Role of exogenous application of abscisic acid ABA in drought tolerance and evaluation of antioxidant activity in durum wheat genotypes

Survival under stressful circumstance depends on the plant’s aptitude to perceive the stimulus, generate and transmit the signals, and initiate various physiological and biochemical changes. This study aims to evaluate the exogenous seed treatment by abscissic acid (ABA) in durum wheat genotypes under water stress conditions. In this investigation, a hydroponic experiment was conducted to evaluate the potential role of exogenously applied abscicic acid in improving drought tolerance in wheat. Three contrasting wheat genotypes were used in this work: Hoggar, Hedba3 and Sigus. Two levels of water stress were induced: 2h and 4h, the aim of this work was to evaluate the action of seed exogenous treatment with ABA for 8 and 16h on physiological and biochemical parameters like stomatal resistance, antioxidant enzyme activity and quantification of ABA by HPLC. The results showed that water stress caused a decrease in endogenous ABA concentration in the roots of the stressed varieties with the exception of Hedba3. Furthermore, after ABA treatment for 16h, the two genotypes Hedba 3 and Hogar showed a higher accumulation of this phytohormone, compared to Sigus variety which marks a decrease in this concentration and which can be explained by the consumption of the ABA in the defense against the ROS.