Abstract
The plant hormone abscisic acid (ABA), as a stress signal, plays important roles in the regulation of plant responses to water stress. Increasing evidence indicates that ABA-enhanced water stress tolerance is related to the induction of antioxidant defense systems by ABA. Current research was conducted to compare the effect of ABA and water stress on wheat seedlings of two genotypes (‘Sarsabz’ and ‘Inqilab-91’). Seeds were allowed to grow under normal irrigation for 7 days. Water Stress was imposed by withholding water for a period of one week and also ABA induction was given for the same period of time. Seedlings were collected from stress and nonstress condition and antioxidant enzymes were estimated. Water stress resulted in a significant enhancement in the activity of peroxidase and reduced levels of catalase compared to ABA treated seedlings in ‘Sarsabz’. Furthermore, ‘Inqilab-91’ showed reversed results and highest reduction was noticed of both the enzymes as compared to control and ABA treated seedlings. These results indicated that the antioxidant activities in two wheat genotypes were greatly affected at water stress. In conclusion, ‘Sarsabz’ reflected more tolerance with respect to antioxidant activities under ABA and water stress condition as compared to ‘Inqilab-91’.
