关键词: 火绒草, 海拔梯度, 叶绿体超微结构FONT

Abstract: The chloroplast ultrastructures of Leontopodium leontopodioides distributed in the northeast of Qinghai-Xizang plateau at altitute 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 provided with gana lamellae not more than twenty and with a slightly swelling thylakoid . In the population at altitude of 3800m, the chloroplasts become round and locate at the cell center with grana lamellae not more than ten in seriously 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 .

Key words: Leontopodium leontopodioides