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An investigation to determine the effect of varying the quality of fluorescent light on the growth of the blue-green alga, Gloeothece rupestris (Lyngb.) Born

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An Investigation to Determine the Effect
of Varying the Quality of Fluorescent
Light on the Growth of the Blue-Green Alga,
Gloeothece minestris (Lyngb.) Born.
A Thesis
Presented to
the Faculty of the Department of Botany
University of Southern California
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
Earl De Gowin
June 1940
UMI Number: EP41407
All rights reserved
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■ In the unlikely event that the author did not send a complete manuscript
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a note will indicate the deletion.
Dissertation PybfeH.ng
UMI EP41407
Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author.
Microform Edition © ProQuest LLC.
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unauthorized copying under Title 17, United States Code
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T h i s thesis, w r i t t e n by
........... EmLDE_ag\iin............
u n d e r the d i r e c t i o n o f h i . s.. F a c u l t y C o m m i t t e e ,
a n d a p p r o v e d by a l l it s m e m b e r s , has been
pr esen ted to a n d accepted by the C o u n c i l on
G r a d u a t e S t u d y a nd Re search in p a r t i a l f u l f i l l ­
m e n t o f the re q u ire m e n ts f o r the degree o f
MASTER OF SCIENCE
D ean
Secretary
D a te
JUKE
19^0 .
F a c u lty Com m ittee
I
vi
ACKNOWLEDGMENTS
The author wishes to express his sincere gratitude
to Dr. G. R. Johnstone, under whose direction this work
was carried out; whose encouragement, and sympathetic
guidance during the course of the research work and
preparation of this paper, are deeply appreciated.
Grateful acknowledgment is also extended to Dr. H.
de Forest, and Dr. C. Lindegren, members of the Thesis
Committee, for their helpful and constructive criticisms
in the revision of the manuscript; and to Dr* R. E. Vollrath, of the Department of Physics, for his essential
technical advice, as well as recommendation of the
calorimeter for use in measuring the radiant energy
transmitted through the Wratten light filters*
vii
TABLE OP CONTENTS
CHAPTER
I.
PAGE
INTRODUCTION ....................................
Historical summary
II.
..........................
1
2
Significance of the s t u d y ...................
4
GENERAL CHARACTERISTICS OF BLUE-GREEN ALGAE ...
5
Theories as to o r i g i n ..............
5
Pigments .....................................
6
Composition of the cell wall and
gelatinous sheath
..............
...........
Method of reproduction
7
8
Contamination of reservoirs, lakes, and
aquariums
.................................
Diversity of habitats
III.
IV.
.....................
9
10
REVIEW OF RELATED INVESTIGATIONS ...............
12
EXPERIMENTAL P R O C E D U R E .........................
21
Description of the plant
...................
Description of the apparatus •••••........
Calorimeter
21
22
...... •.......................
22
Cultufe filter b o x .........................
25
Fluorescent Mazda lamp
27
The light chamber
.................
.......
Photoelectric photometer
51
................
51
viii
CHAPTER IV. (Continued)
PAGE
Wratten light filters
.....................
54
Method of Preparation of the
Nutrient Solution
......................
58
Inoculation of the nutrient solution
by Gloeothece •...........
59
Method of approximately uniform
distribution of algal cells in the
250 cc. Erlenmeyer cultufe flasks ••••••
59
Light intensity equalization of the
Wratten light filters ..................
40
Determination of the radiant energy
transmitted through the Wratten
light filters • •........................ •
42
Method of determining the cell
population in each culture
......
42
Method of determining turbidity of the
V.
algal growth in the nutrient solution •••
44
RESULTS AND D I S C U S S I O N .........................
46
Cell-count technique
....................
46
Turbidity of the algal g r o w t h ............
50
Microscopic examination of algal cells •••••
50
General appearance of algal cells ••••••••••
55
ix
CHAPTER
VI*
PAGE
SUMMARY
OPPROCEDURE AND R E S U L T S .................
Procedure
.......
R e s u l t s ........
•.........
••••••
61
61
64
SUPPLEMENT . ............................................
66
LITERATURE CITED ........................................
95
X I
LIST OF TABLES
TABLES IN THE TEXT:
I.
II.
Wratten light filters
••
55
Composition of Detmerfs nutrient
solution
III.
PAGE
.....
57
Distances from the fluorescent lamps
at which the light intensity of the
Wratten filters was equal to 5.0
microamperes
IV.
.................
41
Quantity of radiant energy transmitted
by Wratten filters at predetermined
distances above the fluorescent lamps
V.
......
45
Comparison of the growth in the 13
cultures of Gloeothece rapestrls In
relation to the increase and
decrease of cell populations .............
VI.
48
The effect of various light rays on
the populations of Gloeothece, as
determined by the haemacytometer
cell-count t e c h n i q u e .......
VII.
49
Turbidity of algal cultures representing
changes in the cell and colony
populations, resulting from the
influences of several light filters
.........
51
xi
TABLE
VIII.
PAGE
An extension of Table VII and the
rearrangement of filter numbers to
show effect of various light rays
on the algal cell and colony
populations .................................. •»
IX.
52
The effect of various light rays on
the morphological and physiological
structures of the blue-green alga
cells, as determined by microscopic
examination
X.
.....
54
55
The effect of various light rays on
Gloeothece« as determined by
general appearance
............
57
58
TABLES IN THE SUPPLEMENT:
XI.
Data on determinations of light
intensity of Wratten Filter No. 29.
Oranges-reds (680-700A°) ......................
XII.
67
Data on determinations of light
intensity of Wratten Filter No. 49.
Blues-Blue-greens (550-510^)
XIII.
.....
68
Data on determinations of light
intensity of Wratten Filter No. 61.
Greens (485-610A0 ) ..................
69
xii
TABLE
XIV*
PAGE
Data on determinations of light
intensity of Wratten Filter No* 70*
Deep red (680-700A0 ) ..........................
XV*
70
Data on determinations of light
intensity of Wratten Filter No* 71*
Orange-red (580-700A°) ........................
XVI.
71
Data on determinations of light
intensity of Wratten Filter No* 72*
Orange-yellow (680-700A°)
XVII*
...............
72
Data on determinations of light
intensity of Wratten Filter No* 73*
Yellow-green (680-700A°, 550-625A0 ) ........
XVIII.
73
Data on determinations of light
Intensity of Wratten Filter No* 74*
Pure green (510-575A0 ) ........................
XIX*
74
Data on determinations of light
intensity of Wratten Filter No. 75*
Blue-green (475-540A0 , 690-700A°) ............
XX*
75
Data on determinations of light
intensity of Wratten Filter No* 76*
Violet (682-700A°i 330-480A0 ) ................
XXI*
Data on determinations of light
Intensity of Wratten Filter No.
88*
Infra red (680-700A°) .........................
XXII*
76
77
Data on determinations of light
Intensity of light control ..................
78
xiii
TABLE
XXIII*
PAGE
Cell population in culture exposed
to radiant energy through Wratten
Filter No*
XXIV*
29* Oranges-reds
................
79
Cell population in culture exposed
to radiant energy through Wratten
Filter No*
XXV*
49* Blues-blue-greens *.............
80
Cell population in culture exposed
to radiant energy through Wratten
Filter No*
XXVI*
61* Greens
.....................
81
Cell population in culture exposed
to radiant energy through Wratten
Filter No* 70*
XXVII*
Deep r e d ................... ••••
82
Cell population in culture exposed
to radiant energy through Wratten
Filter No*
XXVIII*
71* Orange-red
...................
83
Cell population in culture exposed
to radiant energy through Wratten
Filter No*
XXIX.
72* Orange-yellow
................
84
Cell population in culture exposed
to radiant energy through Wratten
Filter No.
XXX.
73* Yellow-green ..................
85
Cell population In culture exposed
to radiant energy through Wratten
Filter No.
74* Pure g r e e n ...................
86
xiv
TABLE
XXXI.
PAGE
Cell population in culture exposed
to radiant energy through Wratten
Filter No.
XXXII.
75. Blue-green
.............
87
76. Violet ........................
88
Cell population in culture exposed
to radiant energy through Wratten
Filter No.
XXXIII.
Cell population in culture exposed
to radiant energy through Wratten
Filter No.
XXXIV.
8 8 . Infra
red
Cell population in culture exposed
to full visible spectrum
XXXV.
......
..............
Cell population in culture exposed to
darkness •••••••......................
89
XV
LIST OP FIGURES
FIGURES IN THE TEXT:
1#
PAGE
Photomicrograph or Gloeothece rupestrls,
showing the various stages of fission
and the gelatinous sheath • ................... •
2.
23
Design of calorimeter, showing
construction and arrangement In
light-proof box ••«.......
3#
4*
24
Design of culture filter box... • •...............
26
Photograph showing the seven fluorescent
lamps and the arrangement of the culture
filter boxes at the various levels••••••.••«•
5*
29
The comparison of a daylight fluorescent
lamp spectrum, with the spectrum of
natural daylight • •.... .......................
6
*
7#
Design of the light chamber • •••
••
30
32
Spectral sensitivity of photronic cell
(No. 594), with various window
materials.
Taken from Technical Data
on Weston Photpelectrie Cells
8
#
.....
33
A concise presentation of the visible
spectrum, showing the spectral
regions absorbed and transmitted
by the Wratten light filters
................
36
xv i
FIGURES IN THE1 TEXT:
9.
PAGE
Photographs showing the quantities of
growth in the
12
culture flasks, and
the arrangement used to determine the
growth by general appearance
10*
................
59
Photograph showing the comparative
quantities of algal growth in the light
and dark controls
................
50
FIGURES IN THE SUPPLEMENT:
11*
Wave-length absorption and transmission
of Filters
12*
29,
49,
61,
and
70 ......
92
7 4 ......
93
...........
94
Wave-length absorption and transmission
of Filters
13*
Nos.
Nos.
71,
72,
73,
and
Wave-length absorption and transmission
of Filters
Nos.
75,
76,
and
8 8
CHAPTER I
INTRODUCTION
The biological effects of radiation have been
extensively explored, according to Duggar (1936), who,
with his collaborators, assembled much of the available
material on irradiation of organisms.
Special studies
of the effects of radiation on unicellular green algae
include the work of Klebs (1896), and Brooker (1925), in
relation to reproduction; Radais (1900), on growth in
light and darkness; Grintzesco (1903), Negelein (1922),
Harder (1923), and Iggena (1938), on responses to light
intensities; Nadison (1910), on responses to different
light qualities; Dangeard (1927) and Meier (1932-36) on
various light intensities and wave-lengths; and Emerson
and Lewis (1939) on factors influencing photosynthesis.
Among these several investigators, Iggena (1938)
appears as the only one who has worked on the responses
of blue-green algae to light.
Since most of the investi­
gations cited have been confined to the green algae, it is
evident that the blue-green algae offer a relatively unex­
plored field.
Therefore, the study of varying the quality
of fluorescent light on the growth of the blue-green alga,
Gloeothece rupestris (Lyngb* Born., appears to offer a new
phase of investigation in the field of biological radiation.
Historical summary♦
This is an endeavor to present
in a concise manner the work and results obtained by the
investigators cited in the introduction, with the exception
of Brooker (1925), Meier (1952-36), Iggena (1938), and
Emerson (1938), whose investigations will be discussed in
Chapter III.
For the earlier work on radiation,- that of the 18th
century and the first half of the 19th century, one may con­
sult the monograph by Spoehr (1925) on photosynthesis.
