基于不同方法的毛茛族(毛茛科)导管穿孔板比较研究

Comparative investigation of vessel perforation plates of Ranunculeae(Ranunculaceae)based on different methods

关键词:  毛茛族, 毛茛科, 导管, 穿孔板

Key words:  Ranunculeae, Ranunculaceae, vessel elements, perforation plates

摘要:

导管分子的演化与植物的进化相关联。毛茛科是联系基部被子植物和核心真双子叶植物的关键类群,对其导管穿孔板的研究具有重要的系统学意义。为研究毛茛科毛茛族不同属植物导管穿孔板类型及其与环境的相关性,该文利用新的扫描电子显微镜和半薄切片技术,对该族7属8种植物次生木质部导管状分子进行了比较观察。结果表明:木质部管状分子以单穿孔板为主,除了茴茴蒜、鸦跖花和角果毛茛外,其他类群均具有梯状穿孔板; 侧金盏花属的蜀侧金盏花导管分子穿孔板的类型多样,有单穿孔板、梯形穿孔板、买麻藤式穿孔板、网状穿孔板和梯-网混合型穿孔板; 碱毛茛属的圆叶碱毛茛具单穿孔板、梯形穿孔板和网状穿孔板; 在水毛茛属水毛茛的根和茎中未离析出导管,半薄切片显示其具原始的环纹导管。对不同类型导管纹孔膜进行了观察,发现有对列纹孔、互列纹孔,纹孔膜完整或有残余。毛茛族植物导管长度的多样性较高。该文还对不同导管类型的适应性意义和毛茛族的系统位置进行了探讨,揭示了导管分子微形态结构特征与其所处的环境存在一定的适应性。太白美花草、蜀侧金盏花、鸦跖花的导管类型与高寒环境相关,角果毛茛、水毛茛的导管类型分别与其旱生、水生环境相关。

Abstract:

The evolution of different kinds of vessel molecules is always related to plant evolution. Ranunculaceae(Ranunculales)is a key family which links the basal angiosperm and the core-eudicots in the angiosperm phylogeny group system. Studies on the vessel perforation plates of this important family have great systematic significance, but few studies have been addressed till now. Here, the vessel elements and their perforation plates in the secondary xylem of Ranunculeae, including seven genera and eight species, were observed with the scanning electron microscope and the semithin section, in order to know the relationship betweenthe vessel with their environments in different species in Ranunculaceae of Ranunculeae. The results were as follows: Simple perforation plates were found in seven species, except for the Batrachium bungei; Scalariform perforation plates were found in four species, i.e. Callianthemum taipaicum, Adonis sutchuenensis, Ranunculus sceleratus and Halerpestes cymbalaria, but not for Ranunculus chinensis, Oxygraphis glacialis and Ceratocephalus orthoceras; Perforation plates of vessel elements of Adonis sutchuenensis were diverse, including simple perforation plate, scalariform perforation plate, reticulate perforation plate, gnetum type perforation plate, and scalariform-reticulate perforation plate; Simple perforation plate, scalariform perforation plate, and reticulate perforation plate were found in Halerpestes cymbalaria. In this study, we did not found vessel elements by dissociation the root and stem of Batrachium bungei. On the contrary, we found that there were annular vessels by semithin section. We also found that the side walls, and the pit membranes were unbroken or residual. The length diversities of those vessel elements of Ranunculeae were very high. There were significant differences in the average length of vessel elements in different species of Ranunculeae. At the same time, the differences were conspicious among different types of vessel elements even in the same species. We also discussed the adaptive significance of different types of vessel elements and the systematic position of Ranunculeae in the family Ranuculaceae. The results indicate that micro-structures of the vessel elements are also adapted to their growing environments. The vessel elements of Callianthemum taipaicum, Adonis sutchuenensis and Oxygraphis glacialis were related to their cold environments and those of Ceratocephalus orthoceras and Batrachium bungei were related to xerophytic and aquatic environment, respectively.