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Radioecology
Eatimates
‘
dose - 50's
lethal
of
of
Table 5.
Wisgurous
Responses of amphibian embryos and larvae to
X-rays, modified from data of Rugh (1954).
embryos based upon Seecripticns
.
fuasilis
ents by Belyaeva
Subjective estimates of lethal dose-50 are
based on Rugh‘'s description of effects.
geirr diation experim
1958) at four stages
and Pokrovakaya@ (1957,
of development (referred to Solberg's 1938
ying).
time table for Fundulus for quantif
of
Lrradiated
Estimated
lethal
dose-50
Ver
cent
id
at
pneu-
vation Year
Btateu
Aba lophasc 0.57
tet
:
Me leavsue
: a iopnaxc 0.85
c.
na-
meleavaxon
r 2-3
Early
z.3
5.3
1958
Figures
la and ib
Table
1
1957 Table
300
200 roentgens,
hatching ,but
abnormal forms
found;500 roentgens,some larvae
hatch, abnormal.
1
500 roentgens,
all hateh;1,000
roentgens,
majority hatch.
age
2
-042
3
.15
1,200
esulting lethal dose-50's at metamorphosis appear
Hn Table 5.
The relationship of lethal dose-50's
-Newly fertilized egg(sperm
enters egg):150 roentgens, 50
per cent developed normally....150
.0144-Polar body extrusion(19 min-
utes) :300 roentgens ,developed
only to yolk plug stage........150
047 +~Zygote: 300 roentgens, 16 per
cent gastrulated, then died....200
.167 -2-cell, 2} hours:300 roent-
.4
gens, reached late gastrula
54 per cent neurulated......... 200
-Blastula, 16-many-celi1;: 180
roentgens, lived indefinitely;
360 roentgens, 70 per cent
had nerve Cord... ..e. cece eee 200
-Gastruia:300 roentgens, developed to external gilli
.44
1]
1.47
1.63
12
21.75
41.94
13°
62.1
2.33
-
19
4.9
5.4
21
6.8
7.6
23
49.0
10.0
O percentage of the period from fertilization to
tamorphosis at the time or irradiation is plot-
ed in Figure 4 along with the relationship for
ndulus.
For amphibia’ two trends are evident, a
low increase in radioresistance in the early sta-
mes up to the time of neurulation (two per cent of
ehe premetamorphic per lod) expressed by the logari-
hmic equation Y = 229 X0.0712 followed after
40 60
meurulati n by a more rapid increase in resistance,
‘yy « 185
-6
Hatching, at 5.4 per cent of the
ppremetamorphic period, appears not to affect the
wate of increase in radioresistance.
67
flexure..... ae ewe ee tenes 290
-Yolk plug stage: 300 roentgens, died at 9 days...........200
-Neurula:300 roentgens, some
outlived duration of experi-
ment...... wee eee ee enews 360
-~Hatching: 300 roentgens, no
effect; 600 roentgens, 54
per cent lived 5 days.......... 500
-Early external gill stage: 500
roentgens,survived 3 months
to metamorphoris;1,000 roentgens, survived 7 days.......... 700
Absorbing external, and
growing internal, gills:1,000
roentgens, indefinite survival;
2,000 roentgens,20 per cent
died in 8 days; 15,000 roentgens, 50 per cent died in 9
GAYS... ccc cee ene et eee 1,500
-Premetamorphosis......... 1 eed, 000
Regression of lethal-dose-50 upon per cent of development from fertilization
of the @gg to hatching, for fish, or to metamorphosis, for amphibia.
Lethal dose-50 (y)
in terms of per cent development (x) when irradiated
Using calculated lethal dose-50
om
wh
e
}
“nwa
WeOrganinm
)
aaiaon
inbow
Mrnus
iy
FY
alles
when
lethal
dose-50 was
hatching
Rugh and
hatching
@od of yolk
150 days
Clugston
hatching
Belya
Pokrovmkaye etching
Rugh
metamorphosis
ia the
: Baatiticen ana
o
b
$
~
~
+a
gow
d
wvAAY
UO
+t
Oo e
38& 34 2°S
20
fitted
lo
20
240
4
6
179
131
21
125
Using estimated lethal dose-50
et
a
red
d¢au
ec
~~
ao
a
3
a
«ea
of
om
~
ea
ga~
wrt ®
Paw
oa
“et
ano
ov
co
&
mo a
£23
B®
2
wthority determined 2 8 288 255 tos
Present)
We lander
trout
;
Stage
A
.421
.331
457
.390
t
+t
Pp
1.194
4.56 <.001
547
.231
3.59
4.68
.188
3.68
<.005
<.08
<.01
-
(preneurulation)
(postneurulation)
5
Od
HAH
oa
pas
Bo
e282
a°S
geo
225
we
2
23
393
.398
.137
5.83
<.001
6
6
198
163
.612
.390
.245
.214
6.92
5.04
<.005
<.01
.698
415
5.35
< .02
28 BSH 885 tos
23
4
4
7
5
187
394
214
241
185
=.390
t
4135
of
t
+P
6.460
.469
.149 13.7
.925 1.62
2.33
.0896 .0794 2.90
i
Rartthmic
equation, y = ax?.
subtraction
(roentgens)
larvae,but with ventral tail
Oo metamorphosis, a pericd of 90 days.
Some of
is descriptions pertaining to the lower doses, and
ur own estimates from these descriptions of the
Table 6.
Description and results
a
-013
6-8
300
days
(0
1
100
1958 Figure 2
1957
o
(roentgens)
Description
Source
No.
hatching
Per
cent
of 90
Days
of
Estimated
lethal
dose-50
at metamorphosis
.055p from b give the .05 confidence interval.
poe Ah
< 001
<.01
<.2
<.05