Studies relating to seed set and germination in umbellifers


Sehgal, C.B.

Proceedings of the National Institute of Sciences in India Part B Biological Sciences 34(1): 60-70

1968


The maximum seed-set in Ammi majus, Anethum graveolens, Coriandrum sativum, Cuminum cyminum, Daucus carota, Foeniculum vulgare and Trachyspermum ammi is in the umbels of the first orders, and it declines in the umbels of higher order. The factors responsible for the low seed-set are male flowers, underdeveloped flowers and lack of pollination or fertilization. The seeds2 require a low temperature (15 to 25° C) for germination. The poor germination is mainly due to (a) abortion of seeds due to lack of pollination or fertilization, (b) attack of insects on the post-fertilized ovaries causing embryolessness and (c) seeds with rudimentary, dormant or defective embryos.

STUDIES
RELATING
TO
SEED
-SET
AND
GERMINATION
IN
UMBELLIFERS
by
C.
B.
SERGAL,
Department
of
Botany,
University
of
Delhi,
Delhi
7,
India
(Communicated
by
B.
M.
Johri,
F.N.I.)
(Received
October
11,
1966)
The
maximum
seed
-set
in
Ammi
majus,
Anethum
graveolens,
Coriandrum
sativum,
Cuminum
cyminum,
Daucus
carota,
Foeniculum
vulgare
and
Trachy-
spermum
ammi
is
in
the
umbels
of
the
fi
rst
orders,
and
it
declines
in
the
umbels
of
higher
order.
The
factors
responsible
for
the
low
seed
-set
are
male
fl
owers,
underdeveloped
fl
owers
and
lack
of
pollination
or
fertilization.
The
seeds2
require
a
low
temperature
(15
to
25°
C)
for
germination.
The
poor
germination
is
mainly
due
to
(a)
abortion
of
seeds
due
to
lack
of
pollination
or
fertilization,
(b)
attack
of
insects
on
the
post
-fertilized
ovaries
causing
em-
bryolessness
and
(c)
seeds
with
rudimentary,
dormant
or
defective
embryos.
INTRODUCTION
One
of
the
serious
problems
in
the
umbellifers
is
low
seed
-set
which
reduces
the
yield.
Flemion
and
Waterbury
(1941)
found
that
low
seed
-set
in
Anethum
graveolens
was
due
to
the
attack
of
Lygus
bug
on
the
developing
ovaries.
According
to
Kho
and
Braak
(1956)
and
Braak
and
Kho
(1958),
in
addition
to
infestation
by
Lygus,
lack
of
proper
pollination
and
fertilization
also
reduced
the
seed
-set
in
Daucus
carota.
Gupta
(1964)
observed
that
in
umbellifers
the
low
seed
-set
is
mainly
due
to
insect
infestation.
As
early
as
1892,
Saunders
3
stated
that
the
seeds
of
carrots
showed
only
43
per
cent
germination
while
those
of
celery
failed
to
germinate.
About
15
years
later,
Fraser,
Gilmore
and
Clark
(1907)
3
reported
that
about
80
seeds
had
to
be
sown
for
each
carrot
harvested.
Hicks
and
Key
(1898)
emphasized
the
role
of
temperature
and
li
ght
in
the
germination
of
seeds
of
celery.
Hopkins
(1928)
confirmed
their
fi
ndings
and
stated
that
an
alternate
treatment
of
10
and
25°
C
resulted
in
maximum
germination.
However,
the
seeds
remained
in
a
semi
-dormant
state
at
a
constant
temperature
of
30°
C.
Taylor
(1949)
also
noticed
that
the
seeds
of
celery
failed
to
germinate
in
darkness
at
80°
F
(26.6°
C),
or
if
they
were
kept
alternately
at
70°
F
(21.1°
C)
for
4
hours
and
50°
F
(10°
C)
for
20
hours.
1
The
fi
rst,
second,
third
. .
.
order
of
umbels
refer
to
their
sequence
of
development
on
the
plant.
2
The
term
'
seed'
refers
to
only
one
mericarp
of
the
cremocarp
(see
Robinson
1954).
