Mechanism of Dormancy in the Buds and Cambium of Eucommia ulmoides

杜仲形成层休眠机理(英文)

This paper describes changes in the structure of buds and vascular cambium as well as in protein content of one-year-old dormant branches of Eucommia ulmoides Oliv. in water-culture conditions. Results confirm the existence of 2 quiescences (Q1, Q2) and 1 rest (R) phases in this tree during the dormancy period. In the R time, the E. ulmoides cambium was unable to reactivate even though the tree was subjected to exogenous IAA, suitable temperature or required luminosity. Furthermore, pistillate trees entered the dormant phase earlier than staminate ones. The protein content in the bark during Q1 increased significantly ( P < 0.01), but drastically decreased in the R period, before rising up again at the onset of Q2 ( P < 0.01). Even though the change pattern of protein content was similar, its occurrence is much earlier in staminate than in pistillate plants. SDS-PAGE revealed a 'special' protein band of 11.8 kD in the transitional Q1-R-Q2 stages. This 'special' protein bands would be related to the cambial dormancy and to the regulation of the Q1-R-Q2 transition.

对杜仲 (EucommiaulmoidesOliv .)一年生枝条休眠中的芽和维管形成层的结构和蛋白质含量进行了研究 ,探讨了杜仲不同休眠期转化的生理生化机理。结果证实了杜仲树的休眠期包括 2个被动休眠期和一个生理休眠期。在生理休眠期 ,无论用外源IAA处理 ,还是给予适当的温度和光照 ,形成层都不能恢复活动。而且 ,雌株进入各个休眠阶段的时间都比雄株早。树皮中的蛋白质含量在第一被动休眠期间 (Q1)显著地逐步增高 (P <0 .0 1) ,进入生理休眠期 (R)后 ,急剧降低 ,但第二被动休眠期 (Q2 )开始后又显著升高 (P <0 .0 1)。杜仲雌雄株树皮中的蛋白质含量变化趋势基本一致 ,但雄株发生变化的时间比雌株早。SDS_PAGE电泳结果表明 ,在Q1 R Q2的转变期出现一11.8kD的特异蛋白条带。此特异蛋白条带可能与形成层休眠期中各阶段的转变调节有关。