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草业学报 ›› 2022, Vol. 31 ›› Issue (9): 50-62.DOI: 10.11686/cyxb2021496

• 研究论文 • 上一篇    下一篇

高寒草甸植物叶片生态化学计量特征对长期氮肥添加的响应

游郭虹(), 刘丹, 王艳丽, 王长庭()   

  1. 西南民族大学青藏高原研究院,四川 成都 610041
  • 收稿日期:2021-12-28 修回日期:2022-03-09 出版日期:2022-09-20 发布日期:2022-08-12
  • 通讯作者: 王长庭
  • 作者简介:Corresponding author. E-mail: wangct@swun.edu.cn
    游郭虹(1994-),女,山东滨州人,在读硕士。E-mail: 1294302971@qq.com
  • 基金资助:
    国家自然科学基金项目(U20A2008);第二次青藏高原综合科学考察研究项目(2019QZKK0302)

Response of plant leaf ecological stoichiometric characteristics to long-term nitrogen addition in alpine meadow

Guo-hong YOU(), Dan LIU, Yan-li WANG, Chang-ting WANG()   

  1. Institute of Qinghai-Tibetan Plateau,Southwest Minzu University,Chengdu 610041,China
  • Received:2021-12-28 Revised:2022-03-09 Online:2022-09-20 Published:2022-08-12
  • Contact: Chang-ting WANG

摘要:

氮(N)是植物生长发育所需的基本元素,人为N添加已成为陆地生态系统N输入的主要形式。施N作为改善土壤养分条件的重要途径,可改变土壤理化性质,也会对植物叶片生态化学计量特征产生影响。本研究在2012年5月设置0(CK)、10(N10)、20(N20)、30(N30) g·m-2·a-1的N添加试验,并于2018年8月采集禾本科、莎草科、豆科和杂类草叶片,测定其碳(C)、N、磷(P)含量,分析不同水平N添加下植物叶片生态化学计量特征的差异,探索长期N添加下植物叶片生态化学计量特征变化的影响因素。结果表明:1)N添加显著提高了禾本科叶片碳(LC)含量而显著降低了豆科LC含量(P<0.05),莎草科和杂类草LC含量变化不显著(P>0.05)。随施N量增加,4种功能群叶片氮(LN)含量均显著增加(P<0.05),而叶片磷(LP)含量变化趋势不一致。2)N添加下4种功能群植物叶片碳氮比(LC/N)整体呈下降趋势,叶片氮磷比(LN/P)和叶片碳磷比(LC/P)呈上升趋势。3)土壤含水量(SMC)与植物叶片各项指标均显著相关(P<0.05),SMC对植物叶片生态化学计量特征变化的贡献率最高(10.28%,P<0.001)。4种功能群中,杂类草对SMC变化的响应最敏感,表现为杂类草LN、LN/P和LC/P随SMC增加显著降低而LC/N和LP显著升高。综上所述,4种功能群植物叶片生态化学计量特征对N添加的响应存在差异,N添加下影响植物叶片生态化学计量特征变化的重要因子是SMC。

关键词: 氮添加, 生态化学计量, 高寒草甸, 植物叶片, 土壤

Abstract:

Nitrogen (N) is critical to plant growth and anthropogenic N addition has been a main source of N input in many terrestrial ecosystems. As an important method for modifying soil nutrient status, N addition affects soil physicochemical properties which in turn affect leaf ecological stoichiometric characteristics. In order to study the effect of N addition on leaf ecological stoichiometric characteristics, we conducted an N fertilization experiment in an alpine meadow on the Qinghai-Tibetan Plateau. The N addition experiment was established in May 2012 with four treatments: 0 (CK), 10 (N10), 20 (N20), 30 (N30) g·m-2·yr-1. We collected leaves from grass, sedge, legume and forb in August, 2018, and we measured the leaf carbon (C), N and phosphorus (P) contents. Data from the four treatments were compared and differences in leaf carbon (LC), leaf nitrogen (LN), leaf phosphorus (LP) and their stoichiometric ratio among treatments were identified, and analyses were conducted to determine environmental factors influencing leaf ecological stoichiometric characteristics. It was found that: 1) N addition significantly increased the leaf carbon (LC) content of grass, but significantly decreased the LC content of legume, and LC content of sedge and forb was not significantly changed (P>0.05). The LN of the four plant functional groups increased markedly with increasing N addition (P<0.05), but the LP of the four plant functional groups varied inconsistently. 2) In general, the LC/N of the four plant functional groups decreased, while the LN/P and LC/P increased with increasing N addition. 3) Soil moisture content (SMC) was significantly (P<0.05) correlated with plant LC, LN, LP, LC/N, LN/P and LC/P in all cases, and SMC contributed mostly to the variance of the leaf ecological stoichiometry (10.28%, P<0.001). Compared with grass, sedge and legume, the responses of forb to SMC was relatively sensitive. The LN, LN/P and LC/P of forb decreased but the LC/N and LP of forb increased linearly with SMC. In summary, the responses of the four plant functional groups to N addition differed; SMC was the key factor influencing the change in leaf ecological stoichiometric characteristics of the four plant functional groups N addition.

Key words: nitrogen addition, ecological stoichiometry, alpine meadow, plant leaf, soil