3
Cited
in
Robinson
(1954).
VOL.
34,
B,
No.
1.
SEHGAL
:
SEED
-SET
AND
GERMINATION
IN
II
MBELLIFERS
61
From
the
dormant
seeds
of
celery,
Hicks,
Doty
and
Quackenbush
(1951)
extracted
a
germination
inhibitor
which
was
proteinaceous
in
nature
but
its
exact
chemical
identity
could
not
be
established.
Stokes
(1953)
pointed
out
that
the
storage
of
seeds
of
Heracleum,
sphon-
dylium
at
2
to
C
accelerated
the
break
-down
of
proteinaceous
food
reserves
in
the
endosperm
to
amino
acids
(such
as
glycine
and
arginine)
which
stimulated
the
growth
of
embryo.
According
to
Borthwick
(1931)
and
Benei
(1949),
the
seeds
of
the
fi
rst
order
of
umbels
in
carrot
showed
better
germination
than
those
produced
on
other
umbels.
However,
Flemion
and
Henrickson
(1949)
did
not
fi
nd
any
such
correlation.
Harrington
(1951)
observed
that
in
carrot
the
spacing
of
seeds
during
sowing
did
not
have
any
effect
on
germination
(percentage
basis).
Flemion
and
her
co-workers
(1941-1955)
studied
the
causes
of
low
ger-
mination
in
several
genera
of
the
Umbelliferae
from
Denmark,
Holland,
N.
Africa,
Norway
and
U.S.A.,
and
observed
that
the
ungerminated
seeds
had
a
normal
seed
coat
and
endosperm
but
lacked
the
embryo.
Therefore,
they
concluded
that
in
the
maturing
fruits
visited
by
Lygus,
the
bug
consumed
the
young
embryo
causing
embryolessness.
Kho
and
Braak
(1956)
and
Braak
and
Kho
(1958)
confirmed
these
fi
ndings
in
Daucus
carota.
In
his
review
entitled
'Seed
germination
problems
in
the
Umbelliferae
Robinson
(1954)
mentioned
the
following
possibilities
for
low
germination
of
seeds:
(a)
(b)
(c)
embryolessness
in
seeds,
seeds
with
rudimentary
embryos
which
require
a
specific
period
of
storage
for
maturation
before
germination,
and
seeds
with
dormant
embryos
which
require
suitable
temperature
and
light
for
breaking
dormancy.
Gupta
(1962a,
b)
also
studied
the
causes
leading
to
embryolessness
in
the
seeds
of
umbellifers
and
pointed
out
that
embryolessness
is
caused
due
to
the
infestation
by
a
chalcid
fl
y,
Systole
albipennis
Walker,
which
lays
eggs
in
the
developing
ovaries.
These
eggs
develop
into
adults
at
the
cost
of
the
endo-
sperm,
embryo,
or
both,
and
fi
nally
escape
by
boring
a
hole
in
the
fruit
wall.
The
present
investigation
was
undertaken
to
study
the
factors
responsible
for
low
seed
-set
and
poor
germination
in
seeds
of
Ammi
majus
L.,
Anethum
graveolens
L.,
Coriandrum
sativum
L.,
Cuminum
cyminum
L.,
Daucus
carota
L.,
Foeniculum
vulgare
Mill.,
and
Trachyspermum
ammi
(L.)
Sprague.
MATERIALS
AND
METHODS
The
seeds
of
Ammi
majus,
Anethum
graveolens,
Coriandrum
sativum,
Cuminum
cyminum,
Daucus
carota,
Foeniculum
vulgare
and
Trachyspermum
ammi
were
obtained
from
various
places
in
India
through
the
courtesy
of
the
following
botanists:
62
Year
c.
B.
SEHOAL
Supplied
by
Place
1959,
1960
Dr.
A.
B.
Joshi
Delhi
1961,
1962
Dr.
M.
S.
Swaminathan
Delhi
1959
Professor
A.
K.
Mitra
Akola,
1960
Dr.
R.
P.
Roy
Patna
1960
Dr.
D.
D.
Pant
Allahabad
1960
Dr.
