Scanning electron microscope in carpological studies

Spośród organów generatywnych roślin kwiatowych nasiona i owoce należą nadal do najmniej poznanych. Przetrwalnikowy chara­kter i związana z tym konieczność diagnozowa­nia tych diaspor oraz bogata ich różnorodność morfologiczno-anatomiczna stały się podstawą wyodrębnienia w botanice dziedziny zwanej karpologią 117, 18, 49, 52, 62, 70, 74). Rozwój karpologii, zwłaszcza w drugiej połowie XX wieku, wynika przede wszystkim z ciągłego udoskonalania technik badawczych, co pozwoli­ło przejść od klasycznej metody obserwacyjno­opisowej w mikroskopie świetlnym (LM) do metod pełnej interpretacji na podstawie obrazów elektronogramów) z transmisyjnego oraz ska­ningowego mikroskopu elektronowego (TEM, SEM)[...

Comparative analysis of structure of allopolyploid liverwort Pellia borealis and ancestral taxa

Pellia borealis Lorb. is a simple thalloid liverwort that originated after hybridization between two allopatric taxa: Pellia epiphylla N and Pellia epiphylla S. The morphological and anatomical similarity of Pellia species along with its plasticity cause difficulties in clearly defining the species. Species from the Pellia epiphylla complex differ from the remaining Pellia species by bisexuality. Microstructure of the gametophytes of all three taxa and sporophytes of P. borealis and P. epiphylla S was investigated using scanning electron microscopy. As a result of these observations, some new diagnostic characters between analyzed taxa were discovered. P. borealis shows a different pattern of papillae distribution on the dorsal surface of the thallus compared to ancestral taxa and has larger cells. P. epiphylla N was distinguished by the localization and shape of archegonia. Comparison of P. borealis and P. epiphylla S capsule surface showed a significantly different microstructure

Biodegradation of Pre-Aged Modified Polyethylene Films

In the environment plastics decompose under the influence of different abiotic and biotic factors. The abiotic factors such as radiation, temperature, humidity, chemical pollution and wind can act synergistically or antagonistically causing various types of structural and chemical changes in the polymer. Microorganisms, especially bacteria or fungi, play a crucial role in biological degradation of polymers. Scanning electron microscopy (SEM) is an invaluable tool for polymer analysis, since it is extensively used to study changes in the texture and composition of biodegradable polymer materials exposed to various environmental factors. It allows for the exploration of large surfaces with excellent resolution of topographic features

Biodegradation of Pre-Aged Modified Polyethylene Films

In the environment plastics decompose under the influence of different abiotic and biotic factors. The abiotic factors such as radiation, temperature, humidity, chemical pollution and wind can act synergistically or antagonistically causing various types of structural and chemical changes in the polymer. Microorganisms, especially bacteria or fungi, play a crucial role in biological degradation of polymers. Scanning electron microscopy (SEM) is an invaluable tool for polymer analysis, since it is extensively used to study changes in the texture and composition of biodegradable polymer materials exposed to various environmental factors. It allows for the exploration of large surfaces with excellent resolution of topographic features

Unmethyl-esterified homogalacturonan and extensins seal Arabidopsis graft union

Background: Grafting is a technique widely used in horticulture. The processes involved in grafting are diverse, and the technique is commonly employed in studies focusing on the mechanisms that regulate cell differentiation or response of plants to abiotic stress. Information on the changes in the composition of the cell wall that occur during the grafting process is scarce. Therefore, this study was carried out for analyzing the composition of the cell wall using Arabidopsis hypocotyls as an example. During the study, the formation of a layer that covers the surface of the graft union was observed. So, this study also aimed to describe the histological and cellular changes that accompany autografting of Arabidopsis hypocotyls and to perform preliminary chemical and structural analyses of extracellular material that seals the graft union. Results: During grafting, polyphenolic and lipid compounds were detected, along with extracellular deposition of carbohydrate/protein material. The spatiotemporal changes observed in the structure of the extracellular material included the formation of a fibrillar network, polymerization of the fibrillar network into a membranous layer, and the presence of bead-like structures on the surface of cells in established graft union. These bead-like structures appeared either “closed” or “open”. Only three cell wall epitopes, namely: LM19 (un/low-methyl-esterified homogalacturonan), JIM11, and JIM20 (extensins), were detected abundantly on the cut surfaces that made the adhesion plane, as well as in the structure that covered the graft union and in the bead-like structures, during the subsequent stages of regeneration. Conclusions: To the best of our knowledge, this is the first report on the composition and structure of the extracellular material that gets deposited on the surface of graft union during Arabidopsis grafting. The results showed that unmethyl-esterified homogalacturonan and extensins are together involved in the adhesion of scion and stock, as well as taking part in sealing the graft union. The extracellular material is of importance not only due to the potential pectin–extensin interaction but also due to its origin. The findings presented here implicate a need for studies with biochemical approach for a detailed analysis of the composition and structure of the extracellular material

Fate of neutral-charged gold nanoparticles in the roots of the Hordeum vulgare L. cultivar Karat

Nanoparticles (NPs) have a significant impact on the environment and living organisms. The influence of NPs on plants is intensively studied and most of the data indicate that NPs can penetrate into plants. The studies presented here were performed on the roots of Hordeum vulgare L. seedlings using neutral-charge gold nanoparticles (AuNPs) of different sizes. In contrast to the majority of the published data, the results presented here showed that during the culture period, AuNPs: 1/did not enter the root regardless of their size and concentration, 2/that are applied directly into the cells of a root do not move into neighbouring cells. The results that were obtained indicate that in order to extend our knowledge about the mechanisms of the interactions between NPs and plants, further studies including, among others, on different species and a variety of growth conditions are needed

