• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.112-116
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• 2007

Kinetin(KN) is an inducer of rice(Oryza sativa L.) defense/stress responses, as evidenced by the induction of inducible secondary metabolite and defense/stress protein markers in leaf. We show a novel light-dependent effect of KN-triggered defense stress responses in rice leaf. Leaf segments treated with KN(100 ${\mu}M$) show hypersensitive-like necrotic lesion formation only under continuous light illumination. Potent accumulation of two phytoalexins, sakuranetin and momilactone A(MoA) by KN that peaks at 48 h after treatment under continuous light is completely suppressed by incubation under continuous dark. Using two-dimensional gel electrophoresis we identified KN-induced changes in ribulose-1, 5-bisphosphate carboxylase/oxygenase, energy- and pathogenesis-related proteins(OsPR class 5 and 10 members) by N-terminal amino acid sequencing and mass spectrometry. These changes were light-inducible and could not be observed in the dark(and control). Present results provide a new dimension(light modulation/regulation) to our finding that KN has a potential role in the rice plant self-defense mechanism.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.3-10
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• 1981

In order to analyze growth and yield of rice population at the stand point of productive ecology, productive structure and growth rate of rice plants and effects of their related factors were studied. The results obtained were summarized as follows: 1. High crop growth rate was maintained throughout growing season when rice plants grew in population compared to a single rice plant. Since crop growth rate in rice stands were also higher at ripening stage, higher yields were obtained. 2. Higher crop growth rate of rice plants in population was maintained by the increase of leaf area rather than by net assimilation rate. 3. As the overgrowth of upper leaves of plant population in some rice varieties transmission of light into lower leaves was inhibited and thus most of them were eventually died before flowering. 4. In the case of rice population, the ratio of productive organ to non-productive organ, light transmission rate and nitrogen contents of active leaf blade were lower than individual rice plants under isolated condition.

• Plant Resources
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• v.1 no.1
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• pp.43-48
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• 1998

The objective of this study was to determine how elevated $CO_2$ and temperature affected early growth and competition between direct seeded rice (Oryza sativa) and a common paddy weed (Echinochloa glabrascens). By using temperature gradient chambers. Rice and E. glabrescens were grown for 5 weeks at ratios of 1:0. 3:1 and 0:1 at three temperatures ($16.4^{\circ}C,\;19.8^{\circ}C,\;and\;22.2^{\circ}C$) and either in ambient (361ppm) or elevated (566ppm) $CO_2$. For both species. elevated $CO_2$ had no effect on mainstem leaf number while air temperature had a slight positive effect which was greater in E. glabrescens than rice. With elevated $CO_2$ rice leaf area index and plant height increased alightly in all species combinations but no increases were observed for E. Glabuescens. For rice in all combinations. elevated $CO_2$ tended to increase the rot and total biomass much more than any other growth parameters: the increases in root and total biomass resulting from elevated $CO_2$ ranged from 16% to 40%. depending on air temperature. At the lowest temperature, the decrease in rice biomass in combination with E. glabrescens was significantly greater at elevated $CO_2$ (18%) than ambient $CO_2$ (3%). At the highest temperature, however, the decrease in rice biomass at elevated $CO_2$ (22%) was less than that at ambient $CO_2$ (36%). The competitive ability of rice as measured by the decrease in biomass when grown in combination with E. glabrescens depended strongly on root growth and/or allocation. These results suggest that at higher temperatures elevated $CO_2$ could enhance the competitive ability of direct seeded rice during early growth. However, at lower temperatures. the competitive ability of E. glabrescens seems to be greater.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.731-737
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• 1995

This experiment was carried out at National Crop Experiment Station in 1994 to obtain basic information of growth characters and yield of rice under various nitrogen split application methods on different soil textures in direct seeding on dry paddy. Hwaseongbyeo sown on April 27 by flat drill seeding, and irrigation was done at 3 leaf stage after seedling establishment. Number of seedling stand was 159~177 seedlings per $m^2$ regardless of soil texture and nitrogen application method. Number of panicle per unit area in loam was higher than in sandy loam, and it also was higher in top dressing plots, which were 3 times application at rate of 40-30-30% (3rd leaf stage -7th leaf stage -panicle initiation stage) and 4 times application 10-30-30-30%(basal-3rd leaf stage -7th leaf stage -panicle initiation stage), than in conventional method. Leaf colour, leaf area index and dry matter production at heading stage were highest at top dressing plots among the nitrogen application methods in both sandy loam and loam. Lodging index in top dressing plots increased by low breaking weight with long culm. There were field lodging of degree 3 in top dressing plots. Rice yield in sandy loam, loam increased by 7~9%, 6~9% in top dressing of nitrogen, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.206-217
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• 1982

This experiment was conducted to study about nutrient absorption of flag leaf and chaff of rice plant different transplanting date with elevations. Heading stage was delayed by destructive cold temperature or late transplanting. Plant analyses revealed that above poor plants also had higher total nitrogen content, but ower silicate in the flag leaf and sterile chaff. Total nitrogen and silica contents to accumulated in flag leaf between yield was significant high correlation. The chaff of late transplanting and sterility was high total nitrogen. Relationship between silicate absorption and total nitrogen of chaff was significant high correlation. Ripening temperature after heading stage was influenced total nitrogen of chaff. Phosphate, potassium, calssium and silicate contents of chaff increased hight ripening temperature but total nitrogen decreased. Therefore, inorganic element contents of chaff was closely connected with grain sterility.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.90-94
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• 1997

Interaction of races of rice blast fungus and cultivars has been evaluated. Dongjinbyeo was infected by four KJ races and two KI races, while other varieties were susceptible to four to six KJ or KI races. Among the single spores reisolated from the leaf blast lesion of Dongjinbyeo after mixed inoculation of 10 races, 63% was race KJ-301 which produced a small number and small size lesions, while 30% was race KI-313 which produced a large number of lesions. However, 93% of single spores reisolated from Palgongbyeo was a highly virulent race KJ-105. On the other hand, all the races were equally reisolated from the susceptible cultivar Jinmibyeo. Frequency of races isolated from the naturally infected leaf blast lesions in the field was similar to that of reisolated races from the cultivars inoculated with 10 mixed races in the greenhouse. However, 30% of single spores isolated from the naturally infected Dongjinbyeo was race KI-329 ut ace KI-313 was not detected. Genetic relationship of the isolates collected from leaf and neck blast fungus of Jinmibyeo and Nakdongbyeo showed specific bands on RFLP-P64, However, their genetic similarity was 80%.

• Korean Journal of Organic Agriculture
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• v.6 no.1
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• pp.127-132
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• 1997

This experiment was carried out to examine the effect of various functional materials such as bioceramic podwers, crushed shells and elvanites supplemented to the each substrate on the seedlings growth of rices. The rice seedlings were grown in pots filled with substrates supplemented with bioceramic podwers, crushed shells and elvanites. The growth of rice seedlings in terms of plant height, stem diameter, root length and leaf width, plant fresh and dry weight was promoted by adding the bioceramic powders (2 to 3g/kg), crushed shells (10g/kg) or elvanites (20 to 40g/kg). Plant height was also promoted by the adding of bioceramic powder from 16 days after treatment, whereas crushed shells and elvanites from 10 days after treatment. Especially, root growth was greatly influenced by bioceramic powder, whereas the shoot growth(leaves and stem) was stimulated by the crushed shells and elvanites supplemented into each substrate. In the field, plant growth in terms of plant height, leaf length and leaf width were also influenced by crushed shells and elvanites at 74 days after treatment. The growth of rices in terms of tiller number, spikelets, panicles and spikelets/panicle was incresed by adding the crushed shells and elvanites from 100 to 200g per m2.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.225-232
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• 2024

The microbiomes of two important rice cultivars in Vietnam which differ by their susceptibility to the bacterial leaf blight (BLB) disease were analyzed through 16S rRNA amplicon technology. A higher number of operational taxonomic units and alpha-diversity indices were shown in the BLB-resistant LA cultivar than in the BLB-susceptible TB cultivar. The BLB pathogen Xanthomonas was scantly found (0.003%) in the LA cultivar, whereas was in a significantly higher ratio in the TB cultivar (1.82%), reflecting the susceptibility to BLB of these cultivars. Of special interest was the genus Acholeplasma presented in the BLB-resistant LA cultivar at a high relative abundance (22.32%), however, was minor in the BLB-sensitive TB cultivar (0.09%), raising a question about its roles in controlling the Xanthomonas low in the LA cultivar. It is proposed that Acholeplasma once entered the host plant would hamper other phytopathogens, i.e. Xanthomonas, by yet unknown mechanisms, of which the triggering of the host plants to produce secondary metabolites against pathogens could be a testable hypothesis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.199-202
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• 2000

The leaf color varies with the contents of pigments, especially chlorophylls and carotenoids. Teichung 65 (T.65), a japonica rice, with pgl(pale-green leaf) gene exhibits pale green color on the whole plant from seedling to harvest. This study conducted to evaluate the agronomic characters and examine the chloroplasts of 'pgl' plants in parents and BC$_1$F$_2$ of T.65(pgl) xSuweon ${345}^2$. The average grain yield of pale-green-leaf individuals in F$_2$ was the same as T.65(pgl) but that of green-leaf individuals was much higher than that of Suweon 345. The contents of chlorophyll a(Ca), chlorophyll b(Cb) and total chlorophyll content(Ct) of T.65(pgl) in flag leaf were lower than those of Suweon 345, but the Ca/Cb ratio of T.65(pgl) was higher than that of Suweon 345 during from 15 days after heading (DAH) to 60 DAH. The SPAD value of T.65(pgl) in flag leaf was lower than that of Suweon 345, but that in the second and the third leaves was similar to that of Suweon 345. The SPAD value of pale-green-leaf individual group was lower than that of green individual group in upper three leaves. The structural difference of chloroplasts in flag leaf between T.65(pgl) and Suweon 345 through TEM at 20 DAH was not detected, but the number of osmium granules in chloroplast of T.65(pgl) were higher than that of Suweon 345.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.5
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• pp.348-351
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• 2001

This study was conducted to evaluate the control effect of fungicides on control of brown leaf blight, growth characteristics, and dry root yield in the cultivation of Alisma plantago after early maturing rice cropping. All fungicides treated had no effect on the growth and flowering rate of Alisma plantago. The major fungicides were mancozeb Wp, 75%, chlorothalonil Wp, 75%, dithianon Wp, 43%, difenoconazole Wp, 10%, benomyl Wp, 50%, and propineb Wp, 70%. Dry root of yield were increased largely with chlorothalonil Wp, 75%(33 g/20), fungicide than the other fungicides and control. All fungicides had no injury with standard dosage. On the other hand all fungicides had slight injury in the double dosage level for the Alisma plantago.