Anatomical features of three perennial swampy plants of Poaceae, grown on the water stream banks in Nile Delta, Egypt

Abstract

The anatomical structure of plants is largely varied according to genetics as well as the environmental conditions. The present study aims to describe the anatomical features of three species of family Poaceae growing naturally in canal bank habitat namely: Arundo donax, Pennisetum setaceum and Saccharum spontaneum. These plants are referred as medicinal, grazing or fiber producing plants. Samples were obtained from the canal banks in Nile delta of Egypt. The samples were fixed in formalin-aceto-alcohol and cross sections were prepared, examined using full automatic Olympus microscope and photographed at different power. In the present study, regarding leaves, the general appearance of the leaves sections showed either flat or V-shaped blade. The leaf blades of the three plants show a typical monocot organization. The mesophyll cells showed no distinct differentiation into palisade or spongy tissue. In P. setaceum and S. spontaneum, the leaves have distinct bulliform cells which enable the leaf to fold or roll. The vascular bundles of leaves are collateral, closed, numerous and diffuse in distribution. The vascular bundles are larger in size and surrounded by a sheath of fibers. However, the cross-section of the stem is more or less circular. Ground tissue is parenchymatous and not differentiated into cortex and pith in P. setaceum and S. spontaneum, while A. donax has large hollow pith. The bundles are collateral and are usually surrounded by a sclerenchymatous sheath.

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Journal of Medicinal Botany 2017, 1: 58-64
doi: 10.25081/jmb.2017.v1.863
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Short Communication
Anatomical features of three perennial swampy plants
of Poaceae, grown on the water stream banks in Nile
Delta, Egypt
Ahmed M. Abd El-Gawad*, Yasser A. El-Amier
Botany Department, Faculty of Science, Mansoura University, Mansoura 35516, Egypt
Abstract
The anatomical structure of plants is largely varied according to genetics as well as
the environmental conditions. The present study aims to describe the anatomical
features of three species of family Poaceae growing naturally in canal bank habitat
namely: Arundo donax, Pennisetum setaceum and Saccharum spontaneum. These plants are
referred as medicinal, grazing or fiber producing plants. Samples were obtained from
the canal banks in Nile delta of Egypt. The samples were fixed in formalin-aceto-
alcohol and cross sections were prepared, examined using full automatic Olympus
microscope and photographed at different power. In the present study, regarding
leaves, the general appearance of the leaves sections showed either flat or V-shaped
blade. The leaf blades of the three plants show a typical monocot organization. The
mesophyll cells showed no distinct differentiation into palisade or spongy tissue. In
P. setaceum and S. spontaneum, the leaves have distinct bulliform cells which enable the
leaf to fold or roll. The vascular bundles of leaves are collateral, closed, numerous
and diffuse in distribution. The vascular bundles are larger in size and surrounded by
a sheath of fibers. However, the cross-section of the stem is more or less circular.
Ground tissue is parenchymatous and not differentiated into cortex and pith in P.
setaceum and S. spontaneum, while A. donax has large hollow pith. The bundles are
collateral and are usually surrounded by a sclerenchymatous sheath.
Key words:
Grasses, anatomy, swampy habitat, water streams
Received:
18 September 2017
Accepted:
25 December 2017
Published:
31 December 2017
*Corresponding Author:
Ahmed M. Abd El-Gawad
Botany Department,
Faculty of Science,
Mansoura University,
Mansoura 35516, Egypt
Email:
dgawad84@
mans.edu.eg /
dgawad84@
yahoo.com
Citation:
Abd El-Gawad, A. M., Y.
A. El-Amier. (2017).
Anatomical features of
three perennial swampy
plants of Poaceae, grown
on the water stream banks
in Nile Delta, Egypt.
Journal of Medicinal
Botany, 1, 58-64. doi:
10.25081/jmb.2017.v1.863
Introduction
Plant anatomical structure of the plants is
mainly influenced by the genetics or the
environmental factors (Sattler and Rutishauser,
1997; Meng and Mao, 2013). Therefore, the
anatomical feature gives an indication of the
phylogeny as well as the habitat features and/or
structure (Cai and Guo, 1995; Liu, 2006).
Poaceae (Gramineae family) is
monocotyledonous flowering plants with around
780 genera and around 12,000 species. Grasses
have usually hollow stems and leaf is the blade.
Grass leaves are narrow alternate leaves borne
singly at the nodes and the lower part of each
leaf encloses the stem, forming a leaf-sheath
(Christenhusz & Byng, 2016). After the other big
families, Poaceae are the fifth-largest plant family
(Byng, 2014).
The grass family is of particular interest to
humans. Many species of grasses are most
economically important plant family in human
life (Cope and Gray, 2009; Kellogg, 2001). The
grass family is highly economically exploited
(Christenhusz & Byng, 2016). In addition,
grasses family is ecological dominants, which
currently comprise approximately 15% of

