Effect of the density and of the distance of Brachiaria decumbens staff on the initial growth of Coffea arabica L. Seedligns

The aim of this work was to evaluate the interference of three densities (4, 8 and 16 plants/m 2) of Brachiaria decumbens Stapf distributed at three different distances (0, 10 and 20 cm from coffee plants) on the initial growth of Coffea arabica L. seedlings. Dark red Latosoil was used as substrate to fill up 70 liters cement boxes. Coffee seedlings at 15 cm height and 8 leaves stage were planted in each box. B. decumbens seedlings were transplanted when they reached two to four leaves stage. The experimental design was a randomized blocks with ten treatments and three replications. At the end of the experiment were measured, height, leaf number, leaf area, chlorophyll content and dry weight of coffee plants. Dry weight of B. decumbens leaves was also evaluated. The leaf area and leaf dry weight was shown to be more sensitive parameters to the interference of Brachiaria plants. Dry weight of coffee plants were reduced from 60% to 88% when the B. decumbens were transplanted 0 cm from the coffee plant. With distance of 10 cm the reduction of dry weight increased with the increase of the density of the B. decumbens. In the coexistence of the coffee plants with 16 plants/m 2 of B. decumbens, there was a reduction in the dry weight of about 80% at the distances of 0 and 20 cm. Regarding leaf area, the reduction was 47% on the average in the density of 4 plants/m 2 of B. decumbens The reduction in leaf area at other densities was higher at the distance of 0 and 20 cm, and 55% reduction was obtained at the distance of 10 cm.

Avaliação dos teores nutricionais em laranjeira 'Valência', sob fertirrigação

This work aimed to compare fertigation to conventional fertilization in a five-year-old 'Valência' orange orchard, irrigated by microsprinklers. The conventional fertilization, using the recommended dosage for the crop, was parceled out in three during the year. In the fertigation treatments a complete dose, 1/2 and 1/3 of the conventional fertilization dose, parceled out in ten in a year, were used. Trunk circumference and leaf volume, leaf chlorophyll content and fruit yield and quality were measured. For the first year, significant differences among the treatments for the evaluated parameters were not observed; however, it was noticed that fertigation treatments caused less nutritional unbalance, obtained by DRIS. The fertigation treatment using half dosage showed the best result regarding to fruit yield and quality.

Use of Physiological Parameters in Screening Drought Tolerance in Sugarcane Genotypes

The physiological response of four commercial sugarcane genotypes to water stress was evaluated by measuring the photochemical efficiency of the photosystem II (chlorophyll a fluorescence ratio, F v/F m), estimated chlorophyll content (SPAD unit), leaf temperature (LT) and leaf relative water content (RWC). A field trial was established in the subtropical area with well-watered and water-stressed genotypes, in completely randomized blocks with four replicates in a 4 × 2 × 3 factorial design (genotype × irrigation × evaluation date). Physiological measurements were done during a 90 day-period of formative stage of plants. The analysis of variance showed that the interaction of genotype × irrigation × evaluation date had a significant effect for three physiological markers tested, F v/F m, SPAD unit and RWC. Under non-stressed conditions, all genotypes showed similar responses for the four markers. Under water deficiency stress, two drought-tolerant genotypes, HOCP01-523 and TCP89-3505 displayed higher values for F v/F m, SPAD unit and RWC, and lower values for LT, and could be classified as tolerant. It is therefore possible to use these physiological water stress associated traits as scorable marker traits for selecting drought-tolerant sugarcane genotypes in future breeding programs. © 2011 Society for Sugar Research & Promotion.

Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo

The objective of this work was to study the morphological and physiological characteristics of the wheat flag leaf as affected by increasing sowing densities and plant growth regulators application. The experimental design was a split-plot with completely randomized blocks and four replications. Plots were consisted by four sowing densities (30, 50 70 and 90 plants m-1) and the split-plots by plant growth regulators: a product composed by auxin+gebberellin+cytokinin (Ax+GA+CK), Trinexapac-Ethyl e (Ax+GA+CK) + Trinexapac-Ethyl, and a control without application. Dry mass accumulation, plant height, morphological characteristics, SPAD index, nitrogen and photosynthetic pigments contents in the flag leaf were determined. The increase in the sowing density resulted in lower dry mass accumulation and SPAD index of the flag leaves. Trinexapac-Ethyl caused increase in the SPAD index, but the chlorophyll content of the flag leaf was reduced. The SPAD index values were more correlated with the nitrogen than the chlorophyll contents. Ax+GA+CK did not affect flag leaf characteristics in wheat plants.

Crescimento e desordem nutricional em pimenteira malagueta cultivada em soluções nutritivas suprimidas de macronutrientes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Níveis de fertirrigação na avaliação das características morfofisiológicas em mudas de pimenta malagueta

O presente trabalho teve o objetivo de avaliar as características morfofisiológicas de mudas de pimenta malagueta (Capsicum frutescens) sob diferentes níveis de fertirrigação, utilizando-se fertilizante líquido 10-10-10 (N-P-K). O experimento foi realizado na Faculdade de Ciências Agrárias da Universidade Federal da Grande Dourados. O delineamento experimental foi em blocos casualizados (DBC), com seis doses de fertilizante líquido (0; 2,5; 5,0; 10,0; 20,0 e 40 mL L-1) diluídos na água de irrigação e quatro repetições. As mudas foram produzidas em viveiro telado, em bandejas de 128 células preenchidas com substrato. Realizou-se uma fertirrigação, aos 15 dias após a semeadura ( DAS). Avaliou-se, aos 30 dias após a semeadura, o número de folhas, o comprimento da parte aérea e da raiz, a massa fresca e seca da parte aérea e da raiz, a área foliar e o teor de clorofila. A dose de 25 mL L-1 do fertilizante líquido 10-10-10, aplicada via fertirrigação, é recomendada para a produção de mudas de pimenta malagueta, embora tenha havido aumento da massa seca de raízes e parte aérea em dose maior.

Morfofisiologia da cunhã cultivada sob estresse salino

The experiment was developed based on the importance of the nutritional factor cunhã for large and small, animals and on the growth of this forage in typical soils of the semiarid region, generally with salinity from natural or anthropogenic action. The experiment was performed in vessels with a capacity of 5kg prepared in a protected environment with full sunshine in the Department of Technology and Social Sciences (DTCS) of UNEB Campus III in Juazeiro - BA. It evaluated the effect of seven different salt concentrations on increasing levels of irrigation water electrical conductivity - ECw (0, 2, 4, 6, 8, 10 and 12 dS/m), at room temperature. The analysis of culture were taken every seven days observing the number of leaves, stem diameter, plant, plant length and total chlorophyll content at 13; 20; 27; 34 and 40 days after the start of irrigation with saline. The contents of proline, the ratio aero part/Root (AP/Rt), the root length and water content were evaluated in the 40 th day after the onset of treatment. The results showed that the elevation of ECw affected all variables.

Phenotypic and biochemical responses of sugarcane cultivars to glyphosate application

Sugarcane cultivars show varying degrees of herbicide susceptibility, with herbicide effects ranging from no injury to total plant eradication. In this study, phenotypic and biochemical responses to glyphosate were evaluated in three sugarcane cultivars. Herbicide tolerance of the three cultivars (IACSP93-3046, IACSP94-4004 and RB72454) was tested in a greenhouse experiment using a completely randomized design. The experiment consisted of four replications of treatments in a factorial arrangement of 3 cultivars × 6 glyphosate dosages (0, 1,440, 2,160, 2,880, 3,600 and 4,320 g a. e. ha-1). Intoxication symptoms, based on a percentage scale ranging from 0 (no injury) to 100 % (total plant death), and total chlorophyll content were recorded at 1, 2, 3, 6, 7, 10, 20 and 34 days after glyphosate application (DAA). Shikimate dehydrogenase and α-esterase isoenzyme assays were performed at 8, 24, 48, 72 and 144 h after application (HAA). Intoxication symptoms observed at 6 DAA ranged from 5 % at the lowest glyphosate dosage (1,440 g a. e. ha-1) to ~30 % at the highest dosage (4,320 g a. e. ha-1) across all cultivars. IACSP94-4004 and IACSP93-3046 were determined to be the most glyphosate-tolerant cultivars. Reduction in chlorophyll content was observed with high dosages of glyphosate at 6 DAA. The shikimate dehydrogenase banding pattern was generally conserved among cultivars and treatments, with the exception of the IACSP94-4004 cultivar, which showed alterations in the banding pattern of α-esterase after glyphosate application. © 2013 Society for Sugar Research & Promotion.

