三种外源激素对干旱胁迫下无芒雀麦种子萌发及幼苗生长的调控效应OA

This study investigated the effects of exogenous hormones on seed germination and seedling growth of Bromus inermis X12 under drought stress.PEG-6000 was used to simulate drought conditions,and a gradient test determined that 25%PEG represented the semi-lethal concentration.On this basis,the alleviating effects of melatonin(MT),methyl jasmonate(MeJA),and gibberellin(GA3)were comparatively evaluated.The results showed that all three exogenous hormones could effectively alleviate the inhibitory effects of drought on seed germination and seedling growth.As hormone concentration increased,the germination percent-age,germination potential,germination index,and vigor index first increased and then decreased,whereas leaf length and root volume continued to increase.After treatment with the highest concentration of MT and GA3,the activities of antioxidant enzymes in leaves and roots reached their peak,and MDA content decreased to the lowest level.As MeJA concentration increased,the activity of antioxidant enzymes initially increased and then decreased.The comprehensive evaluation based on the membership function approach showed that GA3 had the best promotion effect during the germination stage at 288.70 μmol/L and 144.35 μmol/L.The optimal concen-trations at the seedling stage were 200 μmol/L for MT,0.05 μmol/L for MeJA,and 577.41 μmol/L for GA3.