Pollen Micromorphology Research Articles

Pollen micromorphology and ultrastructure between two isolated species of Colchicum L. in Iran

Pollen micromorphology and ultrastructure of Colchicum kotschyi and Colchicum robustum with palynological isolated position in a previous research were examined by Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The observations showed that all quantitative characters of pollen micromorphology varied in the studied taxa. Although, pollen grains in both species were oblate. Two pollen types, two major exine ornamentations in the equatorial surface of pollen grain with two kinds of pore intine ornamentation were seen during this research. Regarding sporoderm data, the thickness of the pollen wall layer, state of the endexine layer, and number of intine layers of C. kotschyi were different from C. robustum. Sporoderm characters strongly supported the unique position of C. robustum resulting from previous palynological research.

Characterization of the floral traits, pollen micromorphology and DNA barcoding of the edible flowers from three basil taxa (Lamiaceae)

AbstractThe edible flowers sector is expanding due to the popularity and uses in culinary recipes of different species. In particular, flowers of Ocimum basilicum L. and related taxa are increasingly used for their aromas and nutritional value. However, there is limited information regarding their morphological characteristics and molecular profiles, which are both important to perform a quality control of food, and to avoid contaminations. Hence, our aim was the study of three basil taxa (O. basilicum ‘Cinnamon’, O. basilicum ‘Blue Spice’, and the hybrid O. × africanum Lour.) to obtain data useful for taxa identification and to understand which traits could be linked to their chemodiversity. The plants were grown in a greenhouse starting from seeds. Flowers were collected at anthesis; the morphology of calyxes, corolla and pollen grains was characterized; DNA barcoding analyses were performed. All taxa were identified only as O. basilicum by molecular analyses, but two haplotypes were distinguishable. All taxa were identifiable due to the presence/absence of specific glandular trichomes, and by pollen size and number of colpi. ‘Cinnamon’ and O. × africanum showed more morphological affinities to each other, but histochemical analyses suggested the separation of the three taxa. Pollen grains from ‘Cinnamon’ had the smallest diameter in polar view and were hexacolpate, while ‘Blue Spice’ pollen showed the highest diameter with grains being hexacolpate/octacolpate, similarly to O. × africanum. Our interdisciplinary study provides the first information for authenticating these basil cultivars in packaged products for human consumption.

THE PHARMACEUTICAL BOTANICAL STUDIES ON THE ENDEMIC Asperula pestalozzae Boiss. (RUBIACEAE)

In this study, endemic Asperula pestalozzae Boiss. (Rubiaceae) was investigated in aspects of pharmaceutical botany. The morphological, anatomical, micromorphological, palynological, and chemical (antioxidant activity and total amount of phenolic substance) characteristics were reported in detail for the first time. Expanded descriptions and images of A. pestalozzae were given. The anatomical description was presented in detail and supported by photographs. The stem is usually angular or orbicular shaped and the leaf is monofacial. Its trichome and pollen micromorphology were examined with a scanning electron microscope (SEM). The pollen grains of A. pestalozzae are monad, radial symmetry, isopolar, and hexacolpate (sometimes heptacolpate). DPPH and ABTS radicals were used to determine antioxidant activity. The DPPH 50% inhibition concentration (IC50) value was found to be 0.0011±0.0002 mg/ml for standard gallic acid and 0.134±0.017 mg/ml for A. pestalozzae extract. 0.1 mg/ml extract calculated 0.022±0.36 Mm TEAC activity; 1.437±0.51 mM TEAC activity was determined in 10 mg/ml extract. The total amount of phenolic substances was calculated as 53 mg gallic acid equivalent (GAE).

