Production of wheat starch based artificial endosperm by gel-sandwich technique and plantlet conservion from isolated zygotic embryos in pepper (Capsicum annum Lv. Feherozon).

Theoretically, the seed-analogue type artificial seed have to be considered as the third generation of the SYNSEED technology. According to this idea, therefore, it should be manufacture this type of artificial seeds with an appropriate artifiical endosperm, which consists of storable, enzymatically digestible and biologically active compounds, to copy the natural seeds. Meanyhile, in the literature of the SYNSEED technology the starch is a neglected compound, however, it is one of the most commonly spread form of storecompound of the endosperm in the seeds of Higher plant. Investigation were carried out in our laboratoy to deveoop appropriate experimental method for the wheat starch, as a potential row material for artificial endosperm. A new method, the "starch gel-sandwich artificial seed" have been established and investigated. Wheat starch based MS (1962) medium was prepared according to the method of Fari (1990), and it was poured into plastic Petri-dishes of 10 cm diameter to make two-millimetre ligh starch-medium layers. Modified pipette-tip was produced from a normal pipette of 100 capacity, which was cul-down at the end to make a cylinder of 8 mm diameter. Wheat starch medium-disks were obtained using this simple instrument with Finpipette. Followint the appropriate embryo-rescue method described by Fari et al. (1983), mature, 32-34 day-old, ring0-shape zygotic embryos of pepper (Capsicum annum L. cv. Feherozon) were isolated and placed onto the surface of the wheat starch medium-disks. After, a second disk was used to form a gel-sandwich structure, consisting one zygotic embryo of pepper and two gel-disks of wheat starch medium. The wsheat start gel-sandwich complexes were dehydrated following the procedure of PVC- foil desiccation method described by Fari et al. (1996), until 50%, 25% and 15% of water content, than they were rehydrated with distilled water. After two weeks, the ratio of germination were claculated and the plantlets were acclimatised and transferred to greenchouse. According to the 50%, 25% ant 15% sater content of the desiccatesd wheat starch gel-sandwiches artificial endosperm, the percentage of the gemination were 100%, 60% and 40%, respectively. The geminated plantlets geminated plantlets germinated well, produced flowers and normal seed set was recorded. On the basis of the "gel-sandwich method", out of whaeat starch, it is possible to test and produce a large scale enzymatically degradable compounds of artificial endosperm, without restriction the characters of chemo-hydrogels, used in the sodium alginate method

Associação de fases meióticas e estádios dos micrósporos com características morfológicas de botões florais de pimentão Association of meiotic phases and microspore stages with morphological characters of floral buds of pepper

Fases meióticas e estádios de micrósporos de pimentão (Capsicum annuum L. cv. Azeth) foram determinados e associados com características morfológicas adotadas para a seleção de botões florais a serem utilizados na indução de androgênese. Plantas foram mantidas em casa-de-vegetação para coleta dos botões florais, que foram separados em seis classes de acordo com a relação de tamanho entre cálice e corola e presença de pigmentos nas anteras. As anteras foram fixadas em metanol: ácido acético na proporção de 3:1 e armazenadas a -20º C. Preparações citogenéticas desse material foram montadas pela técnica de dissociação e secagem ao ar e coradas com solução de Giemsa. As observações dos botões foram realizadas sob lupa e as preparações citogenéticas em microscópio ótico. Imagens dos botões florais, das anteras e das fases meióticas foram digitalizadas em computador para documentação. Variações de fases meióticas dentro de cada classe de botão floral foram observadas. Embora o critério de presença de antocianina na extremidade das anteras tenha sido aplicado para outras variedades, o mesmo não se mostrou adequado para a determinação do estádio de micrósporo neste estudo. As fases meióticas foram citogeneticamente identificadas; contudo, não foi possível estabelecer sua associação com as classes dos botões florais. Entretanto, botões com o tamanho de cálice coincidindo com o da corola apresentaram maior número de micrósporos em estádio adequado para a cultura de anteras.<br>In the present study, morphological characters adopted for floral bud selection used for androgenesis induction were associated with pepper (Capsicum annuum L. cv. Azeth) meiotic phases and microspore stages. Floral buds were harvested from greenhouse-grown plants and separated into six classes according to size relationships between calyx and corolla, and anthocyanin pigmentation in anthers. After sorting by size, buds were fixed using a methanol: acetic acid (3:1) solution at -20ºC. Cytogenetic preparations were mounted using an adaptation of an air-drying technique and staining through a phosphate buffer Giemsa solution. Bud observations were accomplished under a stereo-microscope and the cytogenetic preparations in an optic microscope. Recordings of floral buds and meiotic phases were performed with an image digitizing computer system. Variations on the meiotic phases were observed within each class. Although the approach based on anthocyanin pigmentation on anthers has been applied to another pepper varieties, it was not a reliable trait for determination of the microspore stage. Meiotic phases were citogeneticaly identified, although bud stage could not be associated with it. On the other hand, buds having the same calyx and corolla sizes presented a larger number of microspores in a suitable stage for anther culture