206 
PACIFIC SCIENCE, VoL VIII, April, 1954 
TABLE 1 
A List of Media Used in the Cultivation of 
Phycopeltis, Showing the Number of Days 
Necessary for New Filaments to Appear 
MEDIUM 
DAYS 
Basic 
8 
Basic and sucrose 
16 
Basic and juice from leaf upon which the epi- 
phyte grew 
12 
Basic, juice from leaf upon which the epiphyte 
grew, and sucrose 
* 
Basic, juice from leaf upon which the epiphyte 
grew, and fragmented discs 
16 
Basic, sucrose, and fragmented discs 
22 
* Discs did not produce new filaments even after 80 days of 
incubation. 
agar produced the most rapid growth, this 
medium was used to cultivate the algal mate- 
rial needed for further experimentation. 
EXPERIMENTAL PROCEDURE 
The addition of growth-affecting substances 
to the basic media brought about differences 
in rate of growth and in the predominant 
color of the algae, although each medium was 
adjusted to a pH of 5.6 and placed under 
similar environmental conditions. It was ob- 
served that, when a mass of Phycopeltis fila- 
ments is grown on nutrient media, new 
filaments are sent out horizontally from the 
center of the mass, forming a nearly circular 
disc. This being the case, the growth rate of 
an algal mass could be determined by measur- 
ing the change in area covered by the disc, 
a method previously used by the writer (1952) . 
The diameters of the masses were measured 
at the time of inoculation and again on the 
thirty-second day after inoculation. The dif- 
ference, in millimeters, was then recorded. 
Four cultures in each class were used in the 
experiment, and the average increase was 
computed. Table 2 shows the color and the 
amount of growth after 32 days of incubation 
under continuous light produced by fluores- 
cent daylight bulbs and natural daylight. 
Temperature under which the cultures grew 
varied from 25°C. in natural daylight to 33°C. 
in light produced by fluorescent daylight 
bulbs. Experimental results showed, however, 
that this temperature variation had no effect 
upon color change. 
When growth substances were added to the 
basic medium, the algal discs grown thereon 
for 32 days showed a greater increase in area 
covered than did those grown for the same 
length of time on the control medium. Al- 
though all algal masses were predominantly 
green (Eig. 1) at the time of inoculation, a 
distinct change in color was observed in the 
algal filaments grown on most of the media 
containing growth substances. After the 32- 
day growth period, the hematochrome pig- 
ment was predominant in those algae grown 
upon media containing indole acetic acid and 
colchicine in both continuous light produced 
by fluorescent daylight biilbs and in natural 
daylight (Fig. 2). Algae grown upon the me- 
dium containing benzimidazole became 
orange in color when grown under continu- 
ous light produced by fluorescent daylight 
bulbs but remained green under natural day- 
light. Benzimidazole had no effect upon the 
TABLE 2 
Results After Algae Had Grown on Media 
FOR 32 Days. Green Phycopeltis Masses 
Were Used as Inocula 
MEDIUM 
FLUORESCENT 
(daylight) * 
NATURAL 
DAYLIGHT t 
Color 
Diameter 
increase 
Color 
Diameter 
increase 
Basic (controls) . 
Green 
Mm. 
0.05 
Green 
Mm. 
0.03 
Basic plus indole 
acetic acid 1 
gamma/ml. . . . 
Orange 
0.12 
Orange 
0.09 
Basic plus col- 
chicine 0.1 per 
cent 
Orange 
0.15 
Orange 
0.12 
Basic plus ben- 
zimidazole 2.5 
X 10-3m 
Orange 
0.09 
Green 
0.05 
* Continuous for 24 hours each day. 
t No light supplied during the night. 
