Abstract: The ultrastructure of chloroplast in the mesophyll cells of three typical alpine halophytes including Potentilla anserina, Polygonum sibiricum and Chenopodium glaucum grown at low temperature and in salt marsh near the Qinghai Lake was studied by using the transmission electron microscope. The result showed that the subcellular structure did not differ between the three halophytes under non-stress condition, but there were a lot of starch grains in the chloroplast of three alpine halophytes, which were usually round or oval in shape arranged along the longitudinal axis of chloroplasts, and the whole starch grains were low in electron-density. Meanwhile, the thylakoid of chloroplasts swelled differently, and some of them even became into cisterna. It suggested that the variations of starch grains in the chloroplast of three alpine halophytes stated above were the result of the long-time stress under the adverse ecological factors such as low temperature, low air pressure, strong radiation, salt marsh, etc., and were an adaptation to the environment.

Key words: Qinghai Lake, halophyte, ultrastructure, starch grai