• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.1
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• pp.22-29
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• 2020

Rice is very sensitive to high temperatures during the reproductive stage, particularly during the flowering and anthesis periods. To determine how high temperatures result in sterility during the flowering period in Korean rice cultivars, groups of 11 cultivars were subjected to different temperature regimes (24, 28, 30, and 33℃) during the flowering stage using sunlit phytotrons. At an average of 33℃, all 11 rice cultivars reached anthesis earlier than at the other temperatures. Microscopy analyses revealed significant differences in pollen germination and pollen viability in cultivars grown at 33℃ compared to those cultured at lower temperatures. At 33℃, the cultivars had significantly lower fertility rates (47% reduction) than cultivars grown at 24℃. These findings are important as rice pollination and fertility depend on the pollen viability and germination. The present study shows that rice fertility is negatively affected by excessively high temperatures.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.101-106
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• 1997

This study was carried out to examine the possibility of using brown rice or paddy as raw materials for sikhe. Brown rice and paddy were soaked in water at $15^{\circ}C$ for 2 days and then germinated at $15,\;20,\;25,\;30^{\circ}C$ for upto 10 days. The higher the germination temperature, the higher the germination speed, the increase of ${\alpha}-amylase$ activity, and the increase of extract amount and its sugar content. The viscosity of extract rapidly decreased first and then slightly increased during germination. The activities of ${\alpha}-amylase$ of germinated brown rice and paddy were much smaller than those of germinated barley; however, the extract amount and its sugar content of germinated brown rice and paddy were similar to those of germinated barley. The germinated brown rice can be used for sikhe not as a saccharifying agent but as a substitute for white rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.696-701
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• 2016

This study was conducted to evaluate the effects of heat treatment and germination on tricin and tricin 4'-O-(threo-${\beta}$-guaiacylglyceryl) ether (TTGE) formation from rice hull (Oryza sativa L.). Heat treatments were conducted at $80{\sim}140^{\circ}C$ for 1~5 h. Germination periods were 1~6 days at $37^{\circ}C$. Germinated rough rice extracts were classified as non-filtrated, filtrated, and residue after filtration. For heat treatment, the highest contents of tricin and TTGE were 253.12 and $208.39{\mu}g/g$ at $130^{\circ}C$ after 1 h, respectively. For germination, the highest contents of tricin and TTGE in rice hull were 118.20 and $95.37{\mu}g/g$ after 2 days, respectively. In the germinated rough rice extract treatment, the highest contents of tricin and TTGE were 361.76 and $308.08{\mu}g/g$, respectively, in residue after filtration of germinated rice extract for 6 days. Therefore, the optimum conditions for tricin and TTGE formation were heat treatment at $130^{\circ}C$ for 1 h, germination for 2 days, and addition of residue after filtration of germinated rough rice extract for 6 days.

• Journal of Life Science
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• v.25 no.2
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• pp.158-163
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• 2015

Rice embryo is more abundant than endosperms in nutrients such as proteins, lipids, and vitamin B1. In this study, we constructed p53 plasmid that could be expressed in a plant system, and investigated optimal germination conditions in a variety of media. For construction of p53 plasmid, we performed p53 amplification from pCDNA-p53, subcloned to TA cloning vector, and then reconstructed into pGEM-CaMV plant expression vector. On the other hand, we prepared a variety of imbibition buffers and complete media for efficient germination of the rice embryo. Imbibition buffers prepared with different concentrations of salt or detergent showed no significant effect on germination efficiency. We prepared further culture media, such as solid agar, liquid media, and paper towel to establish the optimal conditions. Rice embryo showed germination rates of more than 70% in the solid medium, more than 60% in the paper towel medium, but less than 25% in liquid media, although germination rate did not differ with varying concentrations of salt and sucrose in culture media. Under the optimal germination conditions, we introduced the p53 plasmid using imbibition method, and finally detected human p53 gene expression in the germinated rice embryo. This method might present a novel, practical approach for evaluating efficient gene expression utilizing imbibition method in rice embryo.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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• pp.287-293
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• 1993

This study was carried out to investigate the influences of cultural conditions of koji on the production of organic acid during rice-koji making by Aspergillus awamori var. kawachii which is now widely used as koji-mold in brewing Takju and Yakju in Korea. The optimum temperature for the germination of the conidia of the mold was 35'8, and the time required for germination at this temperature was 8 hours. Rapid germination occurred when the water content of steamed rice was above 40%, but germination retardation occurred markedly below 35%. The optimum cultural temperature for the production of organic acid was 32$^{\circ}C$, and the production of organic acid was markedly restricted at 36$^{\circ}C$ and 4$0^{\circ}C$. It was effective for the high production of both saccharogenic amylase and organic acid to shift the cultural temperature from initial 36$^{\circ}C$ to 32$^{\circ}C$ after 20~25 hours of cultivation. Initial water content suitable to the production of organic acid was 40% in steamed rice, but its production was markedly restricted below 30% of water content. When the quantity of conidial inoculation was too small, the production of organic acid was low in initial phase, but it was retrived at later period. Acid production was markedly restricted together with the increase in koji thickness.

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.511-515
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• 2010

It was conducted to assess GABA(${\gamma}$-aminobutyric acid) producing capacity and vitamin contents of germinated brown rice soaked in different soaking solutions. For germination, samples were soaked in 5% glutamic acid solution and 5% lactic acid solution as test group to investigate GABA producing capacity, and samples soaked in the solution without glutamic acid and lactic acid were set as control groups(rice and non-germinated brown rice). The GABA contents of the samples were $44.80\;{\mu}g/g$ for rice, $59.90\;{\mu}g/g$ for non-germinated brown rice, $146.70\;{\mu}g/g$ for germinated brown rice, $203.20\;{\mu}g/g$ for germinated brown rice soaked in glutamic acid solution and $222.5\;{\mu}g/g$ for germinated brown rice soaked in lactic acid solution, resulting in a significant difference(p<0.05). GABA producing capacity was enhanced by the addition of glutamic acid and lactic acid in the soaking solution for brown rice germination. The GABA contents of the germinated brown rice soaked in lactic acid solution greatly increased, along with increases in niacin and vitamin E contents without losing vitamin $B_1$. In conclusion, the addition of lactic acid in soaking solution is most suitable for germination of brown rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.3
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• pp.194-198
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• 1998

An experiment was carried out to find out the priming effects of rice seeds, Oryza sativa L. (cv. Ilpumbyeo) on. the seedling establishment and early emergence under excess soil moisture conditions. Seeds were primed by soaking in -0.6 MPa polyethylene glycol (PEG) solution at $25^{\circ}C$ for 4 days. The primed seeds were sown in soils with various soil moistures (60, 80, 100, 120, and 140% field capacity) at 17 and $25^{\circ}C$, respectively. Germination and emergence rates, plumule height, and radicle length of primed seeds were higher than those of untreated seeds at any soil moisture and temperature examined. The time from planting to 50% germination ($T_{50}$) of primed seeds was less than that of untreated seeds by 0.9～3.7 days. Germination rate, emergence rate, plumule height, and radicle length were highest at the soil moisture of 80% field capacity among the soil moistures. Priming effects of rice seeds on germination and emergence rates were more prominent under the unfavorable soil moistures (60, 100, 120, and 140% field capacity) than those under the optimum soil moisture condition (80% field capacity). However, priming effects on seedling growth were greater at near optimum soil moisture compared with too lower or higher soil moistures. Therefore, these findings suggest that priming of rice seeds may be a useful way for better seedling establishment under the adverse soil conditions.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.462-469
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• 2005

Effects of proton beam irradiation on seed germination and growth pattern of tobacco (Nicotiana tabacum L. cv. BY-4; N. plumbaginifolia) and rice (Oryasativa L.) plants were estimated to develop the efficient conditions of irradiation. Seed germination rate was decreased by increasing the proton beam the current and the beam irradiation time in both tobacco and rice seeds. The beam irradiation conditions showing $50\%$ germination were over 60 sec at 10 nA, approximately 5 sec at 100 nA and at 500 nA beam current in tobacco seeds. And the conditions of $50\%$ germination were 60 sec at 10 nA, and 100 nA and 30 sec at 500nA in rice (cv. Dongjin 1) seeds. The growth of irradiated plants was decreased, but significant difference in morphological changes was not observed by the proton beam treatment. The proton beam is able to use as a mutagen, but some of the factors including beam size and beam detector-system must be established for efficient usage of the beam.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.565-570
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• 2006

The viviparous germination (VG) with lodging caused the yield reduction and quality deterioration in rice. We carried out the evaluation of VG tolerance (on the 40th day after heading) and mapping QTLs associated with VG tolerance using the recombinant inbred lines (M/G RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). The VG rates of Milyang 23 and Gihobyeo were 0.0 and 7.0%, respectively. The averaged VG rate of 162 M/G RILs was 7.7%, and their range was from 0.0 to 50.9%. Of the 162 RILs, 144 lines were tolerant less than 10%, and 18 lines were susceptible more than 10%. Using the M/G RIL Map, three QTLs associated with the viviparous trait were detected on chromosome 2 (qVG 2-1 and qVG 2-2) and 8 (qVG 8). qVG 2-1 was linked to RM 32D and RZ 166, and had LOD score of 2.97. qVG 2-2 was tightly linked to E13M59.119-Pl and E13M59.M003-P2, and showed higher LOD score of 3.41. qVG 8 was linked to RM33 and TCT116, and had LOD score of 2.67. The total phenotypic variance explained by the three QTLs was about 24.4% of the total variance in the population. The detection of new QTLs associated with VG tolerance will provide important informations for the seed dormancy, low temperature germination, or comparative genetics.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.333-338
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• 2013

Enzymatic activity in germinated cereal grains is important for the saccharification of starch materials. This study was conducted to investigate the amylolytic activities of germinating brown rice and black rice that have different amylose contents. Brown rice and black rice were steeped at room temperature for 24 h and germinated at 20 and $30^{\circ}C$ for 1, 2, and 3 days. ${\alpha}$- and ${\beta}$-Amylase activities in normal brown rice increased very slightly during the 3-day germination period, but the enzymatic activities were slightly higher in low-amylose (waxy type) brown rice. Diastatic power (DP), a measure of starch-saccharifying enzyme, was higher in the germinating brown rice with low amylose than in those with normal amylose content. ${\alpha}$- and ${\beta}$-Amylase activities in black rice increased gradually during germination, and DP of low-amylose black rice appeared to be higher than that of normal brown rice. Amylase activities in brown rice and black rice germinated at $30^{\circ}C$ were higher than those germinated at $20^{\circ}C$. Compared to brown rice, the overall amylolytic activity of germinated black rice was observed to be higher than that of brown rice.