Using multiple microscopic techniques for the comparative systematic of Spergula fallax and Spergula arvensis (Caryophyllaceae)

Micromorphological study of some Salsola species (Amaranthaceae) in Iran and its systematic significance using scanning electron microscopy

Using scanning electron microscopy (SEM), six Salsola species from Iran were examined for their epidermis, seed, and fruit micromorphology. Among them were S. brachiata from section Heterotricha, S dendroides, S. incanescens, and S. orientalis from section Caroxylon, S. kali from section Kali, and S. turcomanica from section Physurus. Epidermal cells are divided into three types. There were diamond, irregular, and polygonal cells, as well as straight and undulated walls. Studied species of Salsola have smooth or sculptured fruit surfaces, and there are three main types of fruit surface ornamentation. There is a significant difference between these species based on the type of hair and density of the fruit. Seed shape and color have little systematic significance. The seed epidermis is composed of polygonal, elongated polygonal, irregular, and diamond cells. Although polygonal and irregular testa cells are most common, their size and shape can provide additional information and useful diagnostic characteristics at both specific and infraspecific levels. For taxonomic separation, the current study provides novel insights at micromorphological levels. RESEARCH HIGHLIGHTS: This article reports halophyte are shown as models for adaptation to extreme habitats. These plants are placed among the ecological communities of xerophytes. Here, for the first time, the microstructural analysis of Salsola has been investigated. Additionally, it provides new insights into plant species' response to extreme conditions, as well as possible adaptation strategies at the micromorphological level.

Taxonomic significance of morphological and elemental characteristics of achenes of Artemisia genus from Turkey

In the study, the achene macromorphological and micromorphological characters of the genus Artemisia distributed in Turkey have been researched with the target of knowing systematically important carpological structures for the examined species. Macro-morphological structures of the achenes including color, shape, dimension, and carpopodium diameter were studied with 100 achenes of 10 specimens per taxa with a Light Microscope. Micro-morphological features of the achenes containing surface ornamentation, anticlinal and periclinal cell walls, epidermal cells, and the presence of secondary structures were examined with a Scanning Electron Microscope. EDS analyses were performed with a SEM. EDS analyses were carried out by selecting the same spot on the sample surface at 80 sec under 30 μm aperture size, with 20 kV acceleration voltage, 8 mm operating distance, high current, and processing time conditions. The color, shape, and dimension of achene have macro-morphologically shown variations. The examined achenes are separated into four shapes; fusiform-oblong, oblong, oblong-ovate, and ovate. Oblong-ovate is the most common type. Achene dimensions range from 0.62 to 2.48 mm in length, and from 0.30 to 1.21 mm in width. Also, carpopodium diameter varies between 0.10 and 0.19 mm. Achene surfaces of the examined taxa are micro-morphologically assessed, and substantial differences are noticeably detected on behalf of the surface structures for instance, surface ornamentation, anticlinal and periclinal cell walls, epidermal cells, and the presence of secondary structures of the achenes. Surface ornamentation is separated into 10 types: irregularly sulcate, regularly sulcate, ruminate, sulcate-scalariform, rugose, favulariate, slightly sulcate, alveolate, tuberculate, and reticulate. A percentage comparison of the elements in the achene pericarp of the studied taxa has been performed with SEM-EDS. Accordingly, pericarps in taxa include C, Ca, K, Mg, Cl, Si, Na, and S elements. In the taxonomy of the genus Artemisia, the achene morphological characters are very significant characteristics that disclose inter-specific relations among the examined taxa. Moreover, a dichotomous key is offered for the identification of the studied taxa based on achene characters. RESEARCH HIGHLIGHTS: The achenes of Turkish Artemisia taxa have been examined in depth. The morphological characteristics of achenes of Turkish Artemisia taxa have been studied using SEM and LM for the first time and debated the systematic practice of these characters. The elemental content of the achene pericarp has been systematically evaluated for the first time.

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.

