不同生态条件下羊草无性系种群分蘖植株年龄结构的比较研究

在４次取样的平均年龄谱中，１龄级分蘖植株的数量比重是割草样地＞休闲样地＞放牧样地，２、３、４龄级分蘖植株均为放牧样地＞休闲样地＞割草样地。放牧干扰可以促进各龄分蘖节的再生存活。但是对根茎形成分蘖植株却起到了一定的削弱作用。割草干扰可以促进翌年根茎形成分蘖植株，从而使各龄级分蘖节的再生存活量减少。放牧能促进老龄分蘖植株的物质生产。割草将影响翌年生长季前期各龄分蘖植株、尤其是老龄分蘖植株的物质生产，但是这种影响至生长季中期便消失。休闲可促进各龄分蘖植株、尤其是老龄分蘖植株在翌年生长季前期的物质生产。各样地营养分蘖植株和生殖分蘖植株的生物量均以１龄分蘖植株最大，并且随着年龄的增加而减少。割草地羊草种群在乳熟期的生殖分配是３龄＞１龄＞２龄级分蘖植株。从潜在种群芽的年龄结构看，翌年割草地将仍是增长型种群，放牧地和休闲地将是稳定型种群。

西辽河平原不同利用条件下羊草无性系种群结构的研究

According to the field investigation in the natural grassland of the Xiliao River Plains,the tillers belonged to four or three age classes,and the rhizomes belonged to four age classes under different disturbance habitats. The numbers of the potential populations composed of winterness seedlings and buds were dominant in the first age class. Winterness seedlings belonged to three age classes, while buds belonged to four age classes under all disturbance habitats. The age structure of the potential populations showed an expanding age structure.