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Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/
Journal of Tianjin University Science and Technology
ISSN (Online):0493-2137
E-Publication: Online Open Access
Vol: 57 Issue: 06:2024
DOI: 10.5281/zenodo.11572589
ANATOMICAL VARIATION AMONG ARECACEAE TAXA THROUGH
ROOT SECTION CUTTING BY THE IMPLEMENTATION OF LIGHT AND
SCANNING ELECTRON MICROSCOPY
HAFIZA AYESHA RAHIM
Department of Botany, Lahore College for Women University, Lahore, Pakistan.
Email: ayesharahim098@gmail.com
SHABNUM SHAHEEN *
Department of Botany, Lahore College for Women University, Lahore, Pakistan. *Corresponding
Author Email: shabnum_shaheen78@hotmail.com
GHULAM RASOOL
Institute of Molecular Biology and Biotechnology, University of Lahore, Pakistan.
AMBREEN GUL
Centre of Excellence in Molecular Biology, University of Punjab, Lahore, Pakistan.
FARAH NAZ
Centre of Excellence in Molecular Biology, University of Punjab, Lahore, Pakistan.
Abstract
The Arecaceae family also known as Palmae, is a large group of plants belonging to the Arecales order.
This research involved an anatomical study of transverse sections of roots from various species within the
Arecaceae family. Anatomical studies were done through light and scanning electron microscope. Different
anatomical features Epidermis cells thickness, cortex layers, cortex thickness, rhizodermis thickness, air
spaces, vascular cylinder diameter, xylem, diameter of metaxylem, maximum length of phloem and pith
diameter were examined. The epidermis cells thickness ranges from 17-61 µm. The cortex thickness ranges
from 400-1040 µm. Rhizodermis thickness ranged between 13-35 µm. The maximum pith diameter
observed was almost 820-990 µm in Nannorrhops ritchiana (Griff.) Aitch. Air spces ranged between 13-31
µm. Maximum length of phloem was seen in Dypsis lutescens (H.Wendl.) Beentje & J.Dransf. Dimeter of
metaxylem ranged between 21-108 µm. In conclusion, the root transverse section cutting features exhibited
significant variations, allowing for the differentiation of plants within the Arecaceae family. This is the first
reported study on root section cutting of family Arecaceae species.
Keywords: Arecaceae, Light and Scanning Electron Microscope, Vascular Cylinder Diameter, Metaxylem,
Rhiodermis Thickness, Pith Diameter.
INTRODUCTION
In recent times, there has been a notable increase in research focused on the vegetative
organs of Arecaceae plants. However there remains a substantial knowledge gap
concerning the structural and developmental aspects of vegetative organs especially the
root structures in certain crucial taxa. These taxa are frequently not classified or are
inadequately represented in the latest phylogenetic studies.This deficiency in
June 2024 | 134
Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/
Journal of Tianjin University Science and Technology
ISSN (Online):0493-2137
E-Publication: Online Open Access
Vol: 57 Issue: 06:2024
DOI: 10.5281/zenodo.11572589
understanding can be attributed, in part, to the considerable morphological diversity within
this plant family and the challenges associated with collecting palm organs. (Govaerts &
Dransfield (2015) & Tomlinson et al. 2011).
The root anatomy of plants of family Arecaceae is a fascinating and essential aspect of
their biology and is a subject of profound scientific inquiry and ecological significance.
Plants, belonging to the family Arecaceae, are renowned for their tall, slender trunks and
distinctive fronds. However, beneath the surface, their root system plays a crucial role in
anchoring these towering giants and providing them with the necessary nutrients and
water for survival. Arecaceae roots play an important role, not merely as anchors in the
soil, but as conduits for essential resources, facilitating the tree's growth, survival, and
interaction with its surrounding environment. (Dransfield et al. 2018)
Members of the family Arecaceae, have a distinctive root anatomy that sets them apart
from other types of trees and plants. Arecaceae plants roots exhibit significant differences
when compared to the roots of broadleaf and coniferous trees. These distinctions
primarily stem from their adventitious nature, as they emerge from a specific part of the
trunk known as the root initiation zone. Arecaceae roots have their origins in the outer
portion of the central cylinder, where they connect with vascular bundles within the stem.
As these roots continue to grow, their sheer volume can cause the cortex and pseudobark
to split and expand outward from the base of the stem. (Menezes et al. 2015). Unlike the
roots of dicot plants, Arecaceae plants roots do not possess root hairs. Additionally, due to
the absence of a cambium layer, it is not possible for the roots of neighboring Arecaceae
trees to graft together, as is sometimes observed in dicot trees. Overall, members of
Arecaceae roots are specialized for their unique growth habits and ecological niches.
Their adventitious nature, connection to vascular bundles and absence of cambium are
adaptations that contribute to their success in various tropical and subtropical
environments. (Patrick J & Offler C. (2011).
