• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.46-54
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• 1997

Sporulation in the fission yeast Schizosaccharomyces pombe has been regarded as an important model of cellular development and differentiation. S. pombe cells proliferate by mitosis and binary fission on growth medium. Deprivation of nutrients especially nitrogen sources, causes the cessation of mitosis and initiates sexual reproduction by malting between two sexually compatible cell types. Meiosis is then followed in a diploid cell in the absence of nitrogen source. DNA fragment complemented with the mutations of sporulation gene was isolated from the S. pombe gene library constructed in the vector, pDB 248' and designated as pDB (spo 5)1. We futher analyzed six recombinant plasmids, pDB (spo 5)2, pDB(spo 5)3, pDB(spo 5)4, pDB(spo 5)5, pDB(spo 5)6, pDB(spo 5)7, and found each plasmids is able to rescue the spo 5-2, spo 5-3, spo 5-4, spo 5-5, spo 5-6, spo 5-7, mutations, respectively. Mapping of the integrated plasmid into the homologous site of the S. pombe chromosomes demonstrated that pDB (spo 5)1, and pDB (spo 5)R1 contained the spo 5 gene. Transcipts of spo 5 gene were analyzed by Northern hybridization. Two transcripts of 3.2 kb and 25 kb were detected with 5 kb Hind III fragment containing a part of the spo 5 gene as a probe. The small mRNA (2.5 kb) appeared only when a wild-type strain was cultured in the absence of nitrogen source in which condition the large mRNA (3.2 kb) was produced constitutively. Appearance of a 2.5 kb spo 5-mRNA depends upon the function of the mei1, mei2 and mei3 genes.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.25-34
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• 1979

To clealify the cause of barley and wheat sterility that occurred 77 / 78 cultivation period in Yeongnam area, a few environmental conditions were analyzed. The results are summarized as follows; 1. During the important growing stages such as meiosis and heading stages of barley encountered with severe droughtiness and unusual low temperature. 2. Soil moisture contents in the double cropping paddy soils were higher than cultivated uplands, and in the subsoils than the surface soils, in the clay soils than the sandy soils, in the northern aspect than the southern aspect of slope, respectively. 3. The sterilizing percentage of barley in the double cropping paddy fields were lower than cultivated uplands, in the alluvial fans and plains were lower than cultivated uplands, in the alluvial fans and plains were lower than in rolling or in foot slopes and the northerm aspect of slopes were lower than southern aspect. 4. The sterilizing percentage in the sandy soils were higher than clay soils and in the soils that have shallower plowing layer and shallower available depth had higher sterility. 5. The sterilizing percentage of barley had negative correlation with soil moisture contents in the surface and subsoils in both of cultivated upland or double cropping paddy fields. 6. The droughtiness that prevailed over reproductive growing stages of barley might be cause the sterility and the severe coldness also could be accelerate the phenomenon.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.201-209
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• 1982

In 1980, the abnormal low temperature was lasted during the late stage of rice growing season, thus low temperature injury occurred severely. The severity of the injury and nutrition absorption were investigated. The result obtained were summarized as follows: 1. It was considered that the severe low temperature injury of rice was caused by the low temperature and shorts of sunshine in the late growing season of rice, especially, the minimum air temperature which was lasted for a few days below critical reproductive growing temperature in the meiosis stage affected high the injury. 2. The low tmperature injury was lightened in the no nitrogen applied plot, and becoming severe with high nitrogen levels, but the balanced application of NPK lessened the low temperature injury. 3. The low temperature injury was more severe in Indica and Japonica hybrid than in Japonica cultivar, and the injury was shown as sterilizing, degraded spiklets, ill emerging of head and inhibition of nutrition absorption, etc. 4. Under the low temperature condition, $SiO_2$ content of rice plant was significantly reduced according to the increase of nitrogen levels. 5. Under the low temperature condition, the optimum application amount of nitrogen for Milyang 23, was 13, 6 kg/10a, this was approximately 10kg/10a smaller than average in usual year. The highly reduced rice yield was resulted from the cool injury, and the reducing rate of yield was larger in Indica and Japonica hybrid cultivar than in Japonica cultivar.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.125-131
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• 2006

This survey was carried out to investigate the characteristics of low temperature injury in rice plants at a southwestern alpine area of Korea in 2003. During vegetative, reproductive, and ripening stage in a southwestern alpine area, mean air temperature was lower by 0.4, 3.1 and $1.7^{\circ}C$, respectively, as compared to those of a normal year, Minimum air temperature during the reproductive and ripening stage was lower by 2.6 and $1.7^{\circ}C$, respectively, as compared to those of a normal year, Sunshine hours during vegetative, reproductive, and ripening stage were lower by 40.6, 81.3 and 8.4 hours, respectively, than those of a normal year. Spikelet-sterility type cold injury occurred from the latter part of June to the middle of July, which is from panicle formation stage to meiosis stage, at temperatures less than $17^{\circ}C$. Spikelet sterility under normal transplanting (May 20) ranged from 16 to 58%, which was lower than that under early transplanting in the latter part of April (29 to 83%). The total area impacted by cold damage was 2,723ha in Namwon, 510ha in Sunchang, 300ha in Jinan, 250ha in Muju, and 210ha in Jangsu. Average spiklet sterility in these regions was 44%. Rice cultivars Odaebyeo, Unbongbyeo, and Jinbubyeo showed greater tolerance to low temperature than CV, Chugwangbyeo.

• Korean Journal of Plant Resources
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• v.19 no.4
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• pp.497-508
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• 2006

This study was conducted to obtain the basic information on rice cold damage and relationship to be connected with cold tolerance. The 20 rice varieties were screened to cold tolerance under low water temperature condition. The water gradient were controlled to $17^{\circ}C$ at the inlet and $21^{\circ}C$ at outlet of screening field. In the relationship between cold water irrigation and growth of rice varieties, effect on medium maturing cultivars were higher than early maturing cultivars. In relationship of shorting of culm length and panicle exsertion, culm length and panicle exsertion showed positive correlation. Yield of cultivars and culm length and percent of fertile grain showed positive correlation. However, heading date presented negative correlation. In the early maturing cultivars, except 'Kumobyeo', all cultivars range of discoloration value (1-3) was resistant. In the medium maturing cultivars, 'Donghaebyeo' was resistant in both the seedling stage whereas 'Hwajinbyeo' was resistant only in tiller stage. Cold water irrigation reduced spikelet number per panicle and percent of filled grain. Unhulled rice yield was increased according to water temperature gradient from inlet to outlet. There was varietal differences in head rice recovery by cold water treatment.

• Korean Journal of Weed Science
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• v.7 no.1
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• pp.98-106
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• 1987

The effect of carbofuran (2, 3-Dihydro-2,2-dimethyl-benzofuran-7-ylmethyl carbamate) on rice growth was evaluated as a direct growth stimulant of rice. For this, several laboratory and field trials conducted from 1981 to 1986 at the Yeongnam Crop Experiment Station. Carbofuran solution affected the germination of rice seed. The growth of seminal roots was adversely affected by the increase of carbofuran concentrations while the length of single root became longer with the concentration increment up to 50 ppm. Carbofuran application (0.18g ai/$m^2$) at the rice nurserybed significantly enhanced the rice growth and recovered from the Low temperature damage. The enhancement effect was more pronounced at the plot that applied carbofuran before rice seeding as soil incorporation than top-dressing. The effect of growth enhancement further extended to transplanted lowland rice. This effect was greater at double cropping area (late of June transplanting) compared to single cropping area (May transplanting). Among important agronomic traits, the increment of panicle number was the most important direct effect for increasing rice grain yield by carbofuran application. Carbofuran application also exhibited the reducing effect against low temperature damage at reductive division stage and at rice heading stage and against submergence damage at booting stage through enhancement of fertile grain ratio, ripening ratio or photosynthetic activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.242-248
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• 1986

To study the effect of cold water irrigation at the reproductive growth stage of rice plants on several growth characters related to source and sink and nutrient uptake, the present experiment was carried out under the different conditions of water temperature and water depth. Deep irrigation with normal temperature water increased culm length, panicle length and panicle exsertion but with cold water resulted adversely. Most sensi-tive response in 5 cm water-depth appeared at reduction division stage and in 20 cm depth at panicle formation stage. Secondary branches and spikelets were increased in number by deep irrigation with normal temperature water, but decreased and degenerated by deep irrigation with cold water at panicle formation stage resulting in high spikelet sterility and low grain filling. Deep irrigation with normal temperature water increased the contents of total nitrogen, phosphate, potassium and silicate in leaf blades, branches and chaff. However, cold water irrigation reduced the uptake of phosphate, potassium and silicate except nitrogen particularly in deep irrigation. Ratios of phosphate, potassium and silicate to total nitrogen content were decreased by cold water irrigation. Branches seemed to have higher requirements for phosphate, potassium and silicate than leaf blades and chaff. Silicate-to-total nitrogen ratio in leaf blades, branches and chaff had significant correlations with yield showing closer relationship between yield and the ratio of silicate to total nitrogen in branches in particu-lar.

• FLOWER RESEARCH JOURNAL
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• v.16 no.1
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• pp.12-16
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• 2008

This study was carried out to produce haploid plants to verify a systematic breeding program and genetic analysis. Effect of developmental stage of pollen grains and pre-treatment temperature on production of haploid plants was investigated. Microscopic investigation of the explants (Lilium Asiatic hybrid 'reamland' revealed that the length of flower bud at 23.0-24.9, 25.0-26.9, and 27.0-28.9 mm long coincided with tetrad, uninucleate, and binucleate, respectively. When the efficiency of the anther culture from microgametogenetic stages was tested, late uninucleate to early binucleate stage, having the length of 23.0 to 28.0 mm long flower bud, was the best. The frequencies of the callus induction and plant regeneration from the stage mentioned above were 17.8 and 6.7%, respectively. When calli were cultured on the MS medium containing picloram and zeatin at $25^{\circ}C$, shoots were obtained. Roots of regenerated plantlets were confirmed as haploid through an microscopic observation.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.27-32
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• 1971

In 1969, a pot experiment with four replications of 10 treatments including control(without potash) was carried out in order to study the effect of potash top-dressings in the condition of heavy nitrogen application on rice. The results obtained may be summarized as follows. 1. When potash was applied 70% as basic dressing and 30% as top-dressing at ear-formation stage, a considerable increase of the yield of paddy was obtained as compared to the treatment of the whole amount of potash as basic dressing. 2. The antagonism phenomenon of $K_2O$ contents with N contents in the plants appeared to be severe at the maximum reduction division stage and ear-formation stage is next. 3. $K_2O/N$ ratio gave a positive correlation with the yield components before heading and specially, $K_2O/N$ ratio at heading stage was considerably correlated with ripening percentage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.805-809
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• 1997

The influence of cool temperature occurred during the booting stage in 1993 on quality of rice grain was compared with that in favorable weather of 1994. The mean and minimum air temperatures during the reproductive growth stage at the paddy field of Jinbu Substation, National Crop Experiment Station were 2.2~7.4$^{\circ}C$ and 2.0~8.9$^{\circ}C$ lower respectively in 1993 compared to those of 1994. Grain fertility and brown rice yield were 11.8％ and 0.4t /ha, and 84.3％ and 5.5t /ha in 1993 and 1994, respectively. There was no difference in amylose content between two years. However, protein content of brown rice in 1994 were 1.6％ lower than that of 1993. There was no difference in alkali digestion value of milled rice between two years. Gel consistency of rice flour was 45mm in 1993 and 59mm in 1994. Amylogram characteristics of rice flour produced in 1993 showed lower peak hot, cool, and breakdown viscosities, and higher consistency and setback viscosities. The palatability of cooked rice by sensory panel test was considerably better in 1994 rice than in the rice of cool year.