A Comprehensive Study of the Genus Sanguisorba (Rosaceae) Based on the Floral Micromorphology, Palynology, and Plastome Analysis

Sanguisorba, commonly known as burnet, is a genus in the family Rosaceae native to the temperate regions of the Northern hemisphere. Five of its thirty species are distributed in Korea: Sanguisorba officinalis, S. stipulata, S. hakusanensis, S. longifolia, and S. tenuifolia. S. officinalis has been designated as a medicinal remedy in the Chinese and Korean Herbal Pharmacopeias. Despite being a valuable medicinal resource, the morphological and genomic information, as well as the genetic characteristics of Sanguisorba, are still elusive. Therefore, we carried out the first comprehensive study on the floral micromorphology, palynology, and complete chloroplast (cp) genome of the Sanguisorba species. The outer sepal waxes and hypanthium characters showed diagnostic value, despite a similar floral micromorphology across different species. All the studied Sanguisorba pollen were small to medium, oblate to prolate-spheroidal, and their exine ornamentation was microechinate. The orbicules, which are possibly synapomorphic, were consistently absent in this genus. Additionally, the cp genomes of S. officinalis, S. stipulata, and S. hakusanensis have been completely sequenced. The comparative analysis of the reported Sanguisorba cp genomes revealed local divergence regions. The nucleotide diversity of trnH-psbA and rps2-rpoC2, referred to as hotspot regions, revealed the highest pi values in six Sanguisorba. The ndhG indicated positive selection pressures as a species-specific variation in S. filiformis. The S. stipulata and S. tenuifolia species had psbK genes at the selected pressures. We developed new DNA barcodes that distinguish the typical S. officinalis and S. officinalis var. longifolia, important herbal medicinal plants, from other similar Sanguisorba species with species-specific distinctive markers. The phylogenetic trees showed the positions of the reported Sanguisorba species; S. officinalis, S. tenuifolia, and S. stipulata showed the nearest genetic distance. The results of our comprehensive study on micromorphology, pollen chemistry, cp genome analysis, and the development of species identification markers can provide valuable information for future studies on S. officinalis, including those highlighting it as an important medicinal resource.

Gamma rays induced morphological, flowering and palynological modifications in horse gram (Macrotyloma uniflorum)

Aim: The quest was framed to analyse the effect of high dose of gamma rays on morphological, flowering, and palynological traits in horse gram (Macrotyloma uniflorum). Methodology: Two horse gram varieties PAIYUR 2 and CRIDA 1-18 R were mutated using 32 mutagenic combinations. Sterile plants produced by gamma rays: 400 Gy were utilized to study the alterations in morphological, flowering characters in 20 randomly selected plants, and palynological traits using scanning electron microscope. Results: Gamma rays (GR):400 Gy produced sterile plants with altered ideotype and reproductive traits. It reduced expression of yield attributing traits, delayed first flowering, modified anther, and pollen size. The palynological changes included genotype dependant variation in pili number, size and exine ornamentation. Interpretation: High gamma ray dose is lethal to horse gram which was evidenced through grave modifications in morphological and palynological traits. These alterations resulted in sterility. Sterile plants tried to repair the irradiation induced damages and hence failed to perform routine reproductive functions.

Taxonomic studies in the genus Haplanthodes (Acanthaceae)

The endemic Indian genus Haplanthodes (Acanthaceae) is revised. Four species, viz. H. neilgherryensis, H. plumosa, H. tentaculata and H. verticillata and a new variety, H. neilgherryensis var. toranganensis are recognized. Lectotype is designated for Haplanthodes, Haplanthus plumosus and H. verticillaris. The nomenclature of the Linnaean name Ruellia tentaculata is also discussed. Micromorphology of seed using light microscope (LM) and scanning electron microscope (SEM) is observed for the first time, and two types, reticulate and micro papillate, have been recognized based on surface sculpturing pattern. The genus differs from the related genera Andrographis and Haplanthus by distinctly two grooved seeds with hygroscopic hairs. Pollen grains of the genus are oblate or prolate spheroidal, distinctly triangular, trizonocolporate with reticulate exine ornamentation.

Pollen Morphology in Various Life-form of Aquatic Macrophytes

Ability of angiosperms to produce flowers and seeds for the sexual reproduction is important also in aquatic plants. Pollination in aquatic plants is facilitated by insects, wind, and water, however, pollen morphology related to the plant’s life forms and pollen dispersal are not well described. This study investigates pollen morphology of selected aquatic macrophytes. Plants were collected and preserved as dried specimens. Mature pollen grains of each species were separated from the anthers and then placed on glass slides and mounted with distilled water. Pollen shape and size were observed under a light microscope (LM). Number of apertures and exine ornamentation were examined using scanning electron microscope (SEM). Closely related plant species had similar pollen morphology. Among the 28 species studied, pollen size varied from small to very large (range 10–200 µm) and their shapes were prolate-spheroidal, prolate, oblate, suboblate, and oblate-spheroidal. Some species had inaperturate pollen grains; the remainders were monoaperture, triaperture or polyaperture. Both colpate and porate apertures were found. The pollen surfaces were echinate, fovelate, granulate, lophate, plicate, regulate, regulate-fovelate, reticulate, striate, and verrucate, respectively. Keywords: Aquatic plants, Palynology, Pollen ornamentation, Pollination, SEM

PALYNOLOGICAL INVESTIGATIONS ON SOME SELECTED BEE FORAGE PLANTS OF FAMILY FABACEAE USING LIGHT AND SCANNING ELECTRON MICROSCOPY FROM HIMACHAL PRADESH, INDIA