It's important to note that Arecaceae roots vary widely among different species, and
taxonomic classifications may differ based on the specific characteristics and adaptations
of each species. The taxonomy of Arecaceae roots categorizes them based on various
characteristics and structures. Palm roots are classified into different types and their
categories are according to their functions, location, and appearance. The taxonomy of
palm tree roots also considers the considerable morphological variability observed among
different palm species. Some palms have slender, smooth roots, while others may have
thick, textured roots with various adaptations for their specific ecological niches. Palm root
taxonomy is primarily used to categorize and describe the diverse root structures and
functions within the Arecaceae family. (Henderson, 2011).
June 2024 | 135
Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/
Journal of Tianjin University Science and Technology
ISSN (Online):0493-2137
E-Publication: Online Open Access
Vol: 57 Issue: 06:2024
DOI: 10.5281/zenodo.11572589
MATERIALS AND METHODS Anatomical Preparations
Root samples of the adult plants were collected and the cross sections of the root samples
were cut with a rotary microtome. (Microtome model). The samples were fixed in a mixture
of formaldehyde, glacial acetic acid and ethanol until lab processing. These samples were
then dehydrated with the graded tertiary butyl alcohol series, then they were infiltered and
embedded in the paraplast (58 °C melting point) and then samples were cross-sectioned.
They were then stained with 1 % safranin and 1 5 with acetyl blue and then mounted with
the canada oil and then fixed with the transparent nail polish. (Paiva et al. 2016). These
slides were then examined under light as well as scanning electron microscope. The
images were taken by the digital camera. The root characters were studied following the
methods of Graciano-Ribeiro et al. (2006), with some new characteristics proposed for
specific traits. The description of the anatomical data was also studied by following the
terminology used by the Tomlinson (1961, 1990) and Tomlinson et al. (2011). The main
quantitative studied features were number of layers, epidermal cells shapes and
thickness, number of cortex layers and thickness, number of air spaces and air spaces
lengths, vascular bundle diameter, and number of xylary arches. The number of
metaxylem arch, inner diameter of wide metaxylem arch, maximum length of phloem
strand and pith diameter, were also observed.
Light and Scanning Electron microscope
Root transverse section slides were imaged using both light and scanning electron
microscopes at magnifications of 40X and 100X.
RESULTS Archontophoenix alexandrae (F.Muell.) H.Wendl. & Drude
Root Anatomy Epidermis cells with smooth thick walls ranged from 20-32 µm. There
were almost 51 cortex layers and the cortex thickness observed was 1005-1120 µm.
Rhizodermis observed was single celled and the thickening of the cells varied between
18-21 µm. Air spaces observed varied in number and their number ranged from 22-29 and
were varied in length from 270-310 µm. The vascular cylinder diameter is almost 1120-
1210 µm. The vascular tissue observed was consisted of a number of xylem arches and
the pattern of xylem arches observed was Y shaped, almost 37-41 xylem arches were
observed, 2-4 metaxylem arches were also seen. The inner diameter of the widest
metaxylem arch was 88 µm. The maximum length of the phloem strand observed was 145
µm. The pith diameter observed was almost 290-330 µm. Root hairs were not seen. (Fig
1a, b)
Borassus flabellifer L.
Root Anatomy Epidermis with smooth circular to semi-circular thin walls, epidermis
thickness was 17-19 µm. There were almost 35 cortex layers and the cortex thickness
observed was 840-890 µm. Air spaces were also observed in large numbers and their
number ranged from 15-19 and were varied in length from 260-340 µm. The vascular
June 2024 | 136
Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/
Journal of Tianjin University Science and Technology
ISSN (Online):0493-2137
E-Publication: Online Open Access
Vol: 57 Issue: 06:2024
DOI: 10.5281/zenodo.11572589
cylinder diameter is almost 700-810 µm. The vascular tissue observed was consisted of a
number of xylem arches, almost 17-21 xylem arches were observed, the pattern of xylem
arches observed was “Y” shaped, 2-5 metaxylem arches were also seen. The inner
diameter of the widest metaxylem arch was 43 µm. Short phloem strands were observed
and the maximum length of the phloem strand observed was 70 µm. The pericycle
observed showed one layered cell thickness. The pith diameter observed was almost 170-
230 µm. Root hairs were not seen. (Fig 2a, b) Calamus rotang L.
Root Anatomy Epidermal cells with thick walls measured between 17.5-21 µm. The
cortex consisted of nearly 30 layers, with a thickness ranging from 510-570 µm. A
singlecelled rhizodermis was present, with cell thickening between 13-17 µm. The number
of air spaces varied from 14-20, with lengths ranging from 95-120 µm. The vascular
cylinder had a diameter of approximately 510-720 µm. The vascular tissue contained
numerous xylem arches, arranged in a "Y" pattern, with 17-21.5 xylem arches observed,
and 2-3 metaxylem arches also noted. The widest metaxylem arch had an inner diameter
of 37.5 µm, and the maximum length of the phloem strand was 52 µm. The pith diameter
ranged from 260-300 µm. Root hairs were absent. (Fig 3a, b) Caryota urens L.
Root Anatomy Epidermis cells with thick walls ranged from 30.5-50.5 µm. There were
almost 47 cortex layers and the cortex thickness observed was among 610-840 µm.
