柳属植物叶表特征的研究

STUDIES ON LEAF EPIDERMAL FEATURES OF THE GENUS Salix L.

本文通过对国产柳属植物17个组中的52种及6个变种之叶表特征的观察和研究,发现该项特征在柳属植物的组内与组间呈现出一定的规律性。其中,角质层条状纹饰在各个组内是否出现比较稳定,而气孔分布于上、下表皮还是仅局限于下表皮在组内也是相当稳定的,可以作为划分各组的一项重要特征。探讨了柳属植物气孔复体的类型及分布,测量了气孔指数及大小,并对这些特征在柳属植物内的演化趋势作了一些阐述,发现也具有一定的规律性。在此基础上,与钻天柳的表皮特征做了比较。

About 52 species and 6 vareities among 17 setions of the genus Salix L. have been observed and studied in this paper, based upon their leaf epidermal features such as cuticle striations, covering trichomes, crystal in epidermis, stomatal types and their distribution, frequency, index and size. The presence or absence of cuticle Striations is relatively constant within sections and whether the presence of adaxial as well as abaxial stomata or the presence of stomata only on abaxial epidermis is extremely restricted within Sections. Amphistomatic leaves occur in Sect. Salix L, Sect. Subviminales (Seemen) Schneid., sect. Variegatae Hao, Sect. Cheilophilae Hao and Sect. Helix Dum. , the others have hypostomatic leaves. Stomata randomly orientate over most of the Surface except for areas over veins, and predominantly paracytic in most species of the genus, some species have two kinds of stomatal types, one smaller in size, usually paracytic, and another one larger, abnormal stomata, it is staurocytic or cyclocytic. On the point of view of evolution, in the genus Salix L., leaf epidermal features represent as, primitive species have larger epidermal cells, smaller stomatal index, and without or with very little crystal in epidermis, advanced species smaller on size of epidermal cells, larger stomatal index and with strong or very strong crystal in epidermis. In addition, epidermal features of leaves of Chosenia arbutifolia have shown that, it more relate to primitive sections (such as Sect. Pentandrae) of the genus Salix.