矩镰荚苜蓿地下芽越冬期间超微结构适应性变化

Adaptive changes in the young leaf cell ultrastruc⁃ ture of underground-buds in Medicago archiducis-nicolai during overwintering

摘要:

为了研究矩镰荚苜蓿地下芽越冬期超微结构变化，利用透射电镜技术，对该植物越冬期地下芽幼叶细胞进行了观察。结果显示：越冬期间，矩镰荚苜蓿越冬芽幼叶细胞超微结构发生了一系列积极适应低温的变化。细胞内的大体积液泡被分解为小液泡，液泡不断地溶解和吞噬；质体由圆形和椭圆形变形为马蹄状和变形虫状，质体内淀粉粒减少甚至消失；脂滴细胞器增多；由于细胞内发生质壁分离现象，胞间连丝断连且逐渐变模糊甚至消失。分析认为，矩镰荚苜蓿在越冬期间可通过地下芽幼叶细胞器结构的变化，使其自身进入休眠状态，进而抵御寒冷胁迫。

Abstract:

To explore the ultrastructure changes of underground - buds in Medicago archiducis - nicolai during over wintering. young leaf cells of underground buds in M. archiducis-nicolai was investigated by transmission elec- tron microscopy (TEM). The results showed that in order to adapt to cold environment. there were a series of changes in cell ultrastructure. The large volume vacuoles in the cell were decomposed into small vacuoles. which was constantly dissolved and phagocytized. The plastids changed from round and oval to horseshoe and amoeba. and the starch grains were decreased or even disappeared. The number of lipid droplet organelles increased. Due to the separa- tion of plasma wall in cells. plasmodesmata was disconnected and gradually blurred or even disappeared. In conclu- sion. the results suggest that the change of the organelle structure of young leaf cells of underground buds in M. archi- ducis-nicolai makes it enter the dormant state. which could help with the resist to the cold stress.