Comparative in situ analysis reveals the dynamic nature of sclerenchyma cell walls of the fern Asplenium rutifolium.

Background And Aims: A key structural adaptation of vascular plants was the evolution of specialized vascular and mechanical tissues, innovations likely to have generated novel cell wall architectures. While collenchyma is a strengthening tissue typically found in growing organs of angiosperms, a similar tissue occurs in the petiole of the fern Asplenium rutifolium.

Methods: The in situ cell wall (ultra)structure and composition of this tissue was investigated and characterized mechanically as well as structurally through nano-indentation and wide-angle X-ray diffraction, respectively.

The complete chloroplast genome sequence of (sw.) C. Y. Yang in Lycopodiaceae.

(Sw.) C. Y.

Antibody-based screening of cell wall matrix glycans in ferns reveals taxon, tissue and cell-type specific distribution patterns.

Background: While it is kno3wn that complex tissues with specialized functions emerged during land plant evolution, it is not clear how cell wall polymers and their structural variants are associated with specific tissues or cell types. Moreover, due to the economic importance of many flowering plants, ferns have been largely neglected in cell wall comparative studies.

Results: To explore fern cell wall diversity sets of monoclonal antibodies directed to matrix glycans of angiosperm cell walls have been used in glycan microarray and in situ analyses with 76 fern species and four species of lycophytes.

Comparative glycan profiling of Ceratopteris richardii 'C-Fern' gametophytes and sporophytes links cell-wall composition to functional specialization.

Background And Aims: Innovations in vegetative and reproductive characters were key factors in the evolutionary history of land plants and most of these transformations, including dramatic changes in life cycle structure and strategy, necessarily involved cell-wall modifications. To provide more insight into the role of cell walls in effecting changes in plant structure and function, and in particular their role in the generation of vascularization, an antibody-based approach was implemented to compare the presence and distribution of cell-wall glycan epitopes between (free-living) gametophytes and sporophytes of Ceratopteris richardii 'C-Fern', a widely used model system for ferns.

Methods: Microarrays of sequential diamino-cyclohexane-tetraacetic acid (CDTA) and NaOH extractions of gametophytes, spores and different organs of 'C-Fern' sporophytes were probed with glycan-directed monoclonal antibodies.

Ceratopteris richardii (C-fern): a model for investigating adaptive modification of vascular plant cell walls.

Plant cell walls are essential for most aspects of plant growth, development, and survival, including cell division, expansive cell growth, cell-cell communication, biomechanical properties, and stress responses. Therefore, characterizing cell wall diversity contributes to our overall understanding of plant evolution and development. Recent biochemical analyses, concomitantly with whole genome sequencing of plants located at pivotal points in plant phylogeny, have helped distinguish between homologous characters and those which might be more derived.

Critical phases in the seed development of common juniper (Juniperus communis).

Common juniper (Juniperus communis L.) populations in northwest European lowlands are currently declining in size and number. An important cause of this decline is a lack of natural regeneration.

Flow cytometry confirms reticulate evolution and reveals triploidy in Central European Diphasiastrum taxa (Lycopodiaceae, Lycophyta).

Background And Aims: Interspecific Diphasiastrum hybrids have been assumed to be homoploid and to produce well-formed spores serving sexual reproduction. If this were the case, forms intermediate between hybrids and parents or hybrid swarms should be expected. The purpose of this study was: (1) to check whether homoploidy consistently applies to the three hybrids throughout their Central European range; (2) to examine whether their genome sizes confirm their parentage as assumed by morphology; and (3) to perform a screening for detection of ploidy levels other than diploid and variation in DNA content due to backcrossing.

An extensin-rich matrix lines the carinal canals in Equisetum ramosissimum, which may function as water-conducting channels.

Background And Aims: The anatomy of Equisetum stems is characterized by the occurrence of vallecular and carinal canals. Previous studies on the carinal canals in several Equisetum species suggest that they convey water from one node to another.

Methods: Cell wall composition and ultrastructure have been studied using immunocytochemistry and electron microscopy, respectively.

Ultrastructure and composition of cell wall appositions in the roots of Asplenium (Polypodiales).

Cell wall appositions (CWAs), formed by the deposition of extra wall material at the contact site with microbial organisms, are an integral part of the response of plants to microbial challenge. Detailed histological studies of CWAs in fern roots do not exist. Using light and electron microscopy we examined the (ultra)structure of CWAs in the outer layers of roots of Asplenium species.

Non-lignified helical cell wall thickenings in root cortical cells of Aspleniaceae (Polypodiales): histology and taxonomical significance.

Background And Aims: Extraxylary helical cell wall thickenings in vascular plants are not well documented, except for those in orchid velamen tissues which have been studied extensively. Reports on their occurrence in ferns exist, but detailed information is missing. The aim of this study is to focus on the broad patterns of structure and composition and to study the taxonomic occurrence of helical cell wall thickenings in the fern family Aspleniaceae.

The base number of 'loxoscaphoid' Asplenium species and its implication for cytoevolution in Aspleniaceae.

Background And Aims: 'Loxoscaphoid' Asplenium species are morphologically a remarkably distinct group of Aspleniaceae. Except for two preliminary chromosome counts of Asplenium theciferum, the cytology of this group of species has, however, been largely unstudied.

Methods: Chromosome counts were obtained by acetocarmine squash preparations of one mitotic cell and several meiotic cells.

A new preparation method to study fresh plant structures with X-ray computed tomography.

Since the development of X-ray computed tomography as a medical diagnostic tool, it was adapted and extended for many scientific applications, including plant structure research. As for many biological studies, sample preparation is of major importance to obtain good-quality images. Therefore, we present a new preparation method for fresh material which includes critical point drying and heavy metal staining.

Intercellular pectic protuberances in Asplenium: new data on their composition and origin.

Background And Aims: Projections of cell wall material into the intercellular spaces between parenchymatic cells have been observed since the mid-19th century. Histochemical staining suggested that these intercellular protuberances are probably pectic in nature, but uncertainties about their origin, composition and biological function(s) have remained.

Methods: Using electron and light microscopy, including immunohistochemical methods, the structure and the presence of some major cell wall macromolecules in the intercellular pectic protuberances (IPPs) of the cortical parenchyma have been studied in a specimen of the Asplenium aethiopicum complex.

A sandwich-embedding method for oriented sectioning.

High-quality sections are indispensable for many scientific studies. Most published methods are often time-consuming or require special devices. We present an easy, quick and low-cost method for oriented embedding of thin structures using glycol methacrylate resin and self-constructed, reusable embedding tools made of overhead transparencies.

Phylogenetic analysis of Asplenium subgenus Ceterach (Pteridophyta: Aspleniaceae) based on plastid and nuclear ribosomal ITS DNA sequences.

Phylogenetic relationships among 20 taxa of the fern genus Asplenium subgenus Ceterach (Filicopsida, represented by 73 accessions) were investigated using DNA sequence data from the nuclear ribosomal internal transcribed spacers (ITS nDNA) and plastid trnL-F intergenic spacer. In addition, a single sample per taxon was used in an analysis of the plastid rbcL gene. Chromosome counts were determined for all the samples, and these demonstrated a range from diploid to octoploid.

Embedding thin plant specimens for oriented sectioning.

Small plant structures such as small primary roots, filamentous mosses and algae are difficult to orient for sectioning since they become wavy and curl during embedding. A method is described for embedding and orienting tiny plant specimens in a glycol methacrylate resin using self-constructed flat molds. Prior to sectioning, small samples can be oriented in both the longitudinal and the transverse plane.