Pollen micromorphology of selected Caesalpinioideae taxa and its taxonomic role

Pollen micromorphology of selected Caesalpinioideae taxa and its taxonomic role

Pollen and Floral Organ Morphology of 18 Oil-Tea Genotypes and Its Systematic Significance

Oil-tea belongs to the Camellia genus, an important oil crop in China. However, oil-tea is taxonomically challenging due to its morphological variation, polyploidy, and interspecific hybridization. Therefore, the present study aimed to investigate the flower organs’ morphology and pollen micro-morphology of 18 oil-tea genotypes in detail and discussed their significance for oil-tea taxonomy. The quantitative parameters of flowers were measured using Vernier caliper measurements. Pollen morphology was observed and photographed using scanning electron microscopy (SEM). The results indicated that the flower size varied significantly among the tested oil-tea genotypes, with the corolla diameter ranging from 42.25 μm in C. meiocarpa ‘LP’ to 89.51 μm in C. oleifera ‘ASX09’. The pollen grains of oil-tea are monads and medium grade in pollen size. There were two types of polar views, including triangular or subcircular, with a polar axis length (P) ranging from 27.5 μm in C. oleifera ‘CY67’ to 59.04 μm in C. mairei (H. Lév.) Melch. var. lapidea (Y.C. Wu) Sealy. The equatorial views exhibited oblate, spherical, or oblong shapes, with an equatorial axis length (E) of 21.32 to 41.62 μm. The pollen exine sculpture was perforate, verrucate, and reticulate. The perforation lumina diameter (D) ranged from 0.29 μm in C. magniflora Chang to 1.22 μm in C. yuhsienensis Hu, and the perforation width (W) varied from 0.77 μm in C. osmantha to 1.40 μm in C. gauchowensis ‘HM349’, respectively. Qualitative clustering analysis (Q-type cluster) and principal component analysis (PCA) were conducted using eleven indexes of flower and pollen morphology, and the 18 oil-tea genotypes were classified into three categories. In addition, the correlation analysis showed that there was a significant correlation between pollen size and flower morphology or pollen exine sculpture. These results offer valuable information on the classification and identification of the 18 oil-tea germplasm resources.

Investigation of the Leaf and Pollen Micromorphology of Maples (Acer L.) of Iran

Investigation of the Leaf and Pollen Micromorphology of Maples (Acer L.) of Iran

Studies on pollen micro-morphology, pollen storage methods, and cross-compatibility among grape (Vitis spp.) genotypes.

The knowledge of pollen morphology, suitable storage condition, and species compatibility is vital for a successful grapevine improvement programme. Ten grape genotypes from three different species, viz., Vitis vinifera L., Vitis parviflora Roxb., and Vitis champini Planc., were studied for their pollen structure and pollen storage with the objective of determining their utilization in grape rootstock improvement programs. Pollen morphology was examined through the use of a scanning electron microscope (SEM). The viability of the pollen was assessed using 2,3,5-triphenyltetrazolium chloride (TTC). In vitro pollen germination was investigated using the semi-solid medium with 10 % sucrose, 100 mg/L boric acid, and 300 mg/L calcium nitrate. The results revealed variations in pollen micro-morphology in 10 genotypes, with distinct pollen dimensions, shapes, and exine ornamentation. However, species-wise, no clear difference was found for these parameters. Pollen of V. parviflora Roxb. and Dogridge was acolporated and did not germinate. The remaining eight genotypes exhibited tricolporated pollen and showed satisfactory in vitro pollen germination. Storage temperature and duration interactions showed that, at room temperature, pollen of most of the grape genotypes can be stored for up to 1 day only with an acceptable pollen germination rate (>30 %). However, storage for up to 7 days was successfully achieved at 4 °C, except for 'Pearl of Csaba'. The most effective storage conditions were found to be at -20 °C and -196 °C (in liquid N2), enabling pollen storage for a period of up to 30 days, and can be used for pollination to overcome the challenge of asynchronous flowering. Four interspecific combinations were studied for their compatibility, among which V. parviflora Roxb. × V. vinifera L. (Pusa Navrang) and V. parviflora Roxb. × V. champini Planc. (Salt Creek) showed high cross-compatibility, offering their potential use for grape rootstock breeding. However, V. parviflora Roxb. × V. vinifera L. (Male Hybrid) recorded the lowest compatibility index among studied crosses. In the case of self-pollinated flowers from V. parviflora Roxb. and V. parviflora Roxb. × V. champini Planc. (Dogridge), pollen failed to germinate on the stigma due to male sterility caused by acolporated pollen. As a result, the flowers of these genotypes functioned as females, which means they are ideal female parents for grape breeding without the need for the tedious process of emasculation.

