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植物研究 ›› 2023, Vol. 43 ›› Issue (2): 194-206.doi: 10.7525/j.issn.1673-5102.2023.02.005

• 生理与生态 • 上一篇    下一篇

N添加对西南亚高山红桦林根系分泌物及其介导的养分转化过程的影响

徐正刚1, 许航1, 彭修涛1, 梁时军2, 刘榕1, 罗尚华1, 肖娟1()   

  1. 1.西华师范大学环境科学与工程学院,南充 637000
    2.四川省南充生态环境监测中心站,南充 637000
  • 收稿日期:2022-05-27 出版日期:2023-03-20 发布日期:2023-03-07
  • 通讯作者: 肖娟 E-mail:xiaojuanhj@163.com
  • 作者简介:徐正刚(1996—),男,硕士研究生,主要从事地下生态学研究。
  • 基金资助:
    国家自然科学青年基金项目(31700387);四川省科技厅计划项目(2021YJ0283);四川省教育厅创新训练项目(S202210638049);西华师范大学创新训练项目(cxcy2021201)

Effects of N addition on Root Exudates and Their Mediated Nutrient Rransformation Processes in a Betula albosinensis Burk Forest in Southwest China

Zhenggang XU1, Hang XU1, Xiutao PENG1, Shijun LIANG2, Rong LIU1, Shanghua LUO1, Juan XIAO1()   

  1. 1.School of Environmental Science and Engineering,West China Normal University,Nanchong 637000
    2.Sichuan Nanchong Ecological Environment Monitoring Center Station,Nanchong 637000
  • Received:2022-05-27 Online:2023-03-20 Published:2023-03-07
  • Contact: Juan XIAO E-mail:xiaojuanhj@163.com
  • About author:XU Zhenggang(1996—),male,postgraduate student,mainly engaged in underground ecology research.
  • Supported by:
    National Natural Science Youth Fund Project(31700387);Planned project of Sichuan Provincial Department of science and technology(2021YJ0283);Innovation training program of West China Normal University(cxcy2021201)

摘要:

目前缺乏对根系分泌物通量以及相关生态后果对不同氮(N)沉降水平响应方向和幅度的深入理解,该研究以西南亚高山典型的红桦(Betula albosinensis)林为研究对象,通过野外原位N添加试验模拟不同氮沉降水平(对照组,0 kg?hm-2?a-1;低氮处理,25 kg?hm-2?a-1;高氮处理,50 kg?hm-2?a-1),分析了红桦林根系分泌物C输入通量及其介导的根际土壤养分循环过程对不同N添加水平的差异化响应,试图揭示不同N添加处理对红桦根系分泌物C输入通量及其介导的土壤养分转化过程的影响。结果表明:(1)N添加显著抑制了红桦林根系分泌物C输入速率(其中低氮(N25)条件下单位根生物量根系分泌速率均值降低约14.87%)和年C输入通量(低氮条件下降低了约45.01%)(P<0.05),其高氮处理的抑制效应更强。(2)N添加显著抑制了红桦林N矿化速率及其相关的微生物胞外酶活性(P<0.05),并显著降低了其根际效应;N沉降显著抑制了根系分泌物C输入通量及其介导的土壤养分转化过程,并且这种抑制效应随N沉降水平的升高而增强。该研究结果可丰富全球气候变化下森林地下碳养分循环过程的认识和理解。

关键词: 红桦林, 根系分泌物, 土壤N转化, 根际效应, N沉降

Abstract:

At present, we still lack a deep understanding of the response direction and amplitude of root exudate flux and related ecological consequences to different nitrogen(N) deposition levels. In order to reveal the difference in the effects of different N addition treatments on root exudate C flux and its mediated soil nutrient transformation process, the typical Betula albosinensis Burk forest in the mountainous area of southwest China was used as materials, and different nitrogen deposition levels were simulated by in-situ N addition experiment(control group, 0 kg·hm-2?a-1); low nitrogen treatment, 25 kg·hm-2?a-1; High nitrogen treatment, 50 kg·hm-2?a-1 respectively. The results showed that: (1)N addition significantly reduced the C input rate(the average root exudation rate per unit root biomass decreased by 14.87% under low nitrogen(N25))and annual C input flux of root exudates(about 45.01% reduction under low nitrogen condition)(P<0.05), and high N treatment had stronger inhibition effect on root exudates C input. (2)N addition significantly inhibited soil N mineralization rate and related microbial extracellular enzyme activities(P<0.05), and significantly reduced its rhizosphere effect. In conclusion, N deposition significantly inhibited the root exudates C flux and its mediated soil nutrient transformation process, and this inhibition effect increased with the increase of N deposition level. The results could enrich the understanding of carbon-nutrient cycling in forest under global climate change.

Key words: Betula albosinensis Burk forest, root exudates, soil N transformation, rhizosphere effect, nitrogen deposition

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