Systematics study through scanning electron microscopy; a tool for the authentication of herbal drug Mentha suaveolens Ehrh

From macro to micro: A close-up look at Hydrangea luteovenosa and Hydrangea serrata

Understanding the anatomical traits of the foliar epidermis is essential for making precise species identification and categorization. In this study, scanning electron microscopy (SEM) was used to examine the taxonomically significant foliar epidermal traits of Hydrangea luteovenosa and H. serrata. The qualitative and quantitative traits observed included the epidermal cell form, cuticle presence, trichome morphology, stomatal type, and guard cell features. H. serrata had a thin and smooth cuticle, and epidermal cells organized compactly into cubic or hexagonal shapes. The stomata were of the anomocytic type and dispersed, while the trichomes were straightforward, unbranched, and distributed sparsely. The guard cells had distinct cell walls and a kidney-shaped morphology. These crucial traits for taxonomy were in line with an epidermis composed of three to five layers. Similar polygonal epidermal cells with a compact arrangement were observed in H. luteovenosa, together with a thin and smooth cuticle. The stomata were anomocytic and dispersed, while the trichomes were straightforward, unbranched, and sparsely distributed. The guard cells have distinct cell walls and a kidney-shaped morphology. The traits were indicative of an epidermal structure with three to five layers. These traits helped correctly identify and categorize these two species of Hydrangea. In addition to assisting in the taxonomic classification of these species and advancing knowledge of their ecological and evolutionary links, the SEM study provided insightful information into the structural variety of these species. RESEARCH HIGHLIGHTS: Microscopic characteristics of H. luteovenosa and H. serrata Understanding the anatomical traits of the foliar epidermis is essential for precise species identification and categorization.

Taxonomic studies based on leaf epidermal microanatomy using high-resolution microscopy in Lamiaceous species and their antimicrobial effects

The knowledge of essential oil antimicrobial activity of Lamiaceous species is assessed to describe its effects. The comprehensive foliar trichomes and stomatal morphology of the leaves of essential oil-bearing plants from the family Lamiaceae revealed diverse antimicrobial properties. The aim of this study was to investigate the foliar anatomical traits of 19 Lamiaceous taxa belonging to different tribes using light and scanning electron microscopy to correctly diagnose the species. The microanatomy of the foliar epidermis, trichomes diversity, and the stomatal apertural complex was visualized. Quantitative measurements were noted to describe the variations and the qualitative aspects for example, polygonal shape epidermal cells were examined. The stomatal aperture of four types and trichomes appendages both non-glandular and glandular was identified. Significant variation was found in both quantitative and qualitative traits, including unique ornamentation on the trichomes. The taxonomic key was constructed for accurate identification using qualitative morpho-structural traits. The outcomes of this research explored taxonomically to accurately identify the Lamiaceous species using anatomical characters. This study will provide provides the ecological adaptation linked to evolutionary traits of leaf surfaces that evolve with time to adapt the harsh environmental conditions. RESEARCH HIGHLIGHTS: Investigated foliar anatomical traits of 19 Lamiaceous species The anatomy and antimicrobial activity of essential oil yielding Lamiaceae species. SEM revealed diverse aspects including peculiar sculptured trichomes Microscopic identification of different stomatal complex.

Foliar micromorphology of selected medicinal Lamiaceae taxa and their taxonomic implication using scanning electron microscopy

