Aplicação foliar de indutor de resistência em feijoeiro comum: efeito sobre desempenho da cultura, qualidade fisiológica e sanitária das sementes

Pós-graduação em Agronomia - FEIS

Relationships between physiological traits and productivity of sugarcane in response to water deficit

The relationships between physiological variables and sugarcane productivity under water deficit conditions were investigated in field studies during 2005 and 2006 in Weslaco, Texas, USA. A total of 78 genotypes and two commercial varieties were studied, one of which was drought-tolerant (TCP93-4245) and the other drought-sensitive (TCP87-3388). All genotypes were subjected to two irrigation regimes: a control well-watered treatment (wet) and a moderate water-deficit stress (dry) treatment for a period of 90 days. Maximum quantum efficiency of photosystem II (F (v)/F (m)), estimated chlorophyll content (SPAD index), leaf temperature (LT), leaf relative water content (RWC) and productivity were measured. The productivity of all genotypes was, on average, affected negatively; however, certain genotypes did not suffer significant reduction. Under water deficit, the productivity of the genotypes was positively and significantly correlated with F (v)/F (m), SPAD index and RWC, while LT had a negative correlation. These findings suggest that genotypes exhibiting traits of high RWC values, high chlorophyll contents and high photosynthetic radiation use efficiency under low moisture availability should be targeted for selection and variety development in programmes aimed at improving sugarcane for drought prone environments.

Resistance of Sugarcane Cultivars to Mahanarva fimbriolata (StAyenl) (Hemiptera: Cercopidae)

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

Ozonated water and chlorine effects on the antioxidant properties of organic and conventional broccoli during postharvest

There is growing interest in studies on sanitizers other than chlorine that can maintain the quality of organic products without affecting their phytochemical content. The effects of using chlorinated and ozonized water treatments, as sanitizing procedures, on the post-harvest quality of organic and conventional broccoli (Brassica oleracea L.) cv. Italica was evaluated. The biochemical parameters (chlorophyll, polyphenols, flavonoids, vitamin C and antioxidant capacity) of the broccoli samples were analyzed at day (C) (arrival of the plant from the field, original features), and 1, 4 and 7 days after harvest. The polyamine analysis was performed on arrival of the plant from the field and on the first and seventh days. The cultivation procedure influenced polyphenol, vitamin C and total chlorophyll content, and the highest value was observed in organic broccoli after the fourth day. Flavenoid content was higher in organic broccoli. The use of ozone appears not to have had an influence on the amount of polyphenolic, flavonoids and vitamin C during storage. Total chlorophyll content was less affected by ozonized water than by the chlorine treatment as at the first and fourth days of storage. The highest content of putrescine was found in conventional broccoli, while the highest levels of spermidine and spermine were found in organic broccoli. Antioxidant capacity was highest in organic broccoli after day 4 of storage and was affected by the bioactive compounds analyzed. Methods of cultivation influenced natural antioxidant and chlorophyll contents in broccoli under cold storage.

Do litter manipulations affect leaf functional traits of savanna woody plants?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Índice SPAD e trocas gasosas ao longo do dia para diferenciação de cana-de-açúcar sob deficiência hídrica

Pós-graduação em Agronomia (Agricultura) - FCA

Interação entre bactérias diazotróficas e doses de n-fertilizante na cultura da cana-de-açúcar

Pós-graduação em Agronomia (Agricultura) - FCA

Morfofisiologia da cunhã cultivada sob estresse salino

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

Physiological changes in eucalyptus hybrids under different irrigation regimes

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

Efeito do extrato aquoso de folhas de guanandi (Calophyllum brasiliense Cambess) no controle do crescimento de Microcystis aeruginosa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Daily photosynthesis, water relations, and ion concentrations of uuonymus irrigated with treated wastewater

Euonymus japonica Thunb. (euonymus) plants were submitted for 9 months to two irrigation treatments using water from different sources: a control (C) water with electrical conductivity (EC) less than 1.2 dS.m(-1) and reclaimed wastewater (RW) with EC approximate to 4 dS.m(-1). At the end of the experiment, no differences in the total dry weight were observed between treatments, whereas the leaf dry mass increased (to the detriment of the root part in RW plants). Throughout the day, the stem water potential (Psi(stem)) of the RW plants was lower than in C, whereas stomatal conductance (g(S)) was slightly reduced in RW from 0800 HR to 1200 HR, but no significant variation in photosynthesis (P-n) or energy conversion efficiency (F'(v)/F'(m)) in photosystem II was detected through the effect of salinity. Gas exchange and fluorescence showed a tendency to increase after midday in plants treated with RW. The photosynthetic behavior and fluorescence of RW plants may have been related to the nitrogen and chlorophyll content of the leaves, confirming the resistance of the photosynthetic mechanism to salinity in this species in these conditions. The toxic effects produced by high concentrations of boron (B), sodium (Na+) and chloride (Cl-) were offset by the effect of other ions like magnesium (Mg2+), potassium (K+), and phosphorus (P) in plants irrigated with RW, thus improving their physiological status without decreasing their ornamental value.

