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文摘
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铁是地球上丰度排第四的元素,其地球化学行为作为稻田体系循环的重要组成部分而具有重大意义。铁也是植物维持正常生命活动的必需微量元素之一,参与众多生物代谢过程。十几年来,铁同位素方法在表生地球化学的应用得到了广泛关注,铁同位素方法已被广泛地用来追踪异化铁还原、亚铁的生物和非生物氧化以及吸附、沉淀等铁的生物地球化学过程。文章综述了水稻土铁同位素分馏特征及影响因素,以及水稻中铁吸收转运的分子生理机制和铁同位素分馏特征和机制。水稻土在发育过程中缺损轻铁,且不同的发育过程导致土壤中铁形态、价态的改变而会形成特有的分馏特征。植物铁同位素分馏效应的研究表明,植物吸收铁的机制不同,产生的铁同位素分馏程度呈现出显著的差异。当植物以机理I的方式,即通过将三价铁还原为二价铁再吸收铁时,植物优先吸收轻的铁同位素,且铁同位素在植物内部的分馏程度较大[–0.13‰-(–1.64‰)]。当植物通过机理II的方式,即通过螯合三价铁,再吸收至植物体内的过程,植物优先吸收重的铁同位素,且铁同位素的分馏程度较小(–0.11‰-0.17‰)。水稻铁同位素组成不同于典型的机理II植物,水稻富集轻铁,且铁同位素在水稻植株中存在较大分馏。这可能是因为水稻在根吸收铁的过程中同时采用机理I和机理II途径,且铁在水稻内的转运过程、配体改变及价态改变等都会导致铁的同位素分馏。铁同位素方法在揭示水稻对铁元素的吸收机制方面表现出巨大应用潜力。文章还分别对如何将铁同位素方法结合土壤-水稻体系的土壤发育背景,以及通过制样方法的改进、结合质量平衡计算、动力学分馏、综合多个表征手段等方式来解释水稻铁同位素机制进行了讨论和展望。 |
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其他语种文摘
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Iron is the fourth abundant element on the earth,and its geochemical behavior is of great significance as an important part of the element circulation of paddy field system.Iron is also one of the essential trace elements in the normal life process of plants,and participates in many biological metabolic processes.Over the past decade,the application of iron isotope method in supergene geochemistry has received extensive attention.Iron isotope method has been widely used to investigate the biogeochemical processes of iron,such as dissimilatory iron reduction,ferrous and abiotic oxidation of ferrous iron,and adsorption,precipitation and other processes.In this paper,the characteristics and influencing factors of iron isotope fractionation in paddy soils,the molecular physiological mechanism of iron absorption and transport in rice and the characteristics and mechanisms of iron isotope fractionation are reviewed.Paddy soils are deficient in light iron during development,and different developmental processes lead to changes in iron forms and valences in the soils,thus forming unique fractionation characteristics.In previous study of iron isotope fractionation during soil-plant systems,iron uptake in plants with different mechanisms for iron uptake showed distinguish magnitude and behavior of iron isotope fractionation.In the plant of Strategy I,Fe(III) is reduced into Fe(II) and it is uptaken into the plant.The Fe isotope composition becomes light and magnitude of fractionation is large inside the plant [–0.13‰ – (–1.64‰)].In the plant of Strategy II,Fe(III) is transported into the plant by process of chelation.The Fe isotope composition becomes heavy and magnitude of fractionation is small inside the plant (–0.11‰–0.17‰).The iron isotope composition of rice is different from that of typical mechanism II plants.Rice is rich in light iron,and magnitude of Fe isotope fractionation is large inside the rice plants.This may be due to the simultaneous use of strategy I and strategy II pathways during iron uptake process by rice roots,and iron transport in rice,ligand changes and valence changes will lead to iron isotope fractionation.Iron isotope method shows great potential in revealing the mechanism of iron transport in soil-rice systems.This review also discussed and prospected how to combine the iron isotope method with the soil development background of the soil-rice system,and how to explain the iron isotope mechanism of rice by improving the sample preparation method,combining with mass balance calculation,dynamic fractionation,and multiple characterization methods. |
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来源
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生态环境学报
,2019,28(6):1251-1260 【核心库】
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DOI
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10.16258/j.cnki.1674-5906.2019.06.022
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关键词
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稻田铁
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机理Ⅰ
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机理Ⅱ
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铁同位素
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地址
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1.
广东省生态环境技术研究所, 广东, 广州, 510650
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中国科学院广州地球化学研究所, 广东, 广州, 510640
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中国科学院大学, 北京, 100039
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语种
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中文 |
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文献类型
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综述型 |
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ISSN
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1674-5906 |
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学科
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农业基础科学;环境科学基础理论 |
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基金
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国家自然科学基金
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文献收藏号
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CSCD:6533709
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