Tolerância ao déficit hídrico de curta duração em genótipos de cana-de-açúcar e cana energia

Abstract

The water defict of soil is one of the main abiotic stresses which restricts plant growth. Thus, studies aiming at selecting drought tolerant genotypes are primordial for the exploration of agricultural areas. Sugarcane is one crops that has good ability to adapt to edaphoclimatic changes, for larger biomass allocation and consequent production of food, energy, beverages and other. This objective of this study was compare genotypes of sugarcane and energycane in how much of drought tolerance from the study of morphophysiological and biochemical mechanisms. The experimental design was randomiz blocks (DBC), constituited of eight sugarcane genotypes, two commercial (RB92579 and RB0442), two energycane (RB11999 and RB1210282), and four crossing (C90-176 x RB75126, RB04823 x Krakatau, CTC22 x ?, CTC24 x ?), with ten replications, totaling eighty installments. The plants were grown in 30 Liter pots, with soil next field capacity up to 150 days after planting (DAP). Subsequently, irrigation was suspend until the level of severe stress, to 156 DAP, followed by rehydration up to 158 DAP. During the stress and rehydration period was monitor the physiological state of the plants, Leaf samples collected to be used for biochemical analyzes, thus, only after rehydration were the morphological characteristics evaluate. The genotypes submitted to the water deficit reduced gas exchange, decreased photosynthetic efficiency, and increased content of organic solutes and enzymatic activities. The crossing maintained higher Fv / Fm and ΦPSII, and sugarcane induced increased activity of the enzymes Catalase and Ascorbate peroxidase, with the plants under severe stress. The energycane and crossing have a greater degree of tolerance to the water deficit, the best recovery of physiological activities, by rehydration of plants, in relation to the commercial sugarcane that showed to be sensitive to the drought. Besides that, energycanes adjusted osmotically and tolerated the oxidative stress induced by water deficiency.