean tumor thickness in this group decreased from 2.5±0.7mm to 1.4±1.0mm, and the mean greatest tumor linear dimension decreased from 7.2±1.3mm to 4.7±3.6mm. No significant differences in visual improvement and tumor regression were found between the two groups.CONCLUSION: Overlapping-spot PDT under appropriate treatment parameters and strategies is as effective and safe as single-spot PDT for treating symptomatic circumscribed choroidal hemangioma. Improved or stabilized visual acuity was achieved as a result of tumor regression.

Differential gene expression in soybean leaf tissues at late developmental stages under drought stress revealed by genome-wide transcriptome analysis.

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Dung Tien Le

Full Text Available The availability of complete genome sequence of soybean has allowed research community to design the 66 K Affymetrix Soybean Array GeneChip for genome-wide expression profiling of soybean. In this study, we carried out microarray analysis of leaf tissues of soybean plants, which were subjected to drought stress from late vegetative V6 and from full bloom reproductive R2 stages. Our data analyses showed that out of 46,093 soybean genes, which were predicted with high confidence among approximately 66,000 putative genes, 41,059 genes could be assigned with a known function. Using the criteria of a ratio change > = 2 and a q-value<0.05, we identified 1458 and 1818 upregulated and 1582 and 1688 downregulated genes in drought-stressed V6 and R2 leaves, respectively. These datasets were classified into 19 most abundant biological categories with similar proportions. There were only 612 and 463 genes that were overlapped among the upregulated and downregulated genes, respectively, in both stages, suggesting that both conserved and unconserved pathways might be involved in regulation of drought response in different stages of plant development. A comparative expression analysis using our datasets and that of drought stressed Arabidopsis leaves revealed the existence of both conserved and species-specific mechanisms that regulate drought responses. Many upregulated genes encode either regulatory proteins, such as transcription factors, including those with high homology to Arabidopsis DREB, NAC, AREB and ZAT/STZ transcription factors, kinases and two-component system members, or functional proteins, e.g. late embryogenesis-abundant proteins, glycosyltransferases, glycoside hydrolases, defensins and glyoxalase I family proteins. A detailed analysis of the GmNAC family and the hormone-related gene category showed that expression of many GmNAC and hormone-related genes was altered by drought in V6 and/or R2 leaves. Additionally, the downregulation of

A method to investigate drivers' acceptance of Blind Spot Detection System®.

Science.gov (United States)

Piccinini, Giuliofrancesco; Simões, Anabela; Rodrigues, Carlos Manuel; Leitão, Miguel

2012-01-01

Lately, with the goal of improving road safety, car makers developed and commercialised some Advanced Driver Assistance Systems (ADAS) which, through the detection of blind spot areas on the vehicle's sides, could help the drivers during the overtaking and the change lane task. Despite the possible benefits to reduce lateral crashes, the overall impact on road safety of such systems have not been deeply studied yet; notably, despite some researches have been carried out, there is a lack of studies regarding the long-term usage and drivers' acceptance of those systems. In order to fill the research gap, a methodology, based on the combination of focus groups interviews, questionnaires and a small-scale field operational test (FOT), has been designed in this study; such a methodology aims at evaluating drivers' acceptance of Blind Spot Information System® and at proposing some ideas to improve the usability and user-friendliness of this (or similar) device in their future development.

Effect of greenhouse conditions on the leaf apoplastic proteome of Coffea arabica plants.

Science.gov (United States)

Guerra-Guimarães, Leonor; Vieira, Ana; Chaves, Inês; Pinheiro, Carla; Queiroz, Vagner; Renaut, Jenny; Ricardo, Cândido P

2014-06-02

This work describes the coffee leaf apoplastic proteome and its modulation by the greenhouse conditions. The apoplastic fluid (APF) was obtained by leaf vacuum infiltration, and the recovered proteins were separated by 2-DE and subsequently identified by matrix assisted laser desorption/ionization time of flight-mass spectrometry, followed by homology search in EST coffee databases. Prediction tools revealed that the majority of the 195 identified proteins are involved in cell wall metabolism and in stress/defense responses. Although most of the proteins follow the classical secretory mechanism, a low percentage of them seem to result from unconventional secretion (leaderless secreted proteins). Principal components analysis revealed that the APF samples formed two distinct groups, with the temperature amplitude mostly contributing for this separation (higher or lower than 10°C, respectively). Sixty one polypeptide spots allowed defining these two groups and 28 proteins were identified, belonging to carbohydrate metabolism, cell wall modification and proteolysis. Interestingly stress/defense proteins appeared as more abundant in Group I which is associated with a higher temperature amplitude. It seems that the proteins in the coffee leaf APF might be implicated in structural modifications in the extracellular space that are crucial for plant development/adaptation to the conditions of the prevailing environment. This is the first detailed proteomic study of the coffee leaf apoplastic fluid (APF) and of its modulation by the greenhouse conditions. The comprehensive overview of the most abundant proteins present in the extra-cellular compartment is particularly important for the understanding of coffee responses to abiotic/biotic stress. This article is part of a Special Issue entitled: Environmental and structural proteomics. Copyright © 2014 Elsevier B.V. All rights reserved.

Seasonal profiles of leaf ascorbic acid content and redox state in ozone-sensitive wildflowers

International Nuclear Information System (INIS)

Burkey, Kent O.; Neufeld, Howard S.; Souza, Lara; Chappelka, Arthur H.; Davison, Alan W.

2006-01-01

Cutleaf coneflower (Rudbeckia laciniata L.), crown-beard (Verbesina occidentalis Walt.), and tall milkweed (Asclepias exaltata L.) are wildflower species native to Great Smoky Mountains National Park (U.S.A.). Natural populations of each species were analyzed for leaf ascorbic acid (AA) and dehydroascorbic acid (DHA) to assess the role of ascorbate in protecting the plants from ozone stress. Tall milkweed contained greater quantities of AA (7-10 μmol g -1 fresh weight) than crown-beard (2-4 μmol g -1 fresh weight) or cutleaf coneflower (0.5-2 μmol g -1 fresh weight). DHA was elevated in crown-beard and cutleaf coneflower relative to tall milkweed suggesting a diminished capacity for converting DHA into AA. Tall milkweed accumulated AA in the leaf apoplast (30-100 nmol g -1 fresh weight) with individuals expressing ozone foliar injury symptoms late in the season having less apoplast AA. In contrast, AA was not present in the leaf apoplast of either crown-beard or cutleaf coneflower. Unidentified antioxidant compounds were present in the leaf apoplast of all three species. Overall, distinct differences in antioxidant metabolism were found in the wildflower species that corresponded with differences in ozone sensitivity. - Wildflower species exhibit differences in ascorbic acid content and redox status that affect ozone sensitivity

Leaf habit and woodiness regulate different leaf economy traits at a given nutrient supply.

Science.gov (United States)

Ordoñez, Jenny C; van Bodegom, Peter M; Witte, Jan-Philip M; Bartholomeus, Ruud P; van Dobben, Han F; Aerts, Rien

2010-11-01

The large variation in the relationships between environmental factors and plant traits observed in natural communities exemplifies the alternative solutions that plants have developed in response to the same environmental limitations. Qualitative attributes, such as growth form, woodiness, and leaf habit can be used to approximate these alternative solutions. Here, we quantified the extent to which these attributes affect leaf trait values at a given resource supply level, using measured plant traits from 105 different species (254 observations) distributed across 50 sites in mesic to wet plant communities in The Netherlands. For each site, soil total N, soil total P, and water supply estimates were obtained by field measurements and modeling. Effects of growth forms, woodiness, and leaf habit on relations between leaf traits (SLA, specific leaf area; LNC, leaf nitrogen concentration; and LPC, leaf phosphorus concentration) vs. nutrient and water supply were quantified using maximum-likelihood methods and Bonferroni post hoc tests. The qualitative attributes explained 8-23% of the variance within sites in leaf traits vs. soil fertility relationships, and therefore they can potentially be used to make better predictions of global patterns of leaf traits in relation to nutrient supply. However, at a given soil fertility, the strength of the effect of each qualitative attribute was not the same for all leaf traits. These differences may imply a differential regulation of the leaf economy traits at a given nutrient supply, in which SLA and LPC seem to be regulated in accordance to changes in plant size and architecture while LNC seems to be primarily regulated at the leaf level by factors related to leaf longevity.

Effect of Addition of Moringa Leaf By-Product (Leaf-Waste) on ...

African Journals Online (AJOL)

The effects of incorporation of Moringa leaf fibre (a by-product of leaf processing which contains 24% Crude Fibre by dry weight at 0, 5 and 10 % substitution of wheat flour in cookies was investigated. Three products containing wheat flour: Moringa leaf fibre ratios of 100:0, 95:5, and 90:10 respectively were prepared, and a ...

Evaluation of Off-season Potential Breeding Sources for Spotted Wing Drosophila (Drosophila suzukii Matsumura) in Michigan.

Science.gov (United States)

Bal, Harit K; Adams, Christopher; Grieshop, Matthew

2017-12-05

It has been suggested that fruit wastes including dropped and unharvested fruits, and fruit byproducts (i.e., pomace) found in fruit plantings and cideries or wine-making facilities could serve as potential off-season breeding sites for spotted wing Drosophila (Drosophila suzukii Matsumura (Diptera: Drosophilidae)). This idea, however, has yet to be widely tested. The goal of our study was to determine the potential of dropped fruit and fruit wastes as Fall spotted wing Drosophila breeding resources in Michigan, USA. Fruit waste samples were collected from 15 farms across the lower peninsula of Michigan and were evaluated for spotted wing Drosophila and other drosophilid emergence and used in host suitability bioassays. All of the dropped apples, pears, grapes, and raspberries and 40% of apple and 100% of grape fruit pomace evaluated were found to contain spotted wing Drosophila with the highest numbers collected from dropped grapes and pears. Greater spotted wing Drosophila recovery was found in fruit wastes at sites attached with cideries and wine-making facilities and with multiple cultivated fruit crops than sites with no cideries and only one crop. Females oviposited in raspberry, pear, apple, grape, apple pomace and grape pomace samples with the highest rates of reproduction in raspberries. Our results demonstrate that fruit wastes including dropped berry, pomme and stone fruits, as well as fruit compost may be important late season reproductive resources for spotted wing Drosophila. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Distribution, survivorship and mortality sources in immature stages of the neotropical leaf miner Pachyschelus coeruleipennis Kerremans (Coleoptera: Buprestidae

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QUEIROZ J. M.

2002-01-01

Full Text Available Distribution, sources of mortality, and survivorship of immatures was investigated during the reproductive season of the neotropical buprestid leaf miner, Pachyschelus coeruleipennis, that burrows in leaves of Croton floribundus (Euphorbiaceae in SE, Brazil. Immature distribution was investigated by a random sample of 120 shrubs of C. floribundus growing along forest edges. Marked leaves were followed to recorded sources of mortality and survivorship of immature stages. Females lay their eggs preferentially in the young leaves of the host plant, with mines and pupal cells having been found on the middle part of plants. Densities of eggs, active mines, and pupal cells were, respectively, 25 ± 2, 6 ± 1, and 1 ± 0.3 per 100 leaves. Predators and parasitoids accounted for the majority of losses in the immature P. coeruleipennis population. Mortality was 3 times lower in the egg stage than in the last larval instar. Predation rate was greater than parasitism but the latter increased much more during the development of immatures. Survivorship and sources of mortality were different between early and late season sample of leaf-miner immatures. Parasitism rate was greater in the late-season whereas predation was greater in early-season samples. These results are compared with mortality patterns described for other buprestid leaf miners in temperate and tropical regions.

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

Science.gov (United States)

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.

SpotCaliper: fast wavelet-based spot detection with accurate size estimation.

Science.gov (United States)

Püspöki, Zsuzsanna; Sage, Daniel; Ward, John Paul; Unser, Michael

2016-04-15

SpotCaliper is a novel wavelet-based image-analysis software providing a fast automatic detection scheme for circular patterns (spots), combined with the precise estimation of their size. It is implemented as an ImageJ plugin with a friendly user interface. The user is allowed to edit the results by modifying the measurements (in a semi-automated way), extract data for further analysis. The fine tuning of the detections includes the possibility of adjusting or removing the original detections, as well as adding further spots. The main advantage of the software is its ability to capture the size of spots in a fast and accurate way. http://bigwww.epfl.ch/algorithms/spotcaliper/ zsuzsanna.puspoki@epfl.ch Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Effect of nitrogen supply on leaf appearance, leaf growth, leaf nitrogen economy and photosynthetic capacity in maize (Zea mays L.)

NARCIS (Netherlands)

Vos, J.; Putten, van der P.E.L.; Birch, C.J.

2005-01-01

Leaf area growth and nitrogen concentration per unit leaf area, Na (g m-2 N) are two options plants can use to adapt to nitrogen limitation. Previous work indicated that potato (Solanum tuberosum L.) adapts the size of leaves to maintain Na and photosynthetic capacity per unit leaf area. This paper

Roth spots in pernicious anaemia

OpenAIRE

Macauley, Mavin; Nag, Satyajit

2011-01-01

Roth spots are white-centred retinal haemorrhages, previously thought to be pathognomonic for subacute bacterial endocarditis. A number of other conditions can be associated with Roth spots. In this case, the authors describe the association of Roth spots and pernicious anaemia. This association has been rarely described in the medical literature. Correct diagnosis and treatment with intramuscular vitamin B12 injections resulted in complete resolution of the anaemia and Roth spots. The author...

SU-F-T-350: Continuous Leaf Optimization (CLO) for IMRT Leaf Sequencing

Energy Technology Data Exchange (ETDEWEB)

Long, T; Chen, M; Jiang, S; Lu, W [UT Southwestern Medical Center, Dallas, TX (United States)

2016-06-15

Purpose: To study a new step-and-shoot IMRT leaf sequencing model that avoids the two main pitfalls of conventional leaf sequencing: (1) target fluence being stratified into a fixed number of discrete levels and/or (2) aperture leaf positions being restricted to a discrete set of locations. These assumptions induce error into the sequence or reduce the feasible region of potential plans, respectively. Methods: We develop a one-dimensional (single leaf pair) methodology that does not make assumptions (1) or (2) that can be easily extended to a multi-row model. The proposed continuous leaf optimization (CLO) methodology takes in an existing set of apertures and associated intensities, or solution “seed,” and improves the plan without the restrictiveness of 1or (2). It then uses a first-order descent algorithm to converge onto a locally optimal solution. A seed solution can come from models that assume (1) and (2), thus allowing the CLO model to improve upon existing leaf sequencing methodologies. Results: The CLO model was applied to 208 generated target fluence maps in one dimension. In all cases for all tested sequencing strategies, the CLO model made improvements on the starting seed objective function. The CLO model also was able to keep MUs low. Conclusion: The CLO model can improve upon existing leaf sequencing methods by avoiding the restrictions of (1) and (2). By allowing for more flexible leaf positioning, error can be reduced when matching some target fluence. This study lays the foundation for future models and solution methodologies that can incorporate continuous leaf positions explicitly into the IMRT treatment planning model. Supported by Cancer Prevention & Research Institute of Texas (CPRIT) - ID RP150485.

Ionospheric hot spot at high latitudes

International Nuclear Information System (INIS)

Schunk, R.W.; Sojka, J.J.

1982-01-01

A hot spot (or spots) can occur in the high-latitude ionosphere depending on the plasma convection pattern. The hot spot corresponds to a small magnetic local time-magnetic latitude region of elevated ion temperatures located near the dusk and/or dawn meridians. For asymmetric convection electric field patterns, with enhanced flow in either the dusk or dawn sector of the polar cap, a single hot spot should occur in association with the strong convection cell. However, on geomagnetically disturbed days, two strong convection cells can occur, and hence, two hot spots should exist. The hot spot should be detectable when the electric field in the strong convection cell exceeds about 40 mV m -1 . For electric fields of the order of 100 mV m -1 in the convection cell, the ion temperature in the hot spot is greatest at low altitudes, reaching 4000 0 K at 160 km, and decreases with altitude in the F-region. An ionospheric hot spot (or spots) can be expected at all seasons and for a wide range of solar cycle conditions

A new Late Devonian genus with seed plant affinities.

Science.gov (United States)

Wang, Deming; Liu, Le

2015-02-26

Many ovules of Late Devonian (Famennian) seed plants have been well studied. However, because few taxa occur with anatomically preserved stems and/or petioles, the vascular system of these earliest spermatophytes is little understood and available data come mostly from Euramerica. There remains great controversy over the anatomical differentiation of Late Devonian and Carboniferous seed plant groups of Buteoxylonales, Calamopityales and Lyginopteridales. Protostele evolution of these early spermatophytes needs more research. A new taxon Yiduxylon trilobum gen. et sp. nov. with seed plant affinities has been discovered in the Upper Devonian (Famennian) Tizikou Formation of Hubei Province, China. It is represented by stems, helically arranged and bifurcate fronds with two orders of pinnae and planate pinnules. Both secondary pinnae and pinnules are borne alternately. Stems contain a small protostele with three primary xylem ribs possessing a single peripheral protoxylem strand. Thick secondary xylem displays multiseriate bordered pitting on the tangential and radial walls of the tracheids, and has biseriate to multiseriate and high rays. A narrow cortex consists of inner cortex without sclerotic nests and sparganum-type outer cortex with peripheral bands of vertically aligned sclerenchyma cells. Two leaf traces successively arise tangentially from each primary xylem rib and they divide once to produce four circular-oval traces in the stem cortex. Four vascular bundles occur in two C-shaped groups at each petiole base with ground tissue and peripheral bands of sclerenchyma cells. Yiduxylon justifies the assignment to a new genus mainly because of the protostele with protoxylem strands only near the periphery of primary xylem ribs, leaf trace origination and petiolar vascular supply structure. It shares many definitive characters with Calamopityales and Lyginopteridales, further underscoring the anatomical similarities among early seed plants. The primary vascular

Variable-spot ion beam figuring

International Nuclear Information System (INIS)

Wu, Lixiang; Qiu, Keqiang; Fu, Shaojun

2016-01-01

This paper introduces a new scheme of ion beam figuring (IBF), or rather variable-spot IBF, which is conducted at a constant scanning velocity with variable-spot ion beam collimated by a variable diaphragm. It aims at improving the reachability and adaptation of the figuring process within the limits of machine dynamics by varying the ion beam spot size instead of the scanning velocity. In contrast to the dwell time algorithm in the conventional IBF, the variable-spot IBF adopts a new algorithm, which consists of the scan path programming and the trajectory optimization using pattern search. In this algorithm, instead of the dwell time, a new concept, integral etching time, is proposed to interpret the process of variable-spot IBF. We conducted simulations to verify its feasibility and practicality. The simulation results indicate the variable-spot IBF is a promising alternative to the conventional approach.

On the temporal variation of leaf magnetic parameters: seasonal accumulation of leaf-deposited and leaf-encapsulated particles of a roadside tree crown.

Science.gov (United States)

Hofman, Jelle; Wuyts, Karen; Van Wittenberghe, Shari; Samson, Roeland

2014-09-15

Understanding the accumulation behaviour of atmospheric particles inside tree leaves is of great importance for the interpretation of biomagnetic monitoring results. In this study, we evaluated the temporal variation of the saturation isothermal remanent magnetisation (SIRM) of leaves of a roadside urban Platanus × acerifolia Willd. tree in Antwerp, Belgium. We hereby examined the seasonal development of the total leaf SIRM signal as well as the leaf-encapsulated fraction of the deposited dust, by washing the leaves before biomagnetic analysis. On average 38% of the leaf SIRM signal was exhibited by the leaf-encapsulated particles. Significant correlations were found between the SIRM and the cumulative daily average atmospheric PM10 and PM2.5 measurements. Moreover, a steady increase of the SIRM throughout the in-leaf season was observed endorsing the applicability of biomagnetic monitoring as a proxy for the time-integrated PM exposure of urban tree leaves. Strongest correlations were obtained for the SIRM of the leaf-encapsulated particles which confirms the dynamic nature of the leaf surface-accumulated particles. Copyright © 2014 Elsevier B.V. All rights reserved.

Rapid green synthesis of spherical gold nanoparticles using Mangifera indica leaf

Science.gov (United States)

Philip, Daizy

2010-11-01

This paper reports the rapid biological synthesis of spherical gold nanoparticles at room temperature using fresh/dry leaf extract of Mangifera indica. This is a simple, cost-effective, stable for long time and reproducible aqueous synthesis method to obtain a self-assembly of nearly monodispersed Au nanoparticles of size ˜20 nm and 17 nm. The nanoparticles were obtained within 2 min of addition of the extract to the solution of HAuCl 4·3H 2O and the colloid is found to be stable for more than 5 months. Smaller and more uniformly distributed particles could be obtained with dried leaf extract. The nanoparticles obtained are characterized by UV-vis, transmission electron microscopy (TEM) and X-ray diffraction (XRD). Crystalline nature of the nanoparticles in the fcc structure is confirmed by the peaks in the XRD pattern corresponding to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes, bright circular spots in the selected area electron diffraction (SAED) and clear lattice fringes in the high-resolution TEM image. The possible biomolecules responsible for efficient stabilization are suggested by studying the FTIR spectrum of the sample. This environmentally benign method provides much faster synthesis and colloidal stability comparable to those of chemical reduction.

[Study on Hexagonal Super-Lattice Pattern with Light Spot and Dim Spot in Dielectric Barrier Discharge by Optical Emission Spectra].

Science.gov (United States)

Liu, Ying; Dong, Li-fang; Niu, Xue-jiao; Zhang, Chao

2016-02-01

The hexagonal super-lattice pattern composed of the light spot and the dim spot is firstly observed and investigated in the discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It is found that the dim spot is located at the center of its surrounding three light spots by observing the discharge image. Obviously, the brightness of the light spot and the dim spot are different, which indicates that the plasma states of the light spot and the dim spot may be different. The optical emission spectrum method is used to further study the several plasma parameters of the light spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³IIg) are measured, from which the molecule vibration temperatures of the light spot and the dim spot are calculated. Based on the relative intensity ratio of the line at 391.4 nm and the N₂ line at 394.1 nm, the average electron energies of the light spot and the dim spot are investigated. The broadening of spectral line 696.57 nm (2P₂-1S₅) is used to study the electron densities of the light spot and the dim spot. The experiment shows that the molecule vibration temperature, average electron energy and the electron density of the dim spot are higher than those of the light spot in the same argon content. The molecule vibration temperature and electron density of the light spot and dim spot increase with the argon content increasing from 70% to 95%, while average electron energies of the light spot and dim spot decrease gradually. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The surface discharge induced by the volume discharge (VD) has the decisive effect on the formation of the dim spot. The experiment above plays an important role in studying the formation mechanism of the hexagonal super-lattice pattern with light spot and

Effect of Wind on the Relation of Leaf N, P Stoichiometry with Leaf Morphology in Quercus Species

Directory of Open Access Journals (Sweden)

Peng Zhang

2018-02-01

Full Text Available Leaf nitrogen (N and phosphorus (P stoichiometry correlates closely to leaf morphology, which is strongly impacted by wind at multiple scales. However, it is not clear how leaf N, P stoichiometry and its relationship to leaf morphology changes with wind load. We determined the leaf N and P concentrations and leaf morphology—including specific leaf area (SLA and leaf dissection index (LDI—for eight Quercus species under a simulated wind load for seven months. Leaf N and P concentrations increased significantly under these conditions for Quercus acutissima, Quercus rubra, Quercus texana, and Quercus palustris—which have elliptic leaves—due to their higher N, P requirements and a resultant leaf biomass decrease, which is a tolerance strategy for Quercus species under a wind load. Leaf N:P was relatively stable under wind for all species, which supports stoichiometric homeostasis. Leaf N concentrations showed a positive correlation to SLA, leaf N and P concentrations showed positive correlations to LDI under each wind treatment, and the slope of correlations was not affected by wind, which indicates synchronous variations between leaf stoichiometry and leaf morphology under wind. However, the intercept of correlations was affected by wind, and leaf N and P use efficiency decreased under the wind load, which suggests that the Quercus species changes from “fast investment-return” in the control to “slow investment-return” under windy conditions. These results will be valuable to understanding functional strategies for plants under varying wind loads, especially synchronous variations in leaf traits along a wind gradient.

