Pollen Characters Research Articles

A new method based on physical patterns to impute aerobiological datasets.

Limited research has assessed the accuracy of imputation methods in aerobiological datasets. We conducted a simulation study to evaluate, for the first time, the effectiveness of Gappy Singular Value Decomposition (GSVD), a data-driven approach, comparing it with the moving mean interpolation, a statistical approach. Utilizing complete pollen data from two monitoring stations in northeastern Italy for 2022, we randomly generated missing data considering the combination of various proportions (5%, 10%, 25%) and gap lengths (3, 5, 7, 10 days). We imputed 4800 time series using the GSVD algorithm, specifically implemented for this study, and the moving mean algorithm of the "AeRobiology" R package. We assessed imputation accuracy by calculating the Root Mean Square Error and employed multiple linear regression models to identify factors independently affecting the error (e.g. pollen variability, simulation settings). The results showed that the GSVD was as good as the well-established moving mean method and demonstrated its strong generalization capabilities across different data types. However, the imputation error was primarily influenced by pollen characteristics and location, regardless of the imputation method used. High variability in pollen concentrations and the distribution of missing data negatively affected imputation accuracy. In conclusion, we introduced and tested a novel imputation method, demonstrating comparable performance to the statistical approach in aerobiological data reconstruction. These findings contribute to advancing aerobiological data analysis, highlighting the need for improving imputation methods.

Palynotaxonomy of Neotropical species of Paullinia L. (Sapindaceae)

Paullinia is the second-largest genus within the Sapindaceae, with approximately 200 species. It predominantly comprises lianas that inhabit humid forests, mainly the Amazon and Atlantic forests in Brazil. This study aimed to characterize the pollen morphology of 60 species of Paullinia, examining the potential of pollen characters as morphological markers to support the systematics of the genus. The pollen material was obtained from exsiccatae of flower buds from major herbaria. Pollen grains were acetolyzed, measured, described, and illustrated using light microscopy. Scanning electron microscopy was used for accurate descriptions of surface features. The analyzed characters included pollen shape, size, aperture type and number, and exine ornamentation. The similarity of pollen characters between species was analyzed using hierarchical cluster analysis and principal component analysis. The results showed that pollen grains of Paullinia species are shed in monads, heteropolar in most species and isopolar in some others, medium or large in size, oblate or suboblate, and 3- or 3-4-porate, with perforate sexine ornamentation in most species and microreticulate in some others. Multivariate analyses revealed that pollen morphology is informative and holds taxonomic potential, enabling grouping based on the similarity of the unique pollen characters of the genus. Species dispersion on the PCA biplot showed that the five clusters formed by HCA were robust, suggesting that quantitative and qualitative pollen characters exhibit consistency with regard to the similarity species. The palynological findings presented here contribute to enhancing our understanding of the morphological characters, aiding in the taxonomy and systematics of the genus.

IDENTIFIKASI DAN KARAKTERISTIK MORFOLOGI POLEN PAKAN KUPU-KUPU (IMAGO) DI JALUR WISATA GOA SAMPE MARTA KABUPATEN KUTAI KARTANEGARA KALIMANTAN TIMUR

ampe Marta Cave Tourism is located in Kutai National Park, Kutai Kartanegara Regency, East Kalimantan, and is one of the natural tourism areas with high biodiversity. The tourist route in this area offers natural beauty and a habitat that supports the lives of various butterfly species. This study aims to identify plants that are food sources (nectar) and non-nectar, types of butterflies, and the characteristics of pollen from each food plant. This study uses the transect method, namely taking samples of flowers and butterflies along the route, and the acetolysis method to see the morphological characteristics of pollen. The results of the study showed that there were 19 species from 11 families of nectar-eating plants identified as being utilized by butterflies (imago) as a source of nectar, where Ageratum conyzoides (Asteraceae), Asystasia gangetica (Family Acanthaceae), Leea indica (Family Vitaceae) were the dominant species that were often visited. In contrast, non-nectar feed such as minerals, rotten fruit, and animal feces, where out of 14 butterfly species identified, 11 dominant species sucked minerals on the banks of rivers or mud puddles, two species visited rotten fruit, and one species was seen in animal feces. Nectar feed has the characteristics of large and round-elongated pollen, which is more efficient for sticking to the insect's body. In contrast, the round-elongated oblate shape in Oxalis barrelieri shows strategic differences in the transfer of varying pollen norms, such as echinate and scabrate. The results of this study can be a reference for butterfly researchers to provide an overview of the diversity of nectar-producing plant feed along with its morphological characteristics and non-nectar feed utilized by butterflies on the Sampe Marta Cave tourist route

