Resumo

MICHEL-LOPEZ, Claudia Yared et al. Bioaccumulation and changes in the photosynthetic apparatus of Prosopis juliflora exposed to copper. Bot. sci [online]. 2016, vol.94, n.2, pp.323-330. ISSN 2007-4476.  https://doi.org/10.17129/botsci.507.

The effect of copper toxicity on the photosynthetic activities and bioaccumulation in different tissues of Prosopis juliflora was investigated using three CuSO4 concentrations (10, 50 and 100 mM) added under hydroponic conditions. Copper concentration and chlorophyll fluorescence were measured after 48 h of copper stress. The results obtained in this study show that increasing levels of 50 and 100 mM Cu2+ resulted in a significant accumulation of this metal mainly in roots compared with control roots. On the other hand, our result showed a significant reduction of maximum photochemical efficiency of photosystem II (Fv/Fm) and the activity of photosystem II (F v /F 0 ) ratios in P. juliflora leaf treated with 100 mM Cu2+ with respect to control after 4h of exposure. These changes suggested that the photosynthetic apparatus of P. juliflora was the primary target of the Cu2+ action. Therefore the information provided by this short-term (48 h) experiment in P. juliflora showed that several physiological processes are activated, in which the copper uptake by roots and their accumulation in tissues play a central role. In conclusion, the chlorophyll fluorescence parameters can be used as a useful physiological tool to assess early changes in photosynthetic performance of P. juliflora in response to copper pollution in short-term. Finally, the present study showed that P. juliflora is a promising prospect for heavy metals phytoremediation purposes occurring in arid and semi-arid climates in the northwest Mexico.

Palavras-chave : bioaccumulation; chlorophyll fluorescence a; heavy metals; Prosopis juliflora.