In
most of these early investigations, not sufficient attention
was devoted to the distribution of energy in the various
spectral regions studied.
Klebs (1896) made extensive investigations to deter­
mine the conditions of reproduction in several algae and
fungi, which demonstrated the effect of light and darkness
on gamete formation in Chlamydomonas media and showed that
only vegetative division takes place in darkness.
A two per
cent sugar solution aided growth but did not entirely replace
the influence of light.
Radais (1900) became interested in the responses of
unicellular plants to light and, suspecting it as an indirect
factor in nutrition, he grew Chlorella vulgaris on steamed
potato slices and malt extract in light and darkness* result­
ing in a similar multiplication of the alga in each instance.
This suggested that nutrition, rather than light, is the
fundamental factor which influences reproduction*
5
Grintzesco (1903)investigated the responses of Chlorella,
when exposed to various light intensities, and found that too
much light (direct sunlight) is unfavorable and injures the
cell membrane#
While studying the photosynthetic activity of the uni­
cellular alga, Chlorella, Warburg and Negelein (1922) observed
great variation in the efficiency of these plants#
They found
that when plants are raised under conditions of high light in­
tensity the plants convert but a small fraction of the absorbed
radiant energy into chemical energy, while plants grown under
low light intensity convert a larger portion of the absorbed
energy into chemical energy#
Harder (1923), in his studies to determine the effect
of different light intensities on Fhormidlum foveolarum, dis­
covered that these plants can utilize only low intensities for
their photosynthetic process#
Nadison (1910) grew Stiehococcus Kbacillaris under bell
jars of colored solutions transmitting various ranges of known
wave-lengths of light, and found that yellow light caused the
cells to acquire abnormal shapes, while cultures grown in blue
light attained a stage of development similar to those grown in
white light, which were normal in color and form#
The effect of ultra-violet rays on unicellular green
algae, was determined by Dangeard (1912), who immersed a piece
of white blotting paper in a culture flask containing Chlorella
vulgaris and radiated it in a quartz spectograph#
The algae
4
grew best in the region of from 6700 to
6 6 OOA0 ,
while no trace
of the algae was visible in the region of from 5200 to 4000A°.
This brief review of the literature, indicates the in­
tensive studies that have been devoted to the green algae and
the apparent neglect of the blue-green algae*
Significance of the study*
following reasons:
It is significant for the
(1 ) the biological effects of radiation on
blue-green algae in a relatively unexplored field; (2 ) the
study includes the use of a practical and simple calorimeter
for the measurement of transmitted radiant energy; (3) Wratten
light filters are used to isolate portions of the spectrum;
and (4) the application of daylight fluorescent lamps is made
a source of photochemical energy*
A detailed account of the
significance of these topics will begin to appear in Chapter
IV.
CHAPTER II
GENERAL CHARACTERISTICS OF BLUE-GREEN ALGAE
The characteristics of blue-green algae as here presented,
appear to have an important bearing on the elucidation of the
problem*
These features include:
(1) conjectures as to origin
(2 ) various pigments; (5) composition of cell wall and gelantinous sheath; (4) method of reproduction; (5) contamination
of reservoirs, lakes and aquariums; and (6 ) the diversity of
habitats*
Theories as to origin*
Gardner (1906) believed that
the blue-green algae were representatives of a very ancient
group which had adapted itself to the most diverse habitats
while retaining its original simplicity of structure*
According to Chamberlain (1916), when conditions of
temperature and environment were almost constant on the earth
the first form of life appeared in the waters*
This was
simply a mass of protoplasm floating in the sea as a planktonic organism*
Chamberlain believes that members of marine
and fresh-water plankton were evolved from these organisms*
Agreeing somewhat with Chamberlain's conjecture, Smith
(1933) states that each of the brown, green, and red algae
originated from a series of primitive motile unicellular forms.
The complete absence of flagellated vegetative and reproductive
6
cells in the Myxophyceae suggests very strongly that motile
cells have never been present in the blue-green series*
Fritsch (1935) maintains that the blue-green algae stand
on a relatively low plane of differentiation which has remained
practically unaltered through long epochs of the earth1s history*
It is certain that it had an independent origin, though what it
may have been is not known because of the fact that few fossils
of Myxophyeeae exist, and some of these are not beyond a doubt*
Incorporating the hypothesis of Chamberlain as to the
earth’s origin, Tilden (1935) contends that the blue-green algae
are what appear to have been the most ancient and primitive of
all plants, and they, according to her theory, possessed chloro­
phyll and accessory pigments which provided for the utilization of
sunlight in the manufacture of their own food.
Tiffany (1938) believes that life must have originated
after the atmosphere became what it is today, and that this
first life consisted, possibly, of simply constructed organisms
containing chlorophyll*
This first form of life was single­
celled, motile, and capable of prolonged dormancy.
It is his
belief that such a plant may have originated all of the various
kinds of algae that are known to the world today*
Pigments*
The chromatophore of the protoplasts in the
blue-green algae is not, according to Smith (1933), a chromato­
phore In the sense that this term is used in connection with
other algae*
In some cases the pigments appear to be uniformly
diffused through the chrcanoplastic portion of the protoplast,
7
and, in others, the coloring matter appears to lie in minute
granules scattered throughout the peripheral portion of the
protoplasm*
Chlorophyll, a green pigment, is among those that
are included in the chromoplasm*
However, it is more or less
hidden, or masked by phycocyanin in a blue pigment, the two
pigments together giving the blue-green color to the blue-green
algae.
The third pigment, according to Tilden, is carotin,
orange in color and occurring in granular form.
The fourth
pigment, Rhycoerythrin, is red and predominates over other pig­
ments in some forms, so that there are blue-green algae which
are red.
One such form, Trichodesium erythraeum, is a floating
marine plant which gives a bright red to the water wherever it
appears in large quantities.
The Red Sea owes its name to the
seasonal coloring of its waters by this organism.
The causes for the development of the various pigments in
different proportions are not definitely known.
According to
Smith (1933), the theory of complementary chromatic adaptation
was first applied to the Myxophyceae to explain experiments with
Oscillatoria sancta. which gave evidence that individuals, culti­
vated in a light of different colors, assumed the colors to
which they were exposed.
Composition of the cell wall and gelatinous sheath*
The
wall surrounding protoplasts of unicellular Myxophyceae, is com­
posed of two concentric portions: an inner, thin, firm layer
immediately outside of the plasma membrane, and an outer gelantinous portion (the sheath) that is often of considerable
8
thickness.
For a number of years, according to Smith (1933),
it was believed that the portion of the wall immediately ex­
ternal to the protoplast was composed largely of chitin, but
microchemical studies of Bfyxophyceae during the past decade are
practically unanimous in denying the presence of chitin*
In
regard to the matter Smith (1933) has stated that most of the
recent workers hold that cellulose is the chief chemical com­
pound but it has also been suggested that this layer may be
composed of a pectin-like hemicellulose/
The sheath surrounding individual cells is often dis­
tinctly stratified.
This is probably due to a hydrolysis to
different degrees of various portions in the gelatinous layer.
In some cases, such as in Phromidium, the sheaths surrounding
individual cells are completely fused with one another and show
no Indication of lamination.
The presence of a sheath around
a cell undoubtedly increases the water-absorbing capacity of
the plant, and Is one of the main reasons why Myxophyceae are
so successful in terrestial habitats.
Method of reproduction.
In all species of Cfaroococoaleg«
the only regular method of reproduction is that of cell division
or fission, Smith (1933) asserts, and is the only one employed
by the most primitive plants#
Organisms which are reproduced
by this method in a sense never die, except as the result of
food shortage or other unfavorable conditions.
Senescence and
natural death, as most animals and plants experience them, do
not take place among these forms.
When a single individual
9
plant has grown to maturity it divides into two daughter cells
of equal size.
Ordinarily, these two cells remain united
within a common gelatinous envelope and the indefinite repeti­
tion of division may result in a colony containing many cells.
Colony reproduction is a matter of chance and depends upon the
accidental breaking of the colonial envelope.
If the envelope
is soft and tends to dissolve, as in Gloeocapsa» the colony
never grows to a large size before becoming separated into two
or more daughter colonies*
Contamination of reservoirs» lakes, and aquarium s .
Blue-
green algae are commonly found in water containing decaying
organic matter because, in addition to the food which these algae
manufacture, they require certain organic substances to be found
in such waters.
When the algae die they undergo decomposition;
certain species secrete a toxin In the water, thus rendering the
water poisonous to livestock and other animals*
During the late summer there is a pronounced amount of
blue-green algae in some lakes, particularly the ones rich in
organic matter, and to such an extent that the water becomes
discolored*
This condition is commonly known as ,!water bloom.w
According to Fair and Whipple (1927), the unpleasant odors
which accompany wwater bloom” are produced when the vegetative
matter In the water starts to decay.
This represents the
first stage of decomposition and, as It progresses, the odors
become disagreeable and later are offensive*
Blue-green algae are frequently observed to grow in great
10
abundance in aquariums, especially if the water is stagnant
and contains decaying organic material*
Their presence in
aquariums is injurious for two reasons: (1 ) during their decay
the oxygen content of the water is decreased; and (2 ) the par­
tially decomposed material may clog the gills of fish to such
an extent that they die*
This unpleasant condition creates
a problem for those who are interested in maintaining clean and
wbalancedM aquariums*
It has been suggested that a covering
of yellow cellophane would eliminate such contamination, and
preliminary experiments appear to support this view*
However,
if the contamination is due to over-feeding, it would seem that
control of this factor should give better results than the
yellow cellophane coverings*
Diversity of habitats*
Myxophyceae are found in all
parts of the world*
They maintain themselves in rushing toron
rents, cataracts,/boulders of streams, and they play a very
conspicuous part as pioneers in preparing the way for other
forms of like nature*
Representatives of the Myxophyceae
are always present In plankton catches from fresh water lakes
and ponds*
These catches usually consist of one or more species
of Chroococcus, Coelosphaerium, Microcystis; or Anabaena*
The
proportion of the Myxophyceae, with respect to other algae, is
dependent on the time of year and chemical condition of the
water*
Usually, blue-green algae occur In abundance only i#-
during the warm months of the year although certain species,
such as Qsclllatoria prolifica, may develop In quantity
during the winter.
Blue-green algae constitute an important part of the
algal flora of many subaerial habitats#
They are usually in­
conspicuous but, in certain parts of the world, especially
regions with a pronounced rainy season, the soil algae, ac­
cording to Moore and Carter (1923), may develop to such an
extent that they form patches of several square yards in ex­
tent#
Although the M y x o p h y c e a e are generally restricted to
the upper 18 inches of the soil, Moore and Carter relate
finding them as deep as 8 feet below the surface#
Myxophyceae often grow in springs in the western part
of the United States.
The best known, and most thoroughly
investigated, are those found in Yellowstone National Park#
Here, the algae have been discovered in water having a tempera­
ture of 75°C. to 77°C.
Tilden states that species which have become acclimated
to hot springs are not found elsewhere.
Her theory as to
their origin is that these plants must have been universally
distributed in the first warm waters of the young earth#
CHAPTER III
REVIEW OP RELATED IHVESTIGATIONS
This chapter presents the studies of Brooker (1925),
Meier (1932-36), Iggena (1938), and Emerson (1939), whose
very thorough investigations to determine the biological
effects of radiation on unicellular plants have elucidated
most of the problems that the older investigators struggled
with, reaching only partial success.
