Morpho-anatomical studies of family lamiaceae species of district Lahore, Punjab: a revision to flora of Pakistan.

BACKGROUND: This study was aimed to determine the taxonomic position and delimitation of fifteen Lamiaceae taxa using leaf epidermal morpho-anatomical features in Lahore. A main objective of the study was also the revision and upgradation of Lamiaceae taxa in the flora of Pakistan, as no details of studied species are found in the flora of Pakistan. METHODS: The examination of significant anatomical parameters, such as epidermal cell shape and size, stomatal types, guard and subsidiary cells shape and size, stomatal cavity size, trichome size and shape, oil droplets, crystals, and secretory cavity characteristics were studied using light microscopic (LM) and scanning electron microscopic (SEM) techniques. Among all the studied Lamiaceae species, these anatomical features varied significantly. Principal component analysis and correlation were done to distinguish the species' similarities. RESULTS: Most species had pentagonal and hexagonal epidermal cells with straight anticlinal wall thickness. On the adaxial surface, paracytic stomata were found in Ocimum basilicum L. and Rosmarinus officinalis L. Diacytic stomata was observed in Ajuga reptans L. and anisocytic stomata in Galeopsis tetrahit L. In the abaxial surface, trichomes were present in five species, i.e., Mentha suaveolens Ehrh. A. reptans, Thymus vulgaris L., M. haplocalyx, and Salvia splendens Ewat. In S. splendens, peltate and glandular trichomes were seen whereas, in other species, trichomes were long, unbranched glandular and had tapering ends. In adaxial side trichomes were present only in M. suaveolens, A. reptans, S. bazyntina, O. basciculum, S. splendens, S. officinalis, S. rosemarinus. In other species, trichomes were absent on the adaxial surface. In abaxial view, M. suaveolens had the largest length of trichomes, and O. basciculum had the smallest. S. splendens L. had the largest trichome width, while T. vulgaris had the smallest. CONCLUSION: Hence, according to these findings, morpho-anatomical traits are useful for identifying Lamiaceae taxa. Also, there is a need of upgradation and addition of studied taxa in flora of Pakistan comprehensively.

Anatomical features of ecological importance and taxonomic value revealed by scanning electron microscopy and light microscopy in Camonea umbellata (L.) A.R. Simões & Staples (Convolvulaceae).

This article describes detailed and novel data on the anatomy and histochemistry of leaves, stems, and roots of Camonea umbellata (L.) A.R.Simões & Staples in different environments for the identification of characters with taxonomical value and of ecological importance, with provision of light and scanning electron microscopy images. To analyze the characters, we collected samples of the vegetative organs of three individuals in each of three populations, which were in a grazing area, an urban environment, and a biological reserve. The main diagnostic anatomical markers for the identification of C. umbellata include amphistomatic leaves, tetracytic and brachyparatetracytic stomata, peltate trichomes, long simple trichomes, epidermis with striated cuticle ornamentation, mesophyll with acute borders, presence of druses, secretory channels, angular collenchyma, fibrous pericycle in the stem, intraxylary phloem in the vegetative organs, oil bodies throughout the midrib, petiole, stem and root, and epicuticular waxes of the crust and coiled rodlet types. Since the characters above did not show variation in the environments evaluated, we consider these characters taxonomically useful for the identification of C. umbellata. RESEARCH HIGHLIGHTS: The anatomy of the aerial vegetative organs of Camonnea umbellata retains common Convolvulaceae characters. The sinuosity of the epidermal cell walls and the density of trichomes in the epidermis of the petiole were visually variable characters among the analyzed individuals. Amphistomatic leaves, tetracytic and brachyparatetracytic stomata, peltate trichomes, epidermis with striated cuticle ornamentation, dorsiventral mesophyll with border acute, presence of druses, secretory structures, angular collenchyma, fibrous pericycle in the stem, intraxillary phloem, presence of oil bodies in all organs, and epicuticular waxes of the crust type and coiled rods were considered important anatomical markers for the recognition and correct identification of Camonea umbellata.

