Effects of temperature and light on the lipids of Sphagnum magellanicum

Abstract

The growth, lipid, protein and chlorophyll contents and fatty acid composition changes in polar lipids were studied in the moss Sphagnum magellanicum cultured aseptically under different light and temperature conditions. In dim light, changes in growth and the amounts of the studied organic components were larger than in darkness. The lipid and chlorophyll a and b amounts increased in dim light, while the actual growth declined. The chlorophyll a/b ratios increased slightly when the light decreased. In normal light, temperature decrease was accompanied by a decrease in the amounts of linolenic acid and a corresponding increase in the amounts of palmitic acid in the glycolipids. When the change in temperature was combined with a change in light, decreasing light and temperature was accompanied by a decrease in linolenic and a reverse reaction for palmitic acids in the glycolipids. Often no linear pattern of change in the glycolipid fatty acids could be seen, and no profound unsaturation/saturation changes occurred. When the temperature change was combined with a corresponding change in the length of the light period (in normal light), the optimum conditions for the formation of linolenic acid appeared to be 15° and 12 hr/light, although no clear patterns of change were seen regardless of the glyco- or phospholipid studied. The largest deviations from the ‘normal’ fatty acid composition under these conditions were seen generally at lower temperatures (0–5°) and shorter periods of light (–6 hr light/day).