Antonio Lucineudo de Oliveira Freire

Estresse salino no crescimento inicial e nutrição mineral de gliricídia (Gliricidia sepium (Jacq.) Kunth ex Steud) em solução nutritiva(1)

Salinity is one of the most limiting factors to plant growth and development. Plant survival in saline environments depends on adaptive processes involving uptake, transport, and distribution of ions in plant organs. To evaluate growth and mineral nutrition of Gliricidia sepium seedlings under saline conditions, an experiment was carried out under nylon-mesh protection, at the Federal University of Campina Grande, in Patos - PB. Seeds were sown in pots containing Hoagland & Arnon nutrient solution with four NaCl levels (0, 100, 200 and 400 mmol L-1), with four replications (1 plant/pot) in a completely randomized design. Sixty days after seedling emergence, the plant height and root, stem and leaf dry matter, and nutrient (N, P, K, Ca, Mg, S and Na) accumulation were measured in the plant tissues. All variables but Na were negatively affected by increasing NaCl levels in the nutrient solution, particularly in the root tissue. Results indicated the sensitivity of Gliricidia sepium to salinity.

Trocas gasosas de plantas de Handroanthus impetiginosus (Mart. ex DC) Mattos submetidas ao déficit hídrico e posterior reidratação

Knowledge of aspects related to the ecophysiology of plant species present in Caatinga is scarce, needing studies that allow the understanding of the adaptations made by plants to be able to survive under conditions of low water availability. Accordingly, this study was developed with the purpose of analyzing the gas exchange of ipe-roxo seedlings subjected to progressive water stress, through the suspension of irrigation, and rehydration. 12 month old plants, growing up in black plastic bags containing 5 kg of substrate, were subjected to two treatments: irrigated and water stress imposed by withholding water. The relative water content, stomatal conductance, transpiration rate, intercellular CO2 concentration, and photosynthetic rates were evaluated daily. After ten days remaining under this stress condition, irrigation was restored, and recovery was evaluated. Drought stress decreased rapidly and also progressively the relative water content, stomatal conductance, transpiration, carboxylation efficiency and photosynthesis of plants. An increase in intercellular CO2 concentration with increase of water stress was observed. After the resumption of water supply, the plants showed recovery of these physiological processes. Water stress did not affect the water efficiency use of plants.

CLONAGEM DE Cnidoscolus quercifolius POR ALPORQUIA

Cnidoscolus quercifolius is an oleaginous plant that can be used for the rehabilitation of degraded areas, feed and food, medicine, sawmill and energy. Clonal propagation of faveleira is a good alternative to seedling production, just like a tool in the plant improvement and to the producers. This study aims to evaluate the efficiency of the air-layering technique on the propagation vegetative of the faveleira, with the view to determine the effect of five concentrations of indolbutyric acid (IBA) and two substrates. We also evaluated the time necessary for the emergence of roots. The experimental design was a randomized complete block design in a 5 x 2 factorial scheme, with 10 repetitions. Each plot consisted of a pruned layers, totaling 100 plots, and treatments combining the five IBA concentrations with the two types of substrates (vermiculite and commercial substrate).There was significant stimulating effect by applying ‘indobultirico’ acid (IBA), to obtain the best results the percentage of air layers roots, root number and root dry mass with a concentration of 6.0 g L -1 . The emergence of the roots on the surface of the substrates occurred at 42 days after the completion of the air layering. There was no significant difference between the substrates for any variable.