Influence of Certain Carbohydrates on Green Plants 25 



Here again it is noted that all the sugars exert a beneficial effect on the 

 plants. In this case saccharose is the most beneficial, glucose and maltose 

 are somewhat similar, and lactose is of the least benefit. No conclusions 

 can be drawn with respect to the conservation of the reserve food of the 

 cotyledons because of the sugar supplied. 



. EXPERIMENTS WITH TIMOTHY (PHLEUM PRATENSE L.) 

 A considerable number of experiments were made with timothy, but 

 most of the data are not included for the reason that the results obtained 

 were not concordant. This was due to the fact that a constant number of 

 plants could not be maintained in the culture vessels, owing to the difficulty 

 of introducing a uniform number of seeds and to variation in germina- 

 tion. Various tests showed that there is a relation between the number of 

 plants in the culture vessel, and growth of the plants. The greater the 

 number of plants in the culture vessel, the less is the growth of the individual 

 plants therein. Experiments indicate that the limiting factor is a supply 

 of carbon dioxide. 



In the following experiments with timothy the plants were grown in the 

 large test tubes. In each tube was placed exactly 50 cubic centimeters 

 of the culture solution containing 1.2 per cent of agar. The seeds were 

 sterilized in the usual manner. The duration of growth varied in the 

 different experiments. • 



CULTURES IN LIGHT 



In this experiment the influence of 2-per-cent solutions of glucose, 

 maltose, and saccharose was to be noted. Unfortunately the maltose and 

 the saccharose cultures became contaminated. Likewise unfortunately 

 for accurate results, the same number of plants was not present in each 

 culture. Since, however, there are fewer plants in the check than in 

 the glucose cultures, the beneficial effect of glucose is in reality greater 

 than the dry-weight figures indicate. The plants grown in the presence 

 of glucose showed a more vigorous appearance than did the check plants. 

 Also, the plants in tjie presence of glucose showed at the base of the stalk 

 a markedly red coloration, which disappeared after the plants had been 

 kept in the laboratory for a week. The results obtained are given in 

 table 4. In another experiment it was noted that asparagin could serve 

 timothy as a source of nitrogen. 



