Drought resistances and leaf structures of five Oleaceae ornamental plants in Yan'an

【Objective】 The leaf anatomical structures and drought resistances of five Oleaceae ornamental plants in Yan'an urban area were analyzed to improve the understanding on selecting suitable ornamental plants in arid and semiarid regions.【Method】 The leaf anatomical structure of five Oleaceae ornamental plants including Fraxinus chinensis,Syringa oblata,Forsythia viridissima,Ligustrum vicaryi and Forsythia suspensa in Yan'an urban area were observed with paraffin sectioning method and nail enamel seal.Eleven xeromorphic indices including thickness of leaves,thickness of upper epidermis,thickness of lower epidermis,thickness of cuticle,thickness of palisade tissue,thickness of spongy tissue,thickness of vein,stoma density of lower epidermis,and stoma length of lower epidermis were measured by Motic Image Advanced 3.2,and thickness ratio of palisade tissue to spongy tissue and compactness of leaf structure were analyzed.The drought resistances were evaluated by variance analysis,principal component analysis and membership function.【Result】 The results showed that the eleven anatomical characteristics had significant differences between the five Oleaceae ornamental plants,and three typical xeromorphic indices including thickness of palisade tissue,thickness ratio of palisade tissue to spongy tissue and thickness of vein were selected by principal component analysis for drought resistance analysis.【Conclusion】 According to the results of subordinate function value analysis,the drought resistance capabilities of the five Oleaceae ornamental plants were in the order of Fraxinus chinensisSyringa oblataLigustrum vicaryiForsythia viridissimaForsythia suspensa.