青藏高原草地植物群落冠层叶片氮磷化学计量学分析  

Canopy leaf N and P stoichiometry in grassland communities of Qinghai-Tibetan Plateau, China

作　　者：杨阔[1,2] 黄建辉[1] 董丹[1,2] 马文红[3,4] 贺金生[4] 

机构地区：[1]中国科学院植物研究所植被与环境变化国家重点实验室,北京100093 [2]中国科学院研究生院,北京100049 [3]内蒙古大学生命科学学院,呼和浩特010021 [4]北京大学城市与环境学院生态学系,北京100871

出　　处：《植物生态学报》2010年第1期17-22,共6页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(30870381和30670322)资助项目

摘　　要：叶片氮(N)和磷(P)的化学计量学研究涉及到植物生态学的众多领域与多个尺度,然而各个尺度上的化学计量学研究并未同步展开。通过对青藏高原47个草地样地连续3年的调查,分析了当地群落水平上的植物叶片N、P含量及其化学计量学特征,并结合温度和降水气候数据研究了N、P含量及N:P比值与这两个气候因子的相关关系。研究结果显示:青藏高原草地群落水平的叶片N含量变化范围为14.8–36.7mg·g–1,平均为23.2mg·g–1;P含量变化范围为0.8–2.8mg·g–1,平均为1.7mg·g–1;N:P比值变化范围为6.8–25.6,平均为13.5。群落叶片N含量与P含量呈显著正相关关系,叶片的N:P比值与P含量呈显著负相关关系,N:P比值的变化主要由P含量变化决定。另外发现:群落水平叶片N、P含量及N:P比值存在着显著的年际变化,叶片的N、P含量及N:P比值与年平均气温之间存在着极显著的相关关系。通过该研究结果推测:P含量较高的变异系数及其与环境因子表现出的显著相关性,在一定程度上体现了植物群落对当地气候条件的一种适应。Aims Leaf N and P stoichiometry has been widely studied at the species level in both aquatic and terrestrial ecosystems, however, it lacks research at the community level. Since the ecological stoichiometric characteristics could play important roles in connecting different levels of ecological studies and former studies mainly focused on the individual level, in this study, we try to figure out the pattern of foliar N and P at the community level of grassland ecosystems in Qinghai-Tibetan Plateau. Additionally, we also try to find out the relationships between community level leaf N, P and site climate factors. Methods Leaf samples were collected from 47 research sites in Qinghai-Tibetan Plateau at the end of the growing season yearly from 2006 to 2008. We measured the leaf N concentrations by using an elemental analyzer and the leaf P concentration based on a molybdate/stannous chloride method. Climate data of annual mean temperature and annual mean precipitation （65 national standard stations） between 2006 and 2008 were used to interpolate into gridded data with a resolution of 1 km× 1 km through the tchebycheffian spline function. Important findings Leaf N, P concentrations and N：P ratios at the community level over the southern part of Qinghai-Tibetan Plateau were 23.2 mg·g^-1, 1.7 mg·g^-1 and 13.5, respectively. Significant inter-annual differences were presented in leaf N, P concentrations and N：P ratios. Mean annual temperature was strongly correlated with leaf N, P and N：P ratios. Besides, the correlations between climate factors and learN, P, N：P ratios were generally consistent with the previous results found at the global scale. Our results suggest that the high variation in leaf P concentration and its strong correlation with environmental factors reveal that, to some extent, stoichiometric traits at the community level are adaptive to local environmental conditions.

关 键 词：草原群落 叶片N、P含量 N:P比 青藏高原 

分 类 号：Q948[生物学—植物学]