The experimental
methods employed in each of their investigations are similar
to the ones used in this problem, hence are considered of
utmost importance#
To determine the effect of light of different wave­
lengths on the rate of reproduction of Volvox aureus and
Closterium acerosum, Brooker (1925) was confronted with the
perplexing problem of determining whether photosynthesis de­
pended on wave-length or was, within the units of the visible
spectrum, a matter of total light intensity.
To solve the
question, he grew the chlorophyll-containing organisms in
light of the same intensity but of different wave-lengths,
and took their rate of reproduction as a criterion for the
efficiency of the wave-lengths utilized in photosynthesis#
This method, Brooker realized, may be regarded as indirect,
as other things besides photosynthesis are involved in the
reproduction rate, but he supports his theory by stating that,
fundamentally, the rate of reproduction in chlorophyllous
15
organisms is obviously dependent on their ability to manu­
facture food*
The experimental procedure involved the use of three
boxes, each having the front open and a light-tight door
behind*
Over the front of each box a color filter was
fixed, chosen so that the spectrum was divided into three
portions with little overlapping*
58, and 47 were selected.
Wratten filters, Nos. 26,
The red filter, No. 26, had a
total transmission of 22 per cent; the green filter, No. 58,
had a total transmission of 25 per cent, and the blue filter,
No. 47, had a total transmission of 2*9 per cent*
All fil­
ters were brought to very nearly the same total transmission
by placing a prepared film filter of approximately 12*5 per
cent behind the red and green filters in the "color boxes*M
The neutral film filters were prepared in the follow­
ing manner:
pieces of photographic film were exposed to a weak
light for various brief periods, then developed, fixed, and
matched visually against a set of neutral filters of known
percentage transmission*
Two of the prepared filters were
selected which came, as nearly as could be judged, midway
between the 10 per cent and the 15 per cent of known trans­
mission*
The three boxes, with the filters in position, were
set up, side by side, in an east window where they received
2 hours of sunlight on sunny days*
Five individuals, or
colonies, were placed in filtered water from the habitat of
14
the organisms, in each of three vials, and a vial was placed
in each of the "boxes#
The number of organisms present in
each vial was recorded at intervals of several days#
Brooker states, as result of this investigation, that
the wave-lengths of light play a very important part in the
metabolism of the organisms, and that, if the reproduction
rate is a criterion of photosynthetic activity, then the
photosynthesis depends on wave-length,- red light being highly
efficient, blue much less so, and green inefficient#
Meier (1932) was interested in determining the lethal
action of ultra-violet rays on a unicellular green alga#
She
therefore construeted a quartz spectograph for the purpose of
exposing algae to a monochromatic light under sterile condi­
tions, thereby to observe the effectiveness of a wide range
of wave-lengths in a definite time#
In the experimental
procedure, suspensions of cells were inoculated on sterile
agar in petri dishes#
One set of cultures was placed under
bell jars and grown in diffused light in the northern window
of the Smithsonian tower#
The other petri dishes were covered
with sterile cellophane and then placed In the spectograph#
After an exposure of 21 minutes to the spectrum the cover of a
sterile petri dish was placed over the cellophane and the cul­
ture returned to the bell jar from which It had been taken*
No change was obtained in the growth of the algae until one
week after the exposure#
Then, white lines, resulting from
complete decolonization of the chlorophyll and death of the
green cells, corresponded to the typical mercury lines for
all wave-lengths shorter than 3,000A°.
Meier employed another method in the same year, that of
taking the cells as they were growing in the agar, and placing
them in a closed sterile brass container with a quartz window.
This was done by arranging a decker in front of the slit of
the spectograph to permit the exposure of different portions
of the plate for various periods of time.
The cultures of the
green alga were subjected to five irradiative periods of from 6
and 20 minutes, and 1, 3, and 18 hours.
Within two days after
the first exposure, the results of all five exposures were ap­
parent.
Meier therefore proved, as a result of his investiga­
tion, that unicellular green algae showed lethal sensitivity at
about 2,600A°.
The wave-length, 3,130A°, slightly longer than
the short wave-length limit of solar radiation reaching the
earth*s surface, had no lethal effect on the algal cells, al ­
though they were of a much higher intensity than the toxic wave
lengths.
She calculated that the lethal rays, in killing the
algal cells for radiotoxic quantum, were wave-lengths ranging
from 2,250 to 3,022A°.
The reason that ultra-violet rays in natural conditions
are not injurious to plants may be due to the fact that through
out the agesliving organisms have probably become adapted to
solar radiation as it is received on the earth*s surface.
is therefore not surprising that radiation of wave-lengths
It
16
shorter than the solar limit produces unusual effects*
Large
amounts of ultra-violet of certain wave-length ranges may not
he lethal hut, on the contrary, stimulating to the growth of
unicellular plants*
Meier (1934) inoculated a 3-liter flask of Detmer1s
nutrient solution, diltited 1:3, with Stichococcus bacillaris to
determine the effect of various wave-lengths of light on the
green alga*
A metal tahle was constructed, which contained
four glass-bottomed water-baths, each capable of holding six
Erlenmeyer flasks of 300 cc* capacity*
Each flask was en­
closed in a container with a light filter on the bottom, each
being one of a duplicate series of 12 short wave-length cut-off
filters; that is, a set which transmitted progressively shorter
and shorter wave-lengths,- from one transmitting deep red, to
those which transmitted the whole spectrum*
Pour water-baths
were connected to a centrally located thermostated mixing cham­
ber which kept the cells agitated in the flask*
The cultures
were illuminated from below by artificial light from 300-watt
Masada daylight lamps placed 20 centimeters under each of the
water-baths*
A summary of the results shows that chlorophyll was formed
under all the filters but were in the best condition when the
wave-lengths of the blue-violet region were included*
A multi­
plication of algae, ranging from twofold to fourfold, was ob­
tained in the cultures*
17
Meier found, by computing growth ratios for many narrow
ranges of wave-lengths and estimating approximate values under
the energy curves of the effective wave-lengths, that a wide
red and infra red complex of waves (6500-7800A°) was moderately
effective for the multiplication of the algal cells.
Cultures,
growing in light where the wave-lengths were cut off at 3700,
4000, 4500, 4600, 4800, and 5000A°A, were in especially good
condition.
Most of the disintegration of the chloroplasts
occurred where the light was cut off at 5200, 5600, 5800, and 5900
5900A°.
This investigation was in progress from February 7 to
March 24, 1933.
Meier (1934) placed under 3 water-baths a 300-watt Mazda
lamp, 20 centimeters from the glass bottoms of the baths, to
determine the effects of different intensities on the green
algae, Stichococcus bacillaris and Chiore11a vulgaris.
Under a
fourth water-bath the lamp was placed 40 centimeters from the
bottom.
In bath 1 the cultures were stationary, while the cul­
tures in the other three flasks were continuously agitated so
that the cells were more evenly dispersed in the culture media.
Cultures in baths 1, 3, and 4, were lighted continuously
throughout the experiment, but those In bath 2 were Illuminated
for only 6 hours daily.
In the results obtained, the best
growth occurred in cultures grown in intermittent light at a
distance 20 centimeters from the light.
She also proved that
agitation favors multiplication, as the cells do not collect
in large masses.
This investigation was in progress from June
19 to July 17, 1934.
18
Meier (1936) remodeled the metal table she used in her
previous investigations, in order to investigate the growth of
the green alga, Stlohococcus» in isolated wave-length regions#
This table was constructed with four new, glass-bottomed waterbaths, each holding two 500 cc. Erlenmeyer flasks#
The four
water-baths were connected to the centrally located thermostated
mixing chamber which kept the temperature at 19°C.
In order
to ensure uniform dispersion of the algal cells, a common driv­
ing mechanism continually agitated the Erlenmeyer flasks#
One
of the cultures in each bath was illuminated from below by mono­
chromatic light from a light filter furnished with Mazda projec­
tion lamps#
The other culture in each bath was contained in an
Erlenmeyer flask which had been painted black to prevent the en­
trance of any light, thus providing a check on the cultures in
each bath#
Christiansen filters were used for the green (5000-
5600A°) and yellow (5500-6200A°) regions; a combined Christiansen
filter, and a Corning heat-resisting red glass filter, provided
the red (6000-7500A°); a saturated copper sulfate solution gave
the blue (4000-5200A°); and a Corning heat-transmitting glass
filter, No# 254, gave the infra red (8500-12000A ° )•
The results
showed a multiplication of more than fourfold algal cells in the
daylight cultures, supported by nephelometric measurements; over
threefold in the blue, and over twofold in the yellow and red
regions#
The green region proved to be destructive as there was
a decrease in the number of cells#
The infra red region made
little change in cell multiplication, the cultures being very
similar to those grown in darkness#
Cells with beautiful green
19
plastids were found in the cultures grown in the blue, red, and
yellow regions, as well as in the daylight.
The cells exposed
to the green region had little green plastids but contained much
granular material; those exposed to the infra red had large vacu­
oles and granular contents, but contained green plastids.
Color­
less cells, and cells with faded, yellow-green plastids and dis­
integrated contents, were characteristic of the cultures exposed
to darkness.
This investigation was in progress from April 9 to
April 23, 1936.
Iggena (1938), while investigating the effects of various
factors, such as different periods of light exposures, high and
low light intensities, intermittent and continuous light expos­
ures, and nutrition on the growth of the blue-green algae, made
the following discoveries:
(1) that 17 hours of illumination per
day gave better growth than 9 or 12 hours; (2) that with a con­
stant amount of light, growth was better at low intensities and
long durations than with high intensities and short durations;
(3) that intermittent light, with one-minute light and dark inter­
vals, was the least effective for the growth of pure cultures of
blue-green algae; and (4) that the presence of glucose in low
light intensities caused a somewhat greater increase in growth
than occurred in its absence*
Emerson and Lewis (1939) grew liquid cultures of Chlorella
in 300 cc. Erlenmeyer flasks to determine the quantum efficiency
of photosynthesis in unicellular green algae.
During growth,
the culture flasks stood in shallow, glass dishes accommodating
20
Tour flasks each, surrounded by a stream of running water*
Tungsten filament lamps, internally frosted, were located
below the glass dishes and provided 24 hours of illumination
each day*
For most of the work, however, 100-watt lamps were
used without reflectors.
The Intensity of illumination was
varied by changing the distance of the lamps rather than watt
ratings*
The cultures were aerated with a slow stream of 5
per cent carbon dioxide in the air*
The cells were stirred
by gently shaking the flasks twice a day*
In their results,
Emerson and Lewis showed that the culturing of Chlorella pyrenoidosa at high Intensities is unfavorable for development of
high photosynthetic efficiency, although growth is much faster
by this process*
Growing cultures of Chlorella in blue and yellow mercury
lines, and In various regions of the neon spectrum, Emerson and
Lewis obtained quantum yield on the wave-length of light In
which the cells were grown*
As to results gained, they stated
that they believed it to be possible, with proper attention to
other factors, for the control of the wave-length to lead to
further improvement in the quantum yield*
CHAPTER IV
EXPERIMENTAL PROCEDURE
This chapter is divided into three main parts: (1) it
describes the blue-green alga, Gloeothece rupestris; (2) the
apparatus employed, viz*, a calorimeter, culture filter box,
fluorescent lamps, light chamber, photoelectric photometer,
and Wratten light filters; and (3) the experimental procedure
used, including the preparation of the nutrient solution and
the inoculation of the nutrient medium with the blue-green
algal cells; the method of uniform distribution of the algal
cells in the 13 Erlenmeyer flasks of 250 cc* capacity each;
equalization of the light intensity of the radiant energy
transmitted by Wratten light filters; counting of the bluegreen algal cells with the haemacytometer; and estimation of
algal populations in the cultures by measurements of their
densities*
Description of the plant*
The unicellular blue-green
alga, Gloeothece rupestris. is an elongated cell that varies
from 4 to 5.5
in length.
