Development of ovule Erythroxylum coca Lamk.

Ada
Bot. Neerl.
29
(4/5), August 1980,
Development
231-241.
p.
of
and
ovule
seed -coat of
Erythroxylum
F.D.
Hugo
Boesewinkel
de Vries
and
Laboratorium,
Plantage Middenlaan 2a,
coca
Lamk.
J. Geenen
Universiteit
van
Amsterdam
1018 DD Amsterdam
SUMMARY
The inner
and outer
integuments of Erythroxylum
integument is initially
become
mass
multiplicative
of the seed.
activity
in
the
the fibrous
and
The inner
coca
are
both
and later 3-5 cells thick. The inner
ultimately
layer
beneath the
part
exotegmen. The
is
about
20 cells
developed
embryo sac.
as
thick and
of dermal
The testa and
derivation.
integument is
thus
an endothelium.
flattened cells of the inner
and Linaceae
Erythroxylaceae
1.
3 cells
forming
the
The nucellus is
legmen are
layer contain
The outer
at first 3 cells thick to
crushed
greater part
oblong by
with the
tannin. The
of the
mitotic
exception
of
relationship between
is discussed.
INTRODUCTION
The small
family
of the
Erythroxylaceae
distributionand contains
genus
Erythroxylum
P.Br.,
whereas
Benth., Nectaropetalum Engl,
only
one or
a
few
(about
250
species.
and
The
the
other,
Pinacopodium
family
is
sp.)
Most
only woody representatives.
doubtful,
Exell &
is considered
be
to
of
chiefly
tropical
species belong
genera
to
the
Aneulophus
Mendonga
each have
closely related
to
the
Linaceae.
The first
the
family
with the
publications dealing
embryology
and seed-coat anatomy of
those of Van Tieghem (1903) and Tunmann & Jenzer
are
date are the contributions of Mauritzon
more recent
(1934),
(1910).
Narayana
Of a
(1960,
1964, 1970), Rao (1968) and Narayana & Rao (1978).
According
of
to
Netolitzky (1926), Corner
Erythroxylum
are
nucellus and thick
massive inner
inner
integument.
integument,
Davis
of the
form the
layer
mechanical
The
(1966),
seed has
developing
but the seed-coat becomes much
stages with the exception
only
(1976) and
anatropous, bitegmic and crassinucellate
dinal direction of the seed.
the ovules
with
a
initially
slender
a
very
in later
compressed
sclerotised cells of the exotegmen. These cells
of the seed-coat and
fruit is
The
a
are
one-seeded,
oriented in the
red
longitu-
drupe with
a
well-
developed endocarp.
But little
chemodiagnostic
Erythroxylum
thetic and
2.
a
coca
E.
studies
were
made on the
novogranatense
contain
family (Hegnauer 1966).
cocain,
a
powerfull
anaes-
dangerous, habit-forming drug.
materials
The
and
material
and
of
methods
Erythroxylum
coca
Lamk.
and
E.
novogranatense
(Morris)
232
F. D.
Hieron.
the
collected in the Hortus Botanicus,
was
hothouses of the
of Plant
Department
BOESEWINKEL AND
of Amsterdam and in
University
and Plant
Taxonomy
J. GEENEN
Geography,
Agricultural University, Wageningen.
Craf
Allen-Bouin mixtures
or
of standard microtome
means
used for
colour
specific
used
were
techniques
or
fixatives. Sections
as
hand. The
by
Phloroglucinol-HCl,
tests;
Sudan IV,
by
cut
were
following
stains
were
ruthenium-red
and IKI.
The SEM observations
objects
stuck
were
on
were
made with
Scotch
thin
Stereoscan mark 2a. The
Cambridge
a
copper-foil
with
adhesive
conducting
and
mounted on the specimen stub with Demetron silver conducting paint. The fixed
material
was
scanned after 3 minutes of
10 K.V.
high voltage of
3.
sputter-coating
with
gold-palladium.
