Effects of Seed Soaking with MeJA on Seed Germination and Seeding Physiological Characteristics of Maize under Drought Stress

LI Zhaoju; XU Xinjuan; QI Hongzhi; WANG Erge; SONG Siyi; WANG Xiaoya; ZHAO Bowen

doi:10.15933/j.cnki.1004-3268.2017.12.007

Abstract：To investigate the mechanism of MeJA to regulate the growth and improve the drought resistance of maize seedlings,the effects of exogenous MeJA with various concentrations on seed germination and seedling physiological characteristics under PEG-6000 simulated drought stress were studied.The results showed that drought stress significantly inhibited seed germination and seeding growth in maize,and seed soaking with low-concentration of MeJA could alleviate the damage caused by drought stress.The germination rate and germination potential under drought stress decreased by 48.1％ and 54.6％ respectively,whereas under seed soaking with 0.25 μmoL/L MeJA increased by 66.3％ and 93.2％ respectively.The root length,plant height,and seeding fresh weight reduced by 22.4％,28.1％,and 47.2％ respectively under drought stress compared with increase by 62.9％,18.5％,28.0％ under 0.25 μmoL/L MeJA.Besides the root showed higher activity under 0.25,2.5 μmoL/L MeJA which was 3.1 and 3.3 times higher than that under drought stress.Compared with water control,drought stress significantly reduced leaf chlorophyll content,but significantly increased the content of leaf sugar and proline.Compared with drought stress treatment,the chlorophyll and proline content under 0.25 μmoL/L MeJA increased by 30.5％ and 17.9％,whereas the sugar content under 0.025 μmoL/L MeJA reduced by 6.5％.The relative conductivity and MDA content under drought stress increased significantly compared with water control,whereas both of them under 0.25 μmoL/L MeJA were 14.7％ and 48.4％ higher than that under drought stress.SOD and POD activity under drought stress increased by 12.6％ and 77.4％ respectively,but CAT activity decreased significantly accounting for 42.0％ of water control.Compared with drought stress,the activity of SOD,POD,and CAT under 0.25 μmoL/L MeJA increased by 25.6％,27.1％,and 65.7％,respectively.Therefore,to a certain extent,exogenous MeJA was able to slow down the damage to maize seedlings caused by drought stress and effectively improve the drought resistance.However,soaking concentration should be strictly controlled,and a low concentration(0.25 μmoL/L) might be appropriate in practice.