Effects of heavy metals on physiological parameters of the lichens

Abstract

Determinig the accumulation and detoxification of heavy metals present a principal problem in order to understand environmental pollution of heavy metals. The objective of this study was to determine the effect of cadmium on lichens physiology and it accumulation in the lichens thalli. Samples of epiphytic lichen Evernia prunastri, Ramalina fastigiata and Ramalina farinacea were soaked in cadmium containing solutions, namely 5, 25, 50 and 500 M. In order to determine cadmium impact on lichens the following parameters were determined: chlorophyll a and chlorophyll b as indicators of algae viability, potential quantum yield of PSII as fluorescence ratio (Fv/Fm) and oxidative stress parameter as production of malondialdehyde. Photosynthetic characteristics were negatively affected, indicated by decrease in pigments content and photosynthetic efficiency. Cd content in treated lichens thalli increased gradually as Cd concentration increased in treatment solutions. An increase in MDA concentration was significantly higher in the highest Cd concentrations. Our results showed that E. prunastri was more sensitive to Cd exposure with higher Cd content bounded at intracellular sites.