变温层积过程中华重楼种胚后熟生理生化的变化

Physiological and biochemical change of Paris seed in after-ripening during variable temperature stratification

通过观察和测定变温层积处理过程中华重楼种子胚形态发育进程和体内SOD,POD,CAT,MDH,G-6-PDH 5种酶活性的变化,探究华重楼种子从休眠状态到解除休眠状态过程的酶调控机制.结果显示,华重楼种胚在经过40 d左右的暖温层积（181） ℃之后,进入快速发育阶段,同期种子内在代谢活动显著加强,开始进入生理后熟阶段.在层积第60~80天种子基本完成形态后熟,尔后转入低温层积（41） ℃后进一步促进了种子生理后熟.MDH和G-6-PDH活性在种子层积第40天后分别发生显著的下降和上升,通过调控种子呼吸代谢途径由三羧酸途径为主转为磷酸戊糖途径为主,促进种子解除休眠.SOD,CAT活性在整个层积过程中没有明显波动,但始终维持一定水平,以保证种子活力.POD活性在进入低温层积阶段后显著上升,可能参与调控了种子休眠解除的过程.

In order to explore the dormancy physiological and biochemical mechanism of Paris seeds, the seed embryo growth courses, and the dynamic change of 5 enzymes, include SOD,POD,CAT,MDH,G-6-PDH were measured during variable temperature stratification. The results indicated that Paris seeds embryo grew quickly after 40 d in warm-stratification（181） ℃, at the meantime the metabolic activity was significantly strengthened. These facts showed that Paris seeds turned into physiological after-ripening process. After 60-80 d, the morphological embryo after-ripping process basically completed, and the following cold-stratification（41）℃ furthered Paris seed to finish physiological after-ripening. After 40 d, the activity of MDH decreased while G-6-PDH increased significantly. This showed that the main respiratory pathway of seed changed from TCA to PPP, which benifited breaking seed dormancy. In the whole period of stratification process, the activity variation of SOD and CAT was insignificantly and the activity of POD was enhanced significantly after shifting the seed in cold stratification process. This showed that SOD,CAT had no direct effects on breaking Paris seed dormancy but keeping the seed vigor, while the POD might involve in the process of Paris seed dormancy breaking.keywords：Paris