Single celled rhizodermis was seen and the thickening of the cells varied between 19-22
µm. Air spaces observed varied in number and their number ranged from 14-21 and were
varied in length from 150-270 µm. The vascular cylinder diameter is almost 970-1220 µm.
The vascular tissue observed was consisted of a number of xylem arches and the pattern
of xylem arches observed was Y shaped, almost 29-34 xylem arches were observed, 59
metaxylem arches were also seen. The inner diameter of the widest metaxylem arch was
87.5 µm. The maximum length of the phloem strand observed was 141 µm. The pith
diameter observed was almost 570-810 µm. Root hairs were not seen. (fig 4a, b)
Chamaedorea cataractrum Mart.
Root Anatomy Epidermis cells with smooth thin walls were observed and their thickness
ranged from 18.5-22.5 µm. There were almost 40 cortex layers and the cortex thickness
observed was among 920-960 µm. Single celled rhizodermis was seen and the thickening
of the cells varied between 15-20 µm. Air spaces observed showed variation in number
and their number ranged from 21-25 and they varied in length from 410-490 µm. The
vascular cylinder diameter is almost 1090-1150 µm. The vascular tissue observed was
consisted of a number of xylem arches and the pattern of xylem arches observed was Y
shaped, almost 27-32 xylem arches were observed, 3-6 metaxylem arches were also
seen. The inner diameter of the widest metaxylem arch was 55.5 µm. The maximum
length of the phloem strand observed was 160 µm. The pith diameter observed was
almost 600-690 µm. Root hairs were not seen. (Fig 5a, b) Chamaerops humilis L.
Root Anatomy Epidermis cells were smooth having thick walls and the thickness of
epidermal cells ranged from 35-42 µm. There were almost 29 cortex layers and the cortex
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Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/
Journal of Tianjin University Science and Technology
ISSN (Online):0493-2137
E-Publication: Online Open Access
Vol: 57 Issue: 06:2024
DOI: 10.5281/zenodo.11572589
thickness observed was 810-920 µm. Single layered rhizodermis was observed and the
thickening of the cells varied between 20-29 µm. Air spaces observed varied in number
and their number ranged from 14-18 and were large in size and varied in length from
180220 µm. The vascular cylinder diameter is almost 770-910 µm. The vascular tissue
observed was consisted of a number of xylem arches and the pattern of xylem arches
observed was “Y” shaped, almost 33-38 xylem arches were observed, 2-5 metaxylem
arches were also seen. The inner diameter of the widest metaxylem arch was 78 µm. The
maximum length of the phloem strand observed was 123 µm. The pith diameter observed
was almost 420-440 µm. Root hairs were not seen. (Fig 6a, b) Dypsis decaryi (Jum.)
Beentje & J.Dransf.
Root Anatomy Epidermis with mostly circular shaped cells having thin walls, thickness
ranged from 23-27 µm. There were almost 50 cortex layers and the cortex thickness
observed was 970-1000 µm. The endodermis seen was single layered and endodermal
cells were thick walled. Air spaces observed varied in number and their number ranged
from 23-31 and were varied in length from 340-370 µm. The vascular cylinder diameter is
almost 990-1010 µm. The vascular tissue observed was consisted of a number of xylem
arches and the pattern of xylem arches observed was “I” shaped, almost 27-29 xylem
arches were observed, 3-6 metaxylem arches were also seen. The inner diameter of the
widest metaxylem arch was 60 µm. The maximum length of the phloem strand observed
was 105 µm. The pericycle observed showed one layered cell thickness. The pith
diameter observed was almost 190-240 µm. Root hairs were not seen. (Fig 7a, b) Dypsis
lutescens (H.Wendl.) Beentje & J.Dransf.
Root Anatomy Epidermis with smooth thin walls having circular to semi-circular shaped
cells, epidermis thickness is varied between 25-30 µm. There were almost 22 cortex
layers and the cortex thickness observed was almost 800-850 µm. The exodermis cells
observed were with thin walls, parenchyma cells observed showed variable cell diameter
from 520-840 µm. Air spaces were also observed in large numbers and their number
ranged from 15-19 and were almost varied in length from 260-340 µm. The vascular
cylinder diameter measured was almost 700-810 µm. The vascular tissue observed was
consisted of a number of xylem arches, almost 17-21 xylem arches were observed and
the pattern of xylem arches observed was “Y” shaped, 2-5 metaxylem arches were also
seen. The inner diameter of the widest metaxylem arch was 43 µm. The maximum length
of the phloem strand observed was 170 µm. The pericycle observed showed one layered
cell thickness. The pith diameter observed was almost 170-230 µm. Root hairs were not
seen. (Fig 8a, b)
Hyophorbe lagenicaulis (L.H.Bailey) H.E.Moore
Root Anatomy Epidermis with smooth circular to semi-circular thin walls, epidermis
thickness is 19-23 µm. A one layered rhizodermis was observed with rectangular to
quadrangular shaped cells, the thickening of the cells varied between 15-21 µm. There
were almost 10 cortex layers and the cortex thickness observed was 400-500 µm. The
June 2024 | 138
Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/
Journal of Tianjin University Science and Technology
ISSN (Online):0493-2137
E-Publication: Online Open Access
Vol: 57 Issue: 06:2024
DOI: 10.5281/zenodo.11572589
quadrangular cells were observed in exodermis. Parenchyma cells observed showed
variable cell diameter from 520-840 µm. Air spaces were also observed in large numbers
and their number ranged from 18-21 and were varied in length from 250-360 µm. The
vascular cylinder diameter is almost 760-890 µm. The vascular tissue observed was
consisted of a number of xylem arches, almost 20-30 xylem arches were observed and
the pattern of xylem arches observed was “Y” shaped, 2-5 metaxylem arches were also
seen. The inner diameter of the widest metaxylem arch was 55 µm. The maximum length
of the phloem strand observed was 110 µm. The pericycle observed showed one layered
cell thickness. The pith diameter observed was almost 200-290 µm. Root hairs were not
seen. (Fig 9a, b)
Hyphaene thebaica (L.) Mart.
