细叶楠种子休眠与萌发对低温层积的生理响应

Physiological responses of seed dormancy and germination to cold stratification in Phoebe hui Cheng ex Yang

细叶楠(Phoebe hui Cheng ex Yang)是我国特有的珍贵树种,种子具有生理休眠特性。本文以细叶楠种子为实验材料,研究不同低温层积处理时间(0、20、40、60 d)对细叶楠种子发芽率、营养物质(淀粉、可溶性糖、可溶性蛋白)、过氧化物酶(POD)以及内源激素脱落酸(ABA)、赤霉素(GA_(3))、生长素(IAA)、玉米素核苷(ZR)的影响,分析细叶楠种子萌发与其生理指标的相关性。结果显示:(1)低温层积可以有效打破细叶楠种子的休眠,且处理60 d效果最佳。(2)在低温层积过程,细叶楠种子萌发时间缩短,发芽率提高;种子内淀粉含量降低,可溶性糖和可溶性蛋白含量升高;POD活性上升;ABA含量下降,GA_(3)、IAA含量增加,而ZR含量先上升后下降。(3)细叶楠种子休眠的解除与萌发与其体内营养物质含量、POD活性以及内源激素含量的变化密切相关。

Phoebe hui Cheng ex Yang is a rare and unique tree species in China,and its seeds exhibit physiological dormancy.In this study,we explored the physiological characteristics of P.hui seeds under cold stratification to reveal the response mechanism related to dormancy and germination.Specifically,we used P.hui seeds under different cold stratification time(0,20,40,and 60 d)to study the effects on germination percentage,nutrient levels(starch,soluble sugar,and soluble protein),peroxidase(POD)activity,and endogenous hormone levels(abscisic acid(ABA),gibberellin(GA_(3)),auxin(IAA),and zeatin nucleoside(ZR)),and further analyzed the correlation between seed germination and physiological indicators.Results showed that:(1)Cold stratification effectively broke P.hui seed dormancy,with stratification for 60 d showing the best effect.(2)With cold stratification,seed germination time shortened and germination percentage increased;starch content declined and soluble sugar and protein content increased;POD activity increased;ABA content decreased,GA_(3) and IAA content increased,and ZR content first increased and then decreased.(3)Seed dormancy and germination of P.hui were closely related to changes in nutrient content,POD activity,and endogenous hormone content.