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

Directory of Open Access Journals (Sweden)

BRUNO H.P. ROSADO

2013-09-01

Full Text Available 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.

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

Science.gov (United States)

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.

Numerical optimisation in spot detector design

NARCIS (Netherlands)

van der Heijden, Ferdinand; Apperloo, W.; Spreeuwers, Lieuwe Jan

1997-01-01

Spots are image details resulting from objects, the projections of which are so small that the inner structure of these objects cannot be resolved from their image. Spot detectors are image operators aiming at the detection and localisation of spots in the image. Most spot detectors can be tuned

9 CFR 149.4 - Spot audit.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Spot audit. 149.4 Section 149.4... LIVESTOCK IMPROVEMENT VOLUNTARY TRICHINAE CERTIFICATION PROGRAM § 149.4 Spot audit. (a) In addition to regularly scheduled site audits, certified production sites will be subject to spot audits. (1) Random spot...

How do leaf veins influence the worldwide leaf economic spectrum? Review and synthesis.

Science.gov (United States)

Sack, Lawren; Scoffoni, Christine; John, Grace P; Poorter, Hendrik; Mason, Chase M; Mendez-Alonzo, Rodrigo; Donovan, Lisa A

2013-10-01

Leaf vein traits are implicated in the determination of gas exchange rates and plant performance. These traits are increasingly considered as causal factors affecting the 'leaf economic spectrum' (LES), which includes the light-saturated rate of photosynthesis, dark respiration, foliar nitrogen concentration, leaf dry mass per area (LMA) and leaf longevity. This article reviews the support for two contrasting hypotheses regarding a key vein trait, vein length per unit leaf area (VLA). Recently, Blonder et al. (2011, 2013) proposed that vein traits, including VLA, can be described as the 'origin' of the LES by structurally determining LMA and leaf thickness, and thereby vein traits would predict LES traits according to specific equations. Careful re-examination of leaf anatomy, published datasets, and a newly compiled global database for diverse species did not support the 'vein origin' hypothesis, and moreover showed that the apparent power of those equations to predict LES traits arose from circularity. This review provides a 'flux trait network' hypothesis for the effects of vein traits on the LES and on plant performance, based on a synthesis of the previous literature. According to this hypothesis, VLA, while virtually independent of LMA, strongly influences hydraulic conductance, and thus stomatal conductance and photosynthetic rate. We also review (i) the specific physiological roles of VLA; (ii) the role of leaf major veins in influencing LES traits; and (iii) the role of VLA in determining photosynthetic rate per leaf dry mass and plant relative growth rate. A clear understanding of leaf vein traits provides a new perspective on plant function independently of the LES and can enhance the ability to explain and predict whole plant performance under dynamic conditions, with applications towards breeding improved crop varieties.

Seasonal profiles of leaf ascorbic acid content and redox state in ozone-sensitive wildflowers

Energy Technology Data Exchange (ETDEWEB)

Burkey, Kent O. [Plant Science Research Unit, USDA-ARS and North Carolina State University, 3127 Ligon Street, Raleigh, NC 27607 (United States)]. E-mail: koburkey@unity.ncsu.edu; Neufeld, Howard S. [Appalachian State University, Boone, NC (United States); Souza, Lara [Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN (United States); Chappelka, Arthur H. [Auburn University, Auburn, AL (United States); Davison, Alan W. [University of Newcastle, Newcastle, England (United Kingdom)

2006-10-15

Cutleaf coneflower (Rudbeckia laciniata L.), crown-beard (Verbesina occidentalis Walt.), and tall milkweed (Asclepias exaltata L.) are wildflower species native to Great Smoky Mountains National Park (U.S.A.). Natural populations of each species were analyzed for leaf ascorbic acid (AA) and dehydroascorbic acid (DHA) to assess the role of ascorbate in protecting the plants from ozone stress. Tall milkweed contained greater quantities of AA (7-10 {mu}mol g{sup -1} fresh weight) than crown-beard (2-4 {mu}mol g{sup -1} fresh weight) or cutleaf coneflower (0.5-2 {mu}mol g{sup -1} fresh weight). DHA was elevated in crown-beard and cutleaf coneflower relative to tall milkweed suggesting a diminished capacity for converting DHA into AA. Tall milkweed accumulated AA in the leaf apoplast (30-100 nmol g{sup -1} fresh weight) with individuals expressing ozone foliar injury symptoms late in the season having less apoplast AA. In contrast, AA was not present in the leaf apoplast of either crown-beard or cutleaf coneflower. Unidentified antioxidant compounds were present in the leaf apoplast of all three species. Overall, distinct differences in antioxidant metabolism were found in the wildflower species that corresponded with differences in ozone sensitivity. - Wildflower species exhibit differences in ascorbic acid content and redox status that affect ozone sensitivity.

Spot formation of radiation particles by electrochemical etching

International Nuclear Information System (INIS)

Nozaki, Tetsuya

1999-01-01

An electrochemical etching (ECE) spot formation from the top of chemical etching (CE) spot was confirmed by a series of experiments. One of polycarbonate (Iupilon) could not make the spot, because ECE spot had grown up before the microscope confirming the CE spot. Clear CEC spots by α-ray and neutron were found on Harzlas and Baryotrak, both improvements of CR-39. Under the same etching conditions, the growth of ECE spot on Harzlas was more rapid than Baryotrak, but both spots were almost the same. All CE spot by α-ray produced the CEC spots, but a part of CE circle spot by neutron formed them. (S.Y.)

An evolutionary perspective on leaf economics : Phylogenetics of leaf mass per area in vascular plants

NARCIS (Netherlands)

Flores, Olivier; Garnier, Eric; Wright, Ian J.; Reich, Peter B.; Pierce, Simon; Diaz, Sandra; Pakeman, Robin J.; Rusch, Graciela M.; Bernard-Verdier, Maud; Testi, Baptiste; Bakker, Jan P.; Bekker, Renee 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.; Perez-Harguindeguy, Natalia; Vendramini, Fernanda; Weiher, Evan

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

Managing emerging threats to spotted owls

Science.gov (United States)

Ho Yi Wan; Joseph L. Ganey; Christina D. Vojta; Samuel A. Cushman

2018-01-01

The 3 spotted owl (Strix occidentalis) subspecies in North America (i.e., northern spotted owl [S. o. caurina], California spotted owl [S. o. occidentalis], Mexican spotted owl [S. o. lucida]) have all experienced population declines over the past century due to habitat loss and fragmentation from logging. Now, the emerging influences of climate change, high-severity...

Spot-Scanning Proton Radiation Therapy for Pediatric Chordoma and Chondrosarcoma: Clinical Outcome of 26 Patients Treated at Paul Scherrer Institute

Energy Technology Data Exchange (ETDEWEB)

Rombi, Barbara [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland); ATreP (Provincial Agency for Proton Therapy), Trento (Italy); Ares, Carmen, E-mail: carmen.ares@psi.ch [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland); Hug, Eugen B. [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland); ProCure Proton Therapy Center, Somerset, New Jersey (United States); Schneider, Ralf; Goitein, Gudrun; Staab, Adrian; Albertini, Francesca; Bolsi, Alessandra; Lomax, Antony J. [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland); Timmermann, Beate [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland); WestGerman Proton Therapy Center Essen (Germany)

2013-07-01

Purpose: To evaluate the clinical results of fractionated spot-scanning proton radiation therapy (PT) in 26 pediatric patients treated at Paul Scherrer Institute for chordoma (CH) or chondrosarcoma (CS) of the skull base or axial skeleton. Methods and Materials: Between June 2000 and June 2010, 19 CH and 7 CS patients with tumors originating from the skull base (17) and the axial skeleton (9) were treated with PT. Mean age at the time of PT was 13.2 years. The mean prescribed dose was 74 Gy (relative biological effectiveness [RBE]) for CH and 66 Gy (RBE) for CS, at a dose of 1.8-2.0 Gy (RBE) per fraction. Results: Mean follow-up was 46 months. Actuarial 5-year local control (LC) rates were 81% for CH and 80% for CS. Actuarial 5-year overall survival (OS) was 89% for CH and 75% for CS. Two CH patients had local failures: one is alive with evidence of disease, while the other patient succumbed to local recurrence in the surgical pathway. One CS patient died of local progression of the disease. No high-grade late toxicities were observed. Conclusions: Spot-scanning PT for pediatric CH and CS patients resulted in excellent clinical outcomes with acceptable rates of late toxicity. Longer follow-up time and larger cohort are needed to fully assess tumor control and late effects of treatment.

Computational Prediction of Hot Spot Residues

Science.gov (United States)

Morrow, John Kenneth; Zhang, Shuxing

2013-01-01

Most biological processes involve multiple proteins interacting with each other. It has been recently discovered that certain residues in these protein-protein interactions, which are called hot spots, contribute more significantly to binding affinity than others. Hot spot residues have unique and diverse energetic properties that make them challenging yet important targets in the modulation of protein-protein complexes. Design of therapeutic agents that interact with hot spot residues has proven to be a valid methodology in disrupting unwanted protein-protein interactions. Using biological methods to determine which residues are hot spots can be costly and time consuming. Recent advances in computational approaches to predict hot spots have incorporated a myriad of features, and have shown increasing predictive successes. Here we review the state of knowledge around protein-protein interactions, hot spots, and give an overview of multiple in silico prediction techniques of hot spot residues. PMID:22316154

Poisson Spot with Magnetic Levitation

Science.gov (United States)

Hoover, Matthew; Everhart, Michael; D'Arruda, Jose

2010-01-01

In this paper we describe a unique method for obtaining the famous Poisson spot without adding obstacles to the light path, which could interfere with the effect. A Poisson spot is the interference effect from parallel rays of light diffracting around a solid spherical object, creating a bright spot in the center of the shadow.

Time Resolved X-Ray Spot Size Diagnostic

CERN Document Server

Richardson, Roger; Falabella, Steven; Guethlein, Gary; Raymond, Brett; Weir, John

2005-01-01

A diagnostic was developed for the determination of temporal history of an X-ray spot. A pair of thin (0.5 mm) slits image the x-ray spot to a fast scintillator which is coupled to a fast detector, thus sampling a slice of the X-Ray spot. Two other scintillator/detectors are used to determine the position of the spot and total forward dose. The slit signal is normalized to the dose and the resulting signal is analyzed to get the spot size. The position information is used to compensate for small changes due to spot motion and misalignment. The time resolution of the diagnostic is about 1 ns and measures spots from 0.5 mm to over 3 mm. The theory and equations used to calculate spot size and position are presented, as well as data. The calculations assume a symmetric, Gaussian spot. The spot data is generated by the ETA II accelerator, a 2kA, 5.5 MeV, 60ns electron beam focused on a Tantalum target. The spot generated is typically about 1 mm FWHM. Comparisons are made to an X-ray pinhole camera which images th...

Easy Leaf Area: Automated digital image analysis for rapid and accurate measurement of leaf area.

Science.gov (United States)

Easlon, Hsien Ming; Bloom, Arnold J

2014-07-01

Measurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. • Easy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. • Easy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images.

Temporal Gene Expression Profiling of the Wheat Leaf Rust Pathosystem Using cDNA Microarray Reveals Differences in Compatible and Incompatible Defence Pathways

OpenAIRE

Fofana, Bourlaye; Banks, Travis W.; McCallum, Brent; Strelkov, Stephen E.; Cloutier, Sylvie

2007-01-01

In this study, we detail the construction of a custom cDNA spotted microarray containing 7728 wheat ESTs and the use of the array to identify host genes that are differentially expressed upon challenges with leaf rust fungal pathogens. Wheat cultivar RL6003 (Thatcher Lr1) was inoculated with Puccinia triticina virulence phenotypes BBB (incompatible) or TJB (7-2) (compatible) and sampled at four different time points (3, 6, 12, and 24 hours) after inoculation. Transcript expression levels rela...

Statistical hot spot analysis of reactor cores

International Nuclear Information System (INIS)

Schaefer, H.

1974-05-01

This report is an introduction into statistical hot spot analysis. After the definition of the term 'hot spot' a statistical analysis is outlined. The mathematical method is presented, especially the formula concerning the probability of no hot spots in a reactor core is evaluated. A discussion with the boundary conditions of a statistical hot spot analysis is given (technological limits, nominal situation, uncertainties). The application of the hot spot analysis to the linear power of pellets and the temperature rise in cooling channels is demonstrated with respect to the test zone of KNK II. Basic values, such as probability of no hot spots, hot spot potential, expected hot spot diagram and cumulative distribution function of hot spots, are discussed. It is shown, that the risk of hot channels can be dispersed equally over all subassemblies by an adequate choice of the nominal temperature distribution in the core

Leaf anatomical traits determine the 18O enrichment of leaf water in coastal halophytes

Science.gov (United States)

Liang, J.; Lin, G., Sr.; Sternberg, L. O.

2017-12-01

Foliar anatomical adaptations to high-salinity environment in mangroves may be recorded by leaf water isotopes. Recent studies observed that a few mangrove species have lower 18O enrichment of leaf water (ΔL) relative to source water than the adjacent terrestrial trees, but what factors actually control this phenomenon is still disputable at present. To resolve this issue, we collected 15 species of true mangrove plants, 14 species of adjacent freshwater trees and 4 species of semi-mangrove plants at five study sites on the southeastern coast of China. Leaf stomatal density and pore size, water content, ΔL and other related leaf physiological traits were determined for the selected leaves of these plants. Our results confirmed that ΔL values of mangroves were generally 3 4 ‰ lower than those of the adjacent freshwater or semi-mangrove species. Higher leaf water per area (LWC) and lower leaf stomatal density (LS) of mangroves played co-dominant roles in lowering ΔL through elongating effective leaf mixing length by about 20%. The Péclet model incorporated by LWC and LS performed well in predicting ΔL. The demonstrated general law between leaf anatomy and ΔL in this paper based on a large pool of species bridges the gap between leaf functional traits and metabolic proxies derived ΔL, which will have considerable potential applications in vegetation succession and reconstruction of paleoclimate research.

Late-onset persistent retinal microvascular changes after bone marrow transplantation: 3-year follow-up

Directory of Open Access Journals (Sweden)

Muccioli Cristina

2002-01-01

Full Text Available Purpose: To describe a case of persistent retinopathy after bone marrow transplantation in the absence of radiation therapy. Methods: Case Report. Results: A 42 year-old man developed bilateral visual loss 15 months after receiving a bone marrow transplant for acute leukemia. The patient was treated with a high dose of cyclosporin A and oral corticosteroids. No radiation therapy was given. Late-onset, multiple, bilateral cotton-wool spots developed 15 months after the bone marrow transplantation and still persist. After three years other cotton-wool spots arose in the absence of any immunosuppressive therapy. Conclusions: Bone marrow transplantation microvasculopathy of the retina may be related to certain combinations of chemotherapy drugs or immunosuppression itself and may persist in the absence of these immunosuppressive drugs.

Hot Spot Removal System: System description

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-09-01

Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System`s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section.

Hot Spot Removal System: System description

International Nuclear Information System (INIS)

1997-09-01

Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System''s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section

Effects of leaf movement on leaf temperature, transpiration and radiation interception in soybean under water stress conditions

International Nuclear Information System (INIS)

Isoda, A.; Wang, P.

2001-01-01

Varietal differences in leaf movement were examined in terms of radiation interception, leaf temperature and transpiration under water stressed conditions. Five cultivars (Qindou 7232, Gaofei 16, Dongnong 87 - 138, 8285 - 8 and 8874) were grown in a concrete frame field in Xinjiang, China. Irrigation treatments (irrigation and no irrigation) were made from the flowering to the pod filling stage. A leaflet in the uppermost layer of the canopy was restrained horizontally. Leaf temperatures, transpiration rate (stem sap flow rate of the main stem per unit leaf area) and intercepted radiation of each leaflet were measured. There were greater varietal differences in leaf movement, leaf temperature and transpiration rate. Leaf temperature seemed to be adjusted by leaf movement and transpiration. The extent to which is adjusted by leaf movement and transpiration differed among the cultivars; leaf temperature was influenced mainly by leaf movement for Gaofei 16 and Dongnong 87 - 138, mainly by transpiration for Qindou 7232 and 8874, and by both for 8285 - 8. Intercepted radiation in the upper two layers of the canopy (20 cm from the uppermost) was greater in the irrigated plot, although the mean values of total leaflets of the irrigated plot were not different as compared to the non-irrigated plot. Although paraheliotropic leaf movement decreased radiation interception, it offers some possibilities for the improvement in radiation penetration within a dense canopy. Cumulated amount of transpiration during a day was compared between the restrained-leaf and the non-leaf-restrained plants in 8874. Paraheliotropic leaf movement reduced water loss by 23% in the irrigated and 71% in the non-irrigated plots

Rocky Mountain Spotted Fever

Science.gov (United States)

... with facebook share with twitter share with linkedin Rocky Mountain Spotted Fever Credit: CDC A male cayenne tick, Amblyomma cajennense, ... and New Mexico. Why Is the Study of Rocky Mountain Spotted Fever a Priority for NIAID? Tickborne diseases are becoming ...

Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data

International Nuclear Information System (INIS)

Bailey, Brian N; Mahaffee, Walter F

2017-01-01

The rapid evolution of high performance computing technology has allowed for the development of extremely detailed models of the urban and natural environment. Although models can now represent sub-meter-scale variability in environmental geometry, model users are often unable to specify the geometry of real domains at this scale given available measurements. An emerging technology in this field has been the use of terrestrial LiDAR scanning data to rapidly measure the three-dimensional geometry of trees, such as the distribution of leaf area. However, current LiDAR methods suffer from the limitation that they require detailed knowledge of leaf orientation in order to translate projected leaf area into actual leaf area. Common methods for measuring leaf orientation are often tedious or inaccurate, which places constraints on the LiDAR measurement technique. This work presents a new method to simultaneously measure leaf orientation and leaf area within an arbitrarily defined volume using terrestrial LiDAR data. The novelty of the method lies in the direct measurement of the fraction of projected leaf area G from the LiDAR data which is required to relate projected leaf area to total leaf area, and in the new way in which radiation transfer theory is used to calculate leaf area from the LiDAR data. The method was validated by comparing LiDAR-measured leaf area to (1) ‘synthetic’ or computer-generated LiDAR data where the exact area was known, and (2) direct measurements of leaf area in the field using destructive sampling. Overall, agreement between the LiDAR and reference measurements was very good, showing a normalized root-mean-squared-error of about 15% for the synthetic tests, and 13% in the field. (paper)

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

Directory of Open Access Journals (Sweden)

Van Bael Sunshine A

2012-11-01

Full Text Available Abstract 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.

Laser Pyrometer For Spot Temperature Measurements

Science.gov (United States)

Elleman, D. D.; Allen, J. L.; Lee, M. C.

1988-01-01

Laser pyrometer makes temperature map by scanning measuring spot across target. Scanning laser pyrometer passively measures radiation emitted by scanned spot on target and calibrated by similar passive measurement on blackbody of known temperature. Laser beam turned on for active measurements of reflectances of target spot and reflectance standard. From measurements, temperature of target spot inferred. Pyrometer useful for non-contact measurement of temperature distributions in processing of materials.

Easy Leaf Area: Automated Digital Image Analysis for Rapid and Accurate Measurement of Leaf Area

Directory of Open Access Journals (Sweden)

Hsien Ming Easlon

2014-07-01

Full Text Available Premise of the study: Measurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. Methods and Results: Easy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. Conclusions: Easy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images.

Automated Leaf Tracking using Multi-view Image Sequences of Maize Plants for Leaf-growth Monitoring

Science.gov (United States)

Das Choudhury, S.; Awada, T.; Samal, A.; Stoerger, V.; Bashyam, S.

2017-12-01

Extraction of phenotypes with botanical importance by analyzing plant image sequences has the desirable advantages of non-destructive temporal phenotypic measurements of a large number of plants with little or no manual intervention in a relatively short period of time. The health of a plant is best interpreted by the emergence timing and temporal growth of individual leaves. For automated leaf growth monitoring, it is essential to track each leaf throughout the life cycle of the plant. Plants are constantly changing organisms with increasing complexity in architecture due to variations in self-occlusions and phyllotaxy, i.e., arrangements of leaves around the stem. The leaf cross-overs pose challenges to accurately track each leaf using single view image sequence. Thus, we introduce a novel automated leaf tracking algorithm using a graph theoretic approach by multi-view image sequence analysis based on the determination of leaf-tips and leaf-junctions in the 3D space. The basis of the leaf tracking algorithm is: the leaves emerge using bottom-up approach in the case of a maize plant, and the direction of leaf emergence strictly alternates in terms of direction. The algorithm involves labeling of the individual parts of a plant, i.e., leaves and stem, following graphical representation of the plant skeleton, i.e., one-pixel wide connected line obtained from the binary image. The length of the leaf is measured by the number of pixels in the leaf skeleton. To evaluate the performance of the algorithm, a benchmark dataset is indispensable. Thus, we publicly release University of Nebraska-Lincoln Component Plant Phenotyping dataset-2 (UNL-CPPD-2) consisting of images of the 20 maize plants captured by visible light camera of the Lemnatec Scanalyzer 3D high throughout plant phenotyping facility once daily for 60 days from 10 different views. The dataset is aimed to facilitate the development and evaluation of leaf tracking algorithms and their uniform comparisons.

Resistance Spot Welding of dissimilar Steels

Directory of Open Access Journals (Sweden)

Ladislav Kolařík

2012-01-01

Full Text Available This paper presents an analysis of the properties of resistance spot welds between low carbon steel and austenitic CrNi stainless steel. The thickness of the welded dissimilar materials was 2 mm. A DeltaSpot welding gun with a process tape was used for welding the dissimilar steels. Resistance spot welds were produced with various welding parameters (welding currents ranging from 7 to 8 kA. Light microscopy, microhardness measurements across the welded joints, and EDX analysis were used to evaluate the quality of the resistance spot welds. The results confirm the applicability of DeltaSpot welding for this combination of materials.

On the relationships between electron spot size, focal spot size, and virtual source position in Monte Carlo simulations

International Nuclear Information System (INIS)

Sterpin, E.; Chen, Y.; Lu, W.; Mackie, T. R.; Olivera, G. H.; Vynckier, S.

2011-01-01

Purpose: Every year, new radiotherapy techniques including stereotactic radiosurgery using linear accelerators give rise to new applications of Monte Carlo (MC) modeling. Accurate modeling requires knowing the size of the electron spot, one of the few parameters to tune in MC models. The resolution of integrated megavoltage imaging systems, such as the tomotherapy system, strongly depends on the photon spot size which is closely related to the electron spot. The aim of this article is to clarify the relationship between the electron spot size and the photon spot size (i.e., the focal spot size) for typical incident electron beam energies and target thicknesses. Methods: Three electron energies (3, 5.5, and 18 MeV), four electron spot sizes (FWHM=0, 0.5, 1, and 1.5 mm), and two tungsten target thicknesses (0.15 and 1 cm) were considered. The formation of the photon beam within the target was analyzed through electron energy deposition with depth, as well as photon production at several phase-space planes placed perpendicular to the beam axis, where only photons recorded for the first time were accounted for. Photon production was considered for ''newborn'' photons intersecting a 45x45 cm 2 plane at the isocenter (85 cm from source). Finally, virtual source position and ''effective'' focal spot size were computed by backprojecting all the photons from the bottom of the target intersecting a 45x45 cm 2 plane. The virtual source position and focal spot size were estimated at the plane position where the latter is minimal. Results: In the relevant case of considering only photons intersecting the 45x45 cm 2 plane, the results unambiguously showed that the effective photon spot is created within the first 0.25 mm of the target and that electron and focal spots may be assumed to be equal within 3-4%. Conclusions: In a good approximation photon spot size equals electron spot size for high energy X-ray treatments delivered by linear accelerators.

Solar 'hot spots' are still hot

Science.gov (United States)

Bai, Taeil

1990-01-01

Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22.

