Abstract：
Vegetation restoration can effectively improve the ecological environment of mining areas, enhance the ecological service function, and promote the carbon sequestration and sink increase in the ecosystem. The soil carbon cycle plays an important role in the biogeochemical cycle. The abundance of functional genes can predict the material cycling potential and metabolic characteristics of soil microorganisms. Previous studies on functional microorganisms have mainly focused on large ecosystems such as farmland, forest, and wetland, but relatively little attention has been paid to complex ecosystems with great anthropogenic interference and special functions, such as mines. Clarifying the succession and driving mechanism of functional microorganisms in reclaimed soil under the guidance of vegetation restoration is helpful to fully explore how functional microorganisms change with the change in abiotic and biotic conditions. Therefore, 25 topsoil samples were collected from grassland (GL), brushland (BL), coniferous forests (CF), broadleaf forests (BF), and mixed coniferous and broadleaf forests (MF) in the reclamation area of the Heidaigou open pit waste dump on the Loess Plateau. The absolute abundance of soil carbon cycle functional genes was determined using real-time fluorescence quantitative PCR to explore the effect of vegetation restoration on the abundance of carbon cycle-related functional genes in soil and its internal mechanism. The results showed that:① the effects of different vegetation restoration types on the chemical properties of reclaimed soil and the abundance of functional genes related to the carbon cycle were significantly different (P<0.05). GL and BL showed significantly better accumulation of soil organic carbon, total nitrogen, and nitrate nitrogen (P<0.05) than that in CF. ② The gene abundance of rbcL, acsA, and mct was the highest among all carbon fixation genes. The abundance of functional genes related to carbon cycle in BF soil was higher than that in other types, which was closely related to the high activity of ammonium nitrogen and BG enzymes and the low activity of readily oxidized organic carbon and urease in BF soil. The functional gene abundance of carbon degradation and methane metabolism was positively correlated with ammonium nitrogen and BG enzyme activity and negatively correlated with organic carbon, total nitrogen, readily oxidized organic carbon, nitrate nitrogen, and urease activity (P<0.05). ③ Different vegetation types could directly affect soil BG enzyme activity or affect soil nitrate nitrogen content, thus indirectly affecting BG enzyme activity, in turn manipulating the abundance of functional genes related to the carbon cycle. This study is helpful to understand the effects of different vegetation restoration types on the functional genes related to the carbon cycle in the soil of mining areas on the Loess Plateau and provides a scientific basis for ecological restoration and ecological carbon sequestration and sink enhancement in mining areas.
摘要：
植被恢复能有效改善矿区生态环境,增强生态服务功能，并促进生态系统中的碳汇和碳汇增加。土壤碳循环在生物地球化学循环中起着重要作用。功能基因的丰度可以预测土壤微生物的物质循环潜力和代谢特征。以前对功能微生物的研究主要集中在农田等大型生态系统上,森林,和湿地，但是对具有巨大人为干扰和特殊功能的复杂生态系统的关注相对较少，比如地雷。明确植被恢复指导下复垦土壤中功能微生物的演替和驱动机制,有助于充分探索功能微生物如何随着非生物和生物条件的变化而变化。因此,从草地（GL）收集了25个表层土壤样品，灌木丛(BL)，针叶林（CF），阔叶林（BF），黄土高原黑戴沟露天垃圾场开垦区的针叶阔叶混交林（MF）。采用实时荧光定量PCR测定土壤碳循环功能基因的绝对丰度,探讨植被恢复对土壤碳循环相关功能基因丰度的影响及其内在机制。结果表明:①不同植被恢复类型对复垦土壤化学性质和碳循环相关功能基因丰度的影响差异显著(P<0.05)。GL和BL表现出明显的土壤有机碳积累，总氮,和硝酸盐氮（P<0.05）比CF。②rbcL的基因丰度,ACSA,mct在所有碳固定基因中最高。高炉土壤碳循环相关功能基因丰度高于其他类型,这与高炉土壤中铵态氮和BG酶的高活性以及易氧化有机碳和脲酶的低活性密切相关。碳降解和甲烷代谢的功能基因丰度与铵态氮和BG酶活性呈正相关,与有机碳,总氮,容易氧化的有机碳，硝酸盐氮,脲酶活性(P<0.05)。③不同植被类型可直接影响土壤BG酶活性或影响土壤硝态氮含量,从而间接影响BG酶活性，反过来操纵与碳循环相关的功能基因的丰度。本研究有助于了解黄土高原矿区不同植被恢复类型对土壤碳循环相关功能基因的影响,为矿区生态恢复和生态碳固汇强化提供科学依据。
