Influence of Certain Carbohydrates on Green Plants 39 



above the surface of the nutrient solution (Fig. 5). The seeds were 

 selected for uniformity of shape and size, each having a dry weight of 29 

 milligrams. They were sterilized in the usual way and two seeds were sown 

 in each cyhnder. The cultures were made in quadrupHcate. The con- 

 centration of sugar employed was in all cases approximately 1 per cent. 

 Owing to delayed germination of some of the seeds, to failure of germina- 

 tion of others, and to contamination in a few cultures, only one-half of the 

 cultures were available for comparison. The sugars were determined by 

 the Ahllin modification of the Fehhng method. The disaccharide sugars 

 were hydrolyzed and the reducing values were then determined. The 

 results obtained are presented in table 15: 



TABLE 15. Influence of Various Sugars on the Growth of Vetch in Water 



Cultures 



(Duration, January 19 to February 27, 1915, thirty-nine days) 



Culture solution 



Num- 

 ber 

 of 

 plants 



Dry 



weight 

 of 

 roots 

 (milli- 

 grams) 



Dry 



weight 

 of 



tops 

 (milli- 

 grams) 



Total 



dry 



weight 



(milli- 

 grams) 



Gain in 

 weight 

 (milli- 

 grams) 



Aver- 

 age 

 dry 

 weight 

 per 

 plant 

 (milli- 

 grams) 



Gain in 

 weight 

 per 

 plant 

 (milli- 

 grams) 



Sugar 



ab- 

 sorbed 

 (milli- 

 grams) 



fl 

 Check (no sugar) . . . -^ 2 



13 

 Lactose 



2 

 2 

 1 

 1 

 2 

 1 

 1 

 2 

 1 

 2 



13 

 15 

 8 

 16 

 41 

 30 

 20 

 39 

 55 

 77 



67 

 68 

 32 



40 

 81 

 62 

 42 

 75 

 60 

 96 



80 



83 



40 



56 



122 



92 



62 



114 



115 



173 



22 

 25 

 11 

 27 

 64 

 63 

 33 

 56 

 86 

 115 



40.0 

 41.5 

 40.0 

 56.0 

 61.0 

 92.0 

 62.0 

 57.0 

 115.0 

 86.5 



11.0 

 12.5 

 11.0 

 27.0 

 32.0 

 63.0 

 33.0 

 28.0 

 86.0 

 57.5 



49 



Glucose < 2 



Maltose 



72.6 

 66.5 

 24 4 



Fructose 



f *1 

 Saccharose < j..^ 



113.0 

 133.4 

 141.0 



* 151 milligrams of reducing sugar present, 

 t 125 milligrams of reducing sugar present. 



In every case there is a marked increase in yield when sugar has been 

 supplied. The results are not conclusive, however, with respect to the 



