Produção e teores de nutrientes no capim braquiária adubado com nitrogênio e enxofre

Among the production factors, adequate fertilization is an important tool to raise the productivity of pastoral systems and consequently increase the share of Brazil in the supply chain of primary agricultural products at the global level. The objective of this study was to evaluate the interaction of nitrogen and sulfur fertilization in Brachiaria decumbens Stapf. The experiment in pots with Dystrophic Oxisol was evaluated in a completely randomized design with four replications in a 5 x 3 factorial arrangement, involving five N doses (0, 100, 200, 400, and 800 mg dm-3) in the form of ammonium nitrate and three S doses (0, 20 and 80 mg dm-3) in the form of calcium sulfate, with a total of 15 treatments. In the treatments with low S dose, calcium was provided as calcium chloride, to ensure a homogeneous Ca supply in all treatments. The results showed that the tiller production and dry weight of green leaves and of stems + sheaths and total dry weight were favored by the combination of N and S fertilizer, while the proportion of dry leaves was reduced. Nitrogen fertilization raised the N contents in green leaves and stems + sheaths and reduced K contents in fresh and dry leaves. The response to S rates in the N content of green leaves was quadratic.

Propagation of Camptosema grandiflorum native to Brazil by seeds and cuttings

Camptosema grandiflorum Benth., belonging to Fabaceae, is a voluble climber plant native to Brazil. Plants bloom in autumn-winter, producing long and hanging inflorescences with showy red flowers, which are much visited by hummingbirds. The leaves are also attractive, composed by three leaflets. It can be propagated by seeds or cuttings, but both seed germination and cutting rooting percentages are very low. Thus, the objective of this work was to study the effect of different temperatures on seed germination and of different indolebutyric acid (IBA) concentrations on the rooting of cuttings of C. grandiflorum. The experiment was set up at the São Paulo State University, located in Jaboticabal, São Paulo State, Brazil. The germination study was conducted in an entirely randomized design with six different temperatures (constant at 20, 25, 30 and 35°C; and alternated at 20-30 and 25-35°C, with a photoperiod of 12 hours) and four replications of 25 seeds each, placed in plastic boxes with vermiculite. The percentage of germination and the speed germination index (SGI) were evaluated. An entirely randomized block design was adopted for the cutting rooting evaluation, with four IBA concentrations (0; 1,000; 2,000; and 3,000 mg kg-1) and five replications of ten cuttings each, comprising 200 cuttings. After 30 days from the beginning of the rooting experiment, data referring to rooting percentage, number and length of roots and dry weight of roots were collected. For the seed germination experiment, fastest germination and highest germination percentage (87%) were obtained when seeds were maintained under the constant temperature of 30°C. For the cutting experiment, the concentrations of 2,000 and 3,000 mg kg-1 of IBA promoted the highest rooting percentages (98.5 and 94.1%, respectively) and number of roots. There were no statistical differences among the IBA concentrations for length of roots and dry weight of roots.

Floral induction of mango 'Tommy Atkins' at submedio São Francisco Region, Brazil

Irregular production is a major problem in mango. In an attempt to overcome irregular bearing, effects of two antigibberellins on flowering were evaluated, uniconazole (0.25 g of active ingredient per meter of canopy tree diameter) and paclobutrazol (1.0 g of active ingredient per meter of canopy tree diameter). Treatments were applied as a soil drench using 2 L of solution per tree, in a commercial orchard of 'Tommy Atkins' mango. Treatments were applied after the second vegetative flush commenced, subsequent to pruning. Branch growth was evaluated every 30 days after treatment application up to a maximum period of 90 days. The flowering percentage was recorded at 130 days. Ammonium nitrate (NH4NO3) as a foliar spray (concentration of 0.75%) was applied five times at seven day intervals from 95 to 100 days after treatment application as a dormancy breaking treatment. It was found that both paclobutrazol (PBZ) and uniconazole (UCZ) significantly inhibited the development of vegetative growth compared to the control. Both treatments resulted in identical rates of flowering shoots, 87%; based on results, it can be concluded that the application of antigibberellins (PBZ and UCZ) inhibit vegetative development in mango 'Tommy Atkins', and promote high levels of flowering. Additional tests are being carried out in other farms to confirm these findings, for different cultivars and seasons. © ISHS 2013.

