Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (2): 275-288.DOI: 10.17521/cjpe.2022.0090

• Research Articles • Previous Articles    

Differences and influencing factors of microbial carbon use efficiency in forest rhizosphere soils at different altitudes in Taibai Mountain, China

ZHANG Yao1, CHEN Lan1, WANG Jie-Ying1, LI Yi1, WANG Jun1,2, GUO Yao-Xin3, REN Cheng-Jie4, BAI Hong-Ying1, SUN Hao-Tian1, ZHAO Fa-Zhu1,2,*()   

  1. 1Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environment Science, Northwest University, Xi’an 710127, China
    2Shaanxi Key Laboratory for Carbon Neutral Technology, Northwest University, Xi’an 710127, China
    3The College of Life Sciences, Northwest University, Xi’an 710127, China
    4College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
  • Received:2022-03-09 Accepted:2022-07-06 Online:2023-02-20 Published:2023-02-28
  • Contact: *(
  • Supported by:
    2021 First Funds for Central Government to Guide Local Science and Technology Development in Qinghai Province(2021ZY002);Ministry of Education “Chunhui Plan” Cooperative Scientific Research Project


Aims Under the background of changing carbon cycle process in forest ecosystems caused by global environmental change, the microbial carbon use efficiency (CUE) in forest rhizosphere soil is critical to determine the strength of microbial anabolism and catabolism in forest ecosystems. However, the variation and influencing factors of microbial CUE in rhizosphere soils at different altitudes remain undetermined.

Methods Rhizosphere soil at six different altitudes spanning four forest belts in Taibai Mountain was sampled to determine the physical and chemical properties, extracellular enzyme activity, and characteristics of microbial community and vegetation. Based on the stoichiometric ratio, the soil microbial CUE was estimated. Furthermore, the variation in microbial CUE of rhizosphere soil along the altitude gradient was analyzed to quantify the influencing factors of microbial CUE.

Important findings The results showed that the microbial CUE of rhizosphere soil exhibited an overall upward trend with the increase in altitude. The microbial CUE increased by 4.36% from 0.505 at the lowest altitude to 0.527 at the highest altitude, but decreased at 1 603 and 2 405 m. Based on the Mantel analysis, we identified four categories of factors (i.e., altitude, soil matrix, vegetation and microbe) that related to microbial CUE in rhizosphere soil. The variations of microbial CUE in rhizosphere soil are affected by multiple environmental factors, with the dominant factor being soil matrix (such as dissolved organic carbon (DOC) content, ammonium nitrogen (NH+4-N) content), followed by vegetation. Furthermore, the altitude factor and the microbial factor explained 2.6% and 3.1% of the CUE change, respectively. Although the microbial factors exerted no significant impact on microbial CUE, soil matrix, vegetation and microbe jointly explained 47.0% of the microbial CUE change. The variance partitioning analysis (VPA) quantitatively revealed the contribution of environmental factors to the change of microbial CUE, where soil matrix and vegetation explained 17.0% and 5.7% of the variation, respectively. While the interaction between soil matrix and vegetation accounted for 31.9% of the changes in microbial CUE. The above results indicated that the high-altitude rhizosphere soil in Taibai Mountain has a high carbon sequestration potential, and the carbon sequestration of forest rhizosphere soil may decrease with the intensification of global warming. The vertical temperature difference and the vertical differentiation of the vegetation belt induced by altitude gradient will alter the growth and metabolism environment of microorganisms in the rhizosphere soil. The comprehensive effect of multiple environmental factors dominated by soil matrix impacts the CUE of soil microorganisms, and ultimately changes the assimilation and catabolism processes of soil carbon. The results of this study can provide a scientific basis for the carbon assimilation capacity and carbon sequestration potential of forest soil microorganisms in Qinling Mountains, as well as the forest soil carbon cycle under the background of global change.

Key words: rhizosphere soil, microbial carbon use efficiency, altitude gradient, forest ecosystem, Qinling Mountains