• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.10a
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• pp.15-20
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• 2005

Locations of silicon accumulation in rice leaves and its possible association with resistance to rice blast were investigated by analytical electron microscopy and atomic force microscopy. A blast-susceptible cultivar, Jinmi, and partially resistant cultivars, Hwaseong and Suwon345, were grown under a hydroponic culture system with modified Yoshida's nutrient solution. Electron-dense silicon layers were frequently found beneath the cuticle in epidermal cell walls of silicon-treated plants. Increasing levels of silicon were detected in the outer regions of epidermal cell walls. Silicon was present mainly in epidermal cell walls, middle lamella, and Intercellular spaces within subepidermal tissues. Furthermore, silicon was prevalent throughout the leaf surface with relatively small deposition on stomatal guard cells in silicon-treated plants. Force-distance curve measurements revealed relative hardness and smaller adhesion force in silicon-treated plants (18.65 uN) than control plants (28.39 uN). Moreover, force modulation microscopy showed higher mean height values of elastic Images In silicon-treated plants(1.26 V) than in control plants (0.44 V), implying the increased leaf hardness by silicon treatment. These results strongly suggest that silicon-induced cell wall fortification of rice leaves may be closely associated with enhanced host resistance to blast.

• Journal of Plant Biology
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• v.30 no.3
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• pp.205-213
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• 1987

Soybean, inoculated with effective Rhizobium japonicum 110, were grown by sand culture with nutrient solution containing either of 0, 1, 3, 10 or 30mM NO3-/l, and analyzed growth characteristics, NR activity, N2-fixation activity, and changes of ureide contents during the growing period. The amount of nodule formation decreased abruptly by nitrate treatment, the maximum nodule dry weight was 1.59, 1.05, 0.78, 0.09 and 0.008 g plant-1, respectively for each treatment on the 98th day. Specfic activity of N2-fixation showed the maximum rates of 140, 101, 37, 5 and 2.2 nM dw.mg-1.hr-1, respectively for each treatment in the earlier growth period. The maximum acetylene reduction activity on the 98th day after sowing was 81.5, 35.3, 14.3, 0.1 and 0.0045 $\mu$M C2H4 plant-1.hr-1, respectively for 0, 1, 3, 10 and 30 mM of NO3- gradients. Nitrate reduction activity increased along with nitrate gradients, and decreased abruptly with age. Relative abundance of ureides in plant organs was high in reproductive growth, and showed the maximum value in fully symbiotic dependent plant. Relative abundance of ureides in stem is a useful indication for the evaluation of nitrogen fixation in nodules of symbiotic plant.

• Journal of Bio-Environment Control
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• v.4 no.1
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• pp.80-88
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• 1995

This survey has been conducted, mostly in inorganic ions, to get some basic data for the culture solution composition, analyzing water quality of some hydroponic farms. pH range was shown from 5.95 to 7.61 and the average of 6.75. Relatively wide range of EC, from 0.07 to 0.97 mS/cm and the average of 0.35 mS/cm were obtained. 19.5 percent of farms investigated showed over 0.5 mS/cm of EC, which means more careful culture solution composition and its management are needed in these farms. Na concentration ranged from 5.0 to 41.4 ppm and Cl concentration ranged from 10 to 99 ppm were shown and their average were 20.38 ppm and 35.16 ppm, respectively. Higher Na concentration compared to standard of 11.5 ppm was shown in 75% of farms and Higher Cl concentration compared to standard of 35.5 ppm was shown in 33.3% of farms. These concentration were considered rather high, which can cause salt accumulation in substrate mats. Ca and Mg concentrations were ranged from 1.60 to 131 ppm and 0.96 to 34.1 ppm, respectively. Average concentrations were 26.11 ppm in Ca and 8.10 ppm in Mg. In case of HCO$_3$, 24 to 295 ppm of concentration range and average of 63.13 ppm were obtained. Fe range was 0.01 to 0.87 ppm and its average was 0.14 ppm. This results showed that Fe elimination was necessary in well water.

• Research in Plant Disease
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• v.12 no.1
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• pp.46-50
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• 2006

The microorganisms with the antifungal activity against Phytophthora capsici and Colletotrichum acutatum and the plant growth-promoting activity were screened from a forest and natural fields of Gajang-Dong, Sangju-city. One of the isolates, Streptomyces griseofuscus 200401, was selected as a good plant growth-promoting strain in this study. In greenhouse test, the number of leaf, fresh weight, and dry weight of pepper plants, that were grown with treatment of culture suspension or powder containing S. griseofuscus 200401, were higher than those without the bacterial cells. Cultivation of S. griseofuscus 200401 strain for 7 days in a nutrient rich medium produced ammonium chloride up to 0.13 ${\mu}g/ml$ in the culture solution of S. griseofuscus. Treatment of the selected strain significantly reduced the severity of the late blight of pepper plants to show the equivalent disease control activity to chemical fungicide. This study suggests that S. griseofuscus 200401 strain could be a potential biological agent with the biocontrol activity and the plant growth-promoting activity.

