Floral morphological and chemical analyses of Dienia flowers (Orchidaceae, Malaxidinae) relative to pollination processes.

Dienia is a small, pantropical genus of epidendroid Malaxideae orchids. The floral lip is upwardly directed and does not serve as a landing platform for pollinators. This role has been assumed by sepals and/or gynostemium or whole inflorescence.

Callose deposition analysis with special emphasis on plasmodesmata ultrastructure during megasporogenesis in Sedum (Crassulaceae).

In this study, the results of the first detection of callose within the ovules of the representatives of the family Crassulaceae are presented. This study was carried out on three species of the genus Sedum. Data analysis showed differences in the callose deposition pattern between Sedum hispanicum and Sedum ser.

[Embryogenesis in Crassulaceae: structural aspect of suspensor development].

The suspensor in the majority of angiosperms is an evolutionally conserved embryonic organ functioning as a conduit that connects ovule tissues with the embryo proper for nutrients and growth regulators flux. In this article the present knowledge on the embryo-suspensor ultrastructure and function in representatives of Crassulaceae genera: Sedum, Jovibarba, Sempervivum, Aeonium, Monanthes, Aichryson and Echeveria. The role of the suspensor in the transport of nutrients from the tissues of the ovule to the proper embryo is confirmed by the structure of the basal cell, especially the nature of the micropylar part of its wall, the "transfer wall".

sect. (Orchidaceae, Malaxidinae)-Chemical and Morphological Study of Flower Structures in the Context of Pollination Processes.

is a large genus of mainly pantropical orchids. The lips of its flowers are upwardly directed and do not serve as landing platforms for pollinators. This role is assumed by the dorsal sepal and/or gynostemium.

Protuberances are organized distinct regions of long-term callus: histological and transcriptomic analyses in kiwifruit.

Macroscopic, ultrastructural, and molecular features-like a ball shape, the presence of starch granules, and the up-regulation of genes involved in carbohydrate metabolism and secondary metabolite biosynthesis-distinguish PT regions within a callus. The modification of the mass of pluripotent cells into de novo shoot bud regeneration is highly relevant to developmental biology and for agriculture and biotechnology. This study deals with protuberances (PT), structures that appear during the organogenic long-term culturing of callus (OC) in kiwifruit.

Developmental, ultrastructural and cytochemical investigations of the female gametophyte in Sedum rupestre L. (Crassulaceae).

This article describes the development of female gametophyte in Sedum rupestre L. New embryological information about the processes of megasporogenesis and megagametogenesis provided in this paper expand the current knowledge about the embryology of the studied species. S.

Development of Embryo Suspensors for Five Genera of Crassulaceae with Special Emphasis on Plasmodesmata Distribution and Ultrastructure.

The suspensor in the majority of angiosperms is an evolutionally conserved embryonic structure functioning as a conduit that connects ovule tissues with the embryo proper for nutrients and growth factors flux. This is the first study serving the purpose of investigating the correlation between suspensor types and plasmodesmata (PD), by the ultrastructure of this organ in respect of its full development. The special attention is paid to PD in representatives of Crassulaceae genera: , , , and .

The effect of vanadium(IV) complexes on development of Arabidopsis thaliana subjected to HO-induced stress.

The impact of oxydiacetate oxidovanadium(IV) complexes on plants is currently unknown. This report demonstrates the influence of these complexes on Arabidopsis thaliana (L.) Heynh.

Female gametophyte development in Sedum sediforme (Jacq.) Pau (Crassulaceae): an anatomical, cytochemical and ultrastructural analysis.

Available documentation about the development of the female gametophyte of Crassulaceae is very limited. The aim of this study was to extend the embryological knowledge of Crassulaceae by analysing the development of the embryo sac in Sedum sediforme. Transmission electron microscopy and light microscopy including Nomarski optics (DIC) were used to observe individual stages of female gametophyte development.

Establishing the cell biology of apomictic reproduction in diploid Boechera stricta (Brassicaceae).

