• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.15-20
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• 1999

To investigate the function of the chloroplast small heat shock protein (small HSP), transgenic tobacco plants (Nicotiana tabacum L., cv. SRI) that show constitutive expression of the chloroplast small HSP were generated. Effects of constitutive expression of the introduced gene on thermotolerance were first probed with the chlorophyll fluorescence. After a 5-min incubation of leaf discs at high temperatures, an increase in the Fo level and a decrease in the Fv level, indications of separation of LHCII from PSII and inactivation of electron transport reactions in PSII, were mitigated by constitutive expression of the small HSP. When tobacco plantlets grown in Petri dishes were incubated at $52^{\circ}C$ for 45 min and subsequently incubated at $25^{\circ}C$, leaf color of nontransformants was gradually became white and all plantlets finally were died. Under conditions in which all nontransformants were dying, more than 80% of the transformants remained green and survived. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery during heat stress.

• Korean Journal of Plant Tissue Culture
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• v.25 no.6
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• pp.477-485
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• 1998

To underatand in vitro regulation of differentiation, the effects of growth regulators and nitrogen source on metabolism of cell wall polysaccharides in suspension culture of kidney bean (Phaseolus vulgaris L.) were investigated. The suspension cells (cell clusters) were directly induced from the epicotyl segments of the seedlings, which were cultivated in MS medium supplemented with 1.0mg/L of 2,4-D and 0.5 mg/L of kinetin. When compared with cell wall sugar contents of the epicotyl segments, the cellulose content of the suspension-cultured cells decreased; while the pectin and hemicellulose content increased; suggesting increases of rhamnogalacturonan I and arabinogalactan IIduring the dedifferentiation, respectively, The effects of growth regulators(2,4-D, 1.0mg/L and kinetin, 0.5mg/L) and nitrogen source (potasium nitrate, 19.0mg/L and ammonium nitrate, 16.5 g/L) in the medium on the proliferation and the turnover of the cell wall polysaccharides were investigated for 30 days. In the medium with growth regulators and without nitrogen source, the proliferation rate was extremely high (16 folds). Growth regulators and nitrogen source increased the pectin content. Analysis of neutral sugar composition of pectin fraction showed that nitrogen source enhanced rhamnose level remarkably, suggesting that rhamnogalacturonan I was the one most likely synthesized. In hemicellulose fraction, growth regulators reduced arabinose level, suggesting that arabinogalactan II was degraded. And nitrogen source reduced galactose level, suggesting that xyloglucan was also degraded.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.266-287
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• 2004

The non infecting, plant associated bacteria have attracted increased attention for stimulating plant growth and as environmental friendly plant protecting agents. Pink-pigmented facultatively methylotrophic bacteria (PPFMs), classified as Methylobacterium spp., are persistent colonizers of plant leaf surfaces. As the leaves of most or all plants harbor PPFMs that utilize leaf methanol as their sole source of carbon and energy, which is a specific attribute of the genus Methylobacterium. Although they are not well known, these bacteria are co-evolved, interacting partners in plant metabolism. This claim is supported, for example, by the following observations: (1) PPFMs are seed-transmitted, (2) PPFMs are frequently found in putatively axenic cell cultures, (3) Low numbers of seed-borne PPFMs correlate with low germinability, (4) Plants with reduced numbers of PPFM show elevated shoot/root ratios, (5) Foliar application of PPFMs to soybean during pod fill enhances seed set and yield, (6) Liverwort tissue in culture requires PPFM-produced vitamin B12 for growth, (7) treated plants to suppress or decrease disease incidence of sheath blight caused by Rhizoctonia solani in rice, and (8) the PPFM inoculation induced number of stomata, chlorophyll concentration and malic acid content, they led to increased photosynthetic activity. Methylobacterium spp. are bacterial symbionts of plants, shown previously to participate in plant metabolism by consuming plant waste products and producing metabolites useful to the plant. There are reports that inform about the beneficial interactions between this group of bacteria and plants. Screening of such kind of bacteria having immense plant growth promoting activities like nitrogen fixation, phytohormone production, alleviating water stress to the plants can be successfully isolated and characterized and integration of such kind of organism in crop production will lead to increased productivity.

