不同海拔火绒草叶绿体超微结构的比较

Comparative Study on Chloroplast Ultrastructure of Leontopodium leontopodioides Grown at Different Elevations

利用透射电镜对生长于青藏高原东北部3个不同海拔地区(2300m、2700m和3800m)的火绒草叶绿体超微结构进行了比较观察。结果发现,随着海拔的升高,叶绿体结构差异明显。海拔2300m处,叶绿体呈扁船形,沿细胞壁分布,基粒片层排列整齐,片层可达32层;海拔2700m处,叶绿体呈扁船形,沿细胞壁分布,基粒片层排列不规则,片层下降到十几层,类囊体出现轻微膨大;海拔3800m处,叶绿体呈圆形,位于细胞中央,基粒片层则严重扭曲,片层只有几层,类囊体膨大严重,出现脂质小球。研究表明,火绒草叶绿体结构的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 chloroplast ultrastructures of Leontopodium Leontopodioides distributed in the northeast of Qinghai-Xizang plateau at ahitute of 2300, 2700 and 3800 m were observed respectively with TEM. The result demonstrated that the chloroplast ultrastructure exhibited a varied proclivity in the shape, thylakoid and number of grana lamellae with increasing elevation. In both populations at altitutes of 2300 and 2700 m, they are shuttle-or boat-shaped and scattered along cell wall, but those from lower altitute provided with grana lamellae not less than thirty-two and arranged regularly, whereas those from higher altitute merely previded with gana lamellae not more than twenty and with a slightly swelling thylakoid. In the population at altitude of 3800 m, the chloroplasts become round and locate at the cell center with grana lamellae not more than ten in serionsly distorting arrangement and with an obviously swelling thylakoid. All swelling thylakoids occur a lot of lipid droplets. It was suggested that the chloroplast variations of Leontopodium leontopodioides aforementioned above were caused by long-time stress of habitat factors at different altitudes of Qinghai-Xizang plateau. It is an adaptation of the plant to the environment.