17, 6 Trelease: Salt Requirements of Wheat Plants 565 
data go, it appears that Tottingham’s best solution gave a some- 
what higher top yield than did Shive’s in series I, while this 
relation was reversed in series II. On the whole, however, the 
best three salt proportions seem to be about the same in their 
ability to produce dry top yields under the aérial conditions of 
both these series. 
As has been said, the salts used in the present study are the 
same as those of the solution that has come to be known as 
Detmer’s solution.** This contains the four salts in the follow- 
ing proportions: 0.0130 M calcium nitrate, 0.0039 M monopotas- 
sium phosphate, 0.0044 M magnesium sulphate, and 0.0072 M 
potassium chloride. These exact proportions were not tested in 
the present work, but there were two solutions, in both series I 
and series II, the proportions of which closely resembled those 
used by Detmer. These were T2R1C6 and T3R1C5. These two 
solutions resembling Detmer’s gave only 81 and 85 per cent of the 
top yield obtained with the best proportions in series I (solution 
T2R4C2); and these same solutions gave only 77 and 81 per 
cent of the top yields obtained with the best proportions in 
series II (solution T2R42C1#%). In series 1, at least thirty of the 
eighty-four solutions tested gave higher yields of tops than were 
obtained with the solutions closely resembling Detmer’s in salt 
proportions. An even more marked improvement over the 
growth obtained with Detmer’s exact proportions is reported by 
Shive for his best three-salt solution which, as has been men- 
tioned, gave practically the same yield as did the best four-salt 
solution used in this study. ee 
Regarding the production of root yields, the same generaliza- 
tions appear to hold for series II as were stated for series I; 
and the general correspondence between high and low root areas, 
on the one hand, and between high and low top areas, on the 
other hand, seems to be more definite in the latter series. The 
salt proportions giving the lowest root yields were the same in 
both series (T1R1C1), and these same proportions also gave 
lowest top yields in both. In series II the highest root yield 
occurred in culture T2R3$C34, which had nearly the same salt 
proportions as the culture giving highest root yields in series 
I (T8R8C38). 
”Detmer, W., Practical Plant Physiology. Translated by S. A. Moor. 
London (1898) 2. 
