• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.359-364
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• 1999

The effect of Salicylic acid (SA) on the leaf growth, chlorophyll content, photosynthesis, stomatal conductance in Commelina communis L. was investigated. C. communis which was grown in Hoagland solution containing 1 mM SA during 3 weeks resulted in a significant reduction of leaf length, width and area. 1 mM SA reduced about 10% of the leaf area at 1 week and 2 weeks, but inhibited 22% of the leaf area at 3 weeks. SA also showed great effect on the reduction of chlorophyll content. SA reduced 47% and 53% of chlorophyll content each at 2 weeks and 3 weeks when it was compared with the control. Chlorophyll a/b ratio in SA treated sample was increased at 3 weeks representing that SA was sensitive to chlorophyll b. The treatment of SA did not inhibit the activity of PSII＋PSI, PSII and PSI. This result indicates that SA did not show direct effect oil the photosynthetic electron transport activity. However, when C. communis was grown in Hoagland solution containing I mM SA fer long period, SA showed clear inhibition of photosyhthesis in intact leaves. The treatment of SA for 3 weeks showed about 23~65% inhibition of photosynthetic activity at various light intensity (100~1000$\mu$mo1 m­$^2$S­$^1$). Similar effect was found on stomatal conductance. The treatment of SA caused an almost closure of stomata. Similar effects of stomatal conductance at various light intensity indicate a loss of normal control on stomatal mechanism. These results indicate that the effect of SA on photo-synthetic activity was not by SA itself but by indirect metabolic pathway.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.843-859
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• 2017

The JK-1 isolate which was the best producer of indole-3-acetic acid and carotenoid among the 388 strains isolated from 28 wetlands in Jeju, was identified to be Rhodopseudomonas palustirs belongs to a typical group of non sulfur purple bacteria based on 16S sRNA sequencing. This study investigated the effect of different cultural conditions of pH, temperature, agitation, light and aeration on growth, IAA and carotenoid production of photosynthetic bacterium JK-1 for optimization of IAA and carotenoid production. It was found that growth, IAA, carotenoid, and bacteriochlorophyll production with light (3,000~3,500 Lux) and agitation (100 rpm) showed better results than those with dark/static or dark/agitation (100 rpm) in anaerobic conditions. The optimal pH, temperature and agitation speed for cell growth were 7, $30^{\circ}C$, 150 rpm, for IAA production were 9, $30^{\circ}C$, 150rpm and for carotenoid production were 6, $25^{\circ}C$, 50 rpm, cultured for 72 h under anaerobic light, respectively. The growth and IAA production were high in aerobic culture compared with anaerocic culture, whereas carotenoid and bacteriochlorophyll content were decreased extremely in aerobic condition (0.5~1 vvm). Subsequently, the optimal culture conditions for JK-1 were selected with pH 7, $30^{\circ}C$ and 100 rpm under anaerobic light and the effect on plant growth was tested by pot assay. Inoculation of JK-1 with 3% (v/v) level caused increase in shoot and root dry weigh that varied from 20%~58% to 40%~28% in young radish in camparison to uninoculated treatment at 50 days of growth. The study suggests that the JK-1 isolate may serve as efficient biofertilizer inoculants to promote plant growth.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.108-114
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• 1999

This study was conducted to investigate the optimum environment for leaf lettuce (Lactuca sativa L. var. crispa) in a plant factory to increase mass-production efficiency of quality leaf lettuce. Transpiration rate and $CO_2$ assimilation rate were increased with increasing the photosynthetic photon flux density (PPFD). The highest fresh weight and dry weight were observed at the PPFD of 200 and 300 U moi $m^{-2}$ $s^{-l}$, respectively. The optimum aerial environment for the growth and quality of leaf lettuce in the plant factory was determined to be over 200 $\mu$mol $m^{-2}$ $s^{-1}$ for PPFB. Although the interaction between light intensity and nutrient level was not significant, the lettuce growth was the best under electrical conductivity (EC) of 1.8 mS $cm^{-1}$ / at high light intensity (250 $\mu$mol $m^{-2}$ $s^{-1}$ ) and EC of 2.4 mS cm-1 at low light level (150 $\mu$mol $m^{-2}$ $s^{-1}$ ) respectively.y.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.142-147
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• 1993