A
consistently used.
was
RESULTS
Erythroxylum
in
only
and E. novogranatensehave
coca
locule
one
fully
a
ovules. Sometimes
rudimentary
The
other
locules often contain
second ovule is
present in
rudimentary
a
3-loculed syncarpous ovary with
a
ovule.
developed
one
of
the locules.
3.1.
Ovule
The
ovule
itiated
it
mal and
ontogenesis
first
primordium
begins
to
and
one-celled,
bends
down, but when the integuments
upwards
curve
it divides
I
{fig.
in
a
A).
parietal
The
cell and
cell. The megaspore tetrad is linear and the chalazal
In
one
case
2-celled
a
rather short but it
soon
archesporium
becomes
below the megaspore mother
A micellar
cap
The inner
periclinal
I
not
formed. The
layer,
A).
but also
The
outer
visions in
and does
is
a
At
an
by
never
development
a
some
layers
seems
in
delayed
rather compact, but later an
It
at
first
nucellus
the
activity
as
a
wall
complete ring
develops
the
is
in the part
(fig. IC-E, 3).
resulting
band of about three adjacent
of about three dermal cells
thick.
functional.
of cells
rows
mother
megaspore
tissue becomes about 2-3 cells thick.
high, but
the
and
but
middle
shorter
early stages (figs. IB, E).
appreciable elongation
in the
cell di-
oblique
ring wall
side. From the very
much
thick,
original
layer (fig. 1C, D).
by periclinal
raphal
remains
from
dermal cell
the i.i. is about 3 cells
divisions of the
cell divisions in the inner
also
At
in-
becomes
result of mitotic
mainly by periclinal
develop distinctly
cell
a
early developmental stage
integument (o.i.)
zone
three
parietal
in
oblique divisions
it increases in width
soon
oblong
as
cell, producing parallel
integument (i.i.) develops
and
layers (fig.
o.i.
is
observed.
was
a
one
are
hypoder-
is
archespore
is
incomplete
beginning
than the
i.i. and
The ovule is
longitudinal
the
its
initially
direction
takes place (figs. IA-E, 3).
3.2.
The
The
full-grown
gated
mature
nucellus
ovule
ovule is anatropous,
(fig. 3).
The
upper
bitegmic
portion
and crassinucellate with
of the nucellus
an
is resorbed
elon-
by
the
OVULE AND
Fig.
es
=
=
1.
SEED-COAT OF ERYTHROXYLUM
Erythroxylum
embryo
outer
sac, end
coca.
=
integument, pvs
l.s. of
developing
endosperm,ent
=
provascular
233
COCA
=
ovules. In all
figures:
endothelium, nuc
strand.
=
nucellus'.
ii
=
inner
integument, oi
234
F.
Fig.
2.
D.
BOESEWINKEL AND
Erythroxylum
coca,
t.s.
of
J.
GEENEN
developing
seed-coats.
A: part
of
developing
fertilisation
B: developing
seed
shortly
(corresponding
seed-coat
after
with
fig. 4A);
(corresponding with
fig. 4B).
C:
seed-coat
shortly
maturation.
before its
complete
OVULE AND SEED-COAT OF ERYTHROXYLUM
Fig.
3.
Development
embryo
of
anatropy
The i.i.
sac.
in
the
vacuolated. The
distinctly developed
at
contains tannin. The
circular
an
3.3.
the
outer
raphal
micropyle
triangular
or
two
Seed
3.3.1.
A,
and
Shape
4.
layer
C; t.s. of
of
one
layers
thick. The
side and 3-4 cell
is formed
only by
layer
are
cytoplasm.
isodiametric
The o.i.
thick. The
layers
the i.i. and in
developed
cross
both
only slightly papillose.
by
is
outer
not
layer
section has
dermal and
Funicle and
raphe
seed.
development
developing
ovule
coca.
developing
ripe
is rich in
form. An obturator is
seed-coat
of the
Erythroxylum
B: t.s.