M.
R.
Suxena
Hyderabad
1960
Dr.
M.
H.
S.
Murthy
Rajkot
The
plants
were
raised
from
the
seeds
collected
from
Delhi,
while
the
seeds
obtained
from
various
places
in
India
were
used
for
the
study
of
insects.
For
investigating
anatomy
the
fl
owers
and
fruits
were
fi
xed
in
formalin-
acetic-alcohol
and
later
preserved
in
70
per
cent
ethanol.
The
material
was
dehydrated
in
alcohol-xylol
series,
embedded
in
paraffin
wax,
and
serial
sections
were
cut
at
10
to
15
Heidenhain's
iron-haematoxylin—
ery-
throsin,
and
safranin-fast
green
combinations
were
used
for
staining.
To
trap
the
insects
infesting
the
ovaries,
the
post
-fertilized
ovaries
of
Anethum,
Foeniculum
and
Trachyspermum
containing
cellular
endosperm
and
young
globular
proembryo
were
cultured
on
modified
White's
medium.
For
studies
on
germination
the
seeds
were
sown
on
moist
fi
lter
paper
or
sand
in
Petri
dishes.
One
hundred
seeds
were
sown
for
each
experiment,
and
each
experiment
was
repeated
thrice.
The
experiments
were
conducted
both
under
laboratory
conditions
(30
to
43°
C)
and
at
low
temperature
(15
to
25°
C).
After
determining
the
percentage
of
germination,
the
ungerminated
seeds
were
dissected
to
ascertain
the
fate
of
endosperm
and
embryo.
OBSERVATIONS
SEED
-SET
—The
fl
owers
in
the
umbellifers
investigated
are
minute
and
borne
in
compound
umbels.
Umbels
of
the
fi
rst
order
show
a
maximum
number
of
umbellets
and
there
is
a
gradual
reduction
in
the
number
of
um-
bellets
in
the
umbels
of
progressively
higher
order.
Initially
the
flowers
are
hermaphrodite
(Plate
IV,
fi
g.
1A,
B)
but,
due
to
the
suppression
of
gynoecium,
some
of
them
become
male
(Plate
IV,
fi
g.
1C).
Some
of
the
fl
owers
remain
underdeveloped
and
fail
to
open
(Plate
IV,
fi
g.
1D).
Even
in
the
bisexual
fl
owers
there
may
not
be
proper
pollination
or
fertilization
and
the
ovaries
may
shrivel.
All
these
factors
are
responsible
for
a
low
seed
-set.
In
Anethum
the
umbels
of
first
order
show
about
85
per
cent
hermaphro-
dite
and
the
rest
either
male
or
underdeveloped
flowers.
In
the
umbels
of
progressively
higher
order
there
is
reduction
in
the
percentage
of
hermaphro-
dite
flowers.
In
the
umbels
of
third
order
about
14
per
cent
fl
owers
are
hermaphrodite
and
the
rest
either
male
or
underdeveloped
(see
also
Sehgal
1965).
SEHGAL.
P
10,1
I—
0
v
A
F
Proc.
?win.
Inst.
Sri.
India,
Vol.
34,
B,
Plate
IV.
B
C
S
-;
A
p
VI"
E
PLATE
I
V
den
Fm.
IA
-II.
A
-D.
Traehy,sperinunt
fInuni;
.41.et11
fp'aceolen.c
(den,
degenerated
endosperm;
des,
degenerated
embryo
sac
e,
embryo;
ov,
ovary;
p.
petal).
A,
B.
herma-
phrodite
flowers.
6.
C,
D.
Male
and
underdeveloped
flowers,
respectively.
6.
E.
'mbel
of
the
`second'
order
showing
seed
-set
x
0.6.
F.
"I'mhellet
enlarged
from
E.
2.
C.
Upper
portion
of
mericarp
(Ls.)
showing
degenerated
embryo
sac.
x
198.
H.
Same,
showing
degenerated
proembryo
(note
the
absence
of
endosperm).
275.
The
umbels
of
first
order
show
maximum
seed
-set
because
these
umbels
contain
a
large
number
of
umbellets
and
higher
percentage
of
hermaphrodite
fl
owers
in
each
umbellet.
