BRIEFER ARTICLES 
ROOT DEVELOPMENT OF WHEAT SEEDLINGS 
(WITH ONE FIGURE) 
In a study of the salt requirements of wheat in water cultures, 
certain conditions under which wheat seedlings developed relatively 
large root systems were noted. Wheat seedlings with shoots 8-10 cm. 
high and roots 10-12 cm. long were set out according to the usual 
method employed for solution culture experiments, in two quart Mason 
jars filled with tap water from the laboratory. The cultures were 
allowed to grow for six weeks at a temperature range of 22-32°C. 
and without renewal of the tap water. At the end of this period the 
tops of the cultures had grown about 12-16 cm. high (having gained 
from 2 to 4cm.) and the root mass measured 70-80 cm. in length. 
In some cultures, however, single roots had attained a length of over 
roocm. So far as the total dry weight of these cultures was concerned, 
it may be stated that about one-half was contained in the roots. 
It was at first thought that the relatively low total salt concentra- 
tion of the tap water was responsible for the results. The tap water 
of the laboratory contained a total salt concentration whose osmotic 
value was calculated to be approximately equal to o.1 atmosphere 
pressure. To test this supposition as being the cause for the extraor- 
dinary long root growth of the wheat seedlings, several different kinds 
of complete nutrient solutions were prepared, each having a total salt 
concentration giving an osmotic value equal to about o.1 atmosphere 
pressure, and these were used as the culture media for wheat. These 
dilute solutions, which contained all of the chemical constituents essen- 
tial for plant growth, proved to be relatively poor media for the root 
development of wheat aera nother set of tests, however, with 
solutions of th Its and sa Pro] those of these dilute solu- 
tions but of greater total ( here), proved to be very 
good media for the root penis of wheat seedlings. These results 
suggested that it might be the absence or the deficiency of an element 
in the tap water that was responsible for the results. Tests were then 
made using nutrient solutions of a total salt concentration equal to give 
about o.5 atmosphere osmotic pressure, but modified so as to omit one 
Botanical Gazette, vol. 2] [404 