A. Muhammad and A. K. Bashir
59
monocots species diversity of the earth's land
surface (Clark, 2004).
Structurally, in grasses some of the species,
there are formation of tube like structures by the
leaves during water stress. Several terrestrial plant
species of family Poaceae were studied from the
anatomical point of view (Kellogg, 2015; Dogan,
1985, 1997; Dogan and Tosunoglu, 1992;
Panizzo et al., 2017). However, little studies dealt
with the anatomy of swampy grasses. Therefore,
the present investigation contributes to the
anatomical features of three species of family
Poaceae growing naturally in canal bank habitat
namely: Arundo donax, Pennisetum setaceum and
Saccharum spontaneum.
Materials and methods
Plant specimen's collection and preparation
Arundo donax Pennisetum setaceum and
Saccharum spontaneum samples were collected from
its habitat on the border of water streams within
the Nile delta (see the location data Table 1). The
samples were identified following Boulos (2005).
About 50 mm specimen of fresh leaves and
stems were taken from the healthy plants and
directly placed in vials containing a fixative
(Formalin-Aceto-Alcohol, 10:5:85, v\v).
Anatomical study
We followed the methods designed by
Jensen (1962) and Peacock and Bradbury (1973)
to investigate the anatomical characters of the
plant samples.
Dehydration and infiltration of plant samples
The collected specimens were dehydrated
using various concentrations (50, 70, 85 and
95%) of tertiary butyl alcohol (TBA) and the
tissues were allowed to remain in each change
for 3 h. and finally kept overnight in absolute
TBA to be completely dehydration.
The dehydrated samples were carefully
infiltrated with paraffin wax, where soft paraffin
wax was infiltrated into the samples, followed by
melted hard paraffin wax and heated in an oven
at 60ºC for 48 hrs. and let to complete
solidification. The specimens were mounted into
the middle of a block of melted paraplast wax, let
to cool in order for complete solidification, and
stored in a refrigerator.
Sectioning and photographing of plant
samples
The Sectioning and photographing of plant
samples were done by following Esau (1977) and
Fahn (1982) standard methods and as described
previously (El-Amier and El-Gawad, 2017). Ideal
sections were examined using Olympus
microscope and different pictures of various
plant organs were taken and described.
Results and discussion
Salient ecological features of studied grasses
(A. donax, P. setaceum and S. spontaneum) in the
present study are shown in (Table 1). These
species are naturally growing in different habitats
of the Nile Delta including high ways, fields of
orchards, canals, drains, abandoned fields and
lakes. Moreover, the anatomical investigation of
these species has been described in the present
study as following:
Table 1. Salient ecological features of studied grasses.
Scientific name
Vernacular name
Life form
Chorotype
Habitat
Location data
Arundo donax L.
Ghaab
G, He
Cult.& Nat.
Rw, Hw, Or, Ca
30°47′25.6″N
31°15′36″E
Pennisetum setaceum (Forssk.) Chiov.
Sabat, Hadaa
H
ME+PAL
Ca, Or
31°07′05.2″N
31°51′56.5″E
Saccharum spontaneum L.
Heesh
G, He
ME+PAL
Rw, Hw, Af, Ca,
Dr, La
31°06′41.7″N
31°39′16.9″E
G: Geophytes, He: Helophytes, H: Hemicryptophytes, ME: Mediterranean, PAL: Palaeotropical, Rw: Railways, Hw: High
ways, Or: Fields of orchards, Ca: Canals, Dr: Drains, Af: Abandoned fields, La: Lake.

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Arundo donax
The outline of the stem is more or less
circular as well as has wide hollow pith (Fig. 1).
There are continuous cylinders of sclerenchyma
cells close to the periphery. The outer smaller
vascular bundles are embedded in this
sclerenchyma. Widely spaced vascular bundles of
closed type are scattered throughout the cross-
section of the stem and surrounded by a
sclerenchymatous sheath. In this context, the
good reeds have a smaller size of parenchyma
cells in the cortex (Veselack, 1979), however, this
has not been confirmed in the present
investigation. The stiffness of the A. donax wood
was referred to the high amount of fiber in the
inner cortex (Spatz et al., 1997). This result is in
harmony with other related studies
(Giełwanowska et al., 2005; Guo and Miao, 2010;
Kolesik et al., 1998). Moreover, the anatomical
characteristics of A. donax showed a high content
of fibers and give a prediction of the potential
use of this crop for fiber production (Shatalov
and Pereira, 2005).
Fig 1. Cross sections of Arundo donax L. stem and leaf. A: stem, B: magnified part of stem, C: whole leaf, D: magnified part of
leaf, BS: bundle sheath, EP: epidermis, MC: mesophyll cell, MX: metaxylem, PC: parenchyma cells, PH: phloem, PX:
protoxylem, VB: vascular bundle and XC: xylem cavity.