Root Anatomy Epidermis cells were semi-circular to circular shaped having thick walls
and their size ranged from 30-37 µm. There were almost 49 cortex layers and the cortex
thickness observed was 1009-1120 µm. Air spaces observed varied in number and their
number ranged from 20-23 and were varied in length from 360-440 µm. The vascular
cylinder diameter was almost 1022-1170 µm. The vascular tissue observed was consisted
of a number of xylem arches, almost 32-41 xylem arches were observed and the pattern
of xylem arches observed was “I” shaped, 4-7 metaxylem arches were also seen. The
inner diameter of the widest metaxylem arch was 108 µm. The maximum length of the
phloem strand observed was 102 µm. The pith diameter observed was almost 600770
µm. Root hairs were not seen. (Fig 10a, b) Livistonia chinensis (Jacq.) R.Br. ex-Mart.
Root Anatomy Epidermis cells having thick walls ranged from 50-55 µm. There were
almost 42 cortex layers and the cortex thickness observed was among 690-800 µm. One
celled rhizodermis was seen and the thickening of the cells varied between 14-16 µm. Air
spaces observed varied in number and their number ranged from 14-20 and were varied
in length from 270-340 µm. The vascular cylinder diameter is almost 770-900 µm. The
vascular tissue observed was consisted of a number of xylem arches and the pattern of
xylem arches observed was “I” shaped, almost 26-50 xylem arches were observed, 1-3
metaxylem arches were also seen. The inner diameter of the widest metaxylem arch was
78.5 µm. The maximum length of the phloem strand observed was 134 µm. The pith
diameter observed was almost 370-520 µm. Root hairs were not seen. (Fig 11a, b)
Nannorrhops ritchiana (Griff.) Aitch.
Root Anatomy Epidermis cells have smooth thick walls and their thickness ranged from
33.5-41.5 µm. There were almost 47 cortex layers and the cortex thickness observed was
among 820-860 µm. Single celled rhizodermis was seen and the thickening of the cells
varied between 14-17 µm. Air spaces observed were ranged in number from 19-23 and
were varied in length from 370-410 µm. The vascular cylinder diameter is almost
11901250 µm. The vascular tissue observed was consisted of a number of xylem arches
and the pattern of xylem arches observed was “I” shaped, almost 37-42 xylem arches
were observed, 2-5 metaxylem arches were also seen. The inner diameter of the widest
June 2024 | 139
Tianjin Daxue Xuebao (Ziran Kexue yu Gongcheng Jishu Ban)/
Journal of Tianjin University Science and Technology
ISSN (Online):0493-2137
E-Publication: Online Open Access
Vol: 57 Issue: 06:2024
DOI: 10.5281/zenodo.11572589
metaxylem arch was 95.5 µm. The maximum length of the phloem strand observed was
146.5 µm. The pith diameter observed was almost 820-990 µm. Root hairs were present.
(Fig 12a, b)
Phoenix canariensis Hort. ex Chabaud.
Root Anatomy Epidermis cells with smooth thick walls were observed and their thickness
ranged from 53.5-61 µm. There were almost 60 cortex layers and the cortex thickness
observed was among 1020-1040 µm. Single celled rhizodermis was seen and the
thickening of the cells varied between 13-18 µm. Air spaces observed varied in number
and their number ranged from 20-23 and were varied in length from 360-380 µm. The
vascular cylinder diameter is almost 1030-1050 µm. The vascular tissue observed was
consisted of a number of xylem arches, almost 25.5-29 xylem arches were observed and
the pattern of xylem arches observed was Y shaped, 4-6 metaxylem arches were also
seen. The inner diameter of the widest metaxylem arch was 70.5 µm. The maximum
length of the phloem strand observed was 129.5 µm. The pith diameter observed was
almost 470-490 µm. Root hairs were not seen. (Fig 13a, b) Phoenix dactylifera L.
