Fankhauser, HeinzHeinzFankhauserBrunold, ChristianChristianBrunoldErismann, Karl HansKarl HansErismann2025-01-082025-01-081976https://boris-portal.unibe.ch/handle/20.500.12422/199544There was no disturbance in the growth of Lemna minor L. with a SO2 concentration of up to 0.3 ppm in air. A SO2 concentration of 0.6 ppm caused an initial depression of the growth rate of about 25%, but in the course of adaptation, the rate rose to the values of the control. The average dry weight per frond was not influenced by the SO2 fumigation. The initial sporadic appearance of chloroses by fumigation with 0.6 ppm SO2 was considered a sign of the proximate toxicity limit for Lemna minor L. With 0.15 ppm SO2 in air, the size of the fronds was reduced. The average surface of the fronds was diminished by 0.3 ppm SO2 for about 16% as compared with the control plants. The protein remained quantitatively uneffected up to a SO2 concentration of 0.6 ppm. As a qualitative influence of SO2, the nitrogen content of the proteins remained constant, but the sulfur content of the proteins increased. Under 0.3 and 0.6 ppm SO2, the starch content decreased immediately by 20–30%, under 0.15 ppm SO2 the decrease reached the same level after a longer time than in the case of the higher concentrations.enstarchchlorophylldepressionnitrogen contentproduct yield500 - Science::580 - Plants (Botany)article10.7892/boris.10734110.1007/BF00361236