In
the
umbels
of
progressively
higher
order
the
seed
-set
is
low
because
there
is
a
gradual
reduction
in
the
number
of
umbellets
as
well
as
percentage
of
hermaphrodite
fl
owers
(see
Table
I;
Plate
IV,
fi
g.
1E,
F).
64
C.
B.
SEHGAL
TABLE
I
Seed
-set
in
umbels
of
different
orders
in
Anethum
Total
No.
of
No.
of
Average
Order
of
No.
of
No.
of
Seed
-set
No.
of
fertile
abortive
seed
-set
umbel
umbels
umbellets
T
o
seeds
seeds
seeds
o'
r.
First
1
24
880
456
424
51.8
51.8
Second
1
16
458
208
250
43.2
2
10
570
266
304
46.6
46.2
3
15
504
246
258
48.8
Third
1
10
300
26
274
8.6
2
17
414
30
384
7.2
3
12
324
18
306
5.5
4
11
340
10
330
2.9
6.1
5
12
348
12
336
34
6
10
304
28
276
9.2
Fourth
1
2
3
4
5
6
7
8
250
0
250
0.0
10
264
0
264
0.0
12
272
0
272
0.0
9
256
0
256
0.0
0.2
9
248
2
246
0.8
8
218
0
218
0.0
5
144
1
143
0.7
Thus,
the
maximum
seed
-set
is
51.8
per
cent
and
46.2
per
cent
in
the
umbels
of
the
fi
rst
and
second
order
respectively,
and
it
abruptly
drops
to
6.1
per
cent
and
0.2
per
cent
in
the
umbels
of
the
third
and
fourth
order,
respectively.
GERMINATION
—The
experiments
on
germination
tests
were
run
for
a
month
and
observations
recorded
daily
for
a
fortnight,
and
subsequently
on
alternate
days.
At
15
to
25°
C
the
freshly
harvested
seeds
(collected
in
the
month
of
May)
germinated
within
5
to
8
days
of
sowing,
but
there
was
no
germination
at
30
to
43°
C
(room
temperature
in
the
months
of
May
and
June).
It
appears
that
the
temperature
plays
an
important
role
in
the
germination
of
umbelliferous
seeds
(see
also
Hopkins
1928;
Stokes
1953).
The
results
of
germination
tests
are
presented
in
Table
II.
Thus,
it
is
clear
that
maximum
germination
(77
per
cent)
occurs
in
Ammi
and
minimum
(15
per
cent)
in
Cuminum.
Seeds
without
endosperm
and/or
embryo.
—Owing
to
the
failure
of
pollina-
tion
and
fertilization
the
ovules
abort.
Such
seeds
are
apparently
normal
but
lack
embryo
and
endosperm
(Plate
IV,
fi
g.
1G).
The
seeds
may
also
abort
if
the
growth
of
the
endosperm,
embryo,
or
both,
is
arrested
during
earlier
stages
of
SEED
-SET
AND
GERMINATION
IN
UMBELLIFERS
65
development
(Plate
IV,
fi
g.
1H).
Such
seeds
also
appear
normal
but
fail
to
germinate
(see
Table
II).
Sometimes,
when
the
embryo
sac
contains
cellular
endosperm
and
a
fi
lamentous
or
globular
proembryo,
a
chalcid
fl
y
(Systole
albipennis)
lays
an
egg
(rarely
two
or
three)
in
the
vicinity
of
endosperm
or
embryo
(Plate
V,
fi
g.
2
A
-D
;
Plate
VI,
fi
g.
3A).
This
egg
develops
into
an
adult
fl
y
at
the
cost
of
the
endosperm,
embryo,
or
both,
and
fi
nally
bores
a
hole
in
the
fruit
wall
and
escapes
(Plate
VI,
fi
g.
3B
-D).
This
is
the
chief
cause
of
embryolessness
in
the
seeds
of
umbellifers
collected
from
various
parts
of
India
(see
also
Table
II).
