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吸胀番茄种子中#beta#-微管蛋白的合成与DNA的复制

郑晓鹰, Bino R J, Bergervoet HW

北京蔬菜研究中心.北京 100081；荷兰植物育种和繁殖技术研究中心.Wageningen

摘要

用免疫检测技术分析了吸胀的番茄种子胚根尖细胞中的#beta#-微管蛋白,并用流体细胞分析仪分析了其细胞核DNA的表现形式,发现种子在吸水8-16h时,即可测得#beta#-微管蛋白的标记,吸水48h标记密度达到高峰。而细胞周期中G2期细胞的数目在吸水24h后才有增加。双向电泳检测,证明种子萌发过程中至少存在3个不同的#beta#-微管蛋白的异构体。用PEG渗调引发处理的种子,#beta#-微管蛋白的合成和DNA复制速度高,反之,老化种子在这两个过程的速度则低。

关键词： 番茄种子; β－微管蛋白; DNA复制; 细胞周期; 免疫检测

#beta#-tubulin synthesis and DNA replication in imbibing seeds of tomato (Lycopersicon esculentum Mill.)

Zheng Xiaoying, Bino R J, Bergervoet HW

Beijing Vegetable Research Center. Beijing 100081； The Netherlands

Abstract

The activation of the cell cycle in embryo root tips of imbibing tomato seeds was studied by immunodetection of #beta#-tubulin, a major component of microtubules, and by flow cytometric analysis of nuclear DNA contents. In dry seeds, #beta#-tubulin was not detectable on Western blots and flow cytometric profiles indicated that the majority of the cells were arrested at phase G1 of the cell cycle. Upon imbibition in water, a clear 55 kD #beta#-tubulin signal was detected within 8 to 16 h while the number of cells in G2 increased after 24 h, suggesting that tubulin synthesis preceded DNA replication. The signal of #beta#-tubulin was stronger at 48 h of imbibition and disappeared once the root tip had protruded through the seed coat. Two-dimensional immunoblots revealed at least three different #beta#-tubulin isotypes. Both #beta#-tubulin synthesis and DNA replication were also induced by priming in PEG. These processes, as well as the seed germination rate, were enhanced upon subsequent imbibition in water, compared with untreated seeds. By contrast, upon imbibition of aged seeds #beta#-tubulin synthesis, DNA replication and germination were delayed. In all seeds, both #beta#-tubulin synthesis and DNA replication preceded visible germination. It is suggested that the activation of these cell cycle-related processes is a prerequisite for tomato seed germination.

Key words: Tomato seed;#beta#-tubulin;DNA replication;Cell cycle;Immunodetection

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引用本文：

郑晓鹰, Bino R J, Bergervoet HW. 吸胀番茄种子中#beta#-微管蛋白的合成与DNA的复制[J]. 生理学报 1996; 48 (4): .

Zheng Xiaoying, Bino R J, Bergervoet HW. #beta#-tubulin synthesis and DNA replication in imbibing seeds of tomato (Lycopersicon esculentum Mill.). Acta Physiol Sin 1996; 48 (4): (in Chinese with English abstract).