The effect of equal Cd and Cu exposure in peat substrate on growth and bioaccumulation of Hordeum vulgare

Abstract

The Authors’ report was presented at the 9th International Scientific Conference “The Vital Nature Sign 2015”. Environment pollution with heavy metals is becoming more important these days. In this work we investigated the impact of soil contaminated with various concentrations of two heavy metals Cd and Cu (100; 200; 400; 800 and 1 600 mg/kg soil) on barley (Hordeum vulgare) growth and bioaccumulation. Investigated plants were sown in vegetative pots with the prepared peat and sand substrate (ratio 2:1), and 4 days after germination the plants were watered with appropriate metal concentration solutions. The experiment lasted for 14 days until the second true leaf unfolded. At the end of the experiment, the content of pigments was measured using a spectrophotometer, MDA was determined using the thiobarbituric acid method, and plants height and dry mass were also detected. Increasing of metal concentrations decreased plant height and biomass, and the Cd effect on morphological parameters was higher than that of Cu when a correlation between barley height and Cd concentration was –0.74 (p < 0.05) and between barley height and Cu concentration –0.39 (p < 0.05). Increasing metal concentrations effect on photosynthesis pigments was different, i. e. under the Cu effect the content of pigments (a+b) increased and a correlation was 0.47 (p > 0.05), while under the Cd effect it decreased and a correlation was –0.13 (p > 0.05), but statistically insignificant. Between MDA concentration in barley leaves and heavy metals concentration in the  substrate a  strong correlation (p  <  0.05) was estimated, which was slightly stronger under the copper impact. At lower concentrations lower MDA levels were detected there, compared to those of the control plants, when the concen­tration increased up to 1 600 mg Cu and Cd/kg substrate, the MDA concentrations increased statistically significantly by 68 and 32%, respectively. Up to 800 mg/kg concentration in the substrate accumulation of copper was more willing than accumulation of cadmium in barley leaves (p  <  0.05), but when the concentration rises up to 1 600 mg/kg, the plant starts to accumulate more Cd than Cu.