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短花针茅荒漠草原不同斑块优势种植物的C,N,P化学计量特征
于瑞鑫1,2, 王磊1,2,3, 杨新国1,2, 田娜1,2, 王兴1,2, 宋乃平1,2
1.宁夏大学 西北土地退化与生态系统恢复省部共建国家重点实验室培育基地, 宁夏 银川 750021;2.宁夏大学 西北退化生态系统恢复与重建教育部重点实验室, 宁夏 银川 750021;3.南京大学 国际地球系统科学研究所, 江苏 南京 210093
摘要:
[目的]研究斑块中优势种的生活史策略及对养分限制的响应,以及优势种生态化学计量学特征随季节变化的响应规律,为植物种群演替及变化过程研究提供科学依据。[方法]确定3类典型斑块:斑块A (短花针茅)、斑块B (短花针茅+草木樨状黄耆)、斑块C (猪毛蒿+苦豆子+老瓜头),测定优势种的全碳、全氮、全磷含量,计算C:N,C:P,N:P并进行方差分析。采用线性回归分析法对不同斑块C,N,P化学计量进行逐步回归分析。[结果]各斑块优势种的C,N,P及其计量比特征在生长季内的变化规律不同,且各指标季节间的变化特征在不同斑块之间也存在差异;植物C含量在不同优势种和不同斑块间的差异均不显著;短花针茅N含量显著小于其他优势种,导致斑块A的N含量总体显著小于另外两个斑块;植物P含量在斑块A中随着季节的变化表现为增长的趋势,而在斑块C中表现为先减小后增大的变化过程;斑块A植物的C:N值无显著的季节变化,C:P和N:P值在春季显著高于夏秋季;斑块B和斑块C不同优势种的C:N,C:P和N:P值均表现出显著的差异性,但随季节变化过程不同,斑块B除C:N值外均表现出下降的趋势,而斑块C各比值均表现出先增大后减小的变化规律。[结论]3种斑块C,N,P含量表现出不同的相关性;斑块A表现为防御性策略,斑块B表现为竞争性策略,而斑块C表现为竞争性和防御性策略共存。
关键词:  C,N,P化学计量特征  季节变化  优势种  荒漠草原
DOI:10.13961/j.cnki.stbctb.2019.04.006
分类号:Q948.1
基金项目:国家重点研发计划专题"限制放牧退化草地补播和改良技术集成与示范"(2016YFC0500700);国家自然科学基金项目"荒漠草原不同叶型草地群落冠层光谱尺度效应及叶面积指数反演"(31760707);宁夏回族自治区西部一流学科建设项目(NXYLXK2017B06)
C, N, P Stoichiometric Characteristics of Different Dominant Species in Stipa Breviflora Desert Steppe
Yu Ruixin1,2, Wang Lei1,2,3, Yang Xinguo1,2, Tian Na1,2, Wang Xing1,2, Song Naiping1,2
1.Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China;2.Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China of Ministry of Education, Ningxia University, Yinchuan, Ningxia 750021, China;3.International Institute for Earth System Science, Nanjing University, Nanjing, Jiangsu 210093, China
Abstract:
[Objective] The life history strategies of dominant species in patches and their responses to nutrient restriction, stoichiometry characterization of dominant species were studied in response to seasonal variation, which was expected to provid a scientific basis for the study of plant population succession and change process.[Methods] 3 typical patches, patch A(Stipa breviflora), patch B(Stipa breviflora+Astragalus melilotoides), patch C(Artemisia scoparia+Sophora alopecuroides+Cynanchum komarovii) were recognized and in which the dominated species were sampled, and its total carbon, total nitrogen, and total phosphorus contents were measured. Ratios of C:N, C:P, N:P were calculated and analysis of their variances were conducted. Stepwise linear regression analysis of stoichiometry of the patches was performed.[Results] The results showed that the changes of carbon(C), nitrogen(N), phosphorus(P) and their stoichiometry characterization of the dominant species in three patches were different during the growing season, and the seasonal variation characteristics were also different among the three patchesseason. The contents of C among the dominant species, and among the patches as well, had no significant differences. N content of S. breviflora was lower than than the values of other dominant species, which resulted to the significantly smaller level of the N content in patch A. P content of patch A increased along the growing season, while of patch C, it experienced an initial decrease and a succeeding increased. For patch A plants, there was no significant seasonal variation in C:N values, the values of C:P and N:P were significantly higher in spring than those in summer and in autumn. C:N, C:P and N:P values of the dominant species in patches B and C had significant differences. However, the seasonal variation was different:for patch B all values decreased except of C:N value, C:N, C:P and N:P values of patch C all increased first and then decreased.[Conclusion] The C, N, and P contents of three patches showed different correlations, patch A showed a defensive strategy, patch B showed a competitive strategy, while patch C showed a coexistence of competitive and defensive strategies.
Key words:  C, N, P stoichiometric characteristics  seasonal variations  dominant species  desert steppe