PDF(Pubmed)
Abstract：
The presence of polycyclic aromatic hydrocarbons (PAHs) in soil poses a significant global environmental concern, particularly in coastal wetlands. Mangrove ecosystems exhibit enormous potential in environmental purification; however, the underlying mechanisms involved in the degradation of pollutants (e.g., PAHs) remain ambiguous. In the present investigation, a soil pot experiment was conducted with the addition of pyrene to evaluate the effect of radial oxygen loss (ROL) from roots on PAH degradation using three mangrove seedlings (Rhizophora stylosa, Aegiceras corniculatum, and Avicennia marina). The results showed that mangrove plantation can significantly promote the efficiency of pyrene removal. As for the three mangrove species studied, the greatest removal rate (90.75%) was observed in the soils associated with A. marina, followed by A. corniculatum (83.83%) and R. stylosa (77.15%). The higher PAH removal efficiency of A. marina can be partially attributed to its distinctive root anatomical structure, characterized by a thin exodermis and high porosity, which facilitates ROL from the roots. The results from qPCR further demonstrate that ROL is beneficial for promoting the abundance of PAH-ring hydroxylating dioxygenase gene, leading to a higher removal efficiency. Additionally, Rhizobiales, Defferrisomatales, and Ardenticatenales may also play important roles in the process of pyrene degradation. In summary, this study provides evidence for elucidating the mechanism of PAH removal from the perspective of ROL, thereby contributing valuable insights for species selection during mangrove restoration and remediation.
摘要：
土壤中多环芳烃（PAHs）的存在引起了全球重大的环境问题。特别是在沿海湿地。红树林生态系统在环境净化方面表现出巨大潜力；然而，污染物降解所涉及的潜在机制(例如，PAHs)仍然模棱两可。在目前的调查中,使用三个红树林幼苗（Rhizophorastylosa，Aegicerascorniculatum,和Avicenniamarina）。结果表明，红树林人工林能显著提高芘去除效率。至于研究的三种红树林，在与A.marina相关的土壤中观察到最大的去除率(90.75%)，其次是A.corniculatum（83.83％）和R.stylosa（77.15％）。A.marina较高的PAH去除效率可以部分归因于其独特的根部解剖结构，特点是薄的外皮和高孔隙率，这有助于从根部进行ROL。qPCR结果进一步证明ROL有利于促进PAH环羟基双加氧酶基因的丰度,导致更高的去除效率。此外,根瘤菌,Defferrisomatales,和Ardenticatenales也可能在芘降解过程中发挥重要作用。总之,本研究为从ROL的角度阐明PAH的去除机制提供了证据，从而为红树林恢复和修复过程中的物种选择提供有价值的见解。
