Effects of Exogenous Gibberellic Acid on Physiological Characteristics of Hedera nepalensis var. sinensis under Drought Stress

Purpose To investigate the effects of exogenous gibberellic acid (GA₃) on the physiological characteristics of Hedera nepalensis var. sinensis under drought stress.

Methods H. nepalensis var. sinensis cuttings were treated with well-watered and drought stress (10% PEG-6000) as well as sprayed with different mass concentrations of exogenous GA₃ (0, 50 and 100 mg/L). The content of photosynthetic pigments, gas-exchange parameters, chlorophyll fluorescence parameters, malondialdehyde (MDA) content, osmotic regulated substances contents and antioxidant enzyme activities of leaves under different treatments were determined after 15 days.

Results Compared with the well-watered group, the content of photosynthetic pigments and chlorophyll fluorescence parameters of leaves under drought stress decreased significantly; while the contents of MDA, proline, soluble protein, soluble sugar and antioxidant enzyme activities increased significantly. By exogenous spraying of GA₃ with 50 and 100 mg/L, the photosynthetic pigment content, maximum quantum efficiency, quantum efficiency value and antioxidant enzyme activities were significantly improved.

Conclusion Spraying exogenous GA₃ is able to alleviate the damage of drought stress on H. nepalensis var. sinensis and improve its drought resistance.