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五角槭根系的负激发效应降低了异养呼吸及其温度敏感性

曲桂芳1,2,徐文华1,王会1,2,彭勃1,2,高德才1,2,孙建飞1,2,郑俊强1,姜萍1,白娥1*#br#   

  1. (1中国科学院沈阳应用生态研究所, 沈阳 110164; 2中国科学院大学, 北京 100049)
  • 出版日期:2016-10-10 发布日期:2016-10-10

Negative priming effect of maple roots reduced heterotrophic respiration and its temperature sensitivity.

QU Gui-fang1,2, XU Wen-hua1, WANG Hui1,2, PENG Bo1,2, GAO De-cai1,2, SUN Jian-fei1,2, ZHENG Jun-qiang1, JIANG Ping1, BAI Edith1*#br#   

  1. (1Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China; 2University of Chinese Academy of Sciences, Beijing 100049, China).
  • Online:2016-10-10 Published:2016-10-10

摘要: 土壤呼吸(Rs)由自养呼吸(Ra)和异养呼吸(Rh)组成,这两个组分温度敏感性的差异性存在较大争议,而根际激发效应对Rh呼吸速率及其温度敏感性(Q10)的影响导致这一问题更为复杂化。本研究采用13C自然丰度法,将中国北方温带次生林的重要建群树种C3植物五角槭种植于曾经连续23年种植玉米的C4土壤中,以此区分RaRh,并探讨RaRh温度敏感性的差异性以及根际激发效应对Rh呼吸速率和Q10的影响。结果表明:植物根系对Rh呼吸速率有负激发效应,并降低了Rh的温度敏感性;植树土壤的Rh比不植树土壤的无根异养呼吸(Rhf)降低了34.3%,RhQ10值(1.51)也显著低于RhfQ10值(2.07),而RaQ10值(3.89)是RhQ10值的2.5倍;因此,未来研究在区分RaRh呼吸速率和温度敏感性时,应该考虑根际激发效应对Rh及其温度敏感性的影响,这对于精确评估和模型模拟气候变化背景下Rs的变化和响应具有重要意义。

关键词: 放牧梯度, 生活型功能群, 叶片性状, 克氏针茅草原

Abstract: Soil respiration (Rs) comprises autotrophic (Ra) and heterotrophic (Rh) respiration. The difference in temperature sensitivity (Q10) between Ra and Rh is still under debate. Rhizosphere priming effect (RPE) plays an important role in affecting the temperature sensitivity of Rh, which makes the issue more complex. Here we used the 13C natural abundance method by planting Acer mono (C3 plant) in microcosms with maize soil (soil with cultivation of C4 maize for 23 years) to investigate the responses of Ra and Rh to temperature change and the role of RPE. An overall negative RPE was observed in the growing season, which reduced Rh and its Q10 value by 34.3% and 27.0%, respectively. The Q10 value of Ra (3.89) was 2.5 times higher than that of Rh (1.51). Our results highlight the importance of plant roots in regulating the response of Rs to temperature, which should be considered in models of soil respiration in the future.

Key words: life-form functional group, leaf trait, Stipa krylovii steppe., grazing gradient