几种高山植物叶绿体淀粉粒的变化特征

Characteristics of Starch Grains in Chloroplast of Five Alpine Plants

利用透射电镜对生长于青藏高原东北部达坂山(海拔3 900 m)的5种高山植物叶绿体超微结构进行了观察。结果发现,在所研究的5种高山植物叶绿体中,淀粉粒数量均较多,淀粉粒呈长椭圆形或圆形,沿叶绿体长轴分布。在珠芽蓼的叶绿体中,淀粉粒的电子密度内外不均匀,外周电子密度低,中央电子密度高。在其余4种高山植物中,淀粉粒的电子密度均较低。另外,在这5种高山植物叶绿体中还出现了脂质小球,其类囊体均出现了不同程度的膨大现象。研究表明,高山植物叶绿体中淀粉粒的这种变化是对逆境的一种适应,是青藏高原特殊生态条件长期胁迫的结果。

The ultrastructures of chloroplast in the mesophyll cells of five species of alpine plants grown on Daban Mountain （an altitude of 3 900 m） in the northeast of Qinghai-Tibet Plateau were observed under TEM. The observations showed that there were a lot of starch grains in the chloroplasts of alpine plants, and the starch grains were usually round or oval in shape arranged along the longitudinal axis of chloroplasts. In the chloroplast of Polygonum viviparum, the central parts of the starch grains were heavy in electron-density, whereas the outer parts were light. In other four species, Gentiana przewalskii, Aconium tanguticum, Pedicularis kansuensis and Delphinium monanthum, the whole starch grains were light in. The abundant lipid droplets were also observed in the chloroplasts with swollen thylakoids in alpine plants. It was suggested that the variations of starch grains in the chloroplast of alpine plants as stated above were the result of the long-time stress under the ecological factors in Qinghai-Tibet Plateau, and were an adaptation to the environment.