川西北高寒沙区切断根茎对赖草和沙生苔草克隆生长的影响

为了研究高原亚寒带沙化生境中切断根茎对克隆植物基株扩展能力和分株定居能力的影响，在川西北若尔盖高原沙化区内，对根茎禾草赖草和沙生苔草进行了以切断根茎为处理的野外实验。结果表明，赖草和沙生苔草基株的幼小部分(观测单元)地上枝总长度增量、主根茎长度增量和根茎总长度增量显著减少，而对根茎数增量、主根茎节增量和根茎节总数增量影响不显著；赖草观测单元地上枝数增量显著减少，而对沙生苔草地上枝数增量无影响；赖草地上枝与根茎的相关性质发生逆转。这表明．在高原亚寒带半湿润沙化生境中．克隆整合效应显著促进基株幼小部分地上枝和根茎的伸长生长，但对新生根茎的产生和根茎节分化没有影响；切断根茎处理导致赖草、沙生苔草生殖生长与营养生长间竞争加剧，同时使赖草地上部分与地下部分间竞争加剧；观测单元在缺少与基株(或上级株系)的克隆整合作用时，赖草受到的影响大于沙生苔草。

Effects of severied rhizome on clonal growth of Leymus secalinus and Carex praeclara of alpine desertification grassland in Northwestern Sichuan

Effects of severed rhizome on clonal growth of Leymus secalinus and Carex praeclara was investigated in Nuoergai plateau of Sichuan.The results showed that the increments of total length of shoots,length of main rhizome and total length of rhizomes were reduced by the severed rhizomes in the developing parts (observed plant unit) of Leymus secalinus and Carex praeclara,while no effect was observed in the number of rhizomes,number of main rhizome rhizome and total number of rhizome nodes.Severing rhizome reduced the number of Leymus secalinus shoots,but had no effect on Carex praeclara,and the interrelation of shoots and rhizomes was reversed.It suggested that the length growth of shoots and rhizomes in the developing parts were promoted by the clonal integration,while no effect was observed on the emergence of rhizomes and differentiation of rhizomes nodes.The competition between the reproductive growth and vegetative growth of Leymus secalinus and Carex praeclara increased if the plants were severed and the competition between the aboveground and underground increased as well.The effect of severing off treatment on Leymus secalinus was heavier than that on Carex praeclara when lack of clonal integration with genet.