I started feeling all those negative things so I walked around with no teeth in my mouth, not because I wanted to but because of being penniless.
For Permissions, please email: Asymbiotic germination provides a useful way to re-establish plants in the wild and for commercial propagation. A detailed study of embryo development would provide information on subsequent germination events and aid in the propagation of the species.
During the early globular stage of embryo development, structural differentiation occurs, revealing an abundance of smooth endoplasmic reticulum cisternae and wall ingrowths within the suspensor cells.
These features are not present in cells of the embryo proper.
Furthermore, the results of Nile red staining demonstrate that a cuticular layer is present only in the embryo proper, but absent from the suspensor. Cuticular material is also present in the inner walls of the seed coat, and persists through seed maturation. The absence of an endosperm and presence of cuticular material in the inner walls of the seed coat enclosing the embryo proper further support the notion that nutrient uptake by the embryo is confined to the micropylar end of the seed through the suspensor.
One of the distinctive features of orchid embryos is the diverse morphology of their suspensors. InSwamy devised a classification scheme for orchid embryo development based on suspensor morphology alone. Depending on the species, the suspensor of orchids may be unicellular or else consist of a few filamentous cells Swamy, ; Clements, At the light microscope level, the orchid suspensor usually appears as a vacuolated organ such as found in Phaius Ye et al.
The suspensor in flowering plants is important to embryo development. Structural and experimental evidence clearly indicates that it can serve as a conduit for nutrient flow and may provide unique metabolites for the growth of the embryo proper Yeung and Meinke, ; Nikitcheva, ; Yeung et al.
Endoplasmic reticulum ER cisternae and specialized plastids can also be abundant within the cytoplasm of suspensor cells.
At present, detailed ultrastructural information concerning orchid suspensors is lacking see Yam et al. Owing to the vacuolated nature of the orchid suspensor cells, it is uncertain whether these cells indeed have structural specializations similar to those of other flowering plants. Thus, in order to support the notion that the orchid suspensor serves as the conduit for nutrient flow to the embryo proper, additional structural information is needed.
The genus Paphiopedilum comprises a number of commercially important species that have been extensively cultivated and produce a wide range of attractive varieties, cultivars or hybrids as a result of intensive breeding Cribb, It is of interest horticulturally, but is also considered to be a threatened species in the wild due to over-collection and habitat destruction.
Similar to many terrestrial orchids, Paphiopedilum seeds are very difficult to germinate in vitro Pierik et al. For the conservation and commercial production of this endangered species, information concerning its reproductive biology and improved methods of in vitro propagation are thus of great importance.
Basic knowledge of embryo and seed development will aid in the design of experiments for asymbiotic seed germination studies, as shown in our previous study of Cypripedium formosanum Lee et al.
At present, information concerning embryo development in Paphiopedilum species is limited, except for work on P. In this study, the structural pattern of embryo development of P. In addition, emphasis was placed on the ultrastructural features of the suspensor to determine whether the suspensor indeed has the structural requirements to serve as a nutrient conduit for the developing embryo.
Anthesis occurs during March—April. To ensure a good fruit set and seed quantity, flowers were hand-pollinated. Developing fruits were harvested at regular intervals after pollination.
Approximately 40 developing fruits were gathered for this study. At each developmental stage, more than embryos were analysed under light microscopy to examine their morphological characteristics.TriMet provides bus, light rail and commuter rail transit services in the Portland, Oregon, metro area.
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Read an interview with David and learn about his experience participating in a Write Around Portland workshop. Workshops We hold free creative writing workshops in hospitals, shelters, senior centers, prisons, schools and treatment facilities. Priority registration given to individuals who have not previously participated in a Write Around Portland workshop.
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