5-6 cell
separate vascular bundles each surrounded by tannin deposits.
Although only
Fig.
coca.
endothelium and consists of radially oriented
subdermal divisions. The cells become
contain
Erythroxylum
and tannin-rich cells. The cells of the middle
and strongly
a
ovule of
is very massive and has become
inner layer is differentiated into
cytoplasm-
235
COCA
seed
fruits
seed
develops
into
development.
(with seeds);
a
seed, the other
two
locules often each
236
F.
contain
a
develop
further for
retarded ovule without
coats never
become
with the ovules.
them
a
layer
of
GEENEN
are
may
seed-coat. But these seed-
a
crushed in later stages
together
The locules of the unfertilised seeds remain small, but around
endocarp fully develops.
longitudinally oriented
two
longitudinal
the fruit wall of
take
These
locules offer
two
place.
It is
The
3.3.2.
The
which the
some
resistance
is
micropyle
to
gradually
contain
large pit
but elsewhere
slimy
seed
(Jigs. 2A, B).
fields. In the
The
The
3.4.
Fig.
A:
5. SEM
seed
Erythroxylum
coca,
C: E. novogranatense,
D: E.
a
coca,
novogranatense.
coca,
t.s.
more or
from
and
adjacent
adjacent
are
the
to
outer
layer
poor
and resorbed. The
longitudinal
pluri-layered
the o.i. is about 4-5
or
3 innermost
temporarily
are
cells.
B, 4B). The
by
in starch and their walls
cells,
layers
stretched
are
in the
direction of the seed
longitudinal
raphe
,
the endothelium.
to
becomes
raphe
become
less oriented in the
2A
and stretch in the
layer locally
at
tangentially
parenchymatic
becoming compressed
This
well-developed
seed and
and
(A)
cross
seed-coat
seed-coat
endocarp
standard
sections
(about
intact seed-coat
of seed-coat
F: E.
novogranatense,
centri-
place
(endothelium)
(figs.
amphicribral (fig. 2A).
X
is present.
At
X
inside of the
and fruit
(about
X
4);
100);
not in
close contact with the
slightly damaged,
(about
exotegmen
the
photograph.
of seed
with
endocarp (about
impressions
of
1000);
E: E.
place
vigourously
of the i.i.
3 cells thick. The cells of the 2
photomicrographs
Erylhroxylum
forms
seed
mature
Around the
in the cells
vascular strands in the
two
layer
cytoplasm-rich
are
zone
isodiametric. The cells of the
(fig. 2B).
early stages
which later become
about 20 cells thick
The cellsof the o.i.
(fig. 2B).
radial directionand
thick and in
endosperm develops
(fig. 2A)
starts
of the i.i.
mostly only
to
before
layer
divisions
periclinal
The
cells
up
of the middle layer
direction of the
As
pronounced (fig. 4B).
is poor in starch and consists of
layer
The cell walls first become
outer
of the i.i.
layer
but later wall formation takes
crushed. The inner
ridges this layer becomes
cells of the
most
attributable
partly
Rao (1968) wall formation takes also
radially elongated
flattened.The middle
disintegration
periclinal divisions
the i.i.
progressively replaces
At the
are
(fig. 2A, 4A, B).
initially nuclear,
The seed-coat is
many
ridges
divisions in the middle
very
two
the other side of the seed
the result of the presence in
in which
bundles run is
raphe
towards the chalaza.
first consists of
as
at
of the seed-coat
Development
endosperm
periclinal
divisions the i.i. is
petally (fig. 2B). According
the
of
amount
numerous
case
zones
that the four grooves and
of the bulk of the seed
most
but in this
develop
lengthwise running
probable
ridge through
result of the
grooves {figs. 4B, 5A). Also
grooves
two
differences in the
to
B:
J.
the seed in later stages of maturation and this results in the formation of
to
a
form
even start to
differentiated and
fully
BOESEWINKEL AND
After fertilisation these ovules
embryo.
time and
some
D.