Tolerância à deficiência hídrica de genótipos de arroz de terras altas

Water deficit is one of the environmental factors that cause a great reduction in the upland rice grain yield. The objective of this study was to evaluate genotypes of upland rice with broad genetic diversity for tolerance to this stress and to identify secondary traits for evaluation of this tolerance. Sixty-four genotypes were evaluated during two years at the Experiment Station of EMATER, in Porangatu, GO, under well-watered and water deficit conditions. The genotypes showed differences in grain yield and were influenced differently by the water treatments, both under a mild water deficit in the first year and under a severe one in the second year. The genotype grain yield under water deficiency was significantly and positively correlated with tiller fertility, number of panicles m-2, 100-grain weight, and plant height, and negatively with spikelet sterility and the number of days for the occurrence of 50% panicle emergence. It was also observed that the most productive genotypes under water deficit conditions showed lower leaf temperature, indicating improved water status. Nine genotypes were productive in both water conditions and three were productive only when well-watered.

Inibidores de crescimento em gramados

Well-maintained lawns are comfortable and safe places for leisure activities and sports practice, and they also bring environmental benefits; for example, they reduce soil exposure to erosion and releases atmospheric CO2, thus reducing the greenhouse effect. However, regardless of the purpose of use or the choice of the plant species to form the lawn, the highest costs involve cutting that is needed to keep the turfgrass at its appropriate height. Successive lawn cutting operations are necessary basically because of the vegetative and reproductive growth of turfgrass which, in Brazil, occurs mainly from October to March. Expenditures with successive mechanical cuttings have fostered the search of alternative procedures to keep lawn plants at appropriate height, such as the use of plant growth inhibitors, an increasingly interesting procedure. Since the use of this technology in Brazil is still at its early stage, the aim of this literature review is to examine aspects associated with lawn management by using growth inhibitors. Another alternative is to increase the knowledge of the classification and rational application of the different compounds currently available in the market.

Soil and crop residue CO2-C emission under tillage systems in sugarcane-producing areas of southern Brazil

Appropriate management of agricultural crop residues could result in increases on soil organic carbon (SOC) and help to mitigate gas effect. To distinguish the contributions of SOC and sugarcane (Saccharum spp.) residues to the short-term CO2-C loss, we studied the infl uence of several tillage systems: heavy offset disk harrow (HO), chisel plow (CP), rotary tiller (RT), and sugarcane mill tiller (SM) in 2008, and CP, RT, SM, moldboard (MP), and subsoiler (SUB) in 2009, with and without sugarcane residues relative to no-till (NT) in the sugarcane producing region of Brazil. Soil CO2-C emissions were measured daily for two weeks after tillage using portable soil respiration systems. Daily CO2-C emissions declined after tillage regardless of tillage system. In 2008, total CO2-C from SOC and/or residue decomposition was greater for RT and lowest for CP. In 2009, emission was greatest for MP and CP with residues, and smallest for NT. SOC and residue contributed 47% and 41%, respectively, to total CO2-C emissions. Regarding the estimated emissions from sugarcane residue and SOC decomposition within the measurement period, CO2-C factor was similar to sugarcane residue and soil organic carbon decomposition, depending on the tillage system applied. Our approach may define new emission factors that are associated to tillage operations on bare or sugarcane-residue-covered soils to estimate the total carbon loss.

Avaliação de genótipos de mamona sob níveis de adubação

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)

Produção de plantas de arroz sob a ação de silício e nitrogênio

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

Análise histológica e de microscopia eletrônica do desenvolvimento inicial de jaú (Zungaro jahu)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Anatomia dos órgãos vegetativos de representantes da tribo Cranichideae (Orchidoideae: Orchidaceae)

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

Padrões fenológicos de espécies arbóreas em um fragmento de floresta semidecídua no estado de São Paulo: definição de padrões sazonais e comparação entre anos

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

Macroalgas lóticas do Parque Nacional Chapada dos Veadeiros e arredores (GO): levantamento florístico e distribuição ecológica das comunidades

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

Fenologia e sucesso reprodutivo de Attalea geraensis e Syagrus petraea (Arecaceae) na borda e interior de um fragmento de cerrado

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Caracterização funcional de duas proteínas de Neurospora crassa identificadas em complexos DNA-proteína

Pós-graduação em Biotecnologia - IQ