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10种卷柏属植物茎的解剖学研究及其分类鉴定意义

Anatomical Study of the Stems of the 10 Selaginella Species and Its Taxonomic Significance

  • 摘要: 对湖北省及邻近地区产10种卷柏属(Selaginella)植物茎进行了比较解剖研究。结果表明它们在解剖学方面既存在共性特征,又各有其自身的特征。其共性特征表现在:(1)表皮细胞壁多少增厚。(2)皮层通常具机械组织(纤维、厚壁细胞,通常仅有厚壁细胞)。(3)内皮层以内有大型气室,中柱由多数横桥悬于气室中。(4)中柱鞘由1至数层薄壁细胞环列而成。(5)维管束周韧型。但10种卷柏属植物茎的横切面外侧是否具脊状突起,皮层是否具纤维,皮层外侧是否具厚壁细胞以及厚壁细胞的层数,构成横桥的薄壁细胞的形态、数目,气室及中柱的形态、数目,木质部形态等方面具有种间差异,可作为分类鉴定的重要依据。同时,利用茎的解剖学特征,可辅助解决某些仅靠形态学性状难以解决的分类鉴定问题。根据其相似程度,还可进行部分种间亲缘关系的分析。

     

    Abstract: Using the samples collected from Hubei Province and its neighboring region,the anatomical structures of the stems of 10 Selaginella species were observed under light microscope.The results showed that 10 species share some common anatomical characters:(1) The epidermis cells are more or less increased in thickness of the walls.(2) The cortex usually own mechanical tissue,fiber bundles and thick-walled cells(generally only the later).(3) Inside the endodermis,there generally is a large air chamber,with a stele hanged in its central part by the some cross-bridges.(4) The stele is enclosed by the pericyle ring made up of one or more layers of thin-walled cells.(5) The vascular bundle is amphicribral.However,certain significant anatomical differences exist among the 10 species.Whether several features exist would provide significant basis for classification and identification of the 10 species,including ridged heaves outside the epidermis of the stem,the fiber bundles in the cortex,the thick-walled cells in the outer cortex.The shape and number of the air-chamber,stele,xylem and thin-walled cells forming the cross-bridge also are significant characters for classification.Whatmore,microscopic characteristics can also be used to resolve some difficult problems of taxonomy only based on morphological analysis,and to deduce the relationships among some Selaginella species.

     

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