青藏高原草地植物群落冠层叶片氮磷化学计量学分析

doi:10.3773/j.issn.1005-264x.2010.01.004

摘要/Abstract

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14.8-36.7 mg·g^-1, 平均为23.2 mg·g^-1; P含量变化范围为0.8-2.8 mg·g^-1, 平均为1.7 mg·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。

关键词: 草原群落, 叶片N、P含量, N:P比, 青藏高原

Abstract:

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 leaf N, 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.

Key words: grassland community, leaf N and P concentrations, N:P ratios, Qinghai-Tibetan Plateau

杨阔, 黄建辉, 董丹, 马文红, 贺金生. 青藏高原草地植物群落冠层叶片氮磷化学计量学分析. 植物生态学报, 2010, 34(1): 17-22. DOI: 10.3773/j.issn.1005-264x.2010.01.004

YANG Kuo, HUANG Jian-Hui, DONG Dan, MA Wen-Hong, HE Jin-Sheng. Canopy leaf N and P stoichiometry in grassland communities of Qinghai-Tibetan Plateau, China. Chinese Journal of Plant Ecology, 2010, 34(1): 17-22. DOI: 10.3773/j.issn.1005-264x.2010.01.004

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链接本文: https://www.plant-ecology.com/CN/10.3773/j.issn.1005-264x.2010.01.004

https://www.plant-ecology.com/CN/Y2010/V34/I1/17

图/表 6

图1 研究区植被类型及样地分布。

Fig. 1 Vegetation types of the study area and distribution of field sites.

表1 青藏高原草地群落水平叶片氮(N)、磷(P)含量及氮磷比值(N:P)化学计量学特征(2006-2008年)

Table 1 Statistical characteristics of leaf N, P concentrations and N:P ratios at the community level in the grassland of Qinghai-Tibetan Plateau (2006-2008)

年 Year	n	N (mg·g^-1)			P (mg·g^-1)			N:P
年 Year	n	AM/GM	SD	CV	AM/GM	SD	CV	AM/GM	SD	CV
2006	47	21.5/21.2	3.08	0.14	1.5/1.5	0.50	0.33	15.2/14.6	4.11	0.27
2007	43	26.2/25.7	4.85	0.18	1.5/1.7	0.37	0.21	15.4/15.2	2.46	0.16
2008	43	23.2/22.9	3.24	0.14	2.1/2.1	0.33	0.16	11.0/10.9	1.58	0.14
总计 Total	133	23.5/23.2	3.24	0.18	1.9/1.7	0.48	0.28	13.9/13.5	3.55	0.26

图2 叶片氮含量与磷含量相关关系图。

Fig. 2 Scatter plots showing the relationship between leaf N and leaf P concentrations.

图3 叶片磷含量与N:P比值相关关系图。

Fig. 3 Scatter plots showing the relationship between leaf N:P ratios and leaf P concentrations.

表2 叶片氮(N)、磷(P)含量和氮磷比值(N:P)之间及其与气候因子的相关性(Pearson检验)

Table 2 Correlations between leaf N, P concentrations, N:P ratios and climate factors (Pearson test)

	P	N:P	MAT	AP	GST	GSP
N	0.446^**	0.210^*	-0.265^**	0.205^*	-0.249^**	0.243^**
P		-0.782^**	-0.420^**	0.374^**	-0.449^**	0.300^**
N:P			0.274^**	-0.266^**	0.317^**	-0.159

图4 叶片N:P比值与年平均气温相关关系图。

Fig. 4 Scatter plots showing the relationship between leaf N:P ratios and mean annual temperature.

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