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.

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.

Fossil pollen from early Palaeogene sediments in western India provides phylogenetic insights into divergence history and pollen character evolution in the pantropical family Ebenaceae

Many plant families lack substantive fossil records, limiting our understanding of their origin and evolution. The abundance and preservation potential of pollen through geological time have helped to overcome such limitations and have provided reliable fossils for reconstructing biogeographical history and character evolution in many angiosperm families. Here, using scanning electron microscopy, we identified six Ebenaceae-type fossil pollen grains from early Palaeogene sediments of western India. Phenetic and phylogenetic analyses using pollen characters of fossil and extant taxa reavealed affinities of these fossils to three genera of Ebenaceae (Euclea, Royena and Diospyros). Furthermore, our divergence dating analysis using these fossils as priors suggested a Gondwanan origin for the family during the mid-Cretaceous [c. 107 Mya, 95% highest posterior density (HPD): 100–112 Mya] and supports the boreotropical and ‘out of India’ dispersal hypotheses as the most probable explanations for the present global distribution of the family. The study also supports the dispersal of the family into India, from Africa, through the Kohistan–Ladakh Arc during the Palaeocene. Finally, comparative phylogenetic analyses suggest significant synapomorphic and phylogenetic signals for a few selected pollen characters in Ebenaceae. Our findings have important implications for understanding the biogeography and evolution of the highly diverse and ecologically and economically important family Ebenaceae.

Evolution of Angiosperm Pollen: 8. Lamiids

Lamiids, a clade composed of approximately 15% of all flowering plants, contains more than 50,000 species dispersed across 49 families and eight orders (APG IV, 2016). This paper is the eighth in a series that analyzes pollen characters across angiosperms. We reconstructed a maximum likelihood tree based on the most recent phylogenetic studies for the Lamiids, comprising 150 terminal genera (including six outgroups) and covering all eight orders and 49 families within the clade. To illustrate pollen diversity across the Lamiids, pollen grains from 22 species (22 genera in 14 families) were imaged under light, scanning, and transmission electron microscopy. Eighteen pollen characters that were documented from previous publications, websites, and our new observations were coded and optimized onto the reconstructed phylogenetic tree using Fitch parsimony, maximum likelihood, and hierarchical Bayesian analysis. Pollen morphology of the Lamiids is highly diverse, particularly in shape class, pollen size, aperture number, endoaperture shape, supratectal element shape, and tectum sculpture. In addition, some genera show relatively high infrageneric pollen variation within the Lamiids: i.e., Coffea L., Jacquemontia Choisy, Justicia L., Pedicularis L., Psychotria L. nom. cons., Sesamum L., Stachytarpheta Vahl, and Veronica L. The plesiomorphic states for 16 pollen characters were inferred unambiguously, and 10 of them displayed consistent plesiomorphic states under all optimization methods. Seventy-one lineages at or above the family level are characterized by pollen character state transitions. We identified diagnostic character states for monophyletic clades and explored palynological evidence to shed light on unresolved relationships. For example, palynological evidence supports the monophyly of Garryales and Metteniusaceae, and sister relationships between Icacinaceae and Oncothecaceae, as well as between Vahliales and Solanales. The evolutionary patterns of pollen morphology found in this study reconfirm several previously postulated evolutionary trends, which include an increase in aperture number, a transition from equatorially arranged apertures to globally distributed ones, and an increase in exine ornamentation complexity. Furthermore, there is a significant correlation between pollen characters and a number of ecological factors, e.g., pollen size and pollination type, pollen ornamentation and pollination type, and shape class and plant growth form. Our results provide insight into the ecological, environmental, and evolutionary mechanisms driving pollen character state changes in the Lamiids.

Integrative Taxonomic Analyses Sheds Light on Three Historically Disputed American Spermacoce Species, and a Key to the American Species of Spermacoce (Spermacoceae, Rubiaceae)

Abstract—There has been great confusion between Spermacoce glabra, S. riparia, and S. tenuior since their original descriptions. These species can be distinguished mostly by their seed features. Clustering and principal coordinate analyses (PCoA) were used to scrutinize the formation of hierarchical non-overlapping groups strictly according to the degree of morphological similarity. Thirteen characters were scored for 26 herbaria specimens. The taxonomic identity of these three species is discussed. Redefined descriptions and illustrations are provided, especially for fruit, seed, and pollen characters. A map and a discussion of the updated geographical distribution of these species are included. A table summarizing the different taxonomic concepts in contemporary floristic studies and an identification key to all American Spermacoce species are also provided. The new combination Spermacoce affinis (DC.) R.M. Salas is presented here.

Comparative assessment of pollen micromorphology of Salvia assurgens (Lamiaceae), an endemic sage from Mexico

The present study provides novel information about the pollen of Salvia assurgens. Pollen grains were collected and described based on their observed characters by light microscope and scanning electron microscopy. The species is distinguished from other Mexican salvias by having small pollen grains (14.2 × 18.2 µm), thin primary muri (0.2 µm thick), elongated primary lumina (1.03 µm long) and secondary lumina with relatively few perforations (9, range 5–14). Pollen characters are similar to those of the majority of American salvias. Regarding Mexican sages, there has been little palynological research, and only 23 species of 32 examined have been quantitatively studied. Standardization is needed in different aspects of palynological studies, especially in relation to measurement protocols and data analysis, as well as the increased use of scanning electron microscopy (SEM), since the majority of differences among species are provided by SEM microscope observation.

