Abstract
We hypothesized that the resistance of Hawkeye (HA) soybean (Glycine max L.) to iron-deficiency induced chlorosis (IDC) is correlated to an ability to accumulate a large pool of extracellular-root iron which can be mobilized to shoots as the plants become iron deficient. Iron in the root apoplast was assayed after efflux from the roots of intact plants in nutrient solution treated with sodium dithionite added under anaerobic conditions. Young seedlings of HA soybean accumulated a significantly larger amount of extracellular iron in their roots than did either IDC-susceptible PI-54619 (PI) soybean or IDC-resistant IS-8001 (IS) sunflower (Helianthus annus L.). Concurrently, HA soybean had much higher concentrations of iron in their shoots than either PI soybean or IS sunflower. The concentration of iron in the root apoplast and in shoots of HA soybean decreased sharply within days after the first measurements of extracellular root iron were made, in both +Fe and −Fe treatments. The accumulation of short-term iron reserves in the root apoplast and translocation of iron in large quantities to the shoot may be important characteristics of IDC resistance in soybeans.
Full text
PDF![17](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/943c/1062241/66ace756ab10/plntphys00674-0031.png)
![18](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/943c/1062241/695128cd3a9a/plntphys00674-0032.png)
![19](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/943c/1062241/aa36e8b5bcf2/plntphys00674-0033.png)
![20](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/943c/1062241/3657602f8475/plntphys00674-0034.png)
![21](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/943c/1062241/9307876cf3f3/plntphys00674-0035.png)
![22](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/943c/1062241/ca0f0d9cd96c/plntphys00674-0036.png)
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bienfait H. F., van den Briel W., Mesland-Mul N. T. Free space iron pools in roots: generation and mobilization. Plant Physiol. 1985 Jul;78(3):596–600. doi: 10.1104/pp.78.3.596. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cakmak I., van de Wetering D. A., Marschner H., Bienfait H. F. Involvement of superoxide radical in extracellular ferric reduction by iron-deficient bean roots. Plant Physiol. 1987 Sep;85(1):310–314. doi: 10.1104/pp.85.1.310. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chaney R. L., Brown J. C., Tiffin L. O. Obligatory reduction of ferric chelates in iron uptake by soybeans. Plant Physiol. 1972 Aug;50(2):208–213. doi: 10.1104/pp.50.2.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clark R. B., Tiffin L. O., Brown J. C. Organic acids and iron translocation in maize genotypes. Plant Physiol. 1973 Aug;52(2):147–150. doi: 10.1104/pp.52.2.147. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clarkson D. T., Sanderson J. Sites of absorption and translocation of iron in barley roots: tracer and microautoradiographic studies. Plant Physiol. 1978 May;61(5):731–736. doi: 10.1104/pp.61.5.731. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Römheld V., Marschner H. Mechanism of iron uptake by peanut plants : I. Fe reduction, chelate splitting, and release of phenolics. Plant Physiol. 1983 Apr;71(4):949–954. doi: 10.1104/pp.71.4.949. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sijmons P. C., Lanfermeijer F. C., de Boer A. H., Prins H. B., Bienfait H. F. Depolarization of Cell Membrane Potential during Trans-Plasma Membrane Electron Transfer to Extracellular Electron Acceptors in Iron-Deficient Roots of Phaseolus vulgaris L. Plant Physiol. 1984 Dec;76(4):943–946. doi: 10.1104/pp.76.4.943. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sijmons P. C., van den Briel W., Bienfait H. F. Cytosolic NADPH is the electron donor for extracellular fe reduction in iron-deficient bean roots. Plant Physiol. 1984 May;75(1):219–221. doi: 10.1104/pp.75.1.219. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tipton C. L., Thowsen J. Fe reduction in cell walls of soybean roots. Plant Physiol. 1985 Oct;79(2):432–435. doi: 10.1104/pp.79.2.432. [DOI] [PMC free article] [PubMed] [Google Scholar]
- de Vos C. R., Lubberding H. J., Bienfait H. F. Rhizosphere acidification as a response to iron deficiency in bean plants. Plant Physiol. 1986 Jul;81(3):842–846. doi: 10.1104/pp.81.3.842. [DOI] [PMC free article] [PubMed] [Google Scholar]