• Korean journal of applied entomology
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• v.14 no.4 s.25
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• pp.193-198
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• 1975

This experiment was performed to clarify the concentration of rice stripe virus in the rice Plant leaves by serological test, and was attempted to inspect the virus carrier among small brown planthopper by antibody-sensitized hemagglutination test. The antiserum was prepared by injecting intervenously into the external marginal vein of the ear of a rabbit. The precipitin titer of it was 1 : 16. The rough virus fluid prepared from diseased leaves was centrifuged at 10.000 rpm, and then the supernatant solution was treated at $55^{\circ}C$ for 5 minutes and the solution clarified by removing the agglutinate was used as the antigen solution. Antibody-sensitized erythrocyte solution was prepared from sheep erythrocytes sensitized by rice stripe virus with tannic acid, and its agglutination titer was 1 : 512. The virus concentrations in flag leaves or first leaves just below them showing different symptoms was high with progressing the severity of symptoms. And the concentrations of the virus in leaves of varieties of the rice plant showing same degree symptom were lower in suscetible varieties, Sadominori, Palgoeng, Mangyong and Nihonbare, than in the resistant one, Tongil, but in Yooshin which was known as the resistant, lower rather than in Tongil. The reacton of antibody-sensitized hemagglutination test to inspect the virus carrier, was so highly sensitive that this reaction was recognized as a method which is able to Identify the carrier accurately in short time.

• Journal of Sericultural and Entomological Science
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• v.43 no.1
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• pp.21-25
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• 2001

Jeung-pyun added to mulberry leaves powder was tested to prove in inorganic ingredients, physical function, chromaticity and rheometer. For cake, mulberry leaves powder were added to rice flour in the ratio of 0%, 1%, 2%, and 3% respectively. In inorganic ingredients test, the amounts of calcium, magnesium and potassium were increased according to adding levels of mulberry leaves powder. But the amounts of iron, copper and zinc, were not correlated with it. Calcium, magnesium and potassium are anti-hypertension inorganic substances. Thus, it is considered that food with plenty amountsz of inorganic ingredients is an effective diet for the patients who suffer from cardiovascular disease. In physical evalution test, the ratio of mulberry leaves powder was not correlated with the appearance of Jeung-pyun. The value of color decreased as the ratio of mulberry leaves powder increases. In texture, Jeung-pyun. The value of color decreased as the ratio of mulberry leaves power increase. In texture, Jeung-pyun added with 2% mulberry leaves powder had the highest value. In moisture, as the level of mulberry leaves powder was increased, the value was decreased. In rheometer test, Jeung-pyun 0% mulberry leaves powder had the highest value in hardness. While the ratio of mulberry leaves powder was not correlated with cohesiveness. Jeung-pyun added to 1% mulberry leaves powder had the highest value. In gummines and brittleness, 0% Jeung-pyun had the highest value, but the ratio was not correlate with cohesiveness.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.1
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• pp.54-61
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• 2002

The antioxidant activities of methanol extracts of sixteen samples were tested using 1.1-diphenyl-2-picryl hydrazyl(DPPH) reactivity and TBARS substances assay in vitro. The methanol extracts of the rice brans from three wild rice -O. minuta, O. rufipogon, and O. barthii-were found to be the most effective in DPPH radical scavenging activity. The next effective ones were the rice brans of Heugjinjubyeo and leaves of Tapgolbori. When tested on lipid peroxidation using a lipid peroxidation generation system mediated by $H_2O$$_2$/Fe$^{2+}$ in rat liver homogenates, the brans and hull of wild rice (O. minuta, O. rufipogon, and O. barthii) and rice bran of Heugjinjubyeo exhibited protective activities against lipid peroxidation in the order of effectiveness.s.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.187-187
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• 2017

