resumo
Cistus monspeliensis L. is a species that grows spontaneously in contaminated mining areas of the Iberian Pyrite Belt. This species can accumulate high concentrations of As in the shoots without visible signs of phytotoxicity. In order to understand the physiological mechanisms underlying this tolerance, C. monspeliensis was grown in an Arenosol irrigated with aqueous nutrient solutions containing increasing concentrations of As (0, 1500, 5000, 10000, 15000 mu M) and the effects of this metalloid on plant development and on the defence mechanisms against oxidative stress were monitored. Independently of the treatment, As was mainly retained in the roots. The plants with the highest concentrations of As in the shoots (> 5000 mu M) showed toxicity symptoms such as chlorosis, low leaf size and decrease in biomass production and also nutritional deficiencies. Most of the studied physiological parameters (pigments, glutathione, ascorbate and antioxidative enzymes) showed significant correlation with As concentration in roots and shoots. Pigments, especially anthocyanins, were negatively affected even in the treatments with the lowest As concentrations. Glutathione increased significantly in roots at low As levels while in shoots this increase occurred in all As treatments. Ascorbate decreased in both tissues with As addition. The highest concentrations of As in shoots of C. monspeliensis triggered defence mechanisms against oxidative stress, namely by inducing the expression of genes coding antioxidative enzymes.
palavras-chave
HYPERACCUMULATOR PTERIS-VITTATA; INDUCED OXIDATIVE STRESS; ARABIDOPSIS-THALIANA; ANTIOXIDANT SYSTEM; ARSENATE TOXICITY; DEFENSE SYSTEM; TRACE-ELEMENTS; LADANIFER L.; ZEA-MAYS; RESPONSES
categoria
Environmental Sciences & Ecology; Toxicology
autores
Carvalho, LC; Santos, ES; Abreu, MM
nossos autores
Erika da Silva dos Santos
Bolseiro de pós-DoutoramentoGrupos
agradecimentos
The authors wish to thank Ftmdacao para a Ciencia e Tecnologia (FCT) for financial funding of LEAF and CICECO Research Centres (UID/AGR/04129/2013 and UID/CTM/50011/2013, respectively) and support to LCC and ESS through the pos doctorate grants, SFRH/BPD/109428/2015 and SFRH/BPD/117556/2016, respectively. The authors also wish to acknowledge the laboratory work performed by Jose A. Nunes.