Practical and cost-effective method for the isolation of pollen grains from various sources

The great micromorphological diversity of pollen grains amongst the seed plants is not only a marvel of nature but also a significant tool for plant biologists, especially taxonomists and ecologists. However, with the staggering diversity comes the problem of setting up a consistent and useful terminology to cope with classifying such morphological features. As the authors of this book state, although such categorization is rather artificial it is essential for defining the range of morphological diversity and generating systematic order. The remit of this illustrated handbook of pollen terminology is to provide a collection of the most useful and important terms in palynology and illustrate them by light and electron microscope micrographs. Essentially, this handbook is an updated and beautifully illustrated version of the web-accessible ‘Glossary of pollen and spore terminology’ (Punt et al., 2007). The largest proportion of the handbook is devoted to an illustrated glossary of pollen-related terms, which is usefully split into several parts. These cover the terminology of pollen units, pollen class, shape and size, apertures, ornamentation, the pollen wall and a miscellany of other terms. This glossary section has been produced to high standards, with an excellent lay-out and organization. Every term is exceptionally illustrated, not by just one but by several micrographs, with light, SEM and TEM figures used where appropriate. Usefully, an alphabetical text version of the glossary is included at the back, making it even easier to track down and define palynological terms. Although the glossary alone is comprehensive, copiously illustrated and user-friendly enough to recommend this volume in its own right, the value of this work is enhanced by a series of short, general chapters that cover palynology and its history, an introduction to pollen morphology, a discussion of why categorization is required and an overview of pollen development. From a more practical perspective, the chapters that cover pollen features that can be misinterpreted, controversial or fuzzy terms and methods are particularly valuable. Whilst this volume will be an essential addition to reference libraries, there is no doubt that it will make a regularly consulted addition to the shelves of individuals involved in studying pollen, from those working in palaeobiology, ecology, entomology and plant systematics through to forensic scientists. Using this volume will simplify the procedure of describing pollen morphology from samples under study. Indeed, this volume would have great value in practical classes for students where pollen, pollen morphology and pollination biology is the subject of investigation. Although the authors clearly state that this handbook is not meant to be an exhaustive treatment of the subject, one or two additions would have further enhanced this attractive and practical book. In a few places, notably in the glossary of miscellaneous terms, the labelling in the illustrations of the feature being defined is inadequate, confusing or absent. For example, for tapetum in the glossary (p. 216) the TEM micrographs do not actually label the tapetal layers. The chapter on pollen development could be improved, with a diagram to explain the sporophytic lineage of cells in anther development leading to pollen formation via meiosis. The statement that ‘gametogenesis starts with formation of a central vacuole within the uninucleate microspore’ is both confusing and inaccurate. Strictly, gametogenesis is associated with the second pollen mitosis of the generative cell. Perhaps the most significant omission in this volume is a focused discussion concerning the use of pollen micromorphology in plant systematics. It would have been interesting and informative to discuss particular morphological and developmental features from a phylogenetic perspective. For instance, for each morphological feature an outline of the known pattern of distribution amongst seed plants would have been useful. There is also almost no mention of whether these strikingly different microscopic features are associated with biologically important phenomena, such as the mode of pollen dispersal, the type of stigmatic surface or manner of pollen germination. This kind of discussion would allow a much greater appreciation of which features of the pollen grain are of adaptive value and which have minimal selective value. Without so much as a limited comment of this kind, even if speculative in nature, the diversity of morphological features that are so well illustrated in this handbook become rather abstract and meaningless. Although there are a few shortcomings, this handbook is not only of practical use but also exceptionally well-crafted and a delight to the eye. In the age of online resources, it emphatically demonstrates that well-produced reference books can be superior to web-based material. I have no doubt that this will become an indispensable standard reference work for all scientists studying pollen.

Soil properties influence various aspects of plant growth, development and reproduction. Despite the importance of the gametophytic phase in the plant life cycle, its response to soil factors remains poorly understood, particularly in wild plants. This study showed intraspecific variability of pollen morphology in Staphylea pinnata L., with its response to physicochemical soil properties examined under natural conditions in forest ecosystems. Staphylea pinnata is a locally rare species in Central Europe and is considered to be a shrub that prefers carbonate soils. The pollen of S. pinnata was sampled from 55 natural sites at the northern edge of its geographical range. Eleven morphological features in a total of 1620 pollen grains were analysed in relation to 15 soil parameters. The main objective was to establish a link between the habitat conditions, particularly contents of selected elements in the soil, and pollen grain morphology. Our results indicate a potential influence of Cu, Zn, and CaCO₃ on pollen morphology in S. pinnata. The interaction between pollen morphology and these three nutrients was manifested in pollen size, shape, and exine thickness. We show that in the wild, exine thickness (Ex) is positively correlated with CaCO₃ content. In addition, the length of the polar axis (P) and equatorial diameter (E) are correlated with Cu, while the P/E ratio - with Zn contents, respectively. Our results suggest that these ions play an important role in the formation of pollen grains. There is a lack of research linking the morphological features of pollen grains with such environmental parameters as nutrient contents. This study provides evidence for the role of soil micronutrients in shaping pollen morphology. This is the first comprehensive analysis linking wild soil chemistry and natural pollen variation in a rare European species. Further research should focus on the relationship between the mineral contents in the soil, contents of individual elements in pollen grains, pollen viability, as well as selected plant physiological parameters, such as photosynthetic activity. This will provide insight into the role of each element and the physiological state of the plant in the formation of mature pollen grains under natural conditions.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-14136-3.

