• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.245-252
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• 1993

To investigate a simple and rapid screening method for photosynthetic inhibitory herbicides, responses of tobacco(Nicotiana tabacum L.) and liverwort(Marchantia polymorpha L.) PA(photoautotrophic) cells to various commercial herbicides with different modes of action and leaf extracts of four weed species were compared. PET (photosynthetic electron transport) inhibitory type of herbicides has greater inhibitory effect in liverwort photoautotrophic cells than the photomixotrophic and heterotrophic cultured cells. Similary, PET inhibitory type of herbicides inhibited the oxygen evolution more in liverwort PA cells than the other type of herbicides. Based on oxygen evolution, 60% inhibition was observed by the 10% aqueous extracts of Polygonum hydropiper, while there was 100% inhibition by the 10% methanol extracts of Polygonum hydropiper. This assay gave well correlated results to the Hill reaction data using isolated thylakoids. Thus liverwort photoautotrophic cells might be suitable materials for rapid screening method for photosynthetic inhibitory herbicides.

• Journal of Plant Biology
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• v.36 no.4
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• pp.371-375
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• 1993

$ CO_2$ fixation of isolated intact spinach chloroplasts under saturating light began to decrease after 20 min, and stopped completely after 1 h. To identify the lesion sites for the die off, reconstituted chloroplast system was used with chloroplasts collected at several phases of time course. $ CO_2$ fixation was inhibited in the reconstituted chloroplasts made of thylakoids and stroma in the later phases, but showed a higher degree of inhibition by the participation of thylakoids than that of stroma in the later phases. Measurement of photophosphrylation and NADP reduction revealed that a severed thylakoidal damage was occurred at the later phases. This results indicate that the lesion sites for the die off are in the thylakoid.the thylakoid.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.295-302
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• 1994

For the development of biological wastewater treatment process using photosynthetic bacteria (PSB), photosynthetic sludge process consisted of anaerobic digestion and PSB reactor were designed for the treatment of swine wastewater and the optimal operating conditions in flask-scale were examined. Photosynthetic bacteria from soil, pond, rice field, ditch etc. were isolated in synthetic medium containing high amount of organic acids and finally isolated one strain KK14 which showed the most degradating ability of organic acids was selected for the treatment of swine wastewater. It was identified as Rhodopseudomonas palustris. In the anaerobic digestion stage, the maximum organic acid productivity was obtained at pH 5.0, $37^{\circ}C$, HRT 2 day and under anaerobic standing condition. The optimal operating conditions of PSB reactor for the treatment of swine wastewater were pH 7.0, $30^{\circ}C$ under 4,000 lux illumination, and optimal initial COD loading (kg COD/kg D. C. W of PSB) was 2 (20% v/v seeding) in the main purification stage. Maximum removal rate of COD reached 92% under the above optimal conditions for 5 days.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.177-183
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• 2008

Sodium is known to reduce a plant growth and yields. However, the relationships between physiological response of seedling and salinity stress caused by growing media are not well understood yet. We conducted experiments to investigate change of some parameters including Na, EC, moisture content in media under different air temperature ($15^{\circ}C$, $25^{\circ}C$), and the response of fruit-vegetables such as cucumber, oriental melon on saline conditions originated from horticultural substrate. Volumetric moisture content of media at $15^{\circ}C$ was 70%, but at $25^{\circ}C$ was decreased by 45% within 22 hrs, showing below optimal matric potential, approximately. During reaction time, the increase of Na concentration was significantly greater in saline substrate than in control. The decrease rate of Na concentration according to supplying irrigation water was higher in saline substrate than in control. $CO_2$ assimilation rate and transpiration rate of Korea melon grown in low temperature were decreased with a Na/cation ratio in hydroponic solution. Water saturation deficit was also increased significantly at $15^{\circ}C$ as compare to $25^{\circ}C$. Saline stress during nursery stage induced a reduction of seedling quality, growth and cucumber yield. The results suggest that the relationship between uncontrolled Na uptake of seedling from saline substrate and meteological