500);
cells seen from above
(about
X
1000).
X
250);
endocarp layer (about
X
OVULE AND
SEED-COAT
OF ERYTHROXYLUM
COCA
237
238
F. D. BOESEWINKEL
endocarp
against
latter
the
a
cuticle
easily
can
seed-coat,
all
layers
From the
cross
1. The
B:
C,
6.
even
of the seed-coat
to
the
in
Side wall
cell
layer
(Jig. 5F).
the inside the
D: Thick-walled
novogranatense,
of exotegmen
raphe
adheres
the
can
GEENEN
tightly pressed
the seed-coat the
endocarp. Varying bits
be
off,
torn
With the
crushed
is
to
J.
exception
or
following layers
so
that in
of
such
of the exoteg-
resorbed.
can
be
distinguished
in
(fig. 20) :
outer
in the seed. When
of exotegmen
o.i.,
ultimately
are
derived from the
Erythroxylum
Rents
peeling of
the whole
layer
cuticle. The crushed cells of this
lengthwise
is present which
endocarp strongly
damaged by
locally
periphery
layer
oriented
A;
become
and
section of the seed
spicuous
Fig.
with Sudan IV
the exotegmen becomes visible
places
men
reacting
the seed-coat. Because the
AND
cell
cells
seen
SEM
(about
x
covered
this
layer
photomicrographs.
x
500
1000);
and
(about
x
with
contain tannin and
undamaged
from the inside
(about
of the o.i.,
layer
x
2500)
1000, respectively).
are
an
incon-
in
general
is rather smooth and
OVULE AND SEED-COAT OF ERYTHROXYLUM
shows
locally
longitudinal
2.
The
The exotegmen,
(Jigs. 5F, 6A).
longitudinal
the
of the
layers
the
forming
strongly
elements
The wall
developing endosperm
flattenedand
thick
cuticle which
This
(Jig. 5E).
(figs. 6C, D).
lipids.
The
strongly
hypostase
is there
nor
The
straight embryo
Erythroxylum
nearly
are
is
replaced
as
strongly
elements.
layers
is
thick and consists of cells
separated
from the seed-coat
with Sudan IV.
and
pitted
non-lignified
pectinous
cells
and the
is
mesocarp. There
parenchymatous
measures
about 10 mm
x
mostly rough by damage
has
planoconvex
5
cotyledons
mm
its
to
(fig. 5A)
outer
and
a
and is
layer (see
short radicle.
varies.
cotyledons
and E.
resemble each other
novogranatense
very
coca
no
the chalaza.
at
closely
in
structure.
Erythroxylaceae
related
closely
bryological
are
to
anatomical features
by
the
almost
(Heimsch
1942 and
(Narayana
treated as separate families. Only
Hallier
two
family Linaceae,
(1923). According
families
and seed
unambiguously
development
of
to
a
for
of the
vestigated
one
baceous species
probably
not
Erythroxylum
A
there
is
derived within the
of its
One
considered
Chalk
these
1950) and
taxa
no
Hooker
characters
comparison
that of the
these
to
(1862)
and
few
distinguish
Linaceae is
more
1980).
the
em-
as
a
and
the
between the ovule
characteristics in
of the
Linaceae,
to
usually
are
classify the Erythroxylaceae
are
with
difficult
represen-
intensively
in-
However this her-
ovule
morphology
is
Nevertheless the ovule and the seed of
and those of Linum show the
principally bitegmic
1978)
(Boesewinkel
family.
opinion
Bentham &
concerning
is Linum usitatissimum
representative
Rao
another. A
very scanty.
of
of differences between their
Metcalfe &
&
example
Erythroxylum
Linaceae is
taxa
consensus
few authors
Hallier,
from
because the relevant information
tatives
general
Linaceae but because
characteristics
tribe of the
1.
in
Especially
DISCUSSION
The
be
seed
but
of orientation of the
plane
The
the seed
(Jig. 6B).
