| The drought resistance characteristics of leaf anatomical structure of Hedysarum mongolicum, Salix psammophila, Caragana microphylla, Caryopteris mongholica and Atriplex canescens were observed under microscope by paraffin-cross section method. The thickness of leaf, cuticle, palisade tissue, vascular tissues and vessel in and diameter were chosen as measuring indicators, which were evaluated by principal components analysis (PCA) and membership function synthetical evaluation method. Analyzed the mechanism of drought resistance and compared the differences on drought resistance ability of these species. Results showed that: (1) the five shrub species all have multiple drought resistance anatomical structure: thickened epidermis cell wall with cuticle, and well-developed palisade and vascular tissues, etc, but without spongy tissue differentiation on both sides of leaves; (2) the drought resistance mechanism type of H. mongolicum, S. psammophila and C. microphylla is water consumption, and the high drought resistance ability is only observed under condign water supply for usage; (3) the drought resistance mechanism type of C. mongholica and A. canescens is endurance, which still have high drought resistance ability under water deficiency; (4) the synthetical carrying capacity of all the indicators and the results of evaluation from membership function values on the synthetical drought resistance characteristics were consistent. The thickness of cuticle and vessel in, the diameter of vessel in and the affinity of leave tissue structures, therefore, were considered as the main indicators of drought resistance characteristics of leaf anatomical structure; (5) The order of drought resistance is C. microphylla > A. canescens > S. psammophila > C. mongholica > H. mongolicum.
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