1340 



INDUCTION PHENOMENA 



CHAP. 33 



before and after passage through the plant chamber. Aufdemgarten 

 studied by this method the induction in Stichococcus hacillaris. His re- 

 sults are shown in figures 33.10 and 33.11. We find in them the same three 

 features noted above in the curves of McAlister and Myers: an initial 

 guly of carbon dioxide (registered, because of the time lag of the apparatus, 

 about 15 seconds after the beginning of illumination), a gradual increase 



Fig. 33.11a. Time course of CO2 uptake by Stichococcus hacillaris (after 

 Aufdemgarten 1939). (a to d), inorganic nutrition: (a) 4 weeks light, 30 min. 

 dark, Kolkwitz solution, pH 7.6; (b) 4 weeks light, 30 min. dark, Eiler solution, 

 pH5.8, 19° C; (c) 10 days dark, Kolkwitz solution, 18.1° C; (d) 10 days dark, Ei- 

 ler solution, 18.9° C; (e) organic nutrition in daylight; 15 min. dark, 4 min. 6 

 sec. light. 



lasting for several minutes, and (in some curves) a secondary depression, 

 D2, which is registered between 1 and 1.5 minutes after the beginning of 

 illumination. As in McAlister's curves, this depression can be most clearly 

 seen on curves in which the main induction effect is weak, such as c and / 

 in figure 33.10a, and/ in figure 33.10b. 



The analogy between the carbon dioxide exchange curves of the type 

 a in figure 33.10a (or type h in figure 33.11a) and the oxygen exchange 

 curves of the type of figure 33.2 is obvious. Quantitative comparison is 

 impossible, because the oxygen curve is an integral curve, while the carbon 