original bulky layer
endosperm
reacts
corky plug
undamaged
ovule and seed
4.
a
light brown, grooved
smooth when
The
in
This type of cell may also be found in the transitional zone between
lignified endocarp
above).
reticulate.
are
endothelium, appearing
tannin-containing
the sclerotised
The
protrude
embryo (figs. 4B, C).
of thick-walled,
raphe consists
The
the
seed-coat.
lengthwise
of the i.i. of which the cells
layer
and the
of the
layer
show ramifications
thickenings
which is about 20 cell
endosperm layer,
rich in starch and poor in
a
which sometimes
oriented
of these cells
thickenings
sections the cell wall
crushed and resorbed
tangentially
by
o.i.,
are
5. The inner layer of the i.i. derived from the
6. The
to
running perpendicular
mechanical
only
lignified
derived from the middle
layer
completely
by
cells
endocarp
(figs. 5B, D).
exotegmen.
sclerotised and
4. The
of the
imprints
three crushed inner
two or
into the
3.
the
axis of the seed
239
COCA
following striking
and crassinucellate ovule
(only
similarities:
some
species
of the
240
F. D.
Linaceae show
tendency
a
towards
tenuinucelly
2. The slender nucellus which becomes resorbed
3.
dermal
Exclusively
of the
at an
BOESEWINKEL AND
J.
GEENEN
ovules).
early stage.
integuments.
4. The
clearly differentiated raphe
5. The
multiplicative
bundle.
i.i.
6. The differentiationof the inner
of the i.i. into
layer
endothelium.
an
7. The fibrous exotegmen in the seed-coat.
8. The inner
9. The
of the i.i. which
layer
initially
nuclear
10. The presence of
In
the
a
conspicuous
minor
following
into
develops
a
pigment-containing layer.
endosperm.
cuticle between the seed-coat and
characters
the
ovule
and
seed
of
endosperm.
Erythroxylum
differ from those of Linum:
1. In
Erythroxylum
Linum it is
2.
In
the i.i. is
Erythroxylum
ticulation is
protective
the
possibly
3. In
function of the seed-coat
Erythroxylum
Rao (1965) this has
has
exotegmen
reticulate wall
reduction associated with the
a
of the exotegmen cells
ings
from its initiationonward, whereas in
three-layered
two-layered.
two
are
the
to
shifting
of the
re-
originally
In Linum the wall thicken-
homogeneous.
vascular bundles
something
endocarp.
This
thickenings.
run
the
through
raphe. According
to
do with the loss of function of two of the locules
to
and with the reduction in the number of ovules.
4. In Erythroxylum
only
seed
one
develops
per
fruit, and an appreciable
number
in Linum.
The
to
Erythroxylum
that in Linum
the
three
originally
ovule of
layered
are
(not necessarily
development of only
coat
in
taxa as
and seed-coat
to a more
anatomy
with the
in
his
taxonomic
order Linales.
position
of the
of ovules and seed-coat
Malpighiales
is
one
could
definite conclusions
can
as to
them
places
There is
development
limited,
crassinucellate
query
thus
the
and
compared
the
place
1931;
in
and
Since
regards
as
our
Geraniales,
1951).
Cronquist
the
knowledge
Linales and
information is needed before
position of the
of
two
Erythroxylaceae
disagreement
structure
seed-
of the
Lawrence
Malpighiales
much
however,
viewpoint
segregation
Erythroxylaceae.
more
the taxonomic
in
as
compressed
derived condition. From the
Linaceae and
still rather
always
condition
On the other hand,
Linaceae).
in the Geraniales (Schulz
Linaceae,
However, Hutchinson (1973)
laceae
primitive
members of different families. Most authors
together
(1968)
in all
nucellus and
more
viable seed per fruit and the much
one
Erythroxylum point
embryology
i.i., bulky
indicative of a
Linaceae and
more
Erythroxy-
be drawn.