Endemic species analysis: Foliar epidermal anatomical characters of Aster glehnii F. Schmidt (Asteraceae).

The classification and identification of Aster glehnii F. Schmidt are determined from its foliar epidermal anatomical features. Scanning electronic microscopy has been used to determine the foliar epidermal anatomical characteristics of the species in detail. This study compared the qualitative and quantitative characteristics of the leaf epidermis of A. glehnii for taxonomic identification to be used as a reference for future studies on the species. A. glehnii has smooth, thin cuticles, depressed anomocytic stomata dispersed randomly throughout the leaf surface, polygonal epidermal cells with straight to slightly curved anticlinal walls, and no trichomes. There are obvious veins containing thick-walled bundle sheath cells. The stomatal density is between 100 and 150 stomata per millimeter. The vein density ranges from five to 10 veins per millimeter, and the epidermal cells are 10 to 20 µm long and 5 to 10 µm in width. Understanding the connections between the different A. glehnii species and categorizing and identifying them depend heavily on these foliar epidermal structural features. Taxonomy and conservation are closely intertwined because the former serves as the basis for comprehending and safeguarding biodiversity. RESEARCH HIGHLIGHTS: Optical microscopy of the A. glehnii leaf epidermis for taxonomic identification SEM was used to identify and authenticate endemic species Microscopic identification of endemic species can assist in the conservation.

Living jewels: iterative evolution of iridescent blue leaves from helicoidal cell walls.

BACKGROUND AND AIMS: Structural colour is responsible for the remarkable metallic blue colour seen in the leaves of several plants. Species belonging to only ten genera have been investigated to date, revealing four photonic structures responsible for structurally coloured leaves. One of these is the helicoidal cell wall, known to create structural colour in the leaf cells of five taxa. Here we investigate a broad selection of land plants to understand the phylogenetic distribution of this photonic structure in leaves. METHODS: We identified helicoidal structures in the leaf epidermal cells of 19 species using transmission electron microscopy. Pitch measurements of the helicoids were compared with the reflectance spectra of circularly polarized light from the cells to confirm the structure-colour relationship. RESULTS: By incorporating species examined with a polarizing filter, our results increase the number of taxa with photonic helicoidal cell walls to species belonging to at least 35 genera. These include 19 monocot genera, from the orders Asparagales (Orchidaceae) and Poales (Cyperaceae, Eriocaulaceae, Rapateaceae) and 16 fern genera, from the orders Marattiales (Marattiaceae), Schizaeales (Anemiaceae) and Polypodiales (Blechnaceae, Dryopteridaceae, Lomariopsidaceae, Polypodiaceae, Pteridaceae, Tectariaceae). CONCLUSIONS: Our investigation adds considerably to the recorded diversity of plants with structurally coloured leaves. The iterative evolution of photonic helicoidal walls has resulted in a broad phylogenetic distribution, centred on ferns and monocots. We speculate that the primary function of the helicoidal wall is to provide strength and support, so structural colour could have evolved as a potentially beneficial chance function of this structure.

Structure, ultrastructure and cation accumulation in quinoa epidermal bladder cell complex under high saline stress.

