[Vor. 8 
30 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
NITROGEN METABOLISM WITH SPECIAL REFERENCE TO CUL- 
TURAL AND ENZYME STUDIES 
Attention was next turned to the problem of the requirements 
of the strains for nitrogen. Research has long shown that diff- 
erent fungi and bacteria behave in the most diverse manner in 
respect to a source of nitrogen, and it seemed that an experimen- 
tal study of the various strains of Rhizoctonia might throw some 
light on physiological differentiation. 
TABLE XIX 
THE Ir oig OF THE STRAINS ON VARIOUS NITROGENOUS CULTURE 
DIA. THE GROWTH "— E REPRESENT DRY WEIGHT 
IN GRA 
Solution 
containing Pa P1 | P4 P7 B1 H B3 
Amygdalin 6.8 .012 | .015 | .027 | .007 | .012 | .005 
Sclerotia 1 1 0 0 1 1 
Asparagin 6.0 .135 .030 .070 .010 .165 .010 
Sclerotia 3 3 0 0 3 1 
Caffeine 6.8 0 0 0 0 0 0 
Sclerotia 0 0 0 0 0 0 
Casein 6.0 . 155 . 120 . 090 . 520 . 165 .110 
Sclerotia 3 2 0 1 3 2 
Legumin 6.2 110 055 . 100 025 125 020 
Sclerotia 1 2 1 1 ] 
Peptone 6.8 "Em .120 .120 .020 .160 . 010 
Sclerotia 2 2 0 1 2 1 
Cultural experiment.—For this experiment .5 per cent solu- 
tions of amygdalin, asparagin, caffeine, casein, legumin, and 
bacto-peptone were prepared, each in a medium containing 2 
per cent maltose, .025 per cent magnesium sulphate, and .025 
per cent monobasic potassium phosphate. Flasks were arranged 
with 25-cc. quantities and after inoculation were incubated for 
16 days. 
Concerning the requirements of nitrogen for each strain, there 
is some specialization exhibited. As a rule the growth of Pl 
and H in all the media is more abundant than that of the remain- 
ing strains, with the exception of B1 on the casein medium. 
