• Food Science and Preservation
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• v.30 no.6
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• pp.969-982
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• 2023

This study evaluated the impact of blanching pak choi stems and leaves in various solutions (distilled water, 2% NaCl, and 2% citric acid) at 100℃ on their quality characteristics. The highest stem heating loss was observed in the sodium chloride solution (S-NB) at 15.10% (p<0.001), and the highest leaf heating loss was in L-NB at 11.44% (p<0.001). No significant variation was found in the moisture content of both stems and leaves. Relative to the control, the L value (lightness) of the stem decreased while the b value (yellowness) increased (p<0.05). In the leaves, the a value (redness/greenness) and b value increased in L-CB, whereas they decreased in other groups (p<0.05). S-NB exhibited the highest true retention (TR) of total polyphenol content (TPC) in stems (p<0.01) and the highest TR of total flavonoid content (TFC) as well (p<0.001). For leaves, the highest TR of TPC and TFC was in L-WB (p<0.001). In terms of antioxidant activity, S-NB in stems and L-WB in leaves showed the highest scavenging activity measured by DPPH and ABTS⁺ assays (p<0.001). Microorganisms were absent in all pretreatment groups but present in the control. The results suggest that blanching pak choi stems in 2% NaCl solution and leaves in water optimally preserves biologically active compounds and nutrients.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.370-376
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• 2012

Disease is the major problem in ginseng cultivation from seed stratification, soil preparation prior to planting, right through to drying of the roots. There are many soil-borne disease pathogen in rhizosphere soil environment, furthermore occurrence of diseases by a diverse group of fungi and related organisms are closely related to various soil condition. Observable symptoms for soil-borne diseases include wilting, leaf death and leaf fall, death of branches and limbs and in severe cases death of the whole plant. The fungus Cylindrocarpon destructans is the cause of root rot characterized by a decay of the true root system in many ginseng production areas in Korea. Some pathogens are generally confined to the juvenile roots whilst others are capable of attacking older parts of the root system. However, the relation between the soil environmental characteristics and ginseng root rot by soil-borne disease pathogen is not clearly identified in ginseng field. In this paper, we reviewed soil-borne plant pathogen causing root rot disease of ginseng with respect to soil environment.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.65-72
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• 2013

This study was conducted to investigate the influences of bicarbonate ($HCO_3^-$) concentrations in irrigation solution on growth of lettuce and change in chemical properties of root media. The blue leaf and red leaf lettuces with two true leaf stages were transplanted into 10 cm diameter plastic pots filled with perlite. The five treatments were made by dissolving $NaHCO_3$ into irrigation solution to reach 30, 70, 110, 150 and $180mg{\cdot}L^{-1}$ $HCO_3^-$. The crops were fed with fertilizer solution contained $HCO_3^-$ with various concentrations and controlled to $100mg{\cdot}L^{-1}$ in nitrogen concentration. The pH in soil solution of root media 10 weeks after transplant of blue lettuces were 7.04 and 7.10 in the treatments of 30 and $70mg{\cdot}L^{-1}$ of $HCO_3^-$, respectively. But those rose gradually after week 3 and finally reached 7.39, 7.48 and 7.56 at week 10 in the treatments of 110, 150 and $180mg{\cdot}L^{-1}\;HCO_3^-$, respectively. The pH in the treatments of 30 and $70mg{\cdot}L^{-1}\;HCO_3^-$ in cultivation of red leaf lettuce were around 6.65 during week 4 to week 8, but this rose abruptly and reached 6.92 and 7.01 at week 10, respectively. Those in the treatments of 110, 150, and $180mg{\cdot}L^{-1}\;HCO_3^-$ rose gradually and finally reached to 7.49, 7.53, and 7.58, respectively. The EC rose gradually after week 2 in all treatments of blue and red leaf lettuces. The change of macro ion concentrations in both blue and red leaf lettuces showed similar trends. The concentrations of $PO_4-P$, $Ca^{2+}$ and $Mg^{2+}$ increased gradually in all treatments of $HCO_3^-$ during cultivation of blue and red leaf lettuces. As the concentrations of $HCO_3^-$ in irrigation solution were elevated, the concentrations of $PO_4-P$, $Ca^{2+}$ and $Mg^{2+}$ became higher and that of ${SO_4}^{-2}$ became lower in soil solution of root media. The main reason of concentration changes were that $HCO_3^-$ influenced pH and the pH changes also affect the activities of the ions in soil solution of root media.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.243-251
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• 2010

