RESEARCH ON THE PHYSIOLOGICAL SPECIALITY AND ADAPTATION OF Liriodendron chinense Competition and Coexistence of Leymus Chinensis and its Main Companion Species in the Songnen Grasslands ANATOMY OF XEROMORPHIC SHRUBS LIVING IN DIFFERENT HABITATS OF HELAN MOUNTAIN Staged strategy of plants in response  to drought stress. ECOLOGICAL ADAPTATION OF SAIGATATARICA ANALYSIS OF DIFFERENCE IN ECOLOGICAL ENVIRONMENT ECOLOGICAL ADAPTATION OF Gordonia acuminata SEEDLINGS IN DIFFERENT LIGHT ENVIRONMENTS