Search Results (28)

Gastrodia elata is a mycoheterotrophic orchid. Three of its forms (G. elata f. glauca, G. elata f. elata, G. elata f. viridis) show distinct reproductive traits, but the cytological basis remains unclear. Using multi-timepoint morphological observation and semi-thin/ultra-thin sectioning, we systematically compared their reproductive processes from gametophyte development to seed maturation. All forms exhibited pollen wall polar differentiation (“well-developed locular side, simplified lateral sides”) following a six-stage program, with f. elata germinating fastest, f. viridis intermediate, and no germination in f. glauca. In the female gametophyte, vesicle clusters and degradation zones suggest the possibility of a two-step “chalazal degradation—micropylar localization” nuclear clearance model. Embryo development rate followed f. elata > f. glauca > f. viridis. Mature seeds stored lipid/protein bodies; f. elata uniquely contained amyloplasts and acicular phytin crystals, with form-specific seed coat traits. This study clarifies cytological differentiation, providing a basis for germplasm identification and conservation. Full article

Limonium Mill. species present a polymorphic sexual system associated with flower polymorphisms like ancillary pollen and stigma, with sexual and/or apomictic reproduction. The aim of this study was to investigate the reproductive traits, test for autonomous apomixis, and assess seed formation in triploid Limonium algarvense and Limonium daveaui. Pollen-stigma combinations were determined and the number of flowers and seeds counted. Single-seed flow cytometry was performed using seeds in three phenological stages: immature (stage I), early maturing (stage II) and mature seeds (stage III). The findings revealed that all triploid plants were self-sterile and produced seeds in the absence of pollination. Despite L. daveaui having a higher number of flowers than L. algarvense, a significantly higher ratio of seeds/flowers was observed in the latter species. Stage-dependent endosperm developmental patterns were observed, with nucleated cells present in stage II seeds with a light brown or pinkish coat, and an embryo peak and an endosperm peak with the double ploidy level. Stage III seeds, with a dark brown coat, presented only an embryo peak. Additionally, a single hexaploid endosperm peak was detected in stage I seeds, revealing early initiation of the endosperm with nucleated cells prior to embryo development. The single 6C endosperm peak was always associated with shrunken and wrinkled or underdeveloped stage I seeds but was never detected in stage II seeds. Overall, our results support reproduction via asexually formed seeds with pollen-independent endosperm formation and allow the identification of phenological development stages and seed coat morphological markers associated with single-seed flow cytometric screening patterns in apomictic species. Full article

This literature review systematizes current data on the development of triploid seedless hybrids in the Cucurbitaceae Juss family. The absence of seeds simplifies the consumption and industrial preparation of products from cucurbits. In addition, triploids showed larger plant habitus, field resistance to infections, extended shelf life, and higher fruit quality. Phenotypic differences in polyploids can stem from altered chromatin organization and gene regulation, as the nucleus must accommodate a doubled chromosome set. The triploid watermelon cultivation method developed in 1951 failed to gain traction among other crops in the gourd (Cucurbitaceae) family. The challenges of triploid seed production and use include the need for the development of tetraploid and diploid parental lines, as well as bypassing the problem of the low viability of tetraploid parent pollen and the issue of thick seed coats and underdeveloped embryos in triploids. The research findings presented in this review can be applied to the development of triploid seedless hybrids for other members of the Cucurbitaceae family. Full article

The pollen coat is the outermost layer of pollen and plays a key role in successful pollination and environmental adaptation. It consists of lipids, proteins, and phenolic compounds that protect pollen from environmental stress, promote hydration, and enable a proper interaction with the stigma. However, many questions remain unanswered, such as what the components of the pollen coat are and how they are formed, as well as how defects in the pollen coat affect the normal function of pollen. This review highlights the molecular mechanisms behind the biosynthesis and transport of pollen coat components and their contributions to pollen hydration, pollination compatibility, and fertility. Moreover, we discuss the role of selected gene families in pollen coat formation and their potential impact on agricultural breeding, paving the way for the breeding of more efficient crops. Full article

A new species of Solenopsis (Campanulaceae), S. gutermannii is described and illustrated. It is endemic to Kefalonia island, Greece, where it is very rare and localized in flat clay surfaces that are periodically submerged. This species is a very small annual hygrophyte, characterized by rosulate leaves or with slightly caulescent stems, long-pedunculated flowers, bilabiate corolla, and papillate near the throat. It exhibits close affinities primarily with S. minuta, with which it was previously identified, and additionally with S. antiphonitis, due to similarities in habit and certain flower traits. Nevertheless, several relevant morphological features serve to distinguish it from these species. Its morphology, seed coat and pollen SEM micro-sculpturing, ecology, phenology, distribution, conservation status, and taxonomic relationships are also examined. Full article

