Effects of iron complexation and indiscriminate uptake on shoot iron of barley

Bell, Paul F., Edwards, D. G., Asher, C. J. and Kerven, G. L. (2005) Effects of iron complexation and indiscriminate uptake on shoot iron of barley. Journal of Plant Nutrition, 28 6: 963-979. doi:10.1081/PLN-200058887

Author Bell, Paul F.
Edwards, D. G.
Asher, C. J.
Kerven, G. L.
Title Effects of iron complexation and indiscriminate uptake on shoot iron of barley
Journal name Journal of Plant Nutrition   Check publisher's open access policy
ISSN 0190-4167
Publication date 2005
Sub-type Article (original research)
DOI 10.1081/PLN-200058887
Volume 28
Issue 6
Start page 963
End page 979
Total pages 17
Editor Harry A. Mills
Place of publication Philadelphia, PA, United States
Publisher Taylor & Francis
Collection year 2005
Language eng
Subject C1
290600 Chemical Engineering
670799 Other
Abstract The free-ion model (FIM) describes iron ( Fe) uptake by barley [ Hordeum vulgare ( L.) 'Grammett'] as being controlled by the activity of the buffered, free, uncomplexed Fe3+ in solution. Chelators' effect on Fe uptake by barley was evaluated and the rate of exchange of Fe between chelators was examined. Barley was grown for two weeks in a low-Fe nutrient solution and transferred to solutions varying in Fe and chelators for 6 h assays. Shoot Fe-59 was higher in barley grown in citrate (7743 and 1928 Fe-59 Bq g(-1)) than in NTA(3220 and 1113 Fe-59 Bq g(-1); P = 0.045) despite similar free-Fe3+ activities. A comparison of Fe uptake by barley from solutions with pFe(3+) activities of 17.1 and 24.6 showed < 5% was from indiscriminate apoplastic-flow uptake (3250 Fe-59 Bq g(-1) vs. 160 Fe-59 Bq g(-1)). Using nutrient solutions from the barley studies but without plants, Fe exchange between chelators and a simulant for the barley phytosiderophore occurred within hours ( for NTA and citrate), or days ( EDTA and HEDTA). Results were similar between the barley and Fe-exchange experiments for the two nutrient-solution treatments where the same Fe3+ activities but different total-Fe concentrations were used: the higher total-Fe treatment resulted in six-fold higher shoot Fe-59, while in the Fe-exchange study that treatment had six-fold more Fe bound to the phytosiderophore simulant after 2 d. Results indicated deviations from the FIM were not explained by indiscriminate-flow uptake, and that sluggish Fe-exchange reactions between chelate and phytosiderophoresimulant, not FIM guidelines, may be more important in explaining Fe uptake from synthetic chelates by Fe-deficient barley.
Keyword Plant Sciences
Free-ion Model
Solution Culture
Acid-ferric Complex
Mugineic Acid
Citrate Transport
Q-Index Code C1
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2006 Higher Education Research Data Collection
School of Agriculture and Food Sciences
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Citation counts: TR Web of Science Citation Count  Cited 2 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 15 Aug 2007, 07:49:09 EST