Fe、Mn、Cu在锡林河流域温带草原植被中的含量特征

The content characteristics on Fe, Mn and Cu in the grassland vegetation of Xilin River Basin

本文研究了Fe、Mn、Cu三个同周期的植物营养元素在内蒙古锡林河流域三个主要草原群落植被中的含量特征,研究表明:三个元素在凋落物及根系中的含量较高,在立枯中较低,在活体中最低;沿降水、气温和海拔梯度,活体、凋落物中的含量按贝加尔针茅草原、羊草草原、大针茅草原递减,Cu例外,在植物生长末期是递增的;立枯中的元素含量在生长初期递增,在后期递减,Cu也例外,初期和后期都是递增的;在植物系统各组成部分中,生长初期三个元素的含量要高于生长后期;地上部植物体分解程度越高,三个元素的含量也越高;Cu强烈富集于根系中;土壤及降水分别是影响植物元素含量及植物分解的重要因子;三个元素在各草原群落地上部活体中的含量都能够满足牲畜的需要。

Fe, Mn and Cu, as elements of the fourth period in the periodic table of elements, are all essential elements for plants and animals in grassland ecosystems. The contents of Fe, Mn and Cu in parts of the grassland vegetation , such as shoots, standing dead, litters and roots, were measured in the initial stage of plant growth and the later stage of plant growth, respectively. The results showed that the contents of Fe, Mn and Cu in shoots were suitable for plant and livestock, and the nutritive value of the Stipa baicalensis grassland community, which belongs to meadow steppe, is higher than those of the Leymus chinensis and Stipa grandis grassland communities, which belong to typical steppe, in point of essential elements Fe, Mn and Cu.Regularities of Fe, Mn and Cu content distribution in shoots, standing dead, litters and roots are as follows: From litters and roots, standing dead, to shoots, their contents gradually decreased; along the precipitation, air temperature and altitude gradient, the contents of Fe and Mn in shoots and litters gradually decreased from Stipa baicalensis grassland community, Leymus chinensis grassland community to Stipa grandis grassland community, and Cu gradually increased in the initial stage of plant growth and decreased in the later stage of plant growth as the same order. The contents of Fe and Mn in standing dead gradually increased in the initial stage and decreased in the later stage, and the contents of Cu gradually increased in the initial stage and the later stage. The contents of the three elements in every part of plant ecosystems were higher in the initial stage of plant growth than the later stage. The more intensely the dead plants aboveground were decomposed, the higher the contents of Fe, Mn and Cu were. Cu is very abundant in roots.