Lucas Guilherme Bulegon

Azospirillum brasilense afeta a atividade antioxidante e o teor de pigmentos foliares de Urochloa ruziziensis sob déficit hídrico

Plants need water for growing and sustaining vital activities. Their metabolism changes under water stress, which is one of the greatest challenges in agriculture, especially for crops predisposed to adverse weather conditions. The formation of reactive oxygen species in plants occurs in oxygen-dependent processes, such as photosynthesis. However, in plants subjected to environmental stresses, such as drought, the free ABSTRACT RESUMO

Physiological responses of Urochloa ruziziensis inoculated with Azospirillum brasilense to severe drought and rehydration conditions

This study evaluated the tolerance of U. ruziziensis under severe water stress conditions and its recovery when rehydrated, based in responses of relative leaf water content and gas exchange of the crop. The experiment was conducted in green house in Oxisol. The experimental design was a randomized block design, totaling five treatments, was represented by inoculation of A. brasilense strains AbV5 + AbV6, as follow: seed inoculation, foliar spray application, seed inoculation + foliar spray application, a non-inoculated control with water deficit treatment and a irrigated control without inoculation. Drought was imposed 45 days after sowing, after the vessel was irrigated until saturation of the substrate, by total removal of irrigation for six days, and evaluated three days after the resumption of water, evaluating gravimetric soil moisture, relative leaf water content and gas exchange. Soil moisture showed non variation to treatments non irrigated, but the relative leaf water content was lower in the control without water. The control and the treatment inoculated with A. brasilense in seeds exhibited lower rates of gas exchange. Recovery full of photosynthetic activity occurred three days after rehydration in all treatments. A. brasilense foliar sprayed is efficient to increase the tolerance of U. ruziziensis to water deficit and presented higher photosynthetic rates even under conditions of severe water deficit.

Efeitos residuais da adubação fosfatada sob produtividade e composição bromatológica de forrageiras tropicais

In Brazil today there are large areas of grassland in some stage of degradation due to inadequate handling, particularly with regard to lack of use of phosphate fertilizer. This study aimed to evaluate the productivity and bromatologic composition of three species of tropical forages under the residual effect of phosphorus fertilization. The randomized block design was applied in a 3x5x2 factorial scheme with three forages (Panicum maximum cvs. Tanzania and Mombaca and Brachiaria sp. cv. Mulato), five P rates (0, 40, 80, 120 and 240 kg ha-1), and two cuts (October and November of 2007) with three replicates. The deployment of pasture was held in September 2005, and the area remained under constant grazing and management, with regular cleaning and mowing for two years. In October and November of 2007, the following parameters were evaluated - fresh matter yield (FM), dry matter yield (DM) and contents of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HEM) and mineral matter (MM). Phosphorus fertilization until the maximum dose of 240 kg ha-1 did not promote residual effect on yield and chemical composition of Tanzania, Mombaca and Mulato grasses after two years of application in oxisol, with P fertilizer higher than 4.2 mg dm3, whose averages for the accumulation of DM and CP, NDF and ADF were 9.7 Mg ha-1, 11.8%, 77.8% and 41.3%, respectively.

Efeito da adubação nitrogenada e da sazonalidade na produtividade de Ocimum basilicum L.

The basil (Ocimum basilicum L.) currently is distributed to all continents and was introduced in Brazil with the arrival of Italian colonization. The main parts used for commercialization in Brazil are the fresh or dried leaves. This study aimed to evaluate the effect of doses of nitrogen fertilization for cultivation in spring and fall, the yield characteristics and the productivity of basil, Basil red in the greenhouse. The experimental design was a randomized block, in a factorial 2 x 6 with five replications, where the first factor constituent of five nitrogen doses and one control (0.0; 45.0; 90.0; 135.0; 180.0 and 225.0 kg ha-1 of nitrogen) and by the second, the growing seasons (Spring and Autumn). For the productive characteristics of the cultivar red Basil, it was found that the nitrogen rates between 90.0 to 135.0 kg ha-1 were better, bringing all tested productive characteristics, the spring crop. When observed growing in the autumn, was only fit for the crown projection, fresh weight of shoot and leaf area. When there was significant adjustment, the dose of approximately 110.0 kg ha-1 of nitrogen was that promoted further development of culture. Regarding the growing seasons in the spring we recommended the use of mineral nitrogen fertilization, but when this crop is performed autumn, nitrogen fertilization is not responsive.

Alelopatia de espécies forrageiras sobre a germinação e atividade de peroxidase em alface

Allelopathy is defined as the inhibitory or beneficial effect , direct or indirect, of one plant to another. Thus, it was conducted in the laboratory and under completely randomized design, a bioassay with the aim of evaluating the effect of aqueous extracts, obtained by infusion of dried leaves of oat ( Avena sativa cv . IPR 126), pigeon pea ( Cajanus cajan cv . Mandarin ), ryegrass ( Lolium multiflorum ) and braquiaria ( Brachiaria brizantha cv . Marandu ), on the germination , content of cellular protein and peroxidase activity of lettuce ( Lactuca sativa ). The extracts of pigeon pea and oats reduced germination, which oats had higher allelopathic effect, delaying and reducing the emergence of lettuce seedings. To these treatments also was observed the lower peroxidase activity. The extracts of ryegrass and braquiaria did not show allelopathic effect on germination and enzyme activity of lettuce seedlings.

Synergistic action of Azospirillum brasilense combined with thiamethoxam on the physiological quality of maize seedlings

Plant growth promoting substances, either from biological or chemical origin, are widely used in modern agriculture. In this context, this study evaluated the physiological quality of maize seed treated with thiamethoxam and inoculated with Azospirillum brasilense . Initially, we tested bacterial growth on medium with increasing concentrations of thiamethoxam. We also evaluated the physiological quality of seeds through morphometric measurements, emergence speed index and chlorophyll content by SPAD through a 2x3 factorial arrangement with seed inoculation with A. brasilense (100 mL per 25 kg of seed) and three doses of thiamethoxam (0, 80 and 120 ml per 60,000 seeds). Bacterial population showed a linear reduction according to increasing doses of thiamethoxam. The dose of 120 ml thiamethoxam (42 mg active ingredient) caused a decrease in several variables, while, the inoculation proved a positive activity in seedlings physiological quality. Thus, the inoculation combined with 80 ml thiamethoxam (28 mg active ingredient) show synergistic action in early development in maize seedlings. Keywords: Thiamethoxam, inoculant, plant growth promoting bacteria African Journal of Biotechnology , Vol 13(49) 4501-4507

Physiological maturity of seeds and colorimetry of yellow passion fruit (Passiflora edulis f. flavicarpa Degener)

The passion fruit is among the major fruit crops grown in Brazil, being propagated by seeds due to ease of implementation. However, obtaining seeds of quality is associated with the proper time of collection. Thus, the objective was to determinate the physiological maturity of seeds of passion fruit (