Leaf anatomical structure based drought resistance evaluation of 11 urban forest plants in Xining city

【Objective】The leaf anatomical structures of 11 urban forest plants in a semi-arid city Xining were evaluated to analyze their drought resistances.【Method】In July 2012,healthy mature leaves from four directions of 11 tested plants in the Culture Park,Xining were picked.Paraffin sectioning method and nail oil seal were used to make permanent loadings.Thickness of leaves,thickness of upper epidermis,thickness of lower epidermis,cuticle thickness of upper epidermis,layers of palisade tissue,thickness of palisade tissue,thickness of spongy tissue,thickness of vein,and stoma density of lower epidermis were measured by Motic Image Advanced 3.2and thickness ratio of palisade tissue to spongy tissue and compactness of leaf structure were calculated.Variance analysis,principal component analysis and membership function were used to evaluate the drought resistances of the 11 plants.【Result】Leaves of all 11 plants had anatomical structures in resistance to arid environment,including the obvious cuticle,developed palisade tissue and veins,and pores with large density.Except the layers of palisade tissue,all xeromorphic indices had signifi-cant differences between the 11 plants.Four typical xeromorphic indices including thickness of palisade tissue,thickness of spongy tissue,cuticle of upper epidermis.and stoma density of lower epidermis were screened by principal component analysis.【Conclusion】The drought resistances of the 11 plants were in a decreasing order of Prunus davidianaCaragana korshinskiiUlmus laevisFallopia aubertiiSiberian apricotPopulus hopeiensisCaryopteris clandonensisElaeagnus angustifoliaHippophae rhamnoidesViburnum farreriLigustrum obtusifolium.