Nitric oxide (NO) has been shown to be involved in diverse physiological processes in microbes, animals and plants. In this study, the involvement of NO in the development and possible roles in oxidative stress protection of Chinese cabbage (Brassica rapa subsp. pekinensis cv. Samrack-ulgari) seedlings were investigated. Exogenous application of sodium nitroprusside (SNP) retarded root elongation, while increasing lateral root formation of Chinese cabbage. Plants showed no signs of external stress due to SNP application in true leaves. Cotyledons of 3-week-old Chinese cabbage plants were found to be highly sensitive to SNP application. Treated cotyledons displayed rapid tissue collapse and associated cell death. Although SNP application reduced root growth under normal growth conditions, it also enhanced methyl viologen (MV)-mediated oxidative stress tolerance. Analysis of SNP application to Chinese cabbage leaf disks, revealed SNP-induced tolerance against oxidative stresses by MV and $H_2O_2$, and evidence includes prevention of chlorophyll loss, superoxide anion (${O_2}^-$) accumulation and lipid peroxidation. This report supports a role for nitric oxide in modulating early seedling development, programmed cell death and stress tolerance in Chinese cabbage.

• Journal of Plant Biotechnology
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• v.6 no.3
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• pp.157-163
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• 2004

An efficient system for the regeneration of adventitious shoots from in vitro cultured leaf sections of Lycium chinense Miller was developed and silent somaclones from the regenerants detected with RAPD method. Among the eight media tested (B5, SH, N&N, 1/2MS, MS, 3/2MS, GD and WPM), and four cytokinins (BA, kinetin, 2ip and zeatin) with different concentrations (1, 5, 10, 20, 30 and 40 $\mu{M}$), 1/2 MS medium supplemented with 20 and 30 $\mu{M}$ zeatin showed the best regeneration frequency (100% and 93.7%) and higher average number of shoots (9.0 and 9.4). All regenerants easily elongated after subculturing on 1/4MS without growth stimulants and produced spontaneous adventitious roots from their basal parts. With phenotypically normal 40 regenerants, RAPD analysis with 15 different random primers was performed to examine the cryptic somaclonal variants. No substantial differences in banding patterns were found in the amplified polymorphic DNAs implying no DNA changes during dedifferentiation into adventitious shoots. However, one (OPF-4) of the 15 primers detected silent somaclonal variation in one regenerant in which two different polymorphic bands did not appear when compared with the rest regenerants. The results indicate that regenerantion via intervening callus phase can be used to establish true-to-type planting stocks for homogeneous population.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.1-10
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• 1984

Two fast-growing clones 65-29-19 and 66-6-8 and two less fast-growing clones 66-14-29 and 66-14-99 were compared at intensively cultured plots to identify what morphological characters are related to fast growth and high biomass yield of Populus alba ${\times}$ Populus glandulosa $F_1$. The plantations were established in the spring of 1982 and 1983 at the Seoul National University nursery in Suweon. Differences in dry matter production were found among two-year-old clones but not, among one-year-old clones. Highly significant correlations were found between total leaf area per tree and total dry weight per tree and between total branch length per tree and total dry weight per tree for two-year-old clones. This relation was more obvious during the late growing season. Morphological characters desirable for producing high biomass identified in fast-growing clones were as follows; high shoot-root ratio, high leaf surface area per tree, long leaf retention period, and many small leaves and compact crown architecture in the upper portion of true crown.

• Research in Plant Disease
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• v.19 no.3
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• pp.188-195
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• 2013

This study was carried out for the downy mildew resistant test between 2010 and 2012. A set of 22 accessions belonging to 2 wild species and 20 varieties of the genus Cucumis, originating mainly from the Asian Vegetable Research and Development Center (AVRDC) Gene Centre, was evaluated for resistance to Pseudoperonospora cubensis, causal agent of cucumber downy mildew. The youngest fully expanded true leaves were found suitable for in vitro screening. Both leaf discs and full leaves could be kept fresh longer when applying 0.2 ${\mu}g/ml$ of gibberellin acid (GA). The incubation temperature of $20^{\circ}C$ was found to be the most suitable temperature for symptom development comparing with 15 and $25^{\circ}C$. Symptom development was faster when contact diseased leaf discs (2 weeks after inoculation) on to fresh leaf samples comparing with using conidia suspension ($10^5$ spores/ml). The numbers of spots in 'C-19' were lower than other varieties. 'C-19' variety was also showed the highest level of downy mildew resistant at $20^{\circ}C$ chamber in 6 days after inoculating with pathogen and displayed 0.90 (under 10%) of the infected rate. However, other varieties displayed susceptible in the pathogen sprayed plots. 'C-19' was the most resistant variety and no lesion was observed. Based on all data, 'C-19' can be a useful variety for the prevention of downy mildew.

