Nitrogen and protein metabolism in young pea plants as affected by different concentrations of nickel, cadmium, lead, and molybdenum

Abstract

A comparative study was carried out on the effect of molybdenum (Mo), niekel (Ni), cadmium (Cd), and lead (Pb) using concentrations of 1×10-7, 1×10-5, and 1×10-3 mol dm-3, on the metabolism of nitrogen and proteins in young pea plants (Pisum sativum L. 'NS Lim'). The highest concentrations of the investigated metals were noted to suppress the development of the aboveground parts and roots. The smallest inhibiting effect was observed in the presence of Ni, which at lowest concentration produced a stimulating effect; Pb and Cd had a similar effect. The most pronounced inhibition was caused by Mo, which decreased the growth of the roots and aboveground parts by 50% and 35%, respectively. An increase in concentration of heavy metals in the medium resulted in their increased accumulation in both the plant roots and aboveground parts. The largest accumulation in the aboveground parts was observed for Ni and Mo, followed by Cd, and least for Pb. Nitrate and protein metabolism decreased according to the order of Cd>Pb>Ni>Mo. However, when expressed per amount of heavy metal accumulated in particular plant parts, toxicity was in the order of Pb>Cd>Ni>Mo.