Annals of RSCB
Vol. XVIII, Issue 1/2013
ANATOMY OF GINKGO BILOBA L. LEAF (GINKGOACEAE)
Rodica Bercu
FACULTY OF NATURAL AND AGRICULTURAL SCIENCES,”OVIDIUS”
UNIVERSITY, CONSTANTZA
Summary
The paper presents a detailed anatomical description of Ginkgo biloba L. leaf. It was
observed that the petiole has a one-layered epidermis, covered by cuticle, a differentiated
cortex and a stele represented by four collateral bundles alternating with large secretive
ducts. The leaves are bifacial and hypostomatic (sunken stomata) with a homogenous
mesophyll. The mesophyll poseesses tanniferous and oxaliferous cells.
Key words: anatomical study, petiole, lamina, Ginkgo biloba
sarcotesta) is light yellow-brown, soft, and
fruit-like (Raven et al., 2005). It is
attractive in appearance, but contains
butyric acid (also known as butanoic acid)
and smells like rancid butter or vomit when
fallen (Plotnik, 2000).
The species has fan-shaped petiolate
falling leaves with veins radiating out into
the leaf blade, sometimes bifurcating, but
never anastomosing to form a network (Fig.
1) (Dallimore, 1967).
Introduction
Because of its unique position
botanists found it difficult to classify the
Ginkgo. It has been placed in a separate
group in recent years, the division (phylum)
Ginlgophyta,
order
Ginkgoales,
Ginkgoaceae family. The only living
representative of the order Ginkgoales is the
widely-cultivated Chinese Ginkgo biloba L.
has an evolutionary lineage that dates back
to the Lower Jurassic, about 190 million
years ago (Del Tredici, 1989; Taylor &
Edith, 1993).
The ancient Ginkgo biloba tree (syn.
Salisburia adiantifolia Smith, Pterophyllus
salisburiensis, Nelson) is known as
maidenhair tree, Ginkgo tree or tree of
pagodas. It is much appreciated for
hundreds of years in his home country
China where growing spontaneously. The
plant has been expanding in other countries
(including Europe), both for its ornamental
appearance as well as for medical purposes.
(Marin, 2000; Zaharia, 1998; Web 2).
Ginkgo biloba is a deoecious tree up
to height of 20–35 m high, with separate
sexes, some trees being female and others
being male. Male plants produce small
pollen cones with sporophylls, each bearing
two spirally arranged microsporangia
around a central axis. Female plants do not
produce cones. Two ovules are formed at
the end of a stalk, and after pollination, one
or both develop into seeds. The seed is 1.5–
2 cm long. Its fleshy outer layer (the
Fig. 1. Ginkgo niloba L. leaves
In literature there are little
information regarding the vegetative organs
anatomy of Ginkgo biloba (Batanouny,
1992; Dallimore, 1967; Raven et al., 2005)
and those of leaf anatomy almost lack.
Mostly recent studies are focused on
biometrical and physiological studies
concerning Ginkgo biloba leaves (Leigh et
al., 2011). It was described the
ultrastructure of stomatal development in
G. biloba leaf, as well (Rudall et al., 2012).
In the Romanian literature were few
relative recent studies concerning Ginkgo
biloba leaf anatomy belonging to Toma &
Rugina (1998) and Stan & Simeanu (2008).
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Vol. XVIII, Issue 1/2013
The purpose of this paper is to
highlight the features of leaf anatomy of
Ginko biloba and to contribute with more
information to a better knowledge
concerning this species structure.
protected, to the exterior by a layer of
sclerenchymatous sheath (Fig. 2, A, B).
The vascular system of the veins is
represented by open collateral bundles
surrounded by one-layered endodermis with
slightly lignified walls. In our findings,
such as Toma & Rugina (1998) reported,
bellow the endodermis is a layer of
parenchyma cells with pericycle value. The
pericycle presence was not reported by Stan
& Simeanu (2008). The xylem vessels are
in a radial arrangement into a cellulosic
parenchyma. Around the conductive tissues
a diffusion tissue occurs (Fig. 2, C).
