• Journal of Plant Biology
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• v.36 no.2
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• pp.183-192
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• 1993

Efficient plant regeneration system was established through the culture of rice (Oryza sativa L.) microspores. Microspores released by anther shedding culture developed into proembryos and calluses in B5 medium within two weeks of culture. The optimal hormone and carbon sources were dependent on the genotypes used. Microspore's viability decreased rapidly in culture time, therefore less than 3% of the total microspores were viable at the 9th day when the first microspore division was observed. Of two types of microspores (pollen dimorphism) observed in culture, only the P-grain, larger microspores than normal one was able to divide. Using 4',6-diamidino-2-phenylindole (DAPI) fluorescence staining, it was confirmed that the symmetrical division of uninucleate microspore was the first step leading to continuous microspore development. Microspore-derived proembryos and calluses were regenerated to plants in N6 medium containing 1 mg/L NAA and 5 mg/L kinetin, and 78.3% of the regenerated plants were haploids.

• Journal of Plant Biology
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• v.14 no.2
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• pp.7-10
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• 1971

Haploid cell obta-ined from microspores of Solanum nigrum were cultured on two kinds of medium, "Callus-inducing medium" and "Differentiation medium", in order to conduct histological studies of callus and examine differentiation of plantlets. On the callus-inducing medium the calli grew rapidly. The bulk of callus mass was light brown colored "Wet callus" covered on the surface with thin layers of rough and gleaming "White callus". The wet callus was consisted of parenchyma and meristematic tissues, while the white callus had no meristematic tissues. Large parenchyma cells, by successive divisions, became multicellular or poly nucleate cells which developed later to be meristematic tissues. The calli embedded on the differentiation medium quickly turned to dark brown color. Plantlets, however, came out later from these blackened callus mass. In the callus sectioned about ten weeks after imbedding on the differentiation medium, radially elongated tissue, concentric tissue, epidermis, tracheid-like structure, and plant jprimordia were observed.ure, and plant jprimordia were observed.

• Journal of the Korean Society of Fashion and Beauty
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• v.3 no.2 s.2
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• pp.47-54
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• 2005

The purpose of this study was to investigate a specific character on products of American-cotton(Kobong) with cultivated in Sinbong-dong, Sangju City from 1997 to 2003 years. The results of this study were as follows: 1. The Kobong cotton of producted in Sangju city was superior in quality than Korean-cotton. 2. The cotton producted in 1998, 2002 and 2003 was inferior in quality than the anther producted cotton. The reasons was a heavy rain at 1998, Rusa typhoon at 2002 and Maemi typhoon at 2003 in sangju city. But Kobong-cotton was superior in quality than the Korean-cotton. Since it is so, Kobong(New improved variety of American-cotton) was superior in quality than the another kinds(Korean-cotton) from producted of cotton fibers

• Journal of the Korean Professional Engineers Association
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• v.39 no.3 s.186
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• pp.32-35
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• 2006

The recent speculation fever in Kangnam have been cooled down by the August 31 heavy taxation tool for curbing speculators. Another March 30 real estate control equipped with high capital gains tax up to 50% was targeting reconstruction projects of dilapidated apartment complexes mostly inside of Kangnam area. The shortage of larger unit supply with its high demand results in price polarization problem. It makes higher price for larger units and less price for smaller units, and therefore higher priced home owners become richer and lower priced home owners become poorer. To avoid the polarization problem and anther probable price hikes in the near future, it may be suggested to supply quality homes by loosening the tight rules for the apartment reconstruction project, and thereby kangnam housing price stabilization can be achieved.

• Journal of Plant Biology
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• v.13 no.3
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• pp.17-19
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• 1970

Histological observation of micropore-originated haploid rice callus was reported previously. Present study was attempted to clarify the growth or development of the calli when they were transferred to differentiation media prepared exclusively for differentiation of plantlets. When the callus was transferred to differentiation medium, the cells and tissues became radially elongated. Meristematic tissues were present but few in number, and their structures were quite different from those grown in the propagaton medium. Differentiation of tracheid, chloroplast, and epidermis-like cell layer, and formation of gap in the callus tissue were more conspicuous in differentiation media. Approximately ten days after transfer of callus to differentiation medium, plantlet was formed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.85-97
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• 1974

In order to clarify the inducing conditions and cause of sterility in rice plants, 4 varieties were cooled at 3 different levels of temperature combined with 3 different levels of treatment period. And 19 varieties were tested to examine the varietal difference of cold resistance. The results obtained were summarized as follows; 1. There were significant varietal differences in the effect of cooling treatment at meiotic stage. Suwon 213-1 was induced heavy sterility by 3 day cooling treatment at 17.5$^{\circ}C$ whereas Hayayuki, Nongpaik and Jinheung were induced a little sterility by 3 day cooling treatment at 15$^{\circ}C$ and 5 day treatment at 17.5$^{\circ}C$. The per cent of grain fertility was correlated significantly with the delayed days to heading, the degree of panicle extraction (Suwon 213-1, Nongpaik, Jinheung), culm length (Nongpaik, Suwon 213-1), and Auricle distance (Suwon 213-1). The degree of sterility was able to be estimated from the linear regression equation between the degree of panicle extraction (distance from panicle neck to flag leaf) and fertility percentage. In the case of heavy cold damage by the treatment of low temperature at meiotic stage, the rice plant had somewhat lower pollen density per anther, small and ununiform anther and pollen in size, and more sterile pollen grains. Suwon 213-1 showed anthesis in almost all spikelets, while Nongpaik, Jinheung and Hayayuki indicated considerable number of indehisced anther at 5 days after heading. 2. The fertility were not generally higher in cooling treatment at heading stage than at meiotic stage treatment. And significant correlation was found between the percentage of grain fertility treated at above two stages. Nongpaik and Jinheung were not affected in percentage of fertility by 5 day treatment at 15$^{\circ}C$ when these were treated at heading stage. Indehisced anthers were not found in Suwon 213-1 and Hayayuki, but Nongpaik and Jinheung showed more anthers which did not show anthesis 3. There was different varietal response to low temperature which was indicated by the decrease of grain fertility resulted from cooling treatment at meiotic stage. Jaekeun and Jinheung did not show low fertility but Milseong, Suwon 210, Satominoli and Suwon 213-1 showed outstanding decrease in fertility percentage by the cooling treatment at meiotic stage. The varieties which had low fertility were likely to have low pollen density per anther, abnormal anthers, small size po]]en grains and many sterile pollens. 4. Remarkable varietal difference of cold resistance was found in heading stage cooling treatment. Nongpaik, Jinheung, Jaekeun, Paltal, Akibare, Milseung and Palkeong were not affected in grain fertility by cooling treatments but Nonglimna No. 1, Suseong, Hayayuki, Suwon 213-1 and Suwon 210 showed significantly high sterility as treated by cool temperature. Most of the varieties showed higher fertility by cooling treatment at heading stage than meiotic stage but Hayayuki, Suseong and Nonglimna No.1 showed lower fertility when these were treated at heading stage than meiotic stage. There were two grops of varieties in the response to cooling treatment, one was somewhat non-anthesised and the other showed full anthesis. 5. In cold injury test of young seedlings, the result of observation was not accorded with the degree of growth inhibition. As a general, Palkeum and Suseong were highly torelant to cool temperature but Suwon 213-1, Jaekeun, Paltal, Shirogane, Palkeong, Mankyung were highly susceptible. 6. There is no significant correlation between the degree of young seedling cold damage and or the degree of growth retardation at seedling stage and grain fertility resulted from coding treatment both heading and meiotic stage.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.1-9
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• 1983

This study was conducted to obtain basic information on the rice anther culture. Materials used were (Inabawase X YR 2404-14-2-1) $F_1$ hybrid. Callus growth rate on various media, induction frequency of callus in spikelet and panicle, and the effect of treatment on anther and callus were evaluated. The results obtained were summarized as follows ; The growth rate of callus on N-6, M-S, P.E.agar media was 19.8, 13.1, 4.1 times respectively after 30 days inoculated, and on liquid media was 3.8, 5.1, 1.4 times, respectively. Organ differentiation on N-6, M-S, P.E.agar media was 37.5%, 12.5%, 17.5% respectively. The difference of induction frequency of callus per panicle was 0.14%-6.25% and per spikelet was 0-19.05%. Almost callus was induced 30-35 days after inoculation. Organ differentiation of induced callus was decreased by culture. Callus cultured for 13 days after induction did not make shoot. Anthers cold shocked at $8^{\circ}C$ for 5 days obtained 3.32% efficiencys of callus induction per number of anthers plated, and compared with 2.41% of no treated anthers. But anther treated at $8^{\circ}C$ for 7 days decreased 2.24%. Callus induction periods were shortened by cold treatment for about 5 days. Callus cultured on medium containing 2 mg/l of 2, 4-D showed 5% on root formation but medium containing 5 mg/l of 2, 4-D showed 30% of root formation after transfered on the medium without 2, 4-D. Callus cold shocked at $15-18^{\circ}C$ revealed poor efficiency for root formation, but 5 days treatment was good for shoot formation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.394-406
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• 1991

It was proved that cold tolerance of rice plants at the young microspore stage was affected by water temperature and nitrogen application from the spikelet differentiation stage to the young microspore stage, and this mechanism could be explained in the point of view of pollen developmental physiology. The cold tolerance of rice plants at the young microspore stage was severely affected by water temperature (Previous water temperature) and nitrogen application(Previous nitrogen application) from the spikelet differentiation stage to the spikelet differentiation stage. Although the duration is only 10 days or so from the spikelet differentiation stage to the young microspore stage, these days are very important period to confirm the cold tolerance of rice plants at the young microspore stage. The higher previous water temperature up to $25^{\circ}C$ and the deeper previous water depth up to 10cm caused the more cold tolerance of rice plants. Water irrigation of 10cm before the cretical stage showed lower cool injury than that of water irrigation of 20cm during the critical stage. The preventive effect of cool injury by combined treatment of the deep water irrigation before and during the critical stage was not additive but synergistic. The cold tolerance of rice plants grown in previous heavy nitrogen level was rapidly decreased when nitrogen content of leaf blade at the young microspore stage was excessive over the critical nitrogen level. Nitrogen content of leaf blade at the changing point of cold tolerance was estimated as about 3.5% for Japonica cultivars and about 2.5% for Indica x Japonica cultuvars. It is considered that these critical nitrogen contents of leaf blade can be used as a index of the safe critical nitrogen level for the preventive practices to cool injury. It was summarized that increase of engorged pollens per anther by high previous water temperature resulted from the increase of number of differentiated microspores per anther, otherwise, the increase of engorged pollens by the decrease of previous nitrogen level was caused by the decrease of the number of aborted microspores per anther.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.86-93
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• 1997

In order to induce somatic embryogenesis from the stem explants and anther of Kalanchoe daigremontiana, the explants were cultured on MS medium supplemented with auxin (2,4-D, IAA, NAA) and/or cytokinin (BAP) for 8 weeks. Callus from explants was induced most efficiently on MS medium containing. 2.0mg/L NAA and 0.2mg/L BAP. Somatic embryogenesis in stem callus was formed by transfering embryogenic callus from induction media containing growth regulators to medium without growth regulators and then to the medium containing auxin and cytokinin (0.1 mg/L IAA and 1.0mg/L BAP). Callus formation occurred actively in the anthers at early uninucleate stage, and by low temperature pretreatment at $4^{\circ}C$ for 3days. Somatic embryogenesis from the anther callus was induced on MS medium containing 1.0mg/L NAA and 1.0mg/L BAP, 2.0mg/L NAA and 0.2mg/L BAP. The tetraploid of 5.4% was obtained among plants regenerated from anthers.

• Korean Journal of Plant Tissue Culture
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• v.22 no.1
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• pp.35-39
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• 1995

In order to investigate the effects of gelling agent on rice anther culture, anthers of rice (Japonica cv Daecheongbyeo) were cultured on N$_{6}$ media supplemented with 0.8, 1.2 or 1.6% Junsei agar and 05, 0.4, 0.6, 0.8 or 1.0% Gelrite (Phytagel, Sigma). On Junsei agar media, the frequency of callus induction was decreased in proportion to agar concentration. The frequency of callus induction was more increased as 67.6% and 54.8% in media containing 0.4 and 0.6% Gelrite than in agar media. The frequency of plant regeneration and spontaneous doubled-diploid was directly proportional to Junsei agar and Gelrite concentration. The number of green and spontaneous doubled diploid plant was highest on 0.6% Gelrite medium. In order to optimize the concentration of growth regulators for the callus induction medium containing 0.6% Gelrite, anthers were cultured on N$_{6}$ media supplemented with 2mg/L NAA, 2 mg/L 2,4-D, 1mg/L NAA and 1mg/L 2, 4-D, or 1mg/L NAA, 1mg/L 2,4-D and 0.5mg/L kinetin. The maximum frequency of callus induction and plant regeneration was obtained from the medium supplemented with 2 mg/L NAA and 0.6% Gelrite. In conclusion the induction of embryogenic callus, the frequency of plant regeneration and in vivo chromosome doubling was more effective in Gelrite media than in Junsei agar media.dia.