植物生态学报 ›› 2023, Vol. 47 ›› Issue (7): 922-931.DOI: 10.17521/cjpe.2022.0105

所属专题: 生态化学计量

• 研究论文 • 上一篇    下一篇

高寒草甸表层土壤和优势植物叶片的化学计量特征对降水改变和氮添加的响应

李红琴1,2,3, 张法伟2,3,4,*(), 仪律北5   

  1. 1洛阳师范学院生命科学学院, 河南洛阳 471934
    2中国科学院三江源国家公园研究院, 西宁 810008
    3国家生态科学数据中心, 北京 100101
    4中国科学院西北高原生物研究所高原生物适应与进化重点实验室, 西宁 810008
    5青海省林业和草原局林业碳汇服务中心, 西宁 810008
  • 收稿日期:2022-03-25 接受日期:2022-07-15 出版日期:2023-07-20 发布日期:2023-07-21
  • 通讯作者: *张法伟(mywing963@126.com)
  • 作者简介:ORCID: 张法伟: 0000-0003-0693-7956
  • 基金资助:
    国家重点研发计划(2017YFA0604802);国家生态科学数据中心开放基金项目(NESDC20210203);中国科学院-青海省人民政府三江源国家公园联合研究专项(LHZX-2020-07);青海省科技成果转化专项(2020-SF-145)

Stoichiometric responses in topsoil and leaf of dominant species to precipitation change and nitrogen addition in an alpine meadow

LI Hong-Qin1,2,3, ZHANG Fa-Wei2,3,4,*(), YI Lü-Bei5   

  1. 1College of Life Sciences, Luoyang Normal University, Luoyang, Henan 471934, China
    2Institute of Sanjiangyuan National Park, Chinese Academy of Sciences, Xining 810008, China
    3National Ecosystem Science Data Center, Beijing 100101, China
    4Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
    5Forestry Carbon Sink Service Center, Qinghai Forestry and Grassland Administration, Xining 810008, China
  • Received:2022-03-25 Accepted:2022-07-15 Online:2023-07-20 Published:2023-07-21
  • Contact: *ZHANG Fa-Wei(mywing963@126.com)
  • Supported by:
    The National Key R&D Program of China(2017YFA0604802);The National Ecosystem Science Data Center(NESDC20210203);The Chinese Academy of Sciences-People’s Government of Qinghai Province Joint Grant on Sanjiangyuan National Park Research(LHZX-2020-07);The Project of Transformation of Scientific and Technological Achievements of Qinghai Province(2020-SF-145)

摘要:

降水格局改变和氮沉降增加是草地生态系统结构及功能演变的重要影响因素, 其对高寒草甸土壤和植物的化学计量的影响存在很大变异, 限制了对高寒草甸生态功能预测的准确性。该研究基于祁连山东段南麓高寒草甸降水改变(减雨50%和增雨50%)和氮添加(10 g·m-2·a-1)的控制实验平台, 分析了2017-2020年表层(0-10 cm)土壤有机碳、全氮、全磷含量和优势植物麻花艽(Gentiana straminea)、垂穗披碱草(Elymus nutans)、黄花棘豆(Oxytropis ochrocephala)和矮生嵩草(Kobresia humilis)的叶片碳(LC)、氮(LN)、磷(LP)和钾(LK)含量等变化, 以明晰土壤和植物的化学计量特征对降水改变和氮添加的响应。结果表明, 土壤化学计量特征的变异存在显著年际效应, 与实验处理无显著关系。地上活体生物量(PB)存在显著的年际差异, 并受到氮添加的显著影响。优势物种叶片化学计量特征的变异因物种而异。垂穗披碱草叶片化学计量特征的变化均不显著, 属于资源保守型物种, 而矮生嵩草的变化显著, 敏感性较强。基于处理样地与对照样地每年指标相对变化(Δ)的分析表明, 氮添加显著提高了ΔPB达15.6%。降水减少显著降低了黄花棘豆ΔLC达6.8%, 增加了矮生嵩草ΔLP达19.8%。研究表明仅氮添加提高了PB, 降水减少改变了部分物种LC和LP含量, 土壤和植物叶片的化学计量特征变异的年际效应或物种效应大于实验处理效应, 凸显了高寒草甸生态系统对降水改变和氮添加响应的复杂性。

关键词: 高寒草甸, 降水改变, 氮添加, 化学计量, 优势植物

Abstract:

Aims Precipitation regime alteration and increasing nitrogen deposition have substantially altered the structure and function of grassland ecosystems. However, the responses of stoichiometry in soil and vegetation remain elusive, which limits the accuracy in predicting functional changes of alpine meadow.

Methods Based on a manipulation experiment platform of nitrogen addition (10 g·m-2·a-1) and precipitation change (precipitation reduction by 50% and increase by 50%) in an alpine meadow on the southern foot of Qilian Mountains, organic carbon (SOC), total nitrogen (SN), total phosphorus (SP) contents in topsoil (0-10 cm), and foliar carbon (LC), nitrogen (LN), phosphorus (LP) and potassium (LK) contents of dominant plant species, including Gentiana straminea, Elymus nutans, Oxytropis ochrocephalaand Kobresia humilis,were continuously surveyed from 2017 to 2020.

Important findings The soil stoichiometry varied significantly among different years, but was not affected by experimental treatments. The aboveground plant biomass showed inter-annual variations and was significantly affected by nitrogen addition. The responses of leaf stoichiometry were species-specific. Foliar stoichiometry of a resource-conservative species, E. nutans, showed limited variations, while that of the sensitive species, K. humilis, fluctuated significantly. To exclude the impacts of temporal variations, we conducted the analysis based on the relative changes (Δ) between treatment plots and the control plots from the same year and the results showed that nitrogen addition significantly increased ΔPB by 15.6%. Precipitation reduction significantly decreased ΔLC of O. ochrocephala by 6.8% while increased ΔLP of K. humilis by 19.8%. Our findings suggest that only nitrogen addition increased aboveground biomass and precipitation reduction altered LC and LP contents in some plant species. The temporal or species-specific effect, rather than experiment treatments effect, dominated the stoichiometric variations of soil and vegetation, highlighting the complex responses of alpine meadow to precipitation regime alteration and nitrogen addition.

Key words: alpine meadow, precipitation change, nitrogen addition, stoichiometry, dominant plant species