Background And Aims: In the Brassicaceae family, apomictic development is characteristic of the genus Boechera. Hybridization, polyploidy and environmental adaptation that arose during the evolution of Boechera may serve as (epi)genetic regulators of apomictic initiation in this genus. Here we focus on Boechera stricta, a predominantly diploid species that reproduces sexually.

Floral features of two species of Bulbophyllum section Lepidorhiza Schltr.: B. levanae Ames and B. nymphopolitanum Kraenzl. (Bulbophyllinae Schltr., Orchidaceae).

Two representatives of section Lepidorhiza, previously sometimes considered conspecific, Bulbophyllum levanae and Bulbophyllum nymphopolitanum, demonstrated both similarities and differences in floral features. There were significant differences in the length of sepals and micromorphological features of the labellum. In both species, osmophores are located on the extended apices of sepals and possibly on petals.

Ultrastructural and cytochemical aspects of female gametophyte development in Sedum hispanicum L. (Crassulaceae).

Until now, development of the female gametophyte has been investigated only in some species of Crassulaceae using a light microscope. To the best of our knowledge, this is the first report that describes the process of megasporogenesis and megagametogenesis in Crassulaceae in detail. To achieve this, we performed embryological studies on Sedum hispanicum L.

Integument cell gelatinisation-the fate of the integumentary cells in Hieracium and Pilosella (Asteraceae).

Members of the genera Hieracium and Pilosella are model plants that are used to study the mechanisms of apomixis. In order to have a proper understanding of apomixis, knowledge about the relationship between the maternal tissue and the gametophyte is needed. In the genus Pilosella, previous authors have described the specific process of the "liquefaction" of the integument cells that surround the embryo sac.

Identification of symplasmic domains in the embryo and seed of Sedum acre L. (Crassulaceae).

Our study demonstrated that symplasmic communication between Sedum acre seed compartments and the embryo proper is not uniform. The presence of plasmodesmata (PD) constitutes the structural basis for information exchange between cells, and symplasmic communication is involved in the regulation of cell differentiation and plant development. Most recent studies concerning an analysis of symplasmic communication between seed compartments and the embryo have been predominantly performed on Arabidopsis thaliana.

Floral structure of two species of Bulbophyllum section Cirrhopetalum Lindl.: B. weberi Ames and B. cumingii (Lindl.) Rchb. f. (Bulbophyllinae Schltr., Orchidaceae).

Flowers of Bulbophyllum weberi and B. cumingii are characterized by fly-pollinated features. The secretory activity was described in dorsal sepals in both species (putative osmophores), petals in B.

A Different Pattern of Production and Scavenging of Reactive Oxygen Species in Halophytic Eutrema salsugineum (Thellungiella salsuginea) Plants in Comparison to Arabidopsis thaliana and Its Relation to Salt Stress Signaling.

Isolated thylakoids from halophytic Eutrema salsugineum (Thellungiella salsuginea) produces more H2O2 in comparison to glycophytic Arabidopsis thaliana. The first objective of this study was to verify whether this feature is relevant also to the intact chloroplasts and leaves. Enhanced H2O2 levels in chloroplasts and leaves of E.

Are obligatory apomicts invested in the pollen tube transmitting tissue? Comparison of the micropyle ultrastructure between sexual and apomictic dandelions (Asteraceae, Lactuceae).

With the exception of the sunflower, little information concerning the micropyle ultrastructure of the family Asteraceae is available. The aim of our study was to compare the micropyle structure in amphimictic and apomictic dandelions. Ultrastructural studies using buds and flowers during anthesis have been done on the micropyle of the sexual and apomictic Taraxacum.

The localization of NADPH oxidase and reactive oxygen species in in vitro-cultured Mesembryanthemum crystallinum L. hypocotyls discloses their differing roles in rhizogenesis.

