STUDIES IN PLANT RESPIRATION AND PHOTOSYNTHESIS. 



49 



conditions in which there is a decided increase in the carbohydrate- 

 content of the leaves and but a shght increase in amino-acids. In 

 the following experiment, carried out with Canada Wonder bean 

 leaves, the experimental conditions were the same as in the two 



50 35^ 40 4S SO 5S 60 6S 70 75 80 85 90 95 



Figure 11. 

 Rate of respiration of 6 leaves of Helianthus annuus at 25°; petioles in nitrogen- 

 free nutrient solution containing 7 per cent d-glucose. The ordinate represents mg. 

 CO2 per hour per gram dry material, the abscissa the time in hours. 



previous experiments, i. e., the petioles of the leaves were in a 

 nitrogen-free nutrient solution containing 7 per cent glucose, and the 

 CO2 emission was determined in the dark at 25°. From the analytical 



Table 26. 



data in table 26 it is evident that there was a decided increase in 

 the carbohydrate-content, but only a slight increase in the amino 

 acids. The rates of respiration are given in table 27 and figure 12. 