TABLE
II
Germination
results
Name
of
plant
Ger-
minated
seeds'
0/
/0
Aborted
ovules
0
0
Embryo
-
less
seeds
0
-
Dormant
or
rudi-
Defective
ment
ary
embryos
embryos
0/
/0
of
/0
1.
Ammi
majus
. .
77
10
3
6
4
2.
Anethum
graveolens
45
30
5
15
5
3.
Coriandrum
sativum
40
35
9
10
6
4.
Cuminum
eyminum
15
45
8
23
9
5.
Daucus
earota
. .
66
19
4
7
4
6.
Foeniculum
vulgare
52
18
11
12
7
7.
Trachyspermum
a
mmi.
61
15
5
10
9
1
Average
of
300
seeds.
To
trap
the
insects
infesting
the
ovaries,
the
post
-fertilized
ovaries
of
Anethum,
Foeniculum
and
Trachyspermum
containing
cellular
endosperm
and
young
globular
proembryo
were
cultured
on
modified
White's
medium.
Simul-
taneously
with
the
growth
of
the
embryo
in
cultures,
in
the
infested
ovaries
the
insect
egg
also
developed
into
the
adult
fl
y
which
escaped
from
the
fruit
wall
but
remained
entrapped
in
the
culture
tube
(Plate
VII,
fi
g.
4A).
These
chalcid
fl
ies
survived
for
6
to
10
days
inside
the
tube.
Beside
Systole
(Plate
VII,
fi
g.
4B),
the
entrapped
insects
also
included
two
parasites—Liodontomerus
(Family
Torymidae)
and
Tetrastichus
(Family
Eulophidae)
(Plate
VII,
fi
g.
4C).
Seeds
with
normal
endosperm
but
dormant,
rudimentary
or
defective
embryos.
—Some
seeds
contain
an
apparently
normal
embryo
but
fail
to
germi-
nate
due
to
dormancy.
At
the
time
of
harvesting
the
crop,
many
of
the
fruits
are
immature
and
the
seeds
contain
rudimentary
embryos
at
different
stages
of
development.
These
seeds
also
fail
to
germinate
(Table
II).
Occasionally,
the
cotyledons
are
either
suppressed
or
papery
and
such
embryos
with
an
unhealthy
appearance
have
been
referred
to
as
'defective'
embryos
(Plate
VII,
fi
g.
4D,
E).
SEHGAL.
Proc.
natn.
Inst.
Sci.
India,
Vol.
34,
B.
Plate
V.
'IN
1'
h.
p.
A
4,
.
?Sr
cr
..••••
....***
.
.."7
4
.t711'.:
1
!
F.
rf
Y.
A
JO
'
•••••
‘q.
do
FIG.
2
SEHGAL.
Proc.
natn.
Inst.
Sci.
India,
Vol.
34,
B,
Plate
VI.
CONCLUSIONS
Some
factors,
relating
to
seed
-set
and
germination
of
seeds
in
umbellifers
Ammi
mains,
Anethum
graveolens,
Coriandrum
sativum,
Cuminum
cyminum,
Daucus
carota,
Foeniculum
vulgare
and
Trachyspermum
ammi,
have
been
studied.
r
4.
•ir
r.
•LA
I
1
1
C
PLATE
VI
no.
3A
-D.
A,
C.
Foenieulunt
.rulgare:
B.
Anethum.
graveolens,
D.
Trachyspermum
ammi
(d1
1
to
di
3
,
developing
insects;
ho,
hole;
m
i
and
m
2
,
rneriearp0.
A.
Upper
portion
of
fruit
(1.s.)
showing
three
insects
in
one
of
the
mericarps.
35.
B
-D.
Fruits
with
holes
in
the
periearp
bored
by
the
adult
insects
at
the
time
of
their
escape.
x2'S.
The
maximum
(51.8
per
cent)
seed
-set
in
Anethum
is
in
the
umbels
of
the
first
order,
and
it
declines
in
the
umbels
of
higher
order.
The
low
seed
-set
is
due
to
the
presence
of
male
fl
owers,
underdeveloped
fl
owers
and
lack
of
proper
pollination
and
fertilization.
Fm.
2A
-D.