Quinoa is a facultative halophyte with excellent tolerance to salinity. In this study, the epidermal bladder cell complex (EBCc) of quinoa leaves was studied to determine their cellular characteristics and involvement in salt tolerance. We used light microscopy, confocal RAMAN microscopy, confocal fluorescence microscopy, transmission electron microscopy, and environmental scanning electron microscopy complemented by energy dispersive X-ray analysis. Ionic content was quantified with flame atomic absorption spectroscopy and with flame emission photometry. Results show that: (i) the number of EBCcs remains constant but their density and area vary with leaf age; (ii) stalk cells store lipids and exhibit thick walls, bladder cells present carotenes in small vesicles, oxalate crystals in vacuoles and lignin in their walls and both stalk and bladder cells have cuticles that differ in wax and cutin content; (iii) chloroplasts containing starch can be found on both stalk and bladder cells, and the latter also presents grana; (iv) plasmodesmata are observed between the stalk cell and the bladder cell, and between the epidermal cell and the stalk cell, and ectodesmata-like structures are observed on the bladder cell. Under high salinity conditions, (v) there is a clear tendency to accumulate greater amounts of K+ with respect to Na+ in the bladder cell; (vi) stalk cells accumulate similar amounts of K+ and Na+; (vii) Na+ accumulates mainly in the medullary parenchyma of the stem. These results add knowledge about the structure, content, and role of EBCc under salt stress, and surprisingly present the parenchyma of the stem as the main area of Na+ accumulation.

Comparative microscopic investigations of leaf epidermis in four Ajuga species from Korea.

The genus Ajuga is widely distributed in temperate to subtropical regions, and four species are currently recognized in Korea (A. decumbens, A. multiflora, A. nipponensis, and A. spectabilis), but epidermal anatomical differences across these species have never been described. A comparative study of the leaf micromorphological characteristics of Korean Ajuga species was performed using light microscopy (LM) and scanning electron microscopy (SEM) to elucidate their taxonomic usefulness and to assess leaf micromorphological diversity. Considerable diversity in epidermal and stomatal anatomy was observed across Korean Ajuga species. Species had both hypostomatic or amphistomatic leaves, with anomocytic, anisocytic, diactyic, or actinocytic stomatal complexes. Guard cell length across species ranged from 17.66 ± 0.57 µm to 32.50 ± 2.38 µm and correlated with genome size. Abnormal stomata were frequently observed in three species (A. decumbens, A. multiflora, and A. nipponensis) but not in A. spectabilis. Three types of glandular trichomes were found: peltate in all species, short-stalked in all species, and long-stalked glandular trichomes in A. multiflora. Among the investigated leaf micromophological characters, trichome type, epidermal cell shape, and stomatal morphology were all taxonomically informative traits at a species level. RESEARCH HIGHLIGHTS: A comprehensive micromorphological description of the leaf surface is provided for Korean Ajuga species using scanning electron microscopic (SEM) and light microscopic (LM) analyses. The diverse range of stomatal development and the occurrence of polymorphic stomatal types are documented for the first time in Korean Ajuga species. The great diversity in stomatal and trichome morphology in Korean Ajuga species are taxonomically useful traits for species identification.

Comparative analysis of foliar epidermal anatomical traits and their taxonomic relevance in Lilium pumilum, L. brownii, and L. davidi.

The anatomical traits of plant species are essential for taxonomic analyses and evolutionary evaluations. Clarifying the anatomical characteristics of the foliar epidermis in three distinct Lilium species L. pumilum Delile, L. brownii F.E.Br. ex Miellez and L. davidii Duch. ex Elwes were studied in this article. The objective is to assess the taxonomic relevance of these characteristics and their potential as indicators of species divergence within the genus Lilium. Plant samples were gathered in Gansu, China, from numerous populations of each species that represented a range of climatic and ecological factors. A microscopic analysis employing thin slices and peel mounts was done to assess the stomatal density and dimensions. Significant interpopulation differences in stomatal features were found in the results, offering potential opportunities for taxonomic discrimination. The species differ in qualitative and quantitative characters to differentiate the three species. The links between the observed anatomical characteristics and species classification within the Lilium genus were clarified for the three studied species. In the end, this research advances knowledge of Lilium taxonomy, aids in conservation efforts, and deepens awareness of the general patterns of plant variety. RESEARCH HIGHLIGHTS: Epidermal Traits Aid Taxonomy: Cell shape, arrangement, and structures aid Lilium Identification. Cuticle Reveals Taxonomic Clues: Thickness, composition, and structure inform classification. Micromorphology for Species ID: Cell shape, wax, and striations differentiate Lilium species.

