石灰岩特有植物圆叶乌桕叶表皮形态特征及其生态适应性研究

Characteristics of Leaf Epidemic and the Association with Their Environmental Adaptation of Triadica rotundifolia,a Limestone Endemic Species

采用扫描电子显微镜和光学显微镜,对石灰岩特有植物圆叶乌桕与同属的乌桕、山乌桕的叶表皮微形态进行观察,比较3个种的叶表皮形态特征,分析圆叶乌桕在石灰岩地区生长的环境适应特点。结果表明:圆叶乌桕叶下表皮细胞小且呈无规则型,细胞排列紧密;气孔集中分布于下表皮,气孔密度和气孔指数相对最小;气孔类型是无规则型,无副卫细胞;圆叶乌桕上下叶表皮有厚角质层和蜡质层,蜡被呈片状和网状。圆叶乌桕的叶表皮微形态特征反映了它对石灰岩生境的适应性较强。

The leaf epidermis of Triadica rotundifolia （Hemsley） Esser-endemic plants in limestone re- gion,and of Triadica sebifera, Triadica cochinchinensis were examined through scanning electron micro- scope （SEM） and light microscope （LM）. By comparing the three species, we analyse T. rotundifolia＇s en- vironmental adaptive mechanisms based on its leaf epidermic morphological characteristics. The results showed that：abaxial cells of T. rotundifolia were small size reversely,with irregular type and closly ar- ranged. The stomatas could only be seen on abaxial epidermis. The stomatal density and index of T. rotun- difolia were lower than that of other two species. Stomatal type was anomocytie without subsidisry cells. Horny layer and wax layer thickly covered on the epidermism,with its waxy coat lamellar and reticulation. All of these implied that T. rotundifolia can adapt to limestone habitats condition.