Identification of Pollen Characteristics as Apis cerana Feed Sources in Honeycomb, in Serang Purbalingga

Serang Purbalingga village is a fertile area and has the potential for the development of Apis cerana honeybee business. Honeybee products are known to have high economic value. The development of honeybee business will be better if supported by the avaibility of pollen from flowering plants as feed sources. Pollen that use to be A. cerana feed sources are taken from plants flower around the beehive and matched with pollen inside honeycomb. The purpose of this research is to determine the diversity and character of pollen from plants found around beehive and inside A. cerana honeycomb. This research conducted by descriptive survey method where the data obtained from field used as material for analysis and describing the characteristics of pollen found. Variable in this research is pollen characters with parameters are pollen units, size, shape, apertures and ornamentation. Based on results, there are 23 species of plants included in 17 families found around the beehive with varying of pollen shape, namely spheroidal, prolate-spheroidal, sub-prolate, and prolate. The smallest to largest pollen sizes are minutae, mediae, and magnae. Types of pollen ornamentations are rugulate, reticulate, echinate, psilate, scabrate, to baculate. Pollen apertures are varies monosulcate, monoporate, tricolporate, tricolpate, tetracolpate, hexacolpate to syncolpate. Pollen characters inside honeycomb are identical to 12 pollen of plant species found around the beehive where the pollen shape are spheroidal, prolate-spheroidal, sub-prolate and prolate. There are several types of ornamentation, namely reticulate, rugulate, echinate, psilate and sacbratte. Apertures are varies from monosulcate, monoporate, tricolporate, tricolpate to syncolpate. Key words : Apis cerana, characters,diversity, pollen, Purbalingga

Morphology, anatomy, palynology and achene micromorphology of Bellis L. (Asteraceae) species from Turkey

In the present study, the morphological characters, root, stem and leaf anatomy, pollen and achene micromorphology of Bellis L. species (Bellis annua L., B. perennis L. and B. sylvestris Cirillo) distributed in Turkey have been investigated on light and scanning electron microscope. Palynological analysis showed that pollen characters were found as small to medium size, isopolar, radially symmetrical, oblate spheroidal and prolate spheroidal, tricolporate and echinate-perforate ornamentation in the three species. Achene characters were found dark brown to yellow in colour, often cylindrical, compressed, with thickened margin, obovate orobovoid shaped, pappus absent and the coat ornamentations are rectangular with short hairs on the surface. As a result of this study, leaf morphology and some pollen characteristics such as pollen size, shape, perforation and distance between spines were demonstrated to be different among the Bellis species.

Contribution to the knowledge of the pollen morphology of the genus Salvia (Lamiaceae)

The pollen grains of 19 Turkish Salvia species in Aethiopis, Drymosphace, Hemisphace, Hymenosphace and Salvia sections, 13 of which are endemic to Turkey, were investigated, documented and illustrated through Light Microscopy (LM) and Scanning Electron Microscopy (SEM). This study provides pollen data of 14 species for the first time. The pollen grains of the species examined are monads, isopolar, radially symmetrical and hexacolpate, mostly medium in size, slightly elliptic to more or less circular in polar view and mainly oblate-spheroidal in equatorial view. Two different ornamentation types are recognized on exine sculpturing; reticulate-perforate and bireticulate. The present results do not generally support the traditional infrageneric classification of Salvia, but provide useful pollen characters for species delimitation.

Cytogenetic and pollen identification of genus Gagnepainia (Zingiberaceae) in Thailand

Gagnepainia godefroyi K. Schumann, 1904 and G. harmandii K. Schumann, 1904 belong to the genus Gagnepainia K. Schumann, 1904 of the Ginger family. They have the potential to be developed as medicinal and attractive ornamental plants. To date, the knowledge on the cytological and reproductive aspects of Gagnepainia have not been publicly available. Therefore, the aims of this research are to investigate the cytogenetic and pollen characters of Gagnepainia species using light, fluorescence, and scanning electron microscopes. The regular meiotic figures of 15 bivalents are found in both species and presented for the first time. These evidences indicate that Gagnepainia is diploid and contains 2n = 2x = 30 with basic number of x = 15. The mean nuclear DNA contents range from 1.986 pg in Gagnepainia sp., 2.090 pg in G. godefroyi to 2.195 pg in G. harmandii. Pollens of all species are monad, inaperturate, prolate with bilateral symmetry, and thick wall with fossulate exine sculpturing. The pollen size of G. harmandii (74.506 ± 5.075 μm, 56.082 ± 6.459 μm) is significantly larger than that of G. godefroyi (59.968 ± 3.484 μm, 45.439 ± 2.870 μm). Both 2C DNA content and pollen size are the effective characteristics for species discrimination. The reproductive evidence of high meiotic stability and normal pollen production indicate that both Gagnepainia species have high fertility and seed productivity, which are in accordance with the broad distribution. The present study provides good cytogenetic and pollen characters not only for plant identification, but also plant fertility assessment through plant genetic resource management and improvement of Gagnepainia.