Drought tolerance in apple seedlings through abscisic acid (ABA) regulation

点击翻译按钮获取中文摘要

In this study, we examined the effect of an inhibitor of ABA 8'-hydroxylase (AHI) on drought tolerance in apple seedlings (Malus domestica Borkh.). ABA metabolism, stomatal aperture, water potential, and radical scavenging activity in leaves were all investigated under drought conditions. The result of our observation had shown that the AHI application to seedlings greatly decreased the stomatal aperture in the leaves as in contrast to untreated control samples.However, watering of AHI treated plants re-increased it to the original level. In addition, water potential in AHI-treated leaves remained higher than the one measured in untreated-leaves during the exposure to drought. Drought conditions increased ABA concentrations in both, AHI treated-plants and untreated-plant specimens. Notably, ABA concentrations in AHI-treated leaves were higher than those in untreated-leaves under drought conditions. Although the expression of 9-cis-epoxycarotenoid dioxigenase (MdNCED) genes increased with days of drought stress treatment, in AHI-treated leaves the expression of those genes was significantly lower than in untreated control samples.These results suggest that the prompt stomatal closure through the regulation of ABA 8'-hydroxylase may be required for the plants to survive under relatively long drought conditions.