外源铁作用下的水稻根系分泌物对汞甲基化的影响
Effect of Rice Root Exudates on Mercury Methylation by Exogenous Iron
钟顺清 1刘双 1张钰1
作者信息
- 1. 衡阳师范学院 地理与旅游学院,湖南 衡阳 421002
- 折叠
摘要
根际区甲基汞(MeHg)含量高低直接影响水稻吸收积累甲基汞量,在外源铁作用下的水稻根系分泌物如何影响根际汞的甲基化值得深入探讨.通过溶液培养实验,向溶液中添加铁诱导水稻根表产生铁氧化物,然后收集水稻根系分泌物,将其添加至人为汞污染土壤中培养,研究外源铁作用下的水稻根系分泌物对汞甲基化的影响.结果表明:水稻根系分泌物(FMW)和铁诱导后水稻根系分泌物(FMWFe)处理土壤中MeHg平均含量分别比对照(DDW)高35.73%和12.04%.FMWFe处理下溶解态和可交换态(F1)、特殊吸附态(F2)以及有机结合态汞比例低于FMW处理,FMWFe处理下土壤有机质(SOM)和微生物多样性均低于FMW处理,Pearson相关性分析表明,SOM和生物利用态汞(F1和F2)比例的降低是外源铁抑制水稻根系分泌物对土壤汞甲基化的重要因素.这研究结果为揭示外源铁影响水稻根际汞转化具有重要的意义.
Abstract
The content of methylmercury(MeHg)in rhizosphere directly affects the amount of methylmercury absorbed and accumulated by rice,and it is deserved further discussion that the root exudates of rice affect the methylation of mercury in rhizosphere by the exogenous iron.By the solution culture experiment,iron oxide on the rice root surface was formed by the addition of iron in the solution,and the rice root exudates were collected and added to the mercury-contaminated soil.The MeHg content,microorganisms,mercury speciation,pH value and organic matter were determined to study the effect of rice root exudates on mercury methylation by the exogenous iron.The results showed that the average content of MeHg in soil treated with rice root exudates(FMW)and iron-induced rice root exudates(FMWFe)was 35.73%and 12.04%higher than that of control(DDW),respectively.The proportion of dissolved and exchangeable(F1),specially adsorbed(F2)and organically bound mercury under FMWFe treatment was lower than that under FMW treatment,and the soil organic matter(SOM)and microbial diversity under FMWFe treatment were lower than that under FMW treatment.Person correlation analysis showed that the reduction of the proportion of SOM and bioavailable mercury(F1 and F2)was the main factor that exogenous iron inhibited the methylation of mercury in soil by rice root exudates.The results of this study are of great significance to reveal the influence of exogenous iron on the transformation of mercury in rice rhizosphere.
关键词
根系分泌物/水稻/铁/甲基汞/微生物Key words
root exudates/rice/iron/methyl mercury/microorganism引用本文复制引用
基金项目
国家自然科学基金项目(42077297)
湖南省研究生科研创新项目(CX20221270)
出版年
2024
NETL
NSTL
万方数据