Measurement for the MLC leaf velocity profile by considering the leaf leakage using a radiographic film

International Nuclear Information System (INIS)

Chow, James C L; Grigorov, Grigor N

2006-01-01

A method to measure the velocity profile of a multi-leaf collimator (MLC) leaf along its travel range using a radiographic film is reported by considering the intra-leaf leakage. A specific dynamic MLC field with leaves travelling from the field edge to the isocentre line was designed. The field was used to expose a radiographic film, which was then scanned, and the dose profile along the horizontal leaf axis was measured. The velocity at a sampling point on the film can be calculated by considering the horizontal distance between the sampling point and the isocentre line, dose at the sampling point, dose rate of the linear accelerator, the total leaf travel time from the field edge to isocentre line and the pre-measured dose rate of leaf leakage. With the leaf velocities and velocity profiles for all MLC leaves measured routinely, a comprehensive and simple QA for the MLC can be set up to test the consistency of the leaf velocity performance which is essential to the IMRT delivery using a sliding window technique. (note)

In situ determination of the depuration of three- and four-ringed polycyclic aromatic hydrocarbons co-adsorbed onto mangrove leaf surfaces

International Nuclear Information System (INIS)

Sun, Haifeng; Shi, Jing; Guo, Shuai; Zhang, Yong; Duan, Lusha

2016-01-01

A dual-wavelength fiber-optic fluorimetry for the in situ simultaneous determinations of fluorene (Flu), phenanthrene (Phe) and pyrene (Pyr) adsorbed onto the leaf surfaces of living Avicennia marina (Am) seedling were developed and used to study the depuration kinetics of the three PAHs, adsorbed individually or mixed together, onto living Am leaf surfaces. Limits of detection for the in situ measurements of adsorbed Flu, Phe and Pyr were 4.62, 2.75 and 1.38 ng spot"−"1, respectively. The depuration kinetics of the three selected polycyclic aromatic hydrocarbons (PAHs) are divided into rapid and slow phases; both phases followed the same first-order kinetics with relative clearance rates of Flu > Phe > Pyr during the rapid phase, and a clearance rate order of Pyr > Flu > Phe during the slow phase. For the three PAHs co-adsorbed on living Am leaf surfaces, a significant synergistic effect was detected during the rapid phase clearance; conversely, an antagonistic effect was observed during the slow phase. However, the synergistic effect dominated during both phases of the depuration process, and the co-adsorption of PAHs promoted the clearance of all three compounds from the mangrove leaf surfaces. These findings demonstrate a novel analytical method for in situ characterization of multiple PAHs adsorbed onto the plant surfaces. - Highlights: • A novel method for the in situ determination of multi-component PAHs was developed. • Synergistic and antagonistic effects separately occurred over rapid and slow phases. • The clearance of all three PAHs from leaf surfaces was promoted by co-adsorption. - The co-adsorption of PAHs promoted the depuration of all three compounds from the mangrove leaf surfaces.

Inter-annual variation in the response of leaf-out onset to soil moisture increase in a teak plantation in northern Thailand.

Science.gov (United States)

Yoshifuji, Natsuko; Igarashi, Yasunori; Tanaka, Nobuaki; Tanaka, Katsunori; Sato, Takanori; Tantasirin, Chatchai; Suzuki, Masakazu

2014-11-01

To understand the impact of inter-annual climate change on vegetation-atmosphere mass and energy exchanges, it has become necessary to explore changes in leaf-out onset in response to climatic fluctuations. We examined the response of leaf-out and transpiration onset dates to soil moisture in a teak plantation in northern Thailand based on a 12-year leaf area index and sap flow measurements. The date of leaf-out and transpiration onset varied between years by up to 40 days, and depended on the initial date when the relative extractable water in a soil layer of 0-0.6 m (Θ) was greater than 0.2 being consistent with our previous results. Our new finding is that the delay in leaf-out and transpiration onset relative to the initial date when Θ > 0.2 increases linearly as the initial date on which Θ > 0.2 becomes earlier. The delay spans about 20 days in years when Θ > 0.2 occurs in March (the late dry season)-much earlier than usual because of heavy pre-monsoon rainfalls-while there is little delay in years when Θ > 0.2 occurs in May. This delay indicates the influence of additional factors on leaf-out onset, which controls the delay in the response of leaf-out to soil moisture increase. The results increased our knowledge about the pattern and extent of the changes in leaf phenology that occur in response to the inter-annual climate variation in tropical regions, where, in particular, such research is needed.

Arc cathode spots

International Nuclear Information System (INIS)

Schrade, H.O.

1989-01-01

Arc spots are usually highly unstable and jump statistically over the cathode surface. In a magnetic field parallel to the surface, preferably they move in the retrograde direction; i.e., opposite to the Lorentzian rule. If the field is inclined with respect to the surface, the spots drift away at a certain angle with respect to the proper retrograde direction (Robson drift motion). These well-known phenomena are explained by one stability theory

7 CFR 28.413 - Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Middling Light Spotted Color. 28.413 Section 28.413... Spotted Color. Middling Light Spotted Color is color which in spot or color, or both, is between Middling Color and Middling Spotted Color. ...

S Abelm okra l Screen mosch leaf cu field c ing of hus cal url and ...

African Journals Online (AJOL)

sunny

y okra has a reas late okra. 1977; Nwoke. 1998). World uit-vegetable on License 4.0 y n or a .... nineties while the substantive work was carried out in the Department of Crop ... measuring 6.5 x 6.0 m for the protected plots and 7.5 x 7.0 m for ..... gen the oth spe the obv imp. 26 Afr. J igure 3. Chron. Okra Leaf curl a urling and ...

Geometric leaf placement strategies

International Nuclear Information System (INIS)

Fenwick, J D; Temple, S W P; Clements, R W; Lawrence, G P; Mayles, H M O; Mayles, W P M

2004-01-01

Geometric leaf placement strategies for multileaf collimators (MLCs) typically involve the expansion of the beam's-eye-view contour of a target by a uniform MLC margin, followed by movement of the leaves until some point on each leaf end touches the expanded contour. Film-based dose-distribution measurements have been made to determine appropriate MLC margins-characterized through an index d 90 -for multileaves set using one particular strategy to straight lines lying at various angles to the direction of leaf travel. Simple trigonometric relationships exist between different geometric leaf placement strategies and are used to generalize the results of the film work into d 90 values for several different strategies. Measured d 90 values vary both with angle and leaf placement strategy. A model has been derived that explains and describes quite well the observed variations of d 90 with angle. The d 90 angular variations of the strategies studied differ substantially, and geometric and dosimetric reasoning suggests that the best strategy is the one with the least angular variation. Using this criterion, the best straightforwardly implementable strategy studied is a 'touch circle' approach for which semicircles are imagined to be inscribed within leaf ends, the leaves being moved until the semicircles just touch the expanded target outline

Solar hot spots are still hot

International Nuclear Information System (INIS)

Bai, T.

1990-01-01

Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22. 14 refs

7 CFR 28.423 - Middling Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Middling Spotted Color. 28.423 Section 28.423... REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Spotted Cotton § 28.423 Middling Spotted Color. Middling Spotted Color is color which is within the range represented by a set of samples in the custody of...

Apparent over-investment in leaf venation relaxes leaf morphological constraints on photosynthesis in arid habitats

Science.gov (United States)

de Boer, Hugo; Drake, Paul; Veneklaas, Erik

2017-04-01

The close relationship between leaf water status and stomatal conductance implies that the hydraulic architecture of leaves poses an important constraint on transpiration, specifically in arid environments with high evaporative demands. However, it remains uncertain how morphological, hydraulic and photosynthetic traits are coordinated to achieve optimal leaf functioning in arid environments. Critical is that leaf veins supply the mesophyll with water that evaporates when stomata are open to allow CO2 uptake for photosynthesis. Theoretical analyses suggest that water is optimally distributed in the mesophyll when the lateral distance between veins (dx) is equal to the distance from these veins to the epidermis (dy), expressed as dx:dy≈1. Although this theory is supported by observations on many derived angiosperms, we hypothesize that plants in arid environments may reduce dx:dy below unity owing to climate-specific functional adaptations of increased leaf thickness and increased vein density. To test our hypothesis we assembled leaf hydraulic, morphological and photosynthetic traits of 68 species from the Eucalyptus and Corymbia genera (termed eucalypts) along an aridity gradient in southwestern Australia. We inferred the potential gas exchange advantage of reducing dx beyond dy using a model that links leaf morphology and hydraulics to photosynthesis. Our observations reveal that eucalypts in arid environments have thick amphistomatous leaves with high vein densities, resulting in dx:dy ratios that range from 1.6 to 0.15 along the aridity gradient. Our model suggests that as leaves become thicker, the effect of reducing dx beyond dy is to offset the reduction in leaf gas exchange that would result from maintaining dx:dy at unity. This apparent over-investment in leaf venation may be explained from the selective pressure of aridity, under which traits associated with long leaf lifespan, high hydraulic and thermal capacitances, and high potential rates of leaf

Creating 13C- and 15N-enriched tree leaf litter for decomposition experiments

Science.gov (United States)

Szlavecz, K. A.; Pitz, S.; Chang, C.; Bernard, M.

2013-12-01

Labeling plant material with heavy isotopes of carbon and nitrogen can produce a traceable nutrient signal that can be followed into the different trophic levels and decomposer food web. We treated 60 tree saplings with 13C-enriched CO2 gas and 15N-enriched ammonium nitrate over a three-month period to create dually-labeled plant material for future decomposition experiments. The trees included both early (Red maple, Sweetgum, Tulip poplar) and late (American beech, White oak) successional deciduous tree species, and a conifer, White pine. We constructed a 2.4 m × 2.4 m × 2.4 m environmental chamber that was climate-controlled using an air conditioning system. An Arduino microcontroller interfaced with a Vaisala GMP343 CO2 probe maintained a CO2 concentration between 500-520 ppm by controlling a solenoid valve on the CO2 tank regulator. The trees were placed into the chamber in August 2012 and remained until senescence unless they were lost to death or disease. Ammonium nitrate was added twice, in September and October. Leaf samples were collected prior to the start of the experiment and after senescence, whereas root samples were collected only in December. Samples were dried, ground and analyzed using an isotope ratio mass spectrometer. American beech and White oak had 40% mortality, and 34% of tulip poplar trees were removed because of powdery mildew overgrowth or death. Most tulip poplar trees exhibited a second leaf out following senescence in late September. Nearly 1 kg of litter was produced with tulip poplar representing over half of the total mass. Levels of enrichment varied greatly by species. Beech (-14.2‰) and White oak (-4.8‰) had low levels of enrichment in comparison to early successional species such as Sweetgum (41.7‰) and Tulip poplar (30.7‰ [first leaf fall] and 238.0‰ [second leaf fall]). Leaf enrichment with 15N followed a similar pattern, though it was achieved at a higher level with δ15N values varying from 271.6‰ to 1354.2�

Resistance to stem canker, frogeye leaf spot and powdery mildew of soybean lines lacking lipoxigenases in the seeds Resistência ao cancro-da-haste, à cercosporiose e ao oídio de linhagens de soja sem lipoxigenases nas sementes

Directory of Open Access Journals (Sweden)

Carlos Alberto Osório Martins

2002-12-01

Full Text Available The soybean [Glycine max (L. Merrill] crop holds a prominent position in the Brazilian economy because of the extension of the planted area and volume of grain production, but the beany flavor has been a limiting factor for soybean derivatives consumption by western population. This flavor is produced mainly by action of lipoxygenase enzymes (Lox1, Lox2 and Lox3, present in some commercial varieties. The genetic elimination of the alleles that codify these enzymes is the most appropriate way to avoid problems associated to this deleterious flavor. To elucidate the effect of seed lipoxygenase elimination on the resistance to plant pathogens, normal varieties of soybean (FT-Cristalina RCH, Doko RC and IAC-12 and their backcross-derived lines, both with the three lipoxygenases present in their seeds (triple-positive, TP and without the three lipoxygenases (triple-null, TN, were tested for their resistance to stem canker (Diaporthe phaseolorum f.sp. meridionalis, frogeye leaf spot (Cercospora sojina Hara, and powdery mildew (Microsphaera diffusa Cke. & Pk.. All genetic materials studied were resistant to stem canker. FT-Cristalina RCH and Doko-RC and their TP and TN lines were resistant to frogeye leaf spot. IAC-12 and its derived lines not only presented a higher disease index, but also the derived lines, TP and TN, were more susceptible, indicating the loss of genes for disease resistance in the backcrosses. There was no association between the elimination of lipoxygenases from the seeds with the resistance to frogeye leaf spot. In relation to the powdery mildew, TP or TN lines presented similar or higher resistance than their respective recurrent parents whose susceptibility appeared in the following order: IAC-12, less susceptible, Doko-RC, intermediate and FT-Cristalina RCH, more susceptible.A cultura da soja [Glycine max (L. Merrill] ocupa lugar de destaque na economia brasileira, tanto em termos de área plantada, quanto de produção de gr

Improved simulation method of automotive spot weld failure with an account of the mechanical properties of spot welds

Science.gov (United States)

Wu, H.; Meng, X. M.; Fang, R.; Huang, Y. F.; Zhan, S.

2017-12-01

In this paper, the microstructure and mechanical properties of spot weld were studied, the hardness of nugget and heat affected zone (HAZ) were also tested by metallographic microscope and microhardness tester. The strength of the spot weld with the different parts' area has been characterized. According to the experiments result, CAE model of spot weld with HAZ structure was established, and simulation results of different lap-shear CAE models were analyzed. The results show that the spot weld model which contained the HAZ has good performance and more suitable for engineering application in spot weld simulation.

TV spots' impact.

Science.gov (United States)

El-bakly, S

1994-09-01

The Information, Education and Communication (IEC) Center of the State Information Service was established in 1979 for the purpose of providing information to the people on the population issue. The Ministry of Information has accorded the State Information Service free TV and radio air time for family planning dramas and spots. In the early years information campaigns were organized to make people aware of the population problem by slogans, songs, and cartoons. Around 1984 misconceptions about family planning and contraceptives were attacked through a number of TV and radio spots. A few years later 21 spots on specific contraceptive methods were broadcast which were aired for three years over 3000 times. They were extremely successful. The impact of these TV spots was one of the major reasons why the contraceptive prevalence rate increased from 30% in 1984 to 38% in 1988 and 47% in 1992. Spots were also broadcast about the social implications of large families. The TV soap opera "And The Nile Flows On", with the family planning message interwoven into it, was very well received by the target audience. A program entitled "Wedding of the Month" features couples who know family planning well. The most successful radio program is a 15-20 minute long quiz show for residents of the villages where the Select Villages Project is being implemented. The State Information Service has 60 local information centers in the 26 governorates of Egypt that make plans for the family planning campaign. In 1992 the Minya Initiative, a family planning project was implemented in the Minya Governorate. As a result, the contraceptive prevalence rate rose from 22% to 30% over 18 months. A new project, the Select Village Project, was developed in 1993 that replicates the Minya Initiative on the village level in other governorates. This new project that was implemented in sixteen governorates.

Black-spot poison ivy.

Science.gov (United States)

Schram, Sarah E; Willey, Andrea; Lee, Peter K; Bohjanen, Kimberly A; Warshaw, Erin M

2008-01-01

In black-spot poison ivy dermatitis, a black lacquerlike substance forms on the skin when poison ivy resin is exposed to air. Although the Toxicodendron group of plants is estimated to be the most common cause of allergic contact dermatitis in the United States, black-spot poison ivy dermatitis is relatively rare.

Light curve analysis of the late type binary V523 Cassiopeiae

Directory of Open Access Journals (Sweden)

Latković O.

2009-01-01

Full Text Available We present the analysis of V and R light curves of the late type contact binary V523 Cas for the season of 2006. These observations make part of the monitoring program aimed at studying the long-term light curve variability in this system. Our results confirm that the system is in an over contact configuration, and include a bright spot in the neck region of the cooler and larger primary. We compare these results with the previous solution, obtained for the season 2005 dataset and discuss the differences.

Computational prediction of protein hot spot residues.

Science.gov (United States)

Morrow, John Kenneth; Zhang, Shuxing

2012-01-01

Most biological processes involve multiple proteins interacting with each other. It has been recently discovered that certain residues in these protein-protein interactions, which are called hot spots, contribute more significantly to binding affinity than others. Hot spot residues have unique and diverse energetic properties that make them challenging yet important targets in the modulation of protein-protein complexes. Design of therapeutic agents that interact with hot spot residues has proven to be a valid methodology in disrupting unwanted protein-protein interactions. Using biological methods to determine which residues are hot spots can be costly and time consuming. Recent advances in computational approaches to predict hot spots have incorporated a myriad of features, and have shown increasing predictive successes. Here we review the state of knowledge around protein-protein interactions, hot spots, and give an overview of multiple in silico prediction techniques of hot spot residues.

NARROW LEAF 7 controls leaf shape mediated by auxin in rice

NARCIS (Netherlands)

Fujino, Kenji; Matsuda, Yasuyuki; Ozawa, Kenjirou; Nishimura, Takeshi; Koshiba, Tomokazu; Fraaije, Marco W.; Sekiguchi, Hiroshi

Elucidation of the genetic basis of the control of leaf shape could be of use in the manipulation of crop traits, leading to more stable and increased crop production. To improve our understanding of the process controlling leaf shape, we identified a mutant gene in rice that causes a significant

7 CFR 1421.11 - Spot checks.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Spot checks. 1421.11 Section 1421.11 Agriculture... ASSISTANCE LOANS AND LOAN DEFICIENCY PAYMENTS FOR 2008 THROUGH 2012 General § 1421.11 Spot checks. (a) CCC... CCC access to the farm and storage facility as necessary to conduct collateral inspections, or “spot...

21 CFR 886.1435 - Maxwell spot.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Maxwell spot. 886.1435 Section 886.1435 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1435 Maxwell spot. (a) Identification. A Maxwell spot is an AC...

Effects of slag-based silicon fertilizer on rice growth and brown-spot resistance.

Science.gov (United States)

Ning, Dongfeng; Song, Alin; Fan, Fenliang; Li, Zhaojun; Liang, Yongchao

2014-01-01

It is well documented that slag-based silicon fertilizers have beneficial effects on the growth and disease resistance of rice. However, their effects vary greatly with sources of slag and are closely related to availability of silicon (Si) in these materials. To date, few researches have been done to compare the differences in plant performance and disease resistance between different slag-based silicon fertilizers applied at the same rate of plant-available Si. In the present study both steel and iron slags were chosen to investigate their effects on rice growth and disease resistance under greenhouse conditions. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the effects of slags on ultrastructural changes in leaves of rice naturally infected by Bipolaris oryaze, the causal agent of brown spot. The results showed that both slag-based Si fertilizers tested significantly increased rice growth and yield, but decreased brown spot incidence, with steel slag showing a stronger effect than iron slag. The results of SEM analysis showed that application of slags led to more pronounced cell silicification in rice leaves, more silica cells, and more pronounced and larger papilla as well. The results of TEM analysis showed that mesophyll cells of slag-untreated rice leaf were disorganized, with colonization of the fungus (Bipolaris oryzae), including chloroplast degradation and cell wall alterations. The application of slag maintained mesophyll cells relatively intact and increased the thickness of silicon layer. It can be concluded that applying slag-based fertilizer to Si-deficient paddy soil is necessary for improving both rice productivity and brown spot resistance. The immobile silicon deposited in host cell walls and papillae sites is the first physical barrier for fungal penetration, while the soluble Si in the cytoplasm enhances physiological or induced resistance to fungal colonization.

Characterization and fine mapping of a light-dependent leaf lesion mimic mutant 1 in rice.

Science.gov (United States)

Wang, Jing; Ye, Bangquan; Yin, Junjie; Yuan, Can; Zhou, Xiaogang; Li, Weitao; He, Min; Wang, Jichun; Chen, Weilan; Qin, Peng; Ma, Bintian; Wang, Yuping; Li, Shigui; Chen, Xuewei

2015-12-01

Plants that spontaneously produce lesion mimics or spots, without any signs of obvious adversity, such as pesticide and mechanical damage, or pathogen infection, are so-called lesion mimic mutants (lmms). In rice, many lmms exhibit enhanced resistance to pathogens, which provides a unique opportunity to uncover the molecular mechanism underlying lmms. We isolated a rice light-dependent leaf lesion mimic mutant 1 (llm1). Lesion spots appeared in the leaves of the llm1 mutant at the tillering stage. Furthermore, the mutant llm1 had similar agronomic traits to wild type rice. Trypan blue and diamiobenzidine staining analyses revealed that the lesion spot formation on the llm1 mutant was due to programmed cell death and reactive oxygen species. The chloroplasts were severely damaged in the llm1 mutant, suggesting that chloroplast damage was associated with the formation of lesion spots in llm1. More importantly, llm1 exhibited enhanced resistance to bacterial blight pathogens within increased expression of pathogenesis related genes (PRs). Using a map-based cloning approach, we delimited the LLM1 locus to a 121-kb interval between two simple sequence repeat markers, RM17470 and RM17473, on chromosome 4. We sequenced the candidate genes on the interval and found that a base mutation had substituted adenine phosphate for thymine in the last exon of LOC_Os04g52130, which led to an amino acid change (Asp(388) to Val) in the llm1 mutant. Our investigation showed that the putative coproporphyrinogen III oxidase (CPOX) encoded by LOC_Os04g52130 was produced by LLM1 and that amino acid Asp(388) was essential for CPOX function. Our study provides the basis for further investigations into the mechanism underlying lesion mimic initiation associated with LLM1. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Late-onset Pompe disease: first clinical description in Russia

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S. S. Nikitin

2014-01-01

Full Text Available Late-onset Pompe-disease (LOPD is an adult form of the glycogenosis type II. The age of onset ranges from 1 till 75 y.o. and older. The diagnosis of LOPD is based on the presence of trunk and limb-girdle muscle weakness with hyperlordosis, respiratory failure, ocasionally accompanied by cardiomyopathy, persistent mild elevation of creatine kinase, dry blood spot test of the enzyme activity and DNA-analysis of GAA-gene. Early recognition of the LOPD and beginning of the enzyme replacement therapy is important in preventing severe motor and respiratory deficit, the patient disability and in increasing the survival in those patients.

Scaling up stomatal conductance from leaf to canopy using a dual-leaf model for estimating crop evapotranspiration.

Directory of Open Access Journals (Sweden)

Risheng Ding

Full Text Available The dual-source Shuttleworth-Wallace model has been widely used to estimate and partition crop evapotranspiration (λET. Canopy stomatal conductance (Gsc, an essential parameter of the model, is often calculated by scaling up leaf stomatal conductance, considering the canopy as one single leaf in a so-called "big-leaf" model. However, Gsc can be overestimated or underestimated depending on leaf area index level in the big-leaf model, due to a non-linear stomatal response to light. A dual-leaf model, scaling up Gsc from leaf to canopy, was developed in this study. The non-linear stomata-light relationship was incorporated by dividing the canopy into sunlit and shaded fractions and calculating each fraction separately according to absorbed irradiances. The model includes: (1 the absorbed irradiance, determined by separately integrating the sunlit and shaded leaves with consideration of both beam and diffuse radiation; (2 leaf area for the sunlit and shaded fractions; and (3 a leaf conductance model that accounts for the response of stomata to PAR, vapor pressure deficit and available soil water. In contrast to the significant errors of Gsc in the big-leaf model, the predicted Gsc using the dual-leaf model had a high degree of data-model agreement; the slope of the linear regression between daytime predictions and measurements was 1.01 (R2 = 0.98, with RMSE of 0.6120 mm s-1 for four clear-sky days in different growth stages. The estimates of half-hourly λET using the dual-source dual-leaf model (DSDL agreed well with measurements and the error was within 5% during two growing seasons of maize with differing hydrometeorological and management strategies. Moreover, the estimates of soil evaporation using the DSDL model closely matched actual measurements. Our results indicate that the DSDL model can produce more accurate estimation of Gsc and λET, compared to the big-leaf model, and thus is an effective alternative approach for estimating and

Newborn screening blood spot analysis in the UK: influence of spot size, punch location and haematocrit.

