Reactive oxygen species (ROS) are recognised as pivotal biogeochemical process drivers. However, the factors influencing ROS production in the rhizosphere and their role in pollutant transformation remain elusive. We investigated ROS with a focus on spatiotemporal variations in superoxide radicals (O), hydrogen peroxide (HO), and hydroxyl radicals (OH) in the rhizosphere of maize during root development, and elucidated the impact of environmental conditions on ROS production. visualisation by fluorescence imaging showed that ROS hotspots gradually shifted from seminal to lateral roots during maize growth, indicating that newly developed roots are the major contributors to ROS production. The three types of ROS contents changed with root growth, suggesting that root development regulates ROS production. The ROS contents reached a maximum at 25 °C and 45% maximum field capacity. Both ambient temperature and soil moisture indirectly influenced ROS production by regulating the release of root exudates to induce changes in water-soluble phenols and dissolved organic carbon (DOC). In contrast, ROS content gradually increased with oxygen availability, which directly mediated ROS generation by acting as a precursor. More interestingly, the presence of polycyclic aromatic hydrocarbons (PAHs) significantly enhanced ROS generation, which further promoted PAH removal with a contribution of 31.4–43.3%. These findings provide new insights into the occurrence, distribution, and environmental effects of ROS in the rhizosphere.

中文翻译：

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关于影响根际活性氧产生的因素及其在多环芳烃转化中的作用的新见解


活性氧（ROS）被认为是关键的生物地球化学过程驱动因素。然而，影响根际ROS产生的因素及其在污染物转化中的作用仍然难以捉摸。我们研究了 ROS，重点关注根发育过程中玉米根际超氧自由基 (O)、过氧化氢 (H2O) 和羟基自由基 (OH) 的时空变化，并阐明了环境条件对 ROS 产生的影响。荧光成像可视化显示，在玉米生长过程中，ROS热点逐渐从种子根转移到侧根，这表明新发育的根是ROS产生的主要贡献者。三种类型的ROS含量随着根的生长而变化，表明根的发育调节ROS的产生。 ROS含量在25℃和最大田间持水量的45%时达到最大值。环境温度和土壤湿度通过调节根系分泌物的释放来诱导水溶性酚和溶解有机碳（DOC）的变化，间接影响ROS的产生。相比之下，ROS 含量随着氧气的可用性而逐渐增加，这通过充当前体直接介导 ROS 的生成。更有趣的是，多环芳烃（PAH）的存在显着增强了ROS的产生，进一步促进了PAH的去除，贡献率达到31.4-43.3%。这些发现为根际ROS的发生、分布和环境影响提供了新的见解。