Investigations on the morpho-anatomy and histochemistry of Aconitum napellus L.

Aconitum napellus L. is a popular medicinal plant extensively used in homeopathy. This article provides detailed morphology and microscopy, including the anatomical and histochemical features of the herb, to aid authentication and quality control. In cross-section, the root in secondary growth shows the phloem surrounded by pericyclic fibers and a well-developed xylem. The stem is irregular in outline, displaying unicellular trichomes and many free collateral vascular bundles encircling the pith. The leaf is dorsiventral, hypostomatic with anomocytic and anisocytic stomata, and shows non-glandular trichomes. The floral parts are characterized by uniseriate epidermises, homogeneous mesophyll, anomocytic stomata on the abaxial surface, trichomes, and oval pollen grains. The tissue fragments in powdered herbs show these characteristics and have numerous starch grains with thimble-shaped, linear or star-shaped hilum. The detailed macroscopic and microscopic analysis provided in this study can help in the authentication and quality control of A. napellus raw materials. RESEARCH HIGHLIGHTS: Key anatomical, micromorphological, and microchemical features of Aconitum napellus are described. The results of the study can support the taxonomy of the genus Aconitum. Morphological standardization of the species reported here is helpful in the quality control of this herb.

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. RESEARCH HIGHLIGHTS: This research offers a thorough microscopic identification of the family Lamiaceae. Taxonomic information on the trichome characters and types for the accurate authentication. Qualitative and quantitative characterization of 25 medicinally used Lamiaceae taxa.

Palyno-anatomical characters and their systematic significance in the family Apiaceae from Chitral, eastern Hindu Kush, Pakistan.

The present study was performed to provide a detailed explanation of leaf epidermal anatomy and pollen micromorphological features of selected species of family Apiaceae from Chitral, eastern Hindu Kush region as the basis of forthcoming studies. In the present article pollen morphology of eight species and foliar epidermal of seven species of family Apiaceae have been examined through microscopic techniques. In results two types of pollen prolate (five species) and perprolate (three species) with three colpi have been recorded. The exine ornamentation was found to be regulate, striate, and cerebroid. Largest pollen was found in Heracleum leucocarpum with the polar diameter of 43.25 µm and equatorial diameter of 21.6 µm. Smallest pollen was observed in Elaeosticta chitralica with the polar diameter of 18.4 µm. The P/E ratio varied from 1.59 to 2.16. Regarding to foliar epidermal anatomy, three types of epidermal cells including rectangular, irregular, and polygonal with variation in anticlinal wall pattern were determined. In the selected species three kinds of stomata comprising anisocytic, anomocytic, and paracytic type were reported in the current research. The size of epidermal cells ranged from 106 × 42.50 µm in Bupleurum falcatum subsp. cernuum and 77.25 × 26.35 µm in Prangos pabularia in adaxial surface. Largest stomatal complex was found in Prangos pabularia both in adaxial 33.55 × 20.05 µm and abaxial 50.25 × 39.40 µm. All the observed quantitative and qualitative features of the species were proved to be useful in the delimitation of species at generic and species level.

Molecular insights into the complex mechanics of plant epidermal cell walls.

Plants have evolved complex nanofibril-based cell walls to meet diverse biological and physical constraints. How strength and extensibility emerge from the nanoscale-to-mesoscale organization of growing cell walls has long been unresolved. We sought to clarify the mechanical roles of cellulose and matrix polysaccharides by developing a coarse-grained model based on polymer physics that recapitulates aspects of assembly and tensile mechanics of epidermal cell walls. Simple noncovalent binding interactions in the model generate bundled cellulose networks resembling that of primary cell walls and possessing stress-dependent elasticity, stiffening, and plasticity beyond a yield threshold. Plasticity originates from fibril-fibril sliding in aligned cellulose networks. This physical model provides quantitative insight into fundamental questions of plant mechanobiology and reveals design principles of biomaterials that combine stiffness with yielding and extensibility.