In this research, 25 medicinally used Lamiaceae species belonging to 20 genera have been studied and identified for the nine disorders. We used scanning electron microscopy (SEM) for qualitative and quantitative morphological character identification. The micromorphological characters observed here were important for distinguishing the studied taxa. The highest medicinal values were reported for Vitex negundo and Scutellaria baicalensis for all considered categories except urinary and otorhinolaryngology disorders. The foliar epidermal anatomical characteristics revealed that the micromorphological features of the Lamiaceae species provide taxonomically significant and accurate identification information to delimitate the family species. Moreover, we focused on both qualitative (epidermal cell shape, stomata type, stomatal pore shape, subsidiary cell shape, glandular trichomes, and non-glandular trichome shape) as well as quantitative features (epidermal cell size, stomata size, stomatal pore size, subsidiary cell size, and trichomes size). The trichomes diversity was different in most species' on adaxial and abaxial surfaces. In most species, anomocytic stomata were observed, but other types such as diacytic, paracytic, and tetracytic type stomata were also examined. The diverse pattern of anatomical characters suggests that the studied taxa provide insight evidence for the taxonomic observation of the Traditional Chinese Medicinal plants from the Lamiaceae. This work sets an avenue for future research and taxonomic exploration of medicinal flora through microscopic investigations.

Light and scanning electron microscopy observations on morphological diversity of Rosaceae stigma and its taxonomic significance

The stigma morphology can provide a reference for exploring plant systematics and pollination biology. In this study, we observed the stigma morphological characteristics of Rosaceae in Beijing urban area in detail using light microscopy and scanning electron microscopy. The stigma of Rosaceae is entire or bilobed and mostly baculate, crateriform, cristate, discoid, or flattened. The stigma surface may have irregular, strongly raised ridges; or flat without papillae; or composed of densely or loosely arranged papillary cells. Surface ornamentation includes fossulate, psilate, psilate-striate, rugulate, scabrate, striate, and striate-rugulate. There are similarities in stigma morphology among genera and differences in stigma morphology among species within genera. The stigma shape supports the view of molecular systematic classification, that is, the former subfamilies Maloideae, Prunoideae, and Spiraeoideae are grouped into subfamily Amygdaloideae.

The morphology of stigma of Asteraceae observed by scanning electron microscopy

The morphology of stigma has taxonomic values. To further explore the taxonomy of family Asteraceae, the morphological characteristics of stigma of 28 genera, 32 species, and two varieties in the family were observed using scanning electron microscopy. The results indicated that the stigma morphology of these Asteraceae plants could be divided into 10 types, of which eight are reported for the first time. The morphological characteristics of stigma support the close relationship between genera Aster and Erigeron and among genera Sonchus, Taraxacum, and Youngia. Our results enriched the stigma type diversity data and provided a morphological basis for the study of the phylogenetic evolution of Asteraceae.

Authentication of the therapeutic Lamiaceae taxa by using pollen traits observed under scanning electron microscopy

Herbal medicines are gaining popularity worldwide for human healthcare because of their therapeutic potential. However, adulteration and use of unauthentic raw herbals as substitutes have become a major issue for the local communities and industry for reasons of safety and efficacy. Therefore, the authentication of medicinal plants before their use in herbal medicines is a need of time. Hence, the present study was designed with an aim, to authenticate the therapeutic Lamiaceous taxa by using pollen traits observed under scanning electron microscopy. Pollen micro-morphological studies solve the problem through discrimination and correct identification of the Lamiaceae species from the adulterants. Based on pollen features, Lamiaceae were further divided into two sub-families Lamioideae (tricolpate) and Nepetoideae (hexa-colpate). The pollen grains of Lamioideae were found as small to medium-sized, tricolpate, radially/bilateral symmetrical, sub-spheroidal and oblate shape. Besides, exine patterns bireticulate, reticulate and micro-reticulate, colpus surface sculpturing as psilate, gemmate, scabrate, and verrucate have also been reported. A significant variation was found in the pattern of the reticulum, thickness, and the number of secondary lumina per primary lumen. Similarly, Nepetoideae has a hexa zono-colpate pollen but tri and tetra zono-colpate pollen have also been observed. Hence, this study contributes to the authentication and correct identification of medicinally important Lamiaceae taxa by using scanning electron microscopic techniques and can help to solve the adulteration problem. Highlights Authentication of medicinally important Lamiceous taxa was carried out through scanning electron microscopic techniques. Chemotaxonomic characterization was used for the accurate identification of the therapeutic taxa. The medicinal, palynological and phytochemical significance of Lamiaceae taxa were evaluated. A significant variation was seen in the palynological traits that help in the determination and authentication of the therapeutic Lamiaceous species. Based on the chemotaxonomic characterization, our study can help to solve the adulteration problem for the reason of safety and efficacy.

