Effects of some terricolous lichens [Cladonia rangiformis Hoffm., Peltigera neckerii Hepp ex Müll. Arg., Peltigera rufescens (Weiss) Humb.] on soil bacteria in natural conditions

This paper is aimed to investigate the effects of some terricolous lichens on soil bacteria’s growth in natural conditions. It is focused on species of bacteria and also on numbers of colony of soil specimens that were taken from substrates of three different terricolous lichen species. <I>Peltigera rufescens</I> (Weiss) Humb., which has not secondary metabolites, did not show an inhibition effect on soil bacteria. However, <I>Peltigera neckerii</I> Hepp ex Müll. Arg., which has secondary metabolites, has a negative effect on soil bacteria’s growth. Besides, it was observed that<I> Cladonia rangiformis</I> Hoffm., which has many kinds of secondary metabolites, has the highest inhibition effect among the studied species. For this reason, we think that in the next researches, it is convenient to investigate elaborately by soil analysis the effect of lichen’s secondary metabolites that have an effect on soil mineralization, on soil bacteria’s growth.

The Effect of UV-B Radiation on the Antioxidant System in the Peltigera aphthosa and Peltigera rufescens Lichens

Ultraviolet (UV) radiation is the short wavelength region of the solar spectrum. The high-energy photons of UV-B (280–315 nm) are potentially dangerous for all living organisms. The effect of UV-B radiation on lichens has not been studied sufficiently. We conducted a comparative study of the effects of the long-term (10 d) exposure to the environmentally realistic dose of UV-B radiation on the accumulation of lipid peroxidation products (TBARS), H2O2 content, superoxide dismutase (SOD) activity, and respiration rate in Peltigera aphthosa from the forest community and Peltigera rufescens from the open spaces of floodplain meadow. The H2O2 content and the SOD activity were found to increase in the thalli of P. rufescens. The TBARS content in the UV-B treated thalli of P. rufescens did not differ from the control thalli and was 2.5 times higher than in P. aphthosa. In P. aphthosa thalli, SOD activity did not change after UV-B exposure, and TBARS content increased by 33 % with an increase in the total UV-B dose. Both lichens exhibited an increase in the alternative respiratory pathway (AP) activity and a decrease in the ratio of the main (cytochrome) pathway to the energy low efficient AP. The AP involvement was more pronounced in P. aphthosa. The results of our study indicate the species-specific response in lichens and differences in their resistance to oxidative stress, which were due to adaptation to the light conditions in the typical habitats of these species