The benefits of plant–microbe interactions have been exploited extensively for nutrient removal. Radial oxygen loss in aquatic macrophytes potentially promotes nitrification and accelerates nitrogen removal through coupled nitrification–denitrification process. Nitrification is likely the limiting activity for an effective nitrogen removal in wetlands. In this work, we have quantified the effect of radial oxygen losses in Typha angustifolia plants in environments of contrasting salinities, including a temporary lagoon, a constructed wetland, and a river estuary. In all sites, radial oxygen diffusion occurred mainly at a narrow band, from 1 to 5 cm from the root tip, and were almost absent at the tip and basal sections of the root (> 5 cm). Root sections with active oxygen diffusion tended to show higher bacterial and archaeal densities in the rhizoplane according to 16S rRNA gene abundance data, except at higher salinities. Archaeal amoA /bacterial amoA gene ratios were highly variable among sites. Archaeal nitrifiers were only favoured over bacteria on the root surface of Typha collected from the constructed wetland. Collectively, radial oxygen loss had little effect on the nitrifying microbial community at the smaller scale (differences according to root-section), and observed differences were more likely related to prevailing physicochemical conditions of the studied environments or to long-term effects of the root microenvironment (root vs sediment comparisons).

植物-微生物相互作用的好处已被广泛用于去除养分。水生大型植物中的径向氧损失可能会促进硝化作用，并通过耦合硝化 - 反硝化过程加速脱氮。硝化作用可能是湿地有效脱氮的限制性活动。在这项工作中，我们量化了香蒲中径向氧损失的影响不同盐度环境中的植物，包括临时泻湖、人工湿地和河口。在所有部位，径向氧扩散主要发生在距离根尖 1 至 5 厘米的窄带上，而在根尖和根基部（> 5 厘米）几乎不存在。根据 16S rRNA 基因丰度数据，具有活性氧扩散的根部分往往在根平面中显示出更高的细菌和古菌密度，但盐度较高的情况除外。古菌amoA / 细菌amoA基因比率在不同位点之间变化很大。古菌硝化菌只比香蒲根表面的细菌更受青睐从人工湿地采集。总体而言，径向氧损失对较小规模的硝化微生物群落几乎没有影响（根据根截面的差异），观察到的差异更可能与研究环境的主要物理化学条件或根的长期影响有关微环境（根与沉积物的比较）。