Pollen Morphology Research Articles

Pollen Morphology of Some Melliferous Rosaceae Species of the Leningrad Region

Abstract—Using light and scanning electron microscopes, the pollen morphology of 11 wild and introduced melliferous species widely distributed in the Leningrad Region and belonging to 9 genera of the Rosaceae family was studied. It was found that pollen grains of all the studied species are of medium size, 25–40 microns, occasionally slightly smaller, most of them are 3-furrowed, in Sanguisorba officinalis L. 6-furrowed, with a striate or derived from it sculpture. In the dispersed state, pollen is easily determined to the family, and often to the genus. However, species of Rosa and Rubus are poorly distinguished by pollen. The data obtained can help honey producers to simplify the botanical identification of Rosaceae pollen in tested honey samples.

Palynological investigation of some Euphorbia L. (Euphorbiaceae) taxa from Turkey using light and scanning electron microscopy.

Euphorbia L., one of the largest genera of angiosperms, is represented by the subgenera Esula Pers. and Chamaesyce Raf. in Turkey. Subg. Esula is confined mainly to Eurasia, especially in the Mediterranean region, and has not yet been studied in detail palynologically. In the present study, the pollen morphology of 14 taxa belonging to the sections Helioscopia Dumort., Myrsiniteae (Boiss.) Lojac., Pithyusa (Raf.) Lázaro, Patellares (Prokh.) Frajman, Exiguae (Geltman) Riina & Molero, Paralias Dumort., and Esula (Pers) Dumort. of Euphorbia L. subg. Esula Pers. from European Turkey was examined using light and scanning electron microscopy. The pollen grains were found to be trizonocolporate, isopolar, radially symmetrical, medium in size, and oblate spheroidal and suboblate in shape. Ectoapertures were elongated colpi with distinct margins, widened at the equatorial region, and tapered at the ends; margo was present in all samples as a smooth exine surrounding the colpi. The endoapertures were lolongate pori with distinct costae. The exine was tectate-perforate. The ornamentation was perforate, microreticulate-perforate, microreticulate-perforate with rugulose, or microreticulate-perforate with a heterobrochate pattern. The sexine was generally thicker than the nexine, with some exceptions where the sexine was almost equal to the nexine. Pollen size, pollen shape, and exine ornamentation have taxonomic importance in distinguishing species; however, these features do not provide strong support for grouping or delimitating the taxa at the sectional level. RESEARCH HIGHLIGHTS: Pollen size, pollen shape, and exine ornamentation are taxonomically important for distinguishing Euphorbia species. The exine ornamentation was observed to be perforate, microreticulate-perforate, microreticulate-perforate with a rugulose pattern, and microreticulate-perforate with a heterobrochate pattern.

Pollen morphology of Ipomoea L. from Garhwal Himalaya, India

Pollen morphology serves as a valuable tool for identification, phylogenetic analysis and evolutionary studies. The present study aims to investigate the pollen morphology of 12 species of the genus Ipomoea L. (a diverse and economically important genus within the family Convolvulaceae) from Garhwal Himalaya, India. Fresh flower buds were collected from the study area and pollen preparation completed using the acetolysis method. The morphology of the pollen grains were examined using light microscopy and scanning electron microscopy. Pollen grains of all the studied species were apolar, spheroidal, pantoporate, subtectate with fine reticulation and echinate, but they differed from one another in their size, number of spines and pores, spine length and spine types. The size of grains ranged from 53.3 to 128.7 μm. Cluster analysis was performed based on pollen characters to show the relationship among the species; a key was prepared and is discussed. The observed variation in pollen morphological traits gives important taxonomic information that is useful for distinguishing Ipomoea species and establishing taxonomic and phylogenetic relationships.