• Journal of Bio-Environment Control
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• v.18 no.1
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• pp.46-50
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• 2009

This study was carried to investigate effects of optimum supply strengths of 'Sonneveld' nutrient solution on growth characteristics in container seedling of trees (Pinus densiflora, Torreya nucifera, Quercus acutissina and Fraxinus mandshurica) using developed media with used-rockwool. Flesh weight, height and trunk diameter in container seedling of Torreya nucifera were better in high strengths. In container seed ling of Torreya nucifera, flesh weight more increased in 1.5 and 3.0 strengths and hight and trunk diameter more increased in 1.5 strength than the rest. Flesh weight in container seedling of Quercus acutissina was heaviest in 2.0 strength and was lightest in 1.0 strength. Height and dry weight in 2.0 and 3.0 strengths and trunk diameter and total chlorophyll in 2.0 strength were better than in the rest. Besides photosynthesis rate was more high in 1.5 and 2.0 strengths than in the rest. In container seedling of Fraxinus mandshurica, flesh weight, height and trunk diameter more increased in 0.5 strength and total chlorophyll and photosynthesis rate were good in 0.5 and 2.0 strengths. Most growth characteristics were poor in 3.0 strength.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.192-201
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• 2019

While a fairly large amount of organic matter is produced daily via phytoplankton photosynthesis in Lake Paldang, South Korea, knowledge of the role of algal-derived organic matter (OM) as a refractory OM source is not adequate. To understand the contribution of algal-derived OM to the refractory pool, biodegradation experiment and $KMnO_4$ oxidation experiment were conducted for 60 days using $^{13}C$ and $^{15}N$ labeled natural phytoplankton assemblage. The assemblage was collected from Lake Paldang on May 20, 2010. The photosynthetically produced total organic carbon ($TO^{13}C$), particulate organic carbon ($PO^{13}C$), and particulate nitrogen ($P^{15}N$) remained at 26%, 20%, and 17% of the initial concentrations, respectively, in the form of non-biodegradable organic matter. In addition, 12% and 38% of $PO^{13}C$ remained after $KMnO_4$ treatment on Day 0 and 60, respectively. These results indicate that photosynthetic products could be an important source of refractory organic matter after microbial degradation. Moreover, the microbially transformed algal-derived OM could contribute to the oxidation rate of the chemical oxygen demand.

• Korean Journal of Environmental Biology
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• v.38 no.3
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• pp.404-415
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• 2020

We investigated the seasonal variations in growth and physiological responses of the kelp species Ecklonia cava to different nitrogen sources to establish indoor culture conditions for mass production. Ecklonia cava was cultivated for 10 days in 16 combinations of seawater temperatures (15, 17, 21, and 25℃) and different nitrogen sources (control; NH-NH₄⁺ 100 μM; NO-NO₃^- 100 μM; and NHNO-NH₄⁺ 50 μM+NO₃^- 50 μM). The growth and growth rate of the blade were affected by temperature. The mean fresh weight and area-based daily growth rate were the highest (5.8±0.5 and 6.6±0.5% day^-1, respectively) at 15℃ and the lowest (2.2±0.2 and 3.0±0.3% day^-1, respectively) at 25℃. The daily growth rate was the highest in the NH and NO treatments and lowest in the control. The nitrate reductase activity of E. cava varied with water temperature (season). The highest activity was in the control (1.32±0.10 μmol NO₂^- g^-1 dry weight h^-1) and the lowest was in the NH treatment (0.25±0.02 μmol NO₂^- g^-1 dry weight h^-1). The photosynthetic pigment concentrations reached a maximum value in the NHNO treatment and a minimum value in the control. These results showed that water temperature played an important role in the cultivation of E. cava and that a single supply of NH₄⁺ or NO₃^- may induce the accelerated growth of E. cava. The growth and physiological responses of E. cava to different nitrogen sources during each season provide valuable information for determining the optimal nitrogen source in E. cava cultivation under indoor conditions.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.249-257
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• 2017