Cadmium (Cd) pollution is rapidly increasing in worldwide due to industrialization and urbanization. In addition to its negative effects on the environment, Cd pollution adversely affects human health. Rice (Oryza sativa L.) is an important agricultural crop worldwide, including South Korea, and studies have examined its ability to alleviate Cd uptake from the soil into plants. However, information about the relationship between sulfur (S) and antioxidants in rice seedlings is still limited with regard to Cd phytotoxicity. We therefore investigated the changes in reactive oxygen species (ROS) and antioxidants in rice (Oryza sativa L. 'Dongjin') seedlings exposed to toxic Cd, S treatment, or both. The exposure of rice seedlings to $30{\mu}M$ Cd inhibited plant growth; increased the contents of superoxide, hydrogen peroxide, and malondialdehyde (MDA); and induced Cd uptake by the roots, stems, and leaves. Application of S to Cd-stressed seedlings decreased Cd-induced oxidative stress by increasing the capacity of the glutathione (GSH)-ascorbate (AsA) cycle, promoted S assimilation by increasing cysteine, GSH, and AsA contents in treated plants, and decreased Cd transfer from the roots to the stems and leaves. In conclusion, S application of plants under Cd stress promoted Cys and GSH biosynthesis and GSH-AsA cycle activity, thereby lowering the rate of Cd transfer to plant shoots and promoting the scavenging of the ROS that resulted from Cd toxicity, thus alleviating the overall Cd toxicity. Therefore, these results provide insights into the role of S in regulating the tolerance, uptake, and translocation of Cd in rice seedlings. The results of this study indicate that S application should have potential as a tool for mitigating Cd-stress in cereal crops, especially rice.

• Korean Journal Plant Pathology
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• v.1 no.3
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• pp.190-194
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• 1985

The insect vector (Laodelphax striatellus) of rice black-streaked dwarf virus prefered rice plant to maize in feeding both in the cage and in the field, whereas the percent of infectious plants was much higher in maize than rice plants. The causal virus reduced the adult longevity, total number of hatching nymphs and maturity rate from nymphs of the insect vector. The percent of dry weight over fresh weight in rice from early to late growth stages was lower in diseased plants than in healthy plants but it was reversed on maize plant in early growth stage. In agarose gel-diffusion and microprecipitin serological tests, the intensities of antigen with antisera were in orders the preparation partially purified from infected maize leaves> rice stems> rice leaves> maize stems. The pholem galls in diseased plants developed well in the low temperature.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.77-80
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• 2002

A simple method for sporangial formation of the rice downy mildew pathogen, Sclerophthora macrospora, on infected leaf tissues was developed to facilitate diagnosis of the disease. Freshly infected young leaves showing whitish to yellowish small spots were selected and cut into small pieces about 2-3 cm in length. About 10-20 pieces were surface sterilized in a 100 ml Duran bottle with 40 ml of 70% ethanol by vigorous shaking for 30 seconds. After washing three times with distilled water, the leaf cuts were submerged in 10 ml of Millipore-filtered paddy water and incubated at $20^{\circ}C$ in the dark. After 8-10 h of incubation, the bottle was vigorously agitated on a vortex mixer, Aliquot amount of the suspension, 0.1-1.0 m1, was spread on a slide glass and examined under a light microscope at 50 or 100x magnification. It was found that light and 1% NaClO strongly inhibit sporangial formation of S. macrospora. Meanwhile, the use of freshly infected young loaves and washing with 70% ethanol stimulated sporangial formation of the fungus on rice leaves.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.216-223
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• 2003

This study was conducted to investigate the varietal differences in leaf senescence and the relationship between leaf senescence and photosynthesis during ripening stage of rice. During grain filling period, leaf senescence was evaluated by SPAD readings (an indirect indicator of chlorophyll content) for 3 rice varieties (SNU-SG1, Hwaseongbyeo, Nampungbyeo). SPAD value of flag leaf and 2nd leaf of SNU-SG1 were much higher than the other varieties and the leaves of SNU-SG1 also showed a tendency of delayed senescence as compared to the other varieties. Photosynthesis at light saturation (Pmax) of flag, 2nd and 3rd leaf in SNU-SG1 during grain filling period were much higher than Hwaseongbyeo and Nampungbyeo. The Pmax of the flag leaf in SNU-SG1 was especially higher over 20% than the other varieties. It was due to its higher mesophyll conductance and stomatal conductance as compared to the other varieties. Pmax, stomatal conductance and mesophyll conductance had positive correlation with SPAD value and nitrogen concentration of leaves. In conclusion, the stay green characteristics of SNU-SG1 would contribute to increasing the grain yield through the improved photosynthesis during grain filling.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.257-263
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• 2000

