茶皂素对油菜幼苗生长发育及抗氧化酶系统的影响

Effects of tea saponin on growth and antioxidant enzyme system of rape

采用溶液培养的方法研究茶皂素对白菜型油菜东京绿(Brassica rapa L.)幼苗生长发育及抗氧化酶系统的影响。结果表明:在5～200mg.L-1的茶皂素浓度范围内,随浓度增加,油菜幼苗的根长表现出先升高后降低的趋势;在5～100mg.L-1的茶皂素浓度范围内,油菜幼苗的株高表现出与根长相同的趋势,但在茶皂素200mg.L-1时株高显著降低;油菜叶片超氧化物歧化酶(SOD)活性逐渐降低;过氧化物酶(POD)活性在低于20mg.L-1时低于对照,随后升高;过氧化氢酶(CAT)活性则仅在浓度为50mg.L-1和100mg.L-1时高于对照;油菜叶片中MDA含量先升高后降低。统计分析发现,浓度范围在5～200mg.L-1的茶皂素对油菜幼苗叶片的生长、抗氧化酶系统和MDA含量没有显著影响,而200mg.L-1显著抑制株高。结果说明了培养液中低于200mg.L-1的茶皂素除降低幼苗株高外,对油菜的苗期是安全的。

As a biological surface active agent,tea saponin is used on leaching repair of soil contaminated by heavy metal.The object of this study was to investigate the effect of tea saponin on plant growth and antioxidant enzyme system.Different concentrations of tea saponin were tested in liquid culture using Brassica rapa L.cv Tokyo Green seedlings.Results showed that tea saponin had no significant effect on root length of the seedlings under 200mg·L-1.But when the chemical concentration reached 200 mg·L-1,the plant height was significantly inhibited.The activity of SOD（superoxide dismutase） in leaves was gradually decreased in tea saponin liquid.The POD（peroxidase） activity was decreased at concentrations lower than 20mg·L-1 and then became higher than no chemical control.On the contrary,the CAT（catalase） activities were higher than control only when tea saponin concentration were 50mg·L-1 and 100mg·L-1.The MDA（malondialdehyde） contents varied in the liquids.Statistically,there was no significant influence of tea saponin at 5 to 200mg·L-1 on antioxidant enzyme system and MDA content of Tokyo Green seedlings.It suggested that tea saponin was safe to rape seedling under 200mg·L-1.