the effects of drought stress and exogenous abscisic acid on the expression of ribulose-1, 5-bisphosphate carboxyiase/oxygenase activase (rubisco activase) were examined in wheat (triticum aestivuml.). in response to water stress and abscisic acid, both the levels of endogenous abscisic acid and rubiscoactivase increased in the leaves. immunoblot analysis showed that both drought stress and abs...