A new species of lichenized ascomycete, Massalongia olechiana Alstrup et Søchting, sp. nov. (Massalongiaceae) is described from the South Shetland Islands and the Antarctic Peninsula. The species is distinguished by laminal isidia and 5–7−septate ascospores. The relationships with the other species of the genus are discussed. From Massalongia carnosa , recorded from both the Arctic and the Antarctic, the new species is distinguished by its lack of isidioid squamules and in having pluriseptate ascospores instead of 1−septate ascospores
Carotenoid composition of both penguin faeces and the lichen Caloplaca regalis has been analyzed by thin layer chromatography. Carotenoids in both samples are almost identical to those found in the krill, the main food of the penguins, including β-carotene, which is not found in other Theloschistaceae species.
Lichens, as typical obligate associations between lichenized fungi and their photosynthetic partners, are dominant in Antarctica. Three Antarctic lichens, Ochrolechia frigida , Umbilicaria antarctica , and Usnea aurantiaco−atra with different growth forms, were sampled nearby the Great Wall Station, King George Island. Molecular data revealed that the photosynthetic algae in these three lichens were Trebouxia jamesii . The net photo − synthesis (Pn) of three individuals from these species, together with environmental factors such as light and temperature, were recorded by CO 2 gas exchange measurements using a CI−340 portable photosynthetic system in situ . Differences between T(leaf) (the temperature of the thalli) and T(air) (the air temperature) for these lichens were not consistent, which reflected that environment and the growth form of thalli could affect T(leaf) significantly. Strong irradiation was expected to have adverse effects on Pn of Ochrolechia frigida and Umbilicaria antarctica whose thalli spread flat; but this photoinhibition had little effect on Usnea aurantiaco−atra with exuberant tufted thallus. These results indicated that photo − synthetic activity in lichens was affected by the growth forms of thalli besides microhabitat factors. One species of lichenized alga could exhibit diversified types of photosynthetic behavior when it was associated with various lichenized fungi in different microhabitats. It will be helpful for understanding how lichens are able to adapt to and colonize in extreme environments.
Usnea aurantiaco-atra is the dominant flora around King George Island, Antarctica, whose specimens exhibited various phenotypes, even for those with the same ITS sequences in both mycobiont and photobiont. A comprehensive analysis of morphological traits of U. aurantiaco-atra including the reproductive structures, growth forms and ornamentation, cross section of the branches, and the substratum was carried out. Four arbitrary groups were identified based on their reproductive characters, but these groups cannot be distinguished from molecular phylogenetic trees based on fungal or algal ITS sequences. Further, the complicated morphological diversity of the thalli with the same ITS haplotypes in both mycobiont and photobiont suggest that some other factors in addition to the symbionts could influence the morphology of lichens. This implies that lichen is indeed a complex-mini-ecosystem rather than a dual symbiotic association of fungus and alga. Also, a lichenous fungi Phacopsis sp. was identified based on its anatomical characters and ITS sequence, which was also responsible for the black burls-like structures on U. aurantiaco-atra.
The paper describes anatomical and physiological features of photobionts and mycobionts in Bryoria forsteri Olech & Bystrek, Caloplaca regalis (Vain.) Zahlbr., Cetraria aculeata (Schreb.) Fr., Ramalina terebrata Hook f. & Taylor, Sphaerophorus globosus (Huds.) Vain. and Usnea antarctica Du Rietz, collected in the Antarctic under varied weather conditions. Green algae from the genera Lobosphaera and Trebouxia were gathered in depressions of the cortex under the more resistant mycobiont hyphae. In photobiont cells a large amount of highly osmiophilic electron-dense PAS-negative material, lipid-like in character, was of particular interest. Similar material also filled certain areas of the aerial apoplast. A star-shaped chromatophore with central and lateral pyrenoids encompassed most of the photobiont protoplast in all the studied species. Regularly arranged thylakoids with evenly widened lumina along their entire length and osmiophilic lipid droplets adhering to their outer surfaces were visible within the pyrenoid. Inside the chloroplast, large protein inclusions tightly joined with the thylakoids were observed. The mycobionts were closely attached to each other another and with the photobionts by means of an outer osmiophilic wall layer, and formed intramural haustoria. Their protoplasts were filled with PAS-positive polysaccharides and a large amount of lipid-like substances. The photobionts were physiologically active and produced a large amount of electron-dense osmiophilic material, and PAS-positive starch grains were visible around their pyrenoids in the thalli collected in different weather conditions. The permanent reserves of nutritive materials deposited in the thalli enable these organisms to quickly begin and continue indispensable physiological processes in the extreme Antarctic conditions.
A lichenicolous fungus, Dactylospora dobrowolskii Olech et Alstrup, new to science is described. The paper reports on 9 species of lichens and lichenicolous fungi collected in the Bunger Oasis (East Antarctica).