Mar. 3,1933 
Gray Mold of Castor Bean 
695 
Experiment IV. March 18. In an attempt to influence apothecium production 
m pure culture, strains 3, 5, 7, 9, 12, 13, and 14 were transferred to new tubes, and the 
originals, all containing an abundance of sclerotia were submitted to the following 
conditions: 
No. 3 was placed at once in a moist chamber at room temperature. 
No. 5 in ice box for 48 hours at io° to 13 0 C., then as in No. 3. 
No. 7 above a freezing mixture starting at -io° C., overnight, in a well insulated 
fireless cooker, then as in No. 3. 
No. 9 above a freezing mixture overnight, then as in No. 3. 
No. 12 in ice box for 14 hours, than as in No. 3. 
No. 12 2d in freezing mixture overnight, then as in No. 3. ‘ 
No. 13 in freezing mixture, with gradual rise to + io° C., 36 hours in all, then as 
in No. 3. 
No. 14 in freezing mixture overnight, then as in No. 3. 
The moist chamber was on a shelf in the laboratory, some distance from any window. 
The cultures were watched for several weeks. No development of apothecia occurred 
on any of them under those conditions. Finally they were removed from the moist 
chamber and placed in a culture-tube rack on the laboratory shelf. 
Eventually, later in the summer, several sclerotia from these tubes 
gave rise to apothecial stalks. Included in those so doing were tubes 
Nos. 9 and 13, which showed that the actual freezing of the sclerotia 
was in no way injurious to the life of the fungus. Neither did it stimu¬ 
late apothecium production in any way. 
Experiment V.—April 12. A large number of field sclerotia were placed in 
Petri dishes of unsterilized moist sand. These were subjected to varying conditions, 
particularly with regard to temperature. Plate No. 6 placed in a moist chamber 
at room temperature was the first (May 10) to start to develop apothecia. No. 4 was 
held until May 24 in a moist chamber in a warm dark room without development 
of apothecia and on this date was moved out of doors, still maintaining moist chamber 
conditions. Almost immediately thereafter apothecia began to develop. 
Nos. 2 and 5, held in the ice box until May 26, were on this date placed out of doors 
with No. 4; and also shortly afterward they developed apothecia. On May 26 plates 
3 and 6, the former having been held for the first week in the ice box, each had a 
dozen or so beautiful apothecia. 
From this experiment it would appear that high humidity and a warm 
temperature are the primary requisites for apothecium production. 
There are strong indications that light as well is an essential factor. 
Experiment VI.—April 15. Several large, black sclerotia from various pure culture 
tubes were picked out under sterile conditions and placed half buried in sterile sand 
in Petri dishes. These were subjected to varying temperature conditions as in ex¬ 
periment V. Here, too, the cooling in the ice box and alternate cooling and warming 
had no beneficial effect, for apothecia were first produced on the plate placed promptly 
under a bell jar under room temperature conditions. On May 10 sclerotia from strain 
B 11 showed two large apothecial stalks developing. On May 26, in addition to ma¬ 
ture apothecia from B 11 they were found also from strains B 1, B 19, B 21, and B 21C. 
In this case mature apothecia were produced from definite single coni- 
dium strains of the organism, namely B 11, and B 19, under sterile con¬ 
ditions. 
Experiment VII.—April 17. A large number of sclerotia from castor-bean inflo¬ 
rescences and stalks in the field were placed in sterile sand in Petri dishes and sub¬ 
jected to varying temperature. As in experiments V and VI there was no particular 
difference in apothecium production in the different lots. On May 10, plate 1, placed 
at once under warm, moist conditions, showed many stalks arising. Plate 2, placed 
first in the ice box for a week and then placed with No. 1, also showed several. Plate 3, 
in a covered Petri dish, showed two or three on May 17. Evidently the lack of aeration 
had inhibited their development to some extent. On May 26, Nos. 1 and 2 showed 
dozens of mature apothecia, which were used to swell the collection. No. 3 as well 
showed several mature apothecia. 
At the same time that these sclerotia were started, others were surface sterilized by 
momentary immersion in 95 per cent alcohol, and then for 3 minutes in 1 to 1,000 
mercuric chlorid followed by two changes of sterile water, then placed on a corn-meal 
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