Anethum
graveolens
(de,
degenerated
embryo;
e,
embryo;
en,
endosperm;
di,
developing
insect;
n4
1
and
m
2
,
mericarps).
A.
Upper
portion
of
mericarp
(1.s.)
showing
heart
-shaped
embryo
and
an
early
stage
of
the
insect.
x
67.
B,
C.
Same,
note
the
insect
and
degenerated
embryo
at
the
micropylar
end
in
one
of
the
mericarps.
B
x
48
;
C
x
51.
D.
En-
larged
view
of
upper
portion
of
mericarp
from
C.
x
245.
SEHGAL.
Proc.
natn;
Inst.
Sci.
India,
Vol.
34,
B,
Plate
VII.
The
seeds
require
a
low
temperature
(15
to
25°
C)
for
germination.
In
the
umbellifers
investigated,
poor
germination
is
mainly
due
to
(a)
abortive
seeds
lacking
endosperm
and
embryo,
(b)
seeds
with
normal
endosperm
but
without
embryo
and
(c)
seeds
with
rudimentary,
dormant
or
defective
embryos.
C
D
E
PLATE
VII
FIG.
4A
—E.
A,
E.
Anethum
graveolens;
B.
Systole
albipennis
;
C.
Tetrastichus
;
D.
Traehyspermum,
ammi
(f,
fruit;
in,
insect).
A.
30
-day
-old
culture
of
ovary
with
partly
emerged
Systole.
x
2.6.
B,
C.
Insects
entrapped
in
culture
tubes.
B
x
22;
C
x
30.
D,
E.
Degenerated
embryos.
D
x
78;
E
x
48.
Embryolessness
in
the
seeds
of
umbellifers,
studied
from
various
parts
of
India,
is
due
to
the
infestation
by
a
phytophagus
fl
y
(Systole
albipennis)
which
lays
an
egg
(rarely
two
or
three)
in
the
maturing
fruits
in
the
vicinity
of
endosperm
or
embryo.
The
egg
develops
into
the
adult
fl
y
at
the
cost
of
embryo,
endosperm,
or
both,
and
fi
nally
it
escapes
by
boring
a
hole
in
the
SEED
-SET
AND
GERMINATION
IN
UMBELLIFERS
69
pericarp.
Sometimes,
the
Systole
may
be
parasitized
by
Liodontomerous
or
Tetrastichus.
These
parasites
lay
eggs
in
the
infested
ovaries
and
the
egg
develops
into
an
adult
at
the
cost
of
the
larvae
of
Systole.
Finally,
the
para-
sites
also
escape
by
boring
a
hole
in
the
fruit
wall.
It
may
be
pointed
out
that
though
Lygus
occurs
in
India,
there
is
no
record
to
indicate
that
it
causes
embryolessness
of
umbelliferous
seeds.
My
own
studies
and
those
of
Gupta
(1962a,
b)
show
that
embryolessness
is
due
to
the
infestation
of
ovaries
by
Systole
albipennis.
The
umbellifers
are
com-
mercially
important,
and
poor
germination
of
seeds
reduces
the
yield
of
the
crop
appreciably
causing
heavy
losses.
Further
studies
to
improve
the
seed
-
set
are
desirable.
ACKNOWLEDGEMENTS
I
am
grateful
to
the
late
Professor
P.
Maheshwari,
F.R.S.,
and
Professor
B.
M.
Johri
for
encouragement
and
advice.
Thanks
are
also
due
to
Dr.
P.
S.
Ganapathy
for
going
through
the
manuscript,
and
to
the
Indian
Council
of
Agricultural
Research,
New
Delhi,
for
fi
nancial
assistance.
REFERENCES
Beneg,
V.
(1949).
The
observation
of
the
conditions
of
blooming
of
celery.
Sb.
Gel.
Akad.
zeragd.
Vgd,
21,
54-57.
(Original
paper
in
Russian
with
English
summary).
Borthwick,
H.
A.
(1931).
Carrot
seed
germination.
Proc.
Am.
Soc.
hort.
Sci.,
28,
310-314.
Braak,
J.
P.,
and
Kho,
Y.
