Uptake and translocation of phosphate by pho2 mutant and wild-type seedlings of Arabidopsis thaliana |
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Authors: | Bei Dong Zdenko Rengel Emmanuel Delhaize |
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Institution: | (1) Department of Plant Science, Waite Agriculture Research Institute, The University of Adelaide, Glen Osmond, SA 5064, Australia, AU;(2) Soil Science and Plant Nutrition, Faculty of Agriculture, The University of Western Australia, Nedlands, Perth, WA 6907, Australia, AU;(3) Plant Industry, Commonwealth Scientific and Industrial Research Organisation, GPO Box 1600, Canberra, ACT 2601, Australia, AU |
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Abstract: | The pho2 mutant of Arabidopsis thaliana (L.) Heynh. accumulates excessive Pi (inorganic phosphate) concentrations in shoots compared to wild-type plants (E. Delhaize
and P. Randall, 1995, Plant Physiol. 107: 207–213). In this study, a series of experiments was conducted to compare the uptake
and translocation of Pi by pho2 with that of wild-type plants. The pho2 mutants had about a twofold greater Pi uptake rate than wild-type plants under P-sufficient conditions and a greater proportion
of the Pi taken up accumulated in shoots of pho2. When shoots were removed, the uptake rate by roots was found to be similar for both genotypes, suggesting that the greater
Pi uptake by the intact pho2 mutant is due to a greater shoot sink for Pi. Although pho2 mutants could recycle 32Pi from shoots to roots through phloem the proportion of 32Pi translocated to roots was less than half of that found in wild-type plants. When transferred from P-sufficient to P-deficient
solutions, Pi concentrations in pho2 roots had a similar depletion rate to wild-type roots despite pho2 shoots having a fourfold greater Pi concentration than wild-type shoots throughout the experiment. We suggest that the pho2 phenotype could result from a partial defect in Pi transport in the phloem between shoots and roots or from an inability
of shoot cells to regulate internal Pi concentrations.
Received: 20 August 1997 / Accepted: 4 October 1997 |
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Keywords: | :Arabidopsis (pho2 mutant) Mutant (pho2 Arabidopsis) Phosphate (translocation uptake) |
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