RESPIRATION AND OXYGEN. 



53 



AIR-CONTENT OF PLANTS. 



Aim^ (1841 : 537) analyzed the bubbles on the surface of marine 

 algse, such as Ulva, as well as those in the interior, with the results 

 shown in table 18. 



Table 18. 



Unger (1854) determined that the floating leaves of Pistia texensis 

 contained the maximum amount of air, 71.3 per cent by volume, while 

 the fleshy leaves of Begonia hydrocoiylifolia showed the least, 3.5 

 I per cent. 



Faivre and Dupr^ (1866) investigated the composition of the in- 

 ternal air in the organs of the mulberry under various conditions, 

 with the results shown in table 19. They found that the carbon 

 dioxid diminished and the oxygen increased as activity was reduced, 

 and that the amount of oxygen was less and of CO2 greater in roots 

 than in branches during the growing-season. 



Table 19. 



Heintz (1873 : 358) analyzed the composition of air inside the 

 sugar-beet with the results given in table 20. 



Table 20. 