Contribution to the pollen morphology of Astragalus L. section Aegacantha Bunge (Galegeae-Fabaceae) and its systematic significance

Astragalus L. sect. Aegacantha Bunge includes 57 described species, mostly confined to Southwest Asia and Central Asia. We studied the pollen morphology of 17 species of this section present in Pakistan. Pollen morphology of sect. Aegacantha species is poorly investigated despite its systematic importance. The main aim of this study is to determine and document the pollen characters that can assist in the taxonomic identification of species in this difficult section. Pollen slides were prepared following acetolysis and examined by both light and scanning electron microscopy. Pollen size varies, with the polar axis ranging from 32.91 to 43.10 μm and the equatorial axis from 22.91 to 28.47 μm. Pollen is sub-prolate (1.15–1.33) to prolate (1.34–2.00) in shape, small to medium in size, radially symmetrical, isopolar, trizonocolporate to tricolporate, and monad. Sculpture variations (i.e. reticulate, microreticulate, perforate, microperforate, regulate, microregulate and granulate) were observed around the apertural, meridional and polar regions. Ordination analysis (principal component analysis (PCA)) revealed that the quantitative characters of pollen morphology are the most reliable characters for delimitation of species within section Aegacantha. Cluster analysis (unweighted pair group method using arithmetic average (UPGMA)) shows a partial relationship between the Aegacantha taxa clustered based on pollen characters and supports the general morphology. Further, this study shows that the pollen traits provide a baseline for phylogenetic optimisation in the investigated Aegacantha section.

Pollen morphology of some Tanacetum L. (Asteraceae) taxa and its systematic value

Pollen morphology of some Tanacetum L. (Asteraceae) taxa and its systematic value

Pollen Morphology in Sorbus L. (Rosaceae) and Its Taxonomic Implications.

The genus Sorbus L. in the Rosaceae family is taxonomically challenging due to its morphological variation, polyploidy, and interspecific hybridization. In this study, we used scanning electron microscopy (SEM) to observe the pollen morphology of eighty species, representing six subgenera, in order to assess the differences within the genus Sorbus and its pollen characteristics. We conducted a cluster analysis on three qualitative and four quantitative characteristics. The results demonstrated that the pollen grains of the studied Sorbus species are isopolar and tricolporate. We identified five types of pollen shapes: suboblate, spheroidal, subprolate, prolate, and perprolate. The pollen ornamentation of the investigated species could be classified into five types: striate-perforate, striate, cerebroid-perforate, cerebroid, and foveolate. Interestingly, within the same subgenera, different species exhibited multiple types of characters. The cluster analysis indicated that all 80 species could be divided into six groups, with group B consisting exclusively of species from the subgenus Sorbus. Although pollen micro-morphologies alone do not provide sufficient evidence to establish the taxonomic relationships of the subgenera within Sorbus, they do offer valuable information for species-level taxonomic treatment.

Relationship between pollination syndromes, pollen morphology and plant ecology in Quaternary deposits of the Cerrado

This study presents morphological descriptions and ecological information for 58 terrestrial pollen taxa and seven water-related pollen taxa from the Brazilian Cerrado, obtained from two sediment cores, Lake Feia (LFB1) and Getulio Swamp (VGE-17), encompassing the last 5000 and 15,000 cal yr BP, respectively. The relationships between the ecological and morphological traits (pollination syndrome, vegetation stratum and grain size) within each of the two depositional environments were investigated. In the LFB1 core, the pollen assemblages were dominated by arboreal pollen from closed physiognomies and lower storey trees (<10 m in height), while a combination of closed and open physiognomies was observed in the pollen assemblages from the VGE-17 core. The vast majority of the pollen taxa exhibited the entomophilous pollination syndrome, and a higher influx of entomophilous pollen was observed in both cores. Anemophilous and anemophilous/entomophilous syndromes were less well represented. Small and medium pollen grain classes were the most abundant, while the large pollen grain class was rare. The influx of small pollen grains was slightly more abundant in the lake record, while in the swamp record medium pollen grains were more abundant. Our results show that swamps and lakes differ in their representation of local versus regional pollen and in their sensitivity and responses to water-level changes. Landscape physiognomy also influences pollen dispersion: a closed physiognomy increases the local pollen signal, while a more open physiognomy results in better representation of local and regional signals.

