COMPARATIVE ANALYSIS OF THE EFFECT OF ZINC EXCESS ON THE SHOOT GROWTH OFSINAPIS ALBA AND BRASSICA JUNCEA

Abstract

The effect of zinc excess on shoot growth of white mustard ( Sinapisalba ) andsareptskaya mustard ( Brassicajuncea ) was studied. Nowadays, supposed that B.juncea is a zinc hyperaccumulator – accumulating its high concentrations in the aboveground organs. In contrast, S.alba belongs to the “excluders” and accumulate the zinc mostly in the roots. It is known, that both species are able to grow on zinc-contaminated soils, but too less known about their metal tolerance. The data about their physiological reactions to excess metal influence are contradictory.In a laboratory experiment, the effect of zinc at concentration of 5 (control), 25, 50, 100, 150 and 200 mg/kg of substrate on a shoot growth parameters in S.alba cv. Radugaand B.juncea cv. Slavanka was studied. Our studies showed, that the effect of zinc on shoot growth mostly depends on the zinc concentration in the substrate as well as the plant species. Thus, zinc at concentration of 25 and 50 mg/kg had a stimulating effect on the growth of shoots of S.alba and only higher concentration of the zinc (100-200 mg/kg) led to decrease in the studied parameters. In B.juncea, even at a metal concentration of 50 mg/kg decrease in shoot height and leaf area. In concentration dependent matter the negative effect was observed. We supposed the the stronger negative effect of zinc at the studied concentrations on the shoot growth of B. juncea as a hyperaccumulator compared to S.alba is associated with a higher content of the metal in its aboveground part. Our results demonstrate the possibility of using studied varieties of S.alba and B. juncea in phytoremediation of zinc contaminated soils.