豌豆顶芽衰老过程中的显微、超微结构和nDNA的变化  

Microstructural,Ultrastructural and nDNA Changes of the Cells during the Apical Bud Senescence in Pea

作　　者：石鹏[1] 王大勇[1] 崔克明[1] 

机构地区：[1]北京大学生命科学学院,北京100871

出　　处：《北京大学学报（自然科学版）》2002年第2期204-211,共8页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家自然科学基金 ( 3 9770 0 4 8;3 0 0 70 614 );国家重点基础研究和发展规划项目 (G19990 160 0 2 )资助项目

摘　　要：显微、超微结构研究表明 ,短日照条件下豌豆顶芽的衰老过程是从营养生长锥向花芽的转化 ,而用DNA原位末端标记 (TUNEL)、Caspase 8WesternBlot和 14 0bpDNA片断积累的试验结果证明 ,转化为花芽的整个生长锥细胞发生了编程性死亡 (PCD) ,而且其最顶端部分细胞首先发生PCD ,而顶端周围的分生组织细胞逐渐分化出花芽的各部分 ,但顶芽最后并没有发育成为完整的花 ,所有细胞就都发生PCD 。When pea ( Pisum sativum L.,Alaska strain) was grown in short\|day conditions,the apical bud senescence started with the transformation of the bud from vegetative to reproductive growth.DNA fragmentation was detected during the senescence using the terminal deoxynucleotidyl transferase (TdT)\|mediated dUTP nick end in situ labeling (TUNEL) method.The cell ultrastructural changes were similar to apoptosis in animal cells:the apical meristemetic cells underwent the programmed cell death (PCD).This was first detected in the apex cells of apical meristem,while peripheral cells differentiated gradually into different parts of a floral bud.But all the cells in the floral bud were subjected to the PCD process before it developed into a complete flower. 140?bp DNA fragment was found to deposit in apical bud during the plant development.The most important role of Caspase\|8 was detected by Western blot,and the expression of the procaspase\|8 was time\|related with the DNA frgmentation and the transformation from vegetative to the reproductive growth.These results suggested that PCD was an active process during the differentiation of apical meristem,and the senescence observed in the apical bud was due to the PCD process.

关 键 词：豌豆 顶芽 衰老过程 细胞编程性死亡 衰老机理 显微结构 超显微结构mDNA积累 

分 类 号：Q944.33[生物学—植物学]