Infection with rice blast fungus (Magnaporthe grisea) significantly reduced foliar net photosynthesis (A) of rice cultivars: Ilpoom, Hwasung, and Choochung in greenhouse experiments. By measuring the amount of diseased leaf area with a computer image analysis system, the relation between disease severity (DS) and net photosynthetic rate was curvilinearly correlated (r=0.679). Diseased leaves with 35% blast symptom can be predicted to have a 50% reduction of photosynthesis. The disease severity was linearly correlated (r=0.478) with total chlorophyll (chlorophyll a and chlorophyll b) per unit leaf area(TC). Light use efficiency was reduced by the fungal infection according to the light response curves. However, dark respiration (Rd) did not change after the fungal infection (p=0.526). Since the percent of reduction in photosynthesis greatly exceeded the percent of leaf area covered by blast lesions, loss of photosynthetic tissue on an area basis could not by itself account for the reduced photosynthesis. Quantitative photosynthetic reduction can be partially explained by decreasing TC, but cannot be explained by decreasing Rd. By photosynthesis (A)-internal CO$_2$ concentration (C$_i$ curve analysis, it was suggested that the fungal infection reduced ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, ribulose-1,5-bisphosphate (RuBP) regeneration, and inorganic phosphate regeneration. Thus, the reduction of photosynthesis by blast infection was associated with decreased TC and biochemical capacity, which comprises all carbon metabolism after CO$_2$ enters through the stomata.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.10a
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• pp.15-20
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• 2005

Locations of silicon accumulation in rice leaves and its possible association with resistance to rice blast were investigated by analytical electron microscopy and atomic force microscopy. A blast-susceptible cultivar, Jinmi, and partially resistant cultivars, Hwaseong and Suwon345, were grown under a hydroponic culture system with modified Yoshida's nutrient solution. Electron-dense silicon layers were frequently found beneath the cuticle in epidermal cell walls of silicon-treated plants. Increasing levels of silicon were detected in the outer regions of epidermal cell walls. Silicon was present mainly in epidermal cell walls, middle lamella, and Intercellular spaces within subepidermal tissues. Furthermore, silicon was prevalent throughout the leaf surface with relatively small deposition on stomatal guard cells in silicon-treated plants. Force-distance curve measurements revealed relative hardness and smaller adhesion force in silicon-treated plants (18.65 uN) than control plants (28.39 uN). Moreover, force modulation microscopy showed higher mean height values of elastic Images In silicon-treated plants(1.26 V) than in control plants (0.44 V), implying the increased leaf hardness by silicon treatment. These results strongly suggest that silicon-induced cell wall fortification of rice leaves may be closely associated with enhanced host resistance to blast.

• Korean Journal Plant Pathology
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• v.1 no.3
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• pp.178-183
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• 1985

The present researches were carried out to investigate the peroxidase activity in association with the reactions of the 4 cultivars of rice plant, Nagdong, Jinheung, Nongbaek and Taebaek to Pyricularia oryzae race KJ-I0l and KJ-301. Although the peroxidase activity was increased during the growth of the rice seedlings, the significant difference in the activity was not found among 4 cultivars. After inoculation of the fungus, the peroxidase activity was enhanced in diseased leaves, being considerably higher in the compatible than in the incompatible cultivars. The isozyme bands of peroxidases observed in mycelium of rice blast fungus were not found in the diseased leaves on the gel electrophoresis. The peroxidase activity was not affected by the increased application of nitrogenous fertilizer.