• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.27-33
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• 2003

The optimal condition of in vitro regeneration and transformation were investigated for newly bred potato varieties in Korea. Leaf and internodal stem tissues of 'Chubak', 'Namsuh', 'Jasim', 'Jopung' and 'Jowon' were used to investigate the influence of growth regulator on regeneration efficiency The effect of phenolic compound acetosyringone on gene transformation efficiency was also investigated. Leaf tissue of 'Jowon' and internodal stem tissues of 'Jopung' were showed high regeneration efficiency on M5 medium supplemented with 0.1 mg/L GA₃, 2.0 mg/L Zeatin and 0.01 mg/L NAA. The other three potato cultivars were showed low regeneration efficiency less than 25%. The effect of acetosyringone on Agrobacterium-mediated gene transformation with leaf and internodal stem tissues were noticeable. By adding the 75 μM of acetosyringone during the Agrobacterium innoculation, the transformation efficiency was increased up to 1.5∼4.0 fold compare to non-treated control. In case of 'Jowon' the transformation efficiency was 87.9% in leaf tissue and 'Jopung' was 68.4% in internodal stem tissues.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.36-41
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• 2001

This experiment was carried out to investigate temperature distribution in the double layer plastic greenhouse and chilling injury to watermelons grown during a cold season. Temperatures on eastern and western sides were about 6.2% and 14.7%, respectively, lower than that of central section in a south-north oriented greenhouse. Daily mean temperature in the northern part was about 1-2$^{\circ}C$ higher than that in the southern part of the greenhouse. In terms of vertical temperature distribution inside the greenhouse, temperature at ground surface was approximately 1$^{\circ}C$ lower during the day and 0.5$^{\circ}C$ higher during the night than that in the upper part, 2m from the ground surface. Leaf mould medium kept higher ground temperatures as compared to sandy soil, red clay soil, and in the northern and southern sides as compared to the central part of the greenhouse. A symptom of chilling injury on leaves was upward curling, followed by chlorosis and necrosis. A severe symptom of chilling injury to plants was the breakdown of vascular bundles. Root growth was more susceptible than stem or leaf growth to low temperatures. At 3$0^{\circ}C$, main and lateral roots grew vigorously, while lateral root growth was inhibited at 22$^{\circ}C$ and root growth was stopped at 14$^{\circ}C$ and 6$^{\circ}C$. Small and puffy fruits with dark green surface were produced at low temperatures. In cold season cultivation of watermelons, it is suggested that plants be transplanted in the central part and train to sides of the greenhouse in order to reduced chilling injuries.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.2
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• pp.63-70
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• 2012

Larix kaempferi and Betula costata seedlings were grown under an elevated temperature ($27^{\circ}C$) for four weeks to understand initial changes on physiological characteristics caused by temperature rising in connection with global warming. At the end of the treatment, growth performance, leaf pigment content, antioxidative enzyme activities and malondialdehyde (MDA) content were measured and analyzed. Relative growth rates of the height of two tree species grown under elevated temperature ($27^{\circ}C$) were lower than those of control ($24^{\circ}C$) and dry weights of leaves, stems and roots were also reduced at higher temperature. Particularly, the root growth reduction of two tree species increased markedly at $27^{\circ}C$ over the study period, which increased the ratio of shoot to root. Under higher temperature, leaf pigment contents decreased, whereas anti-oxidative enzyme activities such as ascorbate peroxidase (APX) and catalase (CAT) increased as compared with the control. But MDA content was not affected by elevated temperature. In conclusion, the elevated temperature leads to root growth reduction, restriction of nutrient uptake from soil and the reduction of leaf pigment contents, which can inhibit the aboveground growth. In addition, higher temperature might act as a stress factor that causes growth reduction through the increase of energy consumption during a growth period.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.410-416
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• 2005

Rhodiola sachalinensis has been used as a traditional medicine in Asia. We were germination in vitro seedling of grow naturally in Chang bai Moutain. And callus induction from leaf segments, treatmented plant regeneration in plant growth regulators (Auxins and cytokinins). We investigated optimal conditions for efficient plant regeneration through callus induction and shoots formation on medium with various kinds of growth regulators. Callus induction and adventitious shoots formation was achieved when cytokinin and auxin combinated to this experiment. Especially, there was the highest callus induction rates when we were used to 1 mg/L kinetin and 2 mg/L NAA $(98\%)$, Adventitious shoots formation wear obtained difference rate when cytokinin alone 1 mg/L BA $(96.6\%)$. And regenerated plantlet was acclimatized and transplanted to the soil, showed $100\%$ survival.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.523-530
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• 2013