Effect of gradual pollen presentation on pollination efficiency and reproduction of Vaccinium corymbosum Berkeley in two habitats

IntroductionGradual pollen presentation is a reproductive strategy for plants to improve the efficiency and accuracy of pollen export and acceptance as well as to promote outcrossing. Vaccinium corymbosum Berkeley has a typical mechanism of gradual pollen presentation.MethodsIn this study, we used indoor and outdoor observations to investigate the floral characteristics, pollination characteristics and breeding system of this species in open ground and greenhouse.ResultsThe results showed that the single white, inverted bell-shaped flower of V. corymbosum was able to effectively avoid the negative effects of rainfall, nectar dilution and pollen removal by wind, and improved pollen viability and the duration of stigma receptivity. The setting rate of ‘Northland’ is higher than open ground by artificial pollination in greenhouse, therefore, greenhouses are more suitable for ‘Northland’ reproduction. The gradual pollen presentation prolongs dispersal time, promotes pollinator participation in the pollination process, increases staminate fitness, and provides for nectar feeding by pollinators as well as pollen export. Bombus spp. and A. m. ligustica were effective pollinators in the open ground and greenhouse, and the pollination efficiency of Bombus spp. was higher than that of A. m. ligustica, and greenhouse pollination is more efficient than open ground. The coincidence of the peak period of pollinator visits with the period of highest pollen viability and optimal pollination of stigmas, as well as the high nectar production, could maximize the frequency of pollinator visits and increase the chances of successful pollination as well as the pollination efficiency.DiscussionTherefore, it is important to study the floral characteristics of V. corymbosum Berkeley and the mechanism of gradual pollen presentation in order to improve the pollination efficiency and promote the success of outcrossing, which can provide a theoretical basis for the breeding of V. corymbosum.

Reinstatement of Acalypha fallax Mull. Arg. and description of A. brittoi sp. nov. based on micromorphological and molecular characters

In 1865, Müller Argoviensis proposed Acalypha fallax based on specimens from Peninsula Indiae orientalis, which is now considered synonymous with A. lanceolata Willd. A recent study conducted in Tamil Nadu, India, from 2019 to 2022 thoroughly examined Acalypha species using multiple criteria: leaf epidermal characteristics, seed morphology, pollen features observed via scanning electron microscopy (SEM), and sequencing of the ITS, rbcL and matK spacer regions. This work identified distinctions between A. fallax and A. lanceolata, such as longer peduncles, obovate bracts in male flowers, and stems with two types of trichomes: strigose and hirsute. Moreover, the study proposed a new species, A. brittoi, which is described here as distinguishable from A. fallax by its larger leaf blades with 13–14‐toothed margins (compared to smaller blades with 8–9‐toothed margins in A. fallax), and by the ovate perianth of its male flowers (versus orbicular perianth in A. fallax). Unique patterns of leaf epidermal crystals and granules on seed surfaces further aided in distinguishing A. fallax from A. brittoi. Molecular analysis additionally confirmed genetic differences among these three species.

Amaranthaceae Pollen Trends in the Air

Understanding the trends of airborne pollen allergens is of great importance given the high prevalence and socioeconomic impact of pollen-related allergic diseases globally. To study the morphological features of Amaranthaceae pollen, assess its contribution to the aerobiological situation in the city of Karakol and identify periods of increased concentration in order to improve the diagnosis and prevention of pollinosis symptoms in patients. Aerobiological sampling using a Lanzoni pollen trap was carried out from April to October over a three-year period (2015–2017) in Karakol city. Pollen identification and differential counting were performed according to current standard methodology and specially developed guides and atlases. Pollen characteristics of 4 Amaranthaceae species were visualized using scanning electron microscopy (Hitachi) to provide a detailed understanding of the surface structure and ornamentation of pollen grains. The decadal curve of Amaranthaceae pollen concentration in Karakol is unimodal, with often overlapping quantitative characteristics: 6615 (2nd decade of August 2015), 1326 (1st decade of 2016), 444 pollen grains / m3 (1st decade of 2017). At the same time, strong interannual variability of atmospheric pollen levels was observed, depending both on the pollen production of the plants themselves and on meteorological parameters, especially temperature and precipitation, changes in the traditional farming system. The response of summer-flowering Amaranthaceae weeds to climate change was demonstrated, which consists in a decrease in the annual pollen index, which corresponds to the global trend. Peak concentrations of Amaranthaceae pollen many times exceeded clinical threshold values in the air. On the surface of the Bassia scopariapollen exine, the ultrastructure study revealed the smallest (1.5-2.0 μm) granules of sporopollenin or orbicules (Ubisch bodies), which play a role in the spread of allergens. The obtained data are important in terms of increasing public awareness of the dominant pollen of the Amaranthaceae family, optimizing diagnostics, treatment and prevention of pollinosis.

