Influence of Certain Carbohydrates on Green Plants 29 



EXPERIMENTS WITH RADISH (RAPHANUS SATIVUS L.) 

 Radish has been used in experiments by Molhard (1907) and by Ravin 

 (1913). Molliard concluded that radish is able to utilize glucose some- 

 what better than fructose. Maltose is much like glucose in its effect. 

 The following figures from Molliard show the effect of various culture 

 solutions on dry weight of radish: 



Culture solution 



Dry weight 

 (milligrams) 



Knop solution alone 



Knop + 5 per cent of glucose . . . 

 Knop + 5 per cent of saccharose. 



42- 60 

 109-133 

 102-125 



Molliard states also that 9.5 per cent of maltose had the same effect as 

 5 per cent of glucose, with which it is isotonic. The work of Ravin on 

 the influence of glucose and organic acids on radish has already been 

 mentioned. 



influence of approximately carbon-equivalent solutions 

 The variety of radish used in these experiments was the common garden 

 variety. The seeds were carefully selected for uniformity of size. As culture 

 vessels liter flasks were employed, each containing 200 cubic centimeters 

 of the culture medium (Fig. 3). The seeds were sterilized by immersion 

 in the calcium hypochlorite solution for a period of five hours. Fourteen 

 cultures were set up for each series, and in each flask two seeds were 

 sown. Not all the seeds germinated. In some cultures two plants, 

 and in others only one plant, developed. The latter condition was par- 

 ticularly true for the check series of cultures; it may be that the sugar 

 in the nutrient solution increased the percentage of germination. Because 

 of the difference in germination the final results are given in two tables, 

 since, as has been heretofore stated, a just comparison cannot be made 

 between cultures having unequal numbers of plants. The. results appear 

 in tables 8 and 9: 



