• Korean Journal of Agricultural Science
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• v.7 no.1
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• pp.1-5
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• 1980

In order to evaluate cold tolerance and to counter measure the cold damage of newly released rice varieties, the effects of degree and duration of low temperature at the meiotic stage on the sterility and ripening of rice spikelets were investigated and the results were as follows: 1. As the temperature was lowered and the duration of low temperature was extended during the meiotic stage, the heading dates were delayed and the sterility were increased. The main factor for the low yield due to low temperature was due to the increased sterility, and under the below $15^{\circ}C$, the delayed heading was also responsible for the low yield. 2. The sterility and delayed kernel development of rice were increased when grown at $15^{\circ}C$ for six days. 3. The newly released rice varieties were highly sensitive te low temperature damage during the meiotic stage. The treatment of rice at $15^{\circ}C$ for four days might be used as a perameter to evaluate the low temperature tolerance of rice varieties.

• Journal of Korean Society of Forest Science
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• v.45 no.1
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• pp.51-61
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• 1979

The chromosome behavior and it's synapsis in the meiosis of pollen mother cell were studied on Populus alba L. as a female parent tree, Populus glandulosa Uyeki as a male parent tree and their hybrid, Populus alba x glandulosa. 1. At metaphase I, the number of nuclear plates with early separation chromosome were observed with the lowest proportion of 11.0% in Populus glandulosa and with the highest proportion of 13.0% in Populus alba${\times}$glandulosa. 2. At metaphase II, early separation chromosomes appeared with the frequency of 11.0% in Populus alba${\times}$glandulosa. But the frequency was not different with those of the parental trees. 3. At anaphase I, lagging chromosomes appeared with some high rate of 11.6% in Populus alba${\times}$glandulosa and yet the number of chromosome bridges in populus alba x glandulosa almost were not different with the partental trees. 4. At anaphase II, lagging chromosomes appeared with some high frequency of 10.2% in Populus alba${\times}$glandulosa and the chromosome bridges in Populus glandulosa appeared with the highest frequency in all studied trees. 5. The frequency of abnormal pollen sporad was the highest value of 8.2% in Populus alba${\times}$glandulosa among the studied trees. With the results, it might be assured that the chromosome segregation and it's synapsis behaved normally in Populus alba, Populus glandulosa and Populus alba x glandulosa, and so all the studied trees could produced normal pollens.

• Applied Microscopy
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• v.34 no.1
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• pp.71-81
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• 2004

When U. unicinctus mature oocytes were fertilized in vitro, germinal vesicle breakdown (GVBD) and meioses occurred and the zygotes entered cleavage stage. A modified pattern of spiral cleavages, suggestively based on behavior of mitotic spindles, have been observed in this work. The first and second cleavages were meridional and the third was equatorial, and then followed by repetitions of meridional-equatorial cleavage. The cleavage of the isolecithal egg were equal and holoblastic and its patterns were spiral. The anti-${\alpha}-,-{\beta}$- tubulin reactions and confocal microscopy revealed mitotic apparates tilted obliquely at each mitosis causing oblique displacements of the blastomeres. Despite isolecithal distribution of yolk, this observations implicated that tilting of mitotic apparates induced spiral cleavage and the displacements of blastomeres. However, these features would not be the typical spiral cleavage, but represented a modified pattern of known Spiralian s in the sense of the equal cleavage. During the first cleavage, heart-shaped eggs have been produced. Electron microscopies exhibited the first cleavage furrow extended with its membranous structure deeply into the cytoplasm. Contractile ring has not been observed.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.659-666
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• 2022

The effect of rye B chromosome (rye B) on chromosome association was investigated in meiosis of wheat addition line. The wheat addition line was with one Leymus mollis chromosome and one L. racemosus chromosome which are under homoeologous relationship. Chromosome behavior of the two Leymus chromosomes in wheat genetic background was revealed by genomic in situ hybridization. In the first metaphase, most of the two Leymus chromosomes showed univalent in the wheat addition line without rye B (98.1 ± 0.5%). On the other hand, the wheat addition line with rye B showed higher frequency of bivalent (10.3 ± 0.2%) than wheat addition line without rye B (1.9 ± 0.5%). The wheat addition line without rye B showed abnormal bivalents with abnormal structure while the wheat addition line with rye B showed normal bivalent in low frequency. By rye B, some bivalent was composed of wheat and L. racemosus, and some trivalent was composed of wheat bivalents with L. mollis chromosome. Also, some wheat bivalents showed hyper-crossover, so those wheat bivalents showed abnormal structure compared to other wheat bivalents with normal structure such as ring, rod, and pan.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.1
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• pp.41-57
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• 1983

The effect of temperature 'during the reduction division stage on the Indica-Japonica rice varieties were studied in artificial temperature-controlled cabinets (Bioclimatic Laboratory). Varieties used were indica-japonica crosses (Suweon 264, Suweon 258, Milyang 29), indica (IR36, Lengkwang) and japonica rice (Jin-heung). The results obtained from this study are summarized as follows. The most sensitive stage to low temperature, the tetrad stage, was observed in each variety with the following auricle distance: Jinheung, -12cm; IR36, -3cm; Suweon264, -9cm; Suweon258, -3cm; Milyang29, -6cm and Lengkwang, +1cm. The tetrad stage occured when the palea elongation was about 50 to 60% of the final palea length at flowering stage in all varieties. The percentage of degenerated spikelets at tetrad as influenced by low-temperature treatment was very low in Jinheung and Lengkwang, but very high in IR36. In indica-japonica crosses only the 7-days treatments had a very high percentage. Between the 4-day and 7-day treatments as well as among all varieties, clear differences were observed in the low temperature induced sterility of 'special spikelets' (upper position grains at tetrad). In the 7-day treatments except in Lengkwang, all varieties showed very high sterility. It appears that the treatments is over the critical limit for treatment. However in the 4-day treatments, the intervarietal differences in sterility were very clear. In Jinheung, sterility was 46.8%; IR36, 67.6%; Suweon264, 60.9%, Milyang29, 62.2%; Lengkwang, 27.8%. A close relationship was observed between fertility and auricle distance. The lowest fertility of special spikelets was at the tetrad stage and the first contraction phase. Before and after the stage there was an increase in fertility. The palea length elongated nearly in a straight line from the spikelet formation stage to flowering. And there was a high correlation between palea length and auricle distance. distance.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.1
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• pp.39-45
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• 1984

The effects of foliar application of phosphate was investigated in the light of plant physiological point of view. The phosphate applied on the foliar both in meiosis and heading time was penetrated considerably into the rice. The amount of P absorbed by foliar application at high temperature was higher than that at low temperature but still considerable amount of P was absorbed at low temperature. The phosphate applied on younger flag leaf was absorbed more vigorously than the second and third leaves. The absorbed P on leaf was translocated to the panicle, especially on the brown rice starch, then moved to another panicle wherever the phosphate was needed. The major fraction of absorbed P under high temperature condition was T.C.A. soluble-Ba insoluble phosphate of mainly phytic form but Ba soluble-EtOH insoluble fraction, sugar phosphate ester, was identified as dominant P under low temperature condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.2
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• pp.203-210
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• 1976

To abtain basic information in process developing cold tolerance rice variety, used 8 varieties which are the close crossing and the remote crossing in order to clarify how is being the differences of low temperature injury in same variety and the varietal difference at each growth stage under the low temperature treatment, 18$^{\circ}C$-12$^{\circ}C$ (day-night), and to establish the effective testing method for low temperature injury in rice plant. In this experiment, the varietal ifferences of low temperature injury were significant in rice plant, and found out that low temperature injury at the each growth stage from sowing to heading in same variety was not horizontal.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.195-200
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• 1990

These experiments were conducted to determine the effect of high temperature and water managements on growth and yield of rice. Shoot dry weight and percent of fresh roots were decreased when rice plant was exposed to high temperature, and also high temperature treatment decreased yield components of rice through spikelet number at meiotic, filled grain ratio and percent of fertility at heading, and 1,000 grain weight at ripening stage. Nitragen content of the rice varities was decreased by high temperature treatment regardless different growth stage, although Si content increased. Grain yield of rice varieties significantly decreased due to high temperature when rice plants were treated at heading stage followed by ripening stage. meiotic, young panicle initiation, maximum tillering and tillering stage in order. Effect of the continual submerging on temperature increased by 1.1$^{\circ}C$ at daytime and by 3.7$^{\circ}C$ at nighttime, but flowing water irrigation which can maintain optimum temperature reduced plant height and increased dry weight and percent of fresh roots. Flowing water irrigation showed higher yield by 4-8% compared to continual submerging method through increment of yield components such as spikelet number, filled grain ratio and 1,000-grain weight.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.1
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• pp.32-40
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• 2003

To characterize diel pattern of methane transport via rice plant, methane emission was measured on specific days in rice growing stages; tillering, meiotic, heading and harvest stages, from a paddy under different water management and organic amendments. Methane emission was monitored every two hours a day from chambers with and without rice plants. Proportion of the rice plant-mediated methane emission at different stage increased till the maximum growth of LAI and dry weight, and decreased thereafter. The proportion of methane emission through rice plants on June 18-19 at tillering stage was 38.4, 36.5 and 64.3 percent for NPK, Rice straw compost, RSC, and rice straw on February, RS2, respectively. The proportion on July 30-31 at meiotic stage was 70.4, 74.3 and 74.4 percent for NPK, RSC and RS2, respectively. The proportion on August 20-21 at heading stage was 80.1, 84.5 and 74.8 percent for NPK, RSC and RS2, respectively. The proportion on September 28-29 at harvest stage was 69.9, 65.9 and 64.4 percent for NPK, RSC and RS2, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.3
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• pp.297-302
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• 2006

We investigated gonadal development and sex ratio of artificial seedlings of the oblong rockfish Sebastes oblongus, based on samplings for 370 days just after parturition. The primordial germ cells and genital ridge appeared separately under the mesentery in the yolk-sac stage larva (total length: 7.10-7.77 mm) just after parturition. The primordial germ cells and genital ridge integrated to form primordial gonad in 5-day-old larvae (7.12-9.68 mm), and then proliferation of somatic cell and germ cell occurred in the gonad, which was maintained undifferentiated until 45-days after parturition (18.6-20.4 mm). The ovarian differentiation began in the larva of 50-days old (dab) after parturition (dap) (20.0-24.5 mm). The somatic tissues elongated from the both opposite end-sites of undifferentiated gonad were consequently fused and formed a complete ovarian cavity at 60-days old dap (25.5-32.0 mm). In 80-days old dap (37.3-47.2 mm), meiosis of oogonia occurred to be chromatin nucleolus stage oocyte. The perinucleolus stage oocytes appeared at in 130-days old dap (68.0-86.0 mm), and previtellogenic stage oocytes appeared in 370-days old dap (101.0-116.0 mm). Only female was observed in the artificially produced oblong rockfish in the present study. This result revealed the effect of higher temperature on the sex determination of the oblong rockfish..