Abstract: Drought resistance of plants affects directly the final result of ecological regeneration on rocky slope. In order to research the mechanism of drought resistance of different plants under sustained drought, three plant species including Poa pratensis, Cynodon dactylon and Trifolium pratense,common in the ecological regeneration on rocky slope, were selected to research the changes of 6 drought resistance indexes including the relative water content, relative conductivity, contents of malondialdehyde, soluble carbohydrate, proline and chlorophyll of the plant leaves with pot culture experiments and chemical analysis. The results showed that all the physiologic and biochemical indexes of the plants changed in varying degrees under drought stress. Fuzzy membership function analysis and the grey correlation analysis were used to research the drought resistance of the 3 plant species and the sensitivity of 6 drought resistance indexes to drought stress. The results revealed that the drought resistance of the 3 species was in an order of C. dactylon ＞ T. pretense ＞ P. prarensis at the early and middle drought stages, but in an order of P. prarensis ＞ C. dactylon ＞ T. pretense at the late stage. The correlation degrees between the 6 drought resistance indexes and the membership degrees were in descending order of 0.708, 0.694, 0.638, 0.630, 0.609 and 0.607, so they can be accepted as the indexes of evaluating and selecting the droughtresistant plant species for ecological regeneration on rocky slope. Among these indexes, chlorophyll and relative water content of plant leaves are the most sensitive to drought stress.  

Key words: drought stress, rocky slope, ecological regeneration, drought resistance, membership function, grey correlation analysis