1922] JONES & SHIVE—WHEAT SEEDLINGS 399 
Experience with twenty representative solutions of Torrinc- 
HAM’Ss (18) complete series of eighty-four, modified as here described 
by substituting ammonium sulphate for the potassium nitrate in 
equivalent osmotic concentrations, has shown that the Py values 
of these solutions are not greatly altered by contact with the roots 
of young wheat plants between the ages of four and five weeks, 
the tendency always being toward a slight increase in the H ion 
concentration of the solutions during growth intervals of three or 
four days without renewal of the solutions. It is thus easily seen 
that for certain types of culture studies in which it is desirable 
to maintain the H ion concentrations of the nutrient media within 
comparatively narrow variation limits, solutions of this kind possess 
marked advantages over those in which the H ion concentrations 
are rapidly decreased by the action of the plants. The two solu- 
tions (modified TorrmscHam solutions T,R,C; and T,R;C;) have 
the added advantage of high efficiency in the production of young 
wheat plants when iron in small amounts is supplied to the solutions 
in an insoluble form such as ferric phosphate. Soluble iron in the 
form of ferrous sulphate, even in small traces, has been shown (6) 
to be exceedingly toxic to the plants grown in these solutions. 
New Jersey AGRICULTURAL EXPERIMENT STATION 
EW Brunswick, N.J. 
LITERATURE CITED 
1. Brrner, H., and Lucanus, B., Wasserkulturversuche mit Hafer in der 
Agric.-Chem. Versuchsstation zu Regenwalde. Landw. Versuchsst. 
8:128-177. 1866. 
2. Crone, G., Ergebnisse von Untersuchungen iiber die Wirkung der Phos- 
phorsiiure auf die héhere Pflanzen und eine neue Niahrlésung. Sitzungsber. 
Neiderrhein. Ges. Nat. und Heilk. Bonn. 1902 (pp. 167-173). 
Deter, W., Practical plant physiology, translated by S. A. Moor. 
London. 1898 (p. 2). 
. GILLEsPrE, L. J., Colorimetric determination of hydrogen-ion concentra- 
tion without buffer mixtures, with especial reference to soils. Soil Science 
9: 115-136. 1920. 
HartweLt, B. L., WHEELER, H. J., and PemBer, F. R., The effect of the 
addition of sodium to deficient amounts of potassium upon the growth of 
plants in both water and sand cultures. Ann. Report Rhode Island Agric. 
Exp. Sta. 20:299-357. 1907. 
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