0.
(1958).
Some
observations
on
the
floral
biology
of
the
carrot
(Daucus
carota
L.).
Euphytica,
7,
131-139.
Flemion,
Florence
(1955).
Penetration
and
destruction
of
plant
tissues
during
feeding
by
Lygus
lineolaris.
Rep.
14th
int.
hors.
Contr.
(Netherlands),
Sec.
3C,
1003-1007.
Flemion,
Florence,
and
Henrickson,
Esther
T.
(1949).
Further
studies
on
the
occurrence
of
embryoless
seeds
and
immature
embryos
in
the
Umbelliferae.
Contr.
Boyce
Thompson
Inst.
Pl.
Res.,
15,
291-297.
Flemion,
Florence,
and
Olson,
June
(1950).
Lygus
bugs
in
relation
to
seed
production
and
occurrence
of
embryoless
seeds
in
various
umbelliferous
spices.
Contr.
Boyce
Thompson
Inst.
Pl.
Res.,
16,
39-46.
Flemion,
Florence,
and
Uhlmann,
Gloria
(1946).
Further
studies
of
embryoless
seeds
in
the
Umbelliferae.
Contr.
Boyce
Thompson
Inst.
Pl.
Res.,
14,
283-293.
Flemion,
Florence,
and
Waterbury,
Elizabeth
(1941).
Embryoless
dill
seeds.
Contr.
Boyce
Thompson
Inst.
Pl.
Res.,
12,
157-161.
Gupta,
S.
C.
(1962a).
Occurrence
of
exembryonate
seeds
in
the
Umbelliferae.
Curr.
Sci.,
31,
203-205.
(1962b).
Development
of
exembryonate
seeds
in
Foeniculum
vulgare
Mill.,
pp.
188-191.
In
Plant
Embryology
-A
Symposium,
C.S.I.R.,
New
Delhi.
(1964).
The
embryology
of
Coriandrum
sativum
L.
and
Foeniculum
vulgare
Mill.
Phytomorphology,
14,
530-547.
Harrington,
J.
F.
(1951).
Effect
of
spacing
and
size
of
root
on
carrot
yield
and
germination.
Proc.
Am.
Soc.
hors.
.Sci.,
58,
165-167.
Hicks,
G.
H.,
and
Key,
S.
(1898).
Additional
notes
on
seed
testing.
Yb.
U.S.
Dep.
Agric.,
1897,
441-452.
Hicks,
Selma
S.,
Doty,
D.
M.,
and
Quackenbush,
F.
W.
(1951).
A
germination
inhibitor
from
apple
and
celery
seeds.
Fedn
Proc.
Fedn
Am.
Socs
exp.
Biol.,
10,
196-197.
Hopkins,
Elizabeth
F.
(1928).
Further
studies
of
celery
seed
germination.
Proc.
Ass.
off.
Seed
Analysts
N.
Am.,
19
120,
69-70.
70
SEHGAL
:
SEED
-SET
AND
GERMINATION
IN
UMBLL.u.i.r
Ana
Bho,
Y.
0.,
and
Brask,
J.
P.
(1956).
Reduction
in
the
yield
and
viability
of
carrot
seed
in
relation
to
the
occurrence
of
the
plant
bug
Lygus
campestris
L.
Euphytica,
5,
146-156.
Robinson.
R.
W.
(1954).
Seed
germination
problems
in
the
Umbelliferae.
BM.
Rev.,
20,
531-
550.
Sehgal,
C.
B.
(1965).
The
embryology
of
Cuminum
oyminum
L.
and
Trachyspermum
ammi
(L.)
Sprague
(=
Carum
copticum
Clarke).
Proc.
natn.
Inat.
Sci.
India,
B
31,
175-201.
Stokes,
P.
(1953).
The
stimulation
of
growth
by
low
temperature
in
embryos
of
Heracleum
aphondyhum
L.
J.
exp.
Bot.,
4,
222-234.
Taylor,
C.
A.
(1949).
Some
factors
affecting
germination
of
celery
seed.
Pl.
Phyaiol.,
Lancaster,
24,
93-102.