Response of duckweed to various concentrations of selenite

Abstract

The uptake of Se(IV) and its effects on the physiological and biochemical characteristics of duckweed (Lemna minor L.) have been studied. Duckweed plants were cultivated in controlled conditions for 7 weeks in different concentrations of Na selenite: 0.5, 1, 2, 5 (exposed 42 days) and 10 mg Se L(-1) (survived 7-21 days). The addition of 1 mg Se L(-1) did not negatively affect photochemical efficiency whilst respiratory potential increased in weeks 2-4 compared to control. The addition of 1 mg Se(IV) L(-1) increased the amount of chlorophyll a in weeks 3 and 4 and the amount of carotenoids in weeks 1, 3 and 5. Concentrations of 2 and 5 mg Se L(-1) negatively affected photochemical efficiency in weeks 3 and 4, and increased respiratory potential in comparison to the control in weeks 1-4, whilst beyond week 4, the respiratory potential decreased. Plants exposed to the highest concentration of Se(IV) had to be replaced twice during the experiment because they were dying. That was reflected in photochemical efficiency as well as in respiratory potential, which decreased in time. The content of Se in duckweed increased with the increasing concentration of Se: plants growing in 0.5 mg Se L(-1) contained 0.9 mg Se g(-1) DM and plants exposed to 5 mg Se L(-1) contained 5.8 mg Se g(-1) DM. The group of plants exposed to 10 mg Se L(-1) for 21 days contained 19.5 mg Se g(-1) DM. Our study revealed that duckweed absorbed high amount of Se(IV) from the water.

Novel bioremediation processes for treatment of seleniferous soils and sediment

“…For removing Se, aquatic plants have been mostly studied at the laboratory scale, with nutrient solutions containing only Se, either as SeO3 2or SeO4 2- (Mechora et al, 2011, Mechora et al, 2015. Carvalho and Martin (2001) (Figure 5.1a).…”

“…In this study, up to 40 µg g -1 dry weight was taken up by L. minor when 100 µg L -1 of SeO4 2was added (Figure 5.1b). Mechora et al (2015) also studied the effect of different SeO3 2concentrations in L. minor and observed that 1 mg L -1 can stimulate growth, but at higher concentrations, the plant exhibits chlorosis until 10 mg L -1 killing 50% of plants. In this study, the exposure of plants to 0.5 mg L -1 of SeO4 2in Hoagland solutions had a negative effect on the growth of plants and a decrease in the Se removal efficiency.…”

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“…Among these pesticides, azadiracthin is a natural insecticide widely used today which obtained by drying and powdering Azadirachta indica tree leaves [2]. Duckweed (Lemna minor) has been identified as a suitable plant material for ecotoxicological investigations in recent years [3][4][5][6][7]. Lemna absorbs its nutrients, ammonium and phosphate forms, from roots.…”

Effects of Glyposate on Starch Accumulation, Chlorophyll and Enzyme Activity of Duckweed (Lemna minor L.)

“…In the recent decade, Duckweeds have been investigated as a convenient plant material for ecotoxicological research. A number of researchers have searched the removal of organic and metal contaminants in wastewater with different duckweed species (Appenroth et al, 2010;Leblebici and Aksoy 2011;Mechora et al, 2015;Song et al, 2015;.…”