This study investigated the influence of seasonal incidence and defoliation degree caused by Marssonina blotch (Diplocarpon mali Harada et Sawamura) on shoot growth and fruit quality of 'Fuji'/M.9 apple tree. The occurrence of marssonina blotch in Gunwi region was observed from the mid of July 2009, and percentage of defoliation was about 10% in the end of October. In 2010, that started in the early of June. By the end of September, percentage of defoliation was 20% and it reached 50% in late October. Secondary growth of terminal shoot in 2010 was three times as much as that in 2009. In 2009, the soluble solid contents and the red color (hunter a value) during fruit maturation increased to $13.8^{\circ}Brix$ and 16.2, respectively. In 2010, the soluble solid content during fruit maturation remained in the $12.1-12.6^{\circ}Brix$ range after early October, and the red color began to increase after the end of September when the percentage of defoliation was 20%. As for fruit quality by defoliation degree, the red color decreased when defoliation percentage of bourse shoot at the end of October was more than 30%. Fruit weight and soluble solids also decreased when defoliation percentage was more than 50%. Fruit length and diameter of over 30% defoliation treatments begun to decrease after the middle of August, compared with those of under 30% defoliation treatment. Photosynthetic rate of the leaves that was located at the secondary growth of bourse shoot was similar to that of leaves which was located at the middle of bourse shoot. However, the size and the soluble solid content of fruit were not affected by photosynthesis activities of bourse shoot leaves which was develop in the secondary shoot growth.

• Journal of Life Science
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• v.21 no.7
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• pp.969-975
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• 2011

We focused on relationship between phytohormones and AtEXPA3 gene in gravitropic response of A. thaliana. RT-PCR analysis shows that AtEXPA3 was highly expressed in actively developing tissues such as leaf, rosette, root and flower tissues. AtEXPA3 gene expression was enhanced by gravistimulation, BR and IAA. Furthermore, decreased gravitropism was observed when treatment of AVG, an ethylene biosynthetic inhibitor, suggesting that ethylene has a gravistimulating effect itself as well as BRs and IAA. Inhibition of gravitropism in AtEXPA3 RNAi mutant suggests that BR, auxin and ethylene are playing roles as regulators of AtEXPA3. In addition, altered gravitropism in BRs signaling mutant (decreased in bri1-301, bak1, and increased BRI-GFP) indicated that BRs signaling mediated the gravitropism. In conclusion, gravitropic responses of Arabidopsis root resulting from root growth were mediated by increased expression of AtEXPA3 gene, which is stimulated by phytohormones.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.548-555
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• 1994

To compare the tolerance of crops to acid rain at different growth stages a simulated acid rain (SAR) of pH 2.7 was applied to rice, soybean, and hot pepper from vegetative growth stage to harvest (Veget.-Harvest) and from reproductive growth stage to harvest (Reprod.-Harvest). Visual damages of crops by SAR were greater in the order of rice < hot pepper < soybean and greater at Veget.-Harvest than at Reprod.-Harvest treatment. Chlorophyll content of all crops was greater in the order of Veget.-Harvest < Reprod.-Harvest treatment < control, but photosynthetic activity was not affected by SAR treatments. Nitrogen concentration and uptake of rice plants at harvest were similar among SAR treatments, but those of soybean and hot pepper were greater at Veget.-Harvest treatment than at Reprod.-Harvest treatment or control. Sulfur concentration of all crops was not affected by SAR treatments, but total sulfur uptake of soybean was greater in SAR treatments than untreated control. Grain yield of rice and soybean was not affected by SAR although grain fertility, percent ripened grains, and 1,000-grain weight of rice at Veget.-Harvest treatment were lower compared with Reprod.-Harvest treatment or control. Fruit dry weight of hot pepper was greater in the order of Veget.-Harvest < Reprod.-Harvest < control due to decreased fruit number per plant and average fruit weight. At one time application of SAR at flowering stage, brown spots were observed on the spikelets of rice at below pH 2.3. Petals of soybean and hot pepper were wilted at pH below 1. 7 and 2.0, respectively, but fruit setting was not affected by the pH of the SRA.

