Physiological response of barley plants (Hordeum vulgare) to cadmium contamination in soil during ontogenesis

A study was made on the physiological response of two winter barley cultivars (Obzor and Hemus), grown as pot-soil cultures, to cadmium treatment. It was established that a soil Cd concentration of 45 mg/kg inhibited dry mass accumulation and suppressed development of barley plants. The unfavourable Cd effect was better expressed in the plants of cv. Hemus and more significant at the early phenological stages of vegetation. Visual symptoms of phytotoxicity were observed in roots, where the Cd concentration was about 10 times higher than in the above-ground organs. In the overground parts of plants, the highest concentration was found in the lower leaves, increasing during ontogenesis. In the other parts, the Cd concentration decreased during ontogenesis towards stems, leaves of the upper floor, ears and grains. A slight tendency to decrease in the photosynthetic rate was observed in the Cd-treated plants of both cultivars. The rate of transpiration as well as the plastid pigment concentration did not change significantly.