Doses de silício na indução a tolerância ao estresse hídrico em moringa oleífera.

Abstract

Moringa oleífera Lam. is a plant of multiple uses, whether used as human food (flowers, leaves, fruits and seeds) and animal (forage production), water treatment for human consumption, cosmetics and medicinal industry, fuel, paper production. It is considered an exotic tree species that has satisfactorily adapted to the edaphoclimatic conditions of the semiarid region of Northeast Brazil, although the occurrence of water deficit reduces growth, limits development and compromises plant physiology. Silicon is a water deficit mitigating agent. The objective of the present study was to evaluate the effect of silicon doses on the induction of Moringa oleífera tolerance to water stress, on physiology and vegetative growth. The experiment was carried out at the Center for Agricultural and Environmental Sciences of the State University of Paraíba, located in the municipality of Lagoa Seca - PB. The experiment was carried out in a randomized block design, in split plots in a 5x5 double factorial scheme, with five irrigation depths (25, 50, 75, 100 and 125% of ETc) and five doses of silicon (0, 3, 6, 9 and 12 g of silicon dioxide per plant), totaling 25 treatments with four replications, with 100 experimental units which consisted of three useful plants. In the plots were the irrigation depths and in the sub-plots will be the doses of silicon. Irrigation depths exerted a significant influence (p < 0.01) on all variables studied, with the exception of relative water content (TRA), percentage of electrolyte extravasation (% EE) and solar illuminance (IS). On the other hand, the concentrations of silicon dioxide, provided a significant effect for the fourth evaluation of the spad index, chlorophyll a, total chlorophyll, electrolyte extravasation, quantum efficiency of photosystem II. Stem diameter was the only growth variable affected by the interaction between the factors studied.