Monitoring the delicate operations of surgical robots via ultra-sensitive ionic electronic skin

The arrival of surgical robots in high-end medical equipment is a landmark, and the realization of tactile sensation a major challenge in this important cutting-edge research field. Aiming to address this issue, we present ultra-sensitive ionic electronic skin in the form of flexible capacitive pressure sensors, which incorporate multistage bionic microstructures in ion gels for the purpose of monitoring the delicate operations of surgical robots. Significantly, the ionic skin exhibits an ultra-high sensitivity of 9484.3 kPa^-1 (<15 kPa), and the sensitivity remains higher than 235 kPa^-1 in the wide range of 15-155 kPa. The device has also achieved a detection limit as low as 0.12 Pa or, equivalently, 0.31 mg, fast response within 24 ms, and high robustness (loading/unloading for 5000 cycles without fatigue). The sensor facilitates the challenging task of tele-operated robotic threading, which exceeds the human tactile perception limit when threading a needle. We have also confirmed that ionic skin can be used in robot-assisted invasive surgery, such as incision/resection of tissues and suturing of wounds, providing tactile information to surgeons to improve operation success rates. The flexible ionic skin is capable of conforming to the various shapes of robotic manipulators, thus has great promise for applications in robotic dexterous manipulation, prosthetics and human-machine interfaces.

Scanning electron microscopic identification of ten novel, non-edible oil seeds for bioenergy production

Biodiesel is a sustainable, inexpensive, and alternative energy source produced from vegetable oils and animal fats. Precise and authentic identification of oil yielding plant species is very crucial. Therefore, scanning electron microscopy (SEM) was employed in our current investigation to study micromorphological characteristics of ten novel oil yielding seeds for their reliable identification. Macromorphological characters of sample seeds were explored by light microscopy. Seed size varied from 16 to 6.2 mm in length and 18.4-4.5 mm in width. Seed shape varied from ovoid to cordial and color from beige to brown. Seed oil content ranged from 25% to 45% (w/w). Whereas free fatty acid (FFA) content of seed oil varied from 0.42 to 3.4 mg KOH/g. Biodiesel potential of Chamaerops humilis was found to be highest (98%) in all. Besides, ultra-structural observation of seeds demonstrated variation in surface sculpturing which varied from rugous, reticulate, perforate, striate, and webby. Periclinal wall arrangements varied from rough, ridged, depressed, thick and curved whereas, anticlinal walls pattern showed variation from wavy, smooth, raised, deep and depressed. It was ultimately concluded that Scanning electron microscopy could serve as an advanced tool representing hidden ultra-structural characters of seeds. It offers significant knowledge to researchers and local community for their accurate and genuine identification.

Morpho-palynological and anatomical studies in desert cacti (Opuntia dillenii and Opuntia monacantha) using light and scanning electron microscopy

Opuntia is the most diverse and widely distributed drought resistant promising genus of family Cactaceae. The cladodes were utilized to quantify the chemical composition of these plants helpful in lignocellulose conversion and their application towards biofuel production. The present study was aimed to evaluate and compare the taxonomic relationship based on morphology, stem anatomy and palynology of important desert cacti including Opuntia dillenii and Opuntia monacantha. This study also evaluates the potential usefulness of morphological, anatomical and pollen traits using light and scanning electron microscopy. The obtained microcharacters of stem and flowers are considered diagnostic at the generic and specific levels. Some distinguishing morphological features observed were elliptical to obovate cladodes, 1-7 spines per areole and presence of glochidia in O. dillenii. Pollen and stem anatomical characters of the studied taxa are considered highly diagnostic at the generic and species levels. The epidermis has irregular and wavy cells, with straight to sinuate wall pattern and paracytic stomata. Pollen grains appear as pantoporate and prolate spheroidal having reticulate to perforate-reticulate sculpturing while exine semi-tectate to tectate. The taxonomic features studied could be valuable to elaborate and helpful in correctly identification of Opuntia species. The methods of diverse microscopic examination also providing sufficient evidence about the taxonomy of the Opuntia species.