Each of the cylindrical cells of
Gloeothece rupestris has rounded poles surrounded by a dis­
tinct envelope that is somewhat confluent with those of ad­
joining cells in the colony*
The adhesion between the cellu­
lar envelopes is so insecure that cells are constantly break­
ing away from the colony and, as a result, the colonies rarely
22
contain more than
a
Tew cells*
These have homogeneous proto­
plasts of various colors which always divide at right angles to
their long axes (Figure 1}*
Description of the apparatus *
Calorimeter*
In order to
determine the amount of radiant energy transmitted by the Wrat­
ten light filters at a known distance from the fluorescent
lamps (Table III), the use of a calorimeter was suggested and
recommended by Dr* Richard E* Vollrath*
This apparatus was
constructed by the Glass Blowing Laboratory of Los Angeles,
and consists chiefly of two glass bulbs, each 3*5 inches in
diameter, flattened in "pan-cake" fashion to a height of 0.6
m m * , painted thoroughly on the outside with lampblack to absorb
all incidental rays of radiation, and connected together by a
scaled capillary tube of 1*16 Inch bore (Figure 2).
To make
certain that the capillary tube was free of dirt particles,
5 cc. of 95 per cent alcohol were poured through an opening in
each of the absorption bulbs and allowed to travel back and
forth through the capillary tube*
This procedure was repeated
three or four times, then all the excess alcohol was drained
from the apparatus*
Following this, a drop of 95 per cent al­
cohol, colored with aceto-carmine, was placed with the aid of
an eye-dropper into one of the open chambers and allowed to
travel until it was in the center of the capillary tube*
Three drops of ether were then placed in both chambers and
sealing wax quickly applied to the openings*
If the volumes
FIGURE 1.
Photomicrograph of Gloeothece rupestris
showing the various stages of fission
and the gelantinous sheath.
sheath;
(A) the
(B) elongated parent cell about
to divide;
(C) fission nearly complete;
and (D) the two daughter cells completely
segregated*
23
FIGURE 1
FIGURE 2.
Plan of calorimeter, showing construction
and arrangement in light-proof box.
Q ) ABSOAt TXHf C€lL JT
@ ABSOJtPT/OA
©
P iAN
W£ W
c e u 'B"
SCALED CAP1LLAAY TUBS
CALOR/METER
r*r
zm .
dorr 0/1
view
Figure 2
E N D V IE W
CO
of ether vapor in both cells are equal in size and pressure,
the colored alcohol should remain motionless in the one posi­
tion#
When one bulb is exposed to heat or light, the ether
vapor expands in the one being exposed and moves the colored
indicator in the capillary tube, this movement being in pro­
portion to the radiant energy (heat) absorbed#
To complete the construction of this calorimeter so as
to measure the radiant energy transmitted through the selected
Wratten light filters, which will be described later, a box
was built containing two compartments, separated by opaque
baffles to ensure uniform temperatures of both bulbs except
for whatever change results from the exposure of one bulb#
One of the bulbs was placed in the light-proof compartment,
while the other was placed directly opposite a l#5-inch-diameter
opening in the other chamber#
On the outside of this opening
wooden slots were so arranged that a Wratten light filter could
easily be placed and removed from over the face of the exposed
bulb chamber#
Thus, with a filter in proper position, the
only light admitted into the box must first be transmitted by
the Wratten filter#
Culture filter box#
In this investigation, 13 similar
culture boxes were constructed, one for each of the 11 Wratten
filters, and two for the controls#
One of these controls was
exposed to fluorescent light transmitted through transparent
glass similar to that used in the construction of the Wratten
filters, while the other was maintained in total darkness#
FIGURE 3.
Plan of culture filter box.
CULTURE
FILTER BOX
//"
(jo)JPcs s'xfx^piYWoob
wood /m o b
T
® 2 PCS. l { x g x p PLYWOOD
(£ )s "x s "x f PLYWOOD
(6)2 Pcs.£xfrfsW//f AtoLE
_L
( s ) 2 t ’* i * £
t-t,
o■*-#£»
(£}2/>cs. z , i \ £ x £ ' s o f t wood
5ftDi
Q)zPcs. S ”X8*X+*Tiyw ooD
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- - L -'L
B O TTO M
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Figure 3
SC4LE r =/
CO
Oi
Precaution was taken during construction of the boxes to make
them light-proof, the only source of light permitted to enter
coming through an opening in the bottom 1.5 inches in
diameter (Figure 3).
Inside, directly over the opening, was
placed the 250 cc. Erlenmeyer flask containing the culture of
Gloeothece in the nutrient medium, while on the outside three
wooden slots similar to those on the calorimeter were arranged
so as to hold the Wratten filter directly over the face of the
opening.
Here again, any outside source of light must first
be transmitted through the filter before reaching the culture
in the bottom of the flask.
green algal cells
This method of exposing blue-
to various light wave-lengths is advantageous
for five reasons: (1) since each box is light-proof, with only
one opening, the light intensity of each filter can easily be
measured with the photoelectric photometer and microarameter;
(2) by removing the filter from the bottom of the box the tur­
bidity of the culture in the nutrient medium can easily be de­
termined with the photoelectric photometer; (3) the boxes can
be adjusted over the light source in any position desired; (4)
the area of light distribution received by each flask is equal;
and (5) the culture flasks are kept free of dirt and contamin­
ation.
Fluorescent Mazda Lamp.
The source of light used In
radiation investigations Is of paramount importance.
While it
seems desirable to adhere to natural conditions of illumination
by using sunlight for experimental work in spite of the high
28
intensity this source of light, according to Spoehr (1926),
is not very satisfactory because, at the surface of the earth,
sunlight varies in intensity and composition from hour to hour
and from day to day*
The high intensity of the infra red rays
in sunlight introduces experimental difficulties*
Artificial
sources of light, therefore, have many advantages because (1)
the intensity can be kept highly constant and (2) the infra
red radiation can be largely eliminated by choosing the proper
source of light*
The 7 Mazda daylight fluorescent lamps (Figure 4) used,
were each 24 inches in length, 1-1/2 inches in diameter, and
had a capacity of 20 watts*
These lamps consisted of a tubu­
lar bulb coated on the inside with a fluorescent material, and
filled with argon gas and mercury vapor*
electrodes, one at each end*
The lamps have two
The electrodes are connected to
a suitable source of voltage which results in an electrical
discharge through the gas contained in the tubes*
This dis­
charge produces netra-violet light which excites the fluorescent
material to emit visible radiation*
The most significant feature of fluorescent lamps is the
precise and efficient manner in which light, approximating day­
light quality, can be produced with a minimum loss in energy
as heat (Figure 5)*
The objective of the daylight lamp is to
duplicate the whiteness of natural daylight, which means dis­
tributing the energy throughout the colors of the spectrum,
thus approximating the spectrum of daylight*
FIGURE 4*
Photograph showing the seven fluorescent
lamps and the arrangement of the culture
filter boxes at the various levels*
29
F IG U R E
4
FIGURE 5*
The comparison of a daylight fluorescent
lamp spectrum, with the spectrum of
natural daylight.
Photographed from
Engineering Data on Fluorescent Lamps.
p. 14*
30
DAYLIGHT FLUORESCENT M A Z D A LAMP
CLEAR DAY IN JUNE
RELATIVE ENERGY
-I------------j
oc.
O
>*
o
uu
o
o
o
o
o
o
o
o
8
CM
o
o
o
o
z
<
cc
o
X
o
o
o
LT>
CD
ANGSTROMS
FIGURE 5
o
o
o
o
o
oo
o
A method of comparing td%
daylight fluorescent lamp with
natural daylight is to divide
the spectrum into bands of
minimum perceptible color
differences.
A t the left,
each band contains 16 ju s t
perceptible color differences
except the two in the red end
which have 8 each. In most
bands the differences are
small; the green and yellow
lines do not unbalance the
color. The red deficiency of
the fluorescent lamp is in the
deep red where the luminosity
o f the eye is low.
31
The 11ght chamber#
One of the two methods used to
determine the amount of growth in each culture flask was by
recording the density of the algal cells growing in the
nutrient solution#
To obtain this reading the filters were
removed from the bottom of all culture filter boxes and each
box was consecutively placed in its proper position in the
light chamber (Figure 6)#
The exact procedure used in this
method of determining growth is presented in the latter part
of this paper#
Photoelectric photometer#
This apparatus employs as
its light sensitive element a Weston photoelectric cell
(No. 594), which was chosen because its maximum sensitivity
occurs fairly close to the maximum visible light intensity
and the electrical current generated is sufficient without
amplification#
The electrical current generated by the
conversion into electrical energy of the radiant energy upon
the sensitive element of the photoelectric cell is read on a
microammeter, and by reference to a calibration graph is de­
termined for the particular Weston cell in use the readings
in microamperes are Recorded as light intensity in foot
candles#
Further specific information regarding the con­
struction and operation of this apparatus may be acquired
by consulting the publication, Technical Data on Weston
Photoelectric Cells.
For detailed information regarding the
spectral intensity of the photronic cell (No. 594), see
Figure 7#
FIGURE 6.
Plan of light chamber*
32
11 CUT CHAMBER FOR D E T E R WNING GROWTH OF CULTURES
TN ERLENMBYSR F L A S K S
23
FIGURE 6.
4
FIGURE 7
Spectral sensitivity of photronic cell (No, 594)
with various window materials.
Taken from
Technical Data on Weston Photoelectric Cells,
IIIoI'lJII
R E L A T IV E S E N S I T I V I T Y
■LIUm I II llTTgH
w
34
This photoelectric photometer was devised by Lester H#
Cushman, and a paper describing it was published#"1*
Later on,
Erwin H# Miller, Jr., tested the instrument and published a
paper on its use and standardization#
Wratten light filters#
p
Since the purpose of this in­
vestigation has been to determine the effect of varying the
quality of light furnished by fluorescent lamps on the growth
of the blue-green alga, Grloeothece rupestris. 11 Wratten light
filters were deemed necessary#
Three of the filters, Nos* 29,
49, and 61 were chosen because they divided the visible spec­
trum into three^spectral portions#
No# 29 transmitted all
the oranges and reds of the spectrum, No# 49 transmitted all
the blues and blue-greens, and No# 61 transmitted all the
greens of the spectrum#
The remaining filters (Table 1),
divided the three main portions, or the entire visible spec­
trum including the infra red, into smaller units#
They are
known as ^monochromatic filters * since they transmitted light
rays of only one color (Figure 8)#
According to the Eastman Kodak Company, Wratten light
filters have been recognized since 1909 as occupying a unique
position for photographic, technical, and scientific work#
A Lester H. Cushman,11A Light Intensity Meter for Field
Use,n School Science and Mathematics, December 1933. Pp# 969976.
2 Erwin H. Miller, Jr., 11The Use of a Light Intensity
Meter a11 School Science and Mathematics, January 1936, Pp# 34-38#
35
TABLE I
WRATTER LIGHT FILTERS
Manufacturers1
numbers
Color portion
of the spectrum
Wave-lengths in
Angstrom Units
29
Oranges-Reds
680-700
49
Blue s-Blue-Gre ens
350-510
61
Greens
485-610
70
Deep Red
650-700
71
Orange-Red
600-700
72
Orange-Yellow
580-700
73
Yellow-Green
550-625
680-700
74
Pure Green
510-575
75
Blue-Green
475-540
690-700
76
Violet
330-480
682-700
88
Infra Red
680-700
36
FIGURE 8*
A concise presentation of the visible
spectrum, showing the spectral regions
absorbed and transmitted by Wratten
filters.