• Korean Journal of Plant Taxonomy
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• v.41 no.4
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• pp.329-337
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• 2011

The Acer wilsonii complex including A. wilsonii, A. tutcheri, and A. confertifoilum is distributed in southern China. Morphological variation was examined to delimit the species and to determine whether recognition at the specific level was warranted. Univariate and bivariate statistical methods, based on data taken from herbarium specimens, were used to examine morphological variation between and within species. This study showed that A. tutcheri differed from A. wilsonii by its rather short inflorescence, small leaf blades, and three leaf lobes with distinctive serrate leaf lobes. In contrast, there was virtually no separation of taxa with respect to the paniculate-corymbose or short paniculate inflorescence between A. confertifolium and A. tutcheri, suggesting that A. confertifolium morphologically resembled A. tutcheri and is a rather smaller form of it. Circumscription of Acer wilsonii has been quite troublesome, because the important holotype and isotype specimens contained different species under the same number and were misleading with respect to the correct application of the name. Furthermore, lobation is very weak within ser. Sinensia, but diversified inflorescences usually occur in China. A three lobed leaves species, A. wilsonii, represents the reduction in lobation without any modification of panicle inflorescences and seems to be closely related to A. sinense. However, A. tutcheri, which shows a reduction in panicle inflorescence with four petals and sepals, may not be closely related to A. sinense. Three lobed taxa may not correctly reflect the true relationship within ser. Sinensia. The designated lectotype of A. wilsonii, line drawings of representative leaves of related species, a key, and distribution maps of these taxa are presented.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.383-390
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• 2014

This study was conducted to investigate the growth characteristics of cucumber scion and pumpkin rootstock under different levels of light intensity (photosynthetic photon flux, PPF) and plug cell size in a closed transplant production system with artificial lighting. Cucumber scion and pumpkin rootstock seedlings were grown under the combinations of three levels of PPF (PPF 165, 248, and $313{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and five types of plug tray (50, 72, 105, 128, and 200 cells in the tray) for nine days. The shoot dry weight and relative growth rate increased with increasing PPF and plug cell size. As PPF increased, cucumber scion and pumpkin rootstock seedlings had higher dry matter, lower specific leaf area, and lower hypocotyl length. The first true leaf of cucumber scion and pumpkin rootstock unfolded at eight and seven days after sowing, respectively, except the treatment using 200-cell plug tray. The unfolding of first true leaf of seedlings grown in 200-cell plug tray was delayed by one day. Accordingly, it was considered that the use of small cell size such as 200-cell plug tray would require more time for the production of scion and rootstock. Based on the results, we suggest that cucumber scion and pumpkin rootstock be grown in 105-cell to 128-cell plug tray for eight days and 72-cell to 105-cell plug tray for seven days, respectively, when using splice grafting method with root-removed rootstock. Additionally, higher PPF is suggested to improve the growth and quality of scion and rootstock.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.673-683
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• 2014

This study was conducted to establish an efficient screening method to identify cucurbits resistant to powdery mildew. Powdery mildew fungus was obtained from a single lesion of infected cucumber leaf in 2010 at Daejeon. The fungus was identified as Podosphaera xanthii race 1 based on morphological characteristics and resistance responses of four melon differentials. Development of powdery mildew caused by the fungal isolate on 34 commercial cultivars of cucumber was investigated at three plant growth stages in a greenhouse. The degree of resistance of cotyledons of each cultivar to the fungus was not correlated with that of whole plant, but powdery mildew occurrence in the first true leaf was highly correlated with resistance at the level of the whole plant. Based on these results, the first true leaf of cucurbit cultivars can be used for screening of resistance to powdery mildew. In addition, variation of resistance of commercial 12 cucumber and 26 melon cultivars to the powdery mildew fungus due to different growing seasons was tested. In the case of cucumber, the resistance response in some cultivars was influenced by growing season. The resistant cultivars showed higher resistance in the warm season than in the cool season. By contrast, the resistant melon cultivars demonstrated strong resistance in all the tested growing seasons. Interestingly, the tested powdery mildew pathogen, a member of P. xanthii race 1, was not pathogenic on seven cultivars of watermelon (Citrullus lanatus). To follow up on this, diverse race 1 isolates of P. xanthii should be collected and tested.