• Journal of Plant Biotechnology
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• v.30 no.3
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• pp.241-244
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• 2003

Root cluster section culture, showing high efficient Protocorm-like body (PLB) formation capacity, were established in Doritaenopsis hybrids. Three types of root were obtained from excised shoots in 1/2MS medium containing different concentrations of NAA; \circled1normal roots, \circled2multiple roots and \circled3abnormal root clusters. Those were placed on 1/2MS medium supplemented with 0.5 mg/L thidiazuron for PLB regeneration. PLB regeneration rate was greater in root cluster section cultures (77.8%) compare to normal root tip cultures(30%). Number of PLBs regenerated from root cluster sections were counted over 11 per explant (5.3 per normal root tip).High frequency of PLB regeneration was achieved in root cluster section culture. This result can be used as an efficient method for clonal proliferation of Doritaenopsis hybrids.

• Journal of Plant Biology
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• v.36 no.2
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• pp.177-182
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• 1993

The root nodules of Elaeagnus umbellata were coralloid-shape due to repeated dichotomous branching of nodule meristem. The filamentous endophyte with vesicle cluster ranging from 30 ${\mu}{\textrm}{m}$ to 60 ${\mu}{\textrm}{m}$ in diameter was present only in the cortical cells. The isolated endophytes in vitro culture showed typical Frankia morphology, consisting of highly branched hyphae ranging from 0.8 ${\mu}{\textrm}{m}$ to 1.0 ${\mu}{\textrm}{m}$ in diameter, terminal and intrahyphal sporangia varing in shape and size up to 60 ${\mu}{\textrm}{m}$ in length and laminated vesicles. Its infectivity and effectivity were confirmed by induction of nitrogen-fixing root nodules on the inoculated seedlings of two Elaeagnus species. Consequently, the isolate was confirmed as a true symbiont of Elaeagnus umbellata root nodule and named Frankia EuIK1.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.64-67
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• 1994

Crown rot was found find tomatoes growing on a rockwool culture system in a glasshouse at Dongkwangyang in 1992. The disease occurred on the stem of 'Trust' tomato plants with 3~4 cluster of flowers. Infected plants showed stem girdling and necrosis at or slightly above the rockwool line. Internal tissues of crown and stem including cortex, vascular bundle, and pith became decayed resulting in a chocolate-brown discoloration extending no more than 10~15 cm above the crown. Diseased tomato plants with the similar symptoms were found at Ansung and Taejon where tomatoes were grown on either rockwool or soil in plastic greenhouses. The size of macroconidia of Fusarium isolated from a diseased plant was 26.0~41.6$\times$2.9~4.7${\mu}{\textrm}{m}$, and microconidia were formed on short monophialide and the size was 3.6~12.5$\times$2.9~3.6 ${\mu}{\textrm}{m}$. Morphological characteristics and inoculation tests indicated that the causal organism of the disease was Fusarium oxysporum.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.236-242
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• 2003

A culture-independent and -dependent survey of the bacterial community structure in the rhizosphere and soil samples from hot pepper plants was conducted using 16S rDNA clone library and FAME analyses. Out of the 78 clones sequenced, 56% belonged to Proteobacteria, 4% to high G+C Gram- positive group, 3% to Cytophyga-Flexibacter-Bacreroides, and 32% could not be grouped with any known taxonomic division. Among the 127 FAME isolates identified, 66% belonged to low G+C Gram-positive bacteria (Baciilus spp.) and 26% to high G+C Gram-positive bacteria. In a cluster analysis, the results for both methods were found to be strikingly dissimilar. The current study is the first comparative study of FAME and 165 rDNA clonal analyses performed on the same set of soil, rhizosphere soil, and root samples.