This study investigates the impact of micro- and nanocellulose coatings on the properties of wool fabrics using the solution blow spinning technique. The objective is to assess how varying cellulose sizes influence key fabric attributes, including physical properties, UV-shielding ability, air permeability and water vapour permeability, with a focus on their practical applications. Coating with microcrystalline cellulose (MCC) was found to increase the air permeability of fabric significantly, whereas coating with cellulose nanocrystals (CNCs) enhanced water vapour permeability and reduced pore size. The air permeability could relate to the breathability, and water vapour permeability could relate to the comfortability. Coated fabric with both sizes of cellulose could have different applications, like pollen filtration and printable cloth, and further functionality could be achieved by modifying the cellulose structure. This research establishes a platform for the effective application of cellulose coatings on wool fabric, offering promising advancements for textile performance and sustainability. Full article

Commercially cultivated Prunus species are commonly grown in adjacent or mixed orchards and can be infected with unique or commonly shared viruses. Apple (Malus domestica), another member of the Rosacea and distantly related to Prunus, can share the same growing regions and common pathogens. Pollen can be a major route for virus transmission, and analysis of the pollen virome in tree fruit orchards can provide insights into these virus pathogen complexes from mixed production sites. Commercial honey bee (Apis mellifera) pollination is essential for improved fruit sets and yields in tree fruit production systems. To better understand the pollen-associated virome in tree fruits, metagenomics-based detection of plant viruses was employed on bee and pollen samples collected at four time points during the peak bloom period of apricot, cherry, peach, and apple trees at one orchard site. Twenty-one unique viruses were detected in samples collected during tree fruit blooms, including prune dwarf virus (PDV) and prunus necrotic ringspot virus (PNRSV) (Genus Ilarvirus, family Bromoviridae), Secoviridae family members tomato ringspot virus (genus Nepovirus), tobacco ringspot virus (genus Nepovirus), prunus virus F (genus Fabavirus), and Betaflexiviridae family member cherry virus A (CVA; genus Capillovirus). Viruses were also identified in composite leaf and flower samples to compare the pollen virome with the virome associated with vegetative tissues. At all four time points, a greater diversity of viruses was detected in the bee and pollen samples. Finally, the nucleotide sequence diversity of the coat protein regions of CVA, PDV, and PNRSV was profiled from this site, demonstrating a wide range of sequence diversity in pollen samples from this site. These results demonstrate the benefits of area-wide monitoring through bee pollination activities and provide new insights into the diversity of viruses in tree fruit pollination ecosystems. Full article

Silique development exerts significant impacts on crop yield. CRPs (Cysteine-rich peptides) can mediate cell–cell communication during plant reproduction and development. However, the functional characterization and regulatory mechanisms of CRPs in silique development remain unclear. In this study, we identified many CRP genes downstream of the CRP gene TPD1 (TAPETUM DETERMINANT1) during silique development using a microarray assay. The novel Arabidopsis thaliana pollen-borne CRPs, the PCP-Bs (for pollen coat protein B-class) gene AtPCP-Ba, along with TPD1, are essential for silique development. The AtPCP-Ba was significantly down-regulated in tpd1 flower buds but up-regulated in OE-TPD1 flower buds and siliques. The silencing of AtPCP-Ba compromised the wider silique of OE-TPD1 plants and inhibited the morphology of OE-TPD1 siliques to the size observed in the wild type. A total of 258 CRPs were identified with the bioinformatic analysis in Arabidopsis, Brassica napus, Glycine max, Oryza sativa, Sorghum bicolor, and Zea mays. Based on the evolutionary tree classification, all CRP members can be categorized into five subgroups. Notably, 107 CRP genes were predicted to exhibit abundant expression in flowers and fruits. Most cysteine-rich peptides exhibited high expression levels in Arabidopsis and Brassica napus. These findings suggested the involvement of the CRP AtPCP-Ba in the TPD1 signaling pathway, thereby regulating silique development in Arabidopsis. Full article

Herbaria are vital resources of biodiversity education and conservation. They contain significant dried collections and botanical data of plant species that are useful for taxonomy, systematics, and plant-based applied research applications. Verbascum L. is the largest genus within the Scrophulariaceae family globally. However, the high morphological diversity within the genus poses significant challenges for accurate species delimitation. This study investigated the pollen and seed morphology of seven distinct Verbascum groups (comprising 10 taxa, including three endemics) from southeastern Anatolia using scanning electron microscopy (SEM). SEM analyses revealed that all examined taxa possessed tricolporate pollen apertures, with pollen shapes varying between prolate spheroidal and oblate spheroidal. Seeds exhibited a light brown to dark brown color, with a prismatic oblong shape and alveolate surface. The seed coat ornamentation consisted of irregular polygonal cells, densely covered with distinct vesicles. Findings demonstrate significant morphological distinctions in both pollen and seed characteristics, suggesting their utility in taxonomic discrimination within Verbascum groups. Notably, the detailed micromorphology revealed by SEM proved to be particularly valuable for classifying these taxa. These results contribute the understanding of the taxonomic diversity within Verbascum and highlight the crucial role of SEM in uncovering microstructural details for accurate species identification. Full article

