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薹草属少花薹草组(莎草科)小坚果形态和微形态及其分类学意义

Nutlet Morphology and Micromorphology of Carex sect. Paniceae(Cyperaceae) and Its Taxonomic Significance

  • 摘要: 利用扫描电镜对少花薹草组(Carex sect. Paniceae)27种及4变种(东亚14种4变种,北美13种)小坚果形态与微形态特征进行比较观察。结果表明(:1)所有材料小坚果的形状为倒卵球形和钝三棱状,组内很一致,长度为1.53~3.59 mm,同种不同居群个体差异不显著(P>0.05)。(2)表皮细胞一般为五至七边形,偶有四边形或八边形,丝柄薹草(C. rouyana)不同个体间有变异;垂周璧式样直或微波状;硅质台平,偶有凹或略凸,具1个中心体,C. filipes var. kuzakaiensis和C. filipes var. tremula中偶见2个中心体,无卫星体,这些性状种内稳定。(3)利用表皮细胞形状、硅质台凹凸情况和中心体个数对于区分近似种具有价值,如白马薹草(C. baimaensis)和线柄薹草(C. filipes),且可以区分一些种下等级,如线柄薹草及其变种var. kuzakaiensis、var. oligostachys和var. tremula。(4)sect. Paniceae s.s.和sect. Laxiflorae小坚果形态和微形态上具有较高一致性,具有重要分类学意义。

     

    Abstract: Nutlet morphology and micromorphology of 27 species with four varieties of Carex sect. Paniceae were observed under scanning electron microscopy(SEM).The results showed that:(1)The nutlet shape of all samples(beak excluded)were obovoid trigonous,with the length ranged from 1.53-3.59 mm.The nutlet length between different populations of the same species revealed stability and no significant difference exist by statistical analysis.(2)The epidermal cells were five to seven gonal,rarely four or eight,which was various within the different individuals of C. rouyana.The anticlinal wall was straight or microwave,and silica platform was flat,occasionally concave or slightly convex,with solitary central silica body but without satellite body.Whereas each epidermal cell of C. filipes var.kuzakaiensis and C. filipes var. tremula occasionally had two central silica bodies.(3)Based on the shape of epidermal cells,numbers of central silica platform,some species were distinguished from similar species,such as C. baimaensis and C. filipes,and it was also valuable to distinguish the varieties of C. filipes,ie. var. kuzakaiensis,var.oligostachys and var. tremula.(4)Sections Paniceae s.s. and Laxiflorae had a high consistency in the morphology and micromorphology of nutlets.It indicated that the morphology and micromorphology of nutlets were of great importance of taxonomic significance.

     

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