For the purpose of fixing solar energy and utilizing water wastes from food industries for SCP(single cell protein), 170 strains of photosynthetic bacteria were isolated from 56 samples. Among 170 strains, B-Ps-106 strain was selected as the most suitable strain and identified as a variant or a relation of Rhodopseudomonas sphaeroides and its growth was better under anaerobic light condition than aerobic condition. The optimum conditions of the cell growth of B-Ps-106 were investigated on soybean-curd whey media. The optimum pH for cell growth was $8.5{\sim}9.0$. The optimum temperature was $30^{\circ}C$ and the optimum light density was above $0.72\;cal/cm^2/min$. The most favorable concentration of $K_2HPO_4\;and\;(NH_4)_2SO_4$ was both 0.9 g/l when added to soybean-curd whey media.

• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.266-270
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• 2004

A rose factory type is a system that enables year-round, planned and mass production of high quality cut-rose. Conversion of a conventional system to a rose factory is essential to increase cut-rose export. Controlling root Bone in culled rose production factory is very important for economic and efficient production of rose. This study was conducted to determine optimum root zone temperature of nutrient solution in single-stemmed rose production system. The optimum temperature of the nutrient solution for growth, photosynthetic and transpiration rates for 'Red Velvet' was $15\~20^{\circ}C$. Whereas the optimum temperature for 'Vital' was $10\~15^{\circ}C$. However, growth was almost sloped at $30^{\circ}C$, resulting in concluding the adaptation of 'Vital' to high temperature was poor as compared with 'Red Velvet'.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.42-48
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• 1999

This study was executed to see the effects of Ca : K ratios in me.L$^{-1}$ -0:9, 1.5:7.5, 3:6, 4.5:4.5, 6:3 - in the nutrient solution on the photosynthesis, transpiration, growth and incidence of tipburn in butterhead ‘Omega’and Leaf ‘Grand Rapids’lettuce (Lactuca sativa. L) grown in nutrient film technique(NFT). The photosynthesis of both lettuces showed high in the Ca : K ratios of 3:6 and 4.5:4.5 regardless of species. But stomatal resistance of Grand Rapids was higher than that of Omega. The highest transpiration rate of them was shown in the Ca : K ratio of 3:6. The transpiration rate of developing leaves was lower than that of expanded leaves. It was seemed to have relation with incidence of tipbum in the developing leaves. The nutrient solution treatment without Ca developed less growth than that of other treatments, especially growth and development of apical part were inhibited, so that in the both of them incidence of tipburn appeared 100 percent. The incidence of tipburn in Omega appeared 25 percent in the Ca/K ratio of 1.5:7.5, but Grand Rapids did not show it according to the Ca/K ratio in nutrient solution. The highest growth in two species was also shown in the Ca/K ratio of 3:6 except nutrient solution without Ca. This study suggested that the unbalanced ratio of Ca/K affected Ca transport in two species because of the increase of stomatal resistance and diffusive resistance and the decrease of photosynthesis and transpiration.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.41-45
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• 2001

Transgenic tobacco plants were produced by the transformation of ginseng CAB gene using Agrobacterium tumefaciens LBA4404. The presence of CAB gene in the second generation of transgenic tobacco plant was confirmed by genomic PCR. The photosynthetic ability of transgenic plants was higher than normal tobacco plants and the maximum photosynthetic point of transgenic and normal tobacco plants was 500 $\mu$mol m$^{-2}$ s$^{-1}$ . The photosynthesis of C7, C11, 1, C14 cell lines was higher than normal plants at all the light intensities investigated. The photosynthesis of C2, C11, C14 cell lines in 90% dark condition was higher than normal plants. The chlorophyll contents of transgenic tobacco plants were almost same as normal plants. The % of dry weight, nicotine content, total sugar and nitrogen contents of harvested transgenic tobacco plant leaves were almost same as normal plants.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.252-260
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• 2008

