Influence of Certain Carbohydrates on Green Plants 21 



on the dry weight of the plants. The variety of corn used was a yellow 

 dent. All the grains were selected for uniformity of shape and weight, 

 and all came from the same ear. 



As culture vessels the large cylinders, 63 by 10 centimeters in size, 

 were used, and in each was placed the nutrient solution plus 1.2 per cent 

 of agar. Two-per-cent concentrations of the various sugars were used. 

 These solutions are approximately equivalent as regards carbon, but 

 differ as regards their osmotic relationships. The hexose sugars would 

 have the higher osmotic pressure, since a 2-per-cent solution has a gram 

 molecular concentration of 

 0.111 while the molecular con- 

 centration of the 2-per-cent 

 disaccharide solutions is 0.058. 

 Subsequent experiments and 

 the work of MolHard (1907) 

 indicate that concentrations of 

 sugar much higher than that 

 of the hexose cultures are more 

 favorable to the growth cf 

 plants than the weaker concen- 

 tration. In fact, in an experi- 

 ment subsequently reported, 

 6.4 per cent of glucose shows 

 a more favorable influence than 

 2 per cent of glucose. The 

 higher molecular concentration 

 of glucose as compared to sac- 

 charose, then, should not be 

 injurious to the growth of 

 corn. On the other hand, this 

 increased concentration might 



account tor the greater value ^iq. 2. influence of sugars on growth of corn 

 of the hexose sugars in increas- 

 ing growth. 



IN the light 



The results obtained from the cultures grown in the light are given in 

 table 1 . The results for each of the different sugars are consistent, though 



62, Glucose; 66, fructose; 69, saccharose; unnumbered, 

 check (no sugar) ; 65, maltose 



