切断根茎对根茎禾草沙鞭和赖草克隆生长的影响

为了研究半干旱内陆沙化生境中植物克隆整合对克隆植物基株扩展能力和对克隆植物分株定居逆境能力的贡献，在内蒙古鄂尔多斯高原毛乌素沙地对根茎禾草沙鞭（Rsammochloavillosa（Trin．）Bor）和赖草（Leymussecali－nus（Georgi．）Tzvel．）进行了以切断根茎为处理的野外实验。实验结果表明，切断根茎处理使根茎禾草沙鞭基株的幼小部分（观测单元）在实验期间根茎数量增量、地上技数量增量、地上枝总长度增量、主根茎节数增量、根茎节总数增量、主根茎长度增量和根茎总长度增量显著地减少。然而，切断根茎处理对另一根茎禾草赖草基株幼小部分（观测单元）的上述7个特征在实验期间的增量没有影响。这些结果指示着在克隆整合及其对克隆生长贡献方面的种间差异。沙鞭的克隆整合特性和克隆生长特性对它在水分短缺、蒸散剧烈、养分贫瘠、生境斑块化和扰动经常的沙化草地环境中的生存能力有重要贡献。

Effects of Severing Rhizome on Clonal Growth in Rhizomatoua Grass Species Psammochloa villosa and Leymus secalinus

A field experiment was conducted in Inner Mongolian dune to investigate the contribution of clonalintegration to genet expansion and ramet establishment in clonal plants in semi-arid inland dune. In the experiment, the developing parts (plant observing unit) of two thizomatous grass species Psammochloa villosa(Trin.) Bor and Leymus secalinus (Ceorgi.) Tzvel. were subjected to the treatment of severing rhizomes. The7 characters relevant to the clonal growth of the plant observing units were investigated such as total length ofshoots, number of shoots, number of rhizomes, length of main thizome, total length of thizomes, number ofmain rhizome nodes and total number of rhizome nodes. The results showed that the increments in those plantchumers were reduced by the treatment in P. villosa, while no effect of the treatment was observed in L.secalinus. The results suggest an interspecific difference in clonal integration and in its contribution to clonalgrowth. In P. villosa, clonal integration and clonal growth offer peat contributions to the survival of theplants in the sandy grassland characterized where water shortage, strong transevaporation, infertility, habitatpatchiness and frequent disturbance were most characteristic.