Light and scanning electron microscopic observation of palynological characteristics in spineless Astragalus L. (Fabaceae) and its taxonomic significance

Palynological characterization is considered to be one of the significant taxonomic tools for the delimitation and identification of morphologically complicated taxa. Hence, the pollen morphology of 12 species of spineless Astragalus L. was examined using light and scanning electron microscopy. Studied pollen were small to medium, monad, prolate to per-prolate and tricolporate type in all studied taxa. The exine sculpturing varied from reticulate to microreticulate whereas colpus ornamentation ranged from scabrate to granulate. Furthermore, maximum polar and equatorial diameter was recorded in Astragalus leucocephalus Bunge. (45.00 μm) and A. pyrrhotrichus Boiss. (22.91 μm) while minimum in A. amherstianus Benth. ex Royle (28.75 μm) and A. amherstianus Benth. ex Royle (15.00 μm), respectively. Similarly, the ratio of polar to equatorial diameter was recorded maximum in A. ophiocarpus Boiss. (2.05). The width of colpi was larger in A. hamosus L. (1.29 μm) and smaller in A. ophiocarpus Boiss. (0.62 μm). We have also found the maximum value of mesocolpium in A. retamocarpus Boiss. (2.08 μm) while minimum in A. oxyglottis Steven ex M.Bieb. (1.87 μm). The quantitative pollen attributes helped in the development of pollen keys for the accurate and quick identification of the studied species. Furthermore, ordination and cluster analysis were performed for the differentiation of the investigated taxa at species level. Based on our results, we conclude that pollen features can be used for the delimitation and identification of the studied taxa.

Pollen morphology of selected melliferous plants and its taxonomic implications using microscopy

This research aimed to explore the melliferous bee flora pollen from arid zones of District Attock, Islamabad Capital and Rawalpindi. Morpho-palynological features has provided key information for the classification and help to explain the taxonomy of several genera and species. Therefore, in this work, we examined the morphological characters of pollen potentially to be used for the species delimitation of bee flora. A total of 18 bee floral species, classified into 12 different families were collected, pressed, identified and then acetolyized to observe the grains under microscopy. Bee pollen can be described by small, medium to large sized morphotypes presenting five types of shapes, prolate spheroidal in (seven species), sub-prolate (six species), oblate spheroidal (three species), oblate and prolate (one species each) was examined. The observed polar and equatorial diameter were found maximum in Zea mays 73.5 μm and Pelargonium inquinans 66.75 μm respectively. Pollen of six different types was found namely: tricolporate, 3-zonocolporate, monoportae, tetracolporate, tetraporate and mononsulcate. Whereas highest value of colpi length was measured in Grewia tenax (24.55 μm). Exine surface nature of pollen was examined echinate psilate and scabrate. Exine thickness noted to be maximum in Verbena tenuisecta (8.40 μm) and minimum in Citrus macrocarpa (0.4 μm). Bee floral species considered difficult to identify based on other morphological traits were successfully distinguished using pollen quantitative and qualitative traits, confirming the importance of pollen morphology to diagnose characters to correctly identify honeybee flora.

Palyno-anatomical microscopic characterization of selected species of Boraginaceae and Fabaceae

