74 BOTANICAL GAZETTE [SEPTEMBER 
(table VI) made just as much growth in length in a period of six 
weeks in Pfeffer’s solution plus 2 per cent glucose as in Pfeffer’s 
solution plus 2 per cent glucose and 400 ppm of autolized yeast. 
TABLE VI 
GROWTH OF EXCISED CORN ROOTS IN STERILE NUTRIENT rasa ti IN DARK; IN ONE 
CASE ap a yimoema ISED ROOT TIPS NOT TRANSFERRED; IN OTHER TIPS CUT OFF 
AND T SFERRED TO FRESH cantina SOLUTIONS AT iach OF TWO WEEKS, 
powtiiopes FROM DATA IN TABLE 
Average sessing on 
1 Average |Dry weight 
Addition to Prerrer’s solution | Transfers | No. roots se fe Tength no. seco} ~ ale per 10 
(cm.) (cm.) ary roots {roots (gm.) 
February 5—March 19 
inva d a emaed woes nee None 9 2.0 20.4 84 0.0898 
a min autolized yeast...}........ 13 1.93 20.57 | 97 0.0635 
February 5~March 19 
UR Ed ee eet GNCES wiles 3 9Q-10 t.7 15.8 719.5 oO.1 
pon apni autolized yeast...|........ 22.0 94.8 | 0.0971 
TABLE VII 
EFFECTS OF ie ae AND 80 PPM OF AUTOLIZED YEAST EXTRACT ON GROWTH OF EXCISED 
RN ROOT TIPS IN STERILE NUTRIENT SOLUTIONS IN D 
ay / Average origi-| Average gain| Average no. | Dry weight 
Addition to Prerrer’s solu- 
. No. roots nal length in ‘ieweth secondary | per ro roots 
tion+2% glucose (em.) ‘cmn,) nate (gm.) 
r. April 3-April 17 
NONE i ei ea es 10 +57 pS | 65 0.1054 
NONE. ea 10 os 11.i2 Oe pices es eee 
ONE Ss ce eas ey to +75 11.25 OS fie cee wenee 
NODE. sot se kay at .. 1.68 12.22 71 0.0826 
2. April r7—April 30 
ae cacy rane Near 8 soe a. 25 7:5 9.0027 
IO DOM Yeast... cis: 5 1.96 3.48 9.9 0.0047 
40 ppb yeast; 2... z 1.9 2.5 O08 olives ees 
86 ppm Yeast: i oa 3 2.0 2.8 Ce ee eee 
3. April 30~May 14 
a Ville Obes eee 8 1.4 2 ° gah kes 
50 Pom YeRst. . 5.2 ee. 5 1.8 ss oe ie ee eeg or 
40 ppm yeast. 2.2.55). 2 1.8 13 Corr dees ke 
So ppm yeast oo... 2 1.6 ae a le so aes 
