1920] 
DUGGAR—H-ION CONCENTRATION AND NUTRIENT SOLUTIONS 25 
" 
Teal green wi, 
"eren | ear 
^— Sol. Mand 6) 
| SLA dpi ra 
ot. C (Hda)_ 
Sol. e. Wr» 
8 4 
7 
: 
¿Base And, i glides a 
5 > SS ad festus Y 
/ \ 
V Pd 
Y 
\ 
X 
X 
y 
\ j Bess dine, Sols. A and B (10 as.) 
4| \/ 
3 
1 
aL...) \ Base line, Sels A ye 
/ 
ee Cae ee BuO Boo Bom A. Y 
P og caw dhe dip ES Se Ey Ey M S 56 u Te p 
Fig. 3. Total green weight of wheat in solutions A, B, and C, with modifications 
Hed largely by combinations of phosphates or by the introduction of “insoluble” 
buffers. Intervals between the renewal of solutions were 4 and 10 da 
ever, that in these cases the chlorosis may be related to inade- 
quate iron supply, and not to faulty proportions of the main salt 
constituents. 
The Ac h/1, Ac h/2 and Ac h/Al cultures all show the in- 
jurious effect of high acidity; but with the initial value of Py 4.8 
the best growth in the one lot is in the A solution, though practi- 
cally approached in the double strength of the B solution 
[2(BcO)]. Aside from the considerable variation in cultures 
differing only slightly in composition or in Py, the chief point 
of interest is the depressing action of the ammonium salt in both 
lots (BeNH). 
The curves, figs. 3 (wheat) and 4 (corn), exhibit diagrammat- 
ically the data above discussed, and require no explanation, 
further than to point out that the results with solution C appear 
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