黔中地区不同林龄马尾松群落细根功能性状及其异速生长关系

细根作为植物吸收养分和水分的主要器官，其功能性状对森林生态系统功能具有重要影响。以黔中龙里县林场的马尾松林为对象，测定3个林龄马尾松林(25、37、52 a)群落中马尾松与优势灌木的12个根功能性状，分析随林龄变化根性状的异速生长关系。结果表明，随马尾松林龄增长，马尾松细根性状指标存在显著性变化；其中马尾松根长密度和根表面积密度随林龄增长表现为52 a＞25 a＞37 a的马尾松林；马尾松根生物量密度、根体积密度和根直径随林龄增长呈显著增加趋势，而比根长、比表面积和根组织密度随着林龄增长则呈现下降的变化趋势。不同林龄马尾松林下优势灌木组成结构存在显著差异，同种灌木的根长密度、比根长和比表面积随马尾松林龄变化存在显著性差异变化。马尾松的根生物量密度、根体积密度、比根长、比表面积和根直径随林龄增长存在显著的异速生长关系，这表明马尾松细根随林龄变化对资源获取利用的策略发生着改变；马尾松倾向于以更长的细根长度而不是更大的根表面积获取资源，相较于高林龄林分，低林龄林分马尾松林的马尾松根系有更高的比根长，表现出低投资高收益的生态策略。

Fine Root Functional Traits and Its Allometric Growth Relationship of Pinus massoniana Forests Between Different Stand Ages in Central Guizhou

As the main organ for plants to absorb nutrients and water,fine roots have important effects on the function of forest ecosystem.In this study,Pinus massoniana stands occurring in the Forest Farm of Longli County,located central Guizhou Province,were taken as the research object.Roots of P.massoniana and dominant shrubs were collected from the P.massoniana stands with different stand ages (25-,37-,and 52-year-old).Twelve root functional traits were measured to analyze and the allometric growth relationship between stand age and root functional traits.The results showed that the fine root traits of P.massoniana changed significantly with the increase of stand age,and the increase of root length density and root surface area density with stand age was as follows:52->25->37-year-old stand.The root biomass density,root volume density and root diameter of P.massoniana increased significantly with stand age,while the specific root length,specific surface area and root tissue density decreased with the age.The root length density,specific root length and specific surface area of the dominant shrub had significant differences with the change of stand age.The root biomass density,root volume density,specific root length,specific surface area and root diameter of P.massoniana showed a significant allometric relationship with stand age,which indicated that the strategies of resource acquisition and utilization of fine roots of P.massoniana changed with the change of stand age.In general,P.massoniana tended to acquire resources with longer fine root length rather than larger root surface area,and to accumulate biomass more rapidly in low-age stand than in high-age stand.