Investigation of pollen morphology and viability of sweet and sour cherry genotypes by multivariate analysis.

The aim of this study was to examine the dimensions and surface morphology of pollen grains of some sweet and sour cherry genotypes through scanning electron microscopy (SEM) as an additional alternative identification tool. In vitro pollen germination and pollen tube length as indicators of their viability were determined as well. Observations were carried on 10 sweet cherry (Prunus avium L.) and 7 sour cherry (Prunus cerasus L.) genotypes. All genotypes had prolate, tricolpate pollen grains, and striate exine ornamentation, with more parallel longitudinal ridges. Significant differences among genotypes within species and between species were found for most pollen grain characteristics and exine ornamentation. In both sweet and sour cherry the largest variability was recorded for colpus length (CV = 15.0% and 12.9%, respectively). For sweet cherry genotypes, in vitro pollen germination and pollen tube length ranged between 1.4% to 51.5% and 360.4 to 669.3 μm respectively, while for sour cherries they ranged from 15.5% to 37.0% and 96.3 to 960.2 μm, respectively. The results of the correlation analysis showed that in vitro pollen germination correlated positively with pollen length/pollen width (L/W) ratio (r = .640) and furrow width (r = .588), and negatively with the number of ridges (r = -.517), while pollen tube length was not significantly correlated with any of the studied characteristics. Principal component analysis (PCA) revealed that pollen length, pollen width, L/W ratio, colpus length, mesocolpium width, and ridge width are relevant tools to discriminate among the studied genotypes. The measurements made on pollen grains did not reveal individually big differences, but when all features were considered together, the pollen of each genotype exhibited a unique pattern. The distribution on the scatter plot showed considerable variation among sweet and sour cherry genotypes based on pollen morphological characteristics, which led to their distribution into two separate groups. This demonstrates the ability to distinguish cherry species based on pollen morphological characteristics determined by SEM. To improve discriminative ability for genotypes within species combination between pollen ultrastructural analysis, morphological and molecular markers is desirable, in subsequent work. RESEARCH HIGHLIGHTS: Significant differences in pollen characteristics between sweet and sour cherry. Significance of pollen morphology in taxonomic differentiation. Significance of SEM studies for the taxonomic identification.

Pollen Characteristics of Diploid and Tetraploid Grape Cultivars

For a successful grapevine breeding program, pollen viability, germination ability, and cultivar compatibility information are of vital importance. In this study, pollen viability, germination rates, pollen tube lengths, and pollen tube diameters of three grape cultivars [Kyoho (4n), Ekşi Kara (2n), and Gök Üzüm (2n)] were investigated. Pollen viability rates were determined using the IKI (iodine potassium iodide) staining test. In vitro, pollen germination rates were determined using a semi-solid medium containing 20% ​​sucrose and 1% agar. As a result, significant differences were detected in pollen viability, germination rates, and pollen tube lengths of the examined grape cultivars. The first germination started at the 48th hour in all three grape cultivars. In cv. Ekşi Kara had the highest pollen viability while the lowest (3.05%) value in terms of pollen germination was determined. Pollen tube length and pollen tube diameter of the cv. Kyoho had higher values ​​than the other two diploid cultivars. Pollen tube formation started in the first 48th hours, while pollen tube growth continued to increase until the 96th hours. As a result, it was confirmed that the flower structure of the cv. Ekşi Kara was functionally female. In suitable ecologies, diploid cv. Gök Üzüm and tetraploid cv. Kyoho were found to be usable as pollinators.

Palynological investigation of some genera of Cichorieae (Asteraceae) in Iran.

