Heavy metals bioaccumulation and physiological responses to heavy metal stress in populations of Silene vulgaris Moench (Garcke) from heavy metal contaminated sites

Abstract

In this study we have evaluated the heavy metals accumulation in the leaves of Silene vulgaris and its influence on glutathione, free amino acids and anthocyanins concentrations.Glutathione is a tripeptide (γ-Glu-Cys-Gly) which is involved in many metabolic processes of a plant cell. It is related to the sequestration of xenobiotics and heavy metals and it is also an essential component of the antioxidant system, which keeps reactive oxygen species under control. The accumulation of anthocyanin pigments in the leaves can be induced by environmental and anthropogenic stressors, such as pollution, osmotic stress, and nutrients deficiency. The positive role of anthocyanins as well as amino acids and organic acids in metal sequestration is suggested. Samples of Silene vulgaris leaves were collected in May and July 2003–2005 from the heavy metals contaminated sites – from the nearest vicinity of non-ferrous metal smelter Szopienice at the distance of 50, 250, 450 m, from zinc wastes heap in Katowice and from a former calamine site in Dąbrowa Górnicza (the South of Poland). In the previous study we noted that the nearest vicinity of non-ferrous metal smelter Szopienice was more polluted than the other areas. The highest Zn, Cd and Pb accumulation in the leaves of Silene vulgaris was noted in the plants collected in the nearest vicinity of the non-ferrous metal smelter Szopienice. The free amino acids concentrations have differed in the vegetative season. It was higher in the most polluted sites (50 and 250 m) in July. Higher content of the reduced form of glutathione was estimated in the plant leaves collected in the distance of 250 m from the emitter in July than at the beginning of the study. Also the highest anthocyanins accumulation in Silene vulgaris leaves was noticed in July and in plants from the most polluted area (250 m). The estimations, especially glutathione content, seem to be promising in ecophysiological research connected with heavy metals stress in plants growing in the postindustrial areas.