Exogenous melatonin induces tolerance to drought stress damage in seedlings and soybean plants

Melatonin (ML) is an indolamine that regulates a wide range of physiological processes as growth roots and shoots, antioxidant enzyme activity, seed germination, photosynthetic efficiency promoting stress tolerance in plants, mitigating the harmful effects abiotic stress. Effects pretreatment soybean (Glycine max (L.) Merr.) seeds with 10, 30, 60 90 μM ML were evaluated seedlings under osmotic measuring germination speed index, root protrusion, growth, DM. Under stress, increased index at 10 (239%), 30 (194%) (189%); 5th-day protrusion by 290%, 214%, 185% 85% (10, 60, respectively). The application (328%), (224%), (265%), (129%) length, followed DM stressed seedlings. Drought reduced efficiency, ROS, enzymatic activities soybean. In second experiment, well-watered (100% field capacity) (WW) drought (DS) plants received 50 ML. rate CO2 assimilation net 28% (2 d after application) 48% (5 application). enzymes activity (catalase peroxidase) enhanced leaf area WW however decreased plants. An number seeds, pod numbers, total mass, observed WW. numbers (27%), (33%) mass (27%) These results demonstrated mitigated negative produced on seedlings, acted inducer, improving yield condition.