三峡水库消落带几种草本植物根系的垂直分布特征

目的]明确三峡水库消落带典型草本植物根系分布特征,为三峡消落带的植被恢复提供依据。方法]在三峡腹地石宝镇消落带选取牛鞭草(Hemarthria altissima)、扁穗牛鞭草(Hemarthria compressa)、双穗雀稗(Paspalum paspaeoides)三种人工恢复草本和自然恢复草本,利用WinRhizo Pro.2009c根系分析系统研究其根系的土壤剖面分布特征。结果]4种草本类型的的根系主要分布在0—10cm土层,根长密度、根直径(除自然杂草外)、根表面积密度、根体积密度和根尖密度均随土壤深度的增加而呈指数函数减小;除根径外,在整个土层剖面中(0—25cm),3种人工草本的根系指标都要显著高于自然恢复杂草。结论]4种草本根系发达,对消落带水淹胁迫的适应性强。

Root Distribution of Several Herbaceous Plants in Water Level Fluctuating Zone of Three Gorges Reservoir

Objective] Understanding the root distribution characteristics of artificial and natural restoration herbaceous plants are important to provide evidences for artificial revegetation in the Three Gorges riparian zone.Methods] Three artificial herbs, including Hemarthria altissima, Hemarthria compressa, Paspalum paspaeoides, and one local natural herb from the riparian zone of Three Gorges Reservoir were selected to investigate their root characteristics using root analysis systems(WinRhizo Pro. 2009c). Their root distributions in soil profiles were compared.Results] The results showed that roots mainly distributed in 0-10 cm soil. Root length density, root diameter(except for natural recovery grass), root surface area density, root bulk density and root tips density decreased exponentially with soil depth. Generally, throughout the investigated soil profiles(0-25 cm), root features of three artificial restoration herbs were considerably higher than that of the local natural grass.Conclusion] The four investigated herbs have well-developed roots and adapted well to the habitat of long submerged stress.