RESUMO
Chrysolaena flexuosa (Sims.) H. Rob. is a South American species in the tribe Vernonieae, with potential ornamental value: it has attractive inflorescences, is suitable for pot cultivation, and its cypselae are useful for dried flower arrangements. Apart from studies on the growth dynamics of this species under cultivation, chromosome number, DNA content, ploidy level, size, pollen viability, and the characterization of phenotypic and genetic variability, it is noteworthy that other aspects regarding the floral architecture, reproductive mode, and gametophyte formation of C. flexuosa have not yet been studied. For this reason, our study encompasses a floral morphoanatomical survey and a comprehensive assessment of gametophyte development in the species. As a result of this study, we report new floral morphotypes, confirming that the morphological variability of the species might be greater than speculated. The morphoanatomy of the androecium and gynoecium and the male and female gametophyte developmental characteristics are uniform in all the populations studied despite the different ploidy levels. Chrysolaena flexuosa has five tetrasporangiate stamens of the dicotyledonous type of development; all the populations studied displayed a unilocular inferior ovary with a single anatropous, unitegumented, and tenuinucellar ovule. Given that all the embryo sacs observed were of the Polygonum-type development regardless of the ploidy level, we infer that the populations analyzed are fertile and undergo sexual reproduction. Our results not only contribute further research in the field of breeding systems and propagation of this species, but also promote the successful introduction of C. flexuosa to the plant ornamental market.
Assuntos
Asteraceae , Flores , Flores/anatomia & histologia , Flores/crescimento & desenvolvimento , Asteraceae/anatomia & histologia , Asteraceae/crescimento & desenvolvimento , Asteraceae/genética , Pólen/anatomia & histologia , Pólen/ultraestruturaRESUMO
A method development for determination of neonicotinoid residues in honey samples was developed. The proposed methodology consisted in QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe). That was used for sample preparation and UHPLC/UV (ultra-performance liquid chromatography with ultraviolet detection) utilized for chromatographic analysis. The developed method proved to be sensitive, with LOD (Limit of detection) value in the range of 60.80 to 80.98 ng/g hence LOQ (Limit of quantification) value was in the range of 184.26 to 245.40 ng/g. The method has tested on Polish honey and applied to honey from various countries (Bulgaria, Czech Republic, France, Greece, Italy, Portugal, Romania, Australia, Brazil, Cameroon, Russia, USA and Turkey). Several honey types were tested, while physicochemical properties of all honeys and were investigated. The methodology for general characterization of pollen grains originated from selected plants, to confirm the type of honey was also presented. There was a total lack of the mentioned neonicotinoids in sunflower honey. Except of this, only two samples of rapeseed and two samples of acacia honey (from Poland and Romania) were neonicotinoids free. In 19 samples the targeted pesticides were detected above LOQ. In all other investigated samples, the neonicotinoids were found at least at the LOD or LOQ level.
Assuntos
Mel/análise , Neonicotinoides/análise , Animais , Austrália , Abelhas , Brasil , Fenômenos Químicos , Cromatografia Líquida de Alta Pressão , Europa (Continente) , Flores/química , Inseticidas/análise , Inseticidas/química , Limite de Detecção , Neonicotinoides/química , Polônia , Pólen/química , Pólen/ultraestrutura , Polinização , Estados UnidosRESUMO
Nature provides remarkable examples of mass-produced microscale particles with structures and chemistries optimized by evolution for particular functions. Synthetic chemical tailoring of such sustainable biogenic particles may be used to generate new multifunctional materials. Herein, we report a facile method for the synthesis of hybrid nano/microstructures Ag-Fe3O4 based on Dimorphotheca ecklonis pollen grains as bio-template. Silver nanoparticles was biosynthesized using pollen grains as a reduction and stabilization agent as well as a bio-template promoting the adhesion of silver nanoparticles to pollen surface. Fe3O4 nanoparticles were synthesized by co-precipitation method from FeSO4. Hybrid nano/microstructures Ag-Fe3O4 based on Dimorphotheca ecklonis pollen grains as bio-template were obtained and characterized using Scanning Electron Microscopy and Transmission Electron Microscopy to study the morphology and structure; Energy-Dispersive X-ray Spectroscopy to determine the chemical composition distribution; and Confocal Fluorescence Microscopy to demonstrate the fluorescence properties of hybrid nano-microstructures. Furthermore, these hybrid nano-microstructures have been studied by Surface-Enhanced Raman Scattering (SERS), using methylene blue as a target molecule; the hybrid nano-microstructures have shown 14 times signal amplification.