Effect of Pseudomonas moorei KB4 Cells’ Immobilisation on Their Degradation Potential and Tolerance towards Paracetamol

Pseudomonas moorei KB4 is capable of degrading paracetamol, but high concentrations of this drug may cause an accumulation of toxic metabolites. It is known that immobilisation can have a protective effect on bacterial cells; therefore, the toxicity and degradation rate of paracetamol by the immobilised strain KB4 were assessed. Strain KB4 was immobilised on a plant sponge. A toxicity assessment was performed by measuring the concentration of ATP using the colony-forming unit (CFU) method. The kinetic parameters of paracetamol degradation were estimated using the Hill equation. Toxicity analysis showed a protective effect of the carrier at low concentrations of paracetamol. Moreover, a pronounced phenomenon of hormesis was observed in the immobilised systems. The obtained kinetic parameters and the course of the kinetic curves clearly indicate a decrease in the degradation activity of cells after their immobilisation. There was a delay in degradation in the systems with free cells without glucose and immobilised cells with glucose. However, it was demonstrated that the immobilised systems can degrade at least ten succeeding cycles of 20 mg/L paracetamol degradation. The obtained results indicate that the immobilised strain may become a useful tool in the process of paracetamol degradation

Whole Mount in situ Localization of miRNAs and mRNAs During Somatic Embryogenesis in Arabidopsis

Somatic embryogenesis (SE) results from the transition of differentiated plant somatic cells into embryogenic cells that requires the extensive reprogramming of the somatic cell transcriptome. Commonly, the SE-involved genes are identified by analyzing the heterogeneous population of explant cells and thus, it is necessary to validate the expression of the candidate genes in the cells that are competent for embryogenic transition. Here, we optimized and implemented the whole mount in situ hybridization (WISH) method (Bleckmann and Dresselhaus, 2016; Dastidar et al., 2016) in order to analyze the spatiotemporal localization of miRNAs (miR156, miR166, miR390, miR167) and mRNAs such as WOX5 and PHABULOSA-target of miR165/166 during the SE that is induced in Arabidopsis explants. This study presents a detailed step-by-step description of the WISH procedure in which DIG-labeled LNA and RNA probes were used to detect miRNAs and mRNAs, respectively. The usefulness of the WISH in the functional analysis of the SE-involved regulatory pathways is demonstrated and the advantages of this method are highlighted: (i) the ability to analyze intact non-sectioned plant tissue; (ii) the specificity of transcript detection; (iii) the detection of miRNA; and (iv) a semi-quantitative assessment of the RNA abundance

Using Plantago major and Plantago lanceolata in environmental pollution research in an urban area of Southern Poland

The aim of this study was to perform a complex assessment of changes in the elements of an ecosystem that are caused by environmental pollution in industrial and urban biotopes. The study focused on three sites: a park, a road and the site of the metallurgical plant “Pokój” in the city of Ruda Śląska (Southern Poland), which are each under a different level of anthropogenic load. Soil and plant material samples (Plantago major and Plantago lanceolata leaves) were investigated by performing biochemical, ecophysiological and scanning electron microscopy (SEM) analyses. A significant difference was observed in all of the study samples. The content of Pb, Zn and Cd in the soil samples that had been collected at the site of the metallurgical plant exceeded the permitted limits (Cd > 4 mg kg−1, Pb > 100 mg kg−1, Zn > 300 mg kg−1). The content of Fe, Mn, Pb, Cd and Zn in the plant material was much higher in unwashed samples than in washed samples. The concentrations of potentially toxic elements (PTEs) were below the permitted level in the leaves of Plantago lanceolata for Cd (> 5 mg kg−1) and in the leaves of Plantago major for Zn (> 100 mg kg−1). The SEM observations revealed a significant decrease in the stomata pore length (SPL) in the Plantago lanceolata leaves that had been collected at the road site compared with the plants from the park site. The elemental content on the leaf surface was also determined using X-ray microanalysis. The total chlorophyll (Chl) content, ascorbic acid (AA), proline, guaiacol peroxidase (GPX) activity, pH, relative water content (RWC) and air pollution tolerance index (APTI) were evaluated. The APTI for the investigated species ranged from 5.6 to 7.4, which demonstrated that the studied plant species are sensitive to air pollutants

Spatial distribution of selected chemical cell wall components in the embryogenic callus of Brachypodium distachyon

Brachypodium distachyon L. Beauv. (Brachypodium) is a species that has become an excellent model system for gaining a better understanding of various areas of grass biology and improving plant breeding. Although there are some studies of an in vitro Brachypodium culture including somatic embryogenesis, detailed knowledge of the composition of the main cell wall components in the embryogenic callus in this species is missing. Therefore, using the immunocytochemical approach, we targeted 17 different antigens of which five were against the arabinogalactan proteins (AGP), three were against extensins, six recognised pectic epitopes and two recognised hemicelluloses. These studies were complemented by histological and scanning electron microscopy (SEM) analyses. We revealed that the characteristic cell wall components of Brachypodium embryogenic calli are AGP epitopes that are recognised by the JIM16 and LM2 antibodies, an extensin epitope that is recognised by the JIM11 antibody and a pectic epitopes that is recognised by the LM6 antibody. Furthermore, we demonstrated that AGPs and pectins are the components of the extracellular matrix network in Brachypodium embryogenic culture. Additionally, SEM analysis demonstrated the presence of an extracellular matrix on the surface of the calli cells. In conclusion, the chemical compositions of the cell walls and ECMSN of Brachypodium callus show spatial differences that correlate with the embryogenic character of the cells. Thus, the distribution of pectins, AGPs and hemicelluloses can be used as molecular markers of embryogenic cells. The presented data extends the knowledge about the chemical composition of the embryogenic callus cells of Brachypodiu