Pigment composition, glutathione and tocopherols in green algal and cyanobacterial lichens and their response to different light treatments

This study investigated photosynthetic pigments chlorophyll a and b, carotenoids (including xanthophyll cycle pigments) and antioxidants glutathione and tocopherols contents in chloro- (Lobaria pulmonaria, Lasallia pustulata) and cyanolichens (Lobaria scrobiculata, Peltigera canina) from different habitats and of different geographical origin. Lichen thalli were treated with various levels of irradiance (from 100 to 1500 mmol m-2 s-1) for various time periods (from 20 min. to 5 h). The extent of increase of zeaxanthin content after different light treatments differed among chlorolichens, clearly distinguishing the species from light and shade habitats. Irrespective of light treatment, β-carotene content was always higher in cyanobacterial species than in green algal species. Highest canthaxanthin concentration, as well as β-carotene concentration, was found in L. scrobiculata from shade habitat. The content of total glutathione was the same in the same species from different collection sites. On the contrary, contents of a-tocopherol differed in the same species from different collection sites.