Science.gov (United States)

Lawson, A J; Bernstone, L; Hall, S K

2016-03-01

In dried blood spot analysis, punch location and variations in applied sample volume and haematocrit can produce different measured concentrations of analytes. We investigated the magnitude of these effects in newborn screening in the UK. Heparinized blood spiked with thyroid stimulating hormone (TSH), phenylalanine, tyrosine, leucine, methionine, octanoyl carnitine (C8), and immunoreactive trypsinogen (IRT) was spotted onto filter paper: (i) at a constant haematocrit of 50% at various volumes, and (ii) at a range of haematocrits using a constant volume. Subpunches (3.2 mm) of the dried blood spots were then analysed. Compared with a central punch from a 50 µL blood spot with 50% haematocrit, 10 µL spots can have significantly lower measured concentrations of all analytes, with decreases of 15% or more observed for leucine, methionine, phenylalanine, and tyrosine. Punching at the edge of a spot can increase measured concentrations up to 35%. Higher haematocrit decreased measured TSH and C8 yet increased amino acids and IRT by 15% compared with 50% haematocrit. Lower haematocrits had the opposite effect, but only with higher concentrations of some analytes. Differences in blood spot size, haematocrit and punch location substantially affect measured concentrations for analytes used in the UK newborn screening programme, and this could affect false positive and negative rates. To minimize analytical bias, these variables should be controlled or adjusted for where possible. © The Author(s) 2015.

Seasonality of Leaf Carbon Isotopic Composition and Leaf Water Isotopic Enrichment in a Mixed Evergreen Forest in Southern California

Science.gov (United States)

Santiago, L. S.; Sickman, J. O.; Goulden, M.; DeVan, C.; Pasquini, S. C.; Pivovaroff, A. L.

2011-12-01

Leaf carbon isotopic composition and leaf water isotopic enrichment reflect physiological processes and are important for linking local and regional scale processes to global patterns. We investigated how seasonality affects the isotopic composition of bulk leaf carbon, leaf sugar carbon, and leaf water hydrogen under a Mediterranean climate. Leaf and stem samples were collected monthly from four tree species (Calocedrus decurrens, Pinus lambertiana, Pinus ponderosa, and Quercus chrysolepis) at the James San Jacinto Mountain Reserve in southern California. Mean monthly bulk leaf carbon isotopic composition varied from -34.5 % in P. ponderosa to -24.7 % in P. lambertiana and became more depleted in 13C from the spring to the summer. Mean monthly leaf sugar varied from -29.3 % in P. ponderosa to -21.8 % in P. lambertiana and was enriched in 13C during the winter, spring and autumn, but depleted during the mid-summer. Leaf water hydrogen isotopic composition was 28.4 to 68.8 % more enriched in deuterium than source water and this enrichment was greater as seasonal drought progressed. These data indicate that leaf carbon and leaf water hydrogen isotopic composition provide sensitive measures that connect plant physiological processes to short-term climatic variability.

Alfalfa leaf meal in wintering beef cow diets. Quarterly report, July 1, 1997--September 30, 1997

Energy Technology Data Exchange (ETDEWEB)

Zehnder, C.M.; Hall, J.M.; Brown, D.B.; DiCostanzo, A.

1998-06-01

One hundred dry pregnant cows (1389 lb) and twenty-four pregnant heifers (1034 lb) were assigned by calving date and body condition to one of four dietary treatments for a wintering period during their late gestation. Dietary treatments consisted of supplementing crude protein (CP) at 100 % or 120 % of the recommended intake using either soybean meal or alfalfa leaf meal (ALM) as the supplemental protein source. Cows were group fed (two replicate pens/treatment) while heifers were individually fed for the duration of the study. The study lasted 70 (early) or 85 (late) days for cows and ended when the first cow in each replicate calved. For heifers, the study lasted for 100 days and ended accordingly when each heifer calved. Heifers fed ALM had consumed less (P < .05) hay and corn dry matter (DM). Overall diet DM intakes were unaffected (P > .05) by protein source. Feeding 120 % of recommended protein (2.38 vs 2.07 lb/day) to heifers increased (P < .05) their rate of gain by almost .5 lb/head/day. Cows fed ALM had faster (P < .05) rates of gain when gain was measured 22 days before calving. Once cows calved, weight change was similar (P > .05) for each protein source. However, cows fed alfalfa leaf meal consumed more (P = .054) total dry matter (DM). Calving traits were not affected by protein source or intake. Wintering heifers or cows on ALM-based supplements had no detrimental effect on performance of heifers or cows or their calves at birth. Additional protein may be required by heifers to ensure that they continue gaining weight during late gestation.

Leaf sequencing algorithms for segmented multileaf collimation

International Nuclear Information System (INIS)

Kamath, Srijit; Sahni, Sartaj; Li, Jonathan; Palta, Jatinder; Ranka, Sanjay

2003-01-01

The delivery of intensity-modulated radiation therapy (IMRT) with a multileaf collimator (MLC) requires the conversion of a radiation 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 map generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. Optimization of the leaf sequencing algorithm has been the subject of several recent investigations. In this work, we present a systematic study of the optimization of leaf sequencing algorithms for segmental multileaf collimator beam delivery and provide rigorous mathematical proofs of optimized leaf sequence settings in terms of monitor unit (MU) efficiency under most common leaf movement constraints that include minimum leaf separation constraint and leaf interdigitation constraint. Our analytical analysis shows that leaf sequencing based on unidirectional movement of the MLC leaves is as MU efficient as bidirectional movement of the MLC leaves

Leaf sequencing algorithms for segmented multileaf collimation

Energy Technology Data Exchange (ETDEWEB)

Kamath, Srijit [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Sahni, Sartaj [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Li, Jonathan [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Palta, Jatinder [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Ranka, Sanjay [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States)

2003-02-07

The delivery of intensity-modulated radiation therapy (IMRT) with a multileaf collimator (MLC) requires the conversion of a radiation 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 map generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. Optimization of the leaf sequencing algorithm has been the subject of several recent investigations. In this work, we present a systematic study of the optimization of leaf sequencing algorithms for segmental multileaf collimator beam delivery and provide rigorous mathematical proofs of optimized leaf sequence settings in terms of monitor unit (MU) efficiency under most common leaf movement constraints that include minimum leaf separation constraint and leaf interdigitation constraint. Our analytical analysis shows that leaf sequencing based on unidirectional movement of the MLC leaves is as MU efficient as bidirectional movement of the MLC leaves.

Study on creation of an indocalamus leaf flavor

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Guangyong ZHU

2015-01-01

Full Text Available AbstractFlavors represent a small but significant segment of food industry. Sensory characteristics play an important role in the process of consumer acceptance and preference. Indocalamus leaf takes on a pleasant odor and indocalamus leaf flavor can be used in many products. However, indocalamus leaf flavor formula has not been reported. Therefore, developing an indocalamus leaf flavor is of significant interests. Note is a distinct flavor or odor characteristic. This paper concentrates on preparation and creation of indocalamus leaf flavor according to the notes of indocalamus leaf. The notes were obtained by smelling indocalamus leaf, and the results showed that the notes of indocalamus leaf flavor can be classified as: green-leafy note, sweet note, beany note, aldehydic note, waxy note, woody note, roast note, creamy note, and nutty note. According to the notes of indocalamus leaf odor, a typical indocalamus leaf flavor formula was obtained. The indocalamus leaf flavor blended is pleasant, harmonious, and has characteristics of indocalamus leaf odor.

Md-miR156ab and Md-miR395 Target WRKY Transcription Factors to Influence Apple Resistance to Leaf Spot Disease.

Science.gov (United States)

Zhang, Qiulei; Li, Yang; Zhang, Yi; Wu, Chuanbao; Wang, Shengnan; Hao, Li; Wang, Shengyuan; Li, Tianzhong

2017-01-01

MicroRNAs (miRNAs) are key regulators of gene expression that post-transcriptionally regulate transcription factors involved in plant physiological activities. Little is known about the effects of miRNAs in disease resistance in apple ( Malus × domestica ). We globally profiled miRNAs in the apple cultivar Golden Delicious (GD) infected or not with the apple leaf spot fungus Alternaria alternaria f. sp. mali (ALT1), and identified 58 miRNAs that exhibited more than a 2-fold upregulation upon ALT1 infection. We identified a pair of miRNAs that target protein-coding genes involved in the defense response against fungal pathogens; Md-miR156ab targets a novel WRKY transcription factor, MdWRKYN1, which harbors a TIR and a WRKY domain. Md-miR395 targets another transcription factor, MdWRKY26, which contains two WRKY domains. Real-time PCR analysis showed that Md-miR156ab and Md-miR395 levels increased, while MdWRKYN1 and MdWRKY26 expression decreased in ALT1-inoculated GD leaves; furthermore, the overexpression of Md-miR156ab and Md-miR395 resulted in a significant reduction in MdWRKYN1 and MdWRKY26 expression. To investigate whether these miRNAs and their targets play a crucial role in plant defense, we overexpressed MdWRKYN1 or knocked down Md-miR156ab activity, which in both cases enhanced the disease resistance of the plants by upregulating the expression of the WRKY-regulated pathogenesis-related (PR) protein-encoding genes MdPR3-1, MdPR3-2, MdPR4, MdPR5, MdPR10-1 , and MdPR10-2 . In a similar analysis, we overexpressed MdWRKY26 or suppressed Md-miR395 activity, and found that many PR protein-encoding genes were also regulated by MdWRKY26 . In GD, ALT-induced Md-miR156ab and Md-miR395 suppress MdWRKYN1 and MdWRKY26 expression, thereby decreasing the expression of some PR genes, and resulting in susceptibility to ALT1.

Identification of gibberellin acid-responsive proteins in rice leaf sheath using proteomics.

Science.gov (United States)

Gu, Jia-Yu; Wang, Ye; Zhang, Xu; Zhang, Shi-Hua; Gao, Yin; An, Cheng-Cai

2010-06-01

The phytohormone gibberellin acid (GA) controls many aspects of plant development. In this study, we identified proteins that are differentially expressed between the rice (Oryza sativa L.) GA-deficient cultivar, Aijiaonante, and its parental line, Nante. Proteins were extracted from rice leaf sheath and examined by 2DGE. Among more than 1200 protein spots reproducibly detected on each gel, 29 were found to be highly up-regulated by GAs in Nante, and 6 were down-regulated by GAs in Aijiaonante. These 35 proteins were identified by MALDI-TOF MS and were classified into three groups based on their putative function in metabolism, stress/defense processes and signal transduction. These data suggest that metabolic pathways are the main target of regulation by GAs during rice development. Our results provide new information about the involvement of GAs in rice development.

The dosimetric impact of leaf interdigitation and leaf width on VMAT treatment planning in Pinnacle: comparing Pareto fronts

International Nuclear Information System (INIS)

Van Kesteren, Z; Janssen, T M; Damen, E; Van Vliet-Vroegindeweij, C

2012-01-01

To evaluate in an objective way the effect of leaf interdigitation and leaf width on volumetric modulated arc therapy plans in Pinnacle. Three multileaf collimators (MLCs) were modeled: two 10 mm leaf width MLCs, with and without interdigitating leafs, and a 5 mm leaf width MLC with interdigitating leafs. Three rectum patients and three prostate patients were used for the planning study. In order to compare treatment techniques in an objective way, a Pareto front comparison was carried out. 200 plans were generated in an automated way, per patient per MLC model, resulting in a total of 3600 plans. From these plans, Pareto-optimal plans were selected which were evaluated for various dosimetric variables. The capability of leaf interdigitation showed little dosimetric impact on the treatment plans, when comparing the 10 mm leaf width MLC with and without leaf interdigitation. When comparing the 10 mm leaf width MLC with the 5 mm leaf width MLC, both with interdigitating leafs, improvement in plan quality was observed. For both patient groups, the integral dose was reduced by 0.6 J for the thin MLC. For the prostate patients, the mean dose to the anal sphincter was reduced by 1.8 Gy and the conformity of the V 95% was reduced by 0.02 using the thin MLC. The V 65% of the rectum was reduced by 0.1% and the dose homogeneity with 1.5%. For rectum patients, the mean dose to the bowel was reduced by 1.4 Gy and the mean dose to the bladder with 0.8 Gy for the thin MLC. The conformity of the V 95% was equivalent for the 10 and 5 mm leaf width MLCs for the rectum patients. We have objectively compared three types of MLCs in a planning study for prostate and rectum patients by analyzing Pareto-optimal plans which were generated in an automated way. Interdigitation of MLC leafs does not generate better plans using the SmartArc algorithm in Pinnacle. Changing the MLC leaf width from 10 to 5 mm generates better treatment plans although the clinical relevance remains to be proven

The dosimetric impact of leaf interdigitation and leaf width on VMAT treatment planning in Pinnacle: comparing Pareto fronts.

Science.gov (United States)

van Kesteren, Z; Janssen, T M; Damen, E; van Vliet-Vroegindeweij, C

2012-05-21

To evaluate in an objective way the effect of leaf interdigitation and leaf width on volumetric modulated arc therapy plans in Pinnacle. Three multileaf collimators (MLCs) were modeled: two 10 mm leaf width MLCs, with and without interdigitating leafs, and a 5 mm leaf width MLC with interdigitating leafs. Three rectum patients and three prostate patients were used for the planning study. In order to compare treatment techniques in an objective way, a Pareto front comparison was carried out. 200 plans were generated in an automated way, per patient per MLC model, resulting in a total of 3600 plans. From these plans, Pareto-optimal plans were selected which were evaluated for various dosimetric variables. The capability of leaf interdigitation showed little dosimetric impact on the treatment plans, when comparing the 10 mm leaf width MLC with and without leaf interdigitation. When comparing the 10 mm leaf width MLC with the 5 mm leaf width MLC, both with interdigitating leafs, improvement in plan quality was observed. For both patient groups, the integral dose was reduced by 0.6 J for the thin MLC. For the prostate patients, the mean dose to the anal sphincter was reduced by 1.8 Gy and the conformity of the V(95%) was reduced by 0.02 using the thin MLC. The V(65%) of the rectum was reduced by 0.1% and the dose homogeneity with 1.5%. For rectum patients, the mean dose to the bowel was reduced by 1.4 Gy and the mean dose to the bladder with 0.8 Gy for the thin MLC. The conformity of the V(95%) was equivalent for the 10 and 5 mm leaf width MLCs for the rectum patients. We have objectively compared three types of MLCs in a planning study for prostate and rectum patients by analyzing Pareto-optimal plans which were generated in an automated way. Interdigitation of MLC leafs does not generate better plans using the SmartArc algorithm in Pinnacle. Changing the MLC leaf width from 10 to 5 mm generates better treatment plans although the clinical relevance remains

KEMAMPUAN BAKTERI ENDOFIT TANAMAN SEMANGKA DALAM MENEKAN PERKEMBANGAN PENYAKIT BERCAK DAUN YANG DISEBABKAN OLEH JAMUR COLLETOTRICHUM SP.

Directory of Open Access Journals (Sweden)

Eryna Elfasari Rangkuti

2015-06-01

Full Text Available Ability of watermelon endophytic bacteria to suppress development of leaf spot disease caused by Colletotrichum sp.  A studi on assay of endophytic bacteria to control Colletotrichum sp., causal agent of leaf spot disease on watermelon, was conducted. Colletotrichum sp. was isolated from infected leaf of leaf spot disease, while endophytic bacteria were isolated from stem, leaf, and root of watermelon healthy plant. Antagonistic assay was conducted by dual culture method. Hyphal abnormalities as a result of antagonistic assay was observed using light microscope. To determine the ability of endophytic bacterial isolates to control leaf spot disease, watermelon seeds were treated by dipping the seed in endophytic bacterial suspension. Seven endophytic bacterial isolates showed to inhibit Colletotrichum sp. to some extent. Two isolates DS 01 and BS 01 showed relatively high inhibition zone compared to others, therefore were choosen for further study. Abnormal hyphae such as broken, lysis, twisted, curled, and swollen hyphae were recorded as the result of antagonistic assay. Watermelon seed treatment revealed that dipping the seed in endophytic bacterial suspension of DS 01 and BS 01 reduced leaf spot disease to 12 and 24%, but inhibited seed growth by 12% and 44%, respectively. It seemed that all treatments showed to reduce seedling performance i.e seedling height, leaf number, and dry weight, compared to that of (- control. DS 01 however seemed to increase dry weight of watermelon plants.

DIFFERENCES IN LEAF GAS EXCHANGE AND LEAF CHARACTERISTICS BETWEEN TWO ALMOND CULTIVARS

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George D. Nanos

2013-12-01

Full Text Available Leaf chlorophyll content, specific leaf weight (SLW, photosynthetic and transpiration rates, stomatal functioning, water use efficiency and quantum yield were assessed during the kernel filling period for two consecutive years in order to understand tissue-centered physiological profile differences between two commercial almond cultivars, ‘Ferragnès’ and ‘Texas’. Similar SLWs were observed on the studied cultivars; however, chlorophyll content, net photosynthetic and transpiration rates and stomatal functioning demonstrated statistically significant differences. In both cultivars, an overall decline in the examined parameters towards fruit maturation (i.e. end of the summer was recorded. ‘Ferragnès’ leaves were found to be more efficient in leaf photosynthesis related performance during kernel filling, when irrigated sufficiently, in comparison to ‘Texas’ leaves. Low average values of leaf conductance during summer in ‘Texas’ leaves revealed its potential for adaptation in cool climates and increased carbon assimilation therein for high kernel yield.

Advances in spot curing technology

International Nuclear Information System (INIS)

Burga, R.

1999-01-01

A brief review of spot curing technology was presented. The process which a spot of energy of a specific wavelength bandwidth and irradiance is used to cause a coating, encapsulant or adhesive to change from a liquid to a solid state

The fractal nature of vacuum arc cathode spots

International Nuclear Information System (INIS)

Anders, Andre

2005-01-01

Cathode spot phenomena show many features of fractals, for example self-similar patterns in the emitted light and arc erosion traces. Although there have been hints on the fractal nature of cathode spots in the literature, the fractal approach to spot interpretation is underutilized. In this work, a brief review of spot properties is given, touching the differences between spot type 1 (on cathodes surfaces with dielectric layers) and spot type 2 (on metallic, clean surfaces) as well as the known spot fragment or cell structure. The basic properties of self-similarity, power laws, random colored noise, and fractals are introduced. Several points of evidence for the fractal nature of spots are provided. Specifically power laws are identified as signature of fractal properties, such as spectral power of noisy arc parameters (ion current, arc voltage, etc) obtained by fast Fourier transform. It is shown that fractal properties can be observed down to the cutoff by measurement resolution or occurrence of elementary steps in physical processes. Random walk models of cathode spot motion are well established: they go asymptotically to Brownian motion for infinitesimal step width. The power spectrum of the arc voltage noise falls as 1/f 2 , where f is frequency, supporting a fractal spot model associated with Brownian motion

Leaf and Canopy Level Detection of Fusarium Virguliforme (Sudden Death Syndrome in Soybean

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Ittai Herrmann

2018-03-01

Full Text Available Pre-visual detection of crop disease is critical for food security. Field-based spectroscopic remote sensing offers a method to enable timely detection, but still requires appropriate instrumentation and testing. Soybean plants were spectrally measured throughout a growing season to assess the capacity of leaf and canopy level spectral measurements to detect non-visual foliage symptoms induced by Fusarium virguliforme (Fv, which causes sudden death syndrome. Canopy reflectance measurements were made using the Piccolo Doppio dual field-of-view, two-spectrometer (400 to 1630 nm system on a tractor. Leaf level measurements were obtained, in different plots, using a handheld spectrometer (400 to 2500 nm. Partial least squares discriminant analysis (PLSDA was applied to the spectroscopic data to discriminate between Fv-inoculated and control plants. Canopy and leaf spectral data allowed identification of Fv infection, prior to visual symptoms, with classification accuracy of 88% and 91% for calibration, 79% and 87% for cross-validation, and 82% and 92% for validation, respectively. Differences in wavelengths important to prediction by canopy vs. leaf data confirm that there are different bases for accurate predictions among methods. Partial least square regression (PLSR was used on a late-stage canopy level data to predict soybean seed yield, with calibration, cross-validation and validation R2 values 0.71, 0.59 and 0.62 (p < 0.01, respectively, and validation root mean square error of 0.31 t·ha−1. Spectral data from the tractor mounted system are thus sensitive to the expression of Fv root infection at canopy scale prior to canopy symptoms, suggesting such systems may be effective for precision agricultural research and management.

Estimating leaf functional traits by inversion of PROSPECT: Assessing leaf dry matter content and specific leaf area in mixed mountainous forest

Science.gov (United States)

Ali, Abebe Mohammed; Darvishzadeh, Roshanak; Skidmore, Andrew K.; Duren, Iris van; Heiden, Uta; Heurich, Marco

2016-03-01

Assessments of ecosystem functioning rely heavily on quantification of vegetation properties. The search is on for methods that produce reliable and accurate baseline information on plant functional traits. In this study, the inversion of the PROSPECT radiative transfer model was used to estimate two functional leaf traits: leaf dry matter content (LDMC) and specific leaf area (SLA). Inversion of PROSPECT usually aims at quantifying its direct input parameters. This is the first time the technique has been used to indirectly model LDMC and SLA. Biophysical parameters of 137 leaf samples were measured in July 2013 in the Bavarian Forest National Park, Germany. Spectra of the leaf samples were measured using an ASD FieldSpec3 equipped with an integrating sphere. PROSPECT was inverted using a look-up table (LUT) approach. The LUTs were generated with and without using prior information. The effect of incorporating prior information on the retrieval accuracy was studied before and after stratifying the samples into broadleaf and conifer categories. The estimated values were evaluated using R2 and normalized root mean square error (nRMSE). Among the retrieved variables the lowest nRMSE (0.0899) was observed for LDMC. For both traits higher R2 values (0.83 for LDMC and 0.89 for SLA) were discovered in the pooled samples. The use of prior information improved accuracy of the retrieved traits. The strong correlation between the estimated traits and the NIR/SWIR region of the electromagnetic spectrum suggests that these leaf traits could be assessed at canopy level by using remotely sensed data.

Spectral reflectance relationships to leaf water stress

Science.gov (United States)

Ripple, William J.

1986-01-01

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

Comparison of leaf-on and leaf-off ALS data for mapping riparian tree species

Science.gov (United States)

Laslier, Marianne; Ba, Antoine; Hubert-Moy, Laurence; Dufour, Simon

2017-10-01

Forest species composition is a fundamental indicator of forest study and management. However, describing forest species composition at large scales and of highly diverse populations remains an issue for which remote sensing can provide significant contribution, in particular, Airborne Laser Scanning (ALS) data. Riparian corridors are good examples of highly valuable ecosystems, with high species richness and large surface areas that can be time consuming and expensive to monitor with in situ measurements. Remote sensing could be useful to study them, but few studies have focused on monitoring riparian tree species using ALS data. This study aimed to determine which metrics derived from ALS data are best suited to identify and map riparian tree species. We acquired very high density leaf-on and leaf-off ALS data along the Sélune River (France). In addition, we inventoried eight main riparian deciduous tree species along the study site. After manual segmentation of the inventoried trees, we extracted 68 morphological and structural metrics from both leaf-on and leaf-off ALS point clouds. Some of these metrics were then selected using Sequential Forward Selection (SFS) algorithm. Support Vector Machine (SVM) classification results showed good accuracy with 7 metrics (0.77). Both leaf-on and leafoff metrics were kept as important metrics for distinguishing tree species. Results demonstrate the ability of 3D information derived from high density ALS data to identify riparian tree species using external and internal structural metrics. They also highlight the complementarity of leaf-on and leaf-off Lidar data for distinguishing riparian tree species.

Specific leaf area estimation from leaf and canopy reflectance through optimization and validation of vegetation indices

NARCIS (Netherlands)

Ali, A.M.; Darvishzadeh, R.; Skidmore, A.K.; van Duren, I.C.

