Melatonin Mitigated Salinity Stress on Alfalfa by Improving Antioxidant Defense and Osmoregulation

Melatonin (MT) is a growth regulator and antioxidant that can resist peroxidation damage on plants caused by environmental stresses. In this study, the alleviation effects of melatonin alfalfa under salt stress were investigated in terms photosynthesis, enzymes, osmoregulation. The seedlings cultured 200 mM NaCl Hoagland solution. Five levels MT (0, 0.1, 0.2, 0.3, 0.4 mM) applied as foliar spray. Generally, spray increased root length, surface area, height, leaf length width, aerial biomass, SPAD readings, content proline soluble protein, activities superoxide dismutase (SOD), peroxidase (POD), catalase (CAT). Malonaldehyde (MDA) was decreased beneficial dosage-dependent, excessive inhibited growth. alleviating more pronounced at 0.3 MT. This study suggested exogenous appropriate ameliorate adverse seedlings.