Does palynotaxonomy contribute to the systematics of the genus? The section Multicaulia of the genus Hedysarum (Fabaceae) example in Türkiye

The purpose of the current work was to assess the systematic and taxonomic significance of the pollen morphological characteristics of the Multicaulia section of Hedysarum species found throughout Türkiye using scanning electron microscopy (SEM) and light microscopy (LM) techniques. For this reason, seven different species currently classified in the Multicaulia section were collected from various localities. The pollen grains were nonacetolyzed, prepared and directly measured according to the Wodehouse method. Pollen grains were found to be subprolate in H. nitidum but prolate in others and the exine sculpturing pattern was determined to be microreticulate-perforate in six taxa while only H. varium subsp. syriacum had reticulate-perforate sculpture. The minimum exine thickness was measured at 0.96 μm in H. varium subsp. varium, while among the investigated species, H. nitidum had an exine measurement of 1.38 μm. In this study, multivariate analysis was used to investigate nine qualitative and quantitative features. Data cluster analysis revealed that the pollen characteristics were important in helping to distinguish the different species from one another. The results demonstrated that the genus Hedysarum of the section Multicaulia was divided into two major groups based on variations in pollen dimensions. The usefulness of certain pollen morphological traits was assessed, and the congruency of the palynomorphological investigations was examined. The findings demonstrated the significance of pollen micromorphology in precisely identifying and categorizing the Multicaulia section.

Pollen micromorphology and ultrastructure of some species of Tulipa and its taxonomical implication

Pollen micromorphology of nine species of the genus Tulipa (including three subgenera Tulipa, Clusiana, and Eriostemones) and one species from the genus Amana were examined using light microscopy (LM) and scanning electron microscopy (SEM). Moreover, the pollen wall ultrastructure of five selected taxa from the studied species of Tulipa and one species of Amana were examined by transmission electron microscopy (TEM). Pollen micromorphology (especially exine ornamentation, sulcus margin and sulcus membrane ornamentation, operculum ornamentation) and pollen wall ultrastructure (sporoderm thickness, tectum/foot layer ratio, number of intine layers in sulcus membrane region) varied in the studied taxa. A dendrogram of the pollen micromorphological characteristics (obtained from LM and SEM observations) distinguished three pollen types and six subtypes. Amana edulis (subtype A) and Tulipa biebersteiniana (subtype B) were placed in pollen type 1. Tulipa tetraphylla (subgenus Eriostemones) with Tulipa urumiensis and Tulipa kolpakowskiana (subgenus Tulipa) were placed in pollen type 2. Tulipa clusiana (subgenus Clusiana) and Tulipa suaveolens (subgenus Tulipa) belonged to pollen type 3. Information from pollen wall ultrastructure provided better differentiation of these taxa for better taxonomical resolution. Pollen micromorphology along with ultrastructure can be useful for better understanding the systematic affinities of the species in the genus Tulipa and its relation with the genus Amana and for establishing subgenus rank for T. biebersteiniana and T. clusiana.

Revealing the intricate microcosm: Advancing invasive species pollen analysis through scanning microscopy of ultra sculpture.

Micromorphological visualization of plant surface peculiarities provides valuable characters for the precise identification of plant species. Invasive alien species, introduced outside their native range, pose significant ecological, and health challenges. This study focuses on micromorphological investigations of selected invasive plant species belonging to the families Amaranthaceae, Asteraceae, Moraceae, Crassulaceae, Cannabaceae, Fabaceae, Commelinaceae, and Oxalidaceae. The study employs scanning electron microscopy (SEM) to analyze the species micromorphology of pollen structure in depth to characterize the sculpturing patterns. Additionally, the study examines the pollen characteristics of these invasive plants, including shape, size, and fertility, along with exine sculpturing. The maximum polar diameter was observed for Senna tora (41.2 μm). The spines in Achillea fragrantissima were measured to have dimensions of approximately 1.91 μm in length and 2.11 μm in width. The findings shed light on the allergy-causing potential of these invasive species, providing crucial information for accurate identification and effective management strategies to safeguard the indigenous flora of the region. The study contributes to the knowledge base for botanists, taxonomists, policy makers, climate experts, and biodiversity specialists. RESEARCH HIGHLIGHTS: Integrating SEM to analyze the pollen of invasive species. Unveiling pollen micromorphology of invasive species. Exploring the microscopic realm of invasive pollen to accurately identify the species.