Assuntos
Asteraceae , Vias Biossintéticas , Compostos Férricos/química , Nanopartículas Metálicas/química , Pólen/química , Prata/química , Análise Espectral Raman , Azul de Metileno , Microscopia Eletroquímica de Varredura , Microscopia Eletrônica de Transmissão , Pólen/ultraestrutura , Espectrometria por Raios XRESUMO
Cyperaceae representatives present peculiar microsporogenesis and microgametogenesis, which raises the question of how regular the sedge pollen is. In order to answer this question, preanthesis pollen grains of Cyperaceae individuals were analyzed under different tools such as light and transmission electron microscopy, which included cytochemistry and immunogold procedures. The results showed that maturing pollen in Cyperaceae presents some unusual endomembrane behaviors. Endoplasmic reticulum and dictyosomes are concerned in classic secretion pathways in vegetative cells, and possibly the late breakdown of degenerative microspores. However, cortical and concentric endoplasmic reticulum are also present and are possibly related to other functions aside the biosynthetic pathway. Unconventional secretion of large membrane-bound bodies containing cell wall precursors was also observed and confirmed by immunogold. However, since these bodies most likely receive material from dictyosomes, as observed in silver nitrate reaction, the "unconventional" status of this secretion is debatable. Reports of the literature show that these unusual endomembrane formations are not exclusive of the sedge pollen, but little attention have been given to them so far. This could represent an opportunity to re-examine our understanding on the endomembrane system in pollen cells in general.
Assuntos
Cyperaceae , Retículo Endoplasmático/ultraestrutura , Gametogênese Vegetal , Complexo de Golgi/ultraestrutura , Pólen/ultraestruturaRESUMO
Microvesicles are key players in cellular communication. As glandular secretions present a rich source of active exosomes, we hypothesized that exosome-like vesicles are present in Apis mellifera hypopharyngeal gland secretomal products (honey, royal jelly and bee pollen), and participate in their known antibacterial and pro-regenerative effects. We developed an isolation protocol based on serial centrifugation and ultracentrifugation steps and demonstrated the presence of protein-containing exosome-like vesicles in all three bee-derived products. Assessing their antibacterial properties, we found that exosome-like vesicles had bacteriostatic, bactericidal and biofilm-inhibiting effects on Staphylococcus aureus Furthermore, we demonstrated that mesenchymal stem cells (MSCs) internalize bee-derived exosome-like vesicles and that these vesicles influence the migration potential of the MSCs. In an in vitro wound-healing assay, honey and royal jelly exosome-like vesicles increased migration of human MSCs, demonstrating their inter-kingdom activity. In summary, we have discovered exosome-like vesicles as a new, active compound in bee pollen, honey and royal jelly.
Assuntos
Antibacterianos/farmacologia , Abelhas/metabolismo , Exossomos/metabolismo , Ácidos Graxos/química , Mel , Pólen/química , Regeneração/efeitos dos fármacos , Animais , Movimento Celular/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Exossomos/efeitos dos fármacos , Humanos , Pólen/ultraestruturaRESUMO
Eremitis, Pariana, and Parianella are herbaceous bamboos (tribe Olyreae) included in the subtribe Parianinae, which is characterized by the presence of fimbriae at the apex of the leaf sheaths and exclusively spiciform synflorescences. We analyzed 43 samples of herbaceous and woody bamboos in order to infer relationships within the Parianinae, based on combined data from the nuclear ribosomal internal transcribed spacer (ITS) and plastid DNA (rpl32-trnL and trnD-trnT spacers). Bayesian inference, maximum likelihood, and maximum parsimony methods were applied, and macro- and micromorphological aspects were also analyzed, including the ectexine patterns of pollen grains. Parianinae is represented by three well-supported lineages in our analyses: (1) Parianella, endemic to southern Bahia, Brazil; (2) Pariana sensu stricto with a broad distribution in southern Central America and northern South America, especially in the Amazon region; and (3) Eremitis, endemic to the Brazilian Atlantic Forest, from the states of Pernambuco to Rio de Janeiro, including one species previously described as a member of Pariana. Our molecular phylogeny showed that Pariana, as historically circumscribed, is not monophyletic, by recovering Pariana sensu stricto as strongly supported and sister to Eremitisâ¯+â¯Pariana multiflora, with Parianella sister to the Pariana-Eremitis clade. Morphological features of their synflorescences and differences in ectexine patterns characterize each lineage. Based on all these characters and the phylogenetic results, Pariana multiflora, endemic to the state of Espírito Santo, Brazil, is transferred to Eremitis.
Assuntos
Poaceae/classificação , Teorema de Bayes , Brasil , Núcleo Celular/genética , América Central , DNA de Plantas/química , Filogenia , Plastídeos/genética , Poaceae/anatomia & histologia , Poaceae/genética , Poaceae/ultraestrutura , Pólen/ultraestrutura , Análise de Sequência de DNA , América do SulRESUMO
Perfect flowers of Maytenus obtusifolia have partial sterility of pollen grains, resulting in collapsed and developed free microspores. However, the cellular events resulting in partial male sterility have not been determined. In pistillate flowers of this species, male sterility is related to the premature programmed cell death (PCD) in tapetum and sporogenic cells. The process occurs through autophagy via macroautophagy and massive autophagy and is associated with sporophytic cytoplasmic male sterility (CMS). Here, we characterised the development of pollen grains and investigated the cellular events that result in tapetum cells and free microspores PCD in perfect flowers, using light and transmission electron microscopy combined with the TUNEL (Terminal deoxynucleotidyl transferase mediated dUDP end-Labeling) assay and the ZIO (Zinc iodide-osmium tetroxide) method. Pollen grain development in perfect flowers was divided into eight developmental stages based on the characteristics of the pollen grains. Tapetum cells undergo PCD at the free microspore stage, through a macroautophagic process, by formation of autophagosomes and by autophagosomes giving rise to lytic vacuoles at maturity. In the final stage of PCD, massive autophagy occurs by rupture of the tonoplast. The development of viable and inviable microspores diverges at the vacuolated microspore stage, when PCD occurs in some free microspores, causing interruption of pollen development through necrosis. These events result in the observed partial male sterility. Viable microspores undergo mitosis and develop into tricellular pollen grains. Male sterility in hermaphrodite individuals is here interpreted as gametophytic CMS.