Root Anatomy The epidermis displayed thick walls with a thickness ranging from 35-40
µm and the epidermal cells appeared slightly elongated. A single-layered rhizodermis was
observed, featuring rectangular to quadrangular cells with thickening between 20-25 µm.
The cortex consisted of nearly 38 layers, with a total thickness of 970-1020 µm.
Parenchyma cells were present, generally semicircular to circular in shape. Air spaces
were observed, numbering 13-14 with lengths varying from 80-85 µm. The vascular
cylinder had a diameter of approximately 500-550 µm and contained numerous xylem
arches, specifically 15-20 arranged in a "Y" pattern, with 2-4 metaxylem arches also
noted. The widest metaxylem arch had an inner diameter of 21 µm and the maximum
length of the phloem strand was 70 µm. The pericycle was composed of a single cell layer
and the pith diameter measured around 120-150 µm. Root hairs were absent. (Fig 14a, b)
Phoenix sylvestris (L.) Roxb.
Root Anatomy Epidermis cells having thick walls ranged from 51-56 µm. There were
almost 39 cortex layers and the cortex thickness observed was among 600-700 µm. One
celled rhizodermis was seen and the thickening of the cells varied between 15-19 µm. Air
spaces observed varied in number and their number ranged from 16-19 and were varied
in length from 370-440 µm. The vascular cylinder diameter is almost 700-900 µm. The
vascular tissue observed was consisted of a number of xylem arches and the pattern of
xylem arches observed was “I” shaped, almost 20-35 xylem arches were observed, 1-3
metaxylem arches were also seen. The inner diameter of the widest metaxylem arch was
72 µm. The maximum length of the phloem strand observed was 129 µm. The pith
diameter observed was almost 300-430 µm. Root hairs were not seen. (Fig 15a, b)
Raphia vinifera P. Beauv.
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DOI: 10.5281/zenodo.11572589
Epidermis cells having thick walls ranged from 50-54 µm. There were almost 29 cortex
layers and the cortex thickness observed was among 650-700 µm. One celled
rhizodermis was seen and the thickening of the cells varied between 14-18 µm. Air spaces
observed varied in number and their number ranged from 13-17 and were varied in length
from 350-410 µm. The vascular cylinder diameter is almost 700-800 µm. The vascular
tissue observed was consisted of a number of xylem arches and the pattern of xylem
arches observed was “I” shaped, almost 25-30 xylem arches were observed, 1-2
metaxylem arches were also seen. The inner diameter of the widest metaxylem arch was
62 µm. The maximum length of the phloem strand observed was 122 µm. The pith
diameter observed was almost 310-420 µm. Root hairs were not seen. (Fig16a, b)
Raphis excelsa (Thunb.) Henry
Root Anatomy Epidermis cells observed were thin having circular shaped cells and their
size ranged from 17-33 µm. There were almost 41 cortex layers and the cortex thickness
observed was 905-1010 µm. Rhizodermis observed was single celled and the thickening
of the cells varied between 17-20 µm. Air spaces observed varied in number and their
number ranged from 13-18 and were varied in length from 288-410 µm. The vascular
cylinder diameter is almost 1000-1110 µm. The vascular tissue observed was consisted of
a number of xylem arches and the pattern of xylem arches observed was Y shaped,
almost 16-24 xylem arches were observed, 1-3 metaxylem arches were also seen. The
inner diameter of the widest metaxylem arch was 110 µm. The maximum length of the
phloem strand observed was 95 µm. The pith diameter observed was almost 200-230 µm.
Root hairs were not seen. (Fig 17a, b)
Syagrus romanzoffiana (Cham.) Glassman
Root Anatomy Epidermis with thick walls was observed and the thickness observed was
45-50 µm. The epidermal cells observed were slightly elongated in shape. One layered
rhizodermis was also observed with rectangular to quadrangular shaped cells, the
thickening of the cells varied between 30-35 µm. There were almost 38 cortex layers and
the cortex thickness observed was 980-1050 µm. Parenchyma cells were present and
common semicircular to circular in shape. Air spaces observed ranged in number from 14-
16 and were almost varied in length from 90-95 µm. The vascular cylinder diameter
observed was almost 600--650 µm. The vascular tissue observed was consisted of a
number of xylem arches, almost 15-18 xylem arches were observed and the pattern of
xylem arches observed was “Y” shaped, 3-4 metaxylem arches were also seen. The inner
diameter of the widest metaxylem arch was 31 µm. The maximum length of the phloem
strand observed was 80 µm. The pericycle observed showed one layered cell thickness.
The pith diameter observed was almost 130-170 µm. Root hairs were not seen. (Fig 18a,
b)
Washingtonia robusta H.Wendl.
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DOI: 10.5281/zenodo.11572589
Root Anatomy Epidermis cells have thick walls ranged from 19.5-31 µm. There were
almost 31 cortex layers and the cortex thickness observed was among 520-540 µm.
Single celled rhizodermis was seen and the thickening of the cells varied between 13-15
µm. Air spaces observed varied in number and their number ranged from 13-17 and were
varied in length from 95-100 µm. The vascular cylinder diameter is almost 520-790 µm.
