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- Title
Evidence for the mechanisms of zinc uptake by rice using isotope fractionation.
- Authors
ARNOLD, TIM; KIRK, GUY J. D.; WISSUWA, MATTHIAS; FREI, MICHAEL; FANG-JIE ZHAO; MASON, THOMAS F. D.; WEISS, DOMINIK J.
- Abstract
In an earlier study, we found that rice ( Oryza sativa) grown in nutrient solution well-supplied with Zn preferentially took up light 64Zn over 66Zn, 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.
- Subjects
RICE; PLANT-soil relationships; BIOLOGICAL transport; GENETIC polymorphisms; GENETIC research
- Publication
Plant, Cell & Environment, 2010, Vol 33, Issue 3, p370
- ISSN
0140-7791
- Publication type
Article
- DOI
10.1111/j.1365-3040.2009.02085.x