Pollen morphology of columnar cacti from Tehuacán-Cuicatlán Valley, Mexico

The most important centre of diversity and endemism of columnar cacti in Mexico is the Tehuacán-Cuicatlán Valley (Puebla-Oaxaca states). The aims of this paper are (1) to provide a detailed description of the recent pollen morphology of 19 registered species that are found in this valley and (2) to develop a synoptic table to differentiate groups of species. This synoptic table is based on morphological features of pollen grains and the density of structural and sculptural elements observed using light and scanning electron microscopy. All analysed pollen grains were stenopalynous: isopolar monads, large, tricolpate with perforate tectate exine (sexine-nexine ratio 1:1), columellate structure with pattern of columellae distribution and spinulose sculpture. The spinules were always wider than they were tall. Although the 19 species of columnar cacti analysed in this study show highly similar types of pollen grains, we were able to characterise each of them with combined microscopy techniques.

Evaluation of reproduction biology of Prunus cerasoides

Prunus cerasoides have a high value in phytochemistry and pharmacology. It was classified as the Least Concern globally based on the IUCN red list due to its widespread distribution in eastern Asia. This research aims to evaluate the reproductive biology of P. cerasoides through the study of pollen morphology, pollen viability, stigma receptivity, and pollination in the Cibodas Botanical Garden, located in the Cibodas subdistrict of West Java, Indonesia. The pollen morphology was observed using SEM. Moreover, the pollen viability test was followed by the staining method (aceto-orcein 2%, I2KI 1%, TTC 1%) and in vitro pollen germination with thirteen treatments (aquadest [control]; 5-30% sucrose; and 5-30% sucrose + 5 ppm boric acid). Stigma receptivity was observed daily, from 7 days before anthesis until the anthesis stage. Furthermore, several types of pollination were evaluated, including open pollination, autogamy, geitonogamy, and allogamy. The results showed that the best staining method on P. cerasoides was aceto-orcein 2%, with pollen viability at 87.87%. The sucrose concentration of 25% at 72 hours of observation gave the highest pollen viability results, 52.48%. Stigma receptivity was optimal in the two days before anthesis until anthesis. The highest pollination efficiency was cross-pollination at 53.33%, with an average percentage of the total fruit set of 24.17%.

PLANT SEGREGATION AND POLLEN CHARACTERISTICS OF HIGHLAND PAPAYA (VASCONCELLEA PUBESCENS A.DC.) BASED ON SEX TYPES

Highland papaya (Vasconcellea pubescens A.DC.) is a member of the family Caricaceae and native to Ecuador. The plant’s introduction and cultivation were successful in specific highland areas of Indonesia but with limited growing areas. V. pubescens has monoecious and dioecious characteristics and allows fruit production from female dioecious and monoecious plants. This plant is valuable, and the knowledge about its sex pattern, though still limited, is crucial for its efficiency, productivity, and development. Hence, the presented study aimed to explain the patterns of plant segregation, as well as, pollen morphology and germination based on sex in V. pubescens. The investigations began by recognizing the total population of V. pubescens in its cultivated area for grouping and mapping according to sex. Observations on the pollen characteristics, such as, morphology and germination, used light microscopy and a Scanning Electron Microscope (SEM). The results revealed that the basis for plant segregation pattern depended on sex in male and female dioecious and monoecious plants of V. pubescens (1:5:1). In both sexes, the pollen morphological characteristics showed that the unit of monads, prolate spheroidal, radial, tricolporate, isopolar, reticulate, and P/E index of male dioecious pollen was 0.70, while monoecious was 0.52. Anthers and pollen grains from the male plant were round, but those of monoecious elongate more. However, no significant differences occurred among the sexes for pollens. The pollen grains from male flowers on male dioecious plants showed faster germination than monoecious individual plants, having a difference of 25.14 days.

Comparative Pollen Morphology of the Genus Chaenomeles Lindl. (Rosaceae): Diagnostic Features and Implications for Taxonomy

The taxonomic placements of Chaenomeles Lindl. (Rosaceae) and their intrageneric species have long been controversial. This research aims to explore the palynomorphological characters of all Chaenomeles extant species in detail and to compare the results with phylogenetic relationships and the taxonomic classification scheme. The pollen morphology of 30 individuals of six taxa of Chaenomeles was investigated using both light microscopy and scanning electron microscopy. The pollens were measured, observed and statistically analyzed for 12 quantitative features and 2 qualitative ones. The study revealed that the Chaenomeles pollens are monad, tri-colporate, medium in size (P = 32.78–42.74 μm, E = 30.42–36.31 μm) and prolatespheroidal to subprolate in shape (P/E = 0.98–1.35). Based on exine ornamentation observed under SEM, two sexine sculpture types (type I—striate with microperforations, type II—striate with macroperforations) and two subtypes (twisted-striate, reticulate-striate) were recognized in the genus. Statistical analysis identified some pollen characteristics with diagnostic importance, including pollen shape, colpus dimension, length or direction of striae and diameter of perforation. These characteristics may have diagnostic and taxonomic value for the genus Chaenomeles and the family Rosaceae. An artificial key to studied species, based on pollen micromorphological attributes, is also provided. The obtained result was basically consistent with that of molecular studies published earlier. This study, for the first time, provides palynological evidence for the hybrid origin hypothesis of C. sinensis and supports the placement of this species in the monotypic genus Pseudocydonia.

Unveiling the intricacies of Amaranthaceous pollen diversity: Advancing ultra sculpture analysis through LM and SEM.

Microscopic techniques can be applied to solve taxonomic problems in the field of plant systematic and are extremely versatile in nature. This study was focused on the new approaches to visualizing the imaging, tool to cover the micro-structural techniques applied to the pollen study of Amaranthaceae floral biology. In this detailed study, we used light microscopy and scanning electron microscopy to examine the shape and changes in pollen of 16 types of Amaranthaceae plants from the salty arid zone of Riyadh Saudi Arabia. We observed subtle variations among the studied species through meticulous examination of morpho-palynological features such as symmetry, size, shape, pore ornamentation, and exine characteristics. The pollen grains were round and had rough or prickly outer coverings. They had different numbers of tiny pores; some were slightly sunken. These findings were utilized to develop a pollen taxonomy key, facilitating accurate identification and classification of Amaranthaceous species. Our results shed light on the taxonomic significance of pollen morphology for species differentiation within the Amaranthaceae family. Furthermore, this study provides valuable insights into the influence of geographical and ecological factors on pollen diversity and evolution. This study of pollen imaging visualization of Amaranthaceous species contributes to the opportunity for taxonomic evaluation and fill knowledge gaps in studies of Amaranthaceous flora identification using classical microscopic taxonomic tools for their accurate identification. RESEARCH HIGHLIGHTS: The pollen characters of selected Amaranthaceae species were visualized using scanning electron microscopy to observe sculptural wall pattern. The comprehensive Amaranthaceous pollen examination approach allowed us to accurately identify their micromorphology. This high-resolution imaging technique provided detailed insights into the surface structures and ornamentation of the pollen grains.

Pollen morphology characterization of Dryades Groppo, Kallunki & Pirani, a new genus of Rutaceae, and its phylogenetically related species

Rutaceae (Sapindales) is represented by approximately 2040 species and 150–170 genera. Conchocarpus is the genus with the highest number of species and is circumscribed by a combination of character states, making it a polymorphic group. A recent study proposed a new genus, Dryades, formed by species formerly positioned in Conchocarpus. This study aims to describe the pollen morphology of Dryades species, comparing it with the palynology of phylogenetically related species, to present data that can characterize the species of Dryades. We analyzed the pollen grains of Dryades species and eight species of the genera Andreadoxa, Angostura, Erythrochiton, Galipea, Rauia and Conchocarpus. The pollen grains were acetolyzed, measured, described qualitatively, and analyzed quantitatively. Illustrations using light microscopy (LM) and scanning electron microscopy (SEM) are presented. Multivariate analysis was performed. The pollen grains are monads, isopolar, medium to very large in size, with subcircular to subtriangular amb, and oblate-spheroidal to prolate shape. The apertures are 3- or 5-colporate, varying in size (very small to very large colpi). The endoapertures are usually lalongate, rarely circular. The pollen grains analyzed are microreticulate, reticulate, macroreticulate, reticulate-baculate, baculate or verrucate-baculate. Both qualitative and quantitative characteristics of pollen grains proved to be important in distinguishing genera and grouping species within genera (in particular, the number of apertures, the length of the ectoaperture, the exine ornamentation and the size of the pollen grains). Dryades species show similarities in pollen morphology to species of related genera such as Andreodoxa, Galipea and especially Rauia. The shape of pollen grains and the number of apertures in Dryades are distinct from those found in Conchocarpus macrophyllus. The pollen data observed in this study confirm the pollen diversity of Rutaceae.

Pollen morphological studies on selected species of Jatropha L. through light microscopy from Hyderabad, Telangana State.

Pollen morphology is one of the important tools for taxonomic studies and helps in the identification of medicinal plants. Pollen characterization of four species of Jatropha viz., Jatropha gossypifolia, Jatropha integerrima, Jatropha multifida, and Jatropha podagrica. collected from Greater Hyderabad of Telangana State, India during 2022-23 was carried out by using Light Microscope (LM). The pollen types looked similar but varied in size and shape. The pollen grains are spheroidal to circular, isopolar and radially symmetrical. Grains are inapertutate/omniaperturate with surface showing crotonoid pattern. The plants studied in the present work were known for their medicinal use having anti-inflammatory, antidiarrheal, antiophidian, analgesic, antipyretic, antimicrobial, healing, antianemic, antidiabetic, and antihemorrhagic activities and most important in traditional system of medicine.

Comparative Pollen Morphology of Selected Species of Blumea DC. and Cyathocline Cass. and Its Taxonomic Significance.

The pollen morphology of 20 species from Blumea and Cyathocline Cass. was investigated using a light microscope (LM) and scanning electron microscopy (SEM) to explore their taxonomic significance. This study showed that pollen grains of these species were usually tricolporate, rarely tetracolporate (B. sinuata). Nine pollen types were distinguishable through the exine sculpture characters and the number of apertures. It was easily distinguished Cyathocline from species of Blumea s. str. by its much smaller size (15.04 μm × 15.07 μm) and sparse and longer spines (24 spines, spine length 4.23 μm) with acute apex, which suggest that C. purpurea might not belong to the genus Blumea s. str. The palynological characteristics indicated that Section Macrophllae and Section Paniculatae of Blumea were not monophyletic groups. The pollen morphology differentiation of B. lacera clade is consistent with the interspecific relationship revealed by the molecular phylogenetic tree. However, the pollen morphology of the Blumea densiflora clade is inconsistent with the interspecific relationship based on molecular phylogenetic analysis. This palynology research can only partly support the previously published molecular phylogeny of Blumea s. str.

Palynotaxonomy of Calea sect. Meyeria (Asteraceae: Neurolaeneae)

Calea comprises 157 species that occur in the Neotropics. The genus is organized into eight subgenera and 18 sections. Calea sect. Meyeria consists of eight species occurring exclusively in south-central Brazil. In this study, pollen grains from these eight species were sampled from herborized flower buds in pre-anthesis. Pollen samples were acetolyzed, measured, and photographed under a light microscope. Unacetolyzed pollen grains were examined under a scanning electron microscope. The results were used to characterize pollen morphology and construct a palynotaxonomic key for Calea sect. Meyeria. The analyzed pollen grains were monads, isopolar, usually medium-sized, oblate spheroidal, tricolporate, with lalongate endoaperture, the sexine echinate and thicker than the nexine, and six spines in the apocolpium region. The eight species have very similar pollen grains, but some characters are informative for this section, namely pollen size, polar area, sexine ornamentation, and endoaperture characteristics. Despite the similarity of the pollen grains, palynological analysis was able to contribute to the delimitation of Calea species, providing new information for species distinction within Calea sect. Meyeria.

Pollen morphology and its taxonomic significance in Iranian Colchicum (Colchicaceae)

Pollen morphology of 15 species of Colchicum was studied using light microscopy (LM) and scanning electron microscopy (SEM). The results revealed considerable pollen character variation among the studied species, which provides helpful data for species delimitation in Colchicum. The pollen grains are monad, bilateral symmetrical, isopolar to subisopolar, prolate, perprolate, subprolate and oblate spheroidal and medium to large in size. The outline of pollen grains varies from circular to tetragonal from polar view and elliptical from equatorial view; it is dicolpate, tetrazonoporate or diporate. The results showed five types of sexine ornamentation. The current study demonstrates that the pollen morphological characters are significant in taxonomic classification of the Colchicum and provide valuable information for species identification. We performed multivariate analysis to assess the possible contribution of palynological data to the species relationships. The results of cluster and principal component analysis demonstrated a close relationship among the studied species.

Palynology of Philippine Amorphophallus Blume ex Decne. (Araceae) and its taxonomic implications

Abstract. Fontarum-Bulawin NF, Medecilo-Guiang MMP, Calaramo MA, Alejandro GJD. 2023. Palynology of Philippine Amorphophallus Blume ex Decne. (Araceae) and its taxonomic implications. Biodiversitas 24: 4095-4109. Amorphophallus is one of the genera of Araceae with diverse pollen characters. This study aimed to investigate the pollen morphological characters of Amorphophallus in the Philippines for inferring taxonomical relationships. Light microscopy (LM) and scanning electron microscopy (SEM) were employed to investigate pollen morphology of 14 accessions of Amorphophallus. Both acetolyzed and unacetolyzed pollens were studied to compare the outward aspect of pollens and the pollen characters were subjected to cluster analysis. Results revealed that pollen grains were mostly spheroidal, prolate-spheroidal, and subspheroidal in shape. The pollen sizes vary from 3.0 to 50 µm and exhibit very small to medium sizes. The ornamentations of unacetolyzed pollens were psilate and striate, whereas ornamentations in acetolyzed pollens are varied from psilate, rugulate, rugulate hamulate, reticulate, scabrate, striateto verrucate ornamentations. All pollens were inaperturate and monad. Cluster analysis using Euclidean generated 2 major clusters, namely Cluster I consists of Amorphophallus adamsensis Magtoto, Mones, Ballada, Austria, R.M.Dizon, Alangui, Regina, Amorphophallus sp.3 (Samar), Amorphophallus yaoi A.Galloway, Hett. &amp; Medecilo, Amorphophallus flammeus Calaramo, Batuyong, Bulawin &amp; Alejandro, Amorphophallus urceolatus Hett. et al. (Ilocos), Amorphophallus rayongii Hett. &amp; Medecilo, Amorphophallus sp.2 (Romblon), and Amorphophallus urceolatus Hett., A.Galloway &amp; Medecilo (Cavite); and cluster 2 consists of Amorphophallus paeoniifolius (Dennst.) Nicolson, Amorphophallus fontarumii Bulawin, Medecilo &amp; Alejandro, Amorphophallus rostratus Hett., Amorphophallus longispathaceus Engl.&amp; Gehrm., and Amorphophallus sp.1 Based on this study, pollen shape, size, and ornamentation can be used as supplemental characters for the taxonomic identification of Amorphophallus in the Philippines.

Effects of Fabaceae and Poaceae Pollen Accessibility and Traits on the Pollinivory of Adult Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae).

Pollen is a food source for adult Chrysoperla externa(Hagen), whose larvae are biocontrol agents against pests. However, adults may face challenges in foraging for pollen due to differences in pollen accessibility and variability in pollen morphology and chemistry. In the laboratory, we investigated the ability of adult C. externa to consume pollen from flowers of Cajanus cajan, Canavalia ensiformis, Crotalaria juncea, Flemingia macrophylla, Avena strigosa, Pennisetum glaucum, Sorghum bicolor, and Zea mays, and we explored whether adults chose any of these pollens based on their quantitative and qualitative features. Cajanus cajan and F. macrophylla pollen were the only ones not consumed by adults when confined to flowers. Pollen removed from the preanthesis buds was offered simultaneously for 24 and 48h. In both periods, adults consumed more of the medium-sized P. glaucum (with the second largest exine thickness) and large-sized Z. mays (with the thinnest exine) pollen, even though they had significantly less crude protein than Fabaceae pollen, whose sizes varied from medium (C. juncea, with the thickest exine) to large (C. ensiformis, whose exine thickness was equal to that of P. glaucum). Overall, adults consumed more Poaceae pollen than Fabaceae pollen, but the palynological features and the protein contents did not affect this choice. Our results highlighted that C. juncea, P. glaucum, S. bicolor and Z. mays are good pollen sources for adult C. externa and should be considered promising candidates in the selection of insectary plants to deploy in biocontrol programs aimed at the conservation of this lacewing.

Pollen morphology in the tribe Nigelleae (Ranunculaceae): a worldwide palynological investigation into the species

Pollen morphology in the tribe Nigelleae (Ranunculaceae): a worldwide palynological investigation into the species