SEM observations on the vegetative plant parts of Acantholimon riyatguelii Yıldırım (Plumbaginaceae), a local endemic restricted to gypsum habitats

Acantholimon riyatguelii Yıldırım is a local endemic restricted to gypsum habitats. SEM observation on roots, stems and leaves of A. riyatguelii presented detailed information of ultrastructural properties which described this species adaptations to specific conditions of gypsum habitats. This study showed that A. riyatguelii leaves which are amphistomatic exhibited strong xeromorphic adaptations reflecting numerous stomata, surface hairs, thick cuticle (∼10 µm) and advanced palisade. The xeromorphic stomata in the leaves of the A. riyatguelii growing in aridty areas are in the form of deep cavities under the epidermis. Mesophyll cells had a somewhat rounded shape and placed rather regularly in the mesophyll. Some crystal deposits were observed at stomata and inside the mesophyll cells. In the root, xylem was in the form of pentarch along with the phloem observed among the protoxylems and the periderm was ca. 100 µm thick. In the stem, the centre of the stem was filled with large xylem vessels and five bundles of phloem tissue distributed around the xylem. The ultrastructural properties of A. riyatguelii, a gypsophyte species, were given for the first time in this study at Turkey and revealed detailed descriptive ultrastructures which could serve as a source of information and reference. Finally, this study offers new and interesting avenues to interpret ultrastructural features that allow gypsophiles to tolerate drought and atypical mineral soils.

Chemometric-Guided Approaches for Profiling and Authenticating Botanical Materials

Botanical supplements with broad traditional and medicinal uses represent an area of growing importance for American health management; 25% of U.S. adults use dietary supplements daily and collectively spent over $9. 5 billion in 2019 in herbal and botanical supplements alone. To understand how natural products benefit human health and determine potential safety concerns, careful in vitro, in vivo, and clinical studies are required. However, botanicals are innately complex systems, with complicated compositions that defy many standard analytical approaches and fluctuate based upon a plethora of factors, including genetics, growth conditions, and harvesting/processing procedures. Robust studies rely upon accurate identification of the plant material, and botanicals' increasing economic and health importance demand reproducible sourcing, as well as assessment of contamination or adulteration. These quality control needs for botanical products remain a significant problem plaguing researchers in academia as well as the supplement industry, thus posing a risk to consumers and possibly rendering clinical data irreproducible and/or irrelevant. Chemometric approaches that analyze the small molecule composition of materials provide a reliable and high-throughput avenue for botanical authentication. This review emphasizes the need for consistent material and provides insight into the roles of various modern chemometric analyses in evaluating and authenticating botanicals, focusing on advanced methodologies, including targeted and untargeted metabolite analysis, as well as the role of multivariate statistical modeling and machine learning in phytochemical characterization. Furthermore, we will discuss how chemometric approaches can be integrated with orthogonal techniques to provide a more robust approach to authentication, and provide directions for future research.

Taxonomic investigation of selected rust fungi using scanning electron microscopy from Khyber Pakhtunkhwa, Pakistan

