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边坡生态修复工程植被恢复对土壤AMF定殖的影响

Impact of vegetation restoration techniques in slope ecological engineering on AMF colonization in soils

  • 摘要: 为探究植被混凝土修复边坡植被恢复过程中丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)定殖特征、土壤生物化学性质及其两者耦合关系,进一步认识植被混凝土基材中菌根生态效应,为后续将AMF应用到边坡植被恢复中,改善植物和根系周围环境,达到改善边坡生态系统稳定性的目的提供科学依据。采用空间代替时间方法,选取不同恢复年限的植被混凝土修复边坡(2、3、5、15 a),以自然恢复地(N1)及次生林(N2)作为对照,对AMF定殖特征和土壤生物化学性质进行测定分析。结果表明:各植被混凝土修复样地的AMF总侵染率均显著高于N2(P<0.05)。随着恢复年限的增加,AMF总侵染率表现先上升后降低趋势,在5 a样地较高,达到69.93%。植被混凝土修复样地微生物量碳、微生物量氮和微生物量磷含量分别在0.47~1.07、3.47~16.51、14.77~77.60 mg/kg之间,但次生林微生物量碳含量、自然恢复地微生物量磷含量均显著高于植被混凝土修复样地(P<0.05)。AMF定殖特征和土壤生物化学性质相关性分析显示微生物量碳和土壤蔗糖酶均与侵染率相关(P<0.05),但冗余分析和回归方程明确微生物量碳是侵染率的直接驱动因子。研究表明,在植被混凝土修复边坡植被恢复过程中,AMF均能侵染植物根系形成共生体。相较于自然恢复地和次生林,植被混凝土修复措施能促进AMF定殖和生长。建议使用植被混凝土技术修复边坡时通过调控基材水分和养分促进AMF定殖,在修复3~5 a时强化微生物管理以优化生态效益。本研究为边坡工程中菌根技术的应用提供了理论依据和量化指标。

     

    Abstract: This study systematically investigated the colonization dynamics of arbuscular mycorrhizal fungi (AMF) and their interactions with soil biochemical properties during slope restoration using vegetation concrete technology. The study aims to understand the mycorrhizal ecological effects in vegetation concrete substrates, and provides valuable information for the subsequent application of AMF in the restoration of slope vegetation, enhancing root-zone environments, and achieving the goal of enhancing the stability of slope ecosystems. The study, conducted in Yichang City, Hubei Province, China, utilized the space-for-time substitution method. Vegetation concrete slopes with different restoration durations (2, 3, 5, and 15 a) were selected, with naturally restored slope (15 a) and secondary forest (30 a) serving as controls. In each plot, five 1 m × 1 m quadrats were randomly selected for vegetation survey, within which five 0.25 m × 0.25 m sub-quadrats were sampled within each quadrat. Root samples collected using a mixed sampling approach based on the biomass proportion of dominant plants was employed to ensure the representativeness of host plants. AMF colonization characteristics were quantified using acetic acid ink staining and microporous membrane filtration. Microbial biomass carbon(MBC), microbial biomass nitrogen(MBN), and microbial biomass phosphorus (MBP) were measured using the chloroform fumigation method, and enzyme activities (invertase, urease, catalase, alkaline phosphatase) were analyzed colorimetrically. Pearson correlation, redundancy analysis, and stepwise regression were employed to identify key environmental driving factors. The results indicated that, except for the C1 and N2, the total AMF colonization rates in the remaining plots were all above 60%, classified as high colonization. Across all the plots, the total AMF colonization rates followed a unimodal curve during the vegetation restoration process, reaching their optimum in the mid-restoration phase (3-5 a), with a rate of 69.93% at 5 years, significantly higher than the 44.09% in secondary forest controls. Among the plots, the hyphal colonization rate contributed the most to the total colonization rate, accounting for 80.03%-98.57%, followed by the vesicular colonization rate, while the arbuscular colonization rate contributed the least to the total colonization rate, with a maximum of only 0.05% of the total colonization. The MBC, MBN, and MBP contents in the vegetation concrete restoration plots ranged from 0.47-1.07, 3.47-16.51, and 14.77-77.60 mg/kg, respectively. The activities of invertase(INV), urease(URE), alkaline phosphatase(ALP), and catalase(CAT) in the vegetation concrete restoration plots ranged from 72.11-179.15, 4.09-12.21, 29.85-34.77, and 8.12-12.16 mg/g, respectively. The correlation analysis between AMF growth and soil environmental factors showed that the total infection rate of AMF was closely related to MBC and INV, while the hyphal density was significantly negatively correlated with soil pH and MBN, and significantly positively correlated with AN and MBP (P<0.05). The spore density was significantly positively correlated with MBP, and CAT (P<0.05). Redundancy analysis and regression equations further validated the results of correlation analysis, simultaneously clarifying that MBC is the direct driving factor influencing the colonization and growth of AMF. Research indicates that during the vegetation restoration process on slopes repaired with vegetation concrete, AMF can infect plant roots to form symbiotic associations. Compared to naturally recovered sites and secondary forests, vegetation concrete restoration measures can promote the colonization and growth of AMF. It is recommended that when using vegetation concrete technology to repair slopes, the colonization of AMF be promoted by regulating substrate moisture and nutrients, and microbial management be strengthened at 3 to 5 years post-restoration to optimize ecological benefits. This study provides a theoretical basis and quantitative indicators for the application of mycorrhizal technology in slope engineering.

     

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