240 



Journal of Agricultural Research vol. xx. No. 3 



As a result of this steady evaporation of the paraformaldehyde from 

 these seeds those spread the longest before sealing had the smallest 

 quantity on them when put in the bottles, while those sealed earlier had 

 increasingly greater quantities. Since evaporation of the solid would 

 continue to a certain extent after the seeds were in the bottles, it would 

 seem plausible that the concentration of formaldehyde gas in the atmos- 

 pheres of the sealed bottles would vary, being greatest where seed had 

 previously dried for but a few hours and least where it had had a longer 

 time to dissipate into the air before sealing. It follows that the seed 

 injury in each bottle is proportionate to the quantity of paraformalde- 

 hyde left on the seed at the time of sealing, which, upon evaporation in 

 the bottle, cannot escape and is held around the seed. 



SUSCEPTIBILITY OF OTHER GRAINS TO POST-TREATMENT INJURY 



In laboratory experiments it was found that barley is much less sensitive 

 than wheat to dry-storage injury after treatment with ao. 1 percent solution 

 and often escapes injury altogether. Retardation or a slight lowering of 

 the germination percentage usually results, however, from drying the 

 seed in bulk or from sowing it in dry soil. In experiments where the seed 

 was allowed to lie in dry soil for varying intervals one experiment showed 

 rather severe injury, while the two repetitions showed none at all. If 

 a 0.2 per cent solution or a 4.5 per cent solution is used the characteristic 

 cumulative post-treatment injury occurs markedly, just as in wheat. 

 The latter strength is especially destructive when the seed dries (Table 

 XII). The germination percentages shown in Table XV (on blotters, 

 with one exception) are typical of the results obtained in the laboratory 

 when Coast barley was dried in tumblers after treatment. 



Table XV. — Percentage of germination shown by Coast barley when dried in the labora- 

 tory after formaldehyde treatment 



Length of drying period. 



0.1 per cent 

 solution. 



Exp. 1. Exp. 



y 2 hour 94 



7 days 90 



2 1 days 84 



42 days 84 



56 days 88 



70 days a 76 



92 

 94 



So 



0.2 per cent 

 solution. 



Exp. i. Exp. 2. 



92 



74 

 82 



3 2 



70 

 34 



04 

 86 



5 2 

 40 



4-5 per 

 cent so- 

 lution, 

 Exp. 2. 



5 2 



6 



Control, 

 untreated. 



Exp. 1. Exp. 2 



96 

 90 

 90 

 92 

 90 



90 



88 



90 

 92 



° Germinated in soil. 



The presence of the glumes on the barley grains probably affords the 

 protection which makes them more resistant than wheat to the harmful 

 effects of treatment and subsequent drying. 



