Gibberellin Increased Yield of Sesbania pea Grown under Saline Soils by Improving Antioxidant Enzyme Activities and Photosynthesis

Crop yield is the ultimate manifestation of all physiological changes of crops and external environmental influence. A controlled study was conducted to investigate the effects of exogenous gibberellin on the morphological and physiological characteristics and yield formation of sesbania pea grown in saline soils. Seeds were presoaked with four levels of Gibberellin (GA(3)) solutions (0, 202.1, 404.2 and 606.3 mu M) for 6 h, and then manually direct-sown with a seeding rate of 45 kg ha(-1). The morphological parameters (plant height, root length, dry weight), photosynthesis (chlorophyll a and b content), the activities of antioxidant enzymes (superoxide dismutase (SOD); peroxidase (POD); catalase (CAT)), the contents of soluble protein and NSC (non-structural carbohydrates), and seed yield increased with the application of exogenous gibberellin, especially at the level of 404.2 mu M GA(3). But GA(3) had no significant effects on 1000-seed weight. Our study suggested that the appropriate application of exogenous gibberellin could improve the yield of sesbania pea grown in saline soils by increasing photosynthesis and antioxidative defense.