Römheld, Volker and Marschner, H. (1983) Mechanism of iron uptake by peanut plants. I. FeIII reduction, chelate splitting, and release of phenolics. Plant Physiology, 71 (4). pp. 949-954.
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Abstract
Iron deficiency in peanuts (Arachis hypogeae L.) caused an increase in release of caffeic acid, a higher rate of FeIII reduction, and increased rates of both FeIII chelate splitting and iron uptake. Experiments on FeIII reduction by phenolics (in vitro experiments) and by roots of Fe-deficient peanuts exclude the direct involvement of released phenolics in FeIII reduction by roots: FeIII reduction by phenolics had a pH optimum higher than 8.0 and was strongly dependent on the concentration and the stability of the supplied FeIII chelates. In contrast, FeIII reduction by roots of Fe-deficient peanuts had a pH optimum of about 5.0 and was less dependent on the stability of the supplied FeIII chelates. Furthermore, the observed release of phenolics into nutrient solution would have to be at least 200 times higher to attain the reduction rates of roots of Fe-deficient peanuts. The results of these experiments support the idea of an enzymic reduction of FeIII on the plasmalemma of cortical cells of roots.ADDITIONAL ABSTRACT:Iron deficiency in groundnuts caused an increase in the release of caffeic acid, a higher rate of FeIII reduction and increased rates of both FeIII chelate splitting and Fe uptake. Reduction of FeIII in vitro by phenolics had a pH opt. >8.0 and was strongly dependent on the level and the stability of the supplied FeIII chelates, whereas FeIII reduction by roots of Fe-deficient groundnuts had a pH opt. of about 5.0 and was less dependent on the stability of the chelates. The observed release of phenolics into nutrient sol. was insufficient to account for the reduction rates of roots of Fe-deficient plants. The results exclude the direct involvement of released reducing substances by roots and support the hypothesis of an enzymic reduction of FeIII on the plasmalemma of cortical cells of roots.
| Item Type: | Article |
|---|---|
| Additional Information: | SNNigam Collection |
| Author Affiliation: | Institut für Pflanzenernährung, Universität Hohenheim, Postfach 700562, D-7000 Stuttgart 70, German Federal Republic. |
| Subjects: | Soil Science and Microbiology Crop Improvement Plant Physiology and Biochemistry > Plant Physiology |
| Divisions: | Groundnut |
| Depositing User: | Mr Balakrishna Garadasu |
| Date Deposited: | 03 Apr 2013 13:36 |
| Last Modified: | 03 Apr 2013 13:36 |
| Official URL: | http://dx.doi.org/10.1104/pp.71.4.949 |
| URI: | http://eprints.icrisat.ac.in/id/eprint/10134 |
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