Agastache rugosa, is a perennial medicinal plant commonly used in Chinese herbalism, and may have anti-atherogenic and antibacterial properties. Here in this study, we investigated the growth and variations in antioxidant contents of A. rugosa in response to nutrient solution and photosynthetic photon flux density (PPFD) with artificial lighting for a hydroponics culture. Fluorescent light at 150, and $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD with a 16/8 (light/dark) photoperiod, combined with four different nutrient solutions [developed by Horticulture experiment station in Japan (HES), University of Seoul (UOS), Europe vegetable research center (EVR), Otsuka-house 1A (OTS)], were used in a hydroponics culture system for 6 weeks. The shoot and root dry weights of A. rugosa grown with the OTS were significantly higher than those of other nutrient solutions. The amount of tilianin was the highest grown with the OTS, followed by EVR, HES, and UOS. Total acacetin content was the highest in A. rugosa grown under EVR which was statistically similar with OTS. The A. rugosa grown under $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD produced higher fresh weight and both acacetin and tilianin contents than that grown under $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD. The present results suggested that OTS along with $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD could be an optimum growing condition for better growth and higher accumulation of tilianin and acacetin contents in A. rugosa with hydroponic culture systems in a plant factory.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.3
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• pp.185-191
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• 1973

Effects of nitrogen sources on chlorophyll, activity of some oxidases in soybean leaves were investigated in relation to phosphorus sensitivity. Ammonium and urea culture accelerated leaf senescence more in phosphorus sensitive cultivars. The leaf senescence patterns affected by nitrogen sources were clearly indicated by intact leaf absorbance. Absorption maximum (670nm in methanol extraction or 685nm in intact leaf), was not changed by nitrogen source in the same method. According to leaf senesence pattern general physiological sensitivity pattern was discussed. IAA-oxidase activity was higher in the phosphorus tolerant cultivars and nitrate treatment than in the sensitive cultivars and ammonium treatment. Glycolate oxidase activity was higher in the sensitive cultivars and nitrate treatment. Polyphenol oxidase activity was higher in the tolerant cultivars and urea treatment. It is concluded that the excess ammonium, to which excess phosphorus is highly similar in physiological effect, disturbs the photosynthetic system by inhibition of ATP generation (photo-and oxidative phosphorylation).

• KSBB Journal
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• v.20 no.6
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• pp.413-417
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• 2005

The purple sulfur phototrophic bacterium, Thiocapsa roseopersicina NCIB 8347 has been studied on hydrogen production and cell growth under different culture conditions, such as light source, light intensity, and growth temperature. T. roseopersicina showed maximum cell growth of 1.38 and 1.42 g-DCW/L under 7.5-10 klux of halogen and fluorescent light, respectively, and produced maximum amount of hydrogen with values of 0.90 and 0.48 $mL-H_2/mg$-DCW under the irradiation of 10 klux of halogen and fluorescent light, respectively. The optimum growth temperature for hydrogen production was $26^{\circ}C$, and hydrogen production rate was lowered over $30^{\circ}C$. When T. roseopersicina was grown photoheterotrophically under irradiation of 8-9 klux of halogen lamp, the generation time was 4.2 hr. The strains started producing hydrgen from the middle of the logarithmic growth phase and continued until succinate concentration leveled out.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.556-560
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• 1997

The removal efficiency of COD and the production of ${\delta}-aminolevulinic$ acid (ALA) were concurrently investigated for both purifying the soybean curd wastewater of high BOD and utilizing the wastewater as a renewable substrate of ALA production using Rhodobacter capsulatus KK-10. Its wastewater was a favorable media for the growth of photosynthetic bacteria in terms of its environmental characteristics having COD/BOD rate of 0.98, ratio of BOD : N : P=100 : 6 : 4, BOD/N ratio of 17.2, lactic acid of 1,080 ppm. Its COD value wastewater was decreased to 94% and dry cell weight was approached to about 1.2 g/l after cultivation of the photosynthetic bacteria for 4 days. By the addition of 15 mM levulinic acid (LA) into the wastewater at the middle log phase of cell growth, the amount of ALA secreted was 55 mg/l. The ALA production was considerably increased to 114 mg/l under the cultural condition of 15 mM supplementations of glycine and succinate with LA at the same period. Furthermore the maximum ALA production of 120 mg/l and COD removal efficiency of 92% were accomplished in the soybean curd wastewater enriched with one addition of 15 mM LA and three serial additions 15 mM ALA precursors.