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  • Author or Editor: Hyun-Ju Kim x
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Germanium has been reported as a mineral element affecting plant cell metabolism. Many trials to supply germanium to fruit have been carried out since tests have confirmed germanium's role as a medical substance. Supplying germanium to orchards by soil and foliar application was not effective because of loss from rainfall. Also, tree injection with germanium solution required the insertion of a tube to the tree xylem at each injection site. In order to increase germanium absorption by fruit, this study carried out the postharvest dipping of fruit into germanium solution. `Niitaka' pear (Pyruspyrifolia) fruit was treated with two types of germanium, GeO (inorganic type) and Ge-132 (organic type), in a concentration of 50 mg·L–1 just after harvest in early Oct. 2004. Flesh browning after peeling the fruit was delayed by germanium treatment, and polyphenoloxidase (PPO) activities were lowered. Postharvest potentials were maintained at high levels for fruit firmness, physiological disorders, and decayed fruit during cold storage at 0 to 1 °C for 2 months. Antioxidant and some phenolic compounds were higher than those of control fruit.

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Cucumber green mottle mosaic virus (CGMMV) is a noxious disease in cucurbits, especially in Asia where grafting is commonly practiced. CGMMV can be easily transmitted by seed, hands, soil, or grafting. Seed companies are rigorously looking for effective and efficient means of CGMMV inactivation in infected seeds. Among the various treatments applied to the seeds, dry heat treatment (35° C 1 day + 50 °C 1 day + 75 °C 3 days) was found to be most suitable for complete inactivation. Various identification methods including high-density latex agglutination test (HDLPAT), ELISA, RT-PCR, and bioassay (Chenopodium amaranticolor) were compared for accurate diagnosis of the presence of virus in seeds. The results from HDLPAT showed the highest correlation with the bioassay results, suggesting that HDLPAT can be safely used for accurate means of virus detection. Details of dry heat treatment, various seed treatment, and other detection methods will be presented.

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Traditionally fatty acid composition used to be analysed by GC and the sample preparation consisted of lipid extraction from sample and subsequent methyl esters preparation, which are time-consuming and cumbersome. As an alternative, simultaneous extraction/methylation methods are being developed for rapid and simplified sample preparation. To optimize one-step extraction/methylation method for analysis of fatty acid composition in brown rice and adlay seeds, various factors, such as sample to reaction solution ratio, reaction time and temperature, and shaking intensity, were altered and resultant fatty acid composition data were evaluated in comparison with previous reports. The ratio of sample weight to reaction solution volume was the most critical factor in that higher sample to reaction solution ratio caused overestimation of palmitic acid and linoleic acid composition, resulting in underestimation of oleic acid. Lower reaction temperature also induced overestimation of linoleic acid and underestimation of oleic acid. Reaction duration and the intensity of shaking prior to and during the reaction, however, induced no significant changes in analysis results. In conclusion, the optimum condition for brown rice was mixing 5 grains (about 0.2 g) of brown rice with 680 μL of methylating mixture and 400 μL of heptane, followed by reaction at 80 °C for 2 hours.

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The shells of crab, shrimp, beetles, etc., could be decomposed by chitinase to chitin, calcium, and protein, respectively. We incubated the mixture solution of 1.5 kg crab shell, 1.5 kg multinutrient, 2 kg compost with microorganisms to decompose the chitin substance, 3 kg sugar, and 700 L water at room temperature for 7 days. During the incubation, aeration with an air pump was essential. We sprayed the chitin-incubated solution (CIS) after filtering to `Niitaka' pear (Pyrus pyrifolia) trees at 15-day intervals from May to Sept. 2004. Leaf area, leaf thickness, leaf specific weight, and chlorophyll contents were increased by the treatment with CIS. In fruit characteristics, fruit weight, soluble solids, fruit firmness, and Hunter values “a” and “b”were increased by the CIS treatment. Flesh browning after peeling the fruit was delayed by the CIS treatment, and polyphenoloxidase (PPO) activities were lowered.

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Fatty acid is known as a physiologically active compound, and its composition in rice may affect human health in countries where rice is the major diet. The fatty acid composition in brown rice of 120 Korean native cultivars was determined by one-step extraction/methylation method and GC. The average composition of 9 detectable fatty acids in tested rice cultivars were as followings: myristic acid; 0.6%, palmitic acid; 21.2%, stearic acid; 1.8%, oleic acid; 36.5%, linoleic acid; 36.3%, linolenic acid; 1.7%, arachidic acid; 0.5%, behenic acid; 0.4%, and lignoceric acid; 0.9%. Major fatty acids were palmitic, oleic and linoleic acid, which composed around 94%. The rice cultivar with the highest linolenic acid was cv. Jonajo (2.1%), and cvs. Pochoenjangmebye and Sandudo showed the highest composition of palmitic (23.4%) and oleic acid (44.8%), respectively. Cultivar Pochuenjangmebye exhitibed the highest composition of saturated fatty acid (28.1%), while cvs. Sandudo and Modo showed the highest mono-unsaturated (44.8%) and poly-unsaturated (42.4%) fatty acid composition, respectively. The oleic acid showed negative correlation with palmitic and linoleic acid, while positive correlation between behenic and lignoceric acids was observed.

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Lilium lancifolium (syn. L. tigrinum) is the only polyploidy-complex species involving both diploid (2n = 2x = 24) and triploid (2n = 3x = 36) plants in the genus. The origin of natural triploid remains a mystery and research has been limited mainly to chromosomal studies that have overlooked research on pollen ontogeny. By spatiotemporal comparison of the development and morphology of diploid and triploid pollen grains, we study the correlations between pollen fertility and morphological development in diploid and triploid plants and propose the necessity and importance of further research on natural polyploid-ontogenetic diversity. In this comparative investigation, we used various microscopy techniques including histological analyses, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The main morphological differences between triploid and diploid pollen grains started with abnormal tetrad formation of triploid, followed by inadequate amylogenesis and amylolysis in young microspores, and finished with the formation of an abnormal structure of pollen surface layers in maturing pollen grains, which finally resulted in pollen grain unfolding and male sterility. From observing the series of morphological events that induced male-sterile pathway in natural triploid pollens, this study showed a variety of correlations between pollen development and fertility, which differed from male sterility resulting from gene mutation, indicating that there exists greater variability in pollen male-sterile ontogeny. Our results suggest that multilateral research is required for understanding the fickle ontogeny of natural male-sterile polyploid.

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