松嫩平原赖草无性系生长及其构件的年龄结构

赖草是长根茎型禾草，是典型的无性系植物．在松嫩平原栽培条件下，移植第1年的赖草无性系，经过一个完整生长季的营养繁殖，最多可形成215个分蘖株，在4个取样的无性系中，最大的无性系是最小的5．4倍；经过2个完整生长季最多可形成2852个分蘖株，最大为最小的2．7倍．在无性系整体水平上，2个年度间无性系扩展面积平均增长了13．2倍，分蘖株平均增长了13．3倍，根茎的累积长度平均增长了15．9倍，根茎节数平均增长了11．2倍，根茎生物量平均增长了14．7倍．无性系分蘖株由2个龄级组成，呈增长型年龄结构，并且随着无性系的生长，其增长型年龄结构更为明显．无性系的芽库均由3个龄级组成，亦呈增长型年龄结构，但随着无性系的生长，其增长型年龄结构趋于减缓．赖草无性系以形成大量的根茎顶端芽和根茎节间芽发育成分蘖株，实现无性系空间生态位的扩展和持续更新．

Clone growth and its age structure of Leymus secalimus modules in the Songnen Plain of China

Leymus secalimus,a species of typical clonal plant,is a long-rhizome grass.Under cultivated condition in the Songnen Plain of China,its transplanted single tiller could form 215 tillers at most by vegetative reproduction of a clone in a growth season,and the largest clone was 5.4 times of the smallest one among four sampling clones in the first year.In the second year,the largest clone could form 2852 tillers at most,which was 2.7 times of the smallest one in two growth seasons.At unitary level,the expanding area of the clones and the number of the tillers increased by 13.2 and 13.3 times,respectively,and the accumulative length,nodes number and rhizomes biomass increased by 15.9,11.2 and 14.7 times averagely by the end of the growth season in the second year than in the first year,respectively.The tillers consisted of two age classes and showed expanding age structure,which was more obvious with the growth of clones.The bud banks consisted of three age classes and showed expanding age structure,which decreased gradually with the growth of clones.The tillers could be developed through forming lots of topmost buds and node buds of rhizome,and the clones achieved the spatial niche expansion and repetitive regeneration.