Studies of the pollen characteristics and the taxonomic significance of Impatiens from the Yunnan–Guizhou Plateau

ABSTRACT Impatiens is rich in germplasm resources, with more than 260 species in China. A study on the pollen micromorphology of Impatiens by scanning electron microscopy (SEM) showed that the pollen characteristics were richly diverse, and there was some correlation among the characteristics. In addition, the micromorphological index can be used for an effective cluster analysis of Impatiens. However, there was high interspecific similarity in some Impatiens, and the classification of Impatiens cannot be accurate to the species using pollen characteristics. Based on the classification conditions of Impatiens, the characteristics of the pollen structure were found to be useful to classify Impatiens into subgenera or smaller groups. The macroscopic characteristics and the number of sepals (NS) were used as references, which enabled the conclusion that there were 11 indices in the pollen micromorphological index, and the taxonomic effect was greater than the NS. In summary, the pollen micromorphology of Impatiens plays an important role in the classification of Impatiens. The purpose of this study was to explore this characteristic of Impatiens, which has some reference significance to supplement the pollen characteristics and palynological classification of Impatiens. The goal for this research was to aid in the interspecific identification and genetic breeding of Impatiens.

Micrometer insights into Nepeta genus: Pollen micromorphology unveiled

This study provides a comprehensive pollen micromorphology within the Nepeta genus, revealing intricate details about the pollen grains' structure and characteristics. The findings shed light on the evolutionary and taxonomical aspects of this plant genus, offering valuable insights for botanists and researchers studying Nepeta species. The pollen grains of 18 Nepeta species were studied using scanning electron microscopy (SEM) and light microscopy (LM) in Northern Pakistan. At the microscale, pollen quantitative measurements, qualitative traits, and diverse sculpturing patterns were reported and compared. Significant differences in pollen size, shape, ornamentation, and sculpturing patterns were discovered among the Nepeta species. Our data show that exine sculpturing is quite diverse, with most species exhibiting a reticulate perforate pollen pattern. Nepeta connata, Nepeta discolor, Nepeta elliptica, revealed a distinct bireticulate perforate exine stratification. Hexazonocolpate pollen is the most common. Furthermore, the surface membrane attributes of the colpus varied greatly, ranging from rough, scabrate, psilate, to sinuate patterns. Principal Component Analysis (PCA) was used to discover the key factors influencing pollen diversity. PCA results showed that polar and equatorial diameters, colpi size, and exine thickness were the most influential pollen features between Nepeta species. This study adds to our understanding of pollen morphology in the Nepeta genus, offering information on the vast range of characteristics found in this economically important group. The extensive characterization of pollen features provides useful insights for the categorization and differentiation of Nepeta species, adding to the Lamiaceae micromorphology.

A Detailed Study of Leaf and Pollen Micromorphology of Some Species of Parietaria and Its Systematic Implication (Urticaceae)

Parietaria L. is a genus comprised of 20 species distributed throughout temperate and subtropical areas of the world. The leaf and pollen characters of four species of Parietaria from different locations in Iran were investigated with light and scanning electron microscopy, in order to assess their diagnostic significance to provide additional evidence on species delimitation. All pollen grains were small in size and found to be porate. Most of the pollen characters, such as shape and sculpturing of pollen grains, exine diameter, were overlapped between species and indicated limited taxonomic value. The pore and annulus diameter could be provided additional taxonomic characters that can be used for species delimitation in the genus. Moreover, the leaf epidermis provided new qualitative data (laminar hydathodes, bladder-based trichomes) that could delimit the species. The characters like twin stomata and laminar hydathode observed in P. officinalis were reported for the first time in this genus.