36
onn
700
,
■
600
000
400
CC
88
73
29 T ,
7Pt
74
49
WRA n m a s BXlJ ;r$
j&rWAve,-! aagt
FI GTJRE 8
N o. 6101, T Jni\ c r s i t y B o o k s to re , L o s A n g e le s
;ted*
76
37
TABLE II
COMPOSITION OP DETMER1S NUTRIENT SOLUTION*
Chemicals
Grams
Calcium nitrate
1.0
Potassium chloride
0.25
Magnesium sulphate
0.25
Potassium acid phosphate
0.25
Iron
0.002
Distilled water
1 liter
"^This solution, mad© up In the above
proportions, was diluted one to two*
Taken from Meier (1934)* P. 5.
The wide rang© of* filters available, their exact adjustment
to the designed purpose, as well as the care given to their
preparation, have brought about this well-deserved reputation.
The process of manufacturing Wratten light filters is
patented by the Eastman Kodak Company, hence the formulae are
unknown to the public.
They are prepared from organic dyes,
made by mixing a given weight of dye with a certain amount of
gelatin.
The mixture is then poured upon prepared glass plates
and, after drying, the film is stripped from the glass.
Each
filter is standardized by comparison with a permanent standard
in a special instrument which applies an optical form of limit
gauge to its color.
Method of Preparation of the nutrient solution.
In order
to have a uniform medium for all cultures of Gloeothece rupestris, Detmer1s nutrient solution, which is a modified Koch
solution, was employed (Table II).
This solution was not
sterilized in the autoclave because, as determined by prev­
ious investigations, this process appears to destroy the nu­
trient value and drive off the oxygen.
Blue-green algal cells
Gloeothece» when inoculated in a sterilized Detmer solution,
turned a grayish-white after a period of 3 weeks, while algal
cells grown in an unsterilized Detmer solution maintained
their natural bluish-green color after the same period of
time.
Cultures grown in plain tap water maintained their
natural color but their growth is not so rapid as when in a
nutrient solution.
Inoculation of the nutrient solution by Gloeothece.
The original culture consisted of 500 cc. of suspended bluegreen algal cells taken from a large glass container in which
this particular blue-green alga had been growing for 15 years.
The suspension of cells was allowed to filter slowly through
4 layers of cheesecloth, several times.
After microscopic
examination, the procedure was seen to have eliminated much
residue
and also a filamentous alga, Plectonema. which had
contaminated the original culture.
The filtered suspension
of Gloeothece cells was then poured into a 3 liter pyrex
glass flask containing the nutrient medium.
Method of approximately uniform distribution of algal
cells in the 250 cc. Erlenmeyer culture flasks.
Each Erlen-
meyer flask was first placed in a solution for cleaning glass­
ware.
It was then thoroughly rinsed several times with dis­
tilled water and filled with 150 cc. of the distilled water.
The water level was then marked with a red wax pencil and the
water discarded.
The 3 liter pyrex glass flask, containing
the blue-green algal cells, was well shaken, thus bringing the
cells into a state of suspension and uniform distribution In
the nutrient solution.
Prom this large flask, each of the
13 culture flasks were quickly filled to the previous volume
marked at the 150 cc. level, and sealed with a sterilized
cotton plug.
40
Light intensity equalization of the Wratten light
fliters.
To obtain this data, each of the 11 Wratten fil­
ters was placed directly over the face of the photoelectric
cell and, with the aid of a yardstick, the filters were
exposed at consecutive 1-lnch intervals above the fluores­
cent lamps.
Since the photoelectric cell varies in its
relative spectral sensitivity to various wave-lengths of
light, the sensitivity of each wave-length was determined
from Figure 7.
The light intensity thus transmitted by
each filter at the various levels above the fluorescent
lamps (See Tables XI to XX in the supplement), was inter­
preted from these two sources of data.
The lowest reading, 5.0 microamperes, obtained at a
point 1 inch above the light source, was considered the
standard light intensity for all 12 cultures.
The various
heights at which the light intensity was 5.0 microamperes
for each filter was recorded (Table III), and the culture
filter boxes were adjusted to these levels.
To recheck the
positions of the culture boxes for light Intensity the photo­
electric cell was placed in the culture box.
This technique
was repeated for each culture box at the various heights, and
the second reading corresponded to the Initial one.
This
proved the equalization of light intensities above each filter
in the culture filter boxes when adjusted for exposure of the
alga to the various qualities of fluorescent light.
41
TABLE III
DISTANCES FROM THE FLUORESCENT LAMPS AT WHICH THE
LIGHT INTENSITY OF THE WRATTEN FILTERS WAS EQUAL
TO 5 MICROAMPERES
Filter
number
Inches from
light source
Microamperes *
29.
17.
5.0
49*
7.
5.0
61.
12.
5.0
70.
3.
5.0
71.
3.
5.0
72.
1.
5.0
73.
1.
5.0
74.
2.
5.0
75.
4.
5.0
76.
8.
5.0
88.
1.
5.0
24.
5.0
Light Control
^Determined with the photoelectric photometer
and microammeter.
Determination of the radiant energy transmitted
through the Wratten light filters♦
After equalizing the
units of light intensity in each culture filter box, the
next information to be obtained was the quantity of radiant
energy transmitted by the individual filters#
This was
determined by removing the filters from the bottom of the
culture boxes and placing them, one at a time, in proper
position on the calorimeter#
The distance of the calor­
imeter from the light source was determined by placing it
alongside the bottom of the corresponding culture box from
which the filter was removed.
At the end of a 30-seconds
exposure the position of the colored indicator
in the
graduated capillary tube was recorded (Table IV)#
Method of determining the blue-green algal cell
population in each culture#
One of the two methods used to
obtain a quantitive determination of growth in the individ­
ual cultures was the algal cell count technique with the aid
of a haemacytometer#
Culture flasks were gently shaken,
thus bringing the cells into a state of equal distribution
in the nutrient solution and, with the aid of a specially
constructed pipette the cells, in a drop of 0#1 cc# volume,
were placed next to the cover-glass and drawn over the count­
ing area of the glass slide by capillary attraction#
The
algal cells of Gloeothece» being of microscopic size and
like human blood corpuscles, were not hindered by the minute
distance between the cover-glass and the glass-slide counting
43
TABLE IV
QUANTITY OF RADIANT ENERGY TRANSMITTED BY THE
WRATTEN FILTERS AT PREDETERMINED DISTANCES
ABOVE THE FLUORESCENT LAMPS
Filter
No*
Inches above
the lamps
Radiant energy
In mm.*
17.
0.7
49*
7.
0.3
61 •
12.
0.3
70.
3.
1.1
71.
3.
0.8
72.
1.
0.2
73.
1*
0.3
74.
2.
0.2
75.
4.
0.2
76.
8.
0.1
CO
CD
1.
0.2
24.
1.6
•
29.
Light control
d e t e r m i n e d with the calorimeter*
chamber*
Only the large squares, which are marked off into
16 smaller squares of 1/20 mm* dimension, were used for the
counting fields*
Five readings were taken from each cul­
ture and the average number of algal cells present was thus
determined (See Tables XXIII to XXXV, Inclusive, in the sup­
plement).
The total average number of cells present in each
culture was determined for the initial and final readings of
this investigation and, in this manner, the increase or de­
crease of algal cells was obtained (Table V ) #
Method of determining the turbidity of the algal
growth in the nutrient solution*
This method for determining
the quantity of algal growth In the nutrient solution Included
the following procedures: The culture filter boxes, containing
the cultures of blue-green alga, were removed from their posi­
tions over the fluorescent lamps and, with the Wratten filters
removed, were placed one at a time in the light
(Figure 6).
chamber
Meanwhile, the culture flask was gently shaken
to ensure a uniform distribution of the algal cells*
The
sterilized cotton plug was then removed, the face of the
photoelectric cell placed directly over the wide mouth of the
250 cc* Erlenmeyer flask, and the 150-watt Mazda bulb In the
bottom of the chamber was turned on for an exposure period of
30 seconds*
At the end of this period the deflection of the
needle on the microammeter was recorded (Table VII)*
These readings were taken once a week and the results
obtained were interpreted in relation to the quantity of
growth or cell population in each culture (Table VIII).
In
other words, the larger the growth the greater became the
absorption and reflection of the light which penetrated the
nutrient solution.
Therefore the amount of light reaching
the sensitive photoelectric cell was in proportion to the
thickness of the algal growth in the nutrient solution.
46
CHAPTER V
RESULTS OF DISCUSSION
The interpretation of the results obtained in this
investigation, to determine the effect of varying the quality
of fluorescent light on the growth of the blue-green alga,
Gloeothece rupestrls» was taken from 4 sources of data* (1)
the data obtained by the microscopic cell count; (2) the
increase or decrease of microamperes in determining the density
of the algal growth in the nutrient solution; (3) the micro­
scopic examination of the algal cells from each alga culture
in relation to the physiological and morphological changes
in the algal cells; and (4) by the general appearance of the
plants in the individual culture flasks*
Cell count*
Two microscopic examinations of each
culture were made during the process of this Investigation
to determine the Increase or decrease of the cell population
In the cultures exposed to the various light rays (See Tables
XXII to XXXV, inclusive, In the supplement*
According to the
results obtained, a greater increase of the cell population
•3L
occurred in cultures exposed to the deep red and greens
spectral regions, while a decrease of the cell population
2
Wratten Light Filters. Fifteenth edition, revised;
Rochester, N# 1V*: Eastman kodak Company, 1938* 105 pp*
occurred in the cultures exposed to the blues-blue-greens
rays.
The remaining cultures, which were exposed to the
orange-reds, orange-red, pure green and violet rays, were
somewhat similar in their increase of cell population with
exception of the cultures exposed to the oranges-reds and
orange-red rays (Table V).
The cell population in these
cultures was slightly greater in comparison with the cell
population of the other cultures in that particular group.
The remaining cultures, which were exposed to the yellowgreen and infra red rays, attained only a slight increase
of cells.
The two controls, consisting of a culture ex­
posed to the full visible spectrum of the fluorescent lamps
and a culture grown in total darkness, presented an inter­
esting contrast in growth (Figure 8).
The culture grown
in darkness presented a final cell count similar to the
culture exposed to the infra red rays (Table V), while the
culture grown in the full visible spectrum had a cell popula
tion similar to the cultures exposed to the orange-red and
pure green rays.
Although the growth in the light control
culture was not as abundant as the culture exposed to the
deep red rays, it clearly illustrated the significance of
light for photosynthetic activity when comparison was made
with the culture grown in darkness.
Table VI provides material for interpretation of the
data presented in Table V.
TABLE V
COMPARISON OP THE GROWTH IN THE 13 CULTURES OP
THE BLUE-GREEN ALGA, GLOEOTHECE. IN RELATION TO
THE INCREASE AND DECREASE OP CELL POPULATIONS *
Culture
number
Initial Reading
Increase
Decrease
X 106
X 106
4.56
0.
0.
3.60
29.
9.60
14.16
49 m
9.60
6.00
61m
6.72
12.00
5.28
0.
70.
12.72
20.60
7.88
0.
71.
7.44
11.04
3.60
0.
9.60
10.32
.72
0.
73.
6.72
8.16
1.44
0.
