Comparative hydrolysis and sorption of Al and La onto plant cell wall material and pectic materials

Wehr, J. Bernhard, Blamey, F. Pax C., Kopittke, Peter M. and Menzies, Neal W. (2010) Comparative hydrolysis and sorption of Al and La onto plant cell wall material and pectic materials. Plant and Soil, 332 1-2: 319-330. doi:10.1007/s11104-010-0297-2

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Author Wehr, J. Bernhard
Blamey, F. Pax C.
Kopittke, Peter M.
Menzies, Neal W.
Title Comparative hydrolysis and sorption of Al and La onto plant cell wall material and pectic materials
Journal name Plant and Soil   Check publisher's open access policy
ISSN 0032-079X
Publication date 2010-07
Sub-type Article (original research)
DOI 10.1007/s11104-010-0297-2
Volume 332
Issue 1-2
Start page 319
End page 330
Total pages 22
Editor Hans Lambers
Place of publication The Hague, The Netherlands
Publisher Kluwer
Collection year 2011
Language eng
Formatted abstract
Pectin, which is an important component of plant cell walls, strongly binds Al and this may play a role in expression of Al toxicity. Sorption of aluminium (Al) and lanthanum (La) from aqueous solutions onto pectic acid, Ca-pectate and plant cell wall material was pH dependent. For Al at pH 3, sorption was less than the available sorption sites (i. e., the cation exchange capacity) on all three sorbents, whereas at pH 4, sorption of Al was in excess of available sorption capacity. By contrast, sorption of the trivalent Al analogue La corresponded to the available sorption capacity on all three sorbents at pH 5. This indicates, therefore, that Al hydrolyses at ≥ pH 4, and hydrolysis increases with Al concentration in solution. Further, it is proposed that the sorption of Al to pectin leads to deprotonation of the galacturonic acid (GalA) residues. Sorption of Al to pectin limits hydrolysis of Al, thereby shifting the pH of hydrolysis to a higher value. Hydrolysis of Al results in its sorption in excess of the stoichiometric equivalent (assuming the free Al3+ ion), leading to oversaturation of the pectin with Al. Staining of the metal-pectate complexes with the metachromatic dye eosin showed that with increasing Al saturation (but not La saturation), the complex developed a positive net charge, due to formation of some positively charged Al-complexes. The development of a positive charge on the Al-pectate complex may have major effects on cellular transmembrane potential and nutrient acquisition by plant roots. This is the first report of Al binding in excess of binding sites and development of a net positive charge on Al-pectate.
© 2010 Springer Science+Business Media B.V.
Keyword Pectin
Metachromatic dyes
Ion-exchange equilibria
Calcium pectate
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Agriculture and Food Sciences
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Citation counts: TR Web of Science Citation Count  Cited 4 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 5 times in Scopus Article | Citations
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Created: Sun, 27 Jun 2010, 00:02:39 EST