Research Article

The Influence of pH and Lichen Metabolites (Vulpinic Acid and (+) Usnic Acid) on the Growth of the Lichen Photobiont Trebouxia 1rregularis

M. Bačkora1a2, J. Hudáa1, M. Repčáka2, W. Ziegler§a3 and M. Bačkorováa1

a1 Department of Plant Physiology, Faculty of Natural Sciences,Comenius University, Mlynská dolina B-2, SK-842 15 Bratislava, Slovak Republic.

a2 Department of Experimental Botany and Genetics, Faculty of Natural Sciences, Šafárik University, Mánesova 28, SK-041 67 Košsice, Slovak Republic, (correspondence address) E-mail:

a3 Department of Biophysics and Chemical Physics, Comenius University, Mlynská dolina F-l, SK-842 15 Bratislava, Slovak Republic.


The quantitative response to two lichen metabolites, vulpinic acid and (+) usnic acid, on biomass production by the photobiont Trebouxia irregularis, isolated from the lichen Cladina mitis, was determined experimentally. The presence of usnic acid resulted in inhibition of photobiont growth, and the effect depended on the pH of the culture medium. The concentration effect of usnic acid was observed. The application of vulpinic acid almost completely inhibited the growth of T.irregularis and no significant differences were found among samples at different medium pH values.