Macronutrient accumulation and partioning in fertigated sweet pepper plants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Enzymatic Hydrolysis of Sweet Lupin, Chickpea, and Lentil 11S Globulins Decreases their Antigenic Activity

We investigated the effects of treatments with the enzymes pepsin and trypsin on the in vitro immunological reactivity of the major globulins found in the seeds of sweet lupin, chickpea, and lentil. Polyclonal major globulin-specific antiserum was obtained by immunization of rabbits with a solution of the 11 S globulin of each legume. The globulins were hydrolyzed with pepsin and trypsin for 1, 5, 15, and 30 min. The native globulins and their hydrolysates were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting to identify the polypeptide bands with antigenic activity, and the hypoantigenicity of the hydrolysates was analyzed by enzyme-linked immunosorbent assay. Our results show that enzymatic treatment of the major storage protein (11 S globulin) of sweet lupin, chickpea, and lentil with pepsin or trypsin lead to the formation of large amounts of short peptides and free amino acids that do not allow antibody binding, resulting in a weakened immunoreactivity.

Gas exchange rates at different vapor pressure deficits and water relations of 'Pera' sweet orange plants with citrus variegated chlorosis (CVC)

Net photosynthesis (A) and transpiration rates (E), stomatal conductance (g), water use efficiency (WUE), intrinsic water use efficiency (IWUE) and internal leaf CO2 concentration (C) in response to different vapor pressure deficit (1.2 and 2.5 kPa) were investigated in 'Pera' sweet orange plants affected by citrus variegated chlorosis (CVC), a disease caused by Xylella fastidiosa. All plants were well watered and leaf water potential (Pw) was also measured by the psychrometric technique. Results showed that healthy plants responded to higher vapor pressure deficit (VPD), lowering its net photosynthesis and transpiration rates, and stomatal conductance. However, diseased plants presented no clear response to VPD, showing lower A, E and g for both VPDs studied and very similar values to these variables in healthy plants at the highest VPD. Internal leaf CO2 concentration also decreased for healthy plants when under the highest VPD, and surprisingly, the same pattern of response was found in plants with CVC. These results, the lower Psi(w) and higher WUE values for diseased plants, indicated that this disease may cause stomatal dysfunction and affect the water resistance through xylem vessels, which ultimately may play some role in photosynthetic metabolism. (C) 2003 Elsevier B.V. B.V. All rights reserved.

Rooting of healthy and CVC-affected 'Valência' sweet orange stem cuttings, through the use of plant regulators

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Attractiveness of different sweet and fatty substances to three neotropical tramp ant species (Hymenoptera : Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Leaf gas exchange and fruit yield in sweet orange trees as affected by citrus variegated chlorosis and environmental conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nutrição mineral de plantas ornamentais XI: deficiências de macronutrientes e de boro em Catharanthus Roseus (L.) G. Don e Catharanthus roseus f. albus (sweet) G. Don

Plantas de duas formas botânicas de Catharanthus roseus, de flores lilases e de flores brancas foram cultivadas em soluções nutritivas deficientes em N, P, K, Ca, Mg, S e B, e em solução completa, a fim de se obter o quadro sintomatológico das deficiências, assim como os níveis analíticos de nutrientes nas folhas, caules, raízes e flores. Manifestaram-se sintomas de deficiência claros para todos os nutrientes estudados. Nas plantas de flores lilases, as concentrações de nutrientes na matéria seca de folhas de plantas normais e deficientes foram, respectivamente, para cada nutriente estudado: N(%): 3,53-1,20; P(%): 0,35-0,11; K(%): 2,45-0,76; Ca(%): 1,77-0,81; Mg(%): 0,55-0,46; S(%):0,21-0,12; B(ppm): 382-37. Nas plantas de flores brancas, estas concentrações foram: N(%): 3,78-0,92; P(%): 0,38-0,09; K(%): 2,60-0,86; Ca(%): 1,37-1,15; Mg(%): 0,56-0,44; S(%): 0,10-0,07; B(ppm):372-39.

