Evidence for the mechanisms of zinc uptake by rice using isotope fractionation
| Autor: | Matthias Wissuwa, Tim Arnold, Michael Frei, Guy J. D. Kirk, Dominik J. Weiss, Fang-Jie Zhao, T. F. D. Mason |
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| Rok vydání: | 2010 |
| Předmět: |
Oryza sativa
Genotype Physiology Chemistry Stable isotope ratio Plant Sciences chemistry.chemical_element food and beverages Oryza Plant Science Zinc Fractionation engineering.material Models Theoretical Soil Isotope fractionation Agronomy Environmental chemistry Kinetic fractionation engineering Poaceae Zinc Isotopes Fertilizer Plant Shoots |
| Popis: | In an earlier study, we found that rice (Oryza sativa) grown in nutrient solution well-supplied with Zn preferentially took up light (64)Zn over (66)Zn, probably as a result of kinetic fractionation in membrane transport processes. Here, we measure isotope fractionation by rice in a submerged Zn-deficient soil with and without Zn fertilizer. We grew the same genotype as in the nutrient solution study plus low-Zn tolerant and intolerant lines from a recombinant inbred population. In contrast to the nutrient solution, in soil with Zn fertilizer we found little or heavy isotopic enrichment in the plants relative to plant-available Zn in the soil, and in soil without Zn fertilizer we found consistently heavy enrichment, particularly in the low-Zn tolerant line. These observations are only explicable by complexation of Zn by a complexing agent released from the roots and uptake of the complexed Zn by specific root transporters. We show with a mathematical model that, for realistic rates of secretion of the phytosiderophore deoxymugineic acid (DMA) by rice, and realistic parameters for the Zn-solubilizing effect of DMA in soil, solubilization and uptake by this mechanism is necessary and sufficient to account for the measured Zn uptake and the differences between genotypes. |
| Databáze: | OpenAIRE |
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