Cross section of the lamina exhibits
an upper epidermis with more or less
rectangular and thick-walled cells. The
lower epidermis has smaller cells with
slightly radial elongated walls. The lower
epidermal cells are broken by the presence
of stomata – hypostomatic lamina – with
evidently substomatal cavities.
The mesophyll is multi-layered
(more than 10 layers of cells) with large and
irregular in shape cells. In the mesophyll
are embedded a number of vascular bundles
of the veins alternating with large resin
ducts (Fig. 3, A). The resin ducts have the
same conformation with those of the petiole
but are larger in size (Fig. 3, B).
Anatomically, the two vascular bundles are
the same as those of the petiole, but in a
foliar arrangement of the conductive
tissues. The vascular bundles are
surrounded by a parenchymatous sheath
(Fig. 3, C). Some of the sheath and
mesophyll cells possess tannin or calcium
oxalate crystals, such as Toma & Rugina
reported for the leaf lamina of G. biloba
and no mentioned by Stan & Simeanu
(2008).
Our findings, such as those of Stan
& Simeanu (2008), disclose that the nonglandular trichomes are absent on the upper
epidermis.
Material and Methods
The leaves were collected from Blaj
Botanical Garden in august 2011. Small
pieces of leaves were fixed in FAA
(formalin: glacial acetic acid: alcohol
5:5:90). Cross sections of the vegetative
organs were performed by the free hand
made technique (Bercu & Jianu, 2003). The
samples were stained with alum-carmine
and iodine green. Anatomical observations
and micrographs were performed with a
BIOROM–T bright field microscope,
equipped with a TOPICA 6001A video
camera.
Results and Discussion
Cross section of the petiole reveals a
hemispheric shape. The one-layered
epidermis is made up of rectangular and
slightly elongated cells tangentially. The
external walls of the epidermal cells are
covered by a thick cuticle. Toma & Rugina
(1998) studied the petiole anatomy and
suggested the presence of rare nonglandular trichomes in adaxial position.
Here and there, the epidermis continuity is
interrupted by the presence of few
engrossed stomata. In hypodermal position
is an external sclerenchymatous area
represented by two discontinuous layers of
sclerenchyma cells. In our findings and
Stan & Simeanu (2008), no hypodermal
collenchyma cells were found such as Toma
& Rugina (1998) reported for G. biloba
petiole. The rest of the cortex is a multilayered inner area with parenchymatous
cells and intercellular spaces among them.
In the inner cortex seven resin ducts are
present. The secretive thin-walled cells are
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Annals of RSCB
Vol. XVIII, Issue 1/2013
A
B
C
Fig. 2. Cross section of the petiole. Ansamble (A, x 50). Portion with resin duct (B, x 156). Petiole
vascular bundles (C, x 156): c- cortex, dt- diffusion tissue, e- epidermis, ed- endodermis, ic- inner
cortex, ph- phloem, rd- resin duct, s- stoma, scl- sclerenchyma, vb- vascular bundle, x- xylem.
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Annals of RSCB
Vol. XVIII, Issue 1/2013
A
B
C
Fig. 3. Cross section of the lamina. Portion with mesophyll and resin duct (A, x 100). A resin duct –
detail (B, x 235). A vascular bundle (C, x 235): d- druse, ed- endodermis, le- lower epidermis, mmesophyll, ph- phloem, rd- resin duct, s- stoma, tc- taniniferous cell, vb- vascular bundle x- xylem
inner one. The vascular system of the veins
is represented by open collateral bundles
cortex. The vascular system is surrounded
by an endodermis and a pericycle. Resin
Conclusions
The petiole in cross section exhibits
a one-layered epidermis and a differentiate
cortex in two areas and resin ducts in the
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Annals of RSCB
Vol. XVIII, Issue 1/2013
Toma C., Rugina, R.: Anatomia plantelor
medicinale.Atlas. Editura Academiei Romane,
Bucharest, 1998.
Zaharia, D.: Arboricultură ornamentală. Editura
Triade, Cluj-Napoca, 1998
ducts are present and the secretive cells are
protected by a sclerencyma sheath.
The leaf lamina is bifacial and
hypostomatic
with
a
homogenous
mesophyll. The vascular bundles of the
veins alternate with large resin ducts.
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