高温高湿胁迫下茉莉酸甲酯对紫苏种子萌发及生理特性的影响

Effects of Exogenous MeJA on Germination and Physiological Characteristics of Perilla frutescens Seed under High Temperature and Air Humidity Stress

以紫苏品系GS011种子为材料,在温度为50℃、空气相对湿度为95%、时间为12h的胁迫条件下,研究不同浓度(0.05、0.10、0.15、0.20和0.25mmol.L-1)茉莉酸甲酯(MeJA)对紫苏种子萌发、幼苗生长、叶片氧化损伤和抗氧化酶活性的影响。结果表明:0.15mmol.L-1 MeJA处理能显著缓解高温高湿对紫苏种子生长发育造成的胁迫伤害,使紫苏种子发芽率、发芽势、发芽指数、活力指数均达到最大值,分别为40.84%、31.83%、8.83和1.35;同时使其叶片MDA含量最低(0.15μmol.g-1),SOD、CAT、LOX、POD和APX活性均达到最大值,分别为0.27U.mg-1及4.7、5.7、4.9和8.9U.g-1.min-1。研究发现,MeJA在一定程度上能提高SOD等保护酶的活性,缓解高温高湿造成的氧化损伤,有效促进高温高湿胁迫下紫苏种子的萌发和幼苗生长。

The effects of exogenous MeJA at five concentrations of 0. 05,0.10,0.15,0. 20 and 0. Z5 mmol ·L ^-1 on seed germination, seedling growth, the oxidative damage and the protective enzyme activities of the leaves of Perilla frutescens were measured under high air humidity （95%） for 12 hours at 50℃. The re- suits indicated that the damages to the P. frutescens caused by the high temperature and air humidity were most significantly relieved by the 0.15 mmol ·L^-1 MeJA. The seed germination rate,germination potenti- ality,germination index and vigor index increased to the maximum with 40. 840%,31.83% ,8.83 and 1.35, respectively. MDA content decreased to the minimum with 0. 15 /μmol · g ^-1. The protective enzymes of SOD,CAT,LOX,POD and APX increased to the maximum with 0.27 U - mg-1 ,4.7,5.7,4.9 and 8.9 U · g^-1 · min^-1 ,respectively. Based on the data reported,we conclude that MeJA can relieve oxidative damage under high temperature and high air humidity stress, enhance the activity of protective enzymes and stimu- late P. frute.scens seed germination and seedling growth.