羊草种群密度与生长动态研究

 通过人为控制种群密度的栽培实验，从基株和构件水平上观察羊草无性系种群的生长动态，分析不同密度水平上羊草种群通过调节种群的生长、发育、增殖以及死亡过程来适应密度制约的途径。研究结果表明：1)羊草种群密度可在不同的构件水平间得到调节。当基株密度得到适当调节后便可减缓构件密度(无性系枝条、根茎芽等)的变化幅度和影响构件的发育进程。2)无性系枝条是羊草种群的主体，常在生长季后期出现大量增长，都处于生长旺盛的幼苗期，为翌年春季的返青积累能量和物质。3)单位面积总生物量随密度增加而提高，虽然尚未出现产量恒值现象，但存活枝条平均单株重(地上生物量)随密度增加呈下降趋势，这已反映出密度制约的作用。4)不同密度下羊草种群的生殖过程表现为：低密度时以无性繁殖为主，根茎芽的存活力较高；高密度时以有性繁殖为主，生殖分配值较大。

Density and Growth Dynamics of Leymus chinensis Population

The influence of Leymus chinensis population density on growth dynamics at modular level was investigated. The correlation between density and growth dynamics of single experimental L. chinensis was analyzed. The results were as follows:① Genet’s density influenced ramet’s density and developmental process. Adjusting genet population density can narrow the variation range of ramet density. ② The population biomass increased as density increase, but it did not come to a constant value. But the biomass per genet began to decrease as density became bigger. ③ Under low density, vegetative propagation dominated and survival capacity of rhizome buds was high while sexual reproduction dominated and the reproduction allocation value was big under high density.