Rusts comprises the largest natural group of plant pathogens including approximately 8% of all described Fungi. Rust fungi are extremely plant pathogens responsible for great losses to agriculture productivity. Rust species belong to several genera among which more than half are Puccinia species. In Pakistan, rust causes severe damage to agriculture crops. Current study was carried out to identify and characterize different rust species common in the research area through microscopy and Scanning electron microscopy (SEM) in Khyber Pakhtunkhwa, Pakistan. Morpho-anatomical investigation of each collected rust species was carried out using different standard protocols. The dimensions of spores were measured and snapped under a stereomicroscope. SEM was used to examine the shape, size, and ornamentation of the spores of each rust fungus. Results revealed documentation of seven rust fungi, that is, Melampsora euphorbiae, Phragmidium barclayi, Puccinia nepalensis, P. exhausta, P. menthae, Uromyces capitatus, and Uromyces decorates belong to four different genera, were recorded. SEM revealed that spermogonia and Aecia were missing in most of the rust fungus studied. Uredinia was found in a scattered, irregular, lengthy, and epidermis-enclosed form. Urediniospores were found to be ovulating, elongated, echinulate, globose to sub-globose, ellipsoid to ovoid, and globose to sub-globose. Telia was found as sub-epidermal, amphigenous, dispersed, minute, and spherical cells. Teliospores ranged in form from cylindrical to oblong. The germ pores were detected in both apical (top cell) and basal (bottom cell) idiosyncratic and pedicel-attached cells. The techniques used in the current investigation will aid mycologists in rust identification and microscopic characterization.

Micromorphological characters variation of lemma and palea in subtribe of Loliinae (Poaceae)

The subtribe Loliinae is one of the largest subtribes of Poeae with about 600 species. Festuca is a large genus with close relations to other genera as Lolium, Castellia, and Vulpia. The taxonomic history of the Festuca-Lolium species group is very complicated. The polyploidy and hybridization make it more confusing. Due to the morphological similarities between genera identification is very difficult, the aim of the present study is to provide the taxonomic characters for the delimitation of the taxa of subtribe Loliinae. We used scanning electron microscopy (SEM) techniques for the evaluation of the lemma and palea surface micromorphology for 33 species of this subtribe. Multivariate statistical analysis was used to show the species groupings. Factor analysis based on the principal component analysis showed the diagnostic importance of each of the characters. The lemma and palea epidermal patterns of Castellia, Festuca, and Lolium were examined, and results revealed that Lolium and Vulpia sensu lato species made separate groups nested in the Festuca clusters. The length of the long cell of the lemma, prickle in the lemma and palea, the wall shape of long cells of the lemma, wax type, silica bodies of lemma and palea, and the short cells in palea were important diagnostic characters for the species studied. The measured and evaluated set of lemma and palea micromorphological features was unable to provide the delimitation of the Festuca genus as subgeneric or sectional level. Present observations illustrated a heterogeneous assemblage as Festuca that needs further study for delimitation.

Micromorphological considerations on Alyssum nezaketiae Aytaç & H. Duman (Brassicaceae), endemic to gypsum habitats from Turkey: An electron microscopic study

Alyssum nezaketiae is a local endemic species in gypsum habitats of Çankırı province in Turkey. In this study, I used field collected specimens of A. nezaketiae in a scanning electron microscopy examination of vegetative and reproductive structures of A. nezaketiae. The objective of the study was to investigate the micromorphological properties that define the species and that represent its adaptation(s) to the extreme environmental conditions posed by gypsum habitats. The epidermis had one to two rows at transverse sections of leaf and stem. Cortex was composed six to eight rows parenchyma cells at stem. A number of adaptations to xeric habitats were observed, including: dense silvery lepidote hairs on leaves and stems, small leaves, stomata on the lower surfaces of the leaves occurring in stomatal crypts, intense lignification in the central cylinder of the stems, and bundles of sclerenchyma in the pith region of stems. These can be interpreted as gypsophytic characteristics associated with physiological drought. Micromorphological properties of plant parts are discussed in relation to environmental conditions and possible constraint factors occurring in these gypsum habitats. Furthermore, these micromorphological studies contribute important taxonomic characters that are needed to help identify a species whose habitat is under threat from a variety of human activities.

