Effects of chromium and nickel applications on growht and mineral contents in the aquatic macrophyte Bacopa monnieri L.

In the present study, some physiological changes were investigated in B. monnieri which is treated with different concentrations of Ni (0, 5 and 50 mM), Cr (0, 5 and 50 mM) and their combinations (5 mM Ni + 5 mM Cr and 50 mM Ni + 50 mM Cr). Growth and development of B. monnieri were adversely affected by the applications which was determined by decrease in the amount of fresh and dry weight. Nickel and chromium contents of macrophyte tissues were increased with rising metal concentrations. Macro and micro nutrient contents of the macrophyte were affected by applications. Iron and copper contents of the tissues were decreased by applications. Zinc contents were generally rised by treatments, except of 50 mM Cr. Besides these, low Ni and Cr concentrations were increased in Mg, K and Ca contents. Chlorophyll-a, chlorophyll-b and carotenoid contents of macrophytes decreased by applications. Similarly, protein contents were decreased as well. Lipid peroxidation caused by Ni, Cr and Ni+Cr applications was determined from the increase in the amount of MDA. On the other hand, applications increase in proline amounts may show its role in macrophyte to metal toxicities.