• Korean Journal of Agricultural Science
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• v.1 no.1
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• pp.35-39
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• 1974

This experiment was studied on the peritoneal fluid wden it was used for nutrient solution of fertilized ova of rabbit when it was cultivated in vitro. The peritoneal fluid also can be gained much from the superovulated rabbits. The results was follow. 1. Wden 2. 4. 8. cell stage ova of rabbit were cultivated in peritoneal fluid in peritoneal fluid at 37'c for 48 Ths, each ova was developed by 78.1, 83.3, 91.7, and 93.6%, and these records were superior to when the blood serum was used. 2. When 2cell stage ova of rabbit was cultivated in peritoneal fluid 88% of Ova were repidly growth Far morula stage and 24 became blastocyst stage these records are nearly same to the records in morulel blood sevium. 3. At these ponts the rabbit peritoneal fluid can be used effectively for on culture fluid.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.80-86
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• 2016

An in vitro trial was conducted to examine the effects of total mixed rations (TMR) on fermentation characteristics and effective degradability (ED) by rumen microbes. Three TMR diets were growing period TMR (GR-TMR, 67% TDN), early fattening period TMR (EF-TMR, 75.4% TDN) and late fattening TMR (LF-TMR, 80% TDN). Three TMR diets (3 g of TMRs in each incubation bottles) was added to the mixed culture solution of stained rumen fluid with artificial saliva (1:1, v/v) and incubated anaerobically for 48 hours at $39^{\circ}C$. The pH in all incubation solutions tended to decrease up to 48h, but the opposite results were found in concentration of total gas production, ammonia-N and total VFA in all incubations.The total gas production (p<0.05) in LF-TMR was highest compared with those of other diets. Also, concentration of total VFA was tended to increase in LF-TMR compared with other TMR diets in all incubations. The EDDM in both EF-TMR and LF-TMR was tended to high compared with GR-TMR (p=0.100). In this in vitro trials, concentration of propionate in all incubation solution was not affected by increased concentration of TDN. The results of the present in vitro study indicate that TMR may provide more favorable condition for nutrient digestion both in the rumen.

• Journal of Bio-Environment Control
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• v.7 no.2
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• pp.151-158
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• 1998

This study was carried out to evaluate the effect of substrates and nutrient solution supplying methods in the media culture using perlite and its mixtures with rice hull, carbonized rice hull. cocopeat on the growth and fruit qualify of hydroponically grown cucumber. Three substrates. Perlite(70%) +rice hull(30%) perlite(70%) +carbonized rice hull(30%) and perlite(70%)＋cocopeat(30%) were compared with perlite medium. Supplying methods of nutrient solution were composed of drip irrigation, modified drip irrigation(covered with cheesecloth between drip hose and substrate) and mist system Leaf area of cucumber Plants was lowest in perlite medium while it was highest in mixture of perlite and cocopeat. NAR was higher in the plot of mixture with cocopeat. and same trend was observed in LAI and CGR. T/R ratio was higher in Perlite and perlite mixture with rice hull. Fruit Yields increased in the plot of modified drip irrigation system. When perlite mixture with rice hull used as a substrate. mist system was recommended. Perlite mixture with carbonized rice hull was observed favored in conventional drip irrigation system. Marketable yield and the number of fruit per plant increased and the malformed fruit decreased in the plot of modified drip irrigation system with the mixtures of Perlite and cocopeat.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.158-165
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• 2019

The effects of microbubbles on glucosinolate accumulation and growth of watercress (Nasturtium officinale R. Br.) were investigated. Watercress plant at the 4th mature leaf stage (2 weeks old) were exposed to microbubbles or non-microbubbles generated in an Otsuka-house nutrient solution for 3 weeks in a controlled environment culture room. Stem length of the watercress grown under the microbubbles was 41% shorter than that of the non-microbubbles, showing significantly different. However, shoot fresh and dry weights, root length, leaf length, leaf width, SPAD, and quentum yield of the watercress were not significantly different between treatments. Glucoiberin, glucobrassicin, gluconapin, gluconasturtiin of the watercress grown under microbubbles, excepted for 4-methoxyglucobrassicin, were significantly higher than those of the watercress grown in non-microbubbles. In addition, watercress grown under microbubbles for 3 weeks contained 85% (${\mu}mol/g$ DW) and 65% (${\mu}mol/plant$) more total glucosinolate, respectively. Results indicated that microbubbles generated in a deep flow technique hydroponics system could increase the accumulation of glucosinolate without growth reduction.

• FLOWER RESEARCH JOURNAL
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• v.17 no.4
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• pp.251-255
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• 2009

This study was conducted to investigate effect of ionic strength and feeding times of a nutrient solution on reduction of stem cavity size and improvement of flower quality in chrysanthemum 'Baekma'. A nutrient solution was applied with different strengths at three stages, namely, transplanting, budding, and flowering. The solution EC was adjusted as 1.61.82.0, 1.81.81.8, 1.82.01.8, and $2.02.02.0dS{\cdot}m^{-1}$ in four treatments. Feeding frequency per a day were 4 times for 12 min., 8 times for 6 min., 12 times for 4 min., and 18 times for 2.7 min. each. Cut flower length as affected by different strengths of a nutrient solution was the greatest in the plot of EC $2.02.02.0dS{\cdot}m^{-1}$. However number of leaves, stem diameter, and leaf size were greater in EC $1.82.01.8dS{\cdot}m^{-1}$ than in other treatments. Also, petal number of petals was the greatest and stem cavity size was the smallest in the plot of EC $1.81.81.8dS{\cdot}m^{-1}$. Plant height, number of leaves, stem diameter, leaf size were greater in the plot with 12 times feed ing per a day. number of petal was most in the plot with 8 times feeding per day, while stem cavity size was the smallest in the plot with 12 times feed ing per a day. Therefore, the better plant growth, the smaller stem cavity size.

• 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.