海南七仙岭7种卷柏属植物的微观形态与生境间的关系分析

Analysis of the Relationship between Microscopic Morphology and Habitat of Seven Selaginella Species in Qixianling,Hainan

为探讨生境对卷柏属(Selaginella)植物微观形态的影响,利用扫描电子显微镜对海南七仙岭采集的7种卷柏属植物的侧叶、中叶、孢子叶的叶表皮形态以及小孢子形态进行全面观察分析,并计算气孔器大小、气孔密度、孢子大小等,比较分析其微观形态的区别及微形态与生境间的关系,为卷柏属植物的分类提供依据。结果显示:(1)同种卷柏属植物的侧叶、中叶与孢子叶在叶表皮形态上具明显差异,尤其是孢子叶上的气孔与营养叶相对较小且稀疏,与孢子叶的繁殖功能相符合。(2)不同种卷柏属植物的叶表皮特征也明显不同,主要表现在叶缘刺、气孔和瘤状突起上,表明这些特征可以作为卷柏属植物种间区分的依据。(3)卷柏属植物的小孢子形态稳定,纹饰多样;部分种间的小孢子形态相似,但可通过纹饰类型、裂缝的曲直进行区分。(4)琼海卷柏的小孢子具有独特的网状纹饰,暗示其具有独特的演化途径。(5)卷柏属植物叶表皮的气孔特征、瘤状突起特征,小孢子的颜色、纹饰,与海拔、生境的湿度有一定的相关性,但其形成机理有待进一步研究。

In order to explore the influence of habitat on the micromorphology of Selaginella plants,we used a scanning electron microscope to comprehensively observe the morphological characteristics of lateral leaves,middle leaves,fertile leaves and microspores of seven Selaginella species collected in Qixianling,Hainan,and measured and calculated stomatal size,stomatal density,spore size.Differences in micromorphology and the relationship between micromorphology and habitat were compared and analyzed to provide a reliable basis for the classification of Selaginella species.Results show that:(1)lateral leaves,middle leaves and fertile leaves of the same species of Selaginella have obvious differences in leaf epidermal morphology,especially the stomata on fertile leaves are smaller and sparer than those of sterile leaves,which is consistent to the reproductive function of fertile leaves.(2)The leaf epidermis characteristics of different species of Selaginella are also distinct,mainly in leaf margin thorns,stomata and tumor-like bulges,indicating that these characteristics can be used as the basis for the distinction between species of Selaginella.(3)The microspores of Selaginella are stable in morphology and diverse in texture;the microspores in some species are similar in shape,but are distinguished by the type of ornamentation and the curvature of cracks.(4)The microspores of S.hainanensis have a unique mesh pattern,suggesting that it has a unique evolutionary pathway.(5)The stomata characteristics and the knob-like bulging characteristics of the leaf epidermis of Selaginella,the color and the ornamentation of microspores are related to the elevation and the moisture of habitat,but the mechanism needs further study.