The pollen morphology of 33 species belonging to the genera Lactuca, Launaea, Cicerbita, Sonchus, Condrilla (tribe Cichorieae: Asteraceae) from Iran were studied with light and electron microscopies. The pollen grains of the investigated taxa are almost oblate-spherical to prolate-spherical, the shapes are circular in equatorial view, hexagonal in polar view, only Sonchus species are triangular or quadrangular in polar view, isopolar, symmetrical and trizonocolporate, except Sonchus and Chondrilla species, which have tri- to tetrazonocolporate pollen grains, and echinolophate. The size and number of spines in the polar area and the number of spines in the paraporal ridges and equatorial ridges proved to be the most taxonomically authentic characteristics in this study. Three pollen types were distinguished, as in alignment with previous studies. Cluster analysis by Ward method based on 10 quantitative morphological characteristics of pollen grains revealed that the species could be grouped based on the pollen characteristics. Moreover, three species of Cicerbita including Cicerbita scoparia (Rech. f. & Köie) Kitam, C. rechingeriana (Tuisl) Coșkunç., M. Güzel & N. Kilian and C. microcephala (DC.) M. Güzel, Coșkunç. & N. Kilian were recorded for the first time in Iran. Although the characteristics of the pollen grains were useful for distinguishing the species in sub-tribes, in some cases, this did not confirm recent phylogenetic results. The pollen characteristics described in this study provide data that may be useful for future systematic studies aiming to complete the knowledge on Cichorieae species. RESEARCH HIGHLIGHTS: In the present study, the pollen morphology of 33 species belonging to five genera of the Cichorieae are investigated with scanning electron microscopy and 12 species are analyzed for the first time. The cluster analysis based on the quantitative morphological characteristics of pollen grains revealed that the species could be grouped based on the pollen characteristics. In addition, three species of Cicerbita are reported for the first time in Iran.

Integrated analysis of remote sensing with meteorological and health data for allergic rhinitis forecasting in Tianjin.

Long time series of vegetation monitoring can be carried out by remote sensing data, the level of urban greening is objectively described, and the spatial characteristics of plant pollen are indirectly understood. Pollen is the main allergen in patients with seasonal allergic rhinitis. Meteorological factors affect the release and diffusion of pollen. Therefore, studying of the complex relationship between meteorological factors and allergic rhinitis is essential for effective prevention and treatment of the disease. In this study, we leverage remote sensing data for a comprehensive decade-long analysis of urban greening in Tianjin, which exhibits an annual increase in vegetative cover of 0.51 per annum, focusing on its impact on allergic rhinitis through changes in pollen distribution. Utilizing high-resolution imagery, we quantify changes in urban Fractional Vegetation Coverage (FVC) and its correlation with pollen types and allergic rhinitis cases. Our analysis reveals a significant correlation between FVC trends and pollen concentrations, with a surprising value of 0.71, highlighting the influence of urban greenery on allergenic pollen levels. We establish a robust connection between the seasonal patterns of pollen outbreaks and allergic rhinitis consultations, with a noticeable increase in consultations during high pollen seasons. our findings indicate a higher allergenic potential of herbaceous compared to woody vegetation. This nuanced understanding underscores the importance of pollen sensitivity, alongside concentration, in driving allergic rhinitis incidents. Utilizing a Generalized Linear Model, significant features influencing the number of visits for allergic rhinitis (P < 0.05) were identified. Both GLM and LSTM models were employed to forecast the visitation volumes for rhinitis during the spring and summer-autumn of 2022. Upon validation, it was found that the R² values between the simulated and actual values for both GLM and LSTM models surpassed the 95% confidence threshold. Moreover, the R² values for the summer-autumn seasons (GLM: 0.56, LSTM: 0.72) were higher than those for spring (GLM: 0.22, LSTM: 0.47). Comparing the errors between the simulated and actual values of GLM and LSTM models, LSTM exhibited higher simulation precision in both spring and summer-autumn seasons, demonstrating superior simulation performance. Overall, our study pioneers the integration of remote sensing with meteorological and health data for allergic rhinitis forecasting. This integrative approach provides valuable insights for public health planning, particularly in urban settings, and lays the groundwork for advanced, location-specific allergenic pollen forecasting and mitigation strategies.

