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β-N-acetylhexosaminidase was prepared from a liver lysosomal fraction obtained from rats between 18 days of gestation (group I) and 72 weeks of age (groups II-VI). A glycan chain analysis was performed after an electrophoresis and blotting, followed by a very sensitive detection system with highly specific digoxigenin-labelled lectins. The presence of high-mannose /hybrid type glycans, as well as their fucosylated forms was shown in all the experimental groups. Complex-type glycans with terminal sialic acid or galactose were present in all the groups except for 1-week-old rats in which only a positive reaction with lectins from Galanthus nivalis and Aleuria aurantia - was observed. Thus it may be assumed that age-related changes in the glycosylation pattern occur on the first days after birth.
In Poland Galanthus nivalis L. is partially protected. The flowers of this species are one of the first sources of nectar and pollen for insects from February to April. The aim of this study was to present the flowering biology as well as the topography, anatomical, and ultrastructural features of the floral nectary. The flower lifespan, the breeding system, and the mass of pollen and nectar produced by the flowers were determined. Examination of the nectary structure was performed using light, fluorescence, scanning and transmission electron microscopy. The flower of G. nivalis lives for about 30 days. The stamens and pistils mature simultaneously and during this time nectar is secreted. The anthers of one flower produced the large amount of pollen (4 mg). The breeding system of G. nivalis was found to be characterized by partial self-compatibility, outcrossing, and xenogamy. The nectary is located at the top of the inferior ovary. The nectary epidermal cells are characterized by striated cuticular ornamentation. Initially, the secreted nectar formed vesicle-like protuberances under the cuticle. The epidermal and parenchymal cells contain numerous plastids, mitochondria, dictyosomes, ER cisterns, and vesicles fused with the plasmalemma, which indicates granulocrine nectar secretion.
The structure of the flowers of Galanthus nivalis shows adaptations to early spring flowering conditions as well as adaptations to entomogamy. The tepals produce colour marks and odorous substances. The aim of the present study was to determine the micromorphology and anatomy of tepals, in particular in the regions comprising colour marks which, in accordance with the literature data, emit essential oils. Examination was performed using light, fluorescence, and scanning electron microscopy. Large protrusions, corresponding to the location of the green stripes, were found to occur on the adaxial surface of the inner tepals. The epidermal cells in this part of the tepals produce a cuticle with characteristic ornamentation as well as numerous stomata with well-developed outer cuticular ledges. The wide opening of many stomata is evidence of high activity in this area. The fluorescence microscopy images confirm the high activity of the epidermis (scent emission), on both sides of the tepals, as well as of the chloroplast- containing mesophyll. In the abaxial epidermis, there were observed different-sized papillae that also participated in essential oil secretion. The polarization of the epidermal cell protoplasts, large cell nuclei, and the presence of large vacuoles with heterogeneous contents in the peripheral part of the cells correspond to the structural features of the tissues emitting odorous compounds in flowers – osmophores. In freshly opened flowers, the mesophyll of the central part of the perianth segments was composed of several cell layers, whereas in older flowers large air ducts formed, which are adaptations to environmental thermal conditions.
Arabinogalactan proteins (AGPs) are a diverse class of highly glycosylated plant cell surface proteoglycans. They are discussed as signal molecules participating in cell-cell interaction or cellular signalling during morphogenetic processes. AGPs are abundant in the stigma and transmitting tissue of different flowering plants, and are supposed to play an important role in pollen tube adhesion and guidance. In the present work we localized two epitopes of AGPs using the monoclonal antibody JIM 8 and JIM 13 in ovules of anatomically different types. Although some differences in the localization of these epitopes in different plant species were observed, in all the studied ovules they were present on the pathway of pollen tube growth. In particular plant species they appeared at the time of the ovule’s highest receptivity.
In Galanthus nivalis during the progamic phase, both the embryo sac and somatic cells of the ovule change their ultrastructure and physiology, as observed by light, fluorescence, and electron microscopy. Fresh ovules from buds, opening flowers, and from cross-pollinated flowers were stained in toto to detect pectins, acidic polysaccharides, proteins, lipids, callose, free calcium ions and membrane-bound calcium. These substances were found only in the micropylar part of fertile ovules. All stainings were negative in sterile ovules. In EM, the somatic cells in the micropylar part of the ovule were observed to develop secretion activity. Their exudates passed to the intercellular spaces, mainly to the micropylar canal. The amount of the exudate increased after pollination. Free or loosely bound calcium ions were present in extracellular regions of the micropylar part of fertile ovules. The substances detected in the micropylar exudate of fertile ovules are suggested to support and direct pollen tube growth to the embryo sac.
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