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  • Author or Editor: Sung Do Oh x
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Immature cotyledons within nucleoulus of young fruits, 40-50 days old, were cultured on various media containing different concentrations of plant growth regulators. MS medium was most effective for callus formation, but cytokinins added to MS media containing 1.0 mg/l 2,4-D inhibited callus formation. Combination of 2,4-D and BAP was more effective than 2,4-D or BAP alone for somatic embryo formation from callus. Highest percent of somatic embryogenesis was observed on MS medium supplemented with 1.0mg/l 2,4-D and 50% sucrose. Cobalt and nickel, inhibitors of ethylene synthesis, reduced significantly the number of somatic embryos. Plantlets germinated freely from somatic embryos on MS medium containing 1.0mg/l zeatin and 0.01mg/1 2,4-D. Segments of hypocotyl, cotyledon and leaf blade were observed for callus formation, somatic enbryogenesis and plant regeneration. Shoots were directly differentiated from the callus induced from segments of hypocotyl on MS medium containing 0.1mg/l 2,4-D after 4 weeks of culture.

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Authors: and

Asparagine and arginine contents in spur buds, leaf buds and terminal buds of shoot were compared in Fuji and Jonagold apple trees during dormant and growing season. Amino acid contents in dormant spur buds were significantly higher in Jonagold than in Fuji, whereas the amino acid contents in shoot bark were not different in two cultivars. Asparagine and arginine contents were considerably higher in leaf and terminal buds of shoot. This phenomenon was quite obvious in Fuji than Jonagold but there was no significant difference in asparagine and arginine contents in spur buds. Flower buds differentiated on summer pruned shoots had higher contents of asparagine and arginine as compared with weak spur buds in Fuji but this was not quite obvious in Jonagold. It suggested that the irregular spur size and poor development of spur buds in Fuji cultivar might be caused by the poor translocation of amino acids as well as nitrogen compounds from shoots and other vegetative organs.

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Abstract

Water suspensions from seeds, root and shoots of peach (Prunus persica (L.) Batsch) influenced growth of peach, apple and bean seedlings when applied to soil of potted plants. Different levels of amygdalin were found in plant parts of peach and apple. Synthetic amygdalin applied to potted peach seedlings was not toxic. Certain nutrient elements were altered due to the soil treatment. Disposal of plant parts is suggested as a practical sanitation practice to possibly reduce peach tree decline on old soil.

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From one week through 7 weeks after artificial pollination, immature ovules of yooza(Citrus junos Sieb. et Tanaka) were excised and cultured in vitro on MT media. Even though there was only a little difference in percentage of somatic embryo formation depending upon the time of excision, immature ovules of 4-week-old showed the highest ratio of somatic embryo formation without callus outgrowth. Various growth regulators or other stimulators were added to the MT media to increase the somatic embryogenesis, In general, BAP was more effective than 2,4-D for somatic embryo formation and the combinations of 0.01mg/l 2,4-D and 0,01 or 0.1mg/l BAP were particularly effective in stimulating somatic embryo formation. When 500mg/l malt extract was added to the medium, the percentage of somatic embryo formation increased reaching as high as 86.7%. Plant regeneration from somatic embryos reached to 66.7% on the medium containing 1.0mg/l zeatin. Isozyme banding patterns were also analyzed to confirm the variations of characteristics of the plantlets derived from direct somatic embryos.

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