New pollen taxon Syncolpraedapollis angolensis nov. gen. sp. nov.: A noteworthy discovery reported in the preliminary investigation of the latest Eocene-latest Oligocene deposits in the Kwanza Basin, Angola

A palynostratigraphic study of the upper Cunga and lower Quifangondo deposits in the Cabo de São Brás section, Kwanza Basin, Angola, has revealed a new pollen named Syncolpraedapollis angolensis nov. gen. sp. nov. This finding was part of a wider survey in the upper Cunga and lower Quifangondo deposits of the Cabo de São Brás section, Kwanza Basin, Angola, covering the latest Eocene to the latest Oligocene.The novel pollen features unique characteristics, notably a 3-syncolporate structure with well-defined and distinctive pores. The pollen grain is adorned with a free but irregular reticulum with an irregular polygonal mesh. Syncolpraedapollis angolensis nov. gen. sp. nov. is sporadically but consistently observed within the latest Eocene-latest Oligocene interval, conspicuously absent in the underlying Eocene sediments (lower Cunga Formation) and occurring infrequently in the latest Oligocene sediments (lower Quifangondo Formation). Thus, it is plausible to infer a limited age range, likely restricted to the latest Eocene-latest Oligocene, as previous studies in the Kwanza Basin have not documented this pollen.

STUDIES ON THE POLLEN MORPHOLOGY OF SOME WEEDY FLORA OF NIZAMABAD DISTRICT OF TELANGANA STATE, INDIA

The present work is aimed to study the pollen morphology of weed plants by light microscopy (LM). Polleniferous material of eight weed plants viz., Mimosa pudica, Cleome viscosa, Tribulus terrestris, Lantana camara, Commelina benghalensis, Ziziphus mauritiana, Cardiospermum halicacabum and Datura stramonium were collected from in and around agricultural lands of Nizamabad district, Telangana, India during 2022-2023.The pollen features viz., shape, apertures and the sporoderm pattern was studied. The pollen grains studied showed spheroidal, sub- prolate, eu-oblate, oblate-spheroidal, oblate to per oblate shape. The apertural diversity include tricolporate, triporate, pantoporate and monosulcate condition. The Exine ornamentation is indicated by psilate in three species, striate in two, reticulate in another two species and one species possess microechinate pattern. The diversity in pollen features are helpful in the identification of the taxa at various levels. This study highlights the some of the common weed pollen morphological features useful to distinguish the species of weeds.

Exploring the Floral Biology of Salix alba: Insights into Reproductive Dynamics, Pollen Production and Pollen Morphology in Kashmir Himalayas

This study investigates the floral phenology, pollen production and pollen characteristics of Salix alba (white willow) over the years 2022 and 2023, highlighting inter-annual and individual tree variations. In 2022, male catkins began flowering between March 8 and March 10, while female catkins initiated between March 14 and March 22. Flowering for male catkins lasted until mid-May and for female catkins until late May. In 2023, male catkins started flowering from March 10 to March 14 and female catkins from March 17 to March 24, with similar flowering durations. Inflorescence diameters varied among individual trees, ranging from 4.4 mm to 7.7 mm for male catkins and 6.1 mm to 8.1 mm for female catkins across the two years. Pollen production exhibited significant variability with the highest recorded at 4,600,995,000 grains per tree and the lowest at 498,312,500 grains per tree. On average, trees produced approximately 2,164,836,667 pollen grains. Pollen viability ranged from 75% to 80%, with sizes between 16 µm and 26 µm. The pollen-ovule ratio also showed substantial differences, with the highest ratio observed at 7600:2 and the lowest at 2345:7. These findings underscore the considerable year-to-year and tree-to-tree variation in the reproductive traits of Salix alba, which may have implications for its breeding and conservation strategies.

Forecasting daily total pollen concentrations on a global scale.

There is evidence that global anthropogenic climate change may be impacting floral phenology and the temporal and spatial characteristics of aero-allergenic pollen. Given the extent of current and future climate uncertainty, there is a need to strengthen predictive pollen forecasts. The study aims to use CatBoost (CB) and deep learning (DL) models for predicting the daily total pollen concentration up to 14 days in advance for 23 cities, covering all five continents. The model includes the projected environmental parameters, recent concentrations (1, 2 and 4 weeks), and the past environmental explanatory variables, and their future values. The best pollen forecasts include Mexico City (R2(DL_7) ≈ .7), and Santiago (R2(DL_7) ≈ .8) for the 7th forecast day, respectively; while the weakest pollen forecasts are made for Brisbane (R2(DL_7) ≈ .4) and Seoul (R2(DL_7) ≈ .1) for the 7th forecast day. The global order of the five most important environmental variables in determining the daily total pollen concentrations is, in decreasing order: the past daily total pollen concentration, future 2 m temperature, past 2 m temperature, past soil temperature in 28-100 cm depth, and past soil temperature in 0-7 cm depth. City-related clusters of the most similar distribution of feature importance values of the environmental variables only slightly change on consecutive forecast days for Caxias do Sul, Cape Town, Brisbane, and Mexico City, while they often change for Sydney, Santiago, and Busan. This new knowledge of the ecological relationships of the most remarkable variables importance for pollen forecast models according to clusters, cities and forecast days is important for developing and improving the accuracy of airborne pollen forecasts.

