22 



Lewis Knudson 



there is a slight difference in the individual cultures of each sugar in the 

 distribution of growth. A very notable increase in dry weight is manifest 

 in all the sugar-fed plants. Indeed, when supplied with sugar the dry 

 weight of the plants is in most cases approximately double that of the check 

 plants. Glucose appears to be the most effective, followed bj^ fructose, 

 saccharose, and maltose in the order given. No effect was noted of the 

 sugars on the use of the endosperm reserve. Unfortunately the dry weight 

 was obtained from onlj^^ one of the check cultures, the plants of the other 

 check being accidentally lost. The general appearance of the latter was 

 very similar to the first check culture, as is indicated by the figures for 

 average length of tops. The influence of the sugars is seen in figure 2. 



TABLE 1. Influence of Various Sugars on Growth of Corn 



(Plants grown in greenhouse. Duration. December 20 to January 19, 1914, thirty days. 

 Origing.1 weight of seed, 0.296 gram ± 10 miUigrams) 



Culture solution 



Number 



of 

 plants 



Average j^^^^ 



length • ■; , 

 J. ,* weight 



?'*°>?' 1 of tops 



1 



Dry 



weight 

 of root-s 

 (grams) 



Total 



dry 



weight 



(grams) 



Average 



weight 



per 



plant 



(grams) 



Check (no sugar) / ^ 



Glucose, 2 per cent i ^ 



Fructose, 2 per cent J 1 



Maltose, 2 per cent i ^ 



Saccharose, 2 per cent i ^ 



4 

 4 

 4 

 4 

 4 

 4 

 ' 4 

 4 

 4 

 4 



39.5 

 39.0 

 40.2 

 38.0 

 49.0 

 53.5 

 46.0 

 52.0 

 51.5 

 47.0 



'6'535 

 0.989 

 0.958 

 1.078 

 1.005 

 0.794 

 0.802 

 0.976 

 0.830 



'o'343 

 0.773 

 0.735 

 0.672 

 0.695 

 0.479 

 0.444 

 0.531 

 0.695 



0.878 

 1.762 

 1.693 

 1.750 

 1.700 

 1.273 

 1.246 

 1.507 

 1.525 



" 0.219 

 0.440 

 0.423 

 0.437 

 0.425 

 0.318 

 0.311 

 0.377 

 0.381 



IX THE DARK 



' The data for the plants grown in the laboratory in the dark are given 

 in table 2. In aU cases the average length of the tops is greater in the 

 sugar-containing cultures than in the check cultures. The same is true 

 of the dry weights; in the presence of sugar the plants not onh^ made con- 

 siderable growth, but approximately maintained their original dry weight. 



