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Experimental Studies on the Physiology of the Phycobiont and Mycobiont Ramalina ecklonii By
Author(s) -
Fox Cecil H.
Publication year - 1966
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1966.tb07071.x
Subject(s) - fungus , incubation , thiamine , biology , algae , botany , lichen , incubation period , hypha , dry weight , spore , food science , biochemistry
The lichenized fungus and alga of the fruticose lichen Ramalini ecklonii were isolated into pure cultures. The ascospores of the fungus failed to germinate in less than five weeks incubation in spite of the use of a variety of cultural conditions. The fungus showed a considerable increase in growth on malt extract agar. Both organisms showed a marked tolerance for high concentrations of glucose although growth was quantitatively reduced. The fungus was able to use a variety of carbon and nitrogen sources as well as an extract of algal cells. Cultivation in the absence of biotin and thiamine failed to yield significant amounts of growth. The alga yielded 27 mg of dry weight after three weeks in a synthetic medium under low light intensities. The alga could be grown in satisfactory amounts on CO 2 and inorganic salts with moderate light intensities. Experiments using 14 CO 2 showed the fungus able to incorporate the extra‐cellular and intra‐cellular products of algal metabolism. The rate of incorporation of extra‐cellular products was inhibited by high concentrations of biotin and thiamine. The alga assimilated l4 CO 2 which was retained by the cells over a period of 14 days, at which time 78 per cent of the activity was insoluble in 80 per cent ethanol. An extract of the fungus labelled with 14 C glucose was partially taken up by the alga and 50 per cent of the label was insoluble in 80 per cent after three days incubation in the light. No lichen acids were found in either the fungal cultures or the algal cultures although large amounts ( e.g . 2 liters) of material were extracted and chromatographed. Usnic acid was produced by the intact lichen thallus.