Abstract
An internal detoxification mechanism for Al was investigated in an Al-accumulating plant, hydrangea (Hydrangea macrophylla), focusing on Al forms present in the cells. The leaves of hydrangea contained as much as 15.7 mmol Al kg-1 fresh weight, and more than two-thirds of the Al was found in the cell sap. Using 27Al- nuclear magnetic resonance, the dominant peak of Al was observed at a chemical shift of 11 to 12 parts per million in both intact leaves and the extracted cell sap, which is in good accordance with the chemical shift for the 1:1 Al-citrate complex. Purification of cell sap by molecular sieve chromatography (Sephadex G-10) combined with ion-exclusion chromatography indicated that Al in fractions with the same retention time as citric acid contributed to the observed 27Al peak in the intact leaves. The molar ratio of Al to citric acid in the crude and purified cell sap approximated 1. The structure of the ligand chelated with Al was identified to be citric acid. Bioassay experiments showed that the purified Al complex from the cell sap did not inhibit root elongation of corn (Zea mays L.) and the viability of cells on the root tip surface was also not affected. These observations indicate that Al is bound to citric acid in the cells of hydrangea leaves.
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- Jones D. L., Kochian L. V. Aluminum Inhibition of the Inositol 1,4,5-Trisphosphate Signal Transduction Pathway in Wheat Roots: A Role in Aluminum Toxicity? Plant Cell. 1995 Nov;7(11):1913–1922. doi: 10.1105/tpc.7.11.1913. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jones K. H., Senft J. A. An improved method to determine cell viability by simultaneous staining with fluorescein diacetate-propidium iodide. J Histochem Cytochem. 1985 Jan;33(1):77–79. doi: 10.1177/33.1.2578146. [DOI] [PubMed] [Google Scholar]
- Lazof D. B., Goldsmith J. G., Rufty T. W., Linton R. W. Rapid Uptake of Aluminum into Cells of Intact Soybean Root Tips (A Microanalytical Study Using Secondary Ion Mass Spectrometry). Plant Physiol. 1994 Nov;106(3):1107–1114. doi: 10.1104/pp.106.3.1107. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miyasaka S. C., Buta J. G., Howell R. K., Foy C. D. Mechanism of aluminum tolerance in snapbeans : root exudation of citric Acid. Plant Physiol. 1991 Jul;96(3):737–743. doi: 10.1104/pp.96.3.737. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Suhayda C. G., Haug A. Organic acids prevent aluminum-induced conformational changes in calmodulin. Biochem Biophys Res Commun. 1984 Feb 29;119(1):376–381. doi: 10.1016/0006-291x(84)91662-0. [DOI] [PubMed] [Google Scholar]