Liu Xinping, Luo Yongqing, Cheng Li, Hu Hongjiao, Wang Youhan, Du Zhong
Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
School of Geographical Sciences, China West Normal University, Nanchong, China.
Front Plant Sci. 2021 Sep 1;12:698054. doi: 10.3389/fpls.2021.698054. eCollection 2021.
Plant fine root turnover is a continuous process both spatially and temporally, and fine root decomposition is affected by many biotic and abiotic factors. However, the effect of the living roots and the associated mycorrhizal fungal mycelia on fine root decomposition remains unclear. The objective of this study is to explore the influence of these biotic factors on fine root decomposition in a semi-arid ecosystem. In this study, we investigated the effect of fine roots and mycelia on fine root decomposition of a pioneer shrub () in Horqin sandy land, northeast China, by the ingrowth core method combined with the litterbag method. Litterbags were installed in cores. Results showed that core a allowed the growth of both fine roots and mycelia (treatment R + M), core b only allowed the growth of mycelia (treatment M), and in core c the fine root and mycelia growth were restricted and only bulk soil was present (treatment S). These findings suggest that the process of root decomposition was significantly affected by the living roots and mycelia, and carbon (C) and nitrogen (N) concentration dynamics during root decomposition differed among treatments. Mycelia significantly stimulated the mass loss and C and N release during root decomposition. Treatment R + M significantly stimulated the accumulation of soil total C, total N, and organic N under litterbags. The mycelia significantly stimulated the accumulation of the inorganic N (ammonium-N and nitrate-N) but the presence of fine roots weakened nitrate-N accumulation. The presence of living roots and associated mycelia strongly affected the process of root decomposition and matter release in the litter-soil system. The results of this study should strengthen the understanding of root-soil interactions.
植物细根周转在空间和时间上都是一个连续的过程，细根分解受许多生物和非生物因素影响。然而，活根及相关菌根真菌菌丝体对细根分解的影响仍不清楚。本研究的目的是探讨这些生物因素对半干旱生态系统中细根分解的影响。在本研究中，我们采用埋芯法结合凋落物袋法，研究了中国东北科尔沁沙地先锋灌木（）的细根和菌丝体对细根分解的影响。在芯中设置凋落物袋。结果表明，芯a允许细根和菌丝体生长（处理R+M），芯b仅允许菌丝体生长（处理M），芯c中细根和菌丝体生长受到限制，仅存在原状土（处理S）。这些结果表明，根分解过程受活根和菌丝体的显著影响，且根分解过程中碳（C）和氮（N）浓度动态在不同处理间存在差异。菌丝体显著促进了根分解过程中的质量损失以及C和N的释放。处理R+M显著促进了凋落物袋下土壤总C、总N和有机N的积累。菌丝体显著促进了无机N（铵态N和硝态N）的积累，但细根的存在削弱了硝态N的积累。活根和相关菌丝体的存在强烈影响了凋落物-土壤系统中的根分解过程和物质释放。本研究结果应能加强对根-土相互作用的理解。
