青藏高原东缘匍匐茎草本野草莓的分株种群特征及其沿海拔梯度的变化

对青藏高原东缘 5个不同海拔高度 ( 2 4 2 6m、2 75 0 m、32 0 0 m、3484m和 3944m)上旷地和林下遮荫条件下匍匐茎草本野草莓的分株种群特征进行了研究。结果显示 :无论在旷地或林下遮荫条件下 ,野草莓分株种群的密度随海拔升高显著减小 ,旷地条件下野草莓分株种群密度显著高于遮荫条件下的分株种群密度。不同海拔高度上 ,野草莓分株种群密度在不同光照条件下的变化存在显著差异。旷地条件下 ,随海拔升高其根冠比呈二次曲线变化。林下遮荫条件下 ,海拔 2 4 2 6m处的根冠比最低。光照条件的变化对野草莓分株种群的根冠比没有显著影响。运用空间自相关分析法 ( Moran` I)研究和 3944m处野草莓分株种群的空间分布格局 ,结果显示野草莓分株种群在多个尺度上呈现非随机分布格局 ,其中研究了海拔 348m处 d=1( 0 .2 m)尺度的集聚分布格局频率最高 ;与海拔 3484m相比 ,3944m处野草莓分株种群的集聚尺度更大。最后 ,结合克隆植物对环境的生态适应意义进行了讨论。

The characteristics of stoloniferous herb Fragaria vesca L. ramet population and their variation along an altitudinal gradient in the eastern edge of the Qing-Zang Plateau in China

Stoloniferous herb Fragaria vesca was sampled in the unshading (open fields) and the shading conditions (forest undergrowth) at the five different altitudes (2426m, 2750m, 3200m, 3484m and 3944m) in the eastern edge of Qing-Zang Platea u in China in order to investigate the characteristics of its ramet population a nd their variation along the altitudinal gradient. The resul ts show that its ramet population density decreased with increase of altitude, b oth under the unshading and the shading conditions. Under unshading conditions, its ramet population density was significantly higher than that under shading co nditions. The interaction of elevation by light was significant with respect to ramet population density. Under unshading conditions, its ratio of root to shoo t varied quadratically with increase of elevation. Under shading conditions, its ratio of root to shoot was smallest at 2426m above sea level than those at the other four altitudes. There was not significant effect of the light condition on the ratio of root to shoot. The distribution pattern of Fragaria vesca rame t po pulation at 3484m above sea level and 3944m above sea level was investigated by using spatial auto-correlation analysis (Moran`I). The results show that the ra met population of Fragaria vesca had non-random distribution pattern at mul tipl e scales and the most frequently observed pattern was contagious at the scale of d=1(0.2m). The maximum size of ramet cluster was bigger at 3944m above sea level than that at 3484m above sea level. Finally, the results were discussed i n the context of adaptation of clonal plants to environments.