Seeking to understand the mechanisms of tolerance of melon plants under water deficit, this study aimed to evaluate the biochemical behavior of melon cultivars and the allocation of biomass under water deficit. Two experiments were conducted in a shaded environment in the experimental area of the State University of Bahia, Juazeiro / BA; the first was carried out in 2015 and the second in 2016. The experimental design was in randomized blocks, replicated three times, with subdivided plots; the plots consisted of four water application rates (50, 75, 100 and 125% of the crop evapotranspiration), the subplots of two melon cultivars 'Yellow' and 'Piel de Sapo'. The sub-subplots were the sampling periods: 15; 30 and 45 days after transplantation. In the first experiment it was evaluated: total soluble sugars, reducing sugars, total proteins. In the second experiment, in addition to biochemical analyzes, the allocation of biomass of leaves, branches, roots, fruits and root / shoot ratio was evaluated. At the end of both experiments, root proline and aerial part were evaluated. Both cultivars showed similar biochemical behavior, except for the accumulation of proline obtained in the cultivar 'Piel de sapo', which allowed greater biomass allocation to the fruit than the cultivar 'Amarelo'.

The objective of this work was to evaluate the effect of three dehydration/rehydration cycles on the vegetative growth and shoot dry matter of citrus seedlings, as well as seedling acclimatization to this environmental stress. The five following water regimes were evaluated: WR1 (control), WR2, and WR3, with plants kept at 100, 75, and 50% of pot capacity during the three cycles, respectively; and WR4 and WR5, with plants kept at 75, 100, and 75% and 50, 100, and 50% of pot capacity during the first, second, and third cycles, respectively. Relative water content, plant height, length and diameter of the main and secondary branches, angle of leaf insertion in the branch, specific leaf area, leaf chlorophyll content, and dry matter were evaluated. Rehydration after a cycle with 50% of pot capacity did not improve plant growth or dry matter accumulation in relation to the well-hydrated plants of the control. However, after a cycle with 75% of pot capacity, rehydration restores water content, the diameter of the secondary branches, and the angle of leaf insertion. The exposure to successive events of dehydration/rehydration makes the citrus seedlings more resistant to future exposures to water stress.