Structure, Assembly and Function of Cuticle from Mechanical Perspective with Special Focus on Perianth.

This review is devoted to the structure, assembly and function of cuticle. The topics are discussed from the mechanical perspective and whenever the data are available a special attention is paid to the cuticle of perianth organs, i.e., sepals, petals or tepals. The cuticle covering these organs is special in both its structure and function and some of these peculiarities are related to the cuticle mechanics. In particular, strengthening of the perianth surface is often provided by a folded cuticle that functionally resembles profiled plates, while on the surface of the petal epidermis of some plants, the cuticle is the only integral continuous layer. The perianth cuticle is distinguished also by those aspects of its mechanics and development that need further studies. In particular, more investigations are needed to explain the formation and maintenance of cuticle folding, which is typical for the perianth epidermis, and also to elucidate the mechanical properties and behavior of the perianth cuticle in situ. Gaps in our knowledge are partly due to technical problems caused by very small thicknesses of the perianth cuticle but modern tools may help to overcome these obstacles.

Fluctuations shape plants through proprioception.

Plants constantly experience fluctuating internal and external mechanical cues, ranging from nanoscale deformation of wall components, cell growth variability, nutating stems, and fluttering leaves to stem flexion under tree weight and wind drag. Developing plants use such fluctuations to monitor and channel their own shape and growth through a form of proprioception. Fluctuations in mechanical cues may also be actively enhanced, producing oscillating behaviors in tissues. For example, proprioception through leaf nastic movements may promote organ flattening. We propose that fluctuation-enhanced proprioception allows plant organs to sense their own shapes and behave like active materials with adaptable outputs to face variable environments, whether internal or external. Because certain shapes are more amenable to fluctuations, proprioception may also help plant shapes to reach self-organized criticality to support such adaptability.

Three-dimensional reconstruction and comparison of vacuolar membranes in response to viral infection.

The vacuole is a unique plant organelle that plays an important role in maintaining cellular homeostasis under various environmental stress conditions. However, the effects of biotic stress on vacuole structure has not been examined using three-dimensional (3D) visualization. Here, we performed 3D electron tomography to compare the ultrastructural changes in the vacuole during infection with different viruses. The 3D models revealed that vacuoles are remodeled in cells infected with cucumber mosaic virus (CMV) or tobacco necrosis virus A Chinese isolate (TNV-AC ), resulting in the formation of spherules at the periphery of the vacuole. These spherules contain neck-like channels that connect their interior with the cytosol. Confocal microscopy of CMV replication proteins 1a and 2a and TNV-AC auxiliary replication protein p23 showed that all of these proteins localize to the tonoplast. Electron microscopy revealed that the expression of these replication proteins alone is sufficient to induce spherule formation on the tonoplast, suggesting that these proteins play prominent roles in inducing vacuolar membrane remodeling. This is the first report of the 3D structures of viral replication factories built on the tonoplasts. These findings contribute to our understanding of vacuole biogenesis under normal conditions and during assembly of plant (+) RNA virus replication complexes.

Atomic Force Microscopy to Study Cell Wall Mechanics in Plants.

Atomic force microscopy (AFM) is an indentation technique used to reconstruct the topography of various materials and organisms. AFM can also measure the mechanical properties of the sample. In plants, AFM is applied to image cell wall structural details and measure the elastic properties in the outer cell walls. Here, I describe the use of high-resolution AFM to measure the elasticity of resin-embedded ultrathin sections of leaf epidermal cell walls. This approach allows to access the fine details within the wall matrix and eliminate the influence of the topography or the turgor on mechanical measurements. In this chapter, the sample preparation, AFM image acquisition, and processing of force curves are described. Altogether, these methods allow to measure the wall stiffness and compare different cell wall regions.