A dataset of scanning electron microscope images of pollen from 15 species of Salsola L. in Xinjiang

In this study, we collected fifteen species of Salsola L. from Northern Xinjiang at the end of the flowering period in 2007, including Salsola. subcrassa, S. orientalis, and S. lanata, etc.. We first identified and classified these species by comparison of flowers and fruits, and then photographed the pollen from multiple angles, and analyzed them a using a LEO-1430VP scanning electron microscope with a maximum magnification of 20,000× and an image resolution of 1023×766 pixels. A total of 84 images were included in the study. The Salsola L. in the dataset was identified twice by an expert in Chenopodiaceae taxonomy, and a specialized staff operated a scanning electron microscope to observe pollen traits. Readers can access the corresponding pollen scanning electron microscope images in this dataset by referecing the species name of Salsola L.. The release of this dataset facilitates the in-depth study of the typical pollen characteristics of Salsola L. in Xinjiang and even in Central Asia. Moreover, it further complements and perfects the grouping system based on the morphological characteristics of Salsola L., and provides an important reference for the research on palynology, taxonomy, ecology and so on.

PALYNOLOGICAL CHARACTERIZATION OF HERBACEOUS AND WOODY FLORA OF LAHORE UNIVERSITY OF MANAGEMENT SCIENCES, LAHORE, PAKISTAN

The present study reveals palynomorphic characterization of woody and herbaceous flora of Lahore University of Management Sciences, Lahore. In this respect, 67 plant species including 56 dicots, 10 monocots and 1 gymnosperm belonging to 40 different families have been studied by using light microscopy. The present study demonstrates that the pollen morphology of herbaceous and woody flora of LUMS exhibits a huge diversity. The pollen features studied includes structure, volume, aperture, polar length, equatorial diameter, P/E ratio, shape, size, aperture and tectum. Pollen shape was mostly prolate spheroidal but oblate spheroidal, prolate, sub prolate, spheroidal and tricolpate were also observed in some species. Pollen aperture varied from porate to colpate and some species were inaperturate. Pollen tectum has been found reticulate in most species, while psilate, scabrate, verrucate, echinate and striate were also observed. Furthermore, the family name and common name have also been studied. Maximum pollen size is 176.92 µm found in Pinus caraniensis (pinaceae) and minimum pollen size is 88.87µm observed in Morus alba (Moraceae). This work is anticipated to be advantageous in documentation for taxonomic recognition of the plants of Lahore University of Management Sciences, Lahore (LUMS).

The Micromorphology and Its Taxonomic Value of the Genus Sanicula L. in China (Apiaceae).

