62 



STUDIES IN PLANT RESPIBATION AND PHOTOSYNTHESIS. 



in the carbohydrate-content, although d-levulose is notably a good 

 nutrient for starch-forming plants. The rates of respiration are 

 given in table 41 and figure 16. 



Table 44. 



The preceding experiment was repeated, all conditions remaining 

 the same, except that the nutrient solution contained, besides the 

 d-levulose, 0.11 per cent of glycocoll. The analyses of the leaves 

 are compiled in table 42. 



Table 45. — Rate of emission of CO2 hy 7 leaves of Helianthus annuus at 25°. 

 Petioles in nitrogen-free nutrient solution containing 7 per cent d-levulose and 0.138 per cent 

 asparagine. CO2 absorbed in Ba(0H)2 solution. Nos. 1 to 8, inclusive, in solution 0.11835 

 normal, 125 c. 0. of which has the CO2 equivalent of 0.3254 gram CO2. Nos. 9 to 13 in solution 

 0.12153 normal, 125 c. c. of which has the CO2 equivalent of 0.3343 gram, CO2. 



The rates of respiration for this experiment are given in table 43 

 and in the graphs in figur.e 16. 



The experiment was again repeated, the glycocoll being replaced 

 in this instance by asparagine. The analytical data are presented 

 in table 44. 



The rates of respiration are shown in table 45 and in the graphs 

 in figure 16. 



