两种生境下的8种藓类植物茎结构的比较解剖学研究

对极端生境(旱生与水生)下的8种藓类植物,旱生条件下生长的虎尾藓(H edw ig ia cilia ta(H edw.)P.B eauv.)、欧黑藓东亚变种(And reaea rup estrisH edw.var.f auriei(B esch)T akak i)、长蒴紫萼藓(G rimm ia m acrothe-ca M itt.)、日本蓑藓(M acrom itrium jap on icum D oz.et M o lk)和簇生砂藓(R acom itrium aqua ticum(Schrad.)B rid.),水生条件下生长的大叶凤尾藓(F issid ens g rand if rons B rid.)、鳞叶水藓(F ontina lis squam osa H edw.)和短尖美喙藓(E urhynch ium angustirete(B roth.)T.K op.)进行了茎的横切及离析后细胞形态学的比较研究.结果表明:(1)生长在干旱条件下的5种藓类植物的茎无中轴分化,细胞壁厚;离析后可见细胞端尾和纹孔场数目多,端尾数目增多扩大了细胞间的接触表面积,纹孔场数目最多为2.60/细胞,显示出其机械组织发达,这些是对旱生生长环境的适应.(2)生长在水生条件下的3种藓类植物茎的中轴有或无,细胞壁薄;离析后可见细胞端尾和纹孔场数目少,纹孔场数目最少为0.37/细胞,茎表皮细胞壁薄且茎内有大量薄壁细胞,表明其机械组织不发达,这些特征与水生生长环境相适应.本文还对8种藓类植物茎的结构特征在分类中的应用进行了探讨,认为茎表皮、内外皮部宽度及细胞分化的比例、中轴的有或无等在属间种内的性状是稳定的,具分类学意义.

Comparison of Stem Structures of Eight Mosses in Two Habitats

The stems of eights mosses growing in extreme habits(xeric and hydric habitats),Hedwigia ciliata(Hedw.) P.Beauv.,Andreaea rupestris Hedw.var.fauriei(Besch) Takaki,Grimmia macrotheca Mitt.,Macromitrium japonicum Doz.et Molk and Racomitrium aquaticum(Schrqad.) growing in xeric habitats and Fissidens grandifrons Brid.and Fontinalis squamosa Hedw.and Eurhynchium angustirete(Broth) T.Kop.growing in hydric habitats were transected and then the cells of the stems were separated and comparatively examined in their morphology.The results showed:(1) the five mosses growing in xeric habitats presented no main axis differentiations and thick cell walls in their stems;they presented large numbers of tail-ends and pit fields in their stem cells after separation of their stem cells;the large numbers of end tails enlarged intercellular contact area and the highest number of pit field was 2.60 per cell,which indicated that they hadstrong mechanical tissues;and all these corresponded to xeric environments.(2) The three mosses growing in hydric habitats had main axes or no main axes,and thin cell wall in their stems;they presented small numbers of tail ends and pit fields in their stem cells after the separation of their stem cells;the lowest number of pit fields was 0.37 per cell,the epidemic cells of the stems had thin wall and the stems contained a large number of parenchyma cells,which indicated that they had weak mechanical tissues;these feature corresponded to hydric environments.The paper explores the use of the structural features of the stems of the eight mosses in taxonomy,holding that the widths of stem epidermis and outer and inner cortexes,the percentage of differentiated cells and the existence or inexistence of main stem axes vary stably among the genera and in the species,thereby having taxonomic significance.