Selenium uptake, translocation and speciation in wheat supplied with selenate or selenite

A - Papers appearing in refereed journals

Li, H-F., McGrath, S. P. and Zhao, F-J. 2008. Selenium uptake, translocation and speciation in wheat supplied with selenate or selenite. New Phytologist. 178 (1), pp. 92-102.

AuthorsLi, H-F., McGrath, S. P. and Zhao, F-J.
Abstract

Selenite can be a dominant form of selenium (Se) in aerobic soils; however, unlike selenate, the mechanism of selenite uptake by plants remains unclear. Uptake, translocation and Se speciation in wheat (Triticum aestivum) supplied with selenate or selenite, or both, were investigated in hydroponic experiments. The kinetics of selenite influx was determined in short-term (30 min) experiments. Selenium speciation in the water-extractable fraction of roots and shoots was determined by HPLC-ICPMS. Plants absorbed similar amounts of Se within 1 d when supplied with selenite or selenate. Selenate and selenite uptake were enhanced in sulphur-starved and phosphorus-starved plants, respectively. Phosphate markedly increased K-m of the selenite influx. Selenate and selenite uptake were both metabolically dependent. Selenite was rapidly converted to organic forms in roots, with limited translocation to shoots. Selenomethionine, selenomethionine Se-oxide, Se-methyl-selenocysteine and several other unidentified Se species were detected in the root extracts and xylem sap from selenite-treated plants. Selenate was highly mobile in xylem transport, but little was assimilated to organic forms in 1 d. The presence of selenite decreased selenate uptake and xylem transport. Selenite uptake is an active process likely mediated, at least partly, by phosphate transporters. Selenite and selenate differ greatly in the ease of assimilation and xylem transport.

KeywordsPlant Sciences
Year of Publication2008
JournalNew Phytologist
Journal citation178 (1), pp. 92-102
Digital Object Identifier (DOI)doi:10.1111/j.1469-8137.2007.02343.x
PubMed ID18179602
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeSEF
ISSN0028646X
PublisherWiley

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