Lespedeza davurica (Laxm.) is a leguminous plant with significant ecological benefits, but its embryonic development mechanism remains unclear. We investigated the flower bud differentiation, megaspore and microspore formation, gametophyte development, and embryo and endosperm development in L. davurica. Our aim was to elucidate the relationship between the external morphology and internal development processes of male and female floral organs during growth, as well as the reproductive factors influencing fruiting. The results indicated that although the pistil develops later than the stamen during flower bud differentiation, both organs mature synchronously before flowering. L. davurica pollen exhibits three germination grooves, a reticulate outer wall, and papillary structures on the anther surface. In vivo pollination experiments revealed abnormal spiral growth of L. davurica pollen tubes within the style and the occurrence of callus plugs, which may reduce the seed setting rate. The anther wall development follows the dicotyledonous type, with tetrads formed through microspore meiosis exhibiting both left–right symmetry and tetrahedral arrangements. L. davurica has a single ovule, and the embryo sac develops in the monosporic polygonum type. After dormancy, the zygote undergoes multiple divisions, progressing through spherical, heart-shaped, and torpedo-shaped embryo stages, culminating in a mature embryo. A mature seed comprises cotyledons, hypocotyl, embryo, radicle, and seed coat. Phylogenetic tree analysis reveals a close genetic relationship between L. davurica and other leguminous plants from the genera Lespedeza and Medicago. This study provides valuable insights into the regulation of flowering and hybrid breeding in leguminous plants and offers a new perspective on the development of floral organs and seed setting rates. Full article

Liquid marbles are widely known for their potential biomedical applications, especially due to their versatility and ease of preparation. In the present work, we prepared liquid marbles with various cores composed of water, agar-based hydrogels, magnetic fluids, or non-aqueous substances. As a coating material, we used biocompatible particles of plant origin, such as turmeric grains and Lycopodium pollen. Additionally, we provided marbles with magnetic properties by incorporating either magnetosomes or iron oxide nanoparticles as a powder or by injecting another magnetic fluid. Structures obtained in this way were stable and susceptible to manipulation by an external magnetic field. The properties of the magnetic components of our marbles were verified using electron paramagnetic resonance (EPR) spectroscopy and vibrating sample magnetometry (VSM). Our approach to encapsulation of active substances such as antibiotics within a protective hydrogel core opens up new perspectives for the delivery of hydrophobic payloads to the inherently hydrophilic biological environment. Additionally, hydrogel marbles enriched with magnetic materials showed promise as biocompatible heating agents under alternating magnetic fields. A significant innovation of our research was also the fabrication of composite structures in which the gel-like core was surrounded without mixing by a magnetic fluid covered on the outside by the particle shell. Our liquid marbles, especially those with a hydrogel core and magnetic content, due to the ease of preparation and favorable properties, have great potential for biomedical use. The fact that we were able to simultaneously produce, functionalize (by filling with predefined cargo), and manipulate (by means of an external magnetic field) several marbles also seems to be important from an application point of view. Full article

The commercial cultivation of herbicide-resistant (HR) transgenic soybeans (Glycine max L. Merr.) raises great concern that transgenes may introgress into wild soybeans (Glycine soja Sieb. et Zucc.) via pollen-mediated gene flow, which could increase the ecological risks of transgenic weed populations and threaten the genetic diversity of wild soybean. To assess the fitness of hybrids derived from transgenic HR soybean and wild soybean, the F₂ and F₃ descendants of crosses of the HR soybean line T14R1251-70 and two wild soybeans (LNTL and JLBC, which were collected from LiaoNing TieLing and JiLin BaiCheng, respectively), were planted along with their parents in wasteland or farmland soil, with or without weed competition. The fitness of F₂ and F₃ was significantly increased compared to the wild soybeans under all test conditions, and they also showed a greater competitive ability against weeds. Seeds produced by F₂ and F₃ were superficially similar to wild soybeans in having a hard seed coat; however, closer morphological examination revealed that the hard-seededness was lower due to the seed coat structure, specifically the presence of thicker hourglass cells in seed coat layers and lower Ca content in palisade epidermis. Hybrid descendants containing the cp4-epsps HR allele were able to complete their life cycle and produce a large number of seeds in the test conditions, which suggests that they would be able to survive in the soil beyond a single growing season, germinate, and grow under suitable conditions. Our findings indicate that the hybrid descendants of HR soybean and wild soybean may pose potential ecological risks in regions of soybean cultivation where wild soybean occurs. Full article