2017-01-01

Specific leaf area (SLA), which is defined as the leaf area per unit of dry leaf mass is an important component when assessing functional diversity and plays a key role in ecosystem modeling, linking plant carbon and water cycles as well as quantifying plant physiological processes. However, studies

Leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce

Science.gov (United States)

Rastogi, Gurdeep; Sbodio, Adrian; Tech, Jan J; Suslow, Trevor V; Coaker, Gitta L; Leveau, Johan H J

2012-01-01

The presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. However, information is scarce regarding their composition and how it changes along geographical and seasonal scales. We collected 106 samples of field-grown Romaine lettuce from commercial production regions in California and Arizona during the 2009–2010 crop cycle. Total bacterial populations averaged between 105 and 106 per gram of tissue, whereas counts of culturable bacteria were on average one (summer season) or two (winter season) orders of magnitude lower. Pyrosequencing of 16S rRNA gene amplicons from 88 samples revealed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundantly represented phyla. At the genus level, Pseudomonas, Bacillus, Massilia, Arthrobacter and Pantoea were the most consistently found across samples, suggesting that they form the bacterial ‘core' phyllosphere microbiota on lettuce. The foliar presence of Xanthomonas campestris pv. vitians, which is the causal agent of bacterial leaf spot of lettuce, correlated positively with the relative representation of bacteria from the genus Alkanindiges, but negatively with Bacillus, Erwinia and Pantoea. Summer samples showed an overrepresentation of Enterobacteriaceae sequences and culturable coliforms compared with winter samples. The distance between fields or the timing of a dust storm, but not Romaine cultivar, explained differences in bacterial community composition between several of the fields sampled. As one of the largest surveys of leaf surface microbiology, this study offers new insights into the extent and underlying causes of variability in bacterial community composition on plant leaves as a function of time, space and environment. PMID:22534606

Leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce.

Science.gov (United States)

Rastogi, Gurdeep; Sbodio, Adrian; Tech, Jan J; Suslow, Trevor V; Coaker, Gitta L; Leveau, Johan H J

2012-10-01

The presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. However, information is scarce regarding their composition and how it changes along geographical and seasonal scales. We collected 106 samples of field-grown Romaine lettuce from commercial production regions in California and Arizona during the 2009-2010 crop cycle. Total bacterial populations averaged between 10(5) and 10(6) per gram of tissue, whereas counts of culturable bacteria were on average one (summer season) or two (winter season) orders of magnitude lower. Pyrosequencing of 16S rRNA gene amplicons from 88 samples revealed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundantly represented phyla. At the genus level, Pseudomonas, Bacillus, Massilia, Arthrobacter and Pantoea were the most consistently found across samples, suggesting that they form the bacterial 'core' phyllosphere microbiota on lettuce. The foliar presence of Xanthomonas campestris pv. vitians, which is the causal agent of bacterial leaf spot of lettuce, correlated positively with the relative representation of bacteria from the genus Alkanindiges, but negatively with Bacillus, Erwinia and Pantoea. Summer samples showed an overrepresentation of Enterobacteriaceae sequences and culturable coliforms compared with winter samples. The distance between fields or the timing of a dust storm, but not Romaine cultivar, explained differences in bacterial community composition between several of the fields sampled. As one of the largest surveys of leaf surface microbiology, this study offers new insights into the extent and underlying causes of variability in bacterial community composition on plant leaves as a function of time, space and environment.

Laser Spot Detection Based on Reaction Diffusion

OpenAIRE

Alejandro Vázquez-Otero; Danila Khikhlukha; J. M. Solano-Altamirano; Raquel Dormido; Natividad Duro

2016-01-01

Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD) system as the main computational framework for robustly finding laser spot centers. The method presente...

7 CFR 28.415 - Low Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Low Middling Light Spotted Color. 28.415 Section 28... Spotted Color. Low Middling Light Spotted Color is color which in spot or color, or both, is between Low Middling Color and Low Middling Spotted Color. ...

Leaf hydraulic conductance declines in coordination with photosynthesis, transpiration and leaf water status as soybean leaves age regardless of soil moisture

Science.gov (United States)

Locke, Anna M.; Ort, Donald R.

2014-01-01

Photosynthesis requires sufficient water transport through leaves for stomata to remain open as water transpires from the leaf, allowing CO2 to diffuse into the leaf. The leaf water needs of soybean change over time because of large microenvironment changes over their lifespan, as leaves mature in full sun at the top of the canopy and then become progressively shaded by younger leaves developing above. Leaf hydraulic conductance (K leaf), a measure of the leaf’s water transport capacity, can often be linked to changes in microenvironment and transpiration demand. In this study, we tested the hypothesis that K leaf would decline in coordination with transpiration demand as soybean leaves matured and aged. Photosynthesis (A), stomatal conductance (g s) and leaf water potential (Ψleaf) were also measured at various leaf ages with both field- and chamber-grown soybeans to assess transpiration demand. K leaf was found to decrease as soybean leaves aged from maturity to shading to senescence, and this decrease was strongly correlated with midday A. Decreases in K leaf were further correlated with decreases in g s, although the relationship was not as strong as that with A. Separate experiments investigating the response of K leaf to drought demonstrated no acclimation of K leaf to drought conditions to protect against cavitation or loss of g s during drought and confirmed the effect of leaf age in K leaf observed in the field. These results suggest that the decline of leaf hydraulic conductance as leaves age keeps hydraulic supply in balance with demand without K leaf becoming limiting to transpiration water flux. PMID:25281701

Common garden comparison of the leaf-out phenology of woody species from different native climates, combined with herbarium records, forecasts long-term change.

Science.gov (United States)

Zohner, Constantin M; Renner, Susanne S

2014-08-01

A well-timed phenology is essential for plant growth and reproduction, but species-specific phenological strategies are still poorly understood. Here, we use a common garden approach to compare biannual leaf-out data for 495 woody species growing outdoors in Munich, 90% of them not native to that climate regime. For three species, data were augmented by herbarium dates for 140-year-long time series. We further meta-analysed 107 temperate-zone woody species in which leaf-out cues have been studied, half of them also monitored here. Southern climate-adapted species flushed significantly later than natives, and photoperiod- and chilling- sensitive species all flushed late. The herbarium method revealed the extent of species-specific climate tracking. Our results forecast that: (1) a northward expansion of southern species due to climate warming will increase the number of late flushers in the north, counteracting documented and expected flushing time advances; and (2) photoperiod- and chilling-sensitive woody species cannot rapidly track climate warming. © 2014 John Wiley & Sons Ltd/CNRS.

PyTranSpot: A tool for multiband light curve modeling of planetary transits and stellar spots

Science.gov (United States)

Juvan, Ines G.; Lendl, M.; Cubillos, P. E.; Fossati, L.; Tregloan-Reed, J.; Lammer, H.; Guenther, E. W.; Hanslmeier, A.

2018-02-01

Several studies have shown that stellar activity features, such as occulted and non-occulted starspots, can affect the measurement of transit parameters biasing studies of transit timing variations and transmission spectra. We present PyTranSpot, which we designed to model multiband transit light curves showing starspot anomalies, inferring both transit and spot parameters. The code follows a pixellation approach to model the star with its corresponding limb darkening, spots, and transiting planet on a two dimensional Cartesian coordinate grid. We combine PyTranSpot with a Markov chain Monte Carlo framework to study and derive exoplanet transmission spectra, which provides statistically robust values for the physical properties and uncertainties of a transiting star-planet system. We validate PyTranSpot's performance by analyzing eleven synthetic light curves of four different star-planet systems and 20 transit light curves of the well-studied WASP-41b system. We also investigate the impact of starspots on transit parameters and derive wavelength dependent transit depth values for WASP-41b covering a range of 6200-9200 Å, indicating a flat transmission spectrum.

Growth form and seasonal variation in leaf gas exchange of Colophospermum mopane savanna trees in northwest Botswana.

Science.gov (United States)

Veenendaal, Elmar M; Mantlana, Khanyisa B; Pammenter, Norman W; Weber, Piet; Huntsman-Mapila, Phillipa; Lloyd, Jon

2008-03-01

We investigated differences in physiological and morphological traits between the tall and short forms of mopane (Colophospermum mopane (Kirk ex Benth.) Kirk ex J. Léonard) trees growing near Maun, Botswana on a Kalahari sandveld overlying an impermeable calcrete duricrust. We sought to determine if differences between the two physiognomic types are attributable to the way they exploit available soil water. The tall form, which was located on deeper soil than the short form (5.5 versus 1.6 m), had a lower leaf:fine root biomass ratio (1:20 versus 1:6), but a similar leaf area index (0.9-1.0). Leaf nitrogen concentrations varied between 18 and 27 mg g(-1) and were about 20% higher in the tall form than in the short form. Maximum net assimilation rates (A sat) occurred during the rainy seasons (March-April 2000 and January-February 2001) and were similar in the tall and short forms (15-22 micromol m(-2) s(-1)) before declining to less than 10 micromol m(-2) s(-1) at the end of the rainy season in late April. As the dry season progressed, A sat, soil water content, predawn leaf water potential (Psi pd) and leaf nitrogen concentration declined rapidly. Before leaf abscission, Psi pd was more negative in the short form (-3.4 MPa) than in the tall form (-2.7 MPa) despite the greater availability of soil water beneath the short form trees. This difference appeared attributable to differences in root depth and density between the physiognomic types. Stomatal regulation of water use and carbon assimilation differed between years, with the tall form having a consistently more conservative water-use strategy as the dry season progressed than the short form.

Rocky Mountain spotted fever in Argentina.

Science.gov (United States)

Paddock, Christopher D; Fernandez, Susana; Echenique, Gustavo A; Sumner, John W; Reeves, Will K; Zaki, Sherif R; Remondegui, Carlos E

2008-04-01

We describe the first molecular confirmation of Rickettsia rickettsii, the cause of Rocky Mountain spotted fever (RMSF), from a tick vector, Amblyomma cajennense, and from a cluster of fatal spotted fever cases in Argentina. Questing A. cajennense ticks were collected at or near sites of presumed or confirmed cases of spotted fever rickettsiosis in Jujuy Province and evaluated by polymerase chain reaction assays for spotted fever group rickettsiae. DNA of R. rickettsii was amplified from a pool of A. cajennense ticks and from tissues of one of four patients who died during 2003-2004 after illnesses characterized by high fever, severe headache, myalgias, and petechial rash. The diagnosis of spotted fever rickettsiosis was confirmed in the other patients by indirect immunofluorescence antibody and immunohistochemical staining techniques. These findings show the existence of RMSF in Argentina and emphasize the need for clinicians throughout the Americas to consider RMSF in patients with febrile rash illnesses.

Crack imaging by pulsed laser spot thermography

International Nuclear Information System (INIS)

Li, T; Almond, D P; Rees, D A S; Weekes, B

2010-01-01

A surface crack close to a spot heated by a laser beam impedes lateral heat flow and produces alterations to the shape of the thermal image of the spot that can be monitored by thermography. A full 3D simulation has been developed to simulate heat flow from a laser heated spot in the proximity of a crack. The modelling provided an understanding of the ways that different parameters affect the thermal images of laser heated spots. It also assisted in the development of an efficient image processing strategy for extracting the scanned cracks. Experimental results show that scanning pulsed laser spot thermography has considerable potential as a remote, non-contact crack imaging technique.

Spot Welding of Honeycomb Structures

Science.gov (United States)

Cohal, V.

2017-08-01

Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

7 CFR 28.412 - Strict Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Light Spotted Color. 28.412 Section 28... Light Spotted Color. Strict Middling Light Spotted Color is color which in spot or color, or both, is between Strict Middling Color and Strict Middling Spotted Color. ...

7 CFR 28.411 - Good Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Good Middling Light Spotted Color. 28.411 Section 28... Light Spotted Color. Good Middling Light Spotted Color is color which in spot or color, or both, is between Good Middling Color and Good Middling Spotted Color. ...

DISTRIBUTION AND INCIDENCE LEAF DISEASES OF BANANA IN SEVERAL BANANA PRODUCTION CENTERS IN NORTH SUMATRA, WEST SUMATRA BENGKULU AND WEST JAVA

Directory of Open Access Journals (Sweden)

Sahlan

2011-06-01

Full Text Available The research was aimed to determine the type, the distribution and the incidence of banana leaf diseases in several production centers in West Sumatra, Bengkulu, North Sumatra and West Java. Direct observations on banana orchards were conducted in some districts in Simalungun, Deli Serdang and Medan (North Sumatra, Tanah Datar, Limapuluh Kota, Agam, Pariaman and Pasaman (West Sumatra, Rejang Lebong and Kepahyang (Bengkulu, Sukabumi, Purwakarta and Subang (West Java from November to December 2006. Two banana orchards were randomly selected in each district. Plant population at the selected orchard was at least 100 plants. From each sampled orchard, if banana population consisted of similar or only one variety, 10 plants were randomly chosen according to wind direction. Meanwhile, when the banana varieties were varied, five plants were randomly selected. The result showed that Black Sigatoka and Eumusae leaf spot were found in West Sumatra, Bengkulu and North Sumatra at severity level of between 15 % to 62.31%, whilst speckle disease was mainly found in North Sumatra and in parts of West Sumatra at severity level of between 72,72% to 100% and 15 to 30%, respectively. Banana varieties that were primarily attacked by leaf diseases were Cavendish, Telor, Barangan and Emas.

Seagrass leaf element content

NARCIS (Netherlands)

Vonk, J.A.; Smulders, Fee O.H.; Christianen, Marjolijn J.A.; Govers, Laura L.

2017-01-01

Knowledge on the role of seagrass leaf elements and in particular micronutrients and their ranges is limited. We present a global database, consisting of 1126 unique leaf values for ten elements, obtained from literature and unpublished data, spanning 25 different seagrass species from 28 countries.

Estimating leaf area and leaf biomass of open-grown deciduous urban trees

Science.gov (United States)

David J. Nowak

1996-01-01

Logarithmic regression equations were developed to predict leaf area and leaf biomass for open-grown deciduous urban trees based on stem diameter and crown parameters. Equations based on crown parameters produced more reliable estimates. The equations can be used to help quantify forest structure and functions, particularly in urbanizing and urban/suburban areas.

Prophylactic effect of paw-paw leaf and bitter leaf extracts on the ...

African Journals Online (AJOL)

STORAGESEVER

2008-08-18

Aug 18, 2008 ... (ANOVA) and significant means separated using FLSD = LSD procedure as outlined in Obi (2002). RESULTS AND DISCUSSION. In pre-soaking, paw-paw leaf (PL) extract had no significant effect (P > 0.05) on the disease incidence at. 50% anthesis. Bitter leaf (BL) extract had a high signifi- cant effect (P ...

Effect of ambient humidity on the rate at which blood spots dry and the size of the spot produced.

Science.gov (United States)

Denniff, Philip; Woodford, Lynsey; Spooner, Neil

2013-08-01

For shipping and storage, dried blood spot (DBS) samples must be sufficiently dry to protect the integrity of the sample. When the blood is spotted the humidity has the potential to affect the size of the spot created and the speed at which it dries. The area of DBS produced on three types of substrates were not affected by the humidity under which they were generated. DBS samples reached a steady moisture content 150 min after spotting and 90 min for humidities less than 60% relative humidity. All packaging materials examined provided some degree of protection from external extreme conditions. However, none of the packaging examined provided a total moisture barrier to extreme environmental conditions. Humidity was shown not to affect the spot area and DBS samples were ready for shipping and storage 2 h after spotting. The packing solutions examined all provided good protection from external high humidity conditions.

Timing and duration of autumn leaf development in Sweden, a 4-year citizen science study

Science.gov (United States)

Bolmgren, Kjell; Langvall, Ola

2017-04-01

Phenology monitoring has traditionally focused on the start of phenological phases and the start of the growing season, especially when it comes to species-specific observations on the ground. The patterns of and the mechanisms behind the end of particular phases and the growing season itself are less studied and poorly understood. With a changing climate, the need to understand and predict effects on the length as well as on the end of phenological phases increase in importance, e.g. in relation to estimations of carbon budgets and validation of remote sensing data. Furthermore, different species may be affected in different ways by changing conditions. In this 4-year-study, tens of thousands of pupils in ages from 6 to 19 years old were involved in observing autumn leaf development of common deciduous tree species. Their observations were made near schools all over Sweden (55-68°N). Observations were made weekly between late August and early November and followed an image-based observation protocol, classifying autumn leaf development into five levels, from a summer-green (level 0) to a 100% autumn-colored (level 4) canopy. As expected, there was a general (negative) correlation between latitude and the start of leaf senescence (level 2; 1/3 autumn-colored canopy), but the correlation differed largely among years and between species. There was a week correlation between latitude and duration of the leaf senescence period, defined as the period between 1/3 (level 2) and 100% (level 4) of autumn-colored canopy. A delayed onset of the leaf senescence affected the duration of the leaf senescence period more strongly; One (1) day later start was correlated with a 5-day shorter period. Different species had different length of their senescence period, with oak (mainly Quercus robur) and birches (Betula pendula and B. pubescence) having on average a 50% longer period than trembling aspen (Populus tremula) and Norway maple (Acer platanoides).

Unblinding the dark matter blind spots

International Nuclear Information System (INIS)

Han, Tao; Kling, Felix

2017-01-01

The dark matter (DM) blind spots in the Minimal Supersymmetric Standard Model (MSSM) refer to the parameter regions where the couplings of the DM particles to the Z-boson or the Higgs boson are almost zero, leading to vanishingly small signals for the DM direct detections. In this paper, we carry out comprehensive analyses for the DM searches under the blind-spot scenarios in MSSM. Guided by the requirement of acceptable DM relic abundance, we explore the complementary coverage for the theory parameters at the LHC, the projection for the future underground DM direct searches, and the indirect searches from the relic DM annihilation into photons and neutrinos. We find that (i) the spin-independent (SI) blind spots may be rescued by the spin-dependent (SD) direct detection in the future underground experiments, and possibly by the indirect DM detections from IceCube and SuperK neutrino experiments; (ii) the detection of gamma rays from Fermi-LAT may not reach the desirable sensitivity for searching for the DM blind-spot regions; (iii) the SUSY searches at the LHC will substantially extend the discovery region for the blind-spot parameters. As a result, the dark matter blind spots thus may be unblinded with the collective efforts in future DM searches.

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

Science.gov (United States)

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...

Using Leaf Samples to Establish a Library of Tropical Leaf Fingerprints

Science.gov (United States)

Ngo, P.; Nguyen, R.; Anderson, C.; Weiss, P.

2010-12-01

Variation in leaf chemistry is directly expressed in spectroscopic patterns of tropical canopies. The goal of the Spectranomics project is to explore this variation in the hopes of developing a method to measure tropical forest diversity remotely from airborne or space-bound spectroscopy in the future. We analyzed tomato leaves for various chemical compositions to better understand the Spectranomics approach to quantifying chemical data of tropical species. We also compared our data to standard data in each analysis. Our results allow us to give the tomato leaves a chemical signature in which we are able to use to compare to other leaf samples. Using this process, we are able to create a library of leaf signatures and document the variety of tree species in tropical forests around the world.

Leaf density explains variation in leaf mass per area in rice between cultivars and nitrogen treatments.

Science.gov (United States)

Xiong, Dongliang; Wang, Dan; Liu, Xi; Peng, Shaobing; Huang, Jianliang; Li, Yong

2016-05-01

Leaf mass per area (LMA) is an important leaf trait; however, correlations between LMA and leaf anatomical features and photosynthesis have not been fully investigated, especially in cereal crops. The objectives of this study were (a) to investigate the correlations between LMA and leaf anatomical traits; and (b) to clarify the response of LMA to nitrogen supply and its effect on photosynthetic nitrogen use efficiency (PNUE). In the present study, 11 rice varieties were pot grown under sufficient nitrogen (SN) conditions, and four selected rice cultivars were grown under low nitrogen (LN) conditions. Leaf anatomical traits, gas exchange and leaf N content were measured. There was large variation in LMA across selected rice varieties. Regression analysis showed that the variation in LMA was more closely related to leaf density (LD) than to leaf thickness (LT). LMA was positively related to the percentage of mesophyll tissue area (%mesophyll), negatively related to the percentage of epidermis tissue area (%epidermis) and unrelated to the percentage of vascular tissue area (%vascular). The response of LMA to N supplementation was dependent on the variety and was also mainly determined by the response of LD to N. Compared with SN, photosynthesis was significantly decreased under LN, while PNUE was increased. The increase in PNUE was more critical in rice cultivars with a higher LMA under SN supply. Leaf density is the major cause of the variation in LMA across rice varieties and N treatments, and an increase in LMA under high N conditions would aggravate the decrease in PNUE. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

ESA uncovers Geminga's `hot spot'

Science.gov (United States)

2004-07-01

whether Geminga’s tails are formed by electrons or by their twin particles with an opposite electrical charge, called positrons. Nevertheless, they expected that, if for instance electrons are kicked into space, then the positrons should be funnelled down towards the neutron star itself, like in an ‘own goal’. Where these particles strike the surface of the star, they ought to create a hot spot, a region considerably hotter than the surroundings. An international team of astronomers, lead by Patrizia Caraveo, IASF-CNR, Italy, has now reported the detection of such a hot spot on Geminga using ESA’s XMM-Newton observatory. With a temperature of about two million degrees, this hot spot is considerably hotter than the one half million degrees of the surrounding surface. According to this new work, Geminga’s hot spot is just 60 metres in radius. "This hot spot is the size of a football field," said Caraveo, "and is the smallest object ever detected outside of our Solar System." Details of this size can presently be measured only on the Moon and Mars and, even then, only from a spacecraft in orbit around them. The presence of a hot spot was suspected in the late 1990s but only now can we see it ‘live’, emitting X-rays as Geminga rotates, thanks to the superior sensitivity of ESA’s X-ray observatory, XMM-Newton. The team used the European Photon Imaging Cameras (EPIC) to conduct a study of Geminga, lasting about 28 consecutive hours and recording the arrival time and energy of every X-ray photon that Geminga emitted within XMM-Newton’s grasp. "In total, this amounted to 76 850 X-ray counts - twice as many as have been collected by all previous observations of Geminga, since the time of the Roman Empire," said Caraveo. Knowing the rotation rate of Geminga and the time of each photon’s arrival meant that astronomers could identify which photons were coming from each region of the neutron star as it rotates. When they compared photons coming from different

Evaluation of actual vs expected photodynamic therapy spot size.

Science.gov (United States)

Ranchod, Tushar M; Brucker, Alexander J; Liu, Chengcheng; Cukras, Catherine A; Hopkins, Tim B; Ying, Gui-Shuang

2009-05-01

To determine the accuracy of the photodynamic therapy (PDT) laser spot size on the retina as generated by 2 Food and Drug Administration (FDA)-approved lasers. Prospective observational case series. Fundus photographs were taken of 1 eye of each of 10 subjects with the WinStation 4000 fundus photography system (OIS; Ophthalmic Imaging Systems, Sacramento, California, USA); disc size was calculated using OIS software. Slit-lamp photographs were taken of the PDT laser spot focused on the retina adjacent to the optic disc, using various spot sizes in combination with 3 different contact lenses and 2 different lasers. Spot size at the retina was determined by measuring the ratio of disc diameter to spot diameter in Adobe Photoshop (San Jose, California, USA) and applying this ratio to the OIS disc measurements. Spot size at the retina averaged 87% of expected spot size for the Coherent Opal laser (Coherent Inc, Santa Clara, California, USA) and 104% of expected spot size for the Zeiss Visulas laser (Carl Zeiss Meditec Inc, Dublin, California, USA)(P = .002). Multivariate analysis demonstrated that percentage of expected spot size decreased with larger spot diameter (P = .01 for Coherent laser; P = .02 for Zeiss laser). PDT spot size at the retina appears to be consistently smaller than expected for the Coherent laser while the spot size was consistently within 10% of expected size for the Zeiss laser. The deviation from expected size increased with larger spot size using the Coherent laser.

Laser Spot Detection Based on Reaction Diffusion.