CO2 assimilation, photosynthetic light response curves, and water relations of 'Pêra' sweet orange plants infected with Xylella fastidiosa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Breakdown of resistance in sweet pepper against Pepper yellow mosaic virus in Brazil

Plantas de Capsicum annuum cv. Magali R, resistentes ao Pepper yellow mosaic virus (PepYMV), exibindo sintomas severos de mosaico amarelo, malformação foliar e subdesenvolvimento foram encontradas em plantios na região de Lins, SP, Brasil, em 2003/04. Partículas semelhantes àquelas do gênero Potyvirus foram observadas em extrato foliar de planta infectada examinado em microscópio eletrônico de transmissão. O extrato foliar também reagiu com anti-soro contra o PepYMV em PTA-ELISA. Além de C. annuum cv. Magali R, esse potyvirus também infectou sistemicamente C. annuum cv. Rubia R, que é resistente ao PepYMV. A seqüência de nucleotídeos de parte do gene da proteína capsidial (CP) desse potyvirus apresentou 96-98% de identidade com a de outros isolados do PepYMV. A seqüência parcial de nucleotídeos da região 3' não traduzida (3' NTR) apresentou 94-96% de identidade com a do PepYMV. Esses resultados são indicativos de que o potyvirus que quebrou a resistência em pimentão é um isolado do PepYMV.

Development and characterization of polymorphic microsatellite markers for the sweet orange (Citrus sinensis L. Osbeck)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative analysis of differentially expressed sequence tags of sweet orange and mandarin infected with Xylella fastidiosa

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A triply cloned strain of Xylella fastidiosa multiplies and induces symptoms of citrus variegated chlorosis in sweet orange

Xylella fastidiosa isolate 8.1,b obtained from a sweet orange tree affected by citrus variegated chlorosis in the state of Sb Paulo, Brazil, and shown in 1993 to be the causal agent of the disease, was cloned by repeated culture in liquid and on solid PW medium, yielding triply cloned strain 9a5c. The eighth and the 16th passages of strain 9a5c were mechanically inoculated into sweet orange plants. Presence of X. fastidiosa in sweet orange leaves of shoots having grown after inoculation (first-flush shoots) was detected by DAS-ELISA and PCR. Thirty-eight days after inoculation, 70% of the 20 inoculated plants rested positive, and all plants gave strong positive reactions 90 days after inoculation. Symptoms first appeared after 3 months and were conspicuous after 5 months. X. fastidiosa was reisolated from sweet orange leaves, 44 days after inoculation. These results indicate that X. fastidiosa strain 9a5c, derived from pathogenic isolate 8.1.b by triply cloning, is also pathogenic, Strain 9a5c is now used for the X. fastidiosa genome sequencing project undertaken on a large scale in Brazil.

Dry matter production of shoots and root density of two cultivars of Lablab purpureus (L.) Sweet

This experiment was conducted in green house conditions to evaluate the DM accumulation in the shoots and in the roots of two cultivars of Lablab purpureus (L.) Sweet. A 2x3 factorial (two cultivars and three evaluation dates) was conducted according to a randomized complete block design with four replications, being the cultivars Highworth and Rongai evaluated at 42, 56, and 70 days after seedling emergence (DASE). The results indicated that the cvs. Highworth and Rongai have the same pattern of DM accumulation in the shoots. In the upper layer of the soil (0-0.20 in) it was found 38.83% and 43.64% of the DM accumulated in the roots down to 2.00 in depth, in the cvs. Highworth and Rongai, respectively. In the deepest layer (1.80-2.00 in) it was found 3.02% and 1.5% of the DM accumulated in the roots of the cvs. Highworth and Rongai, respectively. The root density showed a striking decrease upper layer from the soil (0-0.2 m) down to the depth of 0.60 0.80 in (from 10.83 to 1.75 cm.cm(-3) in the cv. Highworth and from 10.76 to 1.28 cm.cm(-3) in the cv. Rongai). At the bottom layer (1.80-2.00 in) the root density values were 0.98 cm.cm(-3) and 0.59 cm.cm(-3), respectively for the cvs. Highworth and Rongai. The root/shoot ratios were similar in both cvs. and decreased from 42 to 70 DASE showing that the cvs. evaluated had the same dynamics of DM accumulation.