The vascular tissue observed was consisted of a number of xylem arches and the pattern
of xylem arches observed was Y shaped, almost 18-20.5 xylem arches were observed, 2-
4 metaxylem arches were also seen. The inner diameter of the widest metaxylem arch
was 39.5 µm. The maximum length of the phloem strand observed was 54 µm. The pith
diameter observed was almost 270-310 µm. Root hairs were not seen. (Fig 19a, b)
Wodyetia bifurcata A.K.Irvine
Root Anatomy Epidermal cells with thick walls measured between 50-53 µm. The cortex
comprised nearly 30 layers, with a thickness ranging from 600-640 µm. A single-celled
rhizodermis was present, with cell thickening varying between 15-19 µm. The number of
air spaces ranged from 13-16, with lengths varying from 340-410 µm. The diameter of the
vascular cylinder was approximately 500-600 µm. The vascular tissue included numerous
xylem arches, arranged in an "I" pattern, with 25-30 xylem arches observed, and 2-4
metaxylem arches also noted. The widest metaxylem arch had an inner diameter of 62
µm, and the maximum length of the phloem strand was 127 µm. The pith diameter
measured around 200-320 µm. Root hairs were absent. (Fig 20a, b)
Fig 1: a. T.S of Archontophoenix alexandrae (F.Muell.) H.Wendl. & Drude showing
thick epidermal cells
b. T.S of Archontophoenix alexandrae (F.Muell.) H.Wendl. & Drude showing SEM
image of thick epidermal cell layer along with air channels and vascular bundles
June 2024 | 142
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Fig 2: a. T.S of Borassus flabellifer L. leaf showing air channels
b. T.S of Borassus flabellifer L. leaf showing cortex layers
Fig 3: a. T.S of Calamus rotang L. (LM) showing exodermis, phloem and xylem
vessels
b. T.S of Calamus rotang L. SEM of root xylem vessels
Fig 4: a. T.S of Caryota urens L. showing endodermis, cortex cells and pith
b. T.S of Caryota urens L. showing thick cortical cells
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DOI: 10.5281/zenodo.11572589
Fig 5: a. T.S of Chamaedorea cataractrum Mart (LM)
b. T.S of Chamaedorea cataractrum Mart (SEM)
Fig 5: a. T.S of Chamaerops humilis L. showing large air spaces
b. T.S of Chamaerops humilis L. showing SEM image of large air spaces
Fig 7: a. TS of Dypsis decaryi (Jum.) Beentje & J.Dransf. Showing
b. TS of Dypsis decaryi (Jum.) Beentje & J.Dransf. Showing vascular bundle and
cortex cells
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Fig 8: a. TS of Dypsis lutescens (H.Wendl.) Beentje & J.Dransf showing “Y”
shaped xylem arches
b. TS of Dypsis lutescens (H.Wendl.) Beentje & J.Dransf showing thin walled
endodermis
Fig 9 a. TS of Hyophorbe lagenicaulis (L.H.Bailey) H.E.Moore showing vascular
bundles
b. TS of Hyophorbe lagenicaulis (L.H.Bailey) H.E.Moore showing single layered
rhizodermis layer
Fig 10: a. TS of Hyphaene thebaica (L.) Mart showing
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b. TS of Hyphaene thebaica (L.) Mart showing cortex cells
Fig 11: a. TS of Livistonia chinensis (Jacq.) R.Br. ex-Mart. showing air
channelsand vascular bundles
b. TS of Livistonia chinensis (Jacq.) R.Br. ex-Mart. showing SEM image of thick-
walled cortical cells
Fig 12: a. TS of Nannorrhops ritchiana (Griff.) Aitch. (LM)
b. TS of Nannorrhops ritchiana (Griff.) Aitch. (SEM)
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Fig 13: a. TS of Phoenix canariensis Hort. ex Chabaud showing I shaped xylem
arches
b. TS of Phoenix canariensis Hort. ex Chabaud (SEM)
Fig 14: a. Phoenix dactylifera L. showing smooth xylem vessels
b. Phoenix dactylifera L. showng Polygonal shaped parenchyma cells
Fig 15: a. TS of Phoenix sylvestris (L.) Roxb. Showing cortex layers and vascular
bundle
b. TS of Phoenix sylvestris (L.) Roxb. Showing cortex layers and endodermis
Fig 16: a. Raphia vinifera P. Beauv. Showing exodermis and xylem vessels
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b. SEM. showing endodermis and medullary rays
Fig 17: a. TS of Raphis excelsa (Thunb.) Henry showing a large number of cortex
layers
b. TS of Raphis excelsa (Thunb.) Henry showing SEM image of cortex layers
along with air channel
Fig 18: a.: TS of Syagrus romanzoffiana (Cham.) Glassman showing large air
channels
b. TS of Syagrus romanzoffiana (Cham.) Glassman showing endodermis and
phloem
Fig 19: a. TS of Washingtonia robusta H.Wendl.showing vascular bundle
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b. TS of Washingtonia robusta H.Wendl. Showing Y-shaped xylem arches
Fig 20: T. S of Wodyetia bifurcata A.K.Irvine (LM) showing thick endodermis and
vascular bundles
b. T. S of Wodyetia bifurcata A.K.Irvine (SM) showing cortex parenchyma and
phloem
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Table 1: Quantitative study of various parameters of root transverse section cutting of Arecaceae Species
Sr
no. Plant names
Epidermi
s cells
thicknes
s
(µm)
Cort
ex
layer
s
(µm)
Cortex
thickness
(µm)
Rhizod
ermis
thickne
ss
(µm)
Air
spaces
(µm)
Vascular
cylinder
diameter
(µm)
Xylem
arches
(µm)
Metax
ylem
arch
(µm)
Diamet
er of
metaxy
lem
(µm)
Maximu
m
length
of the
phloem
(µm)
Pith
Diameter
(µm)
1 Archontophoenix
alexandrae
(F.Muell.)
