Effects of soaking seeds in salicylic acid on seed germination and seedling growth of Achnatherum inebrians under salt stress

Salt stress is a key environmental factor limiting seed germination, and appropriate concentrations of exogenous hormones can improve the germination ability of seeds under salt stress. In order to select the best concentration of salicylic acid (SA) to promote seed germination and seedling growth of drunken horse grass (Achnatherum inebrians) under salt stress, six SA concentrations were selected to soak the seeds of infected endophytic fungus (E+) and uninfected endophytic fungus (E−) drunken horse grass under 200 mmol·L⁻¹ NaCl stress. The germination rate, germination index, radicle length, germ length, bud water content, and other indicators were determined. The results showed that NaCl inhibited the germination of E+ and E− drunken horse grass seeds and seedling growth. Low concentration (0.05～0.5 mmol·L⁻¹) SA was shown to promote seed germination and seedling growth, while high concentration (1 mmol·L⁻¹) SA showed significant inhibition (P < 0.05). The comprehensive evaluation results of fuzzy mathematics membership function showed that 0.1 and 0.05 mmol·L⁻¹ SA were the best concentrations to promote the seed germination and seedling growth of E+ and E− drunken horse grass, respectively. The main indices used to evaluate the effects of SA on alleviating salt damage in E+ and E− drunken horse grass seeds were radicle length, vigor index, dry weight, germination rate, germination potential, germination index, fresh weight, and seedling water content.