高寒矮嵩草草甸4种主要植物补偿生长变化与耐牧性比较研究

Compensatory Growth and Grazing-tolerance of 4 Major Plant Species in Alpine Kobresia humilis Meadow

为了探讨高寒矮嵩草草甸4种主要植物的补偿生长机制和耐牧性差异。通过裂区区组设计的方法进行刈割(留茬1、3cm及不刈割对照)、施肥(施尿素和磷酸二胺、不施)和浇水(浇、不浇)控制实验,调查研究了垂穗披碱草(Elymus nutans)、异针茅(Stipa aliena)、矮嵩草(Kobresi a humilis)和粗喙薹草(Carex scabrirostris)分株密度、株高和分株地上生物量及其相对生长率的变化。研究结果表明:2种禾本科植物垂穗披碱草和异针茅的补偿高度和地上补偿生物量对刈割的响应更加敏感;刈割后异针茅、矮嵩草和粗喙薹草的分株密度发生超补偿,4种植物的株高相对生长率都显著增加,地上生物量相对生长率在种间存在较大差异。4种植物的耐牧性大小顺序为矮嵩草>粗喙薹草>垂穗披碱草>异针茅。施肥能显著提高4种植物的补偿高度、地上补偿生物量、株高相对生长率和耐牧性,说明在具有明显的土壤养分限制作用的高寒草甸群落中,植物的耐牧性依赖于土壤速效养分的可获得性。

In order to reveal the compensatory mechanism and grazing-tolerance ability of the 4 species plants at the Haibei Research Station of the Chinese Academy of Sciences. The experiment used a split-pot design with clipping treatment on the whole plot （stubbled 1 cm, 3 cm and unclipped control） and both fertilizer （fertilized and unfertilized Urea ＋ DAP） and water （watered and unwatered） treatments in subplots. Our objectives were to examine how the compensatory growth of Elymus nutans, Stipa aliena, Kobresia humilis and Carex scabrirostris （including compensatory height, ramet density, compensatory abovegroud biomass per ramet and relative growth rate （RGR） varies with different levels of clipping, fertilizing and watering. The results showed that the responses of compensatory height and compensatory abovegroud biomass to clipping were more sensitive for the two Gramineous plants than the two Cyperaceae plants. Ranaet density of S. aliena, K. humilis and C. scabrirostris were appeared overcompensatory after defoliation damage. RGR of ramet height of the 4 species were increased by clipping treatment; RGR of compensatory biomass were different among species. The order of the tolerance ability of they was K. humilis〉C, scabrirostris〉E, nutans〉S, aliena. Fertilizing can induce obvious increasing in compensatory height, compensatory biomass, RGR of ramet height and tolerance to grazing for the 4 species. It was suggested that the grazing-tolerance of the 4 species plants depended on the resource availability in soil in alpine meadow.