Palyno-anatomical characterization of some selected species of Boraginaceae and Fabaceae using light microscopy (LM) and scanning electron microscopy (SEM) was conducted. Six species of them belongs to four genera of family Boraginaceae and other six species belongs to four genera of Fabaceae. The current study aimed to investigate palyno-anatomical features for correct identification and taxonomic significance. Pollen grains were acetolyzed and observed both qualitatively and quantitatively through light microscopy and scanning electron microscopy. Statistical data was analyzed through cluster analysis which categorized plants into clusters. Principal component analysis (PCA) was carried out to illustrate morphological variation among selected plant species. Studied plant species showed variation in shape, size, aperture type, exine ornamentation of pollen, size and shape of epidermal cells, types of stomata, guard cells, subsidiary cells and trichome types. Exine thickness was recorded maximum 2.30 ± 0.1 μm in Lablab purpureus and minimum 1.05 ± 0.2 in Gastrocotyle hispida. PCA summarized 73.78% of accumulative variance. Trichome index was observed highest 62% on the adaxial surface of Heliotropium europaeum and lowest 21% on adaxial surface of L. purpureus. These findings reinforce the importance of palyno-anatomical features in the characterization and identification of taxa. It was concluded that description of palyno-anatomical characteristics presented in this study, highly contribute to our knowledge for correct identification of plant species.

Use of scanning electron microscopy to analyze sculpturing pattern and internal features of pollen grain wall in some members of Astragaleae (subfamily: Papilionoidae)

Palynological features of tribe Astagaleae L. have been observed with scanning electron microscopy (SEM), to assess features that can be used to re-examine the placement and taxonomic position of tribe. The palynomorph attributes of 10 species included in three genera of Astragaleae (Astragalus L., Glycyrrhiza L., and Oxytropis DC.) are investigated. The assignment of genus Oxytropis in tribe Astragaleae was also reevaluated based on pollen characters. Pollen appear to be prolate, prolate-spheroidal, and subprolate. Polar axis size (P) varies from 31.3 μm ±1 to 17.5 μm ±1.4 and equatorial axis size (E) varies from 22.2 μm ±1.8 to 13.1 μm ±0.9. Prominent apertures found consistently dispersed along the surface of pollen. Three kinds of ornamentation pattern were recorded, that is, reticulate or reticulate-perforate and perforate. The studied species display variation in equatorial and polar diameter, aperturation and sculpturing pattern, exine thickness, and pollen shape. On the basis of descriptive pollen features, a dichotomous taxonomic key and UPGMA analysis has been made for effortless and quick identification. The study concluded that disparities of the entire features are typically unrelenting and concerned with the species and shows potential systematic significance. The combination of palynological attributes in association with additional traits has prospective for systematic identification at species and genus level.

Microscopic techniques for fabrication of polyethersulfone thin-film nanocomposite membranes intercalated with UiO-66-SO3 H for heavy metal ions removal from water

Environmental remediation of heavy metals from wastewater is becoming popular area in the field of membrane technology. Heavy metals are toxic in nature and have ability to bioaccumulate in water bodies. In current study, zirconium-based metal organic frameworks (MOFs), that is, UiO-66 and UiO-66-SO₃ H with a mean diameter of 200 nm were synthesized and intercalated into polyethersulfone (PES) substrate to fabricate thin-film nanocomposite (TFN) membranes via an interfacial polymerization (IP) method. TFN membranes exhibit higher selectivity and permeability as compared to thin-film composite (TFC) membranes for heavy metals, such as cadmium (Cd) and mercury (Hg). Zirconium-based MOFs are highly stable in water and due to smaller pore size enhanced hydrophilicity of TFN membranes. In addition, TFN membrane with functionalized MOF (UiO-66-SO₃ H) performed best as compared to TFC and TFN with UiO-66 MOF. The effect of loading of different weight percentages (wt%) of both MOFs for TFN membranes was also investigated. The TFN membranes with loading (0.2 wt%) of UiO-66-SO₃ H displayed highest permeability of 9.57 LMH/bar and notable rejections of 90% and 87.7% toward Cd and Hg, respectively. To our best understanding, it is the first study of intercalating functionalized UiO-66-SO₃ H in TFC membranes by IP and their application on heavy metals especially Cd and Hg.

