[Gas exchange determinations of Sphagnum Magellanicum : A contribution to the problem of membrane pigments in sphagna (III)].

Sphagnum magellanicum shows a remarkable variation in colour after the repeated application of cold shocks; mainly red wall pigments are synthesized. An attempt was made to find out in which way the gas exchange of Sphagnum magellanicum under defined conditions is altered after the application of cold shocks.The light-intensity curve of Sphagnum magellanicum cultivated under defined conditions shows no saturation at 8000 lx (0.03 Vol.-% CO2); the compensation point was found to be 400 lx and the optimal temperature 18°C.The O2-uptake of Sphagnum magellanicum drops at 3°C to 10% of the 20°C value.Whereas the oxygen-uptake by Sphagnum magellanicum is not altered by repeated cold shocks during the dark periods the photosynthetic rate is significantly depressed.