松嫩草地羊草克隆构型特征在不同种群密度下的可塑性

对不同密度羊草(Leymuschinensis)种群的克隆构型特征进行了调查,比较在资源水平相对一致时,羊草克隆构型特征,如根茎节间长度、间隔子长度、分枝距离和分枝角度,对种群密度变化的可塑性.结果表明:随着种群密度增加,羊草根茎节间长度和间隔子长度逐渐减小,分枝角度增大,且分枝角度在不同密度间差异显著.分枝角度的频率分布格局在不同密度间也存在显著差异,种群密度高时,羊草根茎具有更多的大分枝角.此外,羊草根茎节间长度、间隔子长度和分枝角度与其种群密度具有较强的冥函数关系.羊草根茎克隆特征在不同密度间具有较强的可塑性,当种群密度低时,羊草克隆特征更趋于“游击型”;随着种群密度的增加,其“游击型”特征减弱. 图2表2参19

CLONAL PLASTICITY IN RESPONSE TO POPULATION DENSITIES OF LEYMUS CHINENSIS IN THE SONGNEN GRASSLAND

Comparisons of clonal architecture of Leymus chinense , in a population density gradient changing from low to high density in the Songnen Grassland, were conducted. The main clonal architecture, including internode length, space length, interbranching length and interbranching angle, was analyzed comparatively. Furthermore, clonal plasticity of L. chinense in response to its change in population densities was also discussed. The results showed that in the relatively homogeneous habitat, the internode length and space length of L. chinense decreased along with the increase of population density, but the interbranching angle increased. In addition, no significant difference existed in clonel characteristics among different population densities, beside interbranching angle and their frequent distribution. Comparatively, there were more big interbranching angles in high population density than in low density. At the same time, observable power function relations existed between population density and internode length, space length and interbranching angle. Clonal architecture of L. chinense tended more to "guerilla" in low density, and the trend would be weakening in high density. Therefore, clonal plasticity of L. chinense in response to its population density was found relatively obvious. Fig 2, Tab 2, Ref 19