Science.gov (United States)

Vázquez-Otero, Alejandro; Khikhlukha, Danila; Solano-Altamirano, J M; Dormido, Raquel; Duro, Natividad

2016-03-01

Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD) system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations.

Secretome weaponries of Cochliobolus lunatus interacting with potato leaf at different temperature regimes reveal a CL[xxxx]LHM - motif.

Science.gov (United States)

Louis, Bengyella; Waikhom, Sayanika Devi; Roy, Pranab; Bhardwaj, Pardeep Kumar; Singh, Mohendro Wakambam; Goyari, Sailendra; Sharma, Chandradev K; Talukdar, Narayan Chandra

2014-03-20

Plant and animal pathogenic fungus Cochliobolus lunatus cause great economic damages worldwide every year. C. lunatus displays an increased temperature dependent-virulence to a wide range of hosts. Nonetheless, this phenomenon is poorly understood due to lack of insights on the coordinated secretome weaponries produced by C. lunatus under heat-stress conditions on putative hosts. To understand the mechanism better, we dissected the secretome of C. lunatus interacting with potato (Solanum tuberosum L.) leaf at different temperature regimes. C. lunatus produced melanized colonizing hyphae in and on potato leaf, finely modulated the ambient pH as a function of temperature and secreted diverse set of proteins. Using two dimensional gel electrophoresis (2-D) and mass spectrometry (MS) technology, we observed discrete secretomes at 20°C, 28°C and 38°C. A total of 21 differentially expressed peptide spots and 10 unique peptide spots (that did not align on the gels) matched with 28 unique protein models predicted from C. lunatus m118 v.2 genome peptides. Furthermore, C. lunatus secreted peptides via classical and non-classical pathways related to virulence, proteolysis, nucleic acid metabolism, carbohydrate metabolism, heat stress, signal trafficking and some with unidentified catalytic domains. We have identified a set of 5 soluble candidate effectors of unknown function from C. lunatus secretome weaponries against potato crop at different temperature regimes. Our findings demonstrate that C. lunatus has a repertoire of signature secretome which mediates thermo-pathogenicity and share a leucine rich "CL[xxxx]LHM"-motif. Considering the rapidly evolving temperature dependent-virulence and host diversity of C. lunatus, this data will be useful for designing new protection strategies.

7 CFR 30.2 - Leaf tobacco.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf tobacco. 30.2 Section 30.2 Agriculture... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.2 Leaf...

7 CFR 29.3035 - Leaf structure.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements...

7 CFR 29.3526 - Leaf scrap.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3526 Section 29.3526 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling...

7 CFR 29.3034 - Leaf scrap.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and...

7 CFR 29.6022 - Leaf scrap.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.6022 Section 29.6022 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results...

Infrared remote sensing for canopy temperature in paddy field and relationship between leaf temperature and leaf color

International Nuclear Information System (INIS)

Wakiyama, Y.

2002-01-01

Infrared remote sensing is used for crop monitoring, for example evaluation of water stress, detection of infected crops and estimation of transpiration and photosynthetic rates. This study was conducted to show another application of remote sensing information. The relationship between rice leaf temperature and chlorophyll content in the leaf blade was investigated by using thermography during the ripening period. The canopy of a rice community fertilized by top dressing was cooler than that not fertilized in a 1999 field experiment. In an experiment using thermocouples to measure leaf temperature, a rice leaf with high chlorophyll content was also cooler than that with a low chlorophyll content. Transpiration resistance and transpiration rate were measured with a porometer. Transpiration rate was higher with increasing chlorophyll content in the leaf blade. Stomatal aperture is related to chlorophyll content in the leaf blade. High degree of stomatal aperture is caused by high chlorophyll content in the leaf blade. As degree of stomatal aperture increases, transpiration rate increases. Therefore the rice leaf got cooler with increasing chlorophyll content in leaf blade. Paddy rice communities with different chlorophyll contents were provided with fertilization of different nitrogen levels on basal and top dressing in a 2000 field experiment. Canopy temperature of the rice community with high chlorophyll content was 0.85°C cooler than that of the rice community with low chlorophyll content. Results of this study revealed that infrared remote sensing could detect difference in chlorophyll contents in rice communities and could be used in fertilizer management in paddy fields. (author)

An analytical approach for optimizing the leaf design of a multi-leaf collimator in a linear accelerator

International Nuclear Information System (INIS)

Topolnjak, R; Heide, U A van der

2008-01-01

In this study, we present an analytical approach for optimizing the leaf design of a multi-leaf collimator (MLC) in a linear accelerator. Because leaf designs vary between vendors, our goal is to characterize and quantify the effects of different compromises which have to be made between performance parameters. Subsequently, an optimal leaf design for an earlier proposed six-bank MLC which combines a high-resolution field-shaping ability with a large field size is determined. To this end a model of the linac is created that includes the following parameters: the source size, the maximum field size, the distance between source and isocenter, and the leaf's design parameters. First, the optimal radius of the leaf tip was found. This optimum was defined by the requirement that the fluence intensity should fall from 80% of the maximum value to 20% in a minimal distance, defining the width of the fluence penumbra. A second requirement was that this penumbra width should be constant when a leaf moves from one side of the field to the other. The geometric, transmission and total penumbra width (80-20%) were calculated depending on the design parameters. The analytical model is in agreement with Elekta, Varian and Siemens collimator designs. For leaves thinner than 4 cm, the transmission penumbra becomes dominant, and for leaves close to the source the geometric penumbra plays a role. Finally, by choosing the leaf thickness of 3.5 cm, 4 cm and 5 cm from the lowest to the highest bank, respectively, an optimal leaf design for a six-bank MLC is achieved

Insights from ecological niche modeling on the taxonomic distinction and niche differentiation between the black-spotted and red-spotted tokay geckoes (Gekko gecko)

OpenAIRE

Zhang, Yueyun; Chen, Chongtao; Li, Li; Zhao, Chengjian; Chen, Weicai; Huang, Yong

2014-01-01

The black-spotted tokay and the red-spotted tokay are morphologically distinct and have largely allopatric distributions. The black-spotted tokay is characterized by a small body size and dark skin with sundry spots, while the red-spotted tokay has a relatively large body size and red spots. Based on morphological, karyotypic, genetic, and distribution differences, recent studies suggested their species status; however, their classifications remain controversial, and additional data such as e...

Small laser spot versus standard laser spot photodynamic therapy for idiopathic choroidal neovascularization: a randomized controlled study.

Science.gov (United States)

Li, Xiao-xin; Tao, Yong

2012-12-01

Idiopathic choroidal neovascularization (ICNV) affects young patients and thus may have a significant impact on vision and life quality over a patient's lifespan. This study was designed to compare the visual outcome and retinal pigment epithelium (RPE) damage after photodynamic therapy (PDT) with small laser spot and PDT with standard laser spot for idiopathic choroidal neovascularization (ICNV). This was a randomized controlled study. Fifty-two patients with ICNV were enrolled and randomly divided into a study group (small laser spot PDT, n = 27) and a control group (standard laser spot PDT, n = 25). Best corrected visual acuity (BCVA), optic coherence tomography (OCT) and fluorescein angiography (FA) findings were the main measurements. The patients were followed up 1 week, 1, 3, 6, 9 months and 1 year after PDT. BCVA improvement was statistically significantly higher in the study group than the control group at 6-month ((25.53 ± 15.01) letters vs. (14.71 ± 11.66) letters, P = 0.025) and 9-month follow-ups ((27.53 ± 17.78) letters vs. (15.59 ± 12.21) letters, P = 0.039). At 3- and 6-month follow-ups, the quadrants of RPE damage between the two groups varied significantly (P laser spot PDT group than in the standard laser spot PDT group for ICNV.

Apparent Overinvestment in Leaf Venation Relaxes Leaf Morphological Constraints on Photosynthesis in Arid Habitats1[OPEN

Science.gov (United States)

de Boer, Hugo J.; Drake, Paul L.; Wendt, Erin; Price, Charles A.; Schulze, Ernst-Detlef; Turner, Neil C.; Nicolle, Dean

2016-01-01

Leaf veins supply the mesophyll with water that evaporates when stomata are open to allow CO2 uptake for photosynthesis. Theoretical analyses suggest that water is optimally distributed in the mesophyll when the lateral distance between veins (dx) is equal to the distance from these veins to the epidermis (dy), expressed as dx:dy ≈ 1. Although this theory is supported by observations of many derived angiosperms, we hypothesize that plants in arid environments may reduce dx:dy below unity owing to climate-specific functional adaptations of increased leaf thickness and increased vein density. To test our hypothesis, we assembled leaf hydraulic, morphological, and photosynthetic traits of 68 species from the Eucalyptus and Corymbia genera (termed eucalypts) along an aridity gradient in southwestern Australia. We inferred the potential gas-exchange advantage of reducing dx beyond dy using a model that links leaf morphology and hydraulics to photosynthesis. Our observations reveal that eucalypts in arid environments have thick amphistomatous leaves with high vein densities, resulting in dx:dy ratios that range from 1.6 to 0.15 along the aridity gradient. Our model suggests that, as leaves become thicker, the effect of reducing dx beyond dy is to offset the reduction in leaf gas exchange that would result from maintaining dx:dy at unity. This apparent overinvestment in leaf venation may be explained from the selective pressure of aridity, under which traits associated with long leaf life span, high hydraulic and thermal capacitances, and high potential rates of leaf water transport confer a competitive advantage. PMID:27784769

A comparative study of x-ray emission from laser spots in laser-heated hohlraums relative to spots on simple disk targets

International Nuclear Information System (INIS)

Ze, F.; Langer, S.H.; Kauffman, R.L.; Kilkenny, J.D.; Landen, O.; Ress, D.; Rosen, M.D.; Suter, L.J.; Wallace, R.J.; Wiedwald, J.D.

1997-01-01

In this paper we report the results of experiments that compare the x-ray emission from a laser spot in a radiation-filled hohlraum to that from a similar laser spot on a simple disk target. The studies were done using the Nova laser facility [J. D. Lindl, Phys. Plasmas 2, 3933 (1995)] in its 0.35 μm wavelength, 1 ns square pulse configuration. Focal spot intensities were 2 endash 3.5x10 15 W/cm 2 . X-ray images measured x-ray conversion in a hohlraum and from an isolated disk simultaneously. A laser spot inside a hohlraum emitted more x rays, after subtracting the background emission from the hohlraum walls, than a spot on a disk. Numerical models suggest the enhanced spot emission inside the hohlraum is due to an increase in lateral transport relative to the disk. Filamentation in the hohlraum will also increase the spot size. The models agree fairly well with the results on spot spreading but do not explain the overall increase in conversion efficiency. copyright 1997 American Institute of Physics

Evaluation of 19,460 Wheat Accessions Conserved in the Indian National Genebank to Identify New Sources of Resistance to Rust and Spot Blotch Diseases

Science.gov (United States)

Jacob, Sherry R.; Srinivasan, Kalyani; Radhamani, J.; Parimalan, R.; Sivaswamy, M.; Tyagi, Sandhya; Yadav, Mamata; Kumari, Jyotisna; Deepali; Sharma, Sandeep; Bhagat, Indoo; Meeta, Madhu; Bains, N. S.; Chowdhury, A. K.; Saha, B. C.; Bhattacharya, P. M.; Kumari, Jyoti; Singh, M. C.; Gangwar, O. P.; Prasad, P.; Bharadwaj, S. C.; Gogoi, Robin; Sharma, J. B.; GM, Sandeep Kumar; Saharan, M. S.; Bag, Manas; Roy, Anirban; Prasad, T. V.; Sharma, R. K.; Dutta, M.; Sharma, Indu; Bansal, K. C.

2016-01-01

A comprehensive germplasm evaluation study of wheat accessions conserved in the Indian National Genebank was conducted to identify sources of rust and spot blotch resistance. Genebank accessions comprising three species of wheat–Triticum aestivum, T. durum and T. dicoccum were screened sequentially at multiple disease hotspots, during the 2011–14 crop seasons, carrying only resistant accessions to the next step of evaluation. Wheat accessions which were found to be resistant in the field were then assayed for seedling resistance and profiled using molecular markers. In the primary evaluation, 19,460 accessions were screened at Wellington (Tamil Nadu), a hotspot for wheat rusts. We identified 4925 accessions to be resistant and these were further evaluated at Gurdaspur (Punjab), a hotspot for stripe rust and at Cooch Behar (West Bengal), a hotspot for spot blotch. The second round evaluation identified 498 accessions potentially resistant to multiple rusts and 868 accessions potentially resistant to spot blotch. Evaluation of rust resistant accessions for seedling resistance against seven virulent pathotypes of three rusts under artificial epiphytotic conditions identified 137 accessions potentially resistant to multiple rusts. Molecular analysis to identify different combinations of genetic loci imparting resistance to leaf rust, stem rust, stripe rust and spot blotch using linked molecular markers, identified 45 wheat accessions containing known resistance genes against all three rusts as well as a QTL for spot blotch resistance. The resistant germplasm accessions, particularly against stripe rust, identified in this study can be excellent potential candidates to be employed for breeding resistance into the background of high yielding wheat cultivars through conventional or molecular breeding approaches, and are expected to contribute toward food security at national and global levels. PMID:27942031

Evaluation of 19,460 Wheat Accessions Conserved in the Indian National Genebank to Identify New Sources of Resistance to Rust and Spot Blotch Diseases.

Directory of Open Access Journals (Sweden)

Sundeep Kumar

Full Text Available A comprehensive germplasm evaluation study of wheat accessions conserved in the Indian National Genebank was conducted to identify sources of rust and spot blotch resistance. Genebank accessions comprising three species of wheat-Triticum aestivum, T. durum and T. dicoccum were screened sequentially at multiple disease hotspots, during the 2011-14 crop seasons, carrying only resistant accessions to the next step of evaluation. Wheat accessions which were found to be resistant in the field were then assayed for seedling resistance and profiled using molecular markers. In the primary evaluation, 19,460 accessions were screened at Wellington (Tamil Nadu, a hotspot for wheat rusts. We identified 4925 accessions to be resistant and these were further evaluated at Gurdaspur (Punjab, a hotspot for stripe rust and at Cooch Behar (West Bengal, a hotspot for spot blotch. The second round evaluation identified 498 accessions potentially resistant to multiple rusts and 868 accessions potentially resistant to spot blotch. Evaluation of rust resistant accessions for seedling resistance against seven virulent pathotypes of three rusts under artificial epiphytotic conditions identified 137 accessions potentially resistant to multiple rusts. Molecular analysis to identify different combinations of genetic loci imparting resistance to leaf rust, stem rust, stripe rust and spot blotch using linked molecular markers, identified 45 wheat accessions containing known resistance genes against all three rusts as well as a QTL for spot blotch resistance. The resistant germplasm accessions, particularly against stripe rust, identified in this study can be excellent potential candidates to be employed for breeding resistance into the background of high yielding wheat cultivars through conventional or molecular breeding approaches, and are expected to contribute toward food security at national and global levels.

Evaluation of 19,460 Wheat Accessions Conserved in the Indian National Genebank to Identify New Sources of Resistance to Rust and Spot Blotch Diseases.

Science.gov (United States)

Kumar, Sundeep; Archak, Sunil; Tyagi, R K; Kumar, Jagdish; Vk, Vikas; Jacob, Sherry R; Srinivasan, Kalyani; Radhamani, J; Parimalan, R; Sivaswamy, M; Tyagi, Sandhya; Yadav, Mamata; Kumari, Jyotisna; Deepali; Sharma, Sandeep; Bhagat, Indoo; Meeta, Madhu; Bains, N S; Chowdhury, A K; Saha, B C; Bhattacharya, P M; Kumari, Jyoti; Singh, M C; Gangwar, O P; Prasad, P; Bharadwaj, S C; Gogoi, Robin; Sharma, J B; Gm, Sandeep Kumar; Saharan, M S; Bag, Manas; Roy, Anirban; Prasad, T V; Sharma, R K; Dutta, M; Sharma, Indu; Bansal, K C

2016-01-01

A comprehensive germplasm evaluation study of wheat accessions conserved in the Indian National Genebank was conducted to identify sources of rust and spot blotch resistance. Genebank accessions comprising three species of wheat-Triticum aestivum, T. durum and T. dicoccum were screened sequentially at multiple disease hotspots, during the 2011-14 crop seasons, carrying only resistant accessions to the next step of evaluation. Wheat accessions which were found to be resistant in the field were then assayed for seedling resistance and profiled using molecular markers. In the primary evaluation, 19,460 accessions were screened at Wellington (Tamil Nadu), a hotspot for wheat rusts. We identified 4925 accessions to be resistant and these were further evaluated at Gurdaspur (Punjab), a hotspot for stripe rust and at Cooch Behar (West Bengal), a hotspot for spot blotch. The second round evaluation identified 498 accessions potentially resistant to multiple rusts and 868 accessions potentially resistant to spot blotch. Evaluation of rust resistant accessions for seedling resistance against seven virulent pathotypes of three rusts under artificial epiphytotic conditions identified 137 accessions potentially resistant to multiple rusts. Molecular analysis to identify different combinations of genetic loci imparting resistance to leaf rust, stem rust, stripe rust and spot blotch using linked molecular markers, identified 45 wheat accessions containing known resistance genes against all three rusts as well as a QTL for spot blotch resistance. The resistant germplasm accessions, particularly against stripe rust, identified in this study can be excellent potential candidates to be employed for breeding resistance into the background of high yielding wheat cultivars through conventional or molecular breeding approaches, and are expected to contribute toward food security at national and global levels.

7 CFR 29.6023 - Leaf structure.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its...

7 CFR 29.1030 - Leaf structure.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See...

7 CFR 29.3527 - Leaf structure.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See...

Comparative proteomic analysis of Typha angustifolia leaf under chromium, cadmium and lead stress

Energy Technology Data Exchange (ETDEWEB)

Bah, Alieu Mohamed; Sun Hongyan; Chen Fei; Zhou Jing; Dai Huaxin; Zhang Guoping [Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, Hangzhou 310029 (China); Wu Feibo, E-mail: wufeibo@zju.edu.cn [Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, Hangzhou 310029 (China)

2010-12-15

The present study investigated Typha angustifolia leaf proteome in response to Cr, Cd and Pb stress. T. angustifolia of 90 (D90) and 130 d (D130) old plants were subjected to 1 mM Cr, Cd and Pb and samples were collected 30 d after treatment. 2-DE coupled with MS (mass spectrometry) was used to analyze and identify Cr, Cd and Pb-responsive proteins. More than 1600 protein spots were reproducibly detected on each gel, wherein 44, 46, 66 and 33, 26, 62 spots in D90 and D130 samples were differentially expressed by Cr, Cd, Pb over the control, respectively. Of these differentially expressed proteins, 3, 1, 8 overlapped in D90 and D130; while 5, 8, 5 with regulation factors above 3 in one of D90 or D130 samples. Total of 22 and 4 up- and down-regulated proteins were identified using MS and data bank analysis. Cr-induced expression of ATP synthase, RuBisCO small subunit and coproporphyrinogen III oxidase; Cd-induced RuBisCO large subunit; Pb up-regulated carbohydrate metabolic pathway enzymes of fructokinase, and improved RuBisCO activase and large subunit, Mg-protoporphyrin IX chelatase. Contrarily, elF4F was inhibited by Cr/Pb, chloroplast FtsZ-like protein and GF14omega impeded by Cd and Pb, respectively.

Comparative proteomic analysis of Typha angustifolia leaf under chromium, cadmium and lead stress

International Nuclear Information System (INIS)

Bah, Alieu Mohamed; Sun Hongyan; Chen Fei; Zhou Jing; Dai Huaxin; Zhang Guoping; Wu Feibo

2010-01-01

The present study investigated Typha angustifolia leaf proteome in response to Cr, Cd and Pb stress. T. angustifolia of 90 (D90) and 130 d (D130) old plants were subjected to 1 mM Cr, Cd and Pb and samples were collected 30 d after treatment. 2-DE coupled with MS (mass spectrometry) was used to analyze and identify Cr, Cd and Pb-responsive proteins. More than 1600 protein spots were reproducibly detected on each gel, wherein 44, 46, 66 and 33, 26, 62 spots in D90 and D130 samples were differentially expressed by Cr, Cd, Pb over the control, respectively. Of these differentially expressed proteins, 3, 1, 8 overlapped in D90 and D130; while 5, 8, 5 with regulation factors above 3 in one of D90 or D130 samples. Total of 22 and 4 up- and down-regulated proteins were identified using MS and data bank analysis. Cr-induced expression of ATP synthase, RuBisCO small subunit and coproporphyrinogen III oxidase; Cd-induced RuBisCO large subunit; Pb up-regulated carbohydrate metabolic pathway enzymes of fructokinase, and improved RuBisCO activase and large subunit, Mg-protoporphyrin IX chelatase. Contrarily, elF4F was inhibited by Cr/Pb, chloroplast FtsZ-like protein and GF14omega impeded by Cd and Pb, respectively.

Comparison of dwarf bamboos (Indocalamus sp.) leaf parameters to determine relationship between spatial density of plants and total leaf area per plant.

Science.gov (United States)

Shi, Pei-Jian; Xu, Qiang; Sandhu, Hardev S; Gielis, Johan; Ding, Yu-Long; Li, Hua-Rong; Dong, Xiao-Bo

2015-10-01

The relationship between spatial density and size of plants is an important topic in plant ecology. The self-thinning rule suggests a -3/2 power between average biomass and density or a -1/2 power between stand yield and density. However, the self-thinning rule based on total leaf area per plant and density of plants has been neglected presumably because of the lack of a method that can accurately estimate the total leaf area per plant. We aimed to find the relationship between spatial density of plants and total leaf area per plant. We also attempted to provide a novel model for accurately describing the leaf shape of bamboos. We proposed a simplified Gielis equation with only two parameters to describe the leaf shape of bamboos one model parameter represented the overall ratio of leaf width to leaf length. Using this method, we compared some leaf parameters (leaf shape, number of leaves per plant, ratio of total leaf weight to aboveground weight per plant, and total leaf area per plant) of four bamboo species of genus Indocalamus Nakai (I. pedalis (Keng) P.C. Keng, I. pumilus Q.H. Dai and C.F. Keng, I. barbatus McClure, and I. victorialis P.C. Keng). We also explored the possible correlation between spatial density and total leaf area per plant using log-linear regression. We found that the simplified Gielis equation fit the leaf shape of four bamboo species very well. Although all these four species belonged to the same genus, there were still significant differences in leaf shape. Significant differences also existed in leaf area per plant, ratio of leaf weight to aboveground weight per plant, and leaf length. In addition, we found that the total leaf area per plant decreased with increased spatial density. Therefore, we directly demonstrated the self-thinning rule to improve light interception.

PENGARUH KURS SPOT DAN KURS FORWARD DALAM MEMPREDIKSI FUTURE SPOT PADA PASAR VALAS KAWASAN ASIA TENGGARA

Directory of Open Access Journals (Sweden)

I Gusti Ayu Kade Diana Yanthi

2013-10-01

Full Text Available The importance of the activity in foreign exchange occur as the result of the development of international trading and increased international money and capital movement. The vast development of international economic  caused  economic relationship  among  countries  will  be  linked  to  each other  and  subsequently improve trading activities in their goods, money and capital flows. The variables used in this study are spot, forward  and future  spot. Based  on  the result  of Regression  Estimation  applied in  hypothesis on foreign currencies exchange which done simultaneously are proven able to predict future spot. The investor and international economic  actor could use spot  exchange rate and forward  exchange rate as a  short terms predictor for the next trimester in 2011.

Palynological evidence for vegetation patterns in the Transvaal (South Africa during the late Pleistocene and Holocene

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L. Scott

1983-11-01

Full Text Available Palynological evidence relating to the nature of Late Quaternary vegetation types and plant migrations in the Transvaal is briefly summarized. It is suggested that, after an early temperate, relatively moist phase and a subsequent relatively dry phase lasting until about 25 000 yr B.P., a vegetation-type with ericaceous elements developed. It resembled belts presently occurring above the treeline and was possibly widespread over the plains of the Transvaal during the last glacial maximum period. In the central parts of the province, warm semi-arid savanna subsequently expanded during the early Holocene and was followed by a more broad-leafed type of woodland in the late Holocene. This change probably resulted from slightly wetter and, at times, also slightly warmer and cooler conditions.

