Copper and cobalt accumulation in plants: a critical assessment of the current status of knowledge
Résumé
This review synthesizes contemporary understanding of Cu-Co tolerance and accumulation in plants. Accumulation of foliar Cu and Co to >300 μg g-1 is exceptionally rare globally, and known principally from the Copperbelt of Central Africa. Cobalt accumulation is also observed in a limited number of Ni hyperaccumulator plants occurring on ultramafic soils around the world. None of the putative Cu or Co hyperaccumulator plants appears to comply with the fundamental principle of hyperaccumulation as foliar Cu-Co accumulation is strongly dose-dependent. Abnormally high plant-tissue Cu concentration occurs only when plants areexposed to high soil Cu concentrations with a low shoot translocation factor. Most Cu tolerant plants are Excluders sensu Baker and therefore setting threshold values for Cu hyperaccumulation is not informative. Abnormal accumulation of Co occurs under similar circumstances in the Copperbelt of the DR Congo, however, Co tolerant plants behave physiologically as Indicators sensu Baker and sporadically coincides with Ni hyperaccumulation on ultramafic soils. Practical application of Cu-Co accumulator plants in phytomining is limited due to their dose-dependent accumulation characteristics, although for Co trials may be warranted on highly Co-contaminated minerals wastes because it its high metal value.
Domaines
Géochimie
Origine : Fichiers produits par l'(les) auteur(s)
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