Nov. 15, 1924 
A Bacterial Leaf spot of Martynia 
487 
Uschinsky’s solution. —Clouding is 
moderate, sometimes heavy with a ring 
or pellicle and after about a week the 
medium is light green. After about 
8 weeks the cultures are a creamy 
yellow in color and have pellicles 2 to 
4 mm. thick. These pellicles extend in 
viscid threads or swirls down into the 
liquid when shaken, but do not sink. 
There is a small amount of viscid pre¬ 
cipitate. 
Fermi’s solution. — Clouding is 
light. A heavy pellicle forms in a few 
days and the medium takes on a green¬ 
ish tinge. After 2 or 3 weeks the pel¬ 
licle may be 5 mm. deep. After about 
8 weeks the cultures are a deep cream 
color and the pellicle hangs in long vis¬ 
cid strings or loops from the surface. 
There is no precipitate. 
Agar colonies. —Growth in 2 days 
is moderate, circular, smooth, glisten¬ 
ing, raised, 1 to 2 mm. in diameter, with 
margins entire. By transmitted light 
fish scale markings become evident in 
young colonies but later disappear (PL 
2, A). After 4 to 5 days colonies be¬ 
come umbonate (PL 3, C, D). In about 
a week they are 6 to 10 mm. in diam¬ 
eter in thin sown plates and the medium 
becomes greenish in tint. Older colo¬ 
nies become translucent. 
Gelatin colonies. —Growth is mod¬ 
erate, circular, crateriform, the margin 
is somewhat filamentous, liquefaction 
is saucer-shaped, internal structure is 
granular filamentous. Liquefaction is 
evident in 1 to 2 days and is completed 
in about a week, depending upon the 
numbers of colonies on a plate. 
Blood serum. —There is good growth 
in 48 hours, smooth, glistening, filiform, 
cream colored, butyrous. In 5 days 
the blood serum begins to clear under 
the cultures and becomes slightly de¬ 
pressed. After 2 to 3 weeks the serum 
is brown and transparent. The slant 
is thin and depressed under the growth. 
physiology 
Temperature relations. —The op¬ 
timum temperature for growth is about 
25° C., the maximum about 37°, the 
minimum about 1.5°. The thermal 
death point is 49°. 
Optimum reaction and toleration 
limits.— The optimum reaction is be¬ 
tween + 15 and +20 or P H 6.0 to 6.8. 
There was growth at + 26, P H 5.4, but 
no growth at +30, P H 5.2. There was 
a trace of growth at —8, P H 8.9, and 
no growth at —11, P H 9.2. 
Toleration of acids. —Isolation No. 
I grew in 0.1 per cent and 0.2 per cent 
of tartaric, malic, and citric acids, all 
cultures turning yellowish to bright 
green. The acids were added to neu¬ 
tral broth giving the following reac¬ 
tions : 
Tartaric, 0.1, +10, P H 7.2; 0.2, +23, 
P H 6.0. 
Malic, 0.1, +12, P H 7.0; 0.2, +25, 
P H 5.8. 
Citric, 0.1, +13, P H 7.0; 0.2, +26, 
P H 5.9. 
These acids were also added to un¬ 
corrected broth +20, P H 6.1, to give 
definite P H reactions, and cultures grew 
in the following reactions but not above 
them: 
Tartaric, +29, P H 5.2. 
Malic, +28, P H 5.4; +33, P H 5.2. 
Citric, +28, P H 5.7; +33, P H 5.4. 
Chromogenesis. —Nutrient broth, 
agar, and gelatin are slightly greened. 
Steamed potato cylinders become cream 
colored to tan. 
Indol production. —Cultures were 
grown in a solution of 1 per cent pep¬ 
tone, 0.5 per cent disodium phosphate, 
and 0.1 per cent magnesium sulphate 
for 17 days. Tested with H 2 S0 4 and 
sodium nitrite, results were negative. 
The same test was made in broth 
cultures grown for 4 days. Broth 
cultures 2 weeks old were tested by 
the Ehrlich and Salkowski methods 
recommended in the “ Manual ot 
Methods.” There was no indication of 
indol production. 
H 2 S production. —Strips of lead 
acetate paper were suspended over 
broth, agar, potato and rutabaga cyl¬ 
inders. There was no discoloration of 
the paper. 
Stabs were made 3 in media contain¬ 
ing 5 c. c. of beer extract peptone agar 
and 5 c. c. of 0.1 per cent basic acetate. 
Growth at the surface gradually 
turned light brown, later medium 
3 Following the method recommended by the 1923 “Manual of Methods." 
EXPLANATORY LEGEND FOR PLATE 2 
Cross sections of infected leaves of Martynia louisiana (= MTproboscidea). Cut 5 m thick. Carbol fuchsin 
stain. Photographed Mar., 1924. 
A—Beginning infection. Substomatal cavity filled with bacteria. X 1900. 
B—Beginning infection with bacteria in intercellular spaces. X 1900. 
C .—Advancing margin of a 13-day old lesion. Infected tissue has collapsed. Bacteria are most abundant 
near the margin of the lesion and also appear outside the leaf tissue. X 180. 