ACKNOWLEDGEMENTS
The authors whish to thank
interest,
encouragement
Dr. F. Bouman for useful discussions
and critical
perusal
of the
and Prof. A. D. J. Meeuse
original English
draft.
for his
OVULE AND SEED-COAT
OF ERYTHROXYLUM
241
COCA
REFERENCES
G. & J. D. Hooker
Bentham,
F. D.
Boesewinkel,
Neerl.
Corner,
29:
Davis,
A.
Hallier,
H.
tralbl.
zur
Kenntnis
(1966)! Chemotaxonomie
of Wettstein with reference
Hutchinson,
J.
(1973):
G, H. M,
C. R.
—
—
Zur
(1960):
der
Pflanzen
of the
Boston.
York. London.
(D.C. 1819)
IV.
Dumort.
Sydney.
Beihefte
94-99.
Erythroxylaceae:
Bot.
Cen-
grouping.
Bull. Indian
(1950);
a
few
The anatomy
of
322-224.
comparative
floral
on
ot
28:
New
51:
270-275.
Curr. Sci. 33: 441-442.
of
angiosperms,
Delhi:
41.
Humiriaceae, Linaceaeand Erythroxylaceae
and
York.
84-102.
I. Oxford.
Acad. Sci.
comparative embryology
Academy
morphology
Indian
London.
554-555.
Svensk Bot. Tidskr.
Proc.
Erythroxylum.
Symposium
Natn. Science
I.
and “Terebin-
Lilloa 8: 83-198.
of the dicotyledons
Erythroxylaceae
species
in:
Gruinales.
Basel, Stuttgart.
in the “Gruinales”
secondary xylem
to taxonomic
Rao(1978): Systematic position
of their
Linaceen
Embryologieeiniger
(1970): Erythroxylaceae,
&D.
der
angwsperms. New
families offlowering plants. Erythroxylaceae:
Studies in
(1964): Embryology of
133-135.
—
The
& L. Chalk
L. L.
Narayana,
Cambridge.
(1951): Taxonomy of vascular plants. Erythroxylaceae:
Mauritzon, J. (1934):
Metcalfe,
L. Acla Bot.
1-178.
R.
Lawrence,
usitatissimum
classification offloweringplants.
Heimsch, C. (1942):Comparative anatomy
thales”
2 vols.
of Dicotyledons.
The evolution and
(1923): Beitrage
39;
Hegnauer,
The seeds
(1976):
(1968);
(1966): Systematic embryology of the
G. L.
244. London.
(1). Erythroxyleae:
of ovule and testa of Linum
17-32.
J. H.
E.
Cronquist,
Genera Plantarum 1
(1862):
(1980): Development
embryology
-
A discussion.
J. Indian
in the
light
Bot. Soc.
57:
258-266.
Netolitzky,
F.
(1926):
Anatomie der
Pflanzenanatomie. Band X, 4,
Rao,
—
D.
(1965):
(1968):
Floral
anatomy
A contribution
to the
Angiospermen-Samen.In:
K. Linsbauei
(ed.),
Handbuch
der
Berlin.
of
Erythroxylaceae.
embryology
Proc.
Natn. Acad.
Sci.,
India 35B:
of Erythroxylaceae. Proc. Natn. Acad.
Sci.,
156-162.
India
38B:
53-65.
Schulz,
O. E.
2 Aufl. Bd.
Tieghem, Ph.
(1931):Erythroxylaceae.
19a:
van
In: A.
Engler&K. Prantl:
Dienatiirlichen
PJlanzenfamilien.
130-143.
(1903):
Structure et affmités des
Erythroxylacées.
Bull. Mus. Hist. Nat.
Paris,
9:
287-295.
Tunmann, O.
& R, Jenzer
Erythroxylon
coca
(1910):
Zur Anatomie der Blüten
Lam. Arch. d.
Pharmaz.,
von
248: 514-519.
Pilocarpus pennatifoliusLem.
und