Pollen Morphology of the Genus Erythrina (Leguminosae: Papilionoideae) in Relation to Floral Structure and Pollinators

The Pollen grains are the male reproductive units of many types of plants. They vary in shape and ornamentation. The Morphology of pollen grains can be used for distinguishing species and cultivar in tree fruit species. Pollen morphology has been effectively applied in solving several problem of taxonomy. Pollen morphology also can be applied for various area, such as evolutionary studies, allergy studies, melissopalynology, forensic science, tracing plant geography, geology, climate change studies and study of past human impact on vegetation. Pollen morphology can be used for identification species. In this study, ultrastructure of pollen morphology of Kopsia pauciflora Hook.f. var. Pauciflora in Purwodadi Botanic Garden, was investigated using scanning electron microscope. Several morphological parameters including symetry, shape, size, aperture, also ornamentation shape. The type of pollen grains are monads, isopolar, sized 69.40 µm - 80.08 µm x 42.71 µm - 50.72 µm, shape prolate (P/E E 1.61-1.76). Their apertures are tricolporate. Pollen infolding, interaperture area sunken. The ornamentation is perforate.

Abstract. Danila JS, Alejandro GJD. 2020. Pollen morphology and infrageneric classification of selected Callicarpa species (Lamiaceae) from the Philippines and Borneo. Biodiversitas 21: 5736-5746. We used pollen grains of ten species representing the controversial genera Geunsia Blume and Callicarpa L. from the key centers of Malesia - Philippines, and Borneo including other countries in Asia. Herbarium specimens and collected samples from the field were examined using Scanning Electron Microscopy (SEM) in search of new characters to establish conclusive evidence that might contribute to the study of the relationship between Geunsia and Callicarpa. Based on SEM observations, both the investigated pollen grains of Geunsia and Callicarpa are mostly small to medium, spheroidal or circular, prolate to oblate, isopolar, and tricolpate. Moreover, the exine surface is mostly coarsely reticulated with a thin perforated colpus edge and sunken finely granulated colpus membrane. However, exine ornamentation shows possible separation of Geunsia and Callicarpa due to various morphological results observed. Several types of exine ornamentation were found in species of the section Callicarpa, i.e., C. erioclona, C. arborea, C. macrophylla, and C. candicans which attributes in the projected separation of these species while four species in the section Geunsia are united as a group having coarsely reticulate exine. Surprisingly, C. arborea samples give additional support to the hypothesis that rugulate exine sculpture might be its plesiomorphic character due to evolutionary evidence of other exine types of this species. On the other hand, pollen size and shape class of the sections of Geunsia and Callicarpa were both observed with similar features having an average pollen size equivalent to medium and a prolate shape supporting the concept of previous studies to nest Geunsia within Callicarpa. This reveals that pollen morphology is useful in the study of infrageneric classification within these groups. However, further morphological studies involving larger number of specimens are needed especially in the study of exine to prove its consistency as diagnostic character in the study of phylogenetic relationship.

Identification of pollen grains of cultivated plants is essential in archaeobotanical studies. In this study, we investigated the pollen morphology of 30 species which are representatives of most of the crop plants in southern China, using a light microscope. Our results show that the pollen grains of these species or genera can generally be identified by their size, aperture(s) and exine sculpture. We found that: (1) some cultivated cereals can be distinguished from wild species of Poaceae according to their size frequency combined with their morphological features; (2) the lengths of the equatorial diameter (E), polar axis (P) and the greatest dimension of the lumina (the size of the network sculpturing) of the exine reticulum may be diagnostic features to distinguish some brassicaceous vegetables. There are significant differences between the E and P values among Brassica campestris (B. rapa, oilseed rape, Chinese cabbage), B. alboglabra (B. oleracea var. alboglabra, gai lan, Chinese kale), B. parachinensis (B. rapa var. parachinensis, choy sum, Chinese flowering cabbage) and B. chinensis (B. rapa ssp. chinensis, pak choi), but moderate differences in the longer axis length of the reticulum lumina, which provide potential for identifying species on the basis of pollen grains. We compared the P values and the longer axis length of the lumina of modern specimens of Brassicaceae pollen grains with those of fossil pollen extracted from the Ming-Qing cultural layer in the Fuqikou site at Chongqing, China, and found that the fossil pollen grains of Brassicaceae probably represent vegetable plants related to B. parachinensis. Moreover, we measured the diameters of rice pollen grains from modern paddy fields to assess the pollen size frequency and found that the size range from ~ 34 to 38 µm is closely associated with rice pollen in southern China, which can be used to detect pollen signals of human activities in archaeobotanical investigations.

