Iron and zinc isotope fractionation during uptake and translocation in rice (Oryza sativa) grown in oxic and anoxic soils
Iron and zinc isotope fractionation during uptake and translocation in rice (Oryza sativa) grown in oxic and anoxic soils
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DOI：
10.1016/j.crte.2015.05.005
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发表时间：
2015-11-01
影响因子：
1.4
通讯作者：
Weiss, Dominik J.
中科院分区：
文献类型：
--
作者：
Arnold, Tim;Markovic, Tamara;Weiss, Dominik J.
稳定同位素分馏技术是研究植物体内金属吸收和转运的一种强有力的新技术。这一发展的基础是彻底了解在不同环境条件下导致同位素分馏的过程。在这项研究中，我们研究了在温室条件下厌氧和好氧土壤中水稻生长到成熟期的锌和铁的同位素分馏。在水稻植株中锌同位素含量较轻的厌氧土壤中，土壤与地上部物质之间的锌同位素分配率在好氧土壤中可以忽略不计，但在厌氧土壤中显著。观测到的分级范围与之前测定的水培溶液和淹水土壤中水稻中锌的分级范围一致，并强调了吸收不同化学形态锌的影响，最有可能的是游离锌和有机络合锌。在好氧和厌氧土壤中生长的水稻籽粒中的锌同位素比地上植株的其余部分要轻。这表明，在谷物装载过程中和在植物内部的转运过程中，发生了重要的生化和/或生物物理过程。在颗粒中观察到的同位素分馏与单向受控的从芽到颗粒的传输是一致的，分馏因子α接近0.9994。与好氧和厌氧土壤中的土壤或渗滤液相比，地上部和籽粒中的铁同位素表现出较轻的同位素特征。同位素分馏的负方向与Fe在吸收和转移过程中可能发生的氧化还原状态的变化一致。锌和铁在水稻地上部和籽粒物质之间的同位素分馏模式不同，说明这两种关键微量元素在水稻体内的运转和装粒过程中起着不同的作用机制。(C)2015年科学院。爱思唯尔·马森公司出版。版权所有。
Stable isotope fractionation is emerging quickly as a powerful novel technique to study metal uptake and translocation in plants. Fundamental to this development is a thorough understanding of the processes that lead to isotope fractionation under differing environmental conditions. In this study, we investigated Zn and Fe isotope fractionation in rice grown to maturity in anaerobic and aerobic soils under greenhouse conditions. The overall Zn isotope fractionation between the soil and above ground plant material was negligible in aerobic soil but significant in anaerobic soil with isotopically lighter Zn in the rice plant. The observed range of fractionation is in line with previously determined fractionations of Zn in rice grown in hydroponic solutions and submerged soils and emphasizes the effect of taking up different chemical forms of Zn, most likely free and organically complexed Zn. The Zn in the grain was isotopically lighter than in the rest of the above ground plant in rice grown in aerobic and anaerobic soils alike. This suggests that in the course of the grain loading and during the translocation within the plant important biochemical and/or biophysical processes occur. The isotope fractionation observed in the grains would be consistent with an unidirectional controlled transport from shoot to grain with a fractionation factor of alpha approximate to 0.9994. Iron isotopes showed an isotopic lighter signature in shoot and grain compared to the bulk soil or the leachate in aerobic and anaerobic soils alike. The negative direction of isotopic fractionation is consistent with possible changes in the redox state of Fe occurring during the uptake and translocation processes. The isotope fractionation pattern between shoots and grain material are different for Zn and Fe which finally suggests that different mechanisms operate during translocation and grain-loading in rice for these two key micronutrients. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.