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Evidence for the mechanisms of zinc uptake by rice using isotope fractionation.
- Source :
- Plant, Cell & Environment; Mar2010, Vol. 33 Issue 3, p370-381, 12p, 3 Diagrams, 5 Charts, 3 Graphs
- Publication Year :
- 2010
-
Abstract
- In an earlier study, we found that rice ( Oryza sativa) grown in nutrient solution well-supplied with Zn preferentially took up light <superscript>64</superscript>Zn over <superscript>66</superscript>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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01407791
- Volume :
- 33
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Plant, Cell & Environment
- Publication Type :
- Academic Journal
- Accession number :
- 47978817
- Full Text :
- https://doi.org/10.1111/j.1365-3040.2009.02085.x