Influence of Certain Carbohydrates on Green Plants 45 



It was found that saccharose, glucose, fructose, galactose, maltose, and 

 lactose increased the amount of carbon dioxide evolved. Lactose was but 

 slightly effective in this respect, while arabinose was apparently without 

 any influence. The respiratory quotient was increased notably by 

 saccharose, less by glucose or fructose, and only very slightly by the other 

 sugars. In cultures supplied with either saccharose, glucose, or fructose, 

 alcohol was formed as a product of respiration. It could be detected by 

 its characteristic odor when the nutrient solution was distilled or the 

 germinated embryos were heated. 



Fig. 7. respiration apparatus 



It is clear, therefore, that sugar may be absorbed by leaves and shoots, 

 and that the sugar absorbed increases respiration. The experiments 

 just described, however, afford no information as to the continued effect 

 of the sugars either on respiration or on growth. With the view of solving 

 these two problems, and also of determining the period when the initial 

 assimilation of the sugar occurs, the investigation here described was 

 undertaken. 



The growth chambers used in this experiment consisted of eight 2-liter 

 suction flasks, shown in figure 8. Each culture chamber was fitted with 

 a two-holed rubber stopper. Through one of the holes was inserted a 

 thermometer, and through the other a glass tube extending to within a 



