Metal uptake and detoxification mechanisms in Erica andevalensis growing in a pyrite mine tailing

• Published in: Environmental and experimental botany Vol. 61; no. 2; pp. 117 - 123
• Main Authors: Turnau, Katarzyna, Henriques, Fernando S., Anielska, Teresa, Renker, Carsten, Buscot, François
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2007; Elsevier Science
• Subjects: Al-accumulator; aluminum; Biological and medical sciences; Cell physiology; cell walls; epidermis (plant); Erica; Erica andevalensis; extracellular matrix; Fundamental and applied biological sciences. Psychology; heavy metals; Hymenoscyphus ericae; hyperaccumulators; iron; metabolic detoxification; mine spoil; Mycorrhiza; parenchyma; plant glands; Plant physiology and development; Plasma membrane and permeation; Pyrite tailings; pyrites; quantitative analysis; roots; shoots; Si deposition; silicon; soil pollution; symbionts; symbiosis; trichomes; Portugal; Pyrite tailings; Al-accumulator; Hymenoscyphus ericae; Si deposition; Erica andevalensis; Mycorrhiza; Dicotyledones; Angiospermae; Detoxification; Spermatophyta; Ericaceae; Erica
• DOI: 10.1016/j.envexpbot.2007.05.001
• ISSN: 0098-8472

Erica andevalensis was found growing in the banks of extremely acidic, heavily metal-contaminated tailings of an abandoned pyrite mine in the Mértola region of southeastern Portugal. Elemental analysis by ICP-AES and AAS showed that Al and Fe, quantitatively the two principal contaminants of the plant's substrate, accumulated in the plant, reaching average concentrations of 1745 (±81) and 2328 (±745) mg kg −1 of leaf dry weight, respectively. Quantitative EDX-analysis of the spatial distribution of these elements within the roots and shoots of E. andevalensis revealed that they were predominantly detected in the cell walls of epidermal tissues, as well as in leaf glandular hairs. This finding indicates that sequestration of Al and Fe in the extracellular matrix of protective tissues, away from the internal parenchymas, constitutes an important detoxification mechanism. Si was always found to co-localize with Al and Fe, which would support its proposed role in alleviating metal toxicity. Hymenoschyphus ericae was identified as the fungal endosymbiont of Erica roots and both its extra- and intraradical mycelia accumulated exceedingly high metal levels, thus effectively contributing to reduce metal availability for the plant. It is concluded that E. andevalensis works with its fungal partners to exclude contaminating metals from intracellular sites where they could disrupt normal cell functioning.