O2 distribution and dynamics in the rhizosphere of Phragmites australis, and implications for nutrient removal in sediments
O2 distribution and dynamics in the rhizosphere of Phragmites australis, and implications for nutrient removal in sediments
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芦苇根际氧气分布和动态及其对沉积物中养分去除的影响
DOI：
10.1016/j.envpol.2021.117193
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发表时间：
2021
影响因子：
8.9
通讯作者：
Yan Wang
中科院分区：
文献类型：
--
作者：
Cai Li;Shiming Ding;Xin Ma;Musong Chen;Zhilin Zhong;Yi Zhang;Mingyi Ren;Min Zhang;Liyuan Yang;Nan Rong;Yan Wang
根引发的芦荟幼体根际O2分布的微尺度变化对于沉积物中营养物质的去除是重要的。本文研究了根际有机磷(OFP)的微尺度O2动态及可溶性活性磷(SRP)和氨氮(NH4+)的小尺度变化。分别使用平面光电二极管和高分辨率透析仪(HR-Peeper)研究澳大利亚。结果表明，根O2渗漏分布随根系生长阶段的不同而变化较大，渗漏部位逐渐从整个出苗主根向主根尖转移，继而使出苗侧根发生移位。根际O2浓度随着光照强度和上覆水中O2浓度的增加而增加。侧根持续释放O2导致侧根表面形成铁斑，从而通过吸附根际铁斑来降低P的移动性。好氧-缺氧根区的振荡通过厌氧氨氧化、异养反硝化和硝化作用促进脱氮。这项从微观尺度上的工作表明，O2浓度是根际的时空变化，它对沉积物中养分的去除具有重要的作用。
Root-triggered microscale variations in O2distribution in the rhizosphere of youngPhragmites australisare important for nutrient removal in sediments. In this study, the micro-scale O2dynamics and the small-scale changes of soluble reactive phosphorus (SRP) and ammonium (NH4+) in the rhizosphere ofP. australiswere investigated using planar optodes and high-resolution dialysis (HR-Peeper), respectively. Results suggested that root O2leakage has a highly variable distribution depending on the stage of root growth, the site of O2leakage gradually shift from the entire emerging main roots to the main root tip and subsequently shifted the emerging lateral roots. The O2concentration increased in the rhizosphere with increasing light intensity and O2levels in the overlying water. Continuous O2release from the lateral roots causes the formation of iron plaque on the surface of lateral roots, which reduce the mobility of P by adsorption of iron plaque in the rhizosphere. The oscillation of oxic-anoxic root zones improves nitrogen removal through the processes of anammox, heterotrophic denitrification and nitrification. This work from the micro-scale demonstrates that the O2concentration is the spatio-temporal variations in the rhizosphere, and it presents an important role for nutrient removal in sediments.