Nov. i, 1920 



Effect of Drying Disinfected Seed Wheat 



225 



Some of the same machine-thrashed Little Club seed used in all these 

 experiments was treated with a 0.1 per cent solution, and, after the sur- 

 plus liquid was removed by spreading on towels for a half hour, the seed 

 was divided into n lots, each lot nearly filling a rectangular glass dish 

 6 by 8 cm. and 3 cm. deep. One of these dishes of wheat was then placed 

 in each of the 1 1 desiccators containing 100 cc. of their respective sul- 

 phuric acid and water mixtures. These solutions were changed at the 

 end of the first, second, third, fifth, and tenth days, so that they were 

 kept at the proper strength. Samples of wheat were removed after 

 various intervals, and the injury was determined by germinating on blot- 

 ters at room temperatures. 



Table VII. — Relation between seed injury from drying after treatment with a 0.1 per 

 cent formaldehyde solution and the humidity of the atmosphere 



Specific gravity of sulphu- 

 ric acid and water mix- 

 tures. 



Ap-. 

 proxi- 

 mate 

 per- 

 cent- 

 age of 

 hu- 

 midity 

 pro- 

 duced 

 in des- 

 icca- 

 tors 



cj. 



Percentage of germination after storage in desiccators for — 



day. 



days. 



5 

 days. 



days. 



days. 



16 



days. 



22 26 

 days. days. 



28 

 days. a 



days. 



OOO 1 OO 



070 90 



130 80 



206 70 



273 60 



334 5° 



400 40 



47° 3° 



53° 20 



604 10 



840 o 



Control 



98 

 96 

 94 

 96 

 96 



96 

 94 

 96 

 96 



94 

 98 

 96 

 96 

 98 

 96 



94 



98 



92 



100 



94 

 96 

 92 

 90 



74 

 84 



«4 



9 S 

 96 



94 

 90 

 90 

 82 

 70 

 74 

 84 

 80 



<5> 

 ( b ) 



94 

 96 



82 

 76 



76 



So 



( b ) 

 96 

 90 

 96 

 88 

 74 

 78 

 80 



(b) 



( b ) 



( 6 ) 

 98 

 90 

 86 

 78 

 70 

 84 

 72 

 82 

 96 



( b ) 



( b ) 



( 6 ) 



90 



96 

 92 



82 



b ) 

 b ) 



( b ) 

 88 

 86 

 94 

 74 

 72 

 70 

 72 

 64 



100 



( 6 ) 

 ( 6 ) 

 100 



92 

 88 

 82 

 76 



72 

 76 

 86 

 96 



a Germinated in soil. 

 b Attacked by molds. 



A study of these germination percentages reveals several most interest- 

 ing facts. It is at once obvious that they show the existence of a close 

 relationship between the seed-treatment injury caused by drying and the 

 humidity of the atmosphere. They show that there is no injury in the 

 damper atmosphere of 70 per cent humidity and above, so long as the 

 seed is not attacked by molds. They show also that there is less injury 

 in the dryest desiccators, those containing from 20 per cent moisture to 

 none at all, than in those of intermediate humidities. These compara- 

 tive injuries are made clearer by a graph (fig. 2) the points on which 

 represent the averages of all the percentages obtained for each sample, 

 beginning with those obtained after five days' storage. The data for the 

 9507°— 20 5 



