摘要
杜仲（ＥｕｃｏｍｍｉａｕｌｍｏｉｄｅｓＯｌｉｖ．）形成层３月中旬恢复活动，７月下旬形成层细胞停止分裂，同时停止产生新的韧皮部细胞，但直到８月中旬才停止产生新的木质部细胞。１２月新形成的未成熟韧皮部和木质部细胞都继续分化、成熟。形成层活动周期中，过氧化物酶同工酶的酶谱和酶活性在形成层区域和木质部区域中变化最大。ＰＯⅠ和ＰＯⅡ组同工酶只在春季形成层恢复活动时期存在。ＰＯⅢ的酶活性在夏季减弱，而冬季达到最高水平。酯酶同工酶的酶谱和酶活性亦随形成层的活动状态发生变化。负极端的ＥＳＴⅢ～Ⅴ组酯酶同工酶在生长季节消失，当形成层休眠时又重出现。ＥＳＴⅡ的酶活性最强并在各个时期均存在，它在维管组织的发育分化中可能起重要作用。
The cambium of Eucommia ulmoides Oliv resumed its activities in mid March.It ceased to produce new phoem cells at the end of July,but continued to differentiate into xylem cells until mid August,at which time the cambium became dormant albeit subsequent differentiation of newly formed immature phloem and xylem cells into mature ones continued until December.In consistent with the periodicity of cambial activity,the variability of peroxidase isozyme activity as demonstrated by isozymography was most significant in the cambial region.POⅠ and POⅡ presented only in the spring when cambium activity was resumed.The activity of POⅢ was weakened in summer and increased gradually reaching to the highest level in winter.The variability of esterase isozyme activity in the vascular tissues was in consistent with the periodicity of cambial activity.Isozyme bands of ESTⅢ￣Ⅴ near the negative pole of the zymograph disappeared in specimens collected during growth season and its activity was revived when cambium became dormant.Isozymes of ESTⅡ being the most active and present over time,might play an important role in devolopment and differentiation of vascular tissuess.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
1999年第2期209-216,共8页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
高等学校博士学科点专项科研基金
国家自然科学基金
关键词
杜仲
形成层活动周期
过氧化物
同工酶
Eucommia ulmoides Oliv
periodicity of cambial activity
peroxidase isozyme
esterase isozyme
