Changes in abscisic acid and antioxidant activity in sugar apples under drought conditions

• The drought-tolerant mechanism of sugar apples (Annona squamosa Linn.), which are resistant against drought stress compared to other fruit trees, was investigated.
• The increase of endogenous ABA and ascorbic acid concentrations is associated with the drought-tolerance system in sugar apples.

The drought-tolerant mechanism of sugar apples (Annona squamosa Linn.) was investigated. Changes in endogenous abscisic acid (ABA) and antioxidant activity in sugar apples under drought conditions were analyzed. Endogenous ABA and ascorbic acid concentrations in leaves and fruit increased under drought conditions. In contrast, the stomatal aperture in leaves significantly decreased under drought conditions. The EC50 values of O2− scavenging activity in leaves and fruit under drought conditions were significantly lower than those in the untreated control. These results suggest that the increase of endogenous ABA and ascorbic acid concentrations may be associated with the drought-tolerance system in sugar apples.