The genus Sanicula L. possesses many medically important plants, belonging to the family Apiaceae. It is one of the most taxonomically difficult taxa, largely due to the great variability in habit, foliage, flowers and fruits. Previous studies have mainly focused on the molecular studies of this genus, and the morphological research for this genus was limited, especially in the micromorphological research. In the current study, we newly obtained leaf materials from twenty-two Sanicula members, fruit and pollen materials from twenty Sanicula members and performed comprehensively micromorphological analyses for this complicated genus. The results of the leaf epidermis showed that the upper and lower epidermis were smooth and glabrous, and the cell shape was polygonal or irregular. The patterns of anticlinal wall were shallowly undulating, deeply undulating, subflat or flat. The cuticular membrane ornamentations were diverse, and some species had epidermal appendage. All Sanicula species observed the stomata in the lower epidermis, and only five species (S. rugulosa, S. elongata, S. hacquetioides, S. tienmuensis and S. elata) observed stomata in the upper epidermis, which can easily identify them from other Sanicula members. In addition, we found that the fruits scarcely compressed, and some fruits had their distinctive shape, such as the fruit shape of S. tienmuensis was subglobose, S. subgiraldii was broadly ovate and S. pengshuiensis was ellipsoid. All Sanicula taxa fruits surfaces were covered with prickles, bristles, protuberance, or tubercles, prickles were either long or short, uncinate or straight, rarely scale-like, ribs inconspicuous or slightly prominent, but the prickles/bristles/tubercles were different in shape, sparseness and arrangement. The vittae were distinct in S. rubriflora, S. chinensis, S. caerulescens, S. pengshuiensis, S. pauciflora, S. lamelligera, S. oviformis, S. flavovirens and S. elata, and the remaining taxa were obscure. These findings indicated that the fruits can clearly distinguish these Sanicula members. Furthermore, the micromorphological characteristics of pollen showed that the equatorial view included four shapes: ellipsoid, subrectangular, equatorially constricted and super-rectangular-equatorially constricted; and the polar view possessed four shapes: triangular, triangular-circular, suborbicular and trilobate circular. The germ furrow and the outer wall ornamentation of all Sanicula taxa were quite similar, indicating that the genus was a natural unit. In summary, our study promoted the improvement of a taxonomic system for the genus and also provided additional evidence for future taxonomic study of the genus Sanicula.

Analysis of Thermal Characteristics of Potato and Hop Pollen for Their Cryopreservation and Cross-Breeding.

This study investigated the thermal properties of potato and hop pollen for cryopreservation and subsequent cross-breeding. Phase transitions and frozen water content in selected pollen samples were measured using a differential scanning calorimeter (DSC). Unlike hop pollen, potato pollen showed high variability in thermal properties and water content. Three specific types of pollen samples based on their thermal characteristics and water content were distinguished by DSC in potato: (1) 'glassy', with a water content lower than 0.21 g water per g dry matter; (2) 'transient', with a water content between 0.27 and 0.34 g of water per g of dry matter; (3) 'frozen', with a water content higher than 0.34 g of water per g of dry matter. Only the 'glassy' pollen samples with a low water content showed suitable properties for its long-term storage using cryopreservation in potato and hops. Cryopreservation of pollen did not significantly reduce its viability, and cryopreserved pollen was successfully used to produce both potato and hop hybrids. The results indicate that cryopreservation is a feasible technique for the preservation and utilization of pollen of these crops in the breeding process.

Local spatiotemporal dynamics of particulate matter and oak pollen measured by machine learning aided optical particle counters

Conventional techniques for monitoring pollen currently have significant limitations in terms of labour, cost and the spatiotemporal resolution that can be achieved. Pollen monitoring networks across the world are generally sparse and are not able to fully represent the detailed characteristics of airborne pollen. There are few studies that observe concentrations on a local scale, and even fewer that do so in ecologically rich rural areas and close to emitting sources. Better understanding of these would be relevant to occupational risk assessments for public health, as well as ecology, biodiversity, and climate.We present a study using low-cost optical particle counters (OPCs) and the application of machine learning models to monitor particulate matter and pollen within a mature oak forest in the UK. We characterise the observed oak pollen concentrations, first during an OPC colocation period (6 days) for calibration purposes, then for a period (36 days) when the OPCs were distributed on an observational tower at different heights through the canopy. We assess the efficacy and usefulness of this method and discuss directions for future development, including the requirements for training data.The results show promise, with the derived pollen concentrations following the expected diurnal trends and interactions with meteorological variables. Quercus pollen concentrations appeared greatest when measured at the canopy height of the forest (20–30 m). Quercus pollen concentrations were lowest at the greatest measurement height that is above the canopy (40 m), which is congruent with previous studies of background pollen in urban environments. The attenuation of pollen concentrations as sources are depleted is also observed across the season and at different heights, with some evidence that the pollen concentrations persist later at the lowest level beneath the canopy (10 m) where catkins mature latest in the season compared to higher catkins.

A Study of the Pollen Grains of Indian Clematis Linn. (Ranunculaceae)

A illustrated account of the pollen grains of 32 species of genus Clematis (Dill, ex) Linn., mostly Indian, has been presented and their systematic significance evaluated. The pollen is usually 3-zono-colpate, but some have 4-zono-colpate pollen as well. In C. cadmia Buch.- Ham. Ex Hk.f. &amp; Thom., the pollen is panporate. The pollen features in Clematis exhibit a predominantly negatively reticulate sexine pattern and are of little phylogenetic significance.