This work demonstrated how reactive oxygen species (ROS) are involved in the regulation of rhizogenesis from hypocotyls of Mesembryanthemum crystallinum L. cultured on a medium containing 1-naphthaleneacetic acid (NAA). The increase of NADPH oxidase activity was correlated with an increase of hydrogen peroxide (H2O2) content and induction of mitotic activity in vascular cylinder cells, leading to root formation from cultured hypocotyls.

Cytochemical and ultrastructural aspects of aquatic carnivorous plant turions.

Turions, which are modified shoot apices, are vegetative, dormant overwintering organs produced by perennial aquatic plants. In this study, the turion cytochemistry and ultrastructure of Aldrovanda vesiculosa, Utricularia vulgaris and U. stygia were compared with particular emphasis placed on storage substances.

Rhinanthus serotinus (Schönheit) Oborny (Scrophulariaceae): immunohistochemical and ultrastructural studies of endosperm chalazal haustorium development.

Chalazal endosperm haustorium in Rhinanthus serotinus consists of a single large binucleate cell. It originates from the primary endosperm cell dividing transversely into two unequal cells: a smaller micropylar cell and a larger chalazal cell. The chalazal cell undergoes a single mitotic division, then lengthens significantly during development and functions as a chalazal endosperm haustorium.

Organisation of the endosperm and endosperm-placenta syncytia in bladderworts (Utricularia, Lentibulariaceae) with emphasis on the microtubule arrangement.

Multinucleate cells play an important role in higher plants, especially during reproduction; however, the configurations of their cytoskeletons, which are formed as a result of mitosis without cytokinesis, have mainly been studied in coenocytes. Previous authors have proposed that in spite of their developmental origin (cell fusion or mitosis without cytokinesis), in multinucleate plant cells, radiating microtubules determine the regular spacing of individual nuclei. However, with the exception of specific syncytia induced by parasitic nematodes, there is no information about the microtubular cytoskeleton in plant heterokaryotic syncytia, i.

Genotype-dependent efficiency of endosperm development in culture of selected cereals: histological and ultrastructural studies.

The paper reports studies, including histological and ultrastructural analyses, of in vitro cell proliferation and development of immature endosperm tissue isolated from caryopses of Triticum aestivum, Triticum durum, and Triticosecale plants. Endosperm isolated at 7-10 days post-anthesis developed well on MS medium supplemented with auxins and/or cytokinins. The efficiency of endosperm response was highly genotype-dependent and best in two winter cultivars of hexaploid species.

Are there symplastic connections between the endosperm and embryo in some angiosperms?--a lesson from the Crassulaceae family.

It is believed that there is symplastic isolation between the embryo (new sporophyte) and the endosperm (maternal-parental origin tissue, which nourishes the embryo) in angiosperms. However, in embryological literature there are rare examples in which plasmodesmata between the embryo suspensor and endosperm cells have been recorded (three species from Fabaceae). This study was undertaken in order to test the hypothesis that plasmodesmata between the embryo suspensor and the endosperm are not so rare but also occur in other angiosperm families; in order to check this, we used the Crassulaceae family because embryogenesis in Crassulaceae has been studied extensively at an ultrastructure level recently and also we tread members of this family as model for suspensor physiology and function studies.

Cutin plays a role in differentiation of endosperm-derived callus of kiwifruit.

Cutin fluorescence, after auramine O treatment, was detected on the surface of organogenic areas (protuberances) of endosperm derived callus induced on Murashige and Skoog medium with thidiazuron (0.5 mg l(-1)) in darkness. Electron micrographs of the protuberances revealed cuticle, visible as a dark-staining layer, and amorphous waxes on the cell wall.

New data about the suspensor of succulent angiosperms: Ultrastructure and cytochemical study of the embryo-suspensor of Sempervivum arachnoideum L. and Jovibarba sobolifera (Sims) Opiz.

The development of the suspensor in two species - Sempervivum arachnoideum and Jovibarba sobolifera - was investigated using cytochemical methods, light and electron microscopy. Cytological processes of differentiation in the embryo-suspensor were compared with the development of embryo-proper. The mature differentiated suspensor consists of a large basal cell and three to four chalazal cells.