Seed morphometry and ultrastructure studies on some Turkish orchids (Orchidaceae)

Orchid seeds have great morphological variations that imply the phylogenetic relationship of the species depending on the biodiversity of the family or act as an adaptation to seed dispersal mechanisms depending on the life form. This study aims to both describe and analyse the qualitative and quantitative traits of 12 Turkish orchids representing epidendroids and orchidoids in detail to investigate which properties are diagnostic among these taxa and also reveal if seed properties are differentiated in relationship to the ecological preferences of the studied species. Both qualitative and quantitative features were determined, and measurements were obtained using light and scanning electron microscopy. We applied the unweighted pair group method with arithmetic mean (UPGMA) cluster analysis and canonical discriminant analysis to the qualitative and quantitative traits. Furthermore, we analyzed the same orchid seed in correlation with ecological traits such as habitats and the elevation preferences of species. This study confirmed the usefulness of both data sets for effectively assessing the variation of orchid seeds. Although the seed characters such as the cell shape differences in the chalazal or medial region, seed sizes, cell numbers on the longitudinal axis, and periclinal wall ornamentation are taxonomically conserved, some other characteristics such as seed shape, the absence of periclinal wall ornamentation, and larger embryo size imply ecological adaptation or developmental achievement for germination. This study confirms the diagnostic value of both qualitative and quantitative seed features, which are effective in explaining the orchid seed variety.

The impact of seed micromorphology in the subgeneric classification of the genus Reseda L. (Resedaceae) in Turkey

Seed micromorphology of 18 taxa belonging to the genus Reseda (Resedaceae) in Turkey were investigated with scanning electron microscopy (SEM), in order to understand and check its diagnostic significance at subgeneric and sectional level. Seeds of Reseda species were photographed to evaluate different characteristics including appearance of the seed, testa ornamentation and the existence of carunculoid tissue at hilum regions. In addition, cluster analysis and principal component analysis (PCA) were performed to test whether the micromorphological data of the related taxa is compatible with the current classification of the genus. According to seed micromorphology, Reseda taxa in Turkey are divided into four main groups particularly by testa ornamentation as papillose, rugose, rugulose, and smooth. These results are also in agreement with the sectional classification of the genus in morphological and molecular perspective. The tree topology of Unweighted Pair Group Method with Arithmetic Average based on seed features supported the traditional classification. Principle component analysis revealed testa surface ornamentation as the most distinctive character for species identification. PCA also confirms our cluster grouping of the subgeneric and sectional classification of the taxa in Turkey. An identification key for the genus Reseda in Turkey is provided in the light of current data. The seed data is helpful for the identification of the genus Reseda in Turkey at sectional level. However, for an accurate identification at specific level, seed micromorphology is not sufficient alone and must be evaluated together with all diagnostic morphological features.

Palynological characteristics of selected Lamioideae taxa and its taxonomic significance

Lamioideae comprised the second-largest subfamily in Lamiaceae. Although considerable progress has recently been made in the taxonomic study of Lamioideae, the subfamily remains one of the most poorly investigated subfamily in Lamiaceae. Therefore, the present study was designed with the aim to document the pollen micromorphology of some selected Lamioideae taxa and its taxonomic significance from Pakistan. Pollen micromorphological features were observed using scanning electron microscopy. The pollen grains are monad, tricolpate, radially/bilateral symmetrical. The pollen grains were small to medium-sized having oblate, oblate/subspheroidal, and subspheroidal shape. Exine sculpturing was observed as reticulate, microreticulate, and bireticulate. The colpus surface ornamentation was found as verrucate, gemmate, scabrate, and psilate. There was a considerable variation between the species in the micromorphology, that is, the coarseness of the reticulum, thickness of the muri comprising the reticulum and the number of secondary lumina per primary lumen. Hence, this study documented the pollen morphology of some selected taxa of the subfamily Lamioideae from Pakistan and strengthens the taxonomic identification of subfamily based on pollen characters, which helps in the correct identification, discrimination of the species of Lamioideae at generic and species level.