A. Muhammad and A. K. Bashir
61
Arundo donax leaf blades cross sections show
a typical monocot organization. The leaf is an
example of the isobilateral mesophyll with
palisade parenchyma on both sides of the adaxial
and abaxile side (Fig. 1). The isobilateral leaf of
A. donax is thick and has palisade cells with large
lacunae and alternate with a region of spongy
parenchyma (Fig. 1). In the middle portion, there
is a large vascular bundle covered by two bundles
sheaths, an inner one called the mestome sheath
which have thick-walled cells. In mestome sheath
there is an outer sheath larger thin-walled cells
which are surrounded by mesophyll cells, which
is typical Kranz anatomy structure (Esau, 1997).
Pennisetum setaceum
The stem of P. setaceum is more or less
circular (Fig. 2). The epidermal patterns attained
a high degree of specialization and differentiation
in the family Poaceae (Raju et al., 1986). There
are continuous cylinders of sclerenchyma below
the epidermis. The outer smaller vascular
bundles are embedded in this sclerenchyma.
Fiber strands occur between the small bundles
and the epidermis and strands of chlorenchyma
alternate with the fiber strands (Fig. 2). Widely
spaced vascular bundles of closed type are
scattered throughout the cross-section of the
stem. The bundles are collateral and are usually
surrounded by a sclerenchymatous sheath.
Fig. 2. Cross sections of Pennisetum setaceum (Forssk.) Chiov. stem and leaf. A: stem, B: magnified part of stem, C: whole leaf,
D: magnified part of leaf, BS: bundle sheath, EP: epidermis, FI: fibres, MX: metaxylem, PC: parenchyma cells, PH: phloem,
VB: vascular bundle and XC: xylem cavity.

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Lamina of P. setaceum is wide as well as thick.
The adaxial surface is supported by a wide and
thin plate of hypodermal sclerenchyma (Fig. 2).
P. setaceum leaves have developed sclerenchyma
commonly fibers appear in longitudinal plates
extending from the large vascular bundle to the
epidermis (Fig. 2). The mesophyll of P. setaceum
showed no distinct differentiation into palisade
and spongy parenchyma. Vascular bundles are of
different sizes alternate with one another and
surrounded by bundle sheath. The middle
bundles along the lower epidermis may be the
largest or the median part of the blade is
thickened on the adaxial side represent the
typical monocot type. However, most vascular
bundles are small, crowded and angular. Metcalfe
(1960) observed that the leaf anatomical
characters showed considerable variation in the
family Poaceae.
Fig. 3. Cross sections of Saccharum spontaneum L. stem and leaf. A: stem, B: magnified part of stem, C: whole leaf, D: enlarged
part of leaf, BS: bundle sheath, EP: epidermis, FI: fibres, HC: hing cells, MX: metaxylem, PC: parenchyma cells, PH: phloem,
PX: protoxylem, VB: vascular bundle and XC: xylem cavity.

A. Muhammad and A. K. Bashir
63
Saccharum spontaneum
The cross-section of the S. spontaneum stem is
more or less circular (Fig. 3). There are
continuous cylinders of sclerenchyma close to
the periphery. S. spontaneum contained high fiber
content, where this is in harmony with other
species (Silveira et al., 2016). Ground Tissue is
parenchymatous without the demarcation cortex
and pith. The outer cells are smaller and angular
with thick walls (figure 3).
In middle portion, the cells are larger with
wavy structure. Moreover, the epidermis is
uniseriate and continuous. The epidermal cells of
the leaf show cell contents. The cells in the
region of hypodermal are uniform with thin
walls. Enlarged epidermal cells with thin
anticlinal walls, referred to as bulliform cells, and
are often described as cells participating in
leaves. The bulliform cells become flaccid
enabling the leaf to fold or to roll (Wang, 2005).
In this context, bulliform cells are commonly
found in various plant families included in
Poaceae, Cyperaceae, and Juncaceae (Grigore
and Toma, 2017).
There are many un evenly arranged vascular
bundles with varying size and shape. In outer
portion they are more or less circular in shape,
where they are collateral and closed. They have
two narrow metaxylem elements and small
protoxylem elements. The vascular bundle is
surrounded by a sheath of fibers. However,
central vascular bundles are larger in size, have
two metaxylem elements, one or two intact
protoxylem elements and generally a protoxylem
lacuna.
In conclusion, the anatomical feature of the
studied swamp plant species reflects the
adaptation of plants to different environmental
variables paralleled with morphological, eco-
physiological and growth responses (Peng et al.,
2017). Moreover, A. donax and P. setaceum could
be good candidates for fiber production industry
due to high content of fibers.
Author contributions
Both authors collected plant samples,
conceived the laboratory work and wrote the
manuscript.
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