Assuntos
Celastraceae/crescimento & desenvolvimento , Celastraceae/fisiologia , Infertilidade das Plantas/fisiologia , Pólen/crescimento & desenvolvimento , Apoptose , Autofagossomos/metabolismo , Autofagossomos/ultraestrutura , Celastraceae/citologia , Celastraceae/ultraestrutura , Gametogênese Vegetal , Pólen/citologia , Pólen/ultraestruturaRESUMO
The genus Passiflora is the most diversified of the Passifloraceae, and its palynology presents wide morphological variability. The objective of the study was to evaluate the pollen morphology of 18 Passiflora species in order to identify informative pollinic characteristics to contribute to the taxonomic classification of the genus. The morphology of the pollen grains and the exine structure were investigated using light microscopy and scanning electron microscopy. Differences in the pollen morphology were found in the studied species, mainly in terms of shape, pollen aperture and ornamentation pattern of the exine. Most of the species belonging to the subgenus Passiflora presented ornamented 6-syncolpate pollen grains with an oblate-spheroidal shape and an exine with large lumens. In the subgenus Decaloba the pollen grains were 6-colporate, 12-colpate and 12-colporate, with subprolate to prolate-spheroidal shape, as well as an exine with smaller lumen size and few ornamented. The pollen morphology of the species of the subgenera Passiflora and Decaloba has shown palynological characteristics that have specific diagnostic value, thus allowing a better understanding of the taxonomy of the genus Passiflora.
Assuntos
Passiflora/classificação , Pólen/classificação , Microscopia Eletrônica de Varredura , Passiflora/anatomia & histologia , Passiflora/ultraestrutura , Pólen/anatomia & histologia , Pólen/ultraestrutura , Especificidade da EspécieRESUMO
Pollen morphology characterization is important in taxonomy, conservation and plant breeding, and pollen viability studies can support breeding programs. This study investigated pollen morphology and male fertility in 18 species of Bromeliaceae with ornamental potential. For morphological characterization, pollen grains were acetolyzed and characterization of exine was done using scanning and transmission electron microscopy. Pollen viability was investigated by in vitro germination and histochemical tests. Species belonging to Aechmea and Ananas genera presented medium size pollen, except for Ae. fasciata, with large pollen. Al. nahoumii, P. sagenarius and the Vriesea species analyzed showed large pollen, except for V. carinata, with very large pollen. Pollen of Aechmea, Ananas and P. sagenarius presented bilateral symmetry, diporate, exine varying from tectate to semitectate. Al. nahoumii and Vriesea species presented pollen with bilateral symmetry, monocolpate; exine was semitectate, reticulate and heterobrochate. Germination percentage and tube growth were greater in SM and BKM media. Histochemical tests showed pollen viability above 70% for all species, except for Ananas sp. (40%). Pollen morphology is important for the identification of species, especially in this family, which contains a large number of species. High rates of viability favor fertilization and seed production, essential for efficient hybrid production and conservation.
Assuntos
Bromeliaceae/fisiologia , Pólen/fisiologia , Bromeliaceae/classificação , Bromeliaceae/ultraestrutura , Imuno-Histoquímica , Microscopia Eletrônica , Pólen/crescimento & desenvolvimento , Pólen/ultraestruturaRESUMO
ABSTRACT Pollen morphology characterization is important in taxonomy, conservation and plant breeding, and pollen viability studies can support breeding programs. This study investigated pollen morphology and male fertility in 18 species of Bromeliaceae with ornamental potential. For morphological characterization, pollen grains were acetolyzed and characterization of exine was done using scanning and transmission electron microscopy. Pollen viability was investigated by in vitro germination and histochemical tests. Species belonging to Aechmea and Ananas genera presented medium size pollen, except for Ae. fasciata, with large pollen. Al. nahoumii, P. sagenarius and the Vriesea species analyzed showed large pollen, except for V. carinata, with very large pollen. Pollen of Aechmea, Ananas and P. sagenarius presented bilateral symmetry, diporate, exine varying from tectate to semitectate. Al. nahoumii and Vriesea species presented pollen with bilateral symmetry, monocolpate; exine was semitectate, reticulate and heterobrochate. Germination percentage and tube growth were greater in SM and BKM media. Histochemical tests showed pollen viability above 70% for all species, except for Ananas sp. (40%). Pollen morphology is important for the identification of species, especially in this family, which contains a large number of species. High rates of viability favor fertilization and seed production, essential for efficient hybrid production and conservation.