Short-term physiological responses to copper stress in Salvinia auriculata Aubl.

Abstract

Aim: To evaluate, in a short-time exposure, the physiological responses of Salvinia auriculata Aubl. under different concentrations of Cu. Methods: The plants were exposed to treatments with 0.01, 0.1, 1 and 10 mM of Cu in a period of 2 days. Then development variables of S. auriculata (weight, photosynthetic pigments, and soluble carbohydrate), lipid peroxidation (malondialdehyde, aldehydes, and electrolyte leakage) and production of antioxidants (anthocyanins, carotenoids, flavonoids, and proline) were evaluated. Results: It was observed fresh weight reductions in concentrations above 1 mM of Cu. Chlorophyll a decreased with the increase of Cu concentrations unlike chlorophyll b. The ratio chlorophyll a / chlorophyll b was changed due to the degradation of photosynthetic pigments. The reductions of carotenoids were more pronounced than that of total chlorophyll. The values of electrolyte leakage ranged from 14 to 82 % and lipid peroxidation from 7 to 46 nmol.g -1. Flavonoids and soluble carbohydrates showed reductions with the increase of Cu concentration. Anthocyanins, phenolic compounds, and proline when subjected to 0.1 mM of Cu had increased, suggesting adaptability of plant stress caused directly by metal and reactive oxygen species. In higher concentrations, degradation and/or direct modifications of these molecules possibly occurred. Conclusions: The data suggest that S. auriculata is provided with an efficient mechanism against stress caused by Cu in the concentration of 0.1 mM. As for higher concentrations (1 and 10 mM), despite its role as micronutrients, Cu was toxic to the plant due to the redox behavior of this metal, which leads to the exacerbated formation of reactive oxygen species, inducing to severe damage such as biological membrane degradation and protein denaturation.Keywords: lipid peroxidation, antioxidant, proline, metal stress.Resumo: Objetivo: avaliar em curto tempo de exposição às respostas fisiológicas de Salvinia auriculata Aubl. sob diferentes concentrações de Cu. Métodos: as plantas foram expostas a tratamentos com 0,0; 0,01; 0,1; 1 e 10 mM de Cu em um período de 2 dias. Em seguida foram avaliadas variáveis de desenvolvimento de S. auriculata (peso, pigmentos fotossintéticos e carboidratos solúveis), peroxidação lipídica (malonaldeído, aldeídos e extravasamento de eletrólitos) e produção de antioxidantes (antocianinas, carotenóides, flavonóides e prolina). Resultados: Foram verificadas reduções das massas frescas nas concentrações acima de 1 mM de Cu. A clorofila a reduziu com o aumento da concentração de Cu, diferentemente da clorofila b. A razão clorofila a/clorofila b foi alterada, devido à degradação dos pigmentos fotossintéticos. As reduções dos carotenóides foram mais acentuada do que a de clorofila total. Os valores de extravasamento de eletrólitos variaram de 14 a 82 % e peroxidação lipídica de 7 a 46 nmol.g -1. Flavonóides e carboidratos solúveis mostraram reduções com o aumento da concentração de Cu. Antocianinas, compostos fenólicos e prolina quando submetida...

Variations in the Phytoremediation Efficiency of Metal-polluted Water with Salvinia biloba: Prospects and Toxicological Impacts

“…Moreover, some related studies have reported an increase in the total amount of flavonoids and anthocyanins in Salvinia sp. exposed to metal(loids) indicating that these compounds could be involved in metal tolerance described for these aquatic ferns [19,23,50]. However, in our study, no increase in antioxidant pigments content was observed, possibly because the amount of Cu, Cd, Pb, and Zn accumulated into S. biloba leaves was not detrimental at the oxidative level.…”

“…Anthocyanin content was determined according to [23]. Briefly, plant samples (50.0 mg FW) were incubated with 5.0 mL of methanol:HCl (99:1) and kept in the dark for 24 h. The extract was then centrifuged at 2500× g for 10 min.…”

“…Soluble carbohydrate content was determined according to [23]. One-hundred milligram (100 mg) of fresh leaf biomass was mixed with 2.0 mL of 80% (v/v) methanol and heated at 70 • C for 30 min.…”

Assessment of the physiological condition of Salvinia natans L. exposed to copper(II) ions

“…Bizzo et al [14] in experiments with Salvinia auriculata Ablu. cultures at lower concentrations of copper (0.01 and 0.1 mM Cu) after 2 days obtained 430.2 (79% of initial value) and 495.4 (91%) g of chlorophyll a/g of fresh matter (control: 544.7 g of chlorophyll a/g of fresh matter), 193.2 (94%) and 216.0 (105%) g of chlorophyll b/g of fresh matter (control: 205.4 g of chlorophyll b/g of fresh matter) and 632.4 (84%) and 711.3 (95%) g of total chlorophyll/g of fresh matter (control: 750.2 g of total chlorophyll/g of fresh matter).…”

“…Bizzo et al [14] investigated the influence of Cu in various concentrations (0.01, 0.1, 1 and 10 mM) on the development of Salvinia auriculata Ablu., in a short-time exposure of plants (2 days). The results have shown high tolerance of Salvinia auriculata Ablu.…”