A pollen grain is a unique haploid organism characterized by a special composition and structure. The pollen of angiosperms and gymnosperms germinate in fundamentally similar ways, but the latter also have important features, including slow growth rates and lower dependence on female tissues. These features are, to some extent, due to the properties of pollen lipids, which perform a number of functions during germination. Here, we compared the absolute content and the fatty acid (FA) composition of pollen lipids of two species of flowering plants and spruce using GC-MS. The FA composition of spruce pollen differed significantly, including the predominance of saturated and monoene FAs, and a high proportion of very-long-chain FAs (VLCFAs). Significant differences between FAs from integumentary lipids (pollen coat (PC)) and lipids of gametophyte cells were found for lily and tobacco, including a very low unsaturation index of the PC. The proportion of VLCFAs in the integument was several times higher than in gametophyte cells. We found that the absolute content of lipids in lily pollen is almost three times higher than in tobacco and spruce pollen. For the first time, changes in the FA composition were analyzed during pollen germination in gymnosperms and angiosperms. The stimulating effect of H₂O₂ on spruce germination also led to noticeable changes in the FA content and composition of growing pollen. For tobacco in control and test samples, the FA composition was stable. Full article

Healthy agroecosystems are dependent on a complex web of factors and inter-species interactions. Flowers are hubs for pathogen transmission, including the horizontal or vertical transmission of plant-viruses and the horizontal transmission of bee-viruses. Pollination by the European honey bee (Apis mellifera) is critical for industrial fruit production, but bees can also vector viruses and other pathogens between individuals. Here, we utilized commercial honey bee pollination services in blueberry (Vaccinium corymbosum) farms for a metagenomics-based bee and plant virus monitoring system. Following RNA sequencing, viruses were identified by mapping reads to a reference sequence database through the bioinformatics portal Virtool. In total, 29 unique plant viral species were found at two blueberry farms in British Columbia (BC). Nine viruses were identified at one site in Ontario (ON), five of which were not identified in BC. Ilarviruses blueberry shock virus (BlShV) and prune dwarf virus (PDV) were the most frequently detected viruses in BC but absent in ON, while nepoviruses tomato ringspot virus and tobacco ringspot virus were common in ON but absent in BC. BlShV coat protein (CP) nucleotide sequences were nearly identical in all samples, while PDV CP sequences were more diverse, suggesting multiple strains of PDV circulating at this site. Ten bee-infecting viruses were identified, with black queen cell virus frequently detected in ON and BC. Area-wide bee-mediated pathogen monitoring can provide new insights into the diversity of viruses present in, and the health of, bee-pollination ecosystems. This approach can be limited by a short sampling season, biased towards pollen-transmitted viruses, and the plant material collected by bees can be very diverse. This can obscure the origin of some viruses, but bee-mediated virus monitoring can be an effective preliminary monitoring approach. Full article

IgE-mediated allergic reaction occurs in response to harmless environmental compounds, such as tree and grass pollen, fragments of household microorganisms, etc. To date, the only way to treat IgE-mediated allergy is allergen-specific immunotherapy (ASIT), which consists of a prolonged subcutaneous administration of allergen extracts or recombinant proteins. The long duration of the treatment, the cost and the risk of life-threatening adverse reactions are the main limiting factors for ASIT. The aim of this work was to develop allergen proteins encapsulated in chitosan-based microparticles that can be safely administered at high doses and in a rash protocol. The egg white allergen, Gal d 1 protein, was used as a model antigen. The protein was packed into core–shell type microparticles (MPs), in which the core was formed with succinyl chitosan conjugated to Gal d 1, subsequently coated with a shell formed by quaternized chitosan. The obtained core–shell MPs containing Gal d 1 in the core (Gal-MPs) were non-toxic to macrophage and fibroblast cell lines. At the same time, Gal-MPs were quickly engulfed by bone marrow-derived dendritic cells or RAW264.7 macrophage cells, as was visualized using flow cytometry and confocal microscopy. Encapsulated Gal d 1 was not recognized by Gal d 1-specific IgE in ELISA. Female BALB/c mice were immunized with Gal-MPs subcutaneously three times a week for 2 weeks. Immunization of mice resulted in IgG titers 1250 ± 200 without IgE production. Allergy in control and vaccinated mice was induced by low-dose Gal d 1 injections in the withers of mice. IgE was induced in control-sensitized but not in the vaccinated mice. Thus, preventive vaccination with the encapsulated allergens is safe and rapid; it significantly reduces the risk of IgE production induced by respiratory and oral allergens. Full article