70 Lewis Knudson 



10. The carbon dioxide evolution of the sugar-fed plants during the 

 daji^inie is always appreciablj^ greater than that of the check cultures. 

 This is due in part to a greater root development in the sugar-fed cultures, 

 but also to a greater rate of respiration. 



11. Cabbage {Brassica oleracea L.) grown in the presence of maltose 

 shows increased growth. The higher the concentration (2.5 per cent being 

 the highest concentration emploj^ed), the greater is the jneld of drj^ matter. 

 A mixture of saccharose and maltose increased gro-^i:h to a greater extent 

 than 2 per cent of maltose alone. 



12. Sweet clover (Melilotus alha Desr.) increases its gro-^^h -^nth 

 increased concentration of glucose or saccharose. Crimson clover (Tri- 

 foUum incarnatum L.) behaves similarly when provided with maltose. 



13. Vetch {Vicia villosa Roth) shows increased growth with increase in 

 concentration of sugar. 



14. Vetch (Vicia rillosa Roth) is shown to absorb glucose from an 

 extremely weak solution. 



15. The sugar galactose is toxic to vetch, Canada field pea, corn, and 

 wheat, even at concentrations as low as 0.0125 per cent. 



16. The toxicity of 0.05 gram molecular galactose for Canada field 

 pea is antidoted almost entirely by glucose when present at a concentra- 

 tion of 0.10 or 0.20 gram molecular. The toxicity of this solution of 

 galactose is partially antidoted by 0.05 molecular glucose, but practically 

 not at all antidoted when the glucose is less than 0.05 gram molecular. 



17. The antagonistic action of glucose toward galactose may be due 

 to its rendering the root impermeable to galactose. It is suggested that 

 the toxicity of galactose may be due to its oxidation products, and that in 

 the presence of glucose the metabohsm of galactose may be altered. 



18. Evidence was obtained indicating the inversion of saccharose by 

 the roots of vetch, Canada field pea, radish, and sunflower. The inversion 

 was due to invert ase probably secreted from the roots. No secretion of 

 maltose or lactose was noted. 



19. In the presence of sugar there was noted a marked development of 

 pigment in corn and in vetch. 



ACKNOWLEDGMENTS 



The writer is indebted to Dr. J. K. Wilson, of Cornell University, for 

 assistance in some of the early experiments, and to Dr. C. S. Hudson, in 



