Resumo

CEN-CEN, Elmi Roseida; GOMEZ-MERINO, Fernando  e  MARTINEZ-HERNANDEZ, Aída. Tolerance of Agave tequilana to high levels of divalent metal cations. Polibotánica [online]. 2015, n.40, pp.163-182. ISSN 1405-2768.

The agaves belong to a plant genus which includes many species adapted to grow in numerous habitats, some of them with extreme environmental conditions. Distinct agave species grow on different soil types, some in soils with a low mineral nutrient content, and others in saline soils or in soils contaminated with metal ions. The plant-soil relationship has been scarcely studied in agaves, and several questions remain to be elucidated such as their ability uptake, transport and storage mineral nutrients, the cellular and biochemical mechanisms involved in these processes, or if the agaves are specially sensitive or tolerant to metal ions. Here we report the effect on Agave tequilana young plants after exposure to cadmium, cobalt, cupper, zinc or manganese sulfate at several concentrations, under lab conditions. We also report the minimal concentration of these metal ions required to induce a toxic effect detectable with visual inspection in short exposition times (8 days); we describe the toxic effects of these metal ions on the agave plantlets and the amount of Cu²⁺, Cd²⁺ and Co²⁺ accumulated in leaves of plants exposed to high metal concentrations (milimolar). Our results show that in acute toxicity experiments under our conditions, A. tequilana has a remarkable tolerance to high concentrations of the tested metal ions, including micronutrients and toxic metals, as well as the ability to transport high quantities of these metals to aerial tissues.

Palavras-chave : Agave tequilana; mineral micronutrients; toxicity by metal ions; tolerance.