ae BOTANICAL GAZETTE [SEPTEMBER 
root is attached to the grain. Peptone and autolized yeast, how- 
ever, were found to be distinctly beneficial. These two substances 
were selected because they contained a variety of comparatively 
simple organic nitrogenous materials, and because they are known 
to be beneficial to the growth of lower plants, such as the bacteria or 
the yeasts. 
TABLE II 
EFFECT OF PEPTONE AND AUTOLIZED YEAST ON GROWTH IN DARK OF CORN ROOT TIPS 
CUT OFF AND TRANSFERRED 
dition t Average | Average | Average |Dry weight 
P¥EFFER’S solution | No. roots — si th no. side perro |Original P, ta 
+2% glucose (cm.) ng’ roots [roots (gm.) ¥ 
zr. June 21—July 4 
Bone eis ales I 11.6 68 0.0487 4.5 6.8 
INGORE. oes, 8 1.7 2.7 68 60 4.5 6.5 
None..........: 8 1.9 12.8 63 0.0485 4.5 6.3 
Nene. isi 8 1.6 Pe 8 0.0030 AGS 5.04 
0.0 tO; enh 8 47 4.3 16.0 | 0.0283 6.5 6.5 
0.02% yeast..... bay 2.2 19.90 | 0.0371 5.2 8.3 
3. July 22—August 20 
None. 054 3c: 8 rs ©.05 Cool ewes as 4.6 
°. o4ch pectone 4 1.8 A 18 H.8 6.42 
0.02% yeast..... 2 r6 5.2 21.0 | i ceeie ee 5.45 
4. August 20-November 12 
None 8 eee ee a ae ee re ee 
oO. 04% pete: 3 2.0 1.6 ASS Pee i a OAS 
0.02% yeast..... I 2.0 2.5 AiO ere oh ee or cae oe 
The first experiment with peptone and autolized yeast was begun 
June 21, 1920, and completed November 12 of the same year. The 
second experiment extended from December 13, 1920, to February 
5, 1921. Both experiments demonstrated that excised corn roots 
whose tips were severed and transferred about every two weeks 
would grow in the dark in sterile solutions containing peptone or 
autolized yeast, glucose, and the salts of Pfeffer’s solution for four 
to six two-week periods, while without the peptone or autolized 
