86 



PROTECTION OF PLANTS — 1923-24 



TABLE III. 



Effect of Temperature of Treatment Solution. 



There was no appreciable reduction in germination of any of the hulled 

 varieties, either with a low or high temperature of solution. With the Liberty- 

 oats there was a gradual decrease in the percentage of germination as the tem- 

 perature of the formalin solution was increased. 



Efifect of Carbon Dioxide on Germination of Treated Seed. 



The fact that seed germinated in an atmosphere of carbon dioxide, are 

 retarded or reduced in their germination has long been known. The present 

 experiment was carried out to determine whether formalin seed were more 

 injured than untreated seed when germinated in an atmosphere of 50 per cent 

 carbon dioxide and 50 per cent air. 



Samples of Banner, a hulled variety, and Liberty, a hull-less variety were 

 taken and treated for ten minutes in a solution of formalin of 1 pint to 40 

 gallons (1:40). The control samples were dipped in tap water for the same 

 length of time. 



The treated and the untreated samples of seed were placed to germinate 

 on pieces of wet blotting paper, in the bottom of petri plates. The petri plates 

 were floated in the sink partially filled with water. Over these was inverted a 

 graduated bell-jar. The air inside the jar was adjusted to 3 litres by means of 

 water displacement. Carbon dioxide was then generated and added to the 

 bell-jar by means of a rubber tube placed under the bell-jar beneath the water. 

 The carbon dioxide was then allowed to enter into the jar until the water 

 was driven down to the 8 litre mark. This atmosphere, of half carbon dioxide 