Comparative Analyses of the Self-Sealing Mechanisms in Leaves of Delosperma cooperi and Delosperma ecklonis (Aizoaceae).

Within the Aizoaceae, the genus Delosperma exhibits a vast diversification colonizing various ecological niches in South-Africa and showing evolutionary adaptations to dry habitats that might include rapid self-sealing. Leaves of Delosperma react to external damage by the bending or contraction of the entire leaf until wound edges are brought into contact. A study of leaf morphology and anatomy, biomechanics of entire leaves and individual tissues and self-sealing kinematics after a ring incision under low and high relative humidity (RH) was carried out comparing the closely related species Delosperma cooperi and Delosperma ecklonis, which are indigenous to semi-arid highlands and regions with an oceanic climate, respectively. For both species, the absolute contractions of the examined leaf segments ("apex", "incision", "base") were more pronounced at low RH levels. Independent of the given RH level, the absolute contractions within the incision region of D. cooperi were significantly higher than in all other segments of this species and of D. ecklonis. The more pronounced contraction of D. cooperi leaves was linked mainly to the elastic properties of the central vascular strand, which is approximately twice as flexible as that of D. ecklonis leaves.

High-Resolution Imaging of Cellulose Organization in Cell Walls by Field Emission Scanning Electron Microscopy.

Field emission scanning electron microscopy (FESEM) is a powerful tool for analyzing surface structures of biological and nonbiological samples. However, when it is used to study fine structures of nanometer-sized microfibrils of epidermal cell walls, one often encounters tremendous challenges to acquire clear and undistorted images because of two major issues: (1) Preparation of samples suitable for high resolution imaging; due to the delicateness of some plant materials, such as onion epidermal cell walls, many things can happen during sample processing, which subsequently result in damaged samples or introduce artifacts. (2) Difficulties to acquire clear images of samples which are electron-beam sensitive and prone to charging artifacts at magnifications over 100,000×. In this chapter we described detailed procedures for sample preparation and conditions for high-resolution FESEM imaging of onion epidermal cell walls. The methods can be readily adapted for other wall materials.

Scanning electron microscopic screening of 20 medicinally important Asteroideae taxa.

In the present study anatomical characterization of 20 medicinally important Asteroideae species were done under light and scanning electron microscopy. Variety of qualitative and quantitative anatomical characters like epidermal cells, stomata, guard cells, subsidiary cells, trichomes and oil droplets were observed. Generally pentagonal, polygonal, irregular or hexagonal, smooth, undulating thick walled epidermal cells were observed in studied species. In abaxial surface Thymophylla tenuiloba L. possessed the largest length of epidermal cell that is, 221.6 (156.6-286.6) µm whereas Bellis perenis L. showed the smallest length that is, 46.4 (32.6-60.2) µm. Average width of epidermal cells ranged from 57 (22-92) µm to 169 (127.9-210.1) µm. Cosmos sulphureus Cav. had smallest width while Thymophylla tenuiloba L. had the largest width. In adaxial surface Artemisia absinthium L. possessed the largest length of epidermal cell that is, 269 (165.1-372.9) µm whereas Bellis perenis L. showed the smallest length that is, 61.4 (42.6-80.2) µm. Average width of epidermal cells ranged from 50.8 (32.6-69) µm to 260 (116-202) µm. Thymophylla tenuiloba L. had smallest width while Dahlia pinnata Cav. had the largest width. Among stomatal characters anisocytic, anomocytic, and diacytic stomata were observed in selected species of Asteroideae. Nonglandular uniserate, multicellular, unbranched pointed tips with bulbous base trichomes were reported in some Asteroideae members while some possessed glandular, capitates mushroom like multicellular trichomes covered with tubercle papicles. Rounded, oval, triangular shaped oil droplets were observed in some species. It is concluded that qualitative and qualitative anatomical variations in trichomes, stomata and epidermal cells are of good taxonomic value for the Asteroideae species.