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Ravindar Kaur-Sawhney Philip B. Applewhite Arthur W. Galston 《Plant Growth Regulation》1996,18(3):191-199
Thin longitudinal sections cut from pedicels of fifteen cultivars of tomato (Lycopersicon esculentum) were grown in vitro on Murashige-Skoog medium supplemented with various concentrations of different auxins and cytokinins. Isatin (an auxin precursor slowly converted to an active auxin) was the most effective source of auxin for the formation of buds without prior root formation, while zeatin was the most effective cytokinin for growth and development of the buds. Flower buds and ripe fruits developed consistently from explants of the cultivar Pixie Hybrid II treated with 10 M isatin plus 3 M zeatin as the cytokinin. Fruits developed parthenocarpically, grew to a diameter of about 15 mm, ripened promptly, and possessed normal color and flavor.Abbreviations BAP
benzylaminopurine
- IAA
indole-3-acetic acid
- IBA
indole-3-butyric acid
- IPA
isopentyladenosine
- NAA
-napthaleneacetic acid 相似文献
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We have developed a protocol for the in vitro propagation of the genus Clivia. Shoots were regenerated when fragments of the peduncle-pedicel junction (PP junction) from young inflorescences were used as explants. The optimal media for PP junction were Murashige and Skoog (MS)-based medium containing 10 M of 6-benzyladenine (BA) and 10 M of 2,4-dichlorophenoxyacetic acid (2,4-D) or MS supplemented with 5 M BA, 10 M -naphthaleneacetic acid (NAA), 250 mg l-1 glutamine and 500 mg l–1 casein hydrolysate and their usage depended on the breeding lines. Multiplication from initiations and in vitro seedlings was the best when the explants were cut longitudinally through the meristem and placed on MS plus 44 M BA. Plantlets were transferred on to hormone -free MS medium with charcoal for rooting. 相似文献
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The distribution of hydraulic resistances in xylem throughout the pathway leading to the tomato fruit was investigated. Previous work had indicated that there were large resistances within the supporting sections of this pathway (the peduncle and pedicel), perhaps associated with interruptions in the xylem. These high resistances are believed to impede calcium flux into the fruit and thus impair fruit development. It is shown here that fruit on intact plants do not shrink detectably during drought, even when the drought is sufficient to cause marked shrinkage of leaves and visible wilting of the shoot. In explants, it is possible to induce back‐flow from the fruit into the stem (probably via the xylem) but this flow is small and very slow. These observations support the view that there is a large hydraulic resistance in the pathway between fruit and stem. When pulses of water were made available within explants, by scorching of one leaflet, there was a rapid swelling of leaves and sepals. Such rapid fluxes indicate the presence of strong hydraulic (xylem) connections throughout the pathway between leaf and calyx. This shows that there are no significant hydraulic constrictions in the xylem proximal to the calyx. This finding is contrary to some previous conclusions but it is supported by experiments with dyes which showed continuous, functional xylem throughout the peduncle and pedicel. Calculations show that over 90% of the hydraulic resistance between stem and fruit must reside within the fruit pericarp. Implications for calcium nutrition are discussed. 相似文献
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Most nonmammalian species replace their teeth continuously (so-called polyphyodonty), which allows morphological and structural modifications to occur during ontogeny. We have chosen Pleurodeles waltl, a salamander easy to rear in the laboratory, as a model species to establish the morphological foundations necessary for future molecular approaches aiming to understand not only molecular processes involved in tooth development and replacement, but also their changes, notably during metamorphosis, that might usefully inform studies of modifications of tooth morphology during evolution. In order to determine when (in which developmental stage) and how (progressively or suddenly) tooth modifications take place during ontogeny, we concentrated our observations on a single tooth family, located at position I, closest to the symphysis on the left lower jaw. We monitored the development and replacement of the six first teeth in a large growth series ranging from 10-day-old embryos (tooth I1) to adult specimens (tooth I6), using light (LM), scanning (SEM), and transmission electron (TEM) microscopy. A timetable of the developmental and functional period is provided for the six teeth, and tooth development is compared in larvae and young adults. In P. waltl the first functional tooth is not replaced when the second generation tooth forms, in contrast to what occurs for the later generation teeth, leading to the presence of two functional teeth in a single position during the first 2 months of life. Larval tooth I1 shows dramatically different features when compared to adult tooth I6: a dividing zone has appeared between the dentin cone and the pedicel; the pulp cavity has enlarged, allowing accommodation of large blood vessels; the odontoblasts are well organized along the dentin surface; tubules have appeared in the dentin; and teeth have become bicuspidate. Most of these modifications take place progressively from one tooth generation to the next, but the change from monocuspid to bicuspid tooth occurs during the tooth I3 to tooth I4 transition at metamorphosis. 相似文献
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应用正交试验设计法研究基本培养基、植物生长调节剂种类及浓度对文心兰花梗茎段芽再生丛生芽诱导、增殖和生根培养的影响。筛选出最佳基本培养基为1/2 MS;最佳诱导培养基为1/2 MS+6-BA 5.0 mg/L+NAA 0.5 mg/L+蔗糖20 g/L;最佳增殖培养基为1/2 MS+6-BA 3.0 mg/L+NAA 0.5 mg/L+蔗糖30 g/L;最佳生根培养基为1/2 MS+IBA 0.05 mg/L+NAA 0.3 mg/L+香蕉泥100 g/L+蔗糖20 g/L。 相似文献
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Sicyopterus japonicus (Teleostei, Gobiidae), a hill‐stream herbivorous gobiid fish, possesses an unusual oral dentition among teleost fishes on account of its feeding habitat. By using scanning electron microscopy, light microscopy, and transmission electron microscopy, including vital staining with tetracycline, we examined the development of the attachment tissues of the upper jaw teeth in this fish. The functional teeth of S. japonicus had an asymmetrical dentine shaft. The dentine shaft attached to the underlying uniquely shaped pedicel by means of two different attachment mechanisms. At the lingual base, collagen fiber bundles connected the dentine shaft with the pedicel (hinged attachment), whereas the labial base articulated with an oval‐shaped projection of the pedicel (articulate attachment). The pedicel bases were firmly ankylosed to the crest of the thin flange of porous spongy bone on the premaxillary bone, which afforded a flange‐groove system on the labial surface of the premaxillary bone. Developmentally, the pedicel and thin flange of spongy bone were completely different mineralized attachment tissues. The pedicel had a dual origin, i.e., the dental papilla cells, which differentiated into odontoblasts that constructed the internal surface of the pedicel, and the mesenchymal cells, which differentiated into osteoblasts that formed the outer face of the pedicel. A thin flange of spongy bone was deposited on the superficial resorbed labial side of the premaxillary bone proper, and later rapid bone remodeling proceeded toward the pedicel base. These unique features of pedicellate tooth attachment for the upper jaw teeth in the adult S. japonicus are highly modified teeth for enhancing the ability of individual functional teeth to move closely over irregularities in the rock surfaces during the scraping of algae. J. Morphol., 2013. © 2012 Wiley Periodicals, Inc. 相似文献
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