Effect of gibberellin on seed germination and seedling growth of five species of forage seeds

Salt stress is a key factor in limiting seed germination and seedling growth. An appropriate concentration of gibberellin (GA₃) can alleviate the adverse effects of salt stress on forage seeds. This study investigated the alleviating effect of GA₃ on seed germination and growth and determined the best GA₃ concentration to promote seed germination and seedling growth of five species of forage seeds under salt stress. Salt stress was simulated using 100 mmol·L⁻¹ NaCl. The test materials were seeds of Lolium perenne, Echinochloa crusgalli ‘Chaomu1’, Leymus chinensis, Medicago sativa, and Trifolium repens. Seeds were soaked in different concentrations of GA₃. The germination rate, germination index, root length, seedling height, fresh weight, and other indices were measured. Soaking seeds in GA₃ could effectively alleviate the inhibitory effects of salt stress on seed germination and seedling growth of the five forage species. The effects significantly differed among the different GA₃ concentrations (P < 0.05). The GA₃ concentration of 150 mg·L⁻¹ could effectively promote seed germination and seedling growth of L. perenne, L. chinensis, M. sativa, and T. repens. The GA₃ concentration of 100 mg·L⁻¹ effectively promoted seed germination of E. crusgalli, and 50 mg·L⁻¹ GA₃ significantly promoted seedling growth. The study findings will be valuable reference data for forage planting and soil reclamation under salt stress.