H.Wendl. & Drude
20-32 51 1005-1120 18-21 22-29 1120-1210 37-41 2-4 88 145 290-330
2 Borassus
flabellifer L. 17-19 35 840-890 - 15-19 700-810 17-21 2-5 43 70 170-230
3 Calamus rotang
L. 17.5-21 30 510-570 13-17 14-20 510-720 17-21.5 2-3 37.5 52 260-300
4 Caryota urens L. 30.5-50.5 47 610-840 19-22 14-21 970-1220 29.5-34 5-9 87.5 141 570-810
5 Chamaedorea
cataractrum Mart. 18.5-22.5 40 920-960 15-20 21-25 1090-1150 27-32 3-6 55.5 160 600-690
6 Chamaerops
humilis L. 35-42 29 810-920 20-29 14-18 770-910 33-38 2-5 78 123 420-440
7 Dypsis decaryi
(Jum.) Beentje &
J. Dransf.
23-27 50 970-1000 23-31 23-31 990-1010 27-29 3-6 60 105 190-240
8 Dypsis lutescens
(H.Wendl.)
Beentje &
J.Dransf.
25-30 - 800-850 - 15-19 700-810 17-21 2-5 43 170 170-230
9 Hyophorbe
lagenicaulis
(L.H.Bailey)
H.E.Moore
19-23 10 400-450 15-21 - 760-890 20-30 2-5 55 110 200-290
10 Hyphaene
thebaica
(L.)
30-37 49 1009-1120 - 20-23 1022-1170 32-41 4-7 108 102 600-770
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Mart.
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11 Livistonia
chinensis (Jacq.)
R.Br. ex M
50-55 42 690-800 14-16 14-20 770-900 26-50 1-3 78.5 134 370-520
12 Nannorrhops
ritchiana(Griff.)
Aitch.
33.5-41.5 47 820-860 14-17 19-23 1190-1250 37-42 2-5 95.5 146.5 820-990
13 Phoenix
canariensis Hort.
ex Chabaud.
53.5-61 60 1020-1040 13-18 20-23 1030-1050 25.5-29 4-6 70.5 129.5 470-490
14 Phoenix
dactylifera L. 35-40 38 970-1020 20-25 13-14 500-550 15-20 2-4 21 70 120-150
15 Phoenix
sylvestris
(L.) Roxb.
51-56 39 600-700 15-19 16-19 700-900 20-35 1-3 72 129 300-430
16 Raphia vinifera P.
Beauv. 50-54 29 650-700 14-18 13-17 700-800 25-30 1-2 62 122 310-420
17 Rhapis excelsa
(Thunb.) A.Henry 17-33 905-1010 17-20 1000-1110 16-24 1-3 110 95 200-230
18 Syagrus
romanzoffiana
(Cham.)
Glassman
45-50 38 980-1050 30-35 14-16 600--650 15-18 3-4 31 80 130-170
19 Washingtonia
robusta H.Wendl. 19.5-31 31 520-540 13-15 13-17 520-790 18-20.5 2-4 39.5 54 270-310
20 Wodyetia
bifurcata
A.K.Irvine
50-53 30 600-640 15-19 13-16 500-600 25-30 2-4 62 127 200-320
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Fig 21: Comparison among various parameters of root transverse section cutting
of Arecaceae species
DISCUSSION
This is the first time that the root anatomy of these species is done in Pakistan.
In the present studies the general anatomical characteristics observed in root of
Arecaceae taxa were in agreement with those pointed out by the Tomlinson et al. (2011)
and the present studies highlights some significant root anatomical parameters which can
be helpful in plant species identification and differentiation.
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In this research work most of the species in their transverse section of root anatomy show
single layered rhizodermis having rectangular to quadrangular shape. According to a
number of authors (Henderson et al. 2005, Ahmad et al. 2017 and Seubert, 2019) one of
the main features of the rhizodermis is the root hair development however according to
present studies no root hairs were seen in all the studied Arecaceae taxa. According to
Tomlinson et al. (2011) the development of the hairy layer in Arecaceae taxa is present in
very thin roots. The epidermis and epidermal cells in the present studies showed variation.