Modern agricultural biotechnologies, such as those derived from genetic modification, are solutions that can enable an increase in food production, lead to more efficient use of natural resources, and promote environmental impact reduction. Crops with altered genetic materials have been extensively subjected to safety assessments to fulfill regulatory requirements prior to commercialization. The Brazilian National Technical Biosafety Commission (CTNBio) provides provisions for commercial release of transgenic crops in Brazil, including requiring information on pollen dispersion ability as part of environmental risk assessment, which includes pollen viability and morphology studies. Here we present the pollen viability and morphology of non-transgenic conventional materials, single-event genetically modified (GM) products, and stacked GM products from soybean, maize and cotton cultivated in Brazil. Microscopical observation of stained pollen grain was conducted to determine the percentage of pollen viability as well as pollen morphology, which is assessed by measuring pollen grain diameter. The pollen viability and diameter of GM soybean, maize and cotton, evaluated across a number of GM events in each crop, were similar to the conventional non-GM counterparts. Pollen characterization data contributed to the detailed phenotypic description of GM crops, supporting the conclusion that the studied events were not fundamentally different from the conventional control.

Pollen morphology, involving the physical characteristics of pollen grains from seed plants during reproduction, plays an important role in plant biology, ecology, and evolution. High pollen concentrations in the air can degrade air quality and exacerbate respiratory conditions such as asthma. Understanding pollen morphology and its implications for air quality is significant for mitigating respiratory health risks. Conventionally, fluorescence microscopy is used for pollen imaging, but photobleaching, quenching, and phototoxicity affect the surface morphology and do not provide quantitative data on the pollen grains. For this study, we used bright field (BF) imaging and quantitative phase imaging (QPI), a label-free interferometric microscopy method, to look at differences in the shape of pollen. BF imaging provides information about the shape and size of the different pollens but has a limitation of low contrast. To obtain high-contrast images and quantitative data on the pollen grains without any exogenous agents, we employed QPI and BF imaging in the present study. QPI enables the extraction of detailed information regarding the cell wall, aperture, and thickness of pollen while also maintaining their natural state without the need for chemical treatments. In the present work, we sampled the ambient air from May 2023 to January 2024 on the IIT Delhi campus. Subsequently, QPI and BF imaging have been done for pollen identification and phase analysis of arboreal and non-arboreal pollen. Further, by utilizing the information obtained from BF microscopy and QPI, different species of pollen have been identified, and a pollen calendar has been prepared for exhibiting pollen season throughout the year. To the best of the authors’ knowledge, they have conducted the QPI of airborne pollen grains for the first time; this technique holds great potential for characterizing airborne pollens without the need for staining or sample preparation.

Gloxiniinae comprises herbs and subshrubs usually growing on rocky outcrops, rocky fields or gallery forests. For Gesneriaceae in some cases variations in pollen morphology allow the differentiation of genera and species. We studied the pollen grains of ten Brazilian species of Gloxiniinae (Gesneriaceae), including the genera Chautemsia, Gloxinia, Goyazia, Mandirola and Seemannia with the purposes of describing the pollen morphology of these genera, and contributing to the taxonomic characterization of the group and a better delimitation of genera and species of Gesneriaceae. The pollen grains were acetolyzed, measured, photographed and described qualitatively. Quantitative data were analyzed through descriptive and multivariate statistics. Non-acetolyzed pollen grains were observed in SEM and TEM in order to provide more details of the ornamentation and the structure of the exine. The analyzed species differ as to the pollen amb, shape, length, width and ends of colpi, presence or absence of margo, type of endoaperture and exine ornamentation. We found circular, subcircular and subtriangular amb, oblate spheroidal and subprolate shape, long or very long colpi, narrow, wide or very wide, with or without margo, lalongate or lolongate endoaperture in microreticulate or reticulate pollen grains. The reticulate ornamentation appears in the Gloxinia species’ pollen grains, and lolongate endoapertures represent the pattern for the subtribe pollen grains except in Chautemsia. The pollen grain metrics examined by principal component analysis allow generic distinction. We conclude that qualitative and quantitative pollen data help to delimit the genera and species of Gloxiniinae.

