Trocas gasosas, índices fisiológicos e acúmulo iônico em plantas jovens de Annona emarginata (Schltdl.) H. Rainer em solução nutritiva

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Photosynthetic and anatomical responses of Eucalyptus grandis leaves to potassium and sodium supply in a field experiment

Although vast areas in tropical regions have weathered soils with low potassium (K) levels, little is known about the effects of K supply on the photosynthetic physiology of trees. This study assessed the effects of K and sodium (Na) supply on the diffusional and biochemical limitations to photosynthesis in Eucalyptus grandis leaves. A field experiment comparing treatments receiving K (+K) or Na (+Na) with a control treatment (C) was set up in a K-deficient soil. The net CO2 assimilation rates were twice as high in +K and 1.6 times higher in +Na than in the C as a result of lower stomatal and mesophyll resistance to CO2 diffusion and higher photosynthetic capacity. The starch content was higher and soluble sugar was lower in +K than in C and +Na, suggesting that K starvation disturbed carbon storage and transport. The specific leaf area, leaf thickness, parenchyma thickness, stomatal size and intercellular air spaces increased in +K and +Na compared to C. Nitrogen and chlorophyll concentrations were also higher in +K and +Na than in C. These results suggest a strong relationship between the K and Na supply to E. grandis trees and the functional and structural limitations to CO2 assimilation rates. © 2013 John Wiley & Sons Ltd.

Effects of soil and foliar application of soluble silicon on mineral nutrition, gas exchange, and growth of potato plants

Silicon can alleviate biotic and abiotic stresses in several crops, and it has beneficial effects on plants under nonstressed conditions. However, there is still doubt about foliar-applied Si efficiency and Si effects on mineral nutrition, physiological processes, and growth of potato (Solanum tuberosum L.) plants under wellwatered conditions. The objective of this study was to evaluate the effect of soil and foliar application of soluble Si on Si accumulation, nutrients, and pigments concentration as well as gas exchange and growth of potato plants. The experiment was conducted under greenhouse conditions in pots containing 35 dm3 of a Typic Acrortox soil. The treatments consisted of a control (no Si application), soil application of soluble Si (50 mg dm-3 Si), and foliar application of soluble Si (three sprays of 1.425 mM Si water solution, prepared with a soluble concentrate stabilized silicic acid), with eight replications. Both soil and foliar application of Si resulted in higher Si accumulation in the whole plant. Foliar application of Si resulted in the greatest Si concentration in leaves, and soil application increased Si concentration in leaves, stems, and roots. Silicon application, regardless of the application method, increased leaf area, specific leaf area, and pigment concentration (chlorophyll a and carotenoids) as well as photosynthesis and transpiration rates of wellwatered potato plants. However, only soil application increased P concentration in leaves and dry weight of leaves and stems. © Crop Science Society of America.

Escala diagramática para quantificação da severidade de manchas em folhas de Eucalyptus globulus Labill. causadas por Teratosphaeria nubilosa (Cooke) Crous & U. Braun

The leaf spot (Mycosphaerella leaf disease = MLD) caused by Teratosphaeria nubilosa has caused damage in eucalypt plantations in southern and southeastern Brazil. The need to assess the disease in the field to evaluate of this damage, efficiency control, evaluation of germplasm induces to the necessity of having a visual scale for evaluation of disease. The objective was to develop a diagrammatic scale for young leaves and one for adult leaves of Eucalyptus globules for MLD. To do so, the leaves collected in the field were scanned for image analysis. The damaged area, the healthy leaf area and the external area of the same scale RGB (Red, Green, Blue) were determined. Subsequently, it was determinate the levels of severity depending on the sample distribution with seven levels for young leaves and six for adult leaves. For the visual acuity test and validate the scale, the leaves were evaluated for severity, with and without scale. With this proposed scales, the assessors showed good accuracy both for young and adult leaves with R2=0,98 and R2=0,80, respectively. The importance of the development of diagrammatic scales for assessing MLD in eucalyptus must to the fact that allows quantification of the symptoms accurately and precisely.

Growth of euterpe oleracea seedlings under different color nets and light conditions

Euterpe oleracea, a native palm to the Amazon, has recognized trading importance because of its fruits and heart of palm. However, it still requires general information on its propagation and cultivation. As light is essential for plant growth, this work aimed to study the effect of different color nets and light conditions on the initial growth of E. oleracea, with the objective to obtain high quality seedlings. The experiment was conducted in Jaboticabal County, São Paulo State, Brazil. The experimental design was entirely randomized, with six treatments (six light conditions: red net with 50% of shading - red Chromatinet®; blue net with 50% of shading - blue Chromatinet®; black nets with 70, 50 or 30% of shading; and full sun) and six replications (six evaluation periods: 30, 60, 90, 120, 150 and 180 days after the beginning of the experiment). Each plot consisted of four pots with one plant per pot, resulting in 144 plants. Seedling growth was monthly evaluated by collecting four plants per replication until the end of the experiment. Shoot length, root length, stem diameter, leaf number, leaf area and root and shoot dry matter were evaluated. The best quality seedlings of E. oleracea were obtained when they were cultivated under the black net with 50% of shading.

Nitrogen and potassium concentrations in the nutrients solution for melon plants growing in coconut fiber without drainage

With the objective of evaluating the effects of N and K concentrations for melon plants, an experiment was carried out from July 1, 2011 to January 3, 2012 in Muzambinho city, Minas Gerais State, Brazil. The Bonus no. 2 was cultivated at the spacing of 1.1 × 0.4. The experimental design was a randomized complete block with three replications in a 4 × 4 factorial scheme with four N concentrations (8, 12, 16, and 20 mmol L-1) and four K concentrations (4, 6, 8, and 10 mmol L-1). The experimental plot constituted of eight plants. It was observed that the leaf levels of N and K, of N-NO3 and of K, and the electrical conductivity (CE) of the substrate increased with the increment of N and K in the nutrients' solution. Substratum pH, in general, was reduced with increments in N concentration and increased with increasing K concentrations in the nutrients' solution. Leaf area increased with increments in N concentration in the nutrients solution. Fertigation with solutions stronger in N (20 mmol L-1) and K (10 mmol L-1) resulted in higher masses for the first (968 g) and the second (951 g) fruits and crop yield (4,425 gm-2). © 2013 Luiz Augusto Gratieri et al.

Comportamento de cultivares de algodoeiro (Gossypium hirsutum L.) ao uso de diferentes doses de cloreto de mepiquat

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determinação dos períodos críticos de interferência das plantas daninhas sobre o milho (Zea mays L. cv C333) em função da redução de espaçamento da cultura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Persistência de cloreto de Mepiquat em plantas de algodão em função da precipitação

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

Adubação fosfatada e lodo de esgoto compostado na nutrição da mamoneira de porte baixo, cultivada sob calagem e silicatagem

Pós-graduação em Agronomia (Agricultura) - FCA

Características morfofisiológicas e agrupamento genético de cana-de-açúcar sob deficiência hídrica

Pós-graduação em Agronomia (Agricultura) - FCA

Cálcio e ethephon no desenvolvimento e produção de óleo essencial de menta (Mentha Piperita L.), cultivada em solução nutritiva

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aspectos ecológicos de um minador foliar em Erythroxylum tortuosum Mart. (Erythroxylaceae): qualidade da planta, anatomia das minas e variação hierárquica de traços vegetais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção de biomassa, rendimento e composição do óleo essencial de manjericão (Ocimum basilicum L.) em função de reguladores vegetais

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

Uso do extrato pirolenhoso: Efeito no solo e nas plantas de tomate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)