Some species (Borassus flabellifer L., Dypsis lutescens (H.Wendl.), Dypsis decaryi (Jum.)
Beentje & J.Dransf Beentje & J.Dransf, Hyophorbe lagenicaulis (L.H.Bailey) H.E.Moore
and Raphis excelsa (Thunb.) Henry showed smooth thin walls while the remaining
species showed thick smooth walls. According to Enstone et al. 2003 the cell walls
thickening can be associated to the protection against pathogens attack and dehydration.
In the present research work all the species had semicircular to circular shaped epidermal
cells. Allen et al. 2013 in his studies also discussed the semi-circular to circular shaped
epidermal shaped cells in the species of genus Geonoma of family Arecaceae which
confirms the findings of the present studies.
In the present investigation the cortex showed variations among different species with
respect to number of layers and thickness. The minimum number of cortex layers
observed was 10 Hyophorbe lagenicaulis (L.H.Bailey) H.E.Moore and the maximum
number of cortex layers observed was 60 in Phoenix reobeleni O'Brien. Variations were
also observed in cortex thickenings. The minimum thickening 400-450 µm was observed
in Hyophorbe lagenicaulis (L.H.Bailey) H.E.Moore and the maximum thickening
10201040 µm was observed in Phoenix canariensis Hort. ex Chabaud. The existence of
abundant air spaces also called air channels in Arecaceae taxa is remarkable. According
to Seubert 2019 these air spaces have a lysogenous origin and may be variable in size
and this variability in the species depends on the intensity of the procedure that created
them. According to Flores-Vindas, 2019 the presence of air spaces is common in
Arecaceae taxa but it is also noted in many other monocots. The air spaces in the studied
taxa showed a lot of variation in number and length. The variation was also seen in the
length of the air spaces. The minimum length (90-95 µm) of air spaces was observed in S
yagrus romanzoffiana (Cham.) Glassman whereas the maximum length (410-490 µm) of
air spaces was observed in Chamaedorea cataractrum Mart.
The vascular cylinder is determined by the pericycle layer and the vascular bundle
diameter showed a lot of variation in the studied taxa. The lowest diameter of vascular
bundle (520-790 µm) was observed in Washingtonia robusta H.Wendl. Whereas the
highest vascular bundle diameter (1190-1250 µm) was observed in Nannorrhops
ritchiana (Griff.) Aitch. In the studied species the vascular bundle was composed of xylary
arches which were variable in number in different species. All the species showed “Y”
shaped pattern of xylem arches except Dypsis decaryi (Jum.) Beentje & J.Dransf,
Hyphaene thebaica (L.) Mart, Livistonia chinensis (Jacq.) R.Br. ex-Mart, and
Nannorrhops ritchiana (Griff.) Aitch which showed “I’ shaped xylem arches. The
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metaxylem vessels number per arch and their diameter was also variable in the different
studied taxa. The minimum number of metaxylem arches (1-3) were seen in Livistonia
chinensis (Jacq.) R.Br. ex-Mart. The maximum number of metaxylem arches (5-9) was
seen in Caryota urens L. The minimum inner diameter of the widest metaxylem arch (31
µm) was observed in Syagrus romanzoffiana (Cham.) Glassman. The maximum inner
diameter of the widest metaxylem arch (110 µm) was observed in Raphis excelsa
(Thunb.) Henry. Briceño et al. 2021 in his studies examined that the maximum number of
metaxylem arches were in G. orbignyana and the minimum were in G. pinnatifrons.
Similarly, the maximum inner diameter of the widest metaxylem arch was seen in G.
undata and the minimum was observed in G. spinescens while studying the genus genus
Geonoma of Arecaceae family. The phloem strands are conspicuous and their length
varies in different taxa. In present studies the maximum length of the phloem strand
observed was 170 µm in Dypsis lutescens (H.Wendl.) Beentje & J.Dransf. Whereas the
minimum length of the phloem strand observed was 54 µm in Cocothrinax argentata
(Jacq.) L.H.Bailey. Variation was also seen in pith diameter during the transverse section
cutting of root in the present research work. The maximum pith diameter observed was
almost 820-990 µm in Nannorrhops ritchiana (Griff.) Aitch. Whereas the minimum pith
diameter observed was almost 130-170 µm in Syagrus romanzoffiana (Cham.)
Glassman.
CONCLUSION
This anatomical study of root transverse section cutting was done first time by utilizing
light and scanning electron microscope. The anatomical study of root transverse sections
in Arecaceae species has revealed distinct morphological features that are crucial for their
identification and classification. The variations in root structure among the studied species
provide valuable insights into their adaptability, nutrient uptake mechanisms, and overall
plant health. These findings not only enhance our understanding of the anatomical
diversity within the Arecaceae family but also have practical implications for agriculture
and horticulture. By improving the ability to distinguish between species, this research can
aid in the development of more targeted cultivation practices, leading to better crop
management and increased economic benefits. Furthermore, the study highlights the
importance of detailed anatomical analysis in plant taxonomy and its potential
applications in improving crop resilience and productivity.
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