The study aimed to investigate and describe the pollen morphology of six nectariferous and polleniferous members of family fabaceae by using light and scanning electron microscope. Pollen grains of Albizia lebbeck, Bauhinia variegata, Caesalpinia decalpetala, Cassia fistula, Dalbergia sissoo and Robinia pseudoacacia were examined for the morphological characterization. The pollen grains were analysed in terms of aggregation, shape, shape class, size, aperture, polarity, symmetry, surface pattern and exine complexity. All the pollen had solitary grains, except Albizzia lebbeck having compound grains. The shape of pollen grains varies from circular-ovoid in Albizia lebbeck, triangular in Bauhinia variegata, oval in Caesalpinia decapetala, oval / round in Cassia fistula and triangular/round in Dalbergia sissoo and triangular/elongated oval Robinia pseudoacacia. The pollens were either prolate-spheroidal or oblate spheroidal. The size of pollen grains studied ranged from small, medium to large sized among different members of family fabaceae. Most of pollens observed were tricolporate, except pollens of Dalbergia sissoo which were tricolpate and triporate. Exine ornamentation include psilate/faveolate in Albizzia lebbeck, psilate in Dalbergia sissoo and Robinia pseudoacacia, straite –reticulate in Bauhinia variegata, reticulate-rugulate in Cassia fistula and Caesalpinia decapetala. All the pollens observed were isopolar and radially symmetrical. The purpose of this study is to increase knowledge of the aspects related to the variability and to characterize the pollen morphology of some members of family fabaceae and to evaluate the utility of pollen features in order to develop an additional alternative plant material identification tool. Moreover, such studies can be of utmost important to students, researchers, and beekeeping industry, horticulture and forest departments.

Pollen morphology and variability of species from the genus Rubus L. (Rosaceae) alien and invasive in Poland

Rubus L. is one of the most species-rich and most taxonomically challenging genera in the family Rosaceae. The aim of this study was to investigate pollen morphology and the ranges of inter- and intraspecific variability of the studied Rubus alien species, as well as verify the taxonomic usefulness of these traits in distinguishing studied taxa from this genus. We analysed six quantitative pollen characteristics and the following qualitative ones: exine ornamentation, pollen outline and shape. The study was conducted on 24 samples of six alien Rubus species found in Poland. 720 pollen grains were measured in total. The most important pollen features included exine ornamentation and length of the polar axis (P). In the conducted studies there were no features of pollen indicating “invasiveness”. The results of our research fill the gap in knowledge on pollen structure in Rubus species alien to Poland and Europe. They may constitute a foundation for further research on the reproduction of these species (e.g. pollen viability and fertility), thus facilitating identification of features determining their expansive character.

Pollen morphology and variability of Polish native species from genus Salix L.

The pollen morphology was studied of 24 Salix species native to Poland, which represented two subgenera, 17 sections and five subsections occurring in Poland. The aim of this study was to discover the taxonomical usefulness of the pollen features under analysis, and to investigate the ranges of their interspecific variability. In total, 720 pollen grains were studied. They were analysed with respect to seven quantitative features (length of the polar axis ˗ P, equatorial diameter ˗ E, length of the ectoaperture ˗ Le, exine thickness ˗ Ex, and P/E, Ex/P and Le/P ratios) and the following qualitative ones: pollen outline and exine ornamentation. The most important features were exine ornamentation (muri, lumina and margo) characters. The pollen features should be treated as auxiliary because they allowed to distinguish eight individual Salix species, and five groups of species. Statistical analysis of the studied traits indicated a high variability among the tested species. The most variable biometric features were P, E and Le, while lower variability occurred in P/E, Le/P and d/E.

Pollen morphology of selected species of Anacardiaceae and its taxonomic significance

In the present work, the pollen morphology of 22 species of Anacardiaceae was analysed, occurring in the state of Bahia, Brazil. The palynological material was obtained from specimens deposited in herbaria. The pollen grains were acetolysed, measured, illustrated and described under light and scanning electron microscopies. The quantitative data were statistically analysed according to sample size. The analysed species presented pollen grains in monads, small to medium sized, isopolar, amb circular to subtriangular, with shapes varying from oblate-spheroidal to prolate, 3-colporate, with fastigium in some species. The exine ornamentation was characterized as psilate, striate, microreticulate-striate, striato-perforate, suprastriato-infra(micro)reticulate. The pollen morphology variation confirms the eurypalynous character of the family. The attributes of the apertures and exine may collaborate in the taxonomic circumscription and provide a clarification of the phylogenetic relationships of the group.

Palynological investigations in Jasminum spp.

The present investigation was carried out at the Department of Floriculture and Landscape Architecture, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during 2017-2019. The study involved nine jasmine genotypes, four falling under the commercially cultivated types and five belonging to underutilized species or ‘lesser-known species’. The study was undertaken to investigate and document the palynological parameters of jasmines which could serve as a reliable reference for future jasmine breeding programmes. The palynological investigations were carried out using Scanning Electron Microscopy (SEM), haemocytometry, acetocarmine test, and in vitro pollen germination. The pollen morphology analysis indicated wide variation among the species for the shape of the pollen grain, ranging from tricolpate to prolate; the exine ornamentation was reticulate in all the genotypes. Pollen output was the highest in J. rigidum (28,660 pollen/flower) and the lowest in (625 pollen/ flower) in J. sambac cv. Ramanathapuram Gundumalli. The maximum pollen germination rate and pollen tube length were recorded in J. rigidum.

Pollen morphology and infrageneric classification of selected Callicarpa species (Lamiaceae) from the Philippines and Borneo

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.