Laser Spot Detection Based on Reaction Diffusion

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Alejandro Vázquez-Otero

2016-03-01

Full Text Available Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations.

Rocky Mountain spotted fever, Colombia.

Science.gov (United States)

Hidalgo, Marylin; Orejuela, Leonora; Fuya, Patricia; Carrillo, Pilar; Hernandez, Jorge; Parra, Edgar; Keng, Colette; Small, Melissa; Olano, Juan P; Bouyer, Donald; Castaneda, Elizabeth; Walker, David; Valbuena, Gustavo

2007-07-01

We investigated 2 fatal cases of Rocky Mountain spotted fever that occurred in 2003 and 2004 near the same locality in Colombia where the disease was first reported in the 1930s. A retrospective serosurvey of febrile patients showed that > 21% of the serum samples had antibodies aaainst spotted fever group rickettsiae.

Age Spots

Science.gov (United States)

... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Age Spots Treatment Options Learn more about treatment ...

Look-up-table approach for leaf area index retrieval from remotely sensed data based on scale information

Science.gov (United States)

Zhu, Xiaohua; Li, Chuanrong; Tang, Lingli

2018-03-01

Leaf area index (LAI) is a key structural characteristic of vegetation and plays a significant role in global change research. Several methods and remotely sensed data have been evaluated for LAI estimation. This study aimed to evaluate the suitability of the look-up-table (LUT) approach for crop LAI retrieval from Satellite Pour l'Observation de la Terre (SPOT)-5 data and establish an LUT approach for LAI inversion based on scale information. The LAI inversion result was validated by in situ LAI measurements, indicating that the LUT generated based on the PROSAIL (PROSPECT+SAIL: properties spectra + scattering by arbitrarily inclined leaves) model was suitable for crop LAI estimation, with a root mean square error (RMSE) of ˜0.31m2 / m2 and determination coefficient (R2) of 0.65. The scale effect of crop LAI was analyzed based on Taylor expansion theory, indicating that when the SPOT data aggregated by 200 × 200 pixel, the relative error is significant with 13.7%. Finally, an LUT method integrated with scale information was proposed in this article, improving the inversion accuracy with RMSE of 0.20 m2 / m2 and R2 of 0.83.

Non-nodulated bacterial leaf symbiosis promotes the evolutionary success of its host plants in the coffee family (Rubiaceae).

Science.gov (United States)

Verstraete, Brecht; Janssens, Steven; Rønsted, Nina

2017-08-01

Every plant species on Earth interacts in some way or another with microorganisms and it is well known that certain forms of symbiosis between different organisms can drive evolution. Within some clades of Rubiaceae (coffee family), a specific plant-bacteria interaction exists in which non-pathological endophytes are present in the leaves of their hosts. It is hypothesized that the bacterial endophytes, either alone or by interacting with the host, provide chemical protection against herbivory or pathogens by producing toxic or otherwise advantageous secondary metabolites. If the bacteria indeed have a direct beneficial influence on their hosts, it is reasonable to assume that the endophytes may increase the fitness of their hosts and therefore it is probable that their presence also has an influence on the long-term evolution of the particular plant lineages. In this study, the possible origin in time of non-nodulated bacterial leaf symbiosis in the Vanguerieae tribe of Rubiaceae is elucidated and dissimilarities in evolutionary dynamics between species with endophytes versus species without are investigated. Bacterial leaf symbiosis is shown to have most probably originated in the Late Miocene, a period when the savannah habitat is believed to have expanded on the African continent and herbivore pressure increased. The presence of bacterial leaf endophytes appears to be restricted to Old World lineages so far. Plant lineages with leaf endophytes show a significantly higher speciation rate than plant lineages without endophytes, while there is only a small difference in extinction rate. The transition rate shows that evolving towards having endophytes is twice as fast as evolving towards not having endophytes, suggesting that leaf symbiosis must be beneficial for the host plants. We conclude that the presence of bacterial leaf endophytes may also be an important driver for speciation of host plants. Copyright © 2017 Elsevier Inc. All rights reserved.

Splitting of turbulent spot in transitional pipe flow

Science.gov (United States)

Wu, Xiaohua; Moin, Parviz; Adrian, Ronald J.

2017-11-01

Recent study (Wu et al., PNAS, 1509451112, 2015) demonstrated the feasibility and accuracy of direct computation of the Osborne Reynolds' pipe transition problem without the unphysical, axially periodic boundary condition. Here we use this approach to study the splitting of turbulent spot in transitional pipe flow, a feature first discovered by E.R. Lindgren (Arkiv Fysik 15, 1959). It has been widely believed that spot splitting is a mysterious stochastic process that has general implications on the lifetime and sustainability of wall turbulence. We address the following two questions: (1) What is the dynamics of turbulent spot splitting in pipe transition? Specifically, we look into any possible connection between the instantaneous strain rate field and the spot splitting. (2) How does the passive scalar field behave during the process of pipe spot splitting. In this study, the turbulent spot is introduced at the inlet plane through a sixty degree wide numerical wedge within which fully-developed turbulent profiles are assigned over a short time interval; and the simulation Reynolds numbers are 2400 for a 500 radii long pipe, and 2300 for a 1000 radii long pipe, respectively. Numerical dye is tagged on the imposed turbulent spot at the inlet. Splitting of the imposed turbulent spot is detected very easily. Preliminary analysis of the DNS results seems to suggest that turbulent spot slitting can be easily understood based on instantaneous strain rate field, and such spot splitting may not be relevant in external flows such as the flat-plate boundary layer.

Laser based spot weld characterization

Science.gov (United States)

Jonietz, Florian; Myrach, Philipp; Rethmeier, Michael; Suwala, Hubert; Ziegler, Mathias

2016-02-01

Spot welding is one of the most important joining technologies, especially in the automotive industry. Hitherto, the quality of spot welded joints is tested mainly by random destructive tests. A nondestructive testing technique offers the benefit of cost reduction of the testing procedure and optimization of the fabrication process, because every joint could be examined. This would lead to a reduced number of spot welded joints, as redundancies could be avoided. In the procedure described here, the spot welded joint between two zinc-coated steel sheets (HX340LAD+Z100MB or HC340LA+ZE 50/50) is heated optically on one side. Laser radiation and flash light are used as heat sources. The melted zone, the so called "weld nugget" provides the mechanical stability of the connection, but also constitutes a thermal bridge between the sheets. Due to the better thermal contact, the spot welded joint reveals a thermal behavior different from the surrounding material, where the heat transfer between the two sheets is much lower. The difference in the transient thermal behavior is measured with time resolved thermography. Hence, the size of the thermal contact between the two sheets is determined, which is directly correlated to the size of the weld nugget, indicating the quality of the spot weld. The method performs well in transmission with laser radiation and flash light. With laser radiation, it works even in reflection geometry, thus offering the possibility of testing with just one-sided accessibility. By using heating with collimated laser radiation, not only contact-free, but also remote testing is feasible. A further convenience compared to similar thermographic approaches is the applicability on bare steel sheets without any optical coating for emissivity correction. For this purpose, a proper way of emissivity correction was established.

Advanced spot quality analysis in two-colour microarray experiments

Directory of Open Access Journals (Sweden)

Vetter Guillaume

2008-09-01

Full Text Available Abstract Background Image analysis of microarrays and, in particular, spot quantification and spot quality control, is one of the most important steps in statistical analysis of microarray data. Recent methods of spot quality control are still in early age of development, often leading to underestimation of true positive microarray features and, consequently, to loss of important biological information. Therefore, improving and standardizing the statistical approaches of spot quality control are essential to facilitate the overall analysis of microarray data and subsequent extraction of biological information. Findings We evaluated the performance of two image analysis packages MAIA and GenePix (GP using two complementary experimental approaches with a focus on the statistical analysis of spot quality factors. First, we developed control microarrays with a priori known fluorescence ratios to verify the accuracy and precision of the ratio estimation of signal intensities. Next, we developed advanced semi-automatic protocols of spot quality evaluation in MAIA and GP and compared their performance with available facilities of spot quantitative filtering in GP. We evaluated these algorithms for standardised spot quality analysis in a whole-genome microarray experiment assessing well-characterised transcriptional modifications induced by the transcription regulator SNAI1. Using a set of RT-PCR or qRT-PCR validated microarray data, we found that the semi-automatic protocol of spot quality control we developed with MAIA allowed recovering approximately 13% more spots and 38% more differentially expressed genes (at FDR = 5% than GP with default spot filtering conditions. Conclusion Careful control of spot quality characteristics with advanced spot quality evaluation can significantly increase the amount of confident and accurate data resulting in more meaningful biological conclusions.

Detecting hot spots at hazardous-waste sites

International Nuclear Information System (INIS)

Zirschky, J.; Gilbert, R.O.

1984-01-01

Evaluating the need for remedial cleanup at a waste site involves both finding the average contaminant concentration and identifying highly contaminated areas, or hot spots. A nomographic procedure to determine the sample configuration needed to locate a hot spot is presented. The technique can be used to develop a waste-site sampling plant - to determine either the grid spacing required to detect a hot spot at a given level of confidence, or the probability of finding a hot spot of a certain size, given a particular grid spacing. The method and computer program (ELIPGRID) were developed for locating geologic deposits, but the basic procedure can also be used to detect hot spots at chemical- or nuclear-waste disposal sites. Nomographs based on the original program are presented for three sampling-grid configurations - square, rectangular and triangular

Modeling demographic performance of northern spotted owls relative to forest habitat in Oregon

Science.gov (United States)

Olson, Gail S.; Glenn, Elizabeth M.; Anthony, Robert G.; Forsman, Eric D.; Reid, Janice A.; Loschl, Peter J.; Ripple, William J.

2004-01-01

Northern spotted owls (Strix occidentalis caurina) are known to be associated with late-successional forests in the Pacific Northwest of the United States, but the effects of habitat on their demographic performance are relatively unknown. We developed statistical models relating owl survival and productivity to forest cover types within the Roseburg Study Area in the Oregon Coast Range of Oregon, USA. We further combined these demographic parameters using a Leslie-type matrix to obtain an estimate of habitat fitness potential for each owl territory (n = 94). We used mark–recapture methods to develop models for survival and linear mixed models for productivity. We measured forest composition and landscape patterns at 3 landscape scales centered on nest and activity sites within owl territories using an aerial photo-based map and a Geographic Information System (GIS). We also considered additional covariates such as age, sex, and presence of barred owls (Strix varia), and seasonal climate variables (temperature and precipitation) in our models. We used Akaike's Information Criterion (AIC) to rank and compare models. Survival had a quadratic relationship with the amount of late- and mid-seral forests within 1,500 m of nesting centers. Survival also was influenced by the amount of precipitation during the nesting season. Only 16% of the variability in survival was accounted for by our best model, but 85% of this was due to the habitat variable. Reproductive rates fluctuated biennially and were positively related to the amount of edge between late- and mid-seral forests and other habitat classes. Reproductive rates also were influenced by parent age, amount of precipitation during nesting season, and presence of barred owls. Our best model accounted for 84% of the variability in productivity, but only 3% of that was due to the habitat variable. Estimates of habitat fitness potential (which may range from 0 to infinity) for the 94 territories ranged from 0.74 to 1

Judging a salmon by its spots: environmental variation is the primary determinant of spot patterns in Salmo salar.

Science.gov (United States)

Jørgensen, Katarina M; Solberg, Monica F; Besnier, Francois; Thorsen, Anders; Fjelldal, Per Gunnar; Skaala, Øystein; Malde, Ketil; Glover, Kevin A

2018-04-12

In fish, morphological colour changes occur from variations in pigment concentrations and in the morphology, density, and distribution of chromatophores in the skin. However, the underlying mechanisms remain unresolved in most species. Here, we describe the first investigation into the genetic and environmental basis of spot pattern development in one of the world's most studied fishes, the Atlantic salmon. We reared 920 salmon from 64 families of domesticated, F1-hybrid and wild origin in two contrasting environments (Hatchery; tanks for the freshwater stage and sea cages for the marine stage, and River; a natural river for the freshwater stage and tanks for the marine stage). Fish were measured, photographed and spot patterns evaluated. In the Hatchery experiment, significant but modest differences in spot density were observed among domesticated, F1-hybrid (1.4-fold spottier than domesticated) and wild salmon (1.7-fold spottier than domesticated). A heritability of 6% was calculated for spot density, and a significant QTL on linkage group SSA014 was detected. In the River experiment, significant but modest differences in spot density were also observed among domesticated, F1-hybrid (1.2-fold spottier than domesticated) and wild salmon (1.8-fold spottier than domesticated). Domesticated salmon were sevenfold spottier in the Hatchery vs. River experiment. While different wild populations were used for the two experiments, on average, these were 6.2-fold spottier in the Hatchery vs. River experiment. Fish in the Hatchery experiment displayed scattered to random spot patterns while fish in the River experiment displayed clustered spot patterns. These data demonstrate that while genetics plays an underlying role, environmental variation represents the primary determinant of spot pattern development in Atlantic salmon.

Impact of spot charge inaccuracies in IMPT treatments.

Science.gov (United States)

Kraan, Aafke C; Depauw, Nicolas; Clasie, Ben; Giunta, Marina; Madden, Tom; Kooy, Hanne M

2017-08-01

Spot charge is one parameter of pencil-beam scanning dose delivery system whose accuracy is typically high but whose required value has not been investigated. In this work we quantify the dose impact of spot charge inaccuracies on the dose distribution in patients. Knowing the effect of charge errors is relevant for conventional proton machines, as well as for new generation proton machines, where ensuring accurate charge may be challenging. Through perturbation of spot charge in treatment plans for seven patients and a phantom, we evaluated the dose impact of absolute (up to 5× 10 6 protons) and relative (up to 30%) charge errors. We investigated the dependence on beam width by studying scenarios with small, medium and large beam sizes. Treatment plan statistics included the Γ passing rate, dose-volume-histograms and dose differences. The allowable absolute charge error for small spot plans was about 2× 10 6 protons. Larger limits would be allowed if larger spots were used. For relative errors, the maximum allowable error size for small, medium and large spots was about 13%, 8% and 6% for small, medium and large spots, respectively. Dose distributions turned out to be surprisingly robust against random spot charge perturbation. Our study suggests that ensuring spot charge errors as small as 1-2% as is commonly aimed at in conventional proton therapy machines, is clinically not strictly needed. © 2017 American Association of Physicists in Medicine.

Ozone induced leaf loss and decreased leaf production of European Holly (Ilex aquifolium L.) over multiple seasons

International Nuclear Information System (INIS)

Ranford, Jonathan; Reiling, Kevin

2007-01-01

European Holly (Ilex aquifolium L.) was used to study the impact of one short (28 day) ozone fumigation episode on leaf production, leaf loss and stomatal conductance (g s ), in order to explore potential longer term effects over 3 growing seasons. Young I. aquifolium plants received an episode of either charcoal-filtered air or charcoal-filtered air with 70 nl l -1 O 3 added for 7 h d -1 over a 28 day period from June 15th 1996, then placed into ambient environment, Stoke-on-Trent, U.K. Data were collected per leaf cohort over the next three growing seasons. Ozone exposure significantly increased leaf loss and stomatal conductance and reduced leaf production over all subsequent seasons. Impact of the initial ozone stress was still detected in leaves that had no direct experimental ozone exposure. This study has shown the potential of ozone to introduce long-term phenological perturbations into ecosystems by influencing productivity over a number of seasons. - Ozone significantly alters Ilex aquifolium leaf production and loss over multiple seasons

Spot: A Programming Language for Verified Flight Software

Science.gov (United States)

Bocchino, Robert L., Jr.; Gamble, Edward; Gostelow, Kim P.; Some, Raphael R.

2014-01-01

The C programming language is widely used for programming space flight software and other safety-critical real time systems. C, however, is far from ideal for this purpose: as is well known, it is both low-level and unsafe. This paper describes Spot, a language derived from C for programming space flight systems. Spot aims to maintain compatibility with existing C code while improving the language and supporting verification with the SPIN model checker. The major features of Spot include actor-based concurrency, distributed state with message passing and transactional updates, and annotations for testing and verification. Spot also supports domain-specific annotations for managing spacecraft state, e.g., communicating telemetry information to the ground. We describe the motivation and design rationale for Spot, give an overview of the design, provide examples of Spot's capabilities, and discuss the current status of the implementation.

Hot spot formation on different tokamak wall materials

International Nuclear Information System (INIS)

Nedospasov, A.V.; Bezlyudny, I.V.

1998-01-01

The thermal contraction phenomenon and generation of 'hot spots' due to thermoemission were described. The paper consider non-linear stages of heat contraction on the graphite, beryllium, tungsten and vanadium wall. It is shown that on the beryllium surface hot spot can't appear due to strong cooling by sublimation. For other materials the conditions of hot spot appearance due to local superheating of the wall have been calculated and their parameters were found: critical surface temperature, size of spots and their temperature profiles, heat fluxes from plasma to the spots. It have been calculated fluxes of sublimating materials from spots to the plasma. It is noticed that nominal temperature of the grafite divertor plate, accepted in ITER's project to being equal 1500 C, is lower then critical temperature of the development heat contraction due to thermoemission. (orig.)

Photoperiod-H1 (Ppd-H1) Controls Leaf Size.

Science.gov (United States)

Digel, Benedikt; Tavakol, Elahe; Verderio, Gabriele; Tondelli, Alessandro; Xu, Xin; Cattivelli, Luigi; Rossini, Laura; von Korff, Maria

2016-09-01

Leaf size is a major determinant of plant photosynthetic activity and biomass; however, it is poorly understood how leaf size is genetically controlled in cereal crop plants like barley (Hordeum vulgare). We conducted a genome-wide association scan for flowering time, leaf width, and leaf length in a diverse panel of European winter cultivars grown in the field and genotyped with a single-nucleotide polymorphism array. The genome-wide association scan identified PHOTOPERIOD-H1 (Ppd-H1) as a candidate gene underlying the major quantitative trait loci for flowering time and leaf size in the barley population. Microscopic phenotyping of three independent introgression lines confirmed the effect of Ppd-H1 on leaf size. Differences in the duration of leaf growth and consequent variation in leaf cell number were responsible for the leaf size differences between the Ppd-H1 variants. The Ppd-H1-dependent induction of the BARLEY MADS BOX genes BM3 and BM8 in the leaf correlated with reductions in leaf size and leaf number. Our results indicate that leaf size is controlled by the Ppd-H1- and photoperiod-dependent progression of plant development. The coordination of leaf growth with flowering may be part of a reproductive strategy to optimize resource allocation to the developing inflorescences and seeds. © 2016 American Society of Plant Biologists. All rights reserved.

Exploring the possibility of using digital image processing technique to detect diseases of rice leaf

Directory of Open Access Journals (Sweden)

S. H Peyman

2016-04-01

Full Text Available Introduction: Rice is a very important staple food crop provides more than half of the world caloric supply. Rice diseases lead to significant annual crop losses, have negative impacts on quality of the final product and destroy plant variety. Rice Blast is one of the most widespread and most destructive fungal diseases in tropical and subtropical humid areas, which causes significant decrease in the amount of paddy yield and quality of milled rice. Brown spot disease is another important fungal disease in rice which infects the plant during the rice growing season from the nursery period up to farm growth stage and productivity phase. The later the disease is diagnosed the higher the amount of chemicals is needed for treatment. Due to high costs and harmful environmental impacts of chemical toxins, the accurate early detection and treatment of plant disease is seemed to be necessary. In general, observation with the naked eye is used for disease detection. However, the results are indeed depend on the intelligence of the person performing the operation. So usually the accurate determination of the severity and progression of the disease can’t be achieved. On the other side, the use of experts for continuous monitoring of large farms might be prohibitively expensive and time consuming. Thus, investigating the new approaches for rapid, automated, inexpensive and accurate plant disease diagnosis is very important. Machine vision and image processing is a new technique which can capture images from a scene of interest, analyze the images and accurately extract the desired information. Studies show that image processing techniques have been successfully used for plant disease detection. The aim of this study was to investigate the ability of image processing techniques for diagnosing the rice blast and rice brown spot. Materials and Methods: The samples of rice leaf infected by brown spot and rice blast diseases were collected from rice fields and

Volume higher; spot price ranges widen

International Nuclear Information System (INIS)

Anon.

1994-01-01

This article is the October 1994 uranium market summary. During this reporting period, volume on the spot concentrates market doubled. Twelve deals took place: three in the spot concentrates market, one in the medium and long-term market, four in the conversion market, and four in the enrichment market. The restricted price range widened due to higher prices at the top end of the range, while the unrestricted price range widened because of lower prices at the bottom end. Spot conversion prices were higher, and enrichment prices were unchanged

Space-time modeling of electricity spot prices

DEFF Research Database (Denmark)

Abate, Girum Dagnachew; Haldrup, Niels

In this paper we derive a space-time model for electricity spot prices. A general spatial Durbin model that incorporates the temporal as well as spatial lags of spot prices is presented. Joint modeling of space-time effects is necessarily important when prices and loads are determined in a network...... in the spot price dynamics. Estimation of the spatial Durbin model show that the spatial lag variable is as important as the temporal lag variable in describing the spot price dynamics. We use the partial derivatives impact approach to decompose the price impacts into direct and indirect effects and we show...... that price effects transmit to neighboring markets and decline with distance. In order to examine the evolution of the spatial correlation over time, a time varying parameters spot price spatial Durbin model is estimated using recursive estimation. It is found that the spatial correlation within the Nord...

The invasive spotted-wing Drosophila (Diptera, Drosophilidae has been found in the city of São Paulo (Brazil

Directory of Open Access Journals (Sweden)

Carlos Ribeiro Vilela

2014-12-01

Full Text Available The invasive spotted-wing Drosophila (Diptera, Drosophilidae has been found in the city of São Paulo (Brazil. Drosophila suzukii (Matsumura, 1931, the cherry fly or spotted-wing Drosophila, a pest species from the Oriental and southeastern Palaearctic regions belonging to the melanogaster group, invaded the Nearctic and western countries of the Palaearctic regions late last decade (2008 and, more recently (2013, the southern Brazilian states of Rio Grande do Sul and Santa Catarina. Early in 2014 it was reared from blueberries produced in São Joaquim, state of Santa Catarina, that were bought at a São Paulo city grocery store. Despite being a cold-adapted species, after having arrived to the southeastern state of São Paulo, this invasive fly will probably expand its territory to other Brazilian states and South American countries through trade of cultivated soft skin small fruits, such as blueberries and strawberries, as well as naturally through the use of small wild fruits as breeding sites.

Poisson's spot and Gouy phase

Science.gov (United States)

da Paz, I. G.; Soldati, Rodolfo; Cabral, L. A.; de Oliveira, J. G. G.; Sampaio, Marcos

2016-12-01

Recently there have been experimental results on Poisson spot matter-wave interferometry followed by theoretical models describing the relative importance of the wave and particle behaviors for the phenomenon. We propose an analytical theoretical model for Poisson's spot with matter waves based on the Babinet principle, in which we use the results for free propagation and single-slit diffraction. We take into account effects of loss of coherence and finite detection area using the propagator for a quantum particle interacting with an environment. We observe that the matter-wave Gouy phase plays a role in the existence of the central peak and thus corroborates the predominantly wavelike character of the Poisson's spot. Our model shows remarkable agreement with the experimental data for deuterium (D2) molecules.

Wind increases leaf water use efficiency.

