放牧影响下羊草种群生殖生态学的研究

Effect of grazing on reproduction in Leymus chinensis population.

在种群水平上系统研究了放牧对松嫩草原羊草种群无性繁殖、有性生殖和生物量生殖分配的影响 .结果表明 ,放牧制约了羊草种群无性繁殖和有性生殖的更新途径 ,表现在随放牧强度增加 ,无性繁殖体营养枝密度、根茎芽密度和有性生殖体种子生物量、结实数和生殖枝分化率等指标均显著下降 ,特别是重牧后下降迅速 .随放牧强度增加 ,羊草种群根茎生物量的分配比例显著增加 ,而同化器官、非同化器官和种子生物量分配比例都显著下降 ,极牧阶段几乎没有生殖枝的分化 .

The experiment on the effect of grazing on the asexual and sexual reproduction and biomass allocation in Leymus chinensis population was conducted in Songnen grassland. The results show that animal grazing reduced both asexual and sexual reproductive channels.With the increase of grazing intensity,the densities of asexual shoots and rhizome tillers, seed biomass, numbers of seeds per inflorescence and sexual shoot ratio decreased significantly,especially after heavy grazing.The rates of biomass allocation to rhizome increased significantly with increasing grazing intensity, while the rates of biomass allocation to assimilation, unassimilation organs and seed production decreased remarkably.In the haviest grazing stage,there were almost no sexual shoots.