60 BOTANICAL GAZETTE [SEPTEMBER 
Growth of roots attached and detached from grain 
That the seed supplies material different either in kind or in 
quantity from that present in the culture solution is evidenced by 
the following experiment, in which a comparison was made of the 
growth of roots attached to the grain and detached from the grain. 
In this experiment corn grains were sterilized by W1Lson’s method 
as before, and germinated on sterile agar in Petri dishes. After 
germination, and when the roots were about 3 cm. long, some of the 
grains were placed in socc. of sterile modified Pfeffer’s solution 
plus 2 per cent glucose in 125 cc. Erlenmeyer flasks, and some of the 
root tips were cut off and transferred to the same kind of solution 
and culture flasks. All were placed in the dark at room temperature. 
At the end of twelve days the roots attached to the grains had 
gained 26.6 cm., had produced 102 secondary roots on the average, 
and weighed per ten roots 0.5120gm. Those detached from the 
grain had gained 12.4 cm., had eighty-three secondary roots, and 
weighed per ten roots but 0.1138 gm. (table [). 
TABLE I 
GROWTH IN DARK OF ROOTS ATTACHED TO GRAIN AND DETACHED FROM GRAIN, IN 
PFEFFER’S SOLUTION PLUS 2 PER CENT GLUCOSE 
be Average.ori Average no. | D 
Condition nal er co ae dav: secondary | per ro roots 
(cm.) (cm.) roots (gm.) 
Attached tO gral ee 2.9 26.6 102 0.5120 
emai ee oe See ae we £7 12.4 83 0.1138 
In tubes of 1 per cent agar a similar difference in the growth of 
roots attached to the grain and detached from the grain was noted. 
In fig. 1 the growth of an excised root tip at the end of two weeks in 
modified Pfeffer’s solution plus 2 per cent glucose containing 1 per 
cent agar, and the growth in the same period of time of a root which 
was left attached to the grain are shown. Comparing the latter root 
with the excised root, its greater length, greater size of secondary 
roots, and greater diameter of root tip are clearly evident. 
The effect of peptone and autolized yeast 
If we assume that the stoppage in growth of an excised corn root 
tip on continued transfers is because glucose, the mineral salts of 