Foliar micromorphology and its role in identification of the Apocynaceae taxa

In the present study, we evaluate the importance of foliar epidermal micromorphological characteristics of Apocyanaceae for accurate identification and classification. The species were collected from the University of Peshawar's main campus in the spring season to observe its qualitative and quantitative features. The length and width of guard cells, stomatal pore and subsidiary cells, trichomes, and crypts on both sides of the leaf were examined. Many species were observed to be hypostomatic. Plumeria rubra, Raulfia serpentine, Thevetia peruviana, Trachelospermum lucidum, Alstonia scholaris, and Catharanthus roseus demonstrated hypostomatic leaves. Nearly all the investigated species had anisocytic type of stomata only or in combination with other types of stomata on the upper and lower epidermis. Carissa carandas had anomocytic, anisocytic, and cyclocytic type of stomata on the upper epidermis, and the lower epidermis showed variations in stomatal type, such as anomocytic, stephanocytic, brachyparacytic, and hemiparacytic. Nerium oleander had no specific shape of stomata but showed stomatal crypts in which the stomata were enclosed inside many trichomes. The taxonomic key based on stomatal types, epidermal cells, stomatal index value, and statistical analysis, along with the variations in the epidermal cells, shows the link between the selected plants species, which will provide a baseline for future anatomical studies. This study highlights many undocumented micromorphological characteristics. The anatomical characteristics observed in this study will be helpful for taxonomic identification and species delimitation of the family Apocynaceae.

Feasible regeneration and agro bacterium-mediated transformation of Brassica juncea with Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) gene

In the present study an effort has been made to optimize the in vitro regeneration protocol for Agrobacterium-mediated transformation of Brassica juncea, because of its importance as oilseed crops. The highest callus induction frequency of 87% was observed on MS (Murashige and Skoog, 1962) medium supplemented with 4 µM 6-benzyladenine (BA) after four weeks of culture period. Subculturing of organogenic calli in MS media with a similar hormonal composition resulted in shoot organogenesis after six weeks of culture cultivation. The highest shoot induction frequency (92%) was recorded on MS medium containing 4 µM BA in combination with 1 µM of α-naphthalene acetic acid (NAA). Further, well-developed roots were formed in MS media augmented with 6 µM of Indole acetic acid (IAA) in combination with 1 µM Kinetin (Kn). Cotyledon explants were exploited in vitro for the successful transformation of B. juncea. A binary vector comprised of the Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) gene under the transcriptional control of a glycinin promoter and with a basta selection marker was introduced into A. tumefaciens strain GV3101 via electroporation. EaDAcT gene is responsible for unusual triacylglycerol’s production where the sn-3 position is esterified with acetate instead of the long-chain fatty acid found in the triacylglycerol’s. The highest regeneration frequency (100%) of transgenic shoots was observed on MS medium supplemented with 4 µM BA plus 1 µM NAA in the presence of 25 mg l⁻¹ basta and 160 mg l⁻¹ timintin. The efficiency of stable transformation was found to be approximately 7% in the transgenic plants. Moreover, the transformed regenerated shoots were confirmed by PCR analysis using EaDAcT gene-specific primers.

Neuropharmacological potential of various morphological parts of Camellia sinensis L

Camellia sinensis L. has long been used as a therapeutic agent for the Central nervous system (CNS) due to the presence of flavonoids. The present study aimed to evaluate the dose-dependent Neuropharmacological behavioral potential of Camellia sinensis seed and leaf extracts on mice. To evaluate the differential potential of leaf and seed extract various doses were prepared and examined in open field, head dip, rearing, cage cross, swimming and traction tests. One-way ANOVA set at P* < 0.05 followed by POST HOC LSD (P* < 0.01) was applied to evaluate the significant difference among the treatments. Herein both seed and leaf extract showed significant results at high doses. Interestingly leaf extract at high dose showed significant effect on mice CNS in open field and head dip test, while seed at high dose revealed significant stimulus on mice CNS in rearing, cage cross, swimming and traction tests. Overall results showed that seed produced more stimulant effect and less calmness as compared to leaf extract was. Tea leaves had already known as potential CNS stimulant drugs; current investigation suggests that tea seed can be used as an alternative CNS stimulant agent with more effective stimulant action.