• Journal of Environmental Health Sciences
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• v.16 no.1
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• pp.55-65
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• 1990

This study was carried out to investigate the effects on sister chromatid exchanges (SCEs) and chromosome aberrations in PHA or LPS stimulated mouse spleen and bone marrow lymphocytes after an acute whole body irradiation. Frequencies of sister chromatid exchanges were significantly increased with the increased dose(from zero to 400tad) but there was no differences between B-cell and T-cell. By times, the maximum induced SCE levels was observed at 12 hours after irradiation and then returned to base level at one day in 100rad group and three day in 400rad group. There was a significant difference in chromosome aberration with increasing exposure. X-ray irradiated chromosome aberration was long lived relative to SCE. This results show that counting the incidence of SCE may not provide a sensitive system for detecting X-ray exposure.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.265-275
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• 2017

Selection of double-flowered plants at the seedling stage is one of the main purposes of stock breeding programs. Eight stock cultivars of Matthiola incana L. named 'Nobel', 'Cinderella', 'Pacific', 'Avalanche', 'Midblue', 'Lavender', 'Goddess' and 'Esfahan', with different percentage of double-flowered plants were used for examining the relationship with three morphological types of cotyledons. The results of a chi-square test indicated that in heart-shaped (HC) and cup-shaped cotyledon (CC) populations, the number of plants with double flowers was much more than that of single flowers and CC seedlings rarely produced single flowers. Therefore, increasing the number of CC seedlings can improve the percentage of double flowers. The highest and lowest numbers of CC seedling were observed in high double and single flower cultivars, respectively. Single flower cultivars showed the maximum count of dumbbell-shaped cotyledons. Chromosome pairing of these cultivars was evaluated using the squash technique. Aneuploid cells were found in 'Nobel' and 'Goddess' cultivars, which showed the highest percentage of CC seedling. Based on morphological measurements, the highest value of inflorescence size was observed in the seedlings with cup-shaped cotyledons.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.656-664
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• 2015

To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.900-910
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• 2015

This study aimed to investigate the efficiency of colchicine and oryzalin in inducing polyploidy in two Cymbidium hybrids [Showgirl 'Silky' and Mystery Island 'Silk Road' (Silk Road-4)]. Colchicine was used at concentrations ranging from 50 to $500mg{\cdot}L^{-1}$, with treatments lasting 1 to 3 weeks. Oryzalin was used at concentrations ranging from 3 to $20mg{\cdot}L^{-1}$, with treatments lasting 3 to 6 days or 1 to 3 weeks. The survival rate of PLBs was better in colchicine than in oryzalin solutions. The ploidy levels were screened using flow cytometry. In C. Showgirl 'Silky', the highest chromosome doubling efficiencies were obtained with the 1-week treatment in $50mg{\cdot}L^{-1}$ colchicine (60%) and the 2-week treatment in $5mg{\cdot}L^{-1}$ oryzalin (46.7%). In C. Mystery Island 'Silk Road' (Silk Road-4), the highest chromosome doubling efficiencies were obtained with the 1-week treatment in $50mg{\cdot}L^{-1}$ colchicine (16.7%) and the 3-day treatment in $10mg{\cdot}L^{-1}$ oryzalin (6.7%). Colchicine was more efficient than oryzalin in terms of polyploidy induction. Furthermore, pre-treatment, which entailed poking 10 times with forceps, improved the efficiency of chromosome doubling.

• Fisheries and Aquatic Sciences
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• v.20 no.11
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• pp.29.1-29.7
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• 2017

The objective of this study was to determine a simple and reliable ploidy identification protocol for the rainbow trout (RT), Oncorhynchus mykiss, in the field condition. To evaluate the ploidy level and compare different detection protocols, triploid RT and gynogenesis were induced by UV irradiation and/or heat shock. The hatching rate at day 30 was 85.2% and the survival rate at day 90 was 69.4% (fingerling). The sex ratio of female RT was 93.75% in the gynogenesis group, illustrating that the UV irradiation inactivated the sperm DNA. The hatching rate and survival rate were 82.0 and 74.7%, respectively, in the triploid-induced group. The triploid induction rate by heat shock procedure was 73.9%. Cytogenetic protocols for ploidy identification such as chromosome counting, erythrocyte nuclear size comparison, and analysis of nucleolar organizing regions (NORs) by silver staining were compared. Silver nitrate staining showed the greatest success rate (22/23 and 32/32 for the triploid-induced group and gynogenesis group, respectively), followed by erythrocyte nuclear size comparison (16/23 and 19/32 for the triploid-induced group and gynogenesis group, respectively) and, lastly, chromosome preparation (2/23 and 6/32 for the triploid-induced group and gynogenesis group, respectively) with the lowest success rate. Based on our findings, silver staining for RT ploidy identification is speculated to be highly applicable in a wide range of research conditions, due to its cost-effectiveness and simplicity compared to other numerous ploidy detection protocols.

• Journal of Plant Biology
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• v.17 no.3
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• pp.113-117
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• 1974

In counting chromosome number and karyotype study, it is necessary to let chromosomes on metaphase by pretreatment before fixation. For this purpose, colchicine, or 8-oxyquinoline are generally used. The author found out that chromosomes could be scattered by illuminating cyanoferrate complex solution in which root-tips were sunk. As materials, 8 sorts of plant such as Allium fisturosum, allium tuberosum Rottler, Triticum vulgare were used. Their root-tips were sunk on the bottom of beaker in potassium ferricyanide solution $3{\times}10-4M$ and illuminated through the solution by sterilizing lamp for 1~2 hours in dark room, keeping 10 cm distance from light source to the surface of solution and 2cm depth of solution. Then again, they were illuminated to the light which was somewhat weaker intensity than the former (distance, 16cm; depth, 3cm) for 1.5~2 hours after immersed in 1/100N-HCl and washed in water for each 5minutes. By such methods chromosomes could be scattered. About the mechanism of scattering, it is supposed that CN and Fe(CN)x ions $(x {\leq}5)$ which were gradually produced in the process of photodissociation acted together on the scattering of chromosomes.

• Korean Journal of Plant Tissue Culture
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• v.28 no.4
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• pp.179-184
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• 2001

We evaluated a possibility of the use of chloroplast number per guard cell pairs as a measure for ploidy level in the different ploidy levels of tobacco plant (Nicotiana tabacum L. cv. BY-4) . The guard-cell chloroplast numbers of leaves of haploid plant were a half of wild-type plant. Furthermore, the number of chloroplast per guard cell pairs of the leaves of doubled-haploid plant increased in two times compared with that of haploid plant. In addition, the chloroplast number was not changed in the F$_1$ progenies. The change of the chloroplast number by leaf stage was not observed. The results indicate that there is a strong relationship between ploidy level (2x and 4x) and chloroplast number per guard cell pairs. This relationship was also, observed in both in vitro and pot cultured plants. It was determined that the measurement of chloroplast number in guard cells of leaf epidermis is simple to use and less labour intensive, and hence can be considered a practical alternative to the chromosome counting methods or flow cytometry in the tobacco plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.476-485
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• 1992

M1 plants which were produced from seed soaking in chemical mutagen, EMS or NaN$_3$, appeared wide morphorogical variations such as dwarf, albino, twisted leaf, white streaked leaf, and purpled stem. In mutants of reproductive organs, there were monoecious plants such as female-flower plant and male-flower plant, multiple spikes, and steriled plants among M1 plants. Also, barren stalk was increased significantly in M1 plants. Ear bagging at ear initiation stage prevented seed set on cob in normal plants. In spite of ear bagging, M1 plants which had cobs with seed set was 3.9-11.2% of stalks developed from seeds soaking with mutagens, but only three or four kernels could be matured on a cob. Ear bagging after mutagen injection into initiating ear produced 5.1-10% in cobs with seed set, but only 1.7-6.3 kernels could be matured. Cobs removed silk at four hours after artificial pollination increased the rate of cobs with seed set to 27%. Microscopic observation confirmed that ontogeny of kernels matured from ear bagging and mutagen treatment would be both adventitious and diplosporous apomictic reproduction. Chromosome set of M2 seedling was found to be diploid type in chromosomal counting of root tip. As M$_2$ plants showed an uniform appearence within each lines and their CV of plant height were ranged 4-6% in each lines, we concluded that they were apomictic progeny. But we could not find any marker traits combined with apomixis.