Abscisic acid (ABA) seed soaking induced changes in physiology of two wheat cultivars under water stress

TLDR: Significant decrease in all growth promoting phytohormones, transpiration rate and stomatal conductance were observed while an increase was noticed in endogenous ABA (bound and free) under water stress condition at both growth stages.

Abstract: Wheat production is severely limited by water stress. Exploring water stress resistance physiological mechanisms for different wheat genotypes is of prime importance to find out new drought resistant gene resources. During present investigation two local primitive cultivars of wheat Viz. 011251 and 011393 belonging to arid regions of the country, were used to study the response of cultivars evolved in the natural arid environment to water stress and Abscisic acid (ABA) seed soaking at two important growth stages of the crop (booting and grain filling) in a pot experiment. Changes in endogenous ABA (bound and free) and the growth promoting hormones i.e. trans zeatin ribiside (t-zr), Indole-3-Acetic Acid (IAA) and gibberellins (GA) were monitored. Stomatal conductance and transpiration rate were also measured. Re-watering was done to study the recovery process as well. Significant decrease in all growth promoting phytohormones (IAA, t-zr and GA), transpiration rate and stomatal conductance were observed while an increase was noticed in endogenous ABA (bound and free) under water stress condition at both growth stages. ABA seed soaking helped in mitigating the harmful effects of water stress in both cultivars. But this response was genotype specific and diminished with the progression of the developmental stage of the crop.