Nov. i, 1920 



Effect of Drying Disinfected Seed Wheat 



227 



evidence of some deleterious effect of the treatment. There is a very 

 definite point of maximum injury — the 70 per cent humidity. This 

 is somewhat different from the situation in the preceding experiment, 

 where the maximum injury was at approximately 30 per cent humidity, 

 with none at all occurring at 70 per cent. 



Table VIII. 



-Data from the second experiment on the relation between humidity and 

 seed injury after formaldehyde treatment 



Specific gravity of sulphuric 

 acid and water mixtures. 



Ap- 



proxi- 

 mate 

 per- 

 centage 

 of hu- 

 midity 

 pro- 

 duced 

 in des- 

 icca- 

 tors 



(2°°C). 



Stored 10 days. 



Germi- 

 nation. 



Height 



of 

 plants." 



Stored 21 days. 



Germi- 

 nation. 



Height 



of 

 plants." 



Stored 35 days. 



Germi- 

 nation. 



Height 



of 

 plants." 



Stored 42 days. 



Germi- 

 nation. 



Height 



of 

 plants." 



I. OOO 



I-I30 



I.206 



1-273 



1-334 



1.400 



i-53° 



1.604 



1.840 



Control 



100 

 80 



7° 

 60 



5° 

 40 

 20 

 10 



Per ct. 

 96 

 94 

 6 

 18 

 96 

 90 

 90 

 98 

 96 

 98 



Cm. 



5 

 5 



Per ct. 



98 



IOO 



4 

 38 

 70 

 84 



IOO 



Cm. 

 8.0 

 7.0 

 I. o — 

 I. o— 

 I. o 



i-5 

 5° 

 4.0 

 6.0 

 7.0 



Per ct. 



Cm. 



20 



45 

 80 

 90 

 80 

 100 



IOO 



Per ct. 



Cm. 



92 



88 



1. 0- 

 1. o- 



i-5 

 i-5 

 3-5 

 3-5 

 3-5 

 6.0 



"The average heights of the plumules after 6 days are given for each germinating sample, because a 

 comparison of these for all the samples of any one test shows any injury indicated by retardation which 

 sometimes would not be shown by the germination percentage alone. A height of less than one centi- 

 meter (1 — ) indicates extreme injury, with usually stunted, deformed plumules which could not reach 

 the surface of the soil. 



Figure 3 shows more plainly the comparative germinations given in 

 Table VIII. As in figure 2, each point was obtained by averaging all 

 the germination percentages given by the sample stored at each indicated 

 humidity. 



Since all germinations were made in blotters without temperature or 

 humidity control, the rate of growth of seedlings of successive 6-day 

 germinations of the same sample varied in a meaningless way and so 

 were valueless except for comparisons of the injury shown by the dif- 

 ferent samples in the same germination test. However, as noted in the 

 discussion of the first experiment with the desiccators, the growth meas- 

 urements follow closely the germination percentages and are more deli- 

 cate indicators of harmful effects of treatment than the latter. 



If the averages of the heights of the seedlings from each desiccator 

 for all the germination tests of both experiments be plotted with the 

 humidities in which the respective seed samples were stored, a graph 

 such as figure 4 is obtained. These heights were measured after six and 

 seven days' growth, but the conditions of germination in successive 



