Water deficiency at different developmental stages of Glycine max can improve drought tolerance

Abstract

Developmental windows are specific periods of sensitivity during normal plant development in which a perturbation may be adaptively integrated. In these periods, sub-lethal environmental perturbations may improve the capacity to grow at lethal conditions. The aim of this study was to test the hypothesis that previous non-lethal water deficit applied in different developmental stages in soybean plants could enables them to improve the tolerance to environmental perturbations. In order to test this hypothesis we carried out an experiment with soybean plants submitted to water deficit in different stages of plant development, evaluating yield and physiological aspects. Our results indicated that water deficit experienced on V4 stage (vegetative) induces more suitable response, enabling plants to develop a process of tolerance improvement to a further water shortage period, probably through a reduction of growth, which maintains a conservative strategy of energy use. On the other hand, water deficit in R1 stage (reproductive), increased the plant susceptibility to posterior water withholding. This " strategy" was the opposite of the one employed by plants on V4 stage, i.e., to maintain growth rate probably at the expense of a higher energetic cost.