This research was conducted in May 2016 in RSUD dr. Kanujoso Djatiwibowo Balikpapan by using acetolysis method. This aims to determine the pollen morphology and determine the plant species that becomes the pollen source which triggers the ARI also determine the periodic calendar of otolaringology patients in RSUD dr. Kanujoso Djatiwibowo Balikpapan all the time. The pollen analysis results on a sample of ARI mucus patients in RSUD dr. Kanujoso Djatiwibowo Balikpapan, was found there are 4 plant species and 3 families. The plants which expected dominating as the pollen source that triggers ARI are from Cyperaceae family which is Scirpus lacustris, Gramineae family which are Oryza sativa and Saccharum spontaneum also Liliaceae family which is Lilium regale. Based on the pollen morphology (shape, size, ornament and aperture), pollens with monad unit dominate the sample. The pollen shape are various from prolate, oblate spheroidal, subprolate and oblate. Ornament type is psilate. Aperture consists of triporate, pantoporate and inaperture. Therefore, it can be stated that the species of pollen source that triggers ARI has pollen morphology which are simpler and small. Based on ARI patient data in RSUD dr. Kanujoso Djatiwibowo Balikpapan from 2013 to 2015 is known periodically appear at the end of the year to early next year and the ARI interference occurs at the beginning of the dry season (April - May).

Among the angiosperms, features of pollen morphology such as grain size, aperture number and surface ornamentation display striking variation. It is less well appreciated that pollen morphology may vary within and among populations of the same species as well as within individual plants. In some species, individual plants produce multiple types of fertile pollen grains (called pollen heteromorphism). Aspects of pollen morphology, such as aperture number, are likely to affect fertilization success with different morphologies favored in different local competitive and ecological environments. This study surveys variation in pollen grain morphology among species throughout the genus Thalictrum. Pollen from individuals of 36 species was rehydrated from herbarium specimens, and light microscopy was used to quantify pollen grain aperture number and size. I find that pollen aperture-number heteromorphism is present within all Thalictrum species studied, and distributions of aperture-number morphs vary both within and among species. This study provides an example of significant pollen heteromorphism within a genus that also varies widely for pollination mode and sexual system.

A Factor Analysis Study of the Functional Significance of Angiosperm Pollen

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.

Neste estudo, foi analisada a morfologia polínica de 11 espécies dos diferentes gêneros nativos florestais da família Poaceae do extremo sul do Brasil para averiguar se seus grãos de pólen são diferentes do pólen de gramíneas campestres dos ecossistemas da América do Sul. Embora grãos de pólen de gramíneas sejam relacionados à vegetação campestre quando identificados em sedimentos quaternários, algumas espécies dessa família são florestais e sua morfologia polínica é desconhecida para o sul do Brasil. Foram averiguadas diferenças entre os grãos de pólen florestais de Poaceae e o pólen de vegetação campestre dessa família já descrito para a região. Espécies florestais de Poaceae demonstraram grãos de pólen maiores do que os grãos de pólen de espécies campestres. Comparando-se os grãos de pólen dos diferentes gêneros florestais, podem-se distinguir dois padrões que estão relacionados ao tipo de hábito. Espécies florestais herbáceas apresentaram grãos de pólen menores que as espécies arbóreas que podem alcançar o estrato superior da floresta. As informações apresentadas indicam que é possível a distinção de padrões entre grãos de pólen de gramíneas florestais em relação ao hábito e que seus grãos podem ser distinguidos dos de espécies campestres em registros fósseis quaternários do sul da América do Sul.

Pollen morphology varies at inter- and intraspecific levels. Its interaction with pollinator behavior and morphology determines the probability of successful pollination. We tested whether pollen morphology promoting successful pollination differs depending on pollinator taxa in a generalist shrub, Weigela hortensis (Caprifoliaceae). We identified flower visitors carrying pollen from anthers to stigmas and compared the spine length and diameter of the pollen grains they carried. We found that pollen on the bodies of bumble bees and hunch-back flies and the scopae of small bees (including andrenid bees) contributed to seed production. Pollen grains on the bodies of bumble bees had longer spines than those on the scopae of andrenid bees or the bodies of hunch-back flies. Pollen grains on the bodies of bumble bees and the scopae of andrenid bees had larger diameters than those on hunch-back flies. Bumble bees collected pollen grains with shorter spines and larger diameters on their corbiculae while andrenid bees collected pollen grains with shorter spines and intermediate diameters on their scopae. The differences in morphology of pollen carried by pollinators reflected the tendency of bees to collect pollen with specific morphology into corbiculae/scopae. Our findings suggest that pollen morphology has diversified to facilitate successful pollination by pollinating partners.