克氏针茅功能性状对放牧强度的响应及其异速生长分析

The Response of Stipa krylovii Functional Traits to Different Grazing Intensities and Allometric Growth Analysis

以典型草原优势种克氏针茅为研究对象,通过对比地上、地下功能性状和各构件生物量,解析茎、叶、根对长期不同放牧强度的响应。结果表明:(1)在放牧强度GI510下克氏针茅植株茎、叶功能性状变化显著,具体表现为株高变矮、叶片数变少、分蘖数变少、叶片变短变窄,植株基部茎粗与叶片厚度显著减小;(2)克氏针茅根系形态参数随放牧强度增加先增大后减小,在中度放牧GI340下克氏针茅的根系长度、表面积和体积均最大;(3)克氏针茅叶、茎、根系各个生物量及总生物量在重度放牧GI510下最低,比根长和茎叶比最高;(4)在不同放牧强度下克氏针茅株高-根长之间具有显著的异速生长关系,叶-茎生物量、地上-地下生物量之间在中度放牧GI340下表现为异速生长关系。

The response of stem,leaf and root to long-term grazing intensity was analyzed by comparing the aboveground and underground functional traits and biomass of each part in Stipa krylovii,a dominant species of grassland.The results showed that the functional traits of stem and leaf of S.krylovii changed significantly under heavy grazing conditions(GI510),including lower plant height,less leaf and tiller number,shorter and narrower leaf,and decreased stem diameter and leaf thickness at the base of the plant.The root morphological parameters of S.krylovii firstly increased and subsequently decreased with the increase of grazing intensity.The maximum length,surface area,and volume of root were observed under moderate grazing intensity(GI340).The respective and total biomass of leaves,stems,roots of S.krylovii were the lowest under heavy grazing conditions(GI510),but the specific root length and the stem-leaf ratio were the highest.Under different grazing intensities,there was a significant allometric growth relationship between plant height and root length of S.krylovii.The leaf-stem biomass and above-underground biomass showed allometric growth relationship under moderate grazing intensity(GI340).