This study was conducted to observe the characteristics of mineral nutrient uptake of single-node cutting rose 'Versilla' and to determine optimal nutrient solution control method for soilless culture of 'Versilla' in a closed hydroponic system. Nutrient solution was managed by five different control methods: macro- and micro-element control in aeroponic system (M&M), macroelement control in aeroponic system (M), nutrient solution supplement in aeroponic system (S); electrical conductivity (EC) control in aeroponic system(EC-A); EC control in deep flow technique system(EC-D). The concentration of $NO_3$-N exceeds optimal range whereas P and Mg decreased at the later stage of plant growth with the EC control method, EC-A and EC-D. The overall mineral nutrient content increased with S. On the other hand the nutrient content at the root environment was maintained optimal with M&M and M. The nutrient solution control methods had significantly effect on the cut-flower quality. In the M&M and M, flower length, fresh weight and root activity were higher than those with the other mineral nutrients control methods. The maximal efficiency of photochemistry (Fv/Fm) was higher for M&M, M and S than that with EC-A and EC-D. Based on the above results, it is highly recommended to control nutrient solution by mineral nutrient control methods (M&M and M) in a closed hydroponic system for single-node cutting rose, 'Versillia'.

• Journal of Bio-Environment Control
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• v.4 no.1
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• pp.25-31
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• 1995

This study was carried out to investigate the effect of the concentration of nutrient solution on the growth of tomato(Lycopersicon esculentum Mill. cv. seokwang) in substrate culture. The substrates used in the experiment were perlite, vermiculite, and peatmoss. Tomato plants were treated with different concentrations of nutrient solution, viz. 0.5, 1.0, 2.0, 3.0, and 5.0mS/cm at seedling stage and transferred to different treatments, 1.0, 2.0, and 3.0mS/cm after transplanting in each substrate. As the concentrations of nutrient solution increased from 0.5 to 3.0mS/cm at seedling stage, the $CO_2$ assimilation rates of seedlings increased in all three substrate culture. Beyond this range, the $CO_2$ assimilation rates of seedlings decreased. By increasing the concentrations of nutrient solution, plant height, leaf length, leaf width, stem diameter, and top dry weight increased in perlite and were high at 2-5mS/cm in vermiculite. On the other hand, in peatmoss, the best result was shown at 3.0mS/cm. Therefore, the adequate concentration of nutrient solution on early growth of seedlings differed among substrates and was shown to be 3.0-5.0mS/cm in perlite, 2.0-5.0mS/cm in vermiculite, and 3.0mS/cm in peatmoss. Generally, as the concentrations of nutrient solution increased from 1.0 to 3.0mS/cm after transplanting, dry weight increased significantly in all three substrate culture. However, dry weights of tomato plants grown under high concentration of 5.0mS/cm slightly increased both at seedling stage and after transplanting.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.189-192
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• 2000

The objective of this study was to investigate the effect of high content of light-absorbing pigments on overall photosynthetic efficiency in high density microalgal cultures. The light harvesting complex II (LHC II) regulating gene of Rhodobacter sphaeroides, photosynthetic purple bacterium, was removed to construct a mutant strain that had less pigment content. The mutant and wild type strains were cultured under various light intensity by adjusting the distance from the light source. The productivity of the mutant strain was higher at high light intensity (over 118 ${\mu}E/m^2/s$) compared with one of the wild type , and was lower at low light intensity (34 ${\mu}E/m^2/s$). Especially, the concentration of LHC II mutant strain was 56% higher at 118 ${\mu}E/m^2/s$. The reduction of per cell pigment contents in the mutant strain lessened the degree of the mutual shading and thus enhanced the overall photosynthetic efficiency.