— 238 — 



4. The production of matter in light plants. 



Let us turn to the estimation of the production of matter in 

 light plants in the manner described above. After some preliminary 

 investigations I chose the 4 following plants for my experiments, 

 viz. Sinapis alba, Senecio silvaticus, Rumex acetosella and Sambucus 





























""S 



b 



























«1 



















* 









1 



























1 





































































































Mensity 





P 





1 



2 / 



s 2 



0 2 



f- 2 



3 3 



2 J 





o * 



<f * 



3 52 





























Fig. 3. C0 2 assimilation in Sinapis alba. 



nigra. The plants used in my experiments were all grown in full 

 daylight. 



1. CO 2 assimilation. The results of the estimations of the 

 C0 2 assimilation in the 4 plants are printed in Tables I — IV. 

 As mentioned above the different estimations are reduced to a 

 temperature of 20° and a C0 2 tension of 0.55 mg per 1. The figures 

 are recorded as curves in fig. 3 and 4. In the curves the abscissae 

 indicate the intensity of light in Bunsen's units X 100 and the 

 ordinates the C0 2 assimilation in mg per hour per 50 cm 2 of the 

 upper surface + 50 cm 2 of the lower surface. 



' For Sinapis alba (fig. 3) the different estimations are marked 

 out. As it might be expected the variability is rather great. The 

 reason is partly, that the error in the estimations as mentioned 



