不同利用方式下贝加尔针茅草原4种主要植物叶片功能性状特征

Leaf Characteristics under Different Utilization Ways of Four Main Plant Species in Stipa baicalensis Grassland in Inner Mongolia

草地不合理的利用方式是造成植被退化的主要原因,掌握不同利用方式对植物叶片功能性状的影响,可为区域草地合理利用提供基础资料。试验以贝加尔针茅草原为研究对象,研究围封、放牧和刈割,3种利用方式下,贝加尔针茅(Stipa baicalensis)、羊草(Leymus chinensis)、羽茅(Achnatherum sibiricum)、扁蓿豆(Melisitus ruthenica),4种植物的比叶面积和叶绿素含量的变化特征与叶片N、P元素和土壤铵态氮、硝态氮、全N、全P、N∶P的相关关系,探讨植物个体水平上叶片功能特性对草地不同利用方式的响应。结果表明放牧显著增加了4种植物的比叶面积和贝加尔针茅、羊草的叶绿素含量(P<0.05)。围封和刈割处理下,4种植物比叶面积和叶绿素含量均无显著差异。贝加尔针茅、羊草比叶面积与叶片N、N∶P呈正相关关系(P<0.05),而羽茅、扁蓿豆的比叶面积与叶片N、P、N∶P均无相关关系,比叶面积和叶绿素含量与土壤因子,除了羽茅和扁蓿豆的比叶面积与土壤硝态氮无显著相关性以外,贝加尔针茅、羊草叶绿素含量和比叶面积,羽茅、扁蓿豆叶绿素含量均与土壤硝态氮呈正相关关系(P<0.05)。4种植物比叶面积和叶绿素均与土壤有机C、全N、全P、铵态氮无相关关系。

The unreasonable utilization of grassland is the main cause of vegetation degradation.Better understanding of the effects of different utilization ways on the characteristics of plant leaves is useful for the rational utilization of the grassland.In this experiment,three ways of utilization,enclosing,grazing and mowing,were designed to investigate the difference of the characteristics of plant leaves under different ways of utilization in Stipa baicalensis grassland.Four plant species,Stipa baicalensis,Leymus chinensis,Achnatherum sibiricum,Melissitus ruthenica,were chosen to be determined the specific leaf area and content of chlorophyll,and to be analyzed the correlation of their changes with the elements N and P of the leaves,and soil ammonium nitrogen,nitrate nitrogen,total N,total P,N/P,hence to understand the morphological and physiological responses of leaf to different way of utilization of grassland.The results showed that the specific leaf area of four plant species as well as chlorophyll content of S.baicalensis and L.chinensis was significantly increased in the utilization way of grazing(P<0.05),however,there were no significant difference in specific leaf area and chlorophyll content between before and after enclosing and mowing.The specific leaf area of S.baicalensis and L.chinensis was positively correlated with N content and N/P(P<0.05)in leaf,but there was no correlation of them for A.sibiricum、M.ruthenica.The analysis of the correlation between the specific leaf area and chlorophyll content with soil factors revealed that specific leaf area,the chlorophyll content of S.baicalensis and L.chinensis and the chlorophyll content of A.sibiricum、M.ruthenica were positively correlated with soil nitrate nitrogen respectively(P<0.05),while the specific leaf area of A.sibiricum、M.ruthenica was no significant correlated with the soil nitrate nitrogen.Also,analysis found that the specific leaf area and chlorophyll of the four plant species were not correlated with the soil organic C,total N,total P and ammonium nitrogen.