74.
7.44
11.04
3.60
0.
75.
9.60
12.00
2.40
0.
76.
7.44
9.60
2.16
0.
•
00
CO
X 106
-a
to
•
X ID6
Pinal Reading
6.72
7.44
.72
0.
Dark
Control.
10.32
11.04
.72
0.
Light
Control
12.72
16.32
3.60
0.
&
Determined by microscopic count with the aid of the
Haema cy t ome ter «
TABLE VI
(Interpretation of Table V)
THE EFFECT OF VARIOUS LIGHT RAYS ON THE ALGAL CELL
POPULATION OF GLOEOTHECE, AS DETERMINED B Y THE
HAEMACYTOMETER CELL-COUNT TECHNIQUE*
Spectral
color range
Order of
changes In the
cell population
from greatest
to least, Nos.
1 to 8.
70.
Deep Red
1.
61.
Greens
2.
29.
Oranges-Reds
3.
71.
Orange-Red
4.
74.
Pure-Green
4.
Full visible
4.
75.
Blue-Green
5.
76.
Violet
5.
75.
Yellow-Green
6.
-a
to
•
Filter
number
Orange-Yellow
7.
88.
Infra Red
7.
None
7.
Blue s-Blue-Greens
8. Decreased
Light
Control•
Dark
Control.
49.
50
Turbidity of the algal growth in the nutrient solution*
According to Table VII the greater cell population occurred
In the cultures exposed to the deep red and greens region of
the spectrum*
The cultures exposed to the oranges-reds,
orange-red, pure green, and blue-green rays, displayed
noticeable decreases in microamperes due to the growth of the
organism in the nutrient solution*
Cultures which indicated
slight growth, were those exposed to the yellow-green, orangeyellow, infra red, and violet, while Culture No. 49, exposed
to the blues-blue-greens^spectral regions, plainly indicated
a decrease of microamperes, this condition being interpreted
as due to the destruction of the algal cells*
Table VII presents, in brief form, the growth rates of
the various cultures as determined by the amount of light
intensity of the radiant energy transmitted by the blue-green
alga culture suspended in the nutrient solution*
Table VIII provides material for interpretation of the
data to be found in Table VII*
Microscopic examination of algal cells*
Samples of
the algal cells from each of the 15 cultures were carefully
examined under a 44X power of the microscope*
The purpose
of this procedure was to determine the effects of the various
light rays on the formation of the gelantinous sheath, colored
pigments, and occurrence of colonies or single cells*
Little
1 Wratten Light Filters* Fifteenth edition, revised*
Rochester, N. Y.’s Eastman Kodak Company, 1938* 105 Pp*
51
TABLE VII
TURBIDITY OP ALGAL CULTURES RESULTING PROM THE
INFLUENCES OF THE SEVERAL WRATTEN LIGHT FILTERS
Measurements in Microamperes
March 27
April 6
29.
13.0
11.1
11.0
10.9
2.1
49.
12.5
12.3
12.2
12.8
0.0
61.
13.2
12.8
11.0
10.8
2.4
70.
13.5
13.0
11.5
10.9
2.6
71.
12.9
12.0
11.3
11.0
1.9
13.2
12.8
12.7
12.6
.6
73.
13.0
12.5
12.1
12.1
.9
74.
13.3
12.8
12.0
11.5
1.8
75.
12.5
12.2
11.8
11.0
1.5
76.
13.1
12.5
12.1
11.9
1.2
13.0
12.5
12.4
12.4
.6
Light con
trol.
12.9
12.5
11.1
10.8
2.1
Dark con­
trol.
13.0
12.8
12.6
12.6
•4
i
I
March 20
t
«o
Decrease
in micr.
March 13
•
CO
00
Filter
number
Increase
in micr.
*3
1
1
52
TABLE VIII
AH EXTENSION OP TABLE VII AND REARRANGEMENT OP
FILTER NUMBERS TO SHOW EFFECT OF VARIOUS LIGHT
RAYS ON THE ALGAL CELL AND COLONY POPULATIONS*
Filter
number
Spectral
color range
Order of changes
in the cell
population from
greatest to least,
Nos. 1 to 11
70.
Deep Red
1.
61.
Greens
2.
29.
Light
control
Orange s -Reds
3.
Full
3.
71.
Orange-Red
4.
74.
Pure Green
5.
75.
Blue-Green
6.
76.
Violet
7.
73.
Yellow-Green
8.
72.
Orange-Yellow
9.
88.
Dark
control
Infra Red
49
Blu e s-31u e -Gr e en
10.
10.
11.
Microscopic counts included the number of algal
cells composing a colony, plus individual cells
found in a free state (Tables XXIII to XXXIV).
53
difference was apparent except in those cultures exposed to
the infra red, darkness, blues, and blue-greens*
The algal
cells of the infra red and dark control cultures lacked the
bluish-green color characteristic of the normal plants.
They
had, instead, a whitish-yellow appearance closely resembling
the chlorotic condition of higher plant forms when kept in the
dark for a time*
The cultures exposed to the blues, and blue-
green rays, contained algal cells which proved to be most inter­
esting*
Many of the cells appeared undeveloped and, in sever­
al instances, it seemed as though the cell had been ruptured
because of a complete lack of cell contents*
In a colony of three
or four cells it was found that two or more of them were nor­
mal while the remainder of the same colony was deformed*
The
gelatinous sheath was fully developed In every instance, even
where the plant body was deformed or completely lacking*
Table IX shows, in a brief form, these results*
General appearance of algal cells*
To compare accur­
ately the quantity of blue-green alga growth in the individual
culture flasks proved to be quite difficult owing to distor­
tion caused by the nutrient solution*
To overcome this ob­
stacle a device was employed which provided light from a
fluorescent lamp to illuminate the bottom of each culture
flask, thus presenting the quantity of growth in clear-cut
fashion (Figures 7 and 8).
54
TABLE IX
THE EFFECT OF VARIOUS LIGHT RAYS ON THE MORPHOLOGICAL
AND PHYSIOLOGICAL STRUCTURE OF THE BLUE-GREEN ALGA
CELLS, AS DETERMINED BY MICROSCOPIC EXAMINATION
Spectral color
range
Microscopic appearance
70
Deep Red
Normal and healthy
61
Greens-Yellow-Green
Normal and healthy
29
Oranges-Reds
Normal and healthy
Light
Control
Full
Normal and healthy
71
Orange-Red
Normal and healthy
74
Pure Green
Normal and healthy
75
Blue Green
N6rmal*
Cells closely
combined in colonies*
76
Violet
Cells lack much granule
material* Appear to b<
in dormant stage
73
Yellow-Green
Normal* Few cells in
colonies; mostly as
individual cells
72
Or ang e -Ye 11 ow
Normal* Few stages of
cell fission seen
Filter
number
TABLE IX (Continued)
THE EFFECT OF VARIOUS LIGHT RAYS ON THE MORPHOLOGICAL
AND PHYSIOLOGICAL STRUCTURE OF THE BLUE-GREEN ALGA
CELLS, AS DETERMINED B Y MICROSCOPIC EXAMINATION
filter
number
88
Spectral color
range
Infra Red
Dark
Control
49
Microscopic appearance
Cells lack granular con­
tents and colored pigments
Cells more or less disin­
tegrated; few colonies
Cells lack granular con­
tents and had whitishyellow color instead of
bluish-greeh*
Cells
scattered like as In
infra red culture* Pew
cells In colonies
Blue s-Blue-Gre en
Plant body cells undevel­
oped, and a few cell
walls ruptured.
Few cells
In colonies
5&
Without a doubt, the cultures exposed to the deep
red and greens spectral regions had much more growth than
any of the other cultures.
The remainder appeared to have
only slight differences in quantities of algal growth with
the exception of those grown in darkness and the ones ex­
posed to infra red and blues-blue-green rays.
The dark
control culture had a distinct yellowish-green appearance
and the plants were not united in large masses, which is a
distinguishing mark of the genus Gloeothece.
Instead, the
cells were widely scattered over the bottom of the culture
flask, giving the appearance of a very scanty growth.
The
culture exposed to the infra red rays was similar to the
culture grown in the dark, with the exception that growth was
slightly more abundant
than in the dark control.
The only
feature concerning the culture exposed to the blues-bluegreen was the minute quantity of growth; otherwise, no u n ­
usual appearance was noticeable.
Table X presents, in a concise form, the general
appearance of the 13 cultures of the blue-green alga when
placed over the fluorescent lamp (Figures 8 and 9).
57
TABLE X
THE EFFECT OF VARIOUS LIGHT RAYS ON THE BLUE-GREEN
A L G A > GLOEOTHECE, AS DETERMINED B Y GENERAL APPEARANCE
Filter
number
Spectral color
range
General appearance
70.
Deep Red
Abundant growth; bluishgreen color; plants in
one large, united mass
61.
Green-Yellow-Green
Abundant growth; bluishgreen color; plants in
several large masses
29.
Oranges-Reds
Abundant growth; bluishgreen color; cells in
one mass
Light
Control
Full
Medium growth; cells
closely united in one
mass; bluish-green color
71.
Orange-Red
Abundant growth; bluishgreen color; plant masses
easily separated by gently
shaking the flask
74.
Pure Green
Medium growth; bluishgreen color; cells tightly
united in one mass
75.
Blue-Green
Growth and appearance
similar to Nos* 73 and 74
58
TABLE X (CONTINUED)
THE EFFECT OF VARIOUS LIGHT RAYS ON GLOEOTHECB
AS DETERMINED B Y GENERAL APPEARANCE
Filter
number
Spectral color
range
General appearance
76*
Violet
Growth very poor; color
of plants more of a yellow­
ish green; cells separated
Into small clumps
73
Yellow-Green
Medium growth; bluishgreen color; growth
appears somewhat flimsy
72
Or ang e -Ye 11 ow
Medium growth; bluishgreen color; plant masses
easily separated by gently
shaking the flask
88
Infra Red
Growth similar to No* 76,
except that the yellowish
color was more predominate
Dark
Control
49
Growth similar to No* 88.
Bluish-green color lacking;
Instead, a whitish-gray
Blues-Blue-Green
Growth scanty; bluishgreen color; cells in one
small mass
FIGURE 9.
Photographs showing the quantities of
growth in the 12 culture flasks and
the device used to determine the growth
by general appearance.
59
FIGURE 10*
Photograph showing the comparative
quantities of algal growth In the
light and dark controls*
FIGURE 50.
61
CHAPTER VI
SUMMARY OP PROCEDURE AND RESULTS
I.
PROCEDURE
Eleven Wratten light filters, of known density and
wave-length transmissions (Table I in text, Figures 9, 10
and 11 in supplement), were purchased from the Eastman
Kodak Company to determine the effect of varying the quality
of fluorescent light on the growth of the blue-green alga,
Gloeothece rupestris (LyngbJ B o m #
Each filter was placed
over a 1*5 inch circular opening in the bottom of a culture
filter box, constructed in a light-proof manner so that the
only light permitted to enter had first to pass through the
Wratten filter#
Wide-mouthed Erlenmeyer flasks of 260 cc#,
containing the blue-green alga cultures, were placed in
these culture boxes (Figure 3)#
In order to insure uniform distribution of the algal
cells in the individual culture flasks, 150 cc. of suspended
blue-green algal cells were poured into a 3-liter pyrex
flask containing Detmer’s nutrient solution diluted one to
two (Table II)#
After a period of 24 hours the 3-liter
flask was gently shaken and 150 cc# of the suspended cells
were poured Into each 250 cc# Erlenmeyer flask and sealed
with sterilized cotton plugs#
62
The distances from the source of light were varied,
depending upon the transmissibility of the radiant energy
of the respective Wratten light filters, in order to main­
tain an exposure of all cultures except the dark control to
uniform light intensity of various qualities*
Each filter was placed over the entire face of a
photoelectric photometer and, with the aid of a yardstick
ruler, the light intensity of the transmitted radiant energy
through each filter was recorded at one-inch distances above
the fluorescent lamps to determine the light intensity of
the 11 Wratten filters and select an intensity for standard
use with all cultures except the dark control (See Tables
XI to XX, inclusive, in the supplement).
