宁夏荒漠草原蒙古冰草资源分配特征

为了解不同群落生境蒙古冰草(Agropyron mongolicum)资源权衡策略及种群维持机制，在宁夏荒漠草原选取以蒙古冰草为优势种或亚优势种的群落为研究对象，研究了不同群落蒙古冰草资源分配特征。结果表明：(1)蒙古冰草个体生物量及根冠比在不同群落之间差异显著(P<0.05),构件生物量分配均表现为根>茎>叶>穗；(2)不同群落蒙古冰草各构件C,N,P含量均以根部最低，C/N,C/P以茎部最高，N/P以叶部为高，比值范围为18～23;不同群落之间则表现为C/N和C/P总体以M2群落较高，地上部各构件N/P以M3群落较高(P<0.05);(3)蒙古冰草地下生物量与土壤含水量呈显著负相关，与各构件N,P元素含量呈显著正相关；各构件P元素含量与其生物量分配比及地上地下生物量之间存在显著相关关系(P<0.05)。综上，蒙古冰草可通过调整自身构件分配格局和养分利用策略保证其在不同群落生境的生长发育和繁殖。

Resource Allocation Characteristics of Agropyron mongolicum in the Desert Steppe in Ningxia

In order to understand the resource tradeoff strategy and population maintenance mechanism of Agropyron mongolicum in different community habitats,the desert steppe communities with Agropyron mongolicum as the dominant species or subdominant species in Ningxia were selected as the research objects,and the resource allocation characteristics of Agropyron mongolicum in different communities were analyzed. The results showed below:(1) the individual biomass and root-shoot ratios of Agropyron mongolicum varies significantly among different communities (P<0.05),the biomass allocation to the components was following the order:root > stem > leaf > panicle;(2) the contents of C,N and P were the lowest in its roots comparing to its other components of Agropyron mongolicum in all communities. The C/N and C/P ratios were the highest in stems,and N/P ration was the highest in leaves with a value of 18~23. Among different communities,the C/N and C/P rations of the plant were highest in the Stipa breviflora + Agropyron mongolicum community generally,and N/P of aboveground components was higher in M3 community (P<0.05). (3) The correlation analysis showed that the belowground biomass of Agropyron mongolicum was negatively correlated with soil water content,but positively correlated with N and P contents of its all components. The P content of individual component of that plant was significantly correlated with its biomass proportion. In conclusion,Agropyron mongolicum could adjust the resource allocation pattern to its components and the nutrient utilization strategy to support its growth,development and reproduction in different community habitats.