Pollen Micromorphology of Mangrove Species in South Sumatra Coastal Area, Indonesia

Pollen Micromorphology of Mangrove Species in South Sumatra Coastal Area, Indonesia

Taxonomic notes of the genus Gagea sensu lato including Lloydia based on palynological features

Pollen micromorphology and sporoderm ultrastructure of 10 species of the genus Gagea sensu lato (including Lloydia) were examined by light microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed variation in all quantitative characters of pollen micromorphology. In terms of qualitative characters, oblate pollen shape and two pollen types (medium and large) were seen. Exine ornamentation of the equatorial surface differed from that of the sulcus margin region. Intine ornamentation in the sulcus region was similar in all taxa. Furthermore, the situation of the furrow among cristates and granulates in muri differed, as did the lumina connections. The qualitative and quantitative characters of the pollen sporoderm, such as the presence or absence of endexine, number of intine layers in the sulcus region, and sporoderm thickness, also varied. A dendrogram of all qualitative and quantitative palynological characters, created by the unweighted pair group method with arithmetic mean (UPGMA) based on Euclidean distances, identified six pollen types. Palynological types strongly supported the transfer of Lloydia to Gagea. However, the palynological dendrogram did not support reducing the number of sections in these taxa. A dichotomous key is also presented based on pollen micromorphology and ultrastructure.

Pollen morphology in Iranian species of Onosma (Boraginaceae)

The genus Onosma is one of the largest genera of the family Boraginaceae, with about 240 species distributed mainly in the mountainous habitats of the Irano-Turanian region. Determining the boundaries of the species in this genus has been faced with several problems, and their relationships are still poorly understood based on the recent phylogenetic studies. Therefore, the present study was designed to investigate the pollen micromorphology of 40 species of Iranian Onosma by scanning electron microscopy (SEM), to identify attributes perhaps important for a subgeneric classification. On the basis of pollen SEM images, three types of pollen shapes were observed, and the prolate pollen shape was predominant. In addition, three aperture types were observed. All species studied had microechinate, perforate, microechinate, verrucae, microechinate, perforate, and verrucate, microechinate exine sculpture. Based on cluster analysis and principal component analysis, the species studied were divided into two main groups showing different quantitative and qualitative traits. Therefore, the results of this study suggest that micro-morphological pollen traits can be used as valuable evidence in the taxonomy of the genus Onosma. However, we believe that palynology alone cannot successfully identify species in this genus and should use comprehensive evidence to identify species.

Pollen Micromorphology among Amaranthaceous Species from Desert Rangeland: Exine Stratification and their Taxonomic Significance

The aim of the study was to visualize the micromorphology of Amaranthaceous pollen using scanning electron microscopy collected from the Thal Desert. Field collection was conducted from July to September 2021. A total of 14 taxa of the family Amaranthaceae were collected which belong to nine genera. Achyranthes aspera, Aerva javanica, Aerva lanata, Amaranthus graecizans, Amaranthus retroflexus, Amaranthus viridis, Bassia indica, Chenopodium album, Chenopodium ficifolium, Chenopodium murale, Digera muricata, Haloxylon stocksii, Salsola tragus, and Suaeda fruticosa were studied in terms of pollen morphotypes. Pollen were acetolyzed and observed under optical and scanning microscopy. Qualitative and quantitative characters were measured to analyze the pollen to uncover its taxonomic significance. Qualitative characters observed were the shape of pollen in polar and equatorial views; the most frequent shape observed was spheroidal in the polar view, whereas in the equatorial view, prolate spheroidal was the dominant shape. Exine ornamentation is the key characteristic of pollen which is very helpful, and eight different types of ornamentations were observed in collected taxa: smooth sparsely granulate, scabrate‐spinulose, microspinulose perforate, microechinate scabrate to metareticulate, granulate, nanospinulate, granulate‐spinulose perforate, granulate‐perforate echinate, and microechinate perforate. Periporate‐type aperture was observed among all taxa. Mesoporia, ektexinous bodies, and tectum features also show variations among Amaranthaceous grains. In quantitative character, A. retroflexus recorded highest in polar view 26.3 μm and the lowest was of C. album 12.2 μm. Highest P/E index ratio was recorded in S. fruticosa (1.12) whereas the lowest for D. muricta (0.94). Exine thickness was highest in S. tragus 2.15 μm and lowest in A. graecizans 0.78 μm. The maximum number of pores was recorded as 32‐36 in D. muricata. Artificial taxonomic keys were constructed based on findings that reinforce the importance of the micromorphological ultrastructural diversity of pollen among Amaranthaceous taxa. It was concluded that the descriptions of pollen morphotypes presented greatly contribute to our understanding of desert species identification.

