多胺降解产生H2O2在莴苣种子萌发过程中的作用

摘要

Normal lettuce seeds (Lactuca sativa L.)were used to study effects of the H2O2 produced from polyamine degradation in the process of lettuce seed germination after treatments with cyclohexylamine ( CHA, a specific inhibitor of Spd synthase) , aminoguanidine ( AG, an inhibitor of polyamine oxidases) and N, N' -dimethylthiourea ( DMTU, a scavenger of H2O2 ).The results showed that three exogenous polyamines especially 0.5 mmol/L Spd could significantly promote the germination of lettuce seeds.Consistent with the result, CHA had an inhibitory effect on the germination of lettuce seeds.Spd induced germination of lettuce may be relevant to the H2O2 production from polyamine degradation.Because Spd could significantly promote the activity of polyamine oxidases and increased H2O2content of imbibed seeds.DMTU could diminish the promotive effects of Spd on seed germination as it could low Spd induced increase of H2O2.AG also alleviated the Spd promotive effects on seed germination due to its inhibitory role in PAO activity.These results suggest that H2O2 produced from polyamine degradation may be involved in the process of lettuce seed germination.%以正常莴苣(Lactuca sativa L.)"挂丝红"种子为材料,采用外源多胺(Put,Spd,Spm)、亚精胺合酶抑制剂-环已胺(CHA)、多胺氧化酶抑制剂-氨基胍(AG)、H2O2清除剂N,N-二甲基硫脲(DMTU)处理,研究多胺降解产物H2O2在莴苣种子萌发过程中的作用.结果表明,三种外源多胺都可以显著促进莴苣种子的萌发,0.5 mmol/L的Spd作用效果最为显著;与此相对应的是CHA对莴苣种子的萌发有抑制作用;Spd对莴苣种子萌发的促进作用可能与多胺氧化降解产生的H2O2有关.因为(1)Spd可显著促进多胺氧化酶活性和增加吸胀种子的H2O2含量.(2)DMTU可降低Spd对H2O2含量的促进作用而抑制Spd对莴苣种子萌发的促进作用.(3)AG显著抑制Spd对莴苣种子萌发过程中PAO活性,而降低Spd对莴苣种子萌发的促进作用.实验结果暗示多胺氧化降解产生的H2O2参与莴苣种子的萌发过程.