钝化土壤根际pH值和O_(2)精细变化特征研究  

Refined imaging of pH and O2 across the passivated soil-root micro-interfaces

作　　者：任静华[1] 范健[1] 孙宇 廖启林[1] 许伟伟[1] 刘玲[1] 韩超[2] 顾雪元[3] REN Jing-hua;FAN Jian;SUN Yu;LIAO Qi-lin;XU Wei-wei;LIU Ling;HAN Chao;GU Xue-yuan(Technology Innovation Center for Ecological Monitoring&Restoration Project on Land(arable),Ministry of Natural Resources,Geological Survey of Jiangsu Province,Nanjing 210018,China;State Key Laboratory of Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China;State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210023,China)

机构地区：[1]自然资源部(国土)耕地生态监测与修复工程技术创新中心,江苏省地质调查研究院,江苏南京210018 [2]湖泊与环境国家重点实验室,中国科学院南京地理与湖泊研究所,江苏南京210008 [3]污染控制与资源化利用国家重点实验室,南京大学环境学院,江苏南京210023

出　　处：《中国环境科学》2023年第4期1782-1790,共9页China Environmental Science

基　　金：国家自然科学基金资助项目(41907141);江苏省自然科学基金资助项目(BK20171075);污染控制与资源化研究国家重点实验室开放基金资助项目(PCRRF20034)。

摘　　要：采用自主构建的平面光极技术(PO),以凹凸棒石黏土钝化土壤-根系微界面为研究对象,精细刻画土壤-根系微界面pH值和O_(2)的同步变化特征.研究结果首次直观和定量证实,不同钝化土壤剖面pH值和O_(2)在毫米尺度呈高度的空间异质性并具有显著的差异(P<0.01).添加凹凸棒石黏土使土壤pH值升高但对O_(2)微环境影响不显著,钝化土壤-根系2~5mm范围内pH值降低0.31~0.87个单位,而O_(2)含量增加至58.56~82.01μmol/L,靠近根基部位为根系分泌有机酸和O_(2)的热点区域,与CK相比,中、高Cd污染钝化土壤-根系微界面酸化和释氧能力较强,在一定程度上会促进钝化Cd的再活化和水稻根系的吸收.Herein two self-established planar optode methods(PO)were successfully deployed to in situ,high-resolution investigate the fine-scale and simultaneous variations of micro-environmental conditions e.g.pH and O_(2) across the passivated soil-root interfaces.For the first time,our results quantitatively and directly revealed the high degrees of spatiotemporal heterogeneity of pH and O_(2) throughout the rhizosphere at the sub-mm scale.Significant differences(P<0.01)among three Cd treatments were observed.The addition of the attapulgite clays significant elevated the pH micro-environemnts,but had slight effects on the micro-distributions of O_(2) within the soil profiles.There was a visible and distinct range of 2~5mm surrounding the rice roots where pH values were generally decreased by 0.31~0.87 and O_(2) concentrations were increased to 58.56~82.01μmol/L.Notably higher rhizosphere acidification and O_(2) leakage always occurred locally around the basal roots.The higher abilities of rhizosphere acidification and O_(2) leakage within the passivated soil-root micro interfaces would potentially promote the reactivation and root uptake of passivated Cd.

关 键 词：平面光电极 CD 土壤 水稻 微界面 

分 类 号：X53[环境科学与工程—环境工程]