Abstract: As the loess hilly region is very dry and has a fragile ecosystem,it is essential to screen out suitable drought-tolerant plants for restoring the deteriorating eco-environment.Five plants,korshinsk peashrub,arborvitate,Chinese pine,siberian apricot and Amygdalus tangutica,common in the region were selected and 4 drought-tolerance indices and 2 drought-resistance indexes of the plants obtained.For analysis of the data,the fuzzy membership function method and the grey correlation analysis method were applied to evaluate their drought-tolerance and drought-resistance and effectiveness of the indices as indicator.Results show that the responses of the plants to drought varied shparply with spcies and physiological index.However,sequencing based on a single physiological index of the plants in term of drought-resistance would never get a consistent outcome,indicating that a single index is not adequaate to describe any plant in drought-resistance.The comprehensive evaluation of the five species shows an order of korshinsk peashrub>arborvitae>Chinese pine>siberian apricot>Amygdalus tangutica in terms of drought-resistance.Drought-tolerance indicators,like chlorophyll content,ratio between bound water and free water content,free proline content and glutathione content are closely related to drought-resistance membership degree(>0.06),so they can be accepted as indicators and among them,proline is the most effective.

Key words: drought-tolerance plant, physiological index of drought-tolerance, drought-tolerant evaluation, semiarid are, hilly-gullied area of Loess Plateau