不同放牧管理模式下高寒草甸共有优势种叶片功能性状比较

Comparison of leaf functional traits of commondominant species in alpine meadow underdifferent grazing management modes

摘要:

比较高寒草甸连续放牧(CG)、传统放牧(TG)、生长季休牧(GSG)和禁牧(PG)不同放牧管理模式下4种共有优势种垂穗披碱草(Elymus nutans)、矮嵩草(Kobresia humilis)、扁蓿豆(Medicago ruthenica)和鹅绒委陵菜(Potentilla anserina)的叶长、叶宽、叶周长、叶面积及比叶面积(SLA)的差异,旨在为高寒草甸的放牧管理提供参考。结果发现:1)垂穗披碱草叶长、叶周长及叶面积的大小次序为:GSG＞PG＞TG＞CG,SLA表现为:CG＞PG＞TG＞GSG;与CG管理模式相比,GSG、TG和PG的矮嵩草叶面积分别减小了40.13%、56.06%和61.83%,SLA依次为:TG＞GSG＞TG＞CG;鹅绒委陵菜叶长、叶周长和叶面积,扁蓿豆的叶周长、叶面积及SLA均表现为:GSG＞PG＞TG＞CG;2)叶片性状的变异系数显示,垂穗披碱草的叶宽和SLA,矮嵩草叶面积具有较强的可塑性,扁蓿豆SLA和叶宽可塑性较强,鹅绒委陵菜的SLA、叶面积可塑性最强;3)Pearson相关分析表明,放牧管理下的土壤紧实度与有机质显著影响了叶片功能性状。物种间综合比较发现,鹅绒委陵菜叶片功能性状的可塑性是适应退化高寒草甸的一个重要因素。

Abstract:

This study selected four common dominant species including Elymus nutans,Kobresia humilis,Medicago ruthenica and Potentilla anserina under four different modes of grazing management,i.e.,traditional continuous grazing(CG),alpine meadow grazing(TG),growing season grazing given(GSG) and grazing prohibition(PG).Leaf characteristics including leaf length,leaf width,leaf perimeter,leaf area and specific leaf area(SLA) were analyzed.The aim was to provide reference for grazing management of alpine meadow.The results showed that the leaf length,leaf circumference and leaf area of E.nutans followed the order of GSG＞PG＞TG＞CG,the SLA performance as the order of CG＞PG＞TG＞GSG.Compared with the CG management model,the leaf area of K.humilis of GSG,TG and PG reduced by 40.13%,56.06% and 61.83%,respectively,while its SLA followed the order of TG＞GSG＞TG＞CG.Leaf length,leaf perimeter and leaf area of P.anserina,together with leaf perimeter,leaf area and SLA of M.ruthenica showed an order of GSG＞P G＞TG＞CG.The variation coefficient of leaf traits showed that E.nutans had stronger plasticity in leaf width and SLA;K.humilis had stronger plasticity in leaf area;M.ruthenica had stronger plasticity in leaf width;while P.anserine had the strongest plasticity in SLA and leaf area.Pearson correlation analysis showed that soil compactness and soil organic matter significantly affected leaf functional traits under grazing management.The comprehensive comparison among species showed that the plasticity in leaf functional traits was an important factor for the adaptation of plants to degraded alpine meadows.