石灰性水稻土中硝酸盐依赖型与光合型亚铁氧化过程  

Nitrate-Dependent and Photosynthetic Fe(II)Oxidation Processes in a Calcareous Paddy Soil

作　　者：陈志怀 王旭刚[1,2] 孙丽蓉 董乐恒[1] 郭大勇 石兆勇[1,3] CHEN Zhihuai;WANG Xugang;SUN Lirong;DONG Leheng;GUO Dayong;SHI Zhaoyong(Agricultural College,Henan University of Science and Technology,Luoyang,Henan 471000,China;Luoyang Key Laboratory of PlantNutrition and Environmental Ecology,Luoyang,Henan 471000,China;Luoyang Key Laboratory of Symbiotic Microbes and GreenDevelopment,Luoyang,Henan 471000,China)

机构地区：[1]河南科技大学农学院,河南洛阳471000 [2]洛阳市植物营养与环境生态重点实验室,河南洛阳471000 [3]洛阳市共生微生物与绿色发展重点实验室,河南洛阳471000

出　　处：《土壤学报》2023年第1期127-137,共11页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(U1904121,41601309)资助。

摘　　要：厌氧条件下土壤中铁氧化还原过程与土壤氮循环关系密切,且硝酸盐依赖型亚铁氧化(nitrate-dependent ferrous oxidation,NDFO)和光合型亚铁氧化(photosynthetic ferrous oxidation,PFO)是亚铁氧化的两个重要的生物途径,然而目前关于石灰性水稻土中NDFO与PFO之间的关系仍不明晰。以采自黄河中下游地区河南省孟津县的水稻土为样品,设置培养前添加和培养过程中添加10 mmol·L^(–1)的硝酸根离子/铵离子(NO_(3)^(-)/NH_(4)^(+))的恒温厌氧泥浆培养试验,通过监测泥浆中Fe(Ⅱ)、O_(2)、NO_(3)^(-)和亚硝酸根离子(NO_(2)^(-))的动态变化与培养后的NH_(4)^(+)含量探究了NO_(3)^(-)在石灰性水稻土Fe(Ⅱ)氧化过程的作用及其与光合型亚铁氧化的关系。结果表明:避光条件下石灰性水稻土中存在NDFO,但产生的Fe(Ⅲ)可在NO_(3)^(-)消耗殆尽时被再次还原而掩盖Fe(Ⅱ)氧化现象。光照条件下NDFO和PFO可同时存在,PFO可致1.99 mg·g^(–1) Fe(Ⅱ)氧化,NO_(3)^(-)的加入可使Fe(Ⅱ)氧化量增加0.57 mg·g^(–1)。光照可抑制NO_(3)^(-)的还原而抑制NDFO。研究结果对于进一步理解湿地铁的氧化还原及其耦合的氮素转化过程有重要意义。【Objective】Iron redox processes under anaerobic conditions are closely correlated to nitrogen cycling in soils.Both nitrate-dependent ferrous oxidation(NDFO)and photosynthetic ferrous oxidation(PFO)are crucial pathways of biological ferrous iron oxidation.However,whether NDFO occurs in calcareous paddy soils and its relation to PFO is still ambiguous.【Method】Soil samples were collected from Mengjin County,Henan Province,within the middle and lower reaches of the Yellow River.The soil samples were made into slurries using 10 mmol·L^(-1)3 NO-/4 NH+solution or water at the very beginning.Then the slurries were anaerobically incubated under darkness or illuminated.On the 7th day of the incubation,we injected 0.5 mL 70 mmol·L^(-1)3 NO-or 4 NH+into a part of those slurries made with water to adjust their external 3 NO-or 4 NH+content to 10 mmol L^(-1).To assess the iron reduction,and ferrous oxidation,Fe(II)in the slurries was measured dynamically using the phenanthroline colorimetric method.To evaluate the nitrogen transformation,3 NO-and 2 NO-were analyzed dynamically using an ion chromatograph equipped with an electrical conductivity detector,and 4 NH+was measured after the incubation by 1 mol·L^(-1) KCl extraction-Kjeldahl method.To fractionate the PFO,O2 in the headspaces was determined dynamically using a portable fiber-optic trace oxygen meter.【Result】The results showed that,though no apparent ferrous oxidation was observed,iron reduction rate decreased by 0.28 mg·g^(-1)·d^(-1) and 0.33 mg·g^(-1)·d^(-1).Also,the iron reduction rate constant was decreased by 0.15 d^(-1),and 0.17 d^(-1) in slurries under darkness with 3 NO-or 4 NH+amended at the very beginning.Ferrous iron was oxidized by 2.21 mg·g^(-1) and 0.68 mg·g^(-1) in slurries with 3 NO-or 4 NH+injected on the 7th day of the dark incubation and by 1.99 mg·g^(-1) in slurries incubated under light.In addition,Fe(II)in the slurries was negatively correlated to O2 in the headspace.Importantly,the reduction of 3 NO-to 4 NH+occurred in the s

关 键 词：水稻土 亚铁氧化 光合产氧 硝酸盐还原 氮素转化 

分 类 号：S153.4[农业科学—土壤学]