Drought Resistance Evaluation and Leaf Structures of Ten Species of Broad-leaved Ornamental Plants in Yan'an Urban Area

The leaf anatomical structure of the ten species of broad-leaved ornamental plants in Yan'an urban area were observed with paraffin sectioning method and nail oil seal.The fifteen xeromorphic indices including thickness of leaves,thickness of upper epidermis,thickness of lower epidermis,cuticle thickness of upper epidermis,cuticle thickness of lower epidermis,thickness of palisade tissue,thickness of spongy tissue,thickness of vascular bundle,thickness of vein,stoma density of lower epidermis,stoma length of lower epidermis,stoma width of lower epidermis were measured and thickness ratio of palisade tissue to spongy tissue,compactness of leaf structure,thickness ratio of vascular bundle to vein were analyzed.Through the methods of variance analysis and principal component analysis.The drought resistance among species were evaluated by membership function.The results showed that:(1)The fifteen xeromorphic indices had significant differences between ten species of broad-leaved ornamental plants,and had higher sensitivity which variation coefficient was 19.34%~73.73%.(2)Ten species of broad-leaved ornamental plants had drought-resistant leaf anatomic structures such as developed epidermis,cuticle,palisade tissue,vein,vascular bundle and so on.The stomatal apparatus were distributed in lower epidermis mostly,Sophora japonica belonged to isobilateral leaf,the rest of species belonged to bifacial leaf.(3)Five typical xeromorphic indices including thickness of upper epidermis,thickness of lower epidermis,thickness of palisade tissue,thickness of bundle,stoma density of lower epidermis could be main indices to evaluate drought resistance comprehensively,the drought resistance capability of ten species of broad-leaved ornamental plants was in the order of Prunus serrulataRosa chinensisPrunus cerasifera cv.pissardiiSophora japonicaSyringa oblataWisteria sinensisParthenocissus tricuspidataEuonymus bungeanusForsythia suspensaBerberis thunbergii cv.atropurpurea.