Since the photo­
electric cell varies in the relative spectral sensitivity to
various wave-lengths of light, the sensitivity of each wave­
length employed was determined from Figure 7.
Thus, the
exact light intensity transmitted by each light filter was
interpreted from these two sources of data.
Five microamperes, the lowest reading at a point one
inch above the fluorescent lamps, was considered the standard
light intensity for all 12 cultures, which included the full
light control.
A dark control was also maintained, making
a total of 13 cultures.
The culture filter boxes were ad­
justed at the various levels according to the transmission
of the respective filters, and, in this manner, each culture
received 5.0 microamperes of light intensity.
Dr. Richard E. Vollrath, of the Department of Physics,
in the University of Southern California, not only suggested
but recommended the use of a calorimeter (Figure 2) to deter­
mine the radiant energy transmitted b y the filters at the
standardized heights above the light source.
The Wratten
filter to be analyzed, was removed from its culture box and
placed in its proper position on the calorimeter, which was
then held level with the bottom of the box from which the
filter was removed.
At the end of 30 seconds of exposure
the radiant energy was recorded (Table XV).
Growth of the blue-green alga in the various cultures
was interpreted from results obtained from 4 sources of data:
(1) the microscopic cell count; (2) the increase or decrease
of microamperes as determined by the turbidity of the algg.1
growth in the nutrient solution;
(3) the microscopic examina­
tion of the algal cells from each alga culture in relation
to the morphological changes; and (4) by the general appear­
ance of the plants in the individual flasks.
Seven fluorescent lamps (Figure 4) were used as a
source of radiant energy possessing certain desirable feat­
ures, as (1) the similarity of its spectrum with that of
natural daylight; (2) the lack of concentrated heat in one
spot; (3) greater light intensity with less heat than that
found in incandescent lamps; and (4) the uniformity of light
distribution.
These lamps were turned on at 9:00 A. M* and
turned off at 9:00 P. M., thus daily exposing the blue-green
alga cultures to light for 12 continuous hours*
In the summary of results, the characteristics of
the cultures showing the best growth will be contrasted
with those showing the poorest growth*
This contrast will
be followed by a description of the cultures showing inter­
mediate growth, with a statement of interpretation*
II*
RESULTS
According to methods employed in this investigation
to determine the effect on the blue-green alga, Gloeothece
rupestrls, of varying the quality of fluorescent light
without varying its Intensity, the results show: (l) that
the deep red and greens of the visible spectrum are bene­
ficial and stimulate growth; (2) that the blues and bluegreens not only greatly hinder growth but actually destroy
the plant cell bodies;
(3) that cultures exposed to infra
red and violet rays are characterized by lack of growth
and chlorophyll*
Conditions of similar nature were found in the culture
maintained in darkness, with the exception that the plant
mass had a whitish-yellow appearance instead of the usual
bluish-green color; and (4) that cultures exposed to the
oranges-reds, orange-red, pure green and blue-green spec­
tral regions maintained approximately uniform quantities of
growth and color characteristics, with the exception of the
cultures exposed to the oranges-reds and orange-red of the
65
spectrum.
Increases in cell population in these cultures
were slightly greater than in the other cultures which
were exposed to pure green and blue-green spectral regions*
The results further show that the best growth among
the various cultures appears to occur in the red portion of
the spectrum which is of high energy value, rather than those
cultures which were exposed to the greens of the spectrum
that are of lower energy value*
It may therefore be con­
cluded that the quality of light is more important than
energy value in the growth of the blue-green alga,
Gloeothece rupestris *
66
S U P
E L E M E N T
67
TABLE XI
DATA ON DETERMINATIONS OF LIGHT INTENSITY OF
WRATTEN FILTER NO. 29. ORANGES-REDS (680-700A°)
1.
12.3
2.
12.0
3.
11.4
4.
11.0
5.
10.9
6.
10.1
7.
9.5
8.
9.1
9.
8.7
8.3
11.
8.0
7.7
13.
7.0
14.
6.1
15.
5.9
16.
5.5
17.
5.0
H
oo
•
4.0
19.
3.1
w to
o
H
• !•
j
H
to
•
h
o
•
i
i
i
i
Microamperes
;
|
Inches
1.5
0.9
22*
0.
68
TABLE XII
DATA ON DETERMINATIONS OP LIGHT INTENSITY OP
WRATTEN FILTER NO. 49.
BLUES-BLUE-GREENS
(350-610A0 )
Inches
Microamperes
1.
10.1
2.
10.0
3.
9.0
4.
8.0
5.
8.0
6.
8.0
7.
5.0
8
.
5.0
2.0
H
O
•
9.
1.0
11 •
0.9
12.
0
.
69
TABLE XIII
DATA ON DETERMINATIONS OP LIGHT INTENSITY OP
WRATTEN FILTER NO. 61.
GREENS (485-610A0 )
Inches
Mi croamperes
1.
9.9
2.
9.7
5*
9.5
4.
9.3
5.
9.0
6.
8.9
7.
8.2
8*
7.9
9.
7.4
H
H
•
•
O
H
7.0
6.1
12.
5.0
13.
4.2
14.
3.0
15.
2.5
16.
1.0
17.
0.9
18.
0.
70
TABLE XIV
DATA ON DETERMINATIONS OF LIGHT INTENSITY OF
WRATTEN FILTER NO. 70. DEEP RED (680-700A°)
Inches
Microamperes
1.
9.0
2.
8.0
3.
o
•
to
4.
2.5
5.
1.0
6.
0.9
7,
0
.
71
TABLE XV
DATA ON DETERMINATIONS OP LIGHT INTENSITY OP
WRATTEN FILTER NO. 71. ORANGE-RED (580-700A°)
Inches
Microamperes
1.
9.0
2.
8.0
5.
5.0
4.
5.0
5.
3.5
6.
2.0
7*
1.5
8.
1.0
9.
0.9
10.
0.
72
TABLE XVI
DATA ON DETERMINATIONS OP LIGHT INTENSITY OP
WRATTEN FILTER NO. 72. ORANGE-YELLCW(580-700A°)
Microamperes
1*
5.0
2.
2.0
5.
2.0
4.
H
•
O
Inches
5.
0.9
6*
0.7
7.
to
•
o
8.
0.
73
TABLE XVII
DATA ON DETERMINATIONS OF LIGHT INTENSITY OF
WRATTEN FILTER NO. 73.
YELLCW-GREEN
(680-700A°, 550-625A°)
Inches
Microamperes
1.
5.0
2.
4.0
3.
2.0
4.
1.0
5.
o.
H
6.
0.9
7.
0
.
74
TABLE XVIII
DATA ON DETERMINATIONS OP LIGHT INTENSITY OP
WRATTEN FILTER NO# 74, PURE GREEN (510-575A0 )
Inches
Microamperes
1#
9.0
2#
5.0
3#
5#0
4#
3.0
5.
2.0
6#
1.1
7.
0.9
8#
0.
75
TABLE XIX
DATA ON DETERMINATIONS OF LIGHT INTENSITY OF
WRATTEN FILTER NO. 75.
BLUE-GREEN
(475-540A0 , 690-700A°)
Inches
Microamperes
1.
o
.
o
H
2.
9.0
3.
O
•
00
4.
5.0
5.
4.9
6.
3.0
7.
2.3
8.
1.3
9.
1*0
10.
0.9
.
11
0
76
TABLE XX
DATA ON DETERMINATIONS OF LIGHT INTENSITY OF
WRATTEN FILTER NO. 76.
VIOLET
(682-700, 330-480A°)
Microamperes
H
H
H
3.
11.0
4.
10.0
5.
9.0
6.
8.0
7.
5.0
8.
5.0
9.
4.1
•
O
3.0
11.
2.2
o•
2.
1
1.
H
to
o
Inches
H
to
.
12.
13.
0.9
14.
0
77
TABLE XXI
DATA ON DETERMINATIONS OP LIGHT INTENSITY OP
WRATTEN FILTER NO, 88. INFRA RED (680-700A°)
Inches
Microamperes
1.
5.0
2.
3.0
3.
2.0
4.
1.1
5.
0.9
6*
0.4
7#
0
.
78
TABLE XXII
DATA ON DETERMINATIONS OP LIGHT INTENSITY
OP LIGHT CONTROL
Inches
Microamperes
1#
2.
S.
22.0
19.5
18.0
4.
5.
17.0
16.7
6.
15.5
7.
14.6
8#
15.5
9.
15.0
•
o
11.
11.5
10.5
•
to
10.0
14.
9.4
15.
8.4
16.
8.0
17.
7.5
18.
7.0
19.
6.5
20.
5.9
21.
5.9
22.
5.5
25.
5.2
24.
5.0
25.
4.2
26.
3.1
27.
29.
2.0
1.0
0.9
50 .
0.1
H
to
•
H
12.1
i
I
1
j
to
CD
.
H
TABLE XXIII
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 29.
ORANGES-RED
Initial Reading. March 13, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
1.
4.
0.
2.
0.
2.
0.
0.
0.
3.
4.
64.
64.
64.
2.
0.
1.
0.
5.
Total
64.
320.
2.
6.
6.
12.
0.
Average No. of
cells per square .•
1.
.040
Average No. of
cells in culture flask
........
9,600,000
Final Reading, April 6, 1940.
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
0.
0.
4.
2.
64.
4.
8.
1.
3.
64.
2.
2.
0.
4.
64.
1.
4.
0.
5.
64.
0.
0.
0.
Total
320.
7.
14.
5.
Average No. of
cells per square ••
.059
Average No. of
cells in culture flask ...........
14,160,000
80
TABLE XXIV
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 49. BLUESBLUE- GREENS
Initial Reading, March 13, 1940.
Fields
counted
Colonies
per field
Squares
counted
Algal cells
in colonies
Algal cells
in free state
1.
64.
3.
9.
0.
2.
64.
0.
0.
0.
3.
64.
2.
2.
1.
4.
64.
0.
0.
0.
5.
64.
0.
5.
0.
1.
11.
2.
Total•
320.
Average No. of
cells per square .............
..•••
Average No. of
cells in culture f l a s k ........................
.040
9,600,000
Final Reading, April 6, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
0.
0.
1.
2.
64.
0.
0.
0.
3.
64.
3.
6.
0.
4.
64.
0.
0.
0.
5.
Total
64.
320.
0.
3.
0.
6.
1.
2.
Average No of
cells per square ••
.025
Average No. of
cells in culture flask
6 ,000,000
TABLE XXV
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 61.
GREENS
Initial Reading. March 15, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1*
2.
64.
64.
0.
3.
0.
3.
3.
0.
3.
64.
0.
0.
2.
4.
64.
0.
e.
0.
5*
Total
64.
320.
0.
3.
0.
3.
1.
6
Average No. of
cells per square • •••«
.028
Average No. of
cells in culture flask ••. .......
6,720,000
Squares
counted
1.
64.
0.
0.
0.
