Eco-physiological behavior and carbon metabolism in young plants of balsa wood ('Ochroma pyramidal') under three different water regimes

The aim of this research was to evaluate the eco-physiological and biochemical responses in balsa wood plants ('Ochroma pyramidal') under different water regimes. For this purpose, an experiment was conducted in a greenhouse in July 2013. The experimental design was completely randomized in a factorial design (3 4) with three water conditions: control (irrigated), water deficit and flooding in four periods and 5 replications. The physiological parameters evaluated were (predawn leaf water potential ('Ψam'), stomatal conductance (gs) and transpiration (E). The biochemical parameters were (abscisic acid, starch concentrations, total soluble carbohydrate and sucrose). The predawn water potential and the variables of gas exchange were significantly decreased under water deficit and flooding. The abscisic acid concentrations showed increases in the same treatments over time. The starch concentrations decreased significantly in plants under water deficit, representing a decrease of 2.06 times. In plants under flooding stress the starch concentrations decreased 8 times, when compared to the control plants. The contents of total soluble carbohydrate and sucrose increased around 1.65 and 1.54 times in plants under water deficit, respectively. On the other hand, the total soluble carbohydrate was decrease more than 2 times in flooding, when compared to control plants. The water deficit and flooding for twelve days was enough to change the physiological and metabolic processes of balsa wood plants.