• Journal of Environmental Science International
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• v.24 no.2
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• pp.197-205
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• 2015

This study was performed to identify the effect of fertilizer application and planting method on growth and yield of 'Seolhyang' strawberry during seedling raising. According to the concentration of fertilizer applied, the height of daughter plants was the highest at an EC of $0.8dS{\cdot}m^{-1}$. Leaf number and crown diameter were greatest at an EC of $0.6-0.8dS{\cdot}m^{-1}$. In the first measurement, root number was highest in non-fertilizer application, while root weight was heaviest in non-fertilizer application and EC $0.4dS{\cdot}m^{-1}$. The higher the concentration of fertilizer applied as culture media, the lower the growth rate. Thirty days after planting on the main field, plant height and number of new leaf were highest at an EC of $0.8dS{\cdot}m^{-1}$. However, no significant difference was found in leaf length and width and chlorophyll content according to fertilizer application. Marketable yield of 25 g or higher was greatest in EC $0.6dS{\cdot}m^{-1}$. In contrast, no significance was found in total marketable yield at an EC of $0.4-0.8dS{\cdot}m^{-1}$. Aconsistent pattern was exhibited in the growth of 1-5 harvesting flower clusters according to planting method. The length of leaf and flower cluster was short and chlorophyll content was low, when bed soil was removed 100% in harvesting of the first flower cluster. In all treatment, leaf length was shortened until harvesting of the second and third flower cluster, but rapidly lengthened in harvesting of the third and fourth flower clusters. Moreover, the length of flower cluster had a increasing tendency from harvesting of the third flower cluster. However, chlorophyll content was reduced continuously until harvesting of the fifth flower cluster, and was lowest in harvesting of the fourth flower cluster without removal of bed soil. Total yield was greatest in treatment of crown removal in bed soil between November and May. Late marketable yield between March and May was highest in treatment of 100% bed soil removal, followed by treatment of crown removal. Marketable yield of 25 g or higher was greatest in treatment of crown removal between December and February, while greatest in treatment of 100% bed soil removal between March and May.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.783-789
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• 2010

The effective method for heating root-zone during winter season was studied in the aspects of growth, yield and economics for tomato ($Solanum$ $lycopersicum$) in perlite bag culture. There were four root-zone heating treatments: two hours heating from one hour before to one hour after sunrise, four hours from two hours before to two hours after sunrise, 15 hours after sunset, and no heating. The growth characteristics of the upper parts of plants were not significantly different among the treatments, but root volume increased with longer heating of the root zone. The Plant Development Index, using stem diameter and the length between growing tip and the upper flowering truss, showed relation between yield per cluster and growth pattern. The treatment heating for four hours was the most economic in terms of growth and yield of tomato.

• Korean Journal of Pharmacognosy
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• v.1 no.3
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• pp.81-92
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• 1970

So far, the cultivated peony is known to be originated from an indigenous species, Paeonia albiflora $P_{ALLAS}$ var. trichocarpa $B_{UNGE}$ (PAT). In this study, these two species were morphologically examined in the external and internal feature and in the pattern of callus formation by tissue culture. Also, they were compared with another indigenous species, P. japonica $M_{IYABE}$ et $T_{AKEDA}$ var. pilosa $N_{AKAI}$ (PJ), which were regarded as being scarcely related to them. The root of the cultivated peony is massive consisting with several storage roots, each of them is a hypotrophic and fusiform. The root of PAT consists of several storage roots, each of them is branching and slender. And the storage root of PJ is short, bended buried horizontally, protruding a number of corpulent lateral root. The secondary xylem of the cultivated peony is small clusters of vessels and xylem fibres are arranged in scalariform and among these cluster, single vessel is joined, but that of PAT is small clusters of vessels are arranged in separate scalariform but are not connected with each other and that of PJ is vessels and xylem fibers are grouped together in elongated clusters that radiate outward from the center. Protoxylem of the cultivated peony is surrounded by four large metaxylem, but that of PAT and PJ by seven. On the other hand, the callus formation patterns of these peonies were different; the cultivated peony callus is formed in an orderly fashion by the mammalate meristematic cell groups, PAT callus is in disorder by the meristematic cells arranged in linear, and PJ callus is in order by the meristematic cells arranged in linear. By the comparison of three different plants in the anatomical appearance and the callus formation pattern, it is evident that the cultivated peony is not derived from PAT.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.235-244
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• 2004