2.
64.
6.
9.
0.
3.
64.
0.
0.
2.
4.
o>
•
Fields
counted
Final Reading, April 6. 1940.
Algal cells
Algal cells
Colonies
per field
in colonies
in free state
0.
0.
0.
5.
Total
64.
320.
0.
6.
0.
9.
5.
7.
Average No. of
cells per square •••••
.050
Average No. of
cells in culture flask ..........
12,000,000
TABLE XXVI
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 70.
DEEPRED
Initial Reading , March 13. 1940
•
Fields
counted
Algal cells
in colonies
Colonies
per field
Squares
counted
Algal cells
in free stat<
1.
64.
4.
8.
0.
2.
64.
2.
4.
0.
3.
64.
0.
0.
3.
4.
64.
0.
0.
0.
5.
64.
0.
0.
1.
320.
6.
13.
4.
Total•
Average No. Of
cells pe)r square
.053
Average No. of
cells in culture flask
............
12,720,000
Final Reading, April 6, 1940
Fields
counted
Squares
counted
1.
64.
0.
0.
2.
2.
64.
4.
«
o
H
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
0.
3.
64.
2.
4.
1.
4.
64.
0.
0.
0.
5.
64.
3.
3.
1.
Total
320 .
9.
17.
10.
Average No. of
ftAlla n a r
______
Average No. of
cells in culture flask
.084
20,600,000
83
TABLE XXVII
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO, 71.
ORANGERED
Initial Reading , March 13, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells in
free state
1.
64.
2.
4.
1.
2.
3*
4.
5,
64*
64.
64.
64.
0.
0.
2•
0.
0.
0.
2.
0.
320.
4.
6.
0.
2.
0.
1.
4.
Total•
Average No. of
cells £er square «
.031
Average number of
cells In culture flask
7,440,000
Final Reading, April 6, 1940
Fields
counted
1.
2.
3.
4.
5.
Total•
Squares
counted
Colonies
per field
Algal cells
In colonies
Algal cells in
free state
64.
0.
0.
3.
64.
64.
64.
64.
320.
2.
0.
0.
2.
4.
5.
0.
0.
3.
8.
0.
0.
1.
0.
7.
Average No. of
cells per square
.046
Average No. of
cells in culture flask ••••••
11,040,000
84
TABLE XXVIII
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO* 72* ORANGEYELLOW
Initial Reading, March 15« 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
64.
2.
6.
0.
2.
64.
0.
0.
0.
3.
64.
0,
0.
3.
4*
64.
2.
4.
0.
5,
Total
64,
320,
0.
4.
0.
0.
3.
•
o
H
1.
Average No. of
cells per square ••.*•
.040
Average No. of
Cells in culture flask ........ .
9,600,000
Final Reading, April 6, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
64.
0.
0.
0.
64.
2.
4.
1.
3.
64.
0.
0.
5.
4.
64.
0.
0.
0.
5.
Total
64.
320.
0.
2.
0.
4.
4.
H
O
.
1.
2.
Average No • of
cells per square ...
.043
Average No, of
cells in culture flask
10,320,000
TABLE XXIX
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO* 73. YELLCWGREEN
Initial Reading* March 15* 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
3.
3.
0.
2.
64.
0.
0.
0.
3.
64.
0.
0.
2.
4.
64.
2.
4.
0.
5.
Total
64.
320.
0.
5.
0.
7.
0.
2.
Average No « of
cells per square •...*
.028
Average No. of
cells in culture flask ..........
6,720,000
Final Reading, April 6* 1940
Fields
counted
Square
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
0.
0.
2.
2.
64.
2.
5.
0.
3.
64.
0.
0.
1.
4.
64.
64.
320.
2.
0.
7.
0.
5.
Total
1.
0.
3.
Average No* of
cells per square
......................
Average No. of
cells in culture flask
1.
4.
.034
8,160,000
TABLE XXX
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 74.
PURE
GREEN
Initial Reading. March 13. 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1*
64.
0.
0.
4.
2.
64*
3.
4.
0.
3.
64.
0.
0.
2.
4*
64.
0.
0.
0.
5.
Total
64.
320.
0.
3.
0.
4.
0.
6.
Average No • of
cells per s quare .♦ . ..
.031
Average No. of
cells in culture flask ..........
7,440,000
Final Reading, April 6, 1940
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
0.
0.
0.
2.
3.
64.
8.
6.
64.
0.
0.
3.
4.
4#
64.
2.
2.
0.
5#
64.
0.
0.
Total
320.
|-i
o
•
Fields
counted
8.
0.
7.
Average No • of
cells per square •«
.046
Average No. of
cells in culture flask
11,040,000
TABLE XXXI
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 75. BLUEGREEN
Initial Reading, March 15, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
64.
3.
9.
0.
2.
64.
0.
0.
0.
3*
64.
1.
2.
1.
4.
64.
0.
0.
0.
5.
Total
64.
320.
0.
4.
0.
1.
2.
•
H
H
1.
Average No. of
cells per square
...
*040
Average No* of
cells in culture flask ........................... 9,600,000
Final Reading, April 6, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
In colonies
Algal cells
in free state
1.
64.
0.
0.
3.
2.
64.
2.
6.
0.
3.
64.
0.
0.
1.
4.
64.
0.
0.
1.
5.
Total
64.
320.
2.
4.
2.
8.
0.
8.
Average No . of
cells per s quare ...
.050
Average No. of
cells in culture flask
12 ,000,000
TABLE XXXII
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 76. VIOLET
Initial Reading, March 13, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
In colonies
Algal cells
In free state
1#
64.
0.
0.
5.
2.
64.
2.
2.
0.
3.
64.
0.
0.
1.
4.
64.
0.
0.
2.
5.
64.
0.
0.
0.
2.
2.
8.
Total
320
Average No. of
cells per square •
.031
Average No. of
cells in culture flask ..........
7,440,000
Final Reading, April 6, 1940
Algal cells
in colonies
Fields
counted
Squares
counted
Colonies
per field
1*
64.
4.
8.
0.
2.
3.
4.
64.
64.
64.
0.
0.
2.
0.
0.
2.
0.
0.
0.
5.
Total
64.
320
0.
6.
0*
1.
3.
Algal cells
In free state
•
o
H
Average No. of
cells per square •••••••••••••••••
.040
Average N o • of
cells in culture flask ...........
9,600,000
TABLE XXXIII
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH WRATTEN FILTER NO. 88.
INFRA
RED
Initial Reading, March. 13, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
0.
0.
3.
2.
64.
0.
0.
0.
3.
4.
64*
4.
5.
0.
64.
0.
0.
0.
5.
Total
64*
320.
0.
4.
0.
5.
1.
4.
Average No • of
cells per s quare ...
.028
Average No. of*
cells in culture flask
..................
6,720,000
Final Reading, April 6, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
1.
64.
2.
4.
1.
2.
3.
64.
64.
0.
0.
0.
0.
3.
0.
4.
64.
2.
2.
0.
0.
4.
0.
6.
0.
4.
5.
64.
Total
320.
Average No • of
cells per square • • • • •
Average No. of
cells in culture flask ..........
.031
7,440,000
TABLE XXXIV
CELL POPULATION IN CULTURE EXPOSED TO DARKNESS
Initial Reading, March 15, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
In free state
64.
2.
8.
0.
2.
64.
0.
0.
1.
3*
64.
0.
0.
2.
4.
64.
1.
2.
0.
5.
Total
64.
320
0.
3.
0.
1.
4.
.
o
H
1.
Average No . of
cells per s quare ••••••
.043
Average No. of
cells In culture flask
10,320,000
Final Reading, April 6, 1940
Algal cells
In colonies
Algal cells
In free state
1 .
64.
0 .
0.
3.
2.
64.
64.
0 .
0 .
4.
3.
0 .
0 .
4.
64.
2.
2.
3.
5.
Total
64.
0 .
0 .
0 .
2.
2.
•
H
|
i!
320
3.
Average No. of
cells per square ......
.046
Average No. of
cells in culture flask
11,040,000
t
Colonies
per field
1
Squares
counted
I
Fields
counted
91
TABLE XXXV.
CELL POPULATION IN CULTURE EXPOSED TO RADIANT
ENERGY THROUGH LIGHT CONTROL
Initial Reading, March 13, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
in colonies
Algal cells
in free state
0.
0.
5.
3.
64.
64.
2.
3.
2.
6.
0.
0.
4*
64.
0.
0.
0.
5.
Total
64.
320.
2.
7.
4.
0.
5.
H
to
•
64*
1.
2.
Average No. of
cells per square
.053
Average No. of
cells In culture flask ..........
12,720,000
Final Reading, April 6, 1940
Fields
counted
Squares
counted
Colonies
per field
Algal cells
In colonies
Algal cells
In free state
64.
4.
8.
1.
2.
64.
6.
6.
3.
3.
64.
2.
4.
0.
4.
64.
0.
0.
0.
5.
Total
•
to
0.
0.
0.
320.
6.
18.
4.
i
1.
Average No. of
cells per square •
.068
Average No. of
cells in culture flask •••••«••••<
16,320,000
FIGURE 11.
Wave-length absorption and transmission
of filters Nos* 29, 49, 61 and 70*
II eanSi^
o
t r a n s m is s io n
dcnsity
W'KATTKN
I.N.HT
Figure
TRANSMISSION
DENSITY
Fll/l'K ltS
12.
No. TO. a-(Contrast R)
36
o
FIGURE 12*
Wave-length absorption and transmission
of filters Nos* 71, 72, 73 and 74.
•21 ©an S^
©
a?
o
TRANSMISSION
-
cT
-
§
ae
o
TRANSMISSION
<je
-
1.
DENSITY
WRATTEN
Figure
LIGHT
12,
FILTERS
S6
FIGURE 13*
Wave-length, absorption and transmission
of filters Nos. 75, 76 and 88.
O
T R 4 N 5 MISSION
o
O "RA NSMISSION
TRANSMISSION
200
DENSITY
300
400
500
600
TOO
<0
95
LITERATURE CITED
Brooke 3?, Klugh.
1925#
New Phytologist.
London.
Chamberlain, T. C.
1916.
The Origin of the Earth.
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652 Pp.
Vol. 24, No. 3.
Pp. 186-190.
Chicago: Houghton Mifflin
Dangeard, P. A.
1927.
Recherches sur 1 T assimilation chlorophyllienne et
les questions qui s fy rattachent. Le Botanists.
Ser. 19.
397 Pp.
Duggar, M. B., Editor in Chief.
1936.
Biological Effects of Radiation. Vol. 2. New York
and London: MeGraw-Hill Book Company, Inc. 1340 Pp.
Pair, M., and Gordon Whipple.
1927.
Microscopy of Drinking Water. Fourth edition.
York: John Wiley and Sons, Inc.
Pp. 45-74.
New
Fritsch, F. E.
1935.
The Structure and Reproduction of the Algae. Vol. 1.
New Y o r k : The MacMillan Company.
Pp. 11-15.
Gardner, N. L.
1906.
Cytological Studies in Cyanophyoeae♦ Vol. 2, No. 12,
November 10. University of California Press,
Berkeley. Pp. 237-296.
Grintzesco, J.
r
1903.
*Contribution a fl*etude des Protijcqccacees, Chlorella
vulgaris.** Seyerinck.
Revue Generale de Botanlque.
tome 15.
Paris.
Pp. 5-19.
Harder, R.
1923.
Zeitschrift fur Botanik.
Jena.
Vol. 15. Pp. 305-320.
Iggena, M. S.
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