• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.759-765
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• 1997

The process of the senescence in Oryza glaberrima Steud. strains and Oryza sativa L. cultivars were examined in terms of SPAD value(chlorophyll content) and photosynthetic rate. SPAD values and photosynthetic rates of flag leaves for 10 genotypes of each species was measured at the 1, 3 and 5 weeks after heading. SPAD values and photosynthetic rates of O. glaberrima strains tended to decrease rapidly after heading. O. sativa cultivars showed slower decrease as compared to O. glaberrima strains, in particular during the period from 1 to 3 weeks after heading. Although there was no significant difference between the two species in the mean value of photosynthetic rate and SPAD value at 1 weeks after heading, O. glaberrima had lower values after 3 weeks after heading. There were significant positive correlation coefficients between the photosynthetic rate and the SPAD value at 1 and 3 weeks after heading for O. glaberrima strains, and at 1 and 5 weeks after heading for O. sativa cultivars. There were significant positive correlation between the decreasing rates of the photosynthetic rates and the decreasing rates of the SPAD values at the period from the 1 to 3 weeks after heading for both species. At the period from 3 to 5 weeks after heading, only O. glaberrima showed a significant correlation between two traits, indicating that rapid decrease in chlorophyll content would affect the photosynthesis in O. glaberrima.

• Proceedings of the Botanical Society of Korea Conference
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• 1999.04a
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• pp.17-17
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• 1999

• Korean Journal of Plant Resources
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• v.27 no.3
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• pp.249-255
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• 2014

The rice belonging to Oryza sativa is not only has significant economic importance, for it is the major source of nutrition for about 3 billion all around the world. But also plays a vital role as a model organism, because it has a number of advantages to be a model plant, such as efficient transformation system and small genome size. Many methods and techniques have been conducted to attempt to distinguish different Oryza sativa species, such as amplified fragment length polymorphism (AFLP), random amplified polymorphic DNA (RAPD), simple sequence repeat (SSR) and so on. However, studies using sequence analysis of internal transcribed spacer (ITS), a region of ribosomal RNA has not been reported until now. This study was undertaken with an aim to understand the phylogenetic relationships among sixteen isolates of Oryza sativa collected from abroad and fifteen isolates collected from Korea, using ribosomal RNA (rRNA) internal transcribed spacer (ITS) sequences to compare the phylogeny relationships among different Oryza sativa species. The size variation obtained among sequenced nuclear ribosomal DNA (nrDNA) ITS region ranged from 515bp to 1000bp. The highest interspecific genetic distance (GD) was found between Sfejare 45 (FR12) and Anapuruna (FR15). Taebong isolate showed the least dissimilarity of the ITS region sequence with other thirty isolates. This consequence will help us further understanding molecular diversification in intra-species population and their phylogenetic analysis.

• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.119-122
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• 2002

Oryza sativa cv. Mihyangbyo is one of several recently developed varieties of rice; characterized by high levels of aromatic components, which may increase its sensory and nutritional properties. In conjunction with our continuing investigation of bioactive components of improved grain varieties, a quinolone alkaloid was isolated from the n-butanol soluble fraction of the aleurone layer of Oryza sativa cv. Mihyangbyo (Gramineae) through activity-guided fractionation and isolation. The compound exhibited moderate antineoplastic activity in a human leukemia cell line (U937) with an $IC_{50}$/ value of 118.1 ug/mL, based on the MTT(3-[4, 5]dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) cell proliferation assay. The chemical structure of the functional compound was determined, based on physical and spectroscopic characteristics.

• Proceedings of the Botanical Society of Korea Conference
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• 2002.04a
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• pp.102-102
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• 2002

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3756-3759
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• 2011

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.739-741
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• 2009

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.65-70
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• 2010

We describe the immune stimulatory effects of compounds determined by means of activity-monitored extraction and isolation techniques. As a result, 4-carboethoxy-6-methoxy-2-quinolone (1) and 4-carboethoxy-6-hydroxy-2-quinolone (2) were isolated from the ethyl acetate-soluble fraction of the Oryza sativa cv. Heugnambyeo bran, and were determined to exert significant inhibitory effects in macrophage cell line (murine RAW 264.7) and murine splenocytes. The structures were elucidated on the basis of spectroscopic evidence, particularly the results obtained via hetero nuclear multiple-bond connectivity and high-resolution MS spectroscopy. Up to date, compound (1) was isolated as natural sources for the first time.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.276-280
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• 2008

Oryza sativa cv. Heugjinjubyeo, an anthocyanin-pigmented rice variety, is well known to contain high levels of bioactive phytochemicals, anthocyanin, quinolone alkaloids and phenolic acids. Here, we studied the inhibitory effect of Oryza sativa cv. Heugjinjubyeo bran on the absorption of dietary fat in streptozotocin-induced diabetic Sprague-Dawley male rats. For these experiments, experimental animals were divided into four groups: normal, diabetic-control and two experimental groups that were fed 1.0 g or 2.0 g/kg body weight/day of Oryza sativa cv. Heugjinjubyeo bran supplement for 14 days. As a result, liver glycogen levels increased significantly by 65% and 32% in groups receiving 1.0 g and 2.0 g/kg body weight/day, respectively, compared to diabetic-control. Liver cholesterol levels were significantly lower by 8.3% and 14.5% in the groups fed 1.0 g and 2.0 g of anthocyanin- pigmented rice extracts, respectively.

• Applied Biological Chemistry
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• v.36 no.5
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• pp.376-380
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• 1993

To investigate the presence of the brassinosteroid substances in immature Oryza sativa L. cv Tongjinbyeo seeds, the methanol extract was purified by the sequential use of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography and charcoal adsorption chromatography. The activity of brassinosteroid was monitored by the rice inclination test and its presence could be confirmed in each purification step. The purified active components were separated by silica gel adsorption chromatography and Sephadex LH-20 chromatography. Brassinosteroid substances in separated active fractions were identified as castasterone, teasterone and 6-deoxocastasterone by HPLC. Our work is probably the first report of endogenous brassinosteroids in Oryza sativa seeds. The content of brassinosteroid in Oryza sativa seeds as converted into brassinolide was $0.5{\sim}1.5\;ng/g$ fresh weight.