低温层积过程中圆齿野鸦椿种子的生理生化变化

The Biochemical and Physiological Changes of Euscaphis konishii Hayata Seeds During the Period of Stratification

通过对不同层积时间圆齿野鸦椿种子萌发及其生理生化变化情况的研究,得出种皮对圆齿野鸦椿种子萌发具有很强的机械障碍,仅通过低温层积不能完全解除种皮的机械障碍。低温层积配合60℃温水浸种能够有效解除休眠。同时通过实验发现,当采取播前温水处理打破种皮机械障碍时,以低温层积90~120d为宜,层积时间过长会导致萌发率降低。通过实验,对低温层积不同时间的圆齿野鸦椿种子生理生化变化情况进行测定,结果表明：随着层积时间增加,可溶性糖含量与G-6-PDH和6-PGDH联合酶活性波动上升,而淀粉含量波动下降。说明种子内含物质相互转化,逐步解除休眠,同时种子呼吸代谢中戊糖磷酸途径所占比重上升。POD活性先逐渐上升,在120d后活性下降,笔者认为这可能是导致层积120d后种子萌发率降低的主原因。

Biochemical and physiological changes and germination characteristics of Euscaphis konishii Hayata seeds were investigated during the period of low temperature stratification.The results showed that the seeds coat presented strong mechanical obstruction.The seed dormancy could not be broken by stratification only. Low temperature stratification plus soaking with 60 ℃ hot water could break seed dormancy effectively. The experiment found that the optimum stratification time for dormancy breaking was between 90 days and 19,0 days.Longer stratification time would make the rate of germi- nation declined.During the period of low-temperature stratification, the content of soluble sugars, the activity of G-6-PDH and 6-PGDH increased fluctuantly while the content of starch declined.It indicated that the seed storage substances might transfer from each other while the dormancy was being broken,the proportion of PPP was rising in respiratory metabolism. The activity of POD increased with peak value at 120 days and decreased afterwards. It might be the main factor of the declined germination after 120 days.