In this study, we compared the levels of methylotrophic bacterial community diversity in the leaf samples of 19 rice cultivars collected from three regions of Korea. Nineteen pink pigmented isolates showing characteristic growth on methanol were obtained. Physiological and biochemical characters of each isolate were examined according to methods described in Bergey's Manual of Systematic Bacteriology. When phylotypes were defined by performing numerical analysis of 37 characteristics, four distinct clusters were formed. The two reference strains, Methylobacterium extorquens AM1 and Methylobacterium fujisawaense KACC10744 were found to group under cluster IV and cluster III respectively. Cluster I diverged on the basis of nitrate reduction and four isolates showed tolerance upto 0.5 M NaCl concentrations. Two strains in cluster I and III were found to possess methane utilizing properties. Most of the isolates in all the four clusters utilized monosaccharides, disaccharide and polyols as carbon source. When the isolates were subjected for indole-3-acetic acid (IAA) analysis in the presence of L-tryptophan, only 8 isolates exhibited IAA production. In addition, the nitrogen source in the medium was found to influence the IAA production. Addition of $(NH_4)_2SO_4$ in the medium led to a 2 to 30 fold increase in the indole synthesis. However, $KNO_3$, $NH_4NO_3$ and $NH_4Cl$ substitution did not significantly stimulate the synthesis of IAA in the growth medium. Result of gnotobiotic root elongation assay significantly increased roots and shoots lengths, and number of lateral roots, which is mediated by IAA production in the culture medium. The rice seedlings primary roots from seeds treated with methylotrophic isolates were on average 27 to 56% longer than the roots from seeds treated with the uninoculated seeds. In addition, application of different high concentrations of authentic IAA ($400g\;mL^{-1}$) to roots of rice seedlings inhibited root growth. However, the IAA concentration from 10 to $200g\;mL^{-1}$, IAA promoted root growth of rice seedlings. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.418-423
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• 2017

In hydroponics, the nutrient solution is supplied considering the water and nutrient uptake characteristics of crops. However, as the ionic uptake characteristics are changed as a result of the weather conditions or the growth response of the crops, the root zone can not be maintained in optimal condition. In addition, the coir substrate has been used mainly for the tomato cultivation in place of the inorganic substrate, there are few studies on long-term cultivation using coir substrate. Therefore, this study was conducted to investigate the effect of EC level of irrigation solution on tomato growth and inorganic ions of root zone in soilless culture using coir. Coir substrate mixed with 5 : 5 chip and dust was used. EC level of irrigation solution was 1.0, 1.5, 2.0, and $3.0dS{\cdot}m^{-1}$. At the initial stage, $NO_3-N$, P, Ca and Mg in the drainage were lower than the irrigation level at 1.0 and $1.5dS{\cdot}m^{-1}$. However, EC $2.0dS{\cdot}m^{-1}$ or higher, all the ions except P were highly concentrated in the drainage. The average fruit weight was not significantly different between 1.0 and $1.5dS{\cdot}m^{-1}$ until 3th cluster, but from the next cluster, the higher the EC level, the smaller the weight. The number of fruit and yield to 6th cluster was the highest at $1.5dS{\cdot}m^{-1}$. From the next cluster, The yield was decreased with the higher EC level. At the early stage of growth, BER occurred only in EC $3.0dS{\cdot}m^{-1}$, but increased in all treatments with increasing irradiation. The incidence rate of EC $3.0dS{\cdot}m^{-1}$ was higher than that of the lower EC level treatment.

• Horticultural Science & Technology
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• v.29 no.1
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• pp.36-42
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• 2011

This research was conducted to investigate the effects of irrigation quantity in irrigation management system controlled by drainage level sensors for perlite bag culture on the growth and yields of tomatoes during different growth stages. Tomato plants were irrigated with four selected methods; supplying small quantity (~70 mL) during entire growth (S-S), large quantity (~145 mL) during entire growth (L-L), small quantity before harvesting the first cluster fruits and large quantity after harvesting (S-L), and large quantity until harvesting the first cluster fruits and small quantity after harvesting (L-S). The irrigation quantity supplied in each time was gradually adjusted along with the ratios as the tomato crop grew during different growth stages. The growth of the tomato plants was unstable and slow during the entire cropping period when the plant was irrigated by small or large quantities (S-S or L-L). In L-S treatment, the growth phase of the tomato was changed from vegetative to generative growth on the basis of the plant development index when each irrigation quantity was changed. The L-S treatment exhibited the largest root volume and yields with stable drainage ratios. Therefore, the optimum irrigation quantity was determined as 145 mL before harvesting the first cluster fruits and 70 mL after harvesting.