拟南芥叶柄细胞脱分化与叶绿体超微结构变化

Ultrastructural Study on Chloroplast During Dedifferentiation of Leafstalk of Arabidopsis thaliana

对培养的拟南芥叶柄细胞的超微结构进行观察，培养0～2．0d，叶绿体内淀粉粒的数量和体积逐渐增加；培养2．0～3．0d，叶绿体淀粉粒的数量和体积逐渐减少，细胞中细胞质大量增加，开始形成愈伤组织。以叶绿体及其淀粉粒的变化为依据，将培养的拟南芥叶柄细胞经过脱分化形成愈伤组织的过程划分为前期（培养0～1．5d）、中期（培养1．5～2．0d）和后期（培养3．0d左右）3个阶段；以叶绿体超微结构的变化来界定植物细胞脱分化的过程，为进一步揭示植物细胞脱分化机制提供了依据。

The ultrastructure of chloroplasts of the cultured leafstalk of Arabidopsis thaliana was stud- ied by electronic microscope. The result show that the number and volume of the granulose in chloroplast increase gradually during the first two days. After 2.0 - 3.0 days of leafstalk being cultured, the number and volume of granulose decrease. Afterwards, the cytoplasm of the cells increases and then the cells grow into callus. According to ultrastructural changes of the chloroplasts, the process of dedifferentiation forming the callus is divided into three stages： early stage （0 day to 1.5 day）, medium stage （1.5 day to 2.0 day） and late stage （3.0 day）. It is the first time to define the process of dedifferentiation of plant cells according to ultrastrutural changes of chloroplasts. It is of a great significance for a further exploration of the mechanism of dedifferentiation in plant cell.