Taxonomical relations of tribe Lilieae (Liliaceae) based on palynological issues

Pollen micromorphology and ultrastructure of fifteen species from the genera Cardiocrinum, Fritillaria, Lilium, and Notholirion were examined by Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). Our results showed that all quantitative characters of pollen micromorphology (LM and SEM observation) varied in the studied taxa. Pollen grains in all studied species were oblate except Notholirion bulbuliferum with oblate-spheroidal. The studied species of Fritillaria had medium pollen type and the rest showed large. Although, two major exine ornamentation in central region of equatorial surface and sulcus margin region were seen such as reticulate (taxa of Cardiocrinum) and reticulum-cristatum (taxa of genera of Lilium, and Notholirion). These characters were varied in taxa of Fritillaria in both regions (foveolate-rugulate, reticulate and foveolate). Also, there were three sulcus membrane ornamentation including striate-tuberculate (Fritillaria gibbosa), tuberculate (Lilium lophophorum and with the rest studied taxa of Fritillaria), and macrotuberculate (the genera Cardiocrinum, Lilium, and Notholirion). Moreover, three kinds of lumina types and two kinds of muri types were detected among these taxa. The qualitative and quantitative characters of the pollen wall were varied such as kind of endexine situation, number of intine layers in the sulcus membrane region, and thickness of elements from the pollen wall. Dendrogram of all qualitative and quantitative palynological characters constructed two pollen groups, five pollen types, and four pollen subtypes. The palynological dendrogram verified that Nomocharis is part of genus Lilium. Palynological types supported the heterogeneous phylogenetic situation of Cardiocrinum. Palynological subtypes were partly valuable in delimitation of sectional levels of the genus Lilium.

Solenopsis bacchettae (Campanulaceae, Lobelioideae), a new species from Sardinia

A new species of Solenopsis (Campanulaceae), S. bacchettae from Sardinia (Italy) is described and illustrated. Previously, it was misidentified as S. bivonae, due to its habit and corolla shape, but several relevant morphological features allow to distinguish it from the latter. Its morphology, seed coat and pollen micromorphology, ecology, distribution, conservation status and taxonomic relationships are presented.

Exploration of pollen traits and their taxonomic relevance in selected taxa of the subfamily Papilionoideae from Hainan Island, China

The Papilionoideae is one taxonomically complex subfamily with high economic and medicinal potential. The pollen micro-morphology and taxonomic relevance of this subfamily are still poorly known in the island. Therefore, this study aims to provide new palynological information to correctly identify and define species boundaries within the subfamily. The species were collected from different geographical regions of Hainan Island. Both light and scanning electron microscopic techniques were used to observe pollen traits. Additionally, principal component analysis was performed to elucidate the variation among the taxa. A significant variation was found in exine sculpturing i.e. most of the taxa have reticulate type pollen while Desmodium triflorum has a psilate exine pattern. Variations were found on the surface of the reticula that can help to delimit the species from one another. Pollen type was observed as tricolporate and rarely tricolpate. Similarly, the colpus surface membrane morphology may also vary significantly from species to species i.e. scabrate, verrucate, gemmate, rugulate patterns. Besides, the mergo having various sculpturing found in Canavalia rosea, Desmodium triflorum, D. microphyllum Glycine max, Macroptilium atropurpureum, Erythrina crista-galli and Zornia gibbosa should be considered as a potential taxonomic trait for the subfamily. The maximum P/E ratio was found in Zornia gibbosa (2.24). Similarly, the maximum pollen size was found in Alysicarpus vaginalis (34.64 × 33.99 µm). Our study explored the pollen morphological traits and can be helpful to correctly identify the species and define species boundaries within Papilionoideae at various taxonomic levels. This study strengthens and supports the taxonomic position of the subfamily and will provide bases for further phylogenetic and molecular studies of Papilionoideae.