Improvement of grapevine iron nutrition by a bovine blood-derived compound

Iron (Fe) is essential for chlorophyll formation and plant growth. Irondeficiency chlorosis is a major nutritional disorder in several fruit trees cultivated in calcareous and alkaline soils, reducing fruit yield and quality and causing heavy economic losses. Since chelated Fe, the most widespread fertilizers used for preventing or curing Fe deficiency, pose risks of environmental pollution, the development of sustainable agronomic alternatives represents a priority for the fruit industry. In this work, we investigated the effectiveness of a bovine blood-derived product (BB; 0,125% Fe) for preventing Fe-deficiency in grapevine plants. During the vegetative season 2011 potted plants of five graft combinations: Sangiovese/S4O, Cabernet Sauvignon/S4O and Cabernet Sauvignon/140 Ruggeri, 140 Ruggeri/Cabernet Sauvignon, Vitis riparia/Cabernet Sauvignon were grown on calcareous soil. Soil treatments included: 1) Control; 2) Fe-EDDHA (Fe 6%); 3) Bovine-Blood (5 g/L); 4) Bovine-Blood (20 g/L). With the exception of Cabernet Sauvignon/S4O plants, Fe-EDDHA increased SPAD units (leaf chlorophyll content). Bovine-blood at low concentrations had similar or higher SPAD units than Fe-EDDHA. Increasing concentration resulted in further increases in SPAD units only in some graft combinations. Data highlight the efficiency of Fe blood-compound in the prevention of grapevine Fe-deficiency over one growing season.

Leaf senescence in tomato mutants as affected by irradiance and phytohormones

We explored the interaction between radiation of different wavelength and jasmonic acid (JA) or brassinosteroids (BR) on leaf senescence-induced oxidative stress. Three approaches were used: 1) jasmonic acid insensitive1-1 (jai1-1) and brassinosteroid-deficient [dumpy (dpy)] mutants were treated with red (R) or far-red (FR) radiation; 2) phytochromedeficient aurea (au) and high pigment-1 (hp-1) (radiation exaggerated response) mutants were treated with methyl jasmonate (MeJA) or epibrassinolide (epiBL); and 3) double mutants au jai1-1 and au dpy were produced. Leaf chlorophyll content, lipid peroxidation, and antioxidant enzyme activities were determined. After senescence induction in detached leaves, we verified that the patterns of chlorophyll degradation of hormonal and photomorphogenic mutants were not significantly different in comparison with original cv. Micro-Tom (MT). Moreover, there was no significant change in lipid peroxidation measured as malondialdehyde (MDA) production, as well as catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities in the hormonal mutants. Exogenous BR increased CAT and APX activities in MT, au, and hp-1. As concerns the double mutants, severe reduction in H2O2 production which was not accompanied by changes in MDA content, and CAT and APX activities was observed during senescence in au dpy. The results suggest that JA and BR do not participate in light signaling pathway during leaf senescence-induced oxidative stress. © 2013 Springer Science+Business Media Dordrecht.

Teor de clorofila, danos oxidativos e qualidade de sementes de soja

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tolerância à deficiência hídrica em cultivares de cana-de-açúcar avaliada por meio de variáveis morfofisiológicas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Disponibilidade de fósforo em função da aplicação de calcário e silicatos em solos oxídicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comportamento produtivo do trigo em função da densidade de semeadura e da aplicação de reguladores vegetais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

Pós-graduação em Agronomia (Agricultura) - FCA