Ecophysiological adaptation and metal accumulation in water hyacinth from two tropical rivers

Abstract

The ecophysiological adaptations of water hyacinth (metal hyperaccumulator) under adverse environmental conditions are not yet clearly elucidated. This work evaluated photosynthetic pigments and chlorophyll a fluorescence in water hyacinth plants sampled in different regions (upper, middle and lower) of Paraíba do Sul river (PSR) and Imbé river, Brazil. Additionally Mn, Fe, Zn, Cu, Cr, Pb and Ni were quantified on the shoots and roots. Roots were the preferential site of metal accumulation. Cromium was not detected in the shoots. Iron and Mn were the elements detected in higher concentrations in all samples. Zinc and Cu were detected in higher concentrations in roots of plants from middle and upper PSR, sites of higher anthropogenic activity. The highest concentrations of almost all metals were verified in plants from middle PSR. Regarding photosynthetic adaptations, plants from middle and upper PSR showed the highest concentrations of photosynthetic pigments, as well as the highest values of F v /F m and F v /F 0 . The photosynthetic performance of plants suggests that they are not under stress conditions, even in regions of higher anthropogenic activity. Positive correlation was observed among nonphotochemical quenching and carotenoids, suggesting dissipation of energy in the form of heat as an strategy to keep the stable photochemical photosynthesis functioning, confirmed by values of the F v /F m . It is possible that such adaptative strategy is efficient as a long term response to stress factors, once literature data suggest that this is not a preferential path for photosynthesis in stress circumstances under short time controlled conditions. Key-words: pollution, Paraíba do Sul river, energy dissipation, photosynthetic pigments, nonphotochemical quenchings. resuMoAs adaptações ecofisiológicas de aguapé (hiperacumuladora de metais) sob condições ambientais adversas ainda não estão totalmente elucidadas. Este trabalho avaliou pigmentos fotossintéticos e fluorescência da clorofila a em aguapé coletados em diferentes regiões (alto, médio e baixo) do rio Paraíba do Sul (RPS) e no rio Imbé, Brasil. Adicionalmente Mn, Fe, Zn, Cu, Pb e Ni foram quantificados na parte área e raízes. Ferro e Mn foram os elementos detectados em maiores concentrações em todas as amostras. Zinco e Cu foram detectados em maiores concentrações nas raízes de plantas do médio e alto RPS, locais de grande atividade antropogênica. As mais elevadas concentrações de quase todos os metais foram verificadas nas plantas do médio RPS. Com relação às adaptações fotossintéticas, plantas do médio e alto RPS mostraram as maiores concentrações de pigmentos fotossintéticos, assim como os mais elevados valores de F v /F m e F v /F 0 . As avaliações fotossintéticas destas plantas sugerem que elas não estejam sob condições de estresse, mesmo nas regiões de grande atividade antropogênica. Correlação positiva foi observada entre quenching não-fotoquímico e carotenóides, sugerindo que a dissipação de energia na forma de calor seja uma estratégia para ...

Photosynthetic performance and anatomical adaptations in Byrsonima sericea DC. under contrasting light conditions in a remnant of the Atlantic forest

“…Statistical analysis indicated the Fv/F0 ratio as the more effective in discriminating the efficiency of the photosynthetic apparatus. Others authors have suggested the use of the Fv/F0 ratio, rather than the Fv/Fm ratio, for better discrimination of small differences in the PS II quantum yield (Paiva et al, 2009;Pereira et al, 2000;Sarajeva et al, 2007;Oliveira et al, 2009;Vitória et al, 2010). In contrast, Roháček (2002) reported that the Fv/ F0 ratio in healthy plants can vary between 4 and 6, suggesting that despite it decreases in sun plants during the rainy season, this could not be well correlated with a stressed condition, as the performance of PS II quantum yield proved to be .…”

Study of Toxic Elements in River Water and Wetland Using Water Hyacinth (Eichhornia crassipes) as Pollution Monitor

“…The concentrations of toxic elements in the water hyacinth obtained from rivers located in different parts of the world as reported in literature are shown in Table 2 .…”

Structural and ecophysiological alterations of the water hyacinth [Eichhornia crassipes (Mart.) Solms] due to anthropogenic stress in Brazilian rivers

“…Different reports with water hyacinth have shown that most of the metal up-taken by this plant species is accumulated preferentially in the roots (Soltan and Rashed, 2003;Lu et al, 2004;Paiva et al, 2009;Vitória et al, 2010). The accumulation of metals in the root system appears to minimize any major effect on the biomass production and to reduce the harmful symptoms (Verkleij and Prast, 1989).…”

“…Paraíba do Sul river (PSR) is a tropical river of medium size with approximately 1,145 km length and a drainage basin of 55,400 km 2 that serves three of the most important and populated Brazilian States. As a consequence, their waters are in constant association with the anthropogenic substances of toxic nature, exposing especially aquatic biota to stressful conditions (Azevedo et al, 2004;Campaneli et al, 2010;Vitória et al, 2010). The investigations on the plant performance in the natural conditions are essential to access the life conditions in contaminated environments.…”

“…The investigations on the plant performance in the natural conditions are essential to access the life conditions in contaminated environments. Under this context, water hyacinth has been considered a good model for such studies due to its ability to survive under various environmental circumstances (Mangabeira et al, 2004;Mahmood et al, 2005;Lage-Pinto et al, 2008;Vitória et al, 2010). In the present study, water hyacinth plants from three regions of PSR, with different contamination levels, and from the Imbé river were studied.…”