Screening Drought Tolerance in Caprifig Varieties in Accordance to Responses of Antioxidant Enzymes

This study was conducted to evaluate antioxidant enzyme activities in four caprifig varieties under drought stress and subsequent rewatering in order to screen drought tolerance. Leaf relative water content and membrane stability index significantly reduced under drought stress. ‘Shah Anjir’ and ‘Khormaei’ were able to preserve the highest relative water content and membrane stability index level during the drought period. Soluble proteins concentration significantly increased under drought stress and the increasing rate was higher in the leaves of ‘Pouz Donbali’, ‘Shah Anjir’ and ‘Khormaei’. Drought stress significantly reduced superoxide dismutase and catalase activities in the leaves of the caprifigs. Ascorbate peroxidase and guaiacol peroxidase activities enhanced in the leaves of ‘Pouz Donbali’, ‘Shah Anjir’ and ‘Khormaei’ under drought stress; however, their activities were significantly higher in ‘Shah Anjir’ and ‘Khormaei’. The results showed the significant effects of peroxidase enzymes in drought tolerance of caprifigs. ‘Khormaei’ and ‘Shah Anjir’ with the highest level of ascorbate peroxidase and guaiacol peroxidase activities under water stress were the most drought tolerant cultivars. The results suggested the possibility of evaluating antioxidant enzymes activities as a physiological marker in drought tolerance screening of caprifig and related species.