晋西黄土高原虎榛子根系分布特征

Root Distribution Characters of Ostryopsis davidiana on Different Sites in the Loess Plateau of Western Shanxi

采用分层分段挖掘法,对晋西黄土高原虎榛子根系的分布特征进行了研究。结果表明,不同立地的虎榛子根系分布特征具有明显差异性;在半阴坡立地上,无论是疏导性根还是吸收性根,垂直分布深度均明显较半阳坡大;半阳坡虎榛子根系较半阴坡的生物量明显减少。土壤水分状况与不同立地灌木根系分布状况相似,这表明虎榛子对不同生境中土壤含水量变化的适应上表现出差异,这种差异更有利于植物根系对坡地土壤水分的吸收。不同坡向上各剖面的根系分布与根系生物量、根长的分布相似,随着距地面垂直距离的增大,根量减少。根桩上坡方向的根系较下坡方向分布较深,各层分布均匀,根量较多,表明不同坡向上大部分根系以水平根或斜生根的形式向根桩上坡方向发展,这种特点反映了根系在特殊立地条件下的生态可塑性。

By means of dig methods from up to down, the root distribution characters of Ostryopsis davidiana were studied in the loess plateau of western Shanxi. The results indicated that there were significant differences in the root distribution characters on different sites. The depth of the vertical distribution of both leading roots and absorbing roots on half shady slope was larger than on half sunny slope. The root biomass on half sunny slope was obviously smaller than that of half shady slope. The distribution of soil moisture content was the same with the root distribution. This result approves that the growth of plants show diversity in different soil moisture contents on different sites. However, this diversity is benefit to roots absorption of soil moisture. Root distribution in different profiles on different slopes showed the same with the distribution of root biomass and root length. As the increase of distance to soil surface, the root quantity decreased. The vertical distribution of root in the upgrade of stake was deeper than that in the downgrade. Distribution in every layer was more even and root quantity was more in the upgrade of stake. These distributions demonstrate that most roots grow to the upgrade of stake in the form of lateral roots and diagonal roots. These characters show that root ecological plasticity in special site.