矿区复垦地接菌驱动植物−土壤系统中光合碳分配与稳定机制

Mechanisms of carbon distribution and stability in the photosynthetic processes of plant-soil systems influenced by arbuscular mycorrhizal fungi during reclamation of mining areas

  • 摘要: 接种丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)与植被恢复联合已成为矿区沉陷地生态修复关键复垦技术,探究菌根修复多年后矿区植物光合碳在植物−土壤系统中的积累与分配现状及稳定机制,对于深入明晰矿区菌根复垦后植物−土壤碳固定流动过程、实现矿区固碳增汇具有重要意义。为此,在大柳塔菌根修复试验示范区紫穗槐样地的接菌区与对照区,设计原位13C同位素脉冲标记试验,结合碳同位素及代谢组学的方法,研究长期菌根复垦下矿区光合碳在植物−土壤系统中的分配及稳定策略。结果表明:叶片光合固碳后沿叶—茎—根—土的路径向下运移,长期菌根修复能增加光合碳在矿区植物−土壤系统中的积累量,标记接菌区平均光合碳富集总量是标记对照区的1.3倍;接菌提高光合碳向地下部(植物根系及土壤)的分配比例,标记接菌区地下部分配比例及平均富集量比标记对照区多13.4%,299.3%。光合碳13C进入土壤后,更多地以矿物结合态有机碳(MAOC)形式存在,其中光合碳13C在MAOC中的平均富集量标记接菌区比标记对照区多分配了246.8%,标记接菌区13C-MBC净富集量是标记对照区的4.5倍,维持了土壤碳库的稳定,同时菌根提高土壤有机碳转化的能力,有利于光合碳在土壤中的固存。结合代谢组学的结果发现,AMF菌丝网络通过调节脂质和类脂分子、有机杂环化合物、有机氧化物、苯丙烷和聚酮类等相关化合物的代谢,影响了酪氨酸代谢、糖解与糖代谢合成、氨基糖和核苷酸糖等碳代谢途径,最终实现土壤中光合碳13C的富集以及有机碳库的稳定。综上,微生物菌根复垦既可以促进土壤有机碳库积累,又可以调控有机碳库的转化与稳定,是矿区土壤实现固碳增汇的优选方法之一。

     

    Abstract: Inoculation of Arbuscular Mycorrhizal Fungi (AMF) combined with vegetation restoration has become a key reclamation technology for ecological restoration in mining subsidence. Investigating the accumulation and distribution of photosynthetic carbon sequestration within the plant-soil system following years of mycorrhizal restoration holds significant importance for elucidating the carbon cycling processes in reclaimed soils of mining regions and achieving effective carbon sequestration. The distribution strategy of photosynthetic carbon in the plant-soil system under long-term mycorrhizal cultivation was studied in the AMF area and the control area of Daliuta Mycorrhizal bioreclamation experimental demonstration area by 13C isotope pulse labeling method and metabolic. The results are summarized as follows: Following leaf carbon sequestration, there was a downward transfer of carbon to the leaf, stem, root, and soil. Long-term mycorrhizal restoration significantly enhanced the accumulation of photosynthetic carbon within the plant-soil system in the mining area. The average photosynthetic carbon enrichment amount in the labeled AMF area was 1.33 times greater than that observed in the labeled control area. Additionally, the distribution ratio of photosynthetic carbon to the underground (plant roots and soil) was increased by inoculation, and the distribution ratio and average enrichment in the underground part of the labeled inoculation area were 13.4% and 299.3% higher than those in the labeled control area. More photosynthetic carbon 13C was present in the form of mineral-bound organic carbon(MAOC) after entering the soil. The average enrichment amount of photosynthetic carbon 13C in MAOC was 246.8% more than that in the labeled control area. Furthermore, mycorrhiza improved the ability of soil organic carbon conversion and the net enrichment of 13C-MBC in the labeled AMF area was 4.5 times that in the labeled control area, thereby contributing to soil carbon stability. Meanwhile, mycorrhizal associations enhance soil organic carbon conversion efficiency, facilitating the retention of photosynthetic carbon within the soil. Combined with the results of metabolomics, it was found that AMF mycelial network affected the carbon metabolism pathway of tyrosine metabolism, glycolysis and glycolysis synthesis, amino acid and nucleotide sugars synthesis respectively. This regulation occurred through the metabolism of lipid and lipid molecules, organic heterocyclic compounds, organic oxides, phenylpropane and polyketones, ultimately affecting the enrichment of photo-synthetic carbon 13C in soil and the stability of organic carbon pool. In general, microbial mycorrhizal reclamation can not only promote the accumulation of soil organic carbon pool, but also regulate the transformation and stability of organic carbon pool, which is one of the most effective methods to accelerate the realization of carbon reduction and carbon sink increase in mining area.

     

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