Doses, fontes e épocas de aplicação de nitrogênio em arroz de terras altas cultivado em sistema de semeadura direta

The crop demand by nitrogen varies from one crop to other as well as the amount and application time, and this nutrient can be lost by leaching, volatilization and erosion. The objective of this study was to evaluate doses, sources and times of nitrogen application in rice of high lands cropped in no till system. The work was conducted in Selviria, State of Mato Grosso do Sul, Brazil, in a soil originally under Cerrado vegetation. A randomized blocks design, with the treatments disposed in a factorial scheme 5x3x2 was used. The treatments were constituted by five nitrogen doses (0, 50, 100, 150 and 200 kg ha(-1)), three nitrogen sources (urea; ammonium sulfonitrate plus nitrification inhitor and ammonium sulfate) and two application times (at sowing or at flower bud differentiation), with four repetitions. The sources of nitrogen, as well as the application times had similar effects for most of evaluations. The N doses influenced linearly or with quadratic adjustment the plant height, N leaf content and grains yield, in the two growing seasons. The chlorophyll content and the number of ears m(-2) were affected only, in the first year. The highest yield in the growing season of 2007/08 was obtained with the dose of 149 kg ha(-1) of N. In 2008/09 growing season the increase of N doses provided increment in the grains rice yield, until the maximum dose evaluated (200 kg ha(-1) of N).

Influência do uso de malhas de sombreamento azul, vermelha e preta no desenvolvimento inicial do pepino Taiko

Cucumber (Cucumis sativus L.) is a plant of the Cucurbitaceae family of great commercial importance and their culture is widespread throughout the country. The production of vegetables, high-quality care begins with training ranging from seedlings and shading techniques have an important role in creating environments more conducive to the production of seedlings and many researchers and producers of seedlings have opted for the use of color shading screens, making this way, the wavelength and the amount of incident energy are changed in favor of the plants. Work will be performed at the Department of Forest Sciences, Faculty of Agricultural Sciences, Universidade Estadual Paulista (UNESP), Botucatu campus. The statistical design will be in three blocks, each containing 100 plots of each treatment (seedlings covered with blue screen, red and black). Evaluations of dry mass and height will be made at 7, 14, 21 and 28 days after emergence, and 5 will be selected seedlings of each treatment. At 14 and 28 DAE was measured, and SPAD chlorophyll content at 30 DAE, was evaluated by measuring gas exchange in the second pair of leaves, fully expanded for each plant, which was put in a chamber controlled with infrared gas analyzer (IRGA LI 6400, Licor) to perform measurements of photosynthesis. Treatment with black shading showed statistically better results for total dry matter, plant height, SPAD chlorophyll content and net assimilation of CO2, showing a better quality seedlings and its use is recommended in the cultivation of cucumber Taiko

Validação das unidades arbitrárias de teor de clorofilas obtido em folhas intactas de seringueira

The determination of foliar chlorophyll content is a characteristic that interests ecophysiologists and rural producers. With consideration for practical uses as well as scientific publications, our present work aims to establish equations, for rubber tree leaves, that can convert arbitrary units of expressing chlorophyll content to the international system. Chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chltot) were obtained from intact leaves using a portable chlorophyll detecting instrument. Leaves from different positions on the plant, at various stages of maturity, and representing a large spectrum of pigment concentrations, were collected and analyzed in the field using the Clorofil OG Falkner ® instrument, through four evaluations in forty-five medium leaflets. At the laboratory, leaflets underwent a process of pigment extraction. They were incubated in a water-bath with dimethylsulfoxide (DMSO), dosed in molecular absorption spectrophotometer, and converted into pigment content per unit of fresh weight using conventional equations. The data were evaluated according to the Pearson correlation coefficient and tested with different regression models. For all variables, the linear fit is the most adequate, with correlation coefficients (r) 0.74 for Chlb and 0.88 for Chla and Chltott.

Validação das unidades arbitrárias do teor de clorofilas obtido em folhas intactas de seringueira

The determination of foliar chlorophyll content is a characteristic that interests ecophysiologists and rural producers. With consideration for practical uses as well as scientific publications, our present work aims to establish equations, for rubber tree leaves, that can convert arbitrary units of expressing chlorophyll content to the international system. Chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chltot) were obtained from intact leaves using a portable chlorophyll detecting instrument. Leaves from different positions on the plant, at various stages of maturity, and representing a large spectrum of pigment concentrations, were collected and analyzed in the field using the Clorofil OG Falkner ® instrument, through four evaluations in forty-five medium leaflets. At the laboratory, leaflets underwent a process of pigment extraction. They were incubated in a water-bath with dimethylsulfoxide (DMSO), dosed in molecular absorption spectrophotometer, and converted into pigment content per unit of fresh weight using conventional equations. The data were evaluated according to the Pearson correlation coefficient and tested with different regression models. For all variables, the linear fit is the most adequate, with correlation coefficients (r) 0.74 for Chlb and 0.88 for Chla and Chltott .