关键词: 酸枣, 叶结构, 生态环境, 抗旱

Abstract: The leaf anatomic structure of Zizyphus jujuba var. spinosa from seashore to western arid area (near 37° N latitude) of China were investigated with both a light microscope and a scanning electron microscope. The results showed that all provenances shared the following common features. The distribution of stomata was generally uniform on the abaxial surface, and the type of stomatal apparatus was mainly anomocytic. The upper epidermis was formed by one layer of cells with tight, regular arrangement, and the lower epidermis was also formed by one layer of cells, and the type of anticlinal cell wall on both the upper and on the lower epidermis was straight. In the contrast, there were some differences in the anatomic characteristics among the provenances. With the decrease of water content in the habitats, (1) the stomatas became smaller gradually, and the density of stomata increase gradually; (2) the cells of both the upper and the lower epidermis became smaller gradually; (3) thickness of the upper and the lower cuticle, as well as the thickness of leaf, increased gradually; (4) bifacial leaf changed to isobilateral leaf; (5) the proportion of palisade tissue increased gradually, whereas the spongy tissue decreased; (6) diameter of midrib vessels and of midrib vascular bundles increased gradually; (7) the epidermis ornament changed in an order of smoothness, strip, reticulation, and mountain-like that represented the leaf structural characteristics of xerophytes. The results also showed that the sequence of the drought resistance delicacy was thickness of upper cuticle>density of stomata in proximal surface, size of stomata in proximal surface (length/width), thickness of lower cuticle, thickness of palisade, and thickness of spongy>average length of stomata, average length/width of upper epidermis cells, thickness of leaf, value of CTR, thickness of upper epiderm cell, thickness of lower epidermic cell, layers of palisade>diameter of midrib vascular bundle, average width of stomata, the area of stomata in proximal surface, average length of lower epidermis cells, and average length/width of lower epidermis cells>average length/width of palisade tissue cell.

Key words: Ziziphus jujuba var. spinosa, leaf structure, ecological environment, drought-resistant