• Horticultural Science & Technology
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• v.31 no.2
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• pp.141-145
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• 2013

The aim of this study was to investigate the effect of two male cultivars of asparagus with low different chilling periods on bud breaking, relative spear growth rate, shoot number and yield. Four-month-old plants of two male cultivars of asparagus were dried to impose dormancy and placed in a coldroom at $5^{\circ}C$ to satisfy the chilling requirement for 0, 2, 4, and 6 weeks. After the specified chilling time, the pots were placed in greenhouse. The results showed that mean days to bud break of 'Jersey Giant' significantly decreased with an increasing chilling period from 0 to 6 weeks, but 'Jersey Supreme' was not affected. The relative spear growth rate of 'Jersey Supreme' was significantly stimulated by chilling compared to non-chilled plants. Shoot production and total spear weight of 'Jersey Supreme' tended to be greater than 'Jersey Giant' irrespective of chilling treatments. Following low temperature treatment, 'Jersey Supreme' showed shorter dormant period than 'Jersey Giant', faster growth of spear. The present study showed that asparagus male cultivar at duration of chilling treatment had an affirmative effect on bud breaking, spear growth rates, shoot number and yield of asparagus.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.99-101
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• 1997

This experiments were conducted to investigate growth regulator concentrations and a period of chilling treatment for increasing the size of bulblets of Narcissus pseudo-narcissus cv King Alfred. Combination of 2.5 mg/L BA and 2.5 mg/L NAA remarkedly increased the diameter and growth of regenerated bulblets. Chilling period favorable for the growth of regenerated bulblets was found to be 8 weeks, and addition of 1.0 mg/L NAA alone to MS medium was the most effective for increasing the size of bulblet for the culture after the chilling treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.257-263
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• 1992

Immature embryos were tested for investigating the effect of cold treatment duration and GA$_3$ concentration on the vernalization response in barley. Immature embryos were cultured on B$_{5}$ medium with GA$_3$ for 5 days, and were transplanted under 20/15$^{\circ}C$ temperature after cold treatment. Germination rate and shoot length were increased more in 20-day-old embryos than those in 13-day-old ones but germination day was decreased. Addition of 1 or 10 ppm of GA$_3$ to B5 medium was effective on the growth of immature embryos. The higher GA$_3$ concentration was, the shorter time from embryo culture to flag leaf emergence and heading was. The earlist flag leaf emergence and heading were showed on treatment of 1 or 10 ppm of GA$_3$, but GA$_3$ did not completely replace vernalization. The days to flag leaf emergence of immature embryo-cultured barley with cold treatment for two and three weeks was shortened by 3 and 18 days at 1 ppm GA$_3$, and 16 and 20 days at 10 ppm GA$_3$, respectively, when compared to 0 ppm GA$_3$ culture with cold treatment for three weeks. It was at 10 ppm GA$_3$ with 3 weeks cold treatment that showed the lowest culm length, spike length and number of grain per spike. GA$_3$ concentration was not correlated significantly with each character in 1 week cold treatment, but was significant with each character in 2 weeks. In 3 weeks cold treatment, it was except for days to heading. Correlation between cold treatment duration and culm length was negative in 0 ppm GA$_3$. In 1 or 10 ppm of GA$_3$, all characters had highly negative correlation with cold treatment duration.n.

• Korean Journal of Medicinal Crop Science
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• v.4 no.2
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• pp.172-177
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• 1996

The influences of testa-removal of seed, partial cutting of embryo, xylene treatment, growth regulator, chemical treatment and low temperature treatment on the seed germination of Lycoris aurea were investigated. The germination rate of the testa-removed seeds was higher than that of the whole seeds, and the seeds treated by testa-removal+xylene was 63% of germination. $GA_3$ was more effective than kinetin treatment, and seeds treated with $GA_3$ 200ppm showed 60% of germination. $KNO_3$ was more effective than KOH treatment, and seeds treated with 0. 1% $KNO_3$ was 76% of germination. The seeds, stored for two months at $5^{\circ}C$, showed the highest germination rate with 93%

• Journal of Bio-Environment Control
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• v.10 no.4
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• pp.244-250
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• 2001

This study was conducted to determine the change in freezing tolerance of Chinese cabbage (Brassica campestris L. ssp. penkinensis). Four-week old seedlings grown in a greenhouse at $25^{\circ}C$$\pm$0.5 were transferred to 5, 10 or 15$^{\circ}C$ condition for acclimation for one day, and then transferred to a lethal temperature of -3$^{\circ}C$ condition. Optimal acclimation temperatures were 5$^{\circ}C$ and 1$0^{\circ}C$. Freezing tolerance of leaf tissues was investigated during a week-long cold stress. Development of freezing tolerance was shown by survival ratio, and amounts of total RNA, soluble protein and soluble sugar. LT$_{50}$ value increased from -3 to -4$^{\circ}C$ after 5 days acclimation at 5 or 1$0^{\circ}C$, and this was considered to be the first indication of enhanced freezing tolerance. Plants, cold acclimated for five days, reached to a survival ratio of 60%. This increase in freezing tolerance was found to be associated with the increased levels of total RNA, soluble sugar and soluble protein. These metabolic changes imply the association of adjustment of growth and cell metabolism with low temperatures at the beginning of cold acclimation in chinese cabbage.e.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.478-483
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• 2017

The expression profiles of low-temperature-related genes were examined in in vitro potatoes exposed to a cold condition for 1-3 days. The expression levels of PPI1 and CI21B genes were lineraly elevated from day 1 to day 3, while the opposite trend was observed for CBF4 and CI21A. In addition, the expression of the genes CI21A and CI21B varied, along with specific tissues (leaf, stem, and tuber) and the treatment periods. Therefore, potato shoot tips were cryopreserved with LS and PVS2 containing different oncentrations of AFP. It can thus be inferred that the presence of AFP in LS and PVS2 was likely to elevate expression pattern of the genes. Furthermore, the concentration of AFP (1,500 ng/ml for LS and 500 ng/mg for PVS2) was the best for the cryopreservation of potatoes.

• FLOWER RESEARCH JOURNAL
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• v.18 no.1
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• pp.44-49
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• 2010

This study was carried out to investigate effect of low temperature and $GA_3$ treatment on flowering and cut flower yield of Limonium spp. 'Ocean Blue' and 'Fantasia' in summer and winter cultivations. Plants were kept at $3^{\circ}C$ for 4 weeks, and were treated with a foliar spray of $400mg{\cdot}L^{-1}$ $GA_3$ at seven weeks after transplanting in both seasons. The effect of low temperature $3^{\circ}C$ for two weeks $GA_3$ application was tested only in winter. In summer cultivation, 'Ocean Blue' and 'Fantasia' of cut flower production by low temperature treatment were increased about 16% and 53%, respectively, while bolting and flowering advanced significantly in 'Ocean Blue' as compared to those in the control. In winter cultivation, growth and development increased, especially, in 'Fantasia'. With low temperature treatment to 'Fantasia' for 4 weeks, cut flower production was increased about 35%. In addition, bolting and flowering were hastened by about 20 and 10 days, respectively. Combined treatment of low temperature and $GA_3$ advanced bolting and flowering with little difference among the cultivars, while, in 'Fantasia' it shortened days to flowering and produced more and best quality flowers as compared to the other treatments and the control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.51-55
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• 1979

The effects of vernalization and darkness on flower initiation were reviewed by using naked barley varieties. The dark effects were pronounced on flower induction even at 25$^{\circ}C$. There were no differences in flowering responses among varieties. The effects of vernalization and darkness combined with 25$^{\circ}C$were 100% and 60% respectively which showed a significant difference. When the alternation of darkness with light was taken as first and last the flowering rate was 92 percent. When it was intercalated by light treatments the flowering rate was 91 per cent. Thus the effects of vernalization and darkness seems to differ.

• Korean Journal of Medicinal Crop Science
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• v.6 no.3
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• pp.210-215
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• 1998

Solomon's seal (Polygonatum odoratum) was traditionally propagated by its rhizomes but seed propagation has not been practiced due to their dormancy and high price. To improve the seedling production through seed pretreatments, the experiment was conducted to determine the effect of seedcoat softening and seed prechilling on seed germination and bulbil formation of the seal. The prechilling was done for 4 to 16 weeks at $3^{\circ}C$ and the softening was forced with 10% KOH for 40 minutes. Seed germination, bulbil formation and length, no. of root and root length were measured at 6 and 12 weeks after sowing. Seed germination and bulbil formation were greater at 8 to 12 week prechilling than at shorter or longer treatment when only the prechilling was enforced. Prechilling had greater effect compared to seed coat softening. In addition, the softening treatment before prechilling showed higher germination and bulbil formation compared to single treatment of them. The softening treatment prior to prechilling was better than the reverse treatment in number of root except the above two characters. Duration of prechilling treatment was able to be shortened below 8 weeks when the softening treatment was applied before prechilling.

• Journal of Life Science
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• v.18 no.12
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• pp.1705-1711
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• 2008

To investigate the relationship between cold stress and the activity of ascorbate peroxidase(APX), dehydroascorbate reductase (DHAR), mRNA expression level of two enzymes, hydrogen peroxide content was studied in lettuce leaves under stress condition imposed by cold stress at $4^{\circ}C$ for 24 hr in the dark and following recovery at $20^{\circ}C$ from cold stress. Hydrogen peroxide content increased gradually in lettuce leaves during cold stress, but decreased slightly following recovery from cold stress. Soluble protein content, however, decreased gradually during cold stress, and then rapidly returned to normal levels following recovery. Total chlorophyll content decreased gradually during cold stress, and then keep constant following recovery. The patterns of chlorophyll a and b content similar to that of total chlorophyll content, and carotenoid content didn't change. The ratio of chlorophyll a and total chlorophyll was increased during cold stress, but decreased with rapid during cold stress, and then the ratio returned to normal levels following recovery. During cold stress, the activity of APX and DHAR in the lettuce leaves increased dramatically, and also transcript levels of mRNA of APX and DHAR, as determined by probing 32P-labeled single stranded RNA of APX and DHAR, highly increased and returned to normal levels following recovery, respectively. Relationship between APX and DHAR activity and hydrogen peroxide highly related ($R^2$=0.8715 and 0.8643), whereas between hydrogen peroxide and total chlorophyll content and soluble content related reversely ($R^2$=0.5021 and 0.8915).