Effect of UV-B radiation on the contents of UV-B absorbing compounds and photosynthetic parameters in Parmotrema austrosinense from two contrasting habitats

MARE?KOVÁ, M; HÁJEK, J; BARTÁK, M; MORKUSOVÁ, J; PLÁTENÍKOVÁ, E; MATEOS, A C; CARRERAS, H

PLANT BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018

1435-8603

We studied the resistance of Parmotrema austrosinense to UV-B stress. We focused on the effects of a high dose UV-B radiation on the contents of (chlorophylls, carotenoids) and UV-B screening compounds. Photosynthetic parameters were measured by chlorophyll fluorescence (potential and effective quantum yields, photochemical and non-photochemical quenching) and evaluated in control and UV-B treated lichens as well. Lichens from two different locations in Cordoba, Argentina were selected: (1) high altitude and dry plots at (Los Gigantes) and (2) lowland high salinity plots (Salinas Grandes). UV-B treatment led to a decrease in the content of photosynthetic pigments and UV-B screens (absorbance decrease in 220-350 nm), in the samples from Salinas Grandes, while in Los Gigantes samples, an increase in UV-B screens contents was observed. Chlorophyll fluorescence parameters showed UV-B induced decline in FV/FM, PSII and qP indicating limitation of primary photosynthetic processes in photosystem II of symbiotic alga, more pronounced in Salinas Grandes samples. Protective mechanism of PS II were activated by the UV-B treatment to a higher extent in the samples from Salinas Grandes (NPQ of 0.48) than in Los Gigantes samples (NPQ of 0.26). We concluded that site-related characteristics and in particular different UV-B radiation regimen, had a strong effect on resistance of photosynthetic apparatus of P. austrosinense to UV-B radiation.