Relationship between the physiological characters and purification ability of different plants in waters with two trophic levels Ecophysiological response of Calligonum roborovskii to the habitats in different altitudes in north slope of Kunlun Mountain Advance in Studies of Haloxylon Bunge‘s Mechanism of Adapation and Resistance to Drought ECOPHYSIOLOGICAL RESPONSE OF EMMENOPTERYS HENRYI AT DIFFERENT ALTITUDES IN CHINA’S DAPAN MOUNTAIN NATURAL RESERVE