Physiological and Biochemical Mechanisms of Exogenous Melatonin Regulation of Saline–Alkali Tolerance in Oats

Saline–alkali stress is one of the major factors limiting oat seed germination. The regulatory role melatonin (MT) as a naturally occurring active substance well known, but mechanism MT-mediated intrinsic physiological regulation germination under saline–alkali unclear. Therefore, this study investigated (1) variability different MT soaking concentrations and times on seeds stress, (2) possible mechanisms stress. results showed that vigor was significantly reduced oats inhibited; treatments improved rate, potential, index, root length, germ fresh weight, dry weight; and, overall, treatment exhibited phenomenon “low promotion high inhibition”. 100 μmol·L−1 effectively enhanced activities antioxidant enzymes (SOD, POD, CAT, APX) nonenzymatic antioxidants (GSH AsA), affected AsA-GSH cycle, increased contents osmoregulatory substances (proline, protein, soluble sugar) by reducing levels H2O2, OH−, MDA, thus enhancing tolerance to promoting In conclusion, has positive effect seeds.