PROTECTIVE POWER AGAINST SALT INJURY OF 
LARGE ROOT SYSTEMS OF WHEAT 
SEEDLINGS 
W. F. GERICKE 
That wheat plants can be made to grow very large root systems as 
compared with the growth of their tops by certain properties of nutri- 
ent solutions, has been shown in a previous paper." T he writer has 
also shown that under certain conditions large root systems of wheat 
seedlings 4-6 weeks old play an important réle in the number of 
tillers? the plant may produce. These observations suggested fur- 
ther experimentation where differences in the extent of the root 
systems of the plants would enter as the variable factor. It seemed 
plausible to expect that the relative physiological values or growth 
efficiencies of different nutrient solutions, and the tolerance of plants 
to salts, were not inconsiderably affected by the extent of the root 
development of the test plants when placed in the media. The 
present paper bears upon an investigation on these points. 
Three different kinds of nutrient solutions were selected for the 
tests. These were solutions whose relative values as growth media ~ 
had previously been obtained. The composition, molecular concen- 
tration of the salts, and the relative physiological values of these 
solutions stated as ‘‘good,” “medium,” or ‘‘poor” were as’ follows: 
Solution no. 1.—o.0102 mol. KH.PO,; 0.0057 mol. Ca(NO;)2; 
0.0062 mol. MgSO,. Good. 
Solution no. 2.—o.014 mol. K,SO,; 0.002 mol. Ca(NO,),; 0.002 
mol. Mg(H.PO,).. Very poor. 
Solution no. 3.—o.016 mol. MgSO,; 0.002 mol. Ca(NO,)2; 0.002 
mol. KH,PO,. Poor if air temperature and transpiration for growth 
were high; medium if air temperature and transpiration for growth 
were relatively low. 
* GeRICKE, W. F., Root development of wheat seedlings. Bor, Gaz. 72:404-406. 
1921. 
2 
, Certain relations between root development and tillering in wheat. (To 
appear in Amer. Jour. Bot. 9:1922 
Botanical Gazette, vol. 74] [204 
