Evidence for the mechanisms of zinc uptake by rice using isotope fractionation

A - Papers appearing in refereed journals

Arnold, T., Kirk, G. J. D., Wissuwa, M., Frei, M., Zhao, F-J., Mason, T. F. D. and Weiss, D. J. 2010. Evidence for the mechanisms of zinc uptake by rice using isotope fractionation. Plant, Cell & Environment. 33 (3), pp. 370-381.

AuthorsArnold, T., Kirk, G. J. D., Wissuwa, M., Frei, M., Zhao, F-J., Mason, T. F. D. and Weiss, D. 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.

KeywordsPlant Sciences
Year of Publication2010
JournalPlant, Cell & Environment
Journal citation33 (3), pp. 370-381
Digital Object Identifier (DOI)doi:10.1111/j.1365-3040.2009.02085.x
PubMed ID19929899
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeSEF
ISSN01407791
PublisherWiley

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