Abstract:
Drought is one of the major environmental stresses that affect the forage grass planting and productivity in alpine areas. Abscisic acid (ABA), as a class of phytohormones, plays a crucial role in regulating plant growth and development, as well as plant responses to environmental stresses. To investigate the effect of exogenous ABA soaking seeds on seed germination and early seedling growth and development of
Onobrychis viciifolia under the drought condition, the present study firstly utilized different concentrations of ABA to soak
O. viciifolia seeds, and simulated the drought condition with 10% PEG, and then detected and analyzed the seed germination indicators and physiological and biochemical characteristics of early seedlings of
O. viciifolia. The results revealed that the drought stress significantly inhibited the seed germination rate, germination potential, germination index and vigor index of
O. viciifolia, while pretreatment with low-concentration ABA, especially 5 mg·L
-1 and 10mg·L
-1 of ABA, promoted these properties. In addition, pre-soaking seeds with 10mg·L
-1 of ABA could significantly promoted the primary root elongation and root-shoot ratio, increased activities of antioxidant enzymes and the content of osmoregulatory substances, as well as effectively alleviated drought-induced oxidative damage of
O. viciifolia early seedlings. However, seed-soaking with higher concentrations of ABA (>20 mg·L
-1) displayed no effects of the germination and seedling growth of
O. viciifolia. Therefore, it was concluded in the present study that seed-soaking treatment with low concentrations of exogenous ABA could be able to promote seed germination and reduce oxidative damage of
O. viciifolia early seedlings under the drought condition, the result of which will provide a theoretical basis for the popularization of high-quality forage grasses in arid regions.