摘要
本文研究了青藏高原高寒草甸区3个不同退化程度的草地群落结构和退化生境常见物种矮火绒草在退化草地中优势度、繁殖分配、叶表型功能性状差异。结果表明:随着退化程度加剧,土壤砾石含量、温度显著升高,土壤含水率、植物群落高度和密度显著降低(P<0.05);矮火绒草生殖株高响应不明显(P>0.05),营养株高呈先升高后降低趋势(P<0.05),生殖株的繁殖分配显著增加(P<0.05);矮火绒草单叶质量、单叶面积、比叶面积在各退化草地群落中差异不明显(P>0.05),叶厚度和叶体积显著降低(P<0.05),叶组织密度和叶长宽比升高。在退化梯度上,矮火绒草叶组织密度、叶厚度等功能性状的响应敏感性强于比叶面积。通过权衡叶表型功能性状(增加叶组织密度、降低叶厚度等)对退化生境进行反馈可以保证资源获取,并且采取增加繁殖分配的生殖策略提高物种的竞争力和保证繁衍。
This study was conducted for exploring the grassland community structure,floristic assembly mechanism and the dominance,reproductive allocation,and leaf phenotypic functional traits of Leontopodium nanum in 3 different degraded lands of alpine area of Qinghai-tibetan Plateau.The results showed with the increasing degradation level,the gravel mass ratio and the temperature increased greatly,whereas the soil water content,the community height and density decreased greatly(P<0.05); the response of plant height,leaf mass,leaf area and specific leaf area(SLA) of Leontopodium nanum showed little variance(P>0.05),whereas,the reproductive allocation increased significantly,the leaf thickness and volume decreased significantly(P<0.05),the leaf tissue density and length-width ratio increased.In terms of degradation gradient,the response sensibility of the leaf tissue density and the thickness were stronger than that of the SLA.For degradated vegetation,a trade-off among different leaf phenotypic functional traits could ensure resources access,and the strategy of enhanced reproductive allocation could improve species' competitiveness and increase their reproductive ability.
引文
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