Science.gov (United States)

Schymanski, Stanislaus J; Or, Dani

2016-07-01

A widespread perception is that, with increasing wind speed, transpiration from plant leaves increases. However, evidence suggests that increasing wind speed enhances carbon dioxide (CO2 ) uptake while reducing transpiration because of more efficient convective cooling (under high solar radiation loads). We provide theoretical and experimental evidence that leaf water use efficiency (WUE, carbon uptake per water transpired) commonly increases with increasing wind speed, thus improving plants' ability to conserve water during photosynthesis. Our leaf-scale analysis suggests that the observed global decrease in near-surface wind speeds could have reduced WUE at a magnitude similar to the increase in WUE attributed to global rise in atmospheric CO2 concentrations. However, there is indication that the effect of long-term trends in wind speed on leaf gas exchange may be compensated for by the concurrent reduction in mean leaf sizes. These unintuitive feedbacks between wind, leaf size and water use efficiency call for re-evaluation of the role of wind in plant water relations and potential re-interpretation of temporal and geographic trends in leaf sizes. © 2015 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

7 CFR 28.421 - Good Middling Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Good Middling Spotted Color. 28.421 Section 28.421 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Color. Good Middling Spotted Color is color which is better than Strict Middling Spotted Color. ...

Spatiotemporal chaos of self-replicating spots in reaction-diffusion systems.

Science.gov (United States)

Wang, Hongli; Ouyang, Qi

2007-11-23

The statistical properties of self-replicating spots in the reaction-diffusion Gray-Scott model are analyzed. In the chaotic regime of the system, the spots that dominate the spatiotemporal chaos grow and divide in two or decay into the background randomly and continuously. The rates at which the spots are created and decay are observed to be linearly dependent on the number of spots in the system. We derive a probabilistic description of the spot dynamics based on the statistical independence of spots and thus propose a characterization of the spatiotemporal chaos dominated by replicating spots.

Relating Stomatal Conductance to Leaf Functional Traits.

Science.gov (United States)

Kröber, Wenzel; Plath, Isa; Heklau, Heike; Bruelheide, Helge

2015-10-12

Leaf functional traits are important because they reflect physiological functions, such as transpiration and carbon assimilation. In particular, morphological leaf traits have the potential to summarize plants strategies in terms of water use efficiency, growth pattern and nutrient use. The leaf economics spectrum (LES) is a recognized framework in functional plant ecology and reflects a gradient of increasing specific leaf area (SLA), leaf nitrogen, phosphorus and cation content, and decreasing leaf dry matter content (LDMC) and carbon nitrogen ratio (CN). The LES describes different strategies ranging from that of short-lived leaves with high photosynthetic capacity per leaf mass to long-lived leaves with low mass-based carbon assimilation rates. However, traits that are not included in the LES might provide additional information on the species' physiology, such as those related to stomatal control. Protocols are presented for a wide range of leaf functional traits, including traits of the LES, but also traits that are independent of the LES. In particular, a new method is introduced that relates the plants' regulatory behavior in stomatal conductance to vapor pressure deficit. The resulting parameters of stomatal regulation can then be compared to the LES and other plant functional traits. The results show that functional leaf traits of the LES were also valid predictors for the parameters of stomatal regulation. For example, leaf carbon concentration was positively related to the vapor pressure deficit (vpd) at the point of inflection and the maximum of the conductance-vpd curve. However, traits that are not included in the LES added information in explaining parameters of stomatal control: the vpd at the point of inflection of the conductance-vpd curve was lower for species with higher stomatal density and higher stomatal index. Overall, stomata and vein traits were more powerful predictors for explaining stomatal regulation than traits used in the LES.

7 CFR 30.31 - Classification of leaf tobacco.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Classification of leaf tobacco. 30.31 Section 30.31... REGULATIONS TOBACCO STOCKS AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.31 Classification of leaf tobacco. For the purpose of this classification leaf tobacco shall...

High-resolution UV-visible spectroscopy of lunar red spots

Science.gov (United States)

Bruno, B. C.; Lucey, P. G.; Hawke, B. R.

1991-01-01

A spectral reflectance study of selected lunar 'red spots', highland areas characterized by an absorption in the ultraviolet relative to the visible was conducted. Some red spots were suggested to be the sites of ancient highland volcanism. High-resolution spectral data of eight red spots on the western portion of the moon over the wavelength region 0.39-0.82 micron were obtained. Much spectral variation among these red spots in the magnitude as well as the wavelength position of the ultraviolet absorption were found. Spectral structure at visible and near-infrared wavelength were also identified. These spectral differences indicate that red spots do not have a single mineralogical composition, which in turn suggests that red spots may have multiple origins. Additional imaging spectroscopic observations were taken of the Herigonius red spot, a morphologically complex region northeast of Mare Humorum. These data reveal significant spectral differences among the various morphological units within the Herigonius red spot. Although some of these are likely due to the effects of the maturation process, others appear to reflect differences in mineral abundances and composition.

Biophysical control of leaf temperature

Science.gov (United States)

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 (ΔT), the latter to the transpiration rate. We present field measurements of ΔT 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 (ω) 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 ΔT) 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

Tuning temperature and size of hot spots and hot-spot arrays.

Science.gov (United States)

Saïdi, Elika; Babinet, Nicolas; Lalouat, Loïc; Lesueur, Jérôme; Aigouy, Lionel; Volz, Sébastian; Labéguerie-Egéa, Jessica; Mortier, Michel

2011-01-17

By using scanning thermal microscopy, it is shown that nanoscale constrictions in metallic microwires deposited on an oxidized silicon substrate can be tuned in terms of temperature and confinement size. High-resolution temperature maps indeed show that submicrometer hot spots and hot-spot arrays are obtained when the SiO(2) layer thickness decreases below 100 nm. When the SiO(2) thickness becomes larger, heat is less confined in the vicinity of the constrictions and laterally spreads all along the microwire. These results are in good agreement with numerical simulations, which provide dependences between silica-layer thickness and nanodot shape and temperature. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The spot market and the spot price: applicability and limitations

International Nuclear Information System (INIS)

White, G. Jr.

1987-01-01

The subject of spot prices and their relationship to long-term contracting is addressed. The author is associated with Nuexco, which originally was called the Nuclear Exchange Corporation. They use the term Exchange Value which originated in the idea that Nuexco operated an exchange 'bank' - those with too much uranium could 'bank it', those with short-term needs could borrow from the 'bank'. If the borrower repaid slightly more or less the difference was settled using the 'exchange value'. This became used for longer-term transactions and now settling the monthly value is an important part of Nuexco's activities. The exact nature of the Exchange Value is defined. Now more and more buyers are insisting on spot market related pricing even where this is not meaningfully related to uranium production costs. (U.K.)

Possible Roles of Strigolactones during Leaf Senescence

Directory of Open Access Journals (Sweden)

Yusuke Yamada

2015-09-01

Full Text Available Leaf senescence is a complicated developmental process that involves degenerative changes and nutrient recycling. The progress of leaf senescence is controlled by various environmental cues and plant hormones, including ethylene, jasmonic acid, salicylic acid, abscisic acid, cytokinins, and strigolactones. The production of strigolactones is induced in response to nitrogen and phosphorous deficiency. Strigolactones also accelerate leaf senescence and regulate shoot branching and root architecture. Leaf senescence is actively promoted in a nutrient-poor soil environment, and nutrients are transported from old leaves to young tissues and seeds. Strigolactones might act as important signals in response to nutrient levels in the rhizosphere. In this review, we discuss the possible roles of strigolactones during leaf senescence.

Cotton leaf curl Burewala virus with intact or mutant transcriptional activator proteins: complexity of cotton leaf curl disease.

Science.gov (United States)

Kumar, Jitendra; Gunapati, Samatha; Alok, Anshu; Lalit, Adarsh; Gadre, Rekha; Sharma, Naresh C; Roy, Joy K; Singh, Sudhir P

2015-05-01

Cotton leaf curl disease (CLCuD) is a serious disease of cotton on the Indian subcontinent. In the present study, three cotton leaf curl viruses, cotton leaf curl Burewala virus (CLCuBuV), cotton leaf curl Kokhran virus (CLCuKoV) and cotton leaf curl Multan virus (CLCuMV), and their associated satellites, cotton leaf curl Multan betasatellite (CLCuMB) and cotton leaf curl Multan alphasatellite (CLCuMA), were detected. CLCuBuV with either intact (CLCuBuV-1) or mutant (CLCuBuV-2) transcriptional activator protein (TrAP) were detected in different plants. Agroinoculation with CLCuBuV-1 or CLCuBuV-2 together with CLCuMB and CLCuMA, resulted in typical leaf curling and stunting of tobacco plants. Inoculation with CLCuKoV or an isolate of CLCuMV (CLCuMV-2), together with CLCuMB and CLCuMA, induced severe leaf curling, while the other isolate of CLCuMV (CLCuMV-1), which was recombinant in origin, showed mild leaf curling in tobacco. To investigate the effect of intact or mutant TrAP and also the recombination events, CLCuBuV-1, CLCuBuV-2, CLCuMV-1 or CLCuMV-2 together with the satellites (CLCuMA and CLCuMB) were transferred to cotton via whitefly-mediated transmission. Cotton plants containing CLCuBuV-1, CLCuBuV-2 or CLCuMV-2 together with satellites showed curling and stunting, whereas the plants having CLCuMV-1 and the satellites showed only mild and indistinguishable symptoms. CLCuBuV-1 (intact TrAP) showed severe symptoms in comparison to CLCuBuV-2 (mutant TrAP). The present study reveals that two types of CLCuBuV, one with an intact TrAP and the other with a mutant TrAP, exist in natural infection of cotton in India. Additionally, CLCuMuV-1, which has a recombinant origin, induces mild symptoms in comparison to the other CLCuMV isolates.

Is this Red Spot the Blue Spot (locus ceruleum)?

Energy Technology Data Exchange (ETDEWEB)

Choe, Won Sick; Lee, Yu Kyung; Lee, Min Kyung; Hwang, Kyung Hoon [Gachon University Gil Hospital, Incheon (Korea, Republic of)

2010-06-15

The authors report brain images of 18F-FDG-PET in a case of schizophrenia. The images showed strikingly increased bilateral uptake in the locus ceruleum. The locus ceruleum is called the blue spot and known to be a center of the norepinephrinergic system.

Is this Red Spot the Blue Spot (locus ceruleum)?

International Nuclear Information System (INIS)

Choe, Won Sick; Lee, Yu Kyung; Lee, Min Kyung; Hwang, Kyung Hoon

2010-01-01

The authors report brain images of 18F-FDG-PET in a case of schizophrenia. The images showed strikingly increased bilateral uptake in the locus ceruleum. The locus ceruleum is called the blue spot and known to be a center of the norepinephrinergic system.

The Efficiency of Noni (Morinda citrifolia L.) Essential Oil on the Control of Leaf Spot Caused by Exserohilum turcicum in Maize Culture.

Science.gov (United States)

Silva, Janaina Costa E; Mourão, Dalmarcia de Sousa Carlos; Lima, Fabia Silva de Oliveira; Sarmento, Renato de Almeida; Dalcin, Mateus Sunti; Aguiar, Raimundo Wagner de Souza; Santos, Gil Rodrigues Dos

2017-08-14

The objective of this work was to evaluate the efficiency of noni essential oil on the control of Exserohilum turcicum , a causative agent of Exserohilum spot in maize culture. In the sanitary test 400 seeds were incubated using the blotter test method. For the transmissibility test, the fragments of damaged leaves of seedlings were removed and put into a potato, dextrose and agar (PDA) culture environment. To verify the pathogenicity, Koch´s postulates were performed. In the phytotoxicity test different concentrations of noni oil were applied in maize seedlings. E. turcicum conidia were submitted to different concentrations of noni oil. In the preventive and curative tests noni essential oils were applied before and after the conidia inoculation, respectively. The results revealed the presence of fungi of the genres Aspergillus , Penicillium , Rhizopus , Fusarium , and Exserohilum in the maize seeds. The pathogenicity of E. turcicum and also the transmission of this fungus from the seeds to the maize seedlings was confirmed. The inhibition of conidia germination was proportional to the concentration increase. The preventive application of noni essential oil was the most efficient on the control of Exserohilum spot.

The plant leaf movement analyzer (PALMA): a simple tool for the analysis of periodic cotyledon and leaf movement in Arabidopsis thaliana.

Science.gov (United States)

Wagner, Lucas; Schmal, Christoph; Staiger, Dorothee; Danisman, Selahattin

2017-01-01

The analysis of circadian leaf movement rhythms is a simple yet effective method to study effects of treatments or gene mutations on the circadian clock of plants. Currently, leaf movements are analysed using time lapse photography and subsequent bioinformatics analyses of leaf movements. Programs that are used for this purpose either are able to perform one function (i.e. leaf tip detection or rhythm analysis) or their function is limited to specific computational environments. We developed a leaf movement analysis tool-PALMA-that works in command line and combines image extraction with rhythm analysis using Fast Fourier transformation and non-linear least squares fitting. We validated PALMA in both simulated time series and in experiments using the known short period mutant sensitivity to red light reduced 1 ( srr1 - 1 ). We compared PALMA with two established leaf movement analysis tools and found it to perform equally well. Finally, we tested the effect of reduced iron conditions on the leaf movement rhythms of wild type plants. Here, we found that PALMA successfully detected period lengthening under reduced iron conditions. PALMA correctly estimated the period of both simulated and real-life leaf movement experiments. As a platform-independent console-program that unites both functions needed for the analysis of circadian leaf movements it is a valid alternative to existing leaf movement analysis tools.

First record of spotted wing drosophila Drosophila suzukii (Diptera: Drosophilidae in Montenegro

Directory of Open Access Journals (Sweden)

Snježana Hrnčić

2015-01-01

Full Text Available The spotted wing drosophila Drosophila suzukii Matsumura (Diptera: Drosophilidae is an invasive pest originating from Southeast Asia. It was detected for the first time in Europe in 2008 (Spain and Italy and subsequently in other European countries. It is a highly polyphagous pest that infests healthy, ripening fruit and presents a serious threat to fruit production, particularly of soft skinned fruit. In the first half of October 2013, a new fruit fly species was unexpectedly detected in Tephri traps baited with the three-component female-biased attractant BioLure that is regularly used for monitoring the Mediterranean fruit fly Ceratitis capitata Wiedem. (Diptera: Tephritidae in Montenegro. Brief visual inspection identified the new species as the spotted wing drosophila D. suzukii. The pest was first recorded in several localities on the Montenegrin seacoast around Boka Kotor Bay. After the finding, all Drosophila specimens were collected from traps for further laboratory observation. A quick follow-up monitoring of other Tephri traps was carried out within the next few days on the rest of the seacoast (localities from Tivat to Ulcinj. Additionally, Tephri traps were set up around Lake Skadar and in the city of Podgorica, as well as on fresh fruit markets in Podgorica. The results of this preliminary study showed that D. suzukii was present in all surveyed locations and adults were captured until late December. Both sexes were found in traps with BioLure. Our data show that D. suzukii is present in southern parts of Montenegro and there is a serious threat of its further spreading, particularly towards northern parts of the country where the main raspberry and blueberry production is placed. The results also show that Tephri traps baited with BioLure can be used for detection and monitoring of spotted wing drosophila.

Effects of nitrogen application rate and leaf age on the distribution pattern of leaf SPAD readings in the rice canopy.

Directory of Open Access Journals (Sweden)

Hu Yang

Full Text Available A Soil-Plant Analysis Development (SPAD chlorophyll meter can be used as a simple tool for evaluating N concentration of the leaf and investigating the combined effects of nitrogen rate and leaf age on N distribution. We conducted experiments in a paddy field over two consecutive years (2008-2009 using rice plants treated with six different N application levels. N distribution pattern was determined by SPAD readings based on the temporal dynamics of N concentrations in individual leaves. At 62 days after transplantation (DAT in 2008 and DAT 60 in 2009, leaf SPAD readings increased from the upper to lower in the rice canopy that received N levels of 150 to 375 kg ha(-1The differences in SPAD readings between the upper and lower leaf were larger under higher N application rates. However, as plants grew, this atypical distribution of SPAD readings in canopy leaf quickly reversed to the general order. In addition, temporal dynamics of the leaf SPAD readings (N concentrations were fitted to a piecewise function. In our model, changes in leaf SPAD readings were divided into three stages: growth, functioning, and senescence periods. The leaf growth period lasted approximately 6 days, and cumulative growing days were not affected by N application rates. The leaf functioning period was represented with a relatively stable SPAD reading related to N application rate, and cumulative growing days were extended with increasing N application rates. A quadratic equation was utilized to describe the relationship between SPAD readings and leaf age during the leaf senescence period. The rate of decrease in SPAD readings increased with the age of leaves, but the rate was slowed by N application. As leaves in the lower canopy were physiologically older than leaves in the upper canopy, the rate of decrease in SPAD readings was faster in the lower leaves.

A hairy-leaf gene, BLANKET LEAF, of wild Oryza nivara increases photosynthetic water use efficiency in rice.

Science.gov (United States)

Hamaoka, Norimitsu; Yasui, Hideshi; Yamagata, Yoshiyuki; Inoue, Yoko; Furuya, Naruto; Araki, Takuya; Ueno, Osamu; Yoshimura, Atsushi

2017-12-01

High water use efficiency is essential to water-saving cropping. Morphological traits that affect photosynthetic water use efficiency are not well known. We examined whether leaf hairiness improves photosynthetic water use efficiency in rice. A chromosome segment introgression line (IL-hairy) of wild Oryza nivara (Acc. IRGC105715) with the genetic background of Oryza sativa cultivar 'IR24' had high leaf pubescence (hair). The leaf hairs developed along small vascular bundles. Linkage analysis in BC 5 F 2 and F 3 populations showed that the trait was governed by a single gene, designated BLANKET LEAF (BKL), on chromosome 6. IL-hairy plants had a warmer leaf surface in sunlight, probably due to increased boundary layer resistance. They had a lower transpiration rate under moderate and high light intensities, resulting in higher photosynthetic water use efficiency. Introgression of BKL on chromosome 6 from O. nivara improved photosynthetic water use efficiency in the genetic background of IR24.

Seasonal patterns of leaf gas exchange and water relations in dry rain forest trees of contrasting leaf phenology.

Science.gov (United States)

Choat, Brendan; Ball, Marilyn C; Luly, Jon G; Donnelly, Christine F; Holtum, Joseph A M

2006-05-01

Diurnal and seasonal patterns of leaf gas exchange and water relations were examined in tree species of contrasting leaf phenology growing in a seasonally dry tropical rain forest in north-eastern Australia. Two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., and two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret. were studied. The deciduous species had higher specific leaf areas and maximum photosynthetic rates per leaf dry mass in the wet season than the evergreens. During the transition from wet season to dry season, total canopy area was reduced by 70-90% in the deciduous species and stomatal conductance (g(s)) and assimilation rate (A) were markedly lower in the remaining leaves. Deciduous species maintained daytime leaf water potentials (Psi(L)) at close to or above wet season values by a combination of stomatal regulation and reduction in leaf area. Thus, the timing of leaf drop in deciduous species was not associated with large negative values of daytime Psi(L) (greater than -1.6 MPa) or predawn Psi(L) (greater than -1.0 MPa). The deciduous species appeared sensitive to small perturbations in soil and leaf water status that signalled the onset of drought. The evergreen species were less sensitive to the onset of drought and g(s) values were not significantly lower during the transitional period. In the dry season, the evergreen species maintained their canopies despite increasing water-stress; however, unlike Eucalyptus species from northern Australian savannas, A and g(s) were significantly lower than wet season values.

Spot Pricing When Lagrange Multipliers Are Not Unique

DEFF Research Database (Denmark)

Feng, Donghan; Xu, Zhao; Zhong, Jin

2012-01-01

Classical spot pricing theory is based on multipliers of the primal problem of an optimal market dispatch, i.e., the solution of the dual problem. However, the dual problem of market dispatch may yield multiple solutions. In these circumstances, spot pricing or any standard pricing practice based...... on a strict extension of the principles of spot pricing and surplus allocation, we propose a new pricing methodology that can yield unique, impartial, and robust solution. The new method has been analyzed and compared with other pricing approaches in accordance with spot pricing theory. Case studies support...

Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

Energy Technology Data Exchange (ETDEWEB)

Bouriaud, O. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France); Soudani, K. [Univ. Paris-Sud XI, Dept. d' Ecophysiologie Vegetale, Lab. Ecologie Systematique et Evolution, Orsay Cedex (France); Breda, N. [Inst. National de la Recherche Agronomique, Centre de Recherches Forestieres de Nancy, Champenoux (France)

2003-06-01

Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m{sup 2}{center_dot}g{sup -1}) is used to convert dry leaf litter biomass (g .m{sup -}2) into leaf area per ground unit area (m{sup 2}{center_dot}m{sup -2}). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m{sup 2}) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm{sup 2}{center_dot}g{sup -1}. Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant

Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

International Nuclear Information System (INIS)

Bouriaud, O.; Soudani, K.; Breda, N.

2003-01-01

Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m 2 ·g -1 ) is used to convert dry leaf litter biomass (g .m - 2) into leaf area per ground unit area (m 2 ·m -2 ). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m 2 ) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm 2 ·g -1 . Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant relationship between SLA and soil properties was observed. Both SLA

Effect of nitrogen supply on leaf growth, leaf nitrogen economy and photosynthetic capacity in potato

NARCIS (Netherlands)

Vos, J.; Putten, van der P.E.L.

1998-01-01

Literature reports show little effect of nitrogen supply on radiation use efficiency in potato and in other dicotyledonous C3 species. This paper tests the hypothesis that potato reduces leaf size rather than leaf nitrogen concentration and photosynthetic capacity when nitrogen is in short supply.

Jumping-droplet electronics hot-spot cooling

Science.gov (United States)

Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; Yin, Sabrina L.; Rentauskas, Michelle; Neely, Jason; Pilawa-Podgurski, Robert C. N.; Miljkovic, Nenad

2017-03-01

Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm × 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25 °C air temperature, 20%-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm) and applied heat flux (demonstrated to 13 W/cm2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm2. This work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.

Jumping-droplet electronics hot-spot cooling

International Nuclear Information System (INIS)

Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; Yin, Sabrina L.; Rentauskas, Michelle

2017-01-01

Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm x 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25°C air temperature, 20-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm), and heat flux (demonstrated to 13 W/cm"2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈ 200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm"2. Finally, this work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.

Intraday price dynamics in spot and derivatives markets

Science.gov (United States)

Kim, Jun Sik; Ryu, Doojin

2014-01-01

This study examines intraday relationships among the spot index, index futures, and the implied volatility index based on the VAR(1)-asymmetric BEKK-MGARCH model. Analysis of a high-frequency dataset from the Korean financial market confirms that there is a strong intraday market linkage between the spot index, KOSPI200 futures, and VKOSPI and that asymmetric volatility behaviour is clearly present in the Korean market. The empirical results indicate that the futures return shock affects the spot market more severely than the spot return shock affects the futures market, though there is a bi-directional causal relationship between the spot and futures markets. Our results, based on a high-quality intraday dataset, satisfy both the positive risk-return relationship and asymmetric volatility effect, which are not reconciled in the frameworks of previous studies.

Leaf extraction and analysis framework graphical user interface: segmenting and analyzing the structure of leaf veins and areoles.

Science.gov (United States)

Price, Charles A; Symonova, Olga; Mileyko, Yuriy; Hilley, Troy; Weitz, Joshua S

2011-01-01

Interest in the structure and function of physical biological networks has spurred the development of a number of theoretical models that predict optimal network structures across a broad array of taxonomic groups, from mammals to plants. In many cases, direct tests of predicted network structure are impossible given the lack of suitable empirical methods to quantify physical network geometry with sufficient scope and resolution. There is a long history of empirical methods to quantify the network structure of plants, from roots, to xylem networks in shoots and within leaves. However, with few exceptions, current methods emphasize the analysis of portions of, rather than entire networks. Here, we introduce the Leaf Extraction and Analysis Framework Graphical User Interface (LEAF GUI), a user-assisted software tool that facilitates improved empirical understanding of leaf network structure. LEAF GUI takes images of leaves where veins have been enhanced relative to the background, and following a series of interactive thresholding and cleaning steps, returns a suite of statistics and information on the structure of leaf venation networks and areoles. Metrics include the dimensions, position, and connectivity of all network veins, and the dimensions, shape, and position of the areoles they surround. Available for free download, the LEAF GUI software promises to facilitate improved understanding of the adaptive and ecological significance of leaf vein network structure.