Seed morphology and sculpture of invasive Impatiens capensis Meerb. from different habitats

Impatiens capensis is an annual plant native to eastern North America that is currently spreading across Europe. In Poland, due to this plant's rapid spread in the secondary range and high competitiveness in relation to native species, it is considered a locally invasive species. The microstructure of seeds is an important tool for solving various taxonomic problems and also provides data useful for determining the impact of various environmental factors on the phenotypic variability of species. This issue is particularly important in regard to invasive species which occupy a wide range of habitats in the invaded range. There are few reports on seed size and thus far no descriptions of the seed ultrastructure of I. capensis in the analyzed literature. We present new data on the seed morphology of I. capensis growing in different habitats and conditions in the secondary range of the species. The studied populations differed significantly in each of the investigated traits (seed length, width, circumference, area, roundness, and mass). Our findings showed that anthropogenic disturbances in habitats and some soil parameters (presence of carbonates, potassium, loose sand, and moisture) were statistically significant with various seed sizes and morphology in the studied populations of I. capensis. Moreover, our studies showed maximum seed length (5.74 mm) and width (3.21 mm) exceeding those values given in the available literature. For the first time, we also provide a detailed SEM study of the ultrastructure of the seed coat of I. capensis. There are two types of epidermal cells on the seeds: (a) between the ribs (elongated with straight anticlinal walls, slightly concave outer periclinal walls, and micropapillate secondary sculpture on the edges with anticyclic walls), and (b) on the ribs (isodiametric cells with straight anticlinal walls and concave outer periclinal walls). Unlike the variability of size and weight of seeds, the coat ornamentation has turned out to be a steady feature within the studied secondary range of I. capensis.

Achene micromorphology and its taxonomic significance in some species in Taraxacum sect. Palustria (Asteraceae)

The genus Taraxacum is one of the largest and taxonomically most complicated apomictic genera. Currently, it is considered to consist of over 2800 species placed within 60 sections. Due to the large number of species, and their uniform morphological design and plasticity of leaves, the identification of plants at the species level is challenging even for specialists. This problem significantly hinders the study of their properties and the rational use of these valuable medicinal and nutritional plants. This paper presents the results of research on the morphology and micromorphology of achenes of 28 Taraxacum species of sect. Palustria and for comparison one species per section of: Erythrosperma, Naevosa, Piesis, and Taraxacum. The achenes were measured with a stereoscopic microscope and a biometric program, and micromorphological studies were performed by scanning electron microscopy. It has been shown that traits associated with achene morphology and micromorphology have a high diagnostic value, allowing us to distinguish sections as well as species within the sect. Palustria. Based on the examined achene features, a dichotomous key for determining the studied species was constructed.

Pollen morphology and viability of Tillandsia (Bromeliaceae) species by light microscopy and scanning electron microscopy

Tillandsia is the bromeliad genus containing the largest number of species, with wide geographic dispersion and an important ecological role in the ecosystems. Investigations of pollen morphology are important to support taxonomic and conservation studies as well as to choose promising species for cross-pollination to obtain hybrids. The objective of this study was to evaluate the morphology, production, and viability of pollen grains of 24 Tillandsia species that naturally occur in the state of Bahia, Brazil. Pollen grains were acetolized and analyzed by scanning electron microscopy. The pollen were germinated in vitro in two culture media (BM and BKM) and collected at three floral development stages (pre-anthesis, anthesis and post-anthesis). Pollen viability also was analyzed by staining with Alexander's solution and acetocarmine in three floral development stages. Variations in the ornamentation and size of the pollen were observed among the species studied, with the majority having medium size, while T. polystachia and T. juncea had large grains and the subgenera Diaphoranthema and Phytarrhiza had small grains. The pollen of the majority of species had bilateral symmetry, with a single irregularly shaped colpus, semitectate exine and reticulated-heterobrochate surface. The pollen presented high germination percentage, tube length and viability according to the histochemistry, except for T. recurvata, T. usneoides and T. loliacea. The BKM medium and collection of pollen during anthesis produced the best results for the Tillandsia species. The results can support studies of the taxonomy and conservation of these species, which have great environmental importance and high value for ornamental purposes.

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.