Pollen Characters Research Articles

Pollen and trichome morphology of tribe Stachydeae (Lamiaceae) and its phylogenetic significance

Tribe Stachydeae with 12 genera were divided into two major clades: Melitis and Eurystachys clades consisting of all genera attributed to Stachydeae except Melittis. Recently, a broadly defined Eurystachys clade falling into 12 well-supported clades have been formally named in a phylogenetic nomenclature. In the present study, trichomes of 70 spp. from nine genera and pollens of 53 spp. from six genera were investigated using scanning electron microscopy (SEM) in order to draw the taxonomic conclusion of tribe Stachydeae. Trichome characters that can provide adequate variation in delimitation of taxa were: presence or absence of glandular or nonglandular trichomes, number of cells (uni-/bi-/multicellular), presence of extremely long trichomes (i.e. more than 1000 ?m), presence of branched trichomes as well as type of glandular trichomes (peltate or capitate with three subtypes: sessile to subsessile, short-stalked and long stalked trichomes). Among the investigated characters, extremely long simple trichomes and branched trichomes were apomorphic and were found in Eriostomum and Marrubiastrum clades, respectively. In addition, number of colpi, type of sculpturing as well as shape of lumina as the main features of the investigated pollen grains afforded valuable characters especially in delimitation of several natural groups, i.e. Eriostomum clade, Empedoclea clade, Sideritis clade, Marrubiastrum clade, and Swainsoniana clade. Moreover, a close relationship among two annual clades of Sideritis each of represents a section, i.e. Hesiodia and Burgsdorfia, is suggested by our results. However, in both Stachys and Olisia clades which are morphologically heterogeneous, type of sculpturing shows variation and mostly useful in species discrimination. Overall, trichome and pollen characters can be useful in describing the natural groups within tribe Stachydeae along with other reliable morphological characters.

Importance of palynology in the taxonomy of Piptolepis Sch.Bip. (Asteraceae: Lychnophorinae), a genus endemic to Brazil.

Lychnophorinae comprises 19 genera and 117 species. Its representatives are found mostly in the rocky grasslands ("campos rupestres") of Minas Gerais, Bahia, and Goiás States, Brazil. This study presents a palynological investigation of 10 species belonging to the genus Piptolepis, endemic to the rocky grasslands of the Espinhaço Mountains, in Minas Gerais State. The plant material used in this investigation was obtained from specimens deposited in Brazilian herbaria. Pollen grains were processed by the acetolysis method, measured, described, and photomicrographed in light microscopy and scanning electron microscopy. Morphological observations revealed Piptolepis pollen to be large, prolate spheroidal in most species, 3-colporate, ectoapertures long, sexine subechinolophate or sublophate. Endoapertures vary from almost circular, lalongate or lalongate, with a median constriction observed only in three species. Three types of spines were identified: prostrate and disorganized, elongated and narrow, and conical, erect, apex acute in the other species. This first palynological study of Piptolepis species allowed the separation of representatives of the genus using pollen keys. The most significant characters were pollen shape, ornamentation, endoaperture, and presence of median constriction in the endoaperture. The findings presented here do not support the infrageneric classification of Piptolepis, as pollen characters were not unique to any section.

Pollen morphology of Galactia P. Browne and related genera (Papilionoideae, Leguminosae), with emphasis on Brazilian representatives

Galactia is a pantropical genus, which is part of the Galactia clade, and together with the genera Betencourtia, Caetangil, Cerradicola, Collaea, Lackeya, Nanogalactia, and Rhodopis, it maintains a taxonomic relationship that has already been the focus of previous studies. However, the palynology of these groups has not been extensively studied, with gaps in pollen descriptions. Thus, a palynological study of 30 species belonging to Galactia and related genera was performed. For this purpose, pollen grains were acetolized using the standard methodology, subjected to scanning electron microscopy analysis, and then quantitatively and qualitatively evaluated. Generally, pollen grains of this genera are medium or large size, isopolar or heteropolar, 3-colporate, and may have microreticulate or reticulate exine. Pollen data for Rhodopis and Nanogalactia agree with the most recently proposed circumscription of these genera. Other genera exhibited similar pollen characteristics; however, the diameter of the lumen, associated with other pollen characteristics, proved to be important for the differentiation of the genera. Thus, the pollen morphology provided information that contributes to the description of the genera, mainly Brazilian representatives of Galactia and related genera.

A new combination of Strobilanthes (Acanthaceae) with two new records from Thailand

Strobilanthes spirei is proposed as a new combination of Clinacanthus spirei. Strobilanthes hypomalla and S. spirei are newly recorded for Thailand. The lectotypification of S. hypomalla is made. A detailed description of morphology and pollen features is provided as well as photographs, distribution map, ecology and taxonomic notes.

THE BEHAVIOR OF BEES IN BEE POLLEN COLLECTING

Introduction. Among the many issues of breeding and housing of honey bees we dedicated our studies to one of the topical issues that determines the growth and development of the bee colony– protein food. The goal of the work. To conduct a comprehensive study of the behavior of bees in bee pollen collecting. Materials and methods of research. The study was conducted on the experimental apiary of the National Scientific Center “Institute of beekeeping named after P.I. Prokopovych” in standard bee colonies of Ukrainian steppe breed (Apis mellifera sossimai). The bee colonies met the standard of Ukrainian steppe breed, as confirmed by the results of the exterior evaluation. Results of research and discussion. The use of protein food influences the physiological development and contributes to life extension of young bees. In deficiency of the protein food bees start slowly developing hypopharyngeal glands and therefore the level of feeding of larvae decreases. Conclusions and prospects for further research. The study revealed that bees-collectors of bee pollen have individual characteristics of bee pollen collecting which are reflected in difference between the time spent on bee pollen collecting, nature of the food collecting and activity of flying for food.

Pollen morphology of the Sapotaceae from Thailand and its taxonomic implications

The external pollen morphology of the family Sapotaceae in Thailand was examined using the acetolysis method to determine its taxonomic significance. Pollen of 39 specimens belonging to 32 species was investigated by means of light and scanning electron microscopy. Pollen grains are found to be monads, isopolar, colporate, lalongate, and variable in size, shape, aperture number, colpus length and exine thickness. Exine ornamentation is also variable, showing more than one pattern on a single pollen grain. Principal component analysis based on 13 pollen characters identified three pollen groups: Chrysophyllum, Madhuca and Pouteria types based on pollen shape, size, the ratio of colpus length to the polar axis and exine sculpturing. Pollen morphology is taxonomically useful in the classification of the Thai Sapotaceae, especially in the taxonomic status of Planchonella and Pouteria species.

Palynological analysis some species of Chenopodiaceae and its systematic implications using scanning electron microscopy

Chenopodiaceae is a large, diverse and cosmopolitan family within the order Carophyllales. The majority of Chenopodiaceae species are adapted to saline, hypersaline, xerophytic and xerohalophytic communities or ruderal habitats. The family Chenopodiaceae is stenopolinous the pollen grains are monad and exclusively polypantoporate with tiny spinules on both tectum and operculum. Pollen morphology of six genera of Chenopodiaceae (Seidlitzia, Atriplex, Bassia, Salsola, Krascheninnikovia and Spinacia) have been studied in details. These plant species were collected from different phytogeographical regions of Iran. The palynological investigation was done using scanning electron microscopy (SEM) techniques. Pollen characters studied in this study include pollen and pore diameters, number and density of apertures, interporal distance (chord), chord/pollen diameter ratio, pore diameter/pollen diameter ratio as well as spinule density on tectum and operculum. We used different multivariate statistical methods to reveal the species relationships. Ward clustering analyses have been done to check out the relationship among the species. The shapes of pollen grains were radially symmetrical, isopolar, pantopolyporate and spheroidal. Their exine structure is similar. In the Chenopodiaceae, three pollen types have been defined, mainly on the basis of pollen grain size, pore number, number of microechinae on pore membrane, the density of spinules, and pore edge shape.

Differences in flowering and pollination characteristics of two gender phenotypes of <i>Lilium concolor</i> var. <i>megalanthum</i> between two habitats

Differences in flowering and pollination characteristics of two gender phenotypes of <i>Lilium concolor</i> var. <i>megalanthum</i> between two habitats

Comparative pollen morphology and its systematic implications in Resedaceae in Iran

The pollen morphology of Resedaceae in Iran has been studied using light and scanning electron microscopy and described in detail for the first time. Although most of the species had prolate or perprolate pollen grains, variation was observed in other diagnostic pollen characters. Based on exine ornamentation, the pollen grains could be divided into six main types: reticulate, macroreticulate, microreticulate, reticulate‐striate, rugulate and perforate, and eight subtypes. In addition, the studied species varied in pollen size, shape in equatorial and polar views, aperture features and ornamentation, representing Resedaceae as a eurypalynous family. The largest pollen grains belonged to Reseda lutea L., while R. aucheri subsp. rotundifolia (Kotschy ex Müll.Arg.) Rech.f. had the smallest ones. Furthermore, species of Ochradenus, Oligomeris and Reseda showed diagnostic palynological characteristics that may provide a better understanding of the taxonomy of Resedaceae. A dichotomous key based on pollen morphology to the 27 Resedaceae taxa native to Iran are also presented.

Palynological analysis of genus Geranium (Geraniaceae) and its systematic implications using scanning electron microscopy

Pollen morphology of 23 species belonging to Geranium have been studied in details, which represent eight sections of two subgenera i.e., G. sect. Dissecta, Geranium, and Tuberosa of subgen. Geranium, Divaricata, Lucida, Ruberta and Trilopha of subgen. Robertium. These plant species were collected from different phytogeographical regions of Iran. The palynological investigation was done using scanning electron microscopy (SEM) techniques. Different palyno-morphological features have been observed, and the closely related species were distinguished. We used different multivariate statistical methods to reveal the species relationships. Ward clustering analyses have been done to check out the relationship among the species. The shapes of pollen grains were monad, radially symmetric, isopolar, apertures were tricolporate, and of spheroid, prolate-spheroid or sub-prolate classes. Three pollen types were recognized on the basis of differences in exine sculpturing pattern: reticulate-clavate, striate-rugulate, reticulum cristatum with clavae. Observed differences were not of diagnostic importance in subgenera and sections level. The main objective of this study is to find distinguish pollen characters in the species of the genus Geranium and to elucidate their systematics importance.

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 31.3μm ±1 to 17.5μm ±1.4 and equatorial axis size (E) varies from 22.2μm ±1.8 to 13.1μm ±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.

Comparative pollen morphology of the Kirengeshoma (Hydrangeaceae)

The genus Kirengeshoma, in the family Hydrangeaceae, is considered by some botanists to be monotypic while others divide it into two species, K. palmata, native to Japan and China, and K. koreana, native to South Korea. We have conducted a comparative pollen morphological study of five populations of the two putative species to investigate this question. Pollen morphological characteristics were observed with scanning and transmission electron microscopy. The pollen characteristics of all five populations were similar. All populations dispersed pollen as the monad and the pollen grain shape were either spheroidal or sub-spheroidal and approximately 12 to 18 µm in diameter, falling in the small grain category. In all five populations, the pollen grains were iso-polar and radio-symmetrical, with tri-colporate apertures. Additionally, pollen surface sculpture patterns of all populations were semi-tectate and reticulate. As a result, the two putative species differed in that the pollen grains of K. palmata were smaller, and their endexine slightly thicker, than those of K. koreana. Despite these differences, we conclude that the similar pollen morphology of all the populations does not support separating them into two independent species. However, different species of angiosperms often have similar pollen morphology. Therefore, we suggest that the genus should be considered to consist of these two independent species unless further morphological or molecular evidence to the contrary is forthcoming.

Taxonomic implications of pollen of some species of the genus Pterospermum Schreb. (Malvaceae s.l. subfam. Dombeyoideae)

A palynological study of six species of Pterospermum was conducted to investigate variation in pollen micromorphological characteristics. The studied species were P. diversifolium, P. elongatum, P. jackianum, P. javanicum, P. lanceifolium and P. subpeltatum. Pollen was subjected to acetolysis, single-grain techniques and dehydration series, and observed using light and scanning electron microscopy. The results reveal some common characters shared by all the studied species, namely: echinate-granulate exine ornamentation; porate pollen class; and circular amb. Variation was found in the ratio of exine thickness, pollen size, and average spine length, outline, shape, measurements, spine size and the presence of an annulus. These characters proved to be valuable for identifying and differentiating the studied species. This study shows that morphological characteristics of Pterospermum pollen have taxonomic value, especially for the identification and differentiation of species of the subfamily Dombeyoideae and even other Malvaceae s.l.

Pollen morphology and its taxonomic potential in some selected taxa of Caesalpiniaceae observed under light microscopy and scanning electron microscopy.

Pollen micromorphology is not only used to check the functional and structural evolution in plants but also to solve the taxonomic problem related to the classification of plants. Therefore, keeping in view the significance of pollen traits, selected taxa of the subfamily Caesalpiniaceae was collected from different geographical regions of Pakistan. The species were then analyzed under both light microscopy and scanning electron microscopy techniques to investigate the importance of micromorphological characters of pollen in the identification and classification of species. Great variation was recorded in equatorial shape, surface ornamentation, tectum, polar diameter, equatorial diameter, and exine thickness. However, little variation was observed in pollen type, polar shape, and fertility of pollen. The equatorial shape of five types was observed: prolate, prolate-spheroidal, spheroidal-subprolate, subspheroidal-prolate, and subspheroidal. Four types of surface ornamentation, psilate, granulate, clavate, and perforate, were recorded. Tectum of five types, intactate, reticulate regulate, medium reticulate, tactate, and striate, was observed. Sexine was thicker than nexine in all studied species. The largest polar diameter was observed in Caesalpinia pulcherrima 64.1 μm while the smallest in Parkinsonia aculeata 26.1 μm. The largest equatorial diameter was found in C. pulcherrima of 70.25 μm whereas the smallest in P. aculeata 27.57 μm. All the pollens analyzed were tricolporate. All studied species have a fertility ratio of more than 90%. A taxonomic key was developed to show the variation in pollen features and delimit species for the correct identification. In conclusion, the pollen traits were found useful to define species boundaries at various taxonomic ranks and will strengthen the taxonomy of this subfamily. Besides, this study also explored the palynological traits and their implication in the taxonomy of the subfamily Caesalpiniaceae.

Palyno-morphological attributes of some selected plant species of family Asteraceae from district Dera Ismail Khan, KPK, Pakistan.

The current study aimed to investigate the palyno-morphological features of Asteraceous species from District Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan. A total of 13 species were collected, pressed, identified, and examined by using light and scanning electron microscopy. Both qualitative and quantitative pollen characters were observed, that is, equatorial and polar diameter, number of pores and colpi, exine thickness, exine sculpturing, pollen shape, and P/E ratio. Pollen shapes observed in studied taxa were spheroidal, suboblate, oblate-spheroidal, and lophate-spheroidal. The aperturation patterns of pollens vary from tricolporate to tetracolporate. The maximum polar and equatorial diameter of 75-100 (87.5 ± 13.6) μm and 87.5-117.5 (102.5 ± 16.4) μm, respectively, was recorded in Echinops echinatus, while minimum polar and equatorial diameter of 20-22.5 (21 ± 1.36) μm and 22.5-25 (23.5 ± 1.36) μm, respectively, was recorded in Aster subulatus. Six types of exine sculpturing patterns were observed; echinate, micro-echinate, echinate-microreticulate, microreticulate, echinate-perforate, and scabrate. Maximum exine thickness of 8.75 μm was recorded in E. echinatus and minimum of 1.25 μm in Launaea mucronata. The pollen morphology has valuable significance in understanding the taxonomy of different plant groups and plays a central role in the correct identification and classification of Asteraceous flora at species, generic, and tribe levels.

POLLEN MORPHOLOGY OF LYCIUM (SOLANACEAE) SPECIES IN IRAN

Lycium (Solanaceae) has more than 100 species in arid and semi-arid parts of the world. In Iran, this medicinal plant is represented by 6 species, on which no palynological study has been conducted. Pollen morphology of 7 taxa are considered for the first time to evaluate the species relationships based on palynological data. Observations were made by use of Scanning electron microscopy on untreated pollen grains. Multivariate statistical analyses were carried out for qualitative and quantitative pollen features in the species studied. Results show that all pollen grains were monad, isopolar, zonotricolporate in prolate and preprolate shape. Exine sculpture was of striate and regulate patterns. Variations in pollen grains are considered to overcome the identification problems in species separation in morphologically similar taxa in this genus in Iran. The importance of pollen features in delimitation in some genera of Solanaceae was previously proven and the present study elucidates that some features as exine sculpture and some quantitative characters are of diagnostic importance in Lycium species native to Iran.

Pollen morphology of Ellisiophyllum and Sibthorpia (Plantaginaceae, tribe Sibthorpieae) and phylogenetics of the tribe

Pollen morphology of six species belonging to genera Ellisiophyllum and Sibthorpia (Plantaginaceae tribe Sibthorpieae) was studied using light and scanning electron microscopy. The data were analyzed in the light of the first phylogenetic analysis including all but one species of the tribe using DNA sequence data from nuclear ribosomal (ITS) and plastid trnL-F region. Pollen grains in representatives of this tribe are 3-colpate, occasionally 3-porate, suboblate to prolate; mainly medium-sized, rarely small. One major pollen type (3-colpate) is recognized in the tribe. Within this pollen type, six subtypes are distinguished based on their exine sculpture, pollen grain size, length of the apertures, and exine thickness. The obtained results confirm that pollen characters are useful for species identification. Palynomorphological data are consistent with the results of the molecular phylogenetic analyses. All studies support a sister relationship of the widespread European Sibthorpia europaea with the widespread South American Sibthorpia repens and a sister relationship of two insular species, the Balearic Sibthorpia africana and the Madeiran Sibthorpia peregrina. Pollen grains in the tribe Sibthorpieae have both reticulate exine sculpture characteristic for representatives of the Russelieae–Cheloneae–Antirrhineae clades of Plantaginaceae, and also nanoechinate sculpture, which is typical for the Veroniceae and Plantagineae clades of that family. Also, in Sibthorpia repens, we observe a possible transition from the colpate type to the porate type typical for taxa of Plantago and Littorella.

The comparative study of Alkanna and Huynhia (Boraginaceae, Lithospermeae), with description of a new species in Iran

A new blue to light violet-flowered species from SW Iran is described as Alkanna semiromica. The new species is morphologically close to A. frigida and Huynhia pulchra. Floral characters suggested the affinity of the new species to Huynhia, especially the stamens inserted at different heights in the corolla tube and also the plant trichomes while the pollen characters supported its place within the genus Alkanna. A comparison with the new species and the most similar genera is presented here based on new and old morphological data, to understand the differences among the species. In addition, the diagnostic characters, description, detailed illustrations, and taxonomic comments are presented.

Pollen analysis of representatives of the tribes Ampelopsideae, Cayratieae and Parthenocisseae and evolutionary history of Vitaceae genera

The family Vitaceae has a wide distribution, occurring in temperate, subtropical, and tropical climates. Vine members of the family thrive in different types of vegetation. Currently, the family includes five recognized tribes: Ampelopsideae, Cisseae, Cayratieae, Parthenocisseae, and Viteae. This study describes the pollen morphology of representatives of Ampelopsideae, Cayratieae, and Parthenocisseae. The other tribes are not described because they have been the subject of previous studies. The aim was to assess the relationships among the five tribes using multivariate analysis and to reconstruct the evolution of pollen characters using existing phylogenetic hypotheses. Specimens representing the three tribes were obtained from herbaria, treated by the acetolysis method, measured, photographed, and described using light and scanning electron microscopy. Results showed that pollen grains are medium (25–50 µm) in size, isopolar, tricolporate, and subprolate to prolate. Ornamentation varies between species. Multivariate analysis was based on quantitative characters, of which pollen diameters, apocolpium side, and polar area index were the most significant. Tracing of pollen characters showed that size, shape, and ornamentation are an evolutionary trend within the family. This investigation expands the palynological knowledge on representatives of Vitaceae tribes, contributing to future palynotaxonomic and evolutionary studies.

Morphological differences between anemophilous and entomophilous pollen.

In order to provide a palynological guide for the identification of insect-carrying pollen grains, we studied the pollen grains of 10 anemophilous species and 10 entomophilous species in the Beijing urban area using light and scanning electron microscopies. We found that anemophilous pollen grains are small, spheroidal, or oblate spheroidal, while entomophilous pollen grains are medium and oblate. Comparison of the exine thickness and surface ornamentation showed that anemophilous pollen grains have significantly thinner exine and smoother surface ornamentation than entomophilous pollen grains. The results also revealed pollen characteristics adaptive to different pollination types. Overall, our study indicated that pollen morphology might be helpful for preliminary identification of anemophilous and entomophilous pollen.