• The Korean Journal of Ecology
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• v.24 no.3
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• pp.157-168
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• 2001

Herbicides have been used to control weeds for decades. If detoxification upon exposure to herbicides requires considerable amounts of energy, it could affect the pattern of resource allocation to growth and reproduction of crops. We examined the effects of three levels of a herbicide (Control, Low, and High) on germination, growth and reproductive characters of Glycine max treated twice, i.e., before and after seed germination. Since flowering time of G. max was separated into two groups, flowering time was also considered as a variable in this study. The rate of seed germination tended to be higher at the low level of herbicide compared to other levels. Chlorosis and shape variation of leaves were apparent after the second herbicide treatment, but completely disappeared after six weeks of treatment. The herbicide effects on growth characters were somewhat different between early and late flowering plants, but plants treated with both low and high levels of herbicide reduced their growth compared to those in the control group regardless of flowering time. Plants at the high level of herbicide exhibited the highest growth rate later in the season, suggesting that plants compensated to some extent for reduced growth. However, growth reduction among plants at the high level of herbicide was persistent until the end of growing season. Among plants flowered late in the season, plants in the control level bore a higher number of nodules per plant than those in other levels; such a pattern did not exist among plants flowered early in the season. Plants treated with low and high levels of herbicide produced a lower number of flowers than those in the control. Thus, the herbicide examined affected not only the growth and reproductive characters of non-target crops but also the development and growth of root nodules.

• Korean Journal of Plant Resources
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• v.34 no.5
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• pp.462-469
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• 2021

Maesa japonica (Thunb.) Moritzi & Zoll. is a rare evergreen shrub that occurs in west Gotjawal, Jeju island, Korea. This study was conducted to investigate effects of an artificial shading on flowering and growth characteristics of M. japonica seedlings. The level of shading had been set to be 35%, 55% and 75% using shading net. The stage of flowering and flowering ratio, seedling height, the number of leaves and stems, leaf area were measured. Flowering timings were delayed by shading. The number of flowering seedlings per plot and inflorescences per seedling were the most in 55% shading level. Tendency of decreased seedling height with increased shading level was shown. The number of leaves and stems were the fewest values in 75% shading level. The increased biomass with decreased shading level was statistically significant. Aboveground and underground biomass were 2.1 and 1.7 times higher in shading 35% than in shading 75%, respectively. Meanwhile, all seedlings in non-shading plots were dead in winter. Such might be speculated as results of the light stress. As a result, we conclude that M. japonica vitally demands the shading for growth and the optimal shading levels for growth and flowering are 35% and 55%, respectively.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.89-94
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• 2000

In order to induce the mutants of Gentiana axillariflora Leveille, nodes were cultured on Schenk and Hilderbrandt (SH) medium containing TDZ 2 mg/L, BAP 2mg/L, GA3 0.5 mg/L and 0.1 mg/L NAA and each mutagen of ethylmethanesulfate (EMS), colchicine, N-methyl-N-nitrosourea (MNU), and sodium azide (NaN$_3$) through filtration. Comparision of morphological characteristics and survival rate in each mutant plants differed depending on mutagen sources and their concentrations. When EMS were treated on nodes, the regenerated plants was thin and albino, regenerated shoots appeared 'erectoides type' and get twisted. The case of colchicine were treated on nodes, the survival rate was from 84% to 97% at ail concentration after 30days but the rate of survival was decreased about 50% at 200 $\mu$M after 60days. The treatment of NaN$_3$200 $\mu$M was not survived. The survival rate was extremely decreased in MNU treatment at 500$\mu$M, according to concentrations two types of leaf characteristic were obtained. Type I of leaf characteristic was modified from oblanceolate to oboid at leaf shape and type II of leaf characteristic was modified from light green to dark violet at leaf color. RAPD analysis was carried out to check the genetic modification of regenerated plants by mutagen treatments. Three polymorphic DNA fragments out of thirty-seven obtained by RAPDs were observed in regenerated plants using 5 decamer primers.