INTRODUCTION
The genus Ficus is among the
premier genera of shrubs and trees, which are known for its medicinal, socioeconomic and religious importance. As regards its
medicinal importance, the Ficus spp. are known to biosynthesize
bioactive compounds including phenolics, flavonoids, terpenes etc., which are
used to treat the ailments such as diabetes, toothache, gum infection, piles
etc. (Salehi et al. 2021; Devi et al. 2022). Interestingly all parts of
plant including bark, roots, leaves and fruits are
used in the treatment of various ailments (Murugesu et al. 2021).
Morphological features of
plants have close association with the biochemical pathways operative in leaves
and other parts (Klem et al. 2019). Photosynthesis, which depends upon
the stomatal functions in the exchange of water and gases, is one of the
fundamental processes involved in the production of primary and secondary
metabolites. Hence, the stomatal density and function in the leaves may directly
influence the synthesis of primary metabolites and indirectly the secondary
metabolites (Ördög et al. 2013).
Plants have historically been
categorised according to the appearance of their fruits and blooms. In order to accurately identify and classify closely related
taxa, plant scientists have been using leaf epidermal morphology (Abdulrahaman
and Oladele 2010; Qiu et al. 2023; Hussain et al. 2025). Moreover,
to differentiate between various taxonomic ranks, such as families, tribes,
genera, and species, morphological traits are essential (Alaida and Aldhebiani
2022). However, several species of flowering plants have similar morphological
attributes, so it might be difficult to differentiate them based only on
morphological traits (Nazir et al. 2013). Determining the taxonomic
placements of these species thus requires an awareness of both the similarities
and differences within a sub-genus. Numerous crucial micromorphological
characteristics were identified through the examination of Ficus
epidermal surfaces; some of these features exhibit noteworthy interspecific
variations that are significant from a taxonomical standpoint (Mubo et al.
2004).
Essential diagnostic features
of the epidermis that offer helpful suggestions for identification include
size, stomata orientation, stomata form, guard cell shape, and structural
features of epidermal cells (Munir et al. 2011; Trofimov and Rohwer 2018).
In a related study, it was shown that trichome size and shape, stomata size and
form, and the presence or absence of stomatal clusters were useful diagnostic
traits for differentiating distinct fern species (Rahman et al. 2017).
Although it is now thought
that epidermal traits are important for taxonomy, there is little information
on the epidermal morphology of Ficus (Hussain et al. 2025).
Notable characteristics such as epidermal cell structure, shape, orientation,
stomatal complex size, and trichome types have major taxonomic implications
(Rahman et al. 2017).
Leaf is the source tissue
where the biosynthesis of majority of medicinally and economically important
compounds takes place. Ficus is an important genus known for the
synthesis of quite a few metabolites of medicinal value (Devi et al.
2022), which may be associated to the metabolite profiles. Thus, the current
study was conducted to gain a comprehensive understanding of the importance of
leaf epidermal structure in the identification of F. elastica, F.
elastica and F. natalensis. This study will add to the existing
literature on the use of leaf epidermal architecture in plant identification
and provide insights for researchers and practitioners in plant taxonomy and
categorisation.
MATERIALS AND
METHODS
An
experiment was conducted in order to explore stomatal
modifications in lower leaf lamina, petiole length and leaf surface area of
different Ficus species in November, December and January. The leaves
were collected from the New Botanical Garden, University of Agriculture,
Faisalabad. Samples were preserved in FAA (formaldehyde-acetone-alcohol)
fixative for 24 hours and then shifted to 70% ethanol for preservation. The
hand sectioning of the leaf lamina was performed. The leaf lamina was peeled
off from the selected leaf samples and immediately placed in 30% ethanol for 10–15
minutes. These tissues were shifted to 50% ethanol, followed by 70% ethanol for
10–15 minutes, respectively. After 70% ethanol treatment, a few drops of
safranin were added for 5 minutes. Safranin with 90% ethanol was used for 5 minutes.
Then samples were washed 2–3 times with 100% ethanol. The samples were treated
with 25%, 50% and 100% xylene for clearing them. Each section was permanently
preserved in a drop of Canada balsam. The images of the samples were taken
under an electron microscope.
RESULTS
Length of petiole
The comparison of different Ficus
species petiole length recorded at different intervals (November, December and January) showed significant variations. Data
showed a gradual increase in the petiole length of F. elastica over time.
In contrast, F. natalensis consistently exhibited the minimum petiole
length throughout all the experimental months, whereas other Ficus
species showed no specific pattern in increase or decrease in length (Fig. 1A).
Leaf area
Results revealed that F.
elastica var. varigata leaf area was decreased from November to
December and again increased from December to January. The F. natalensis
had the smallest leaf area but remained constant throughout all the
experimental months (Fig. 1B).
Number of stomata
The comparison of Ficus species
leaves epidermis collected at different time intervals (dawn, dusk, mid-day) in
winter months revealed that there’s a subsequent increase in the opening of
stomata during mid-day. Among the species studied, F. natalensis had the
maximum no. of stomata in November and December, but in January, F. elastica
var. varigata had the maximum no. of stomata. Moreover, F. elastica
‘Burgundy’ had the least no. of stomata in almost all data taking months (Fig. 1C).
Number of subsidiary cells
Data showed that F.
natalensis showed the maximum no. of stomata and F. hawai and F.
macrophylla had the least no. of subsidiary cells (Fig. 1D).
Stomatal pore area
Results showed that the stomatal pore size of F.
macrophylla and F. elastica ‘Burgundy’ gradually increased across
the observation periods, while F. natalensis pore size increased from November
to December and then decreased from December to January (Fig. 2A–4).
+24010105+Final+Approved+Medicinal+Plants+Ali+Nawaz_files/image028.png)
Length of guard cells
The comparison of different Ficus
species based on the length of guard cells recorded at different intervals in
winter months (November, December and January) showed
subsequent variations (Fig. 3–4). Results showed that the length of the guard
cells of F. elastica gradually decreased over time, while the length of the
guard cells of F. hawai increased across the observation periods (Fig. 2B).
+24010105+Final+Approved+Medicinal+Plants+Ali+Nawaz_files/image029.png)
Width of guard cell
The results for guard cell
width showed a gradual increase over time in F. macrophylla, whereas in F.
elastica, guard cell width decreased with the passage of time (Fig. 7).
DISCUSSION
The genus Ficus, commonly referred to
as fig, belongs to the family Musaceae.
Ficus is one of the largest plant genera, with more than 750
described species distributed worldwide, mainly in tropical countries. Fig
trees are often ecologically important ‘Keystone’ components of tropical
forests, because of the large number of vertebrates that feed on their figs,
more than any other group of plants (Hussain et al. 2025).
A
study was conducted to compare different morphological and anatomical characteristics
of Ficus species. The result revealed that F. elastica had the maximum
number of stomata, and the least were found in F. natalensis. The
petiole length of F. elastica var. varigata increased over time.
Over time, plants evolved different mechanisms to optimise their stomatal
density in response to environmental cues to enhance their survival and fitness
(Hou et al. 2023) (Fig. 1–2). Moreover, F. natalensis had shorter
petiole length and showed no specific pattern in the increase and decrease in
length during the observation period. The leaf area of F. elastica var. varigata
decreased from November to +24010105+Final+Approved+Medicinal+Plants+Ali+Nawaz_files/image030.png)
December. and again, increased from December
to January. In contrast, Shrestha et al. 2025) reported non-significant
changes in the leaf area of F. religiosa during the winter season. In
contrast, F. natalensis had the smallest leaf area, and no variation was
marked from November to January. Furthermore, F. natalensis had the maximum
number of stomata, and F. hawai and F. macrophylla had the least
number of subsidiary cells. Stomatal pore area of F. macrophylla and F.
elastica ‘Burgundy’ gradually increased with the passage of time, while F.
natalensis pore area increased from November to December and then decreased
from December to January (Fig. 3–4). Stomatal pore size or movement follows
circadian rhythm, which is influenced by light exposure and the plants internal
clock (Hou et al. 2023).
The
length of the guard cell of F. elastica gradually decreased over time, while
in F. hawai it increased from November till January. In addition, the width
of the guard cells of F. macrophylla gradually increased across the
observation period, and in F. elastica the guard cell width decreased,
respectively (Fig 1–4). Plants are affected by the environmental conditions
during all phases of growth and development. Especially, stomatal number
reportedly changes when plants are grown in different seasons. Although the measurements
were done on an area basis, this approach does not account for possible
anatomical changes during different environmental conditions. It seems likely
that the stomatal pattern may operate and respond to a range +24010105+Final+Approved+Medicinal+Plants+Ali+Nawaz_files/image031.png)
of conditions that can be
explored in further studies. Stomata frequency declined in response to
increasing CO2 and may have occurred over geological time (Hofmann et
al. 2025).
CONCLUSIONS
changes in the number of epidermal cells, such
as the number of stomata and subsidiary cells of Ficus species, were
greatly affected by the environmental and climatic changes. These differences
highlight the adaptive responses of each species to seasonal and diurnal
changes. This study highlighted the taxonomic importance of leaf epidermal
features, emphasising their effectiveness as diagnostic traits for
distinguishing among Ficus species. Future research should focus on the
molecular and physiological mechanisms underlying stomatal regulation and
anatomical adaptations in Ficus species under varying environmental conditions.
Long-term field studies and genetic analyses could provide deeper insights into
their adaptive strategies.
ACKNOWLEDGMENTS
The
author expresses his sincere gratitude to the Department of Botany, University
of Agriculture, Faisalabad, for providing facilities for this work.
DATA AVAILABILITY
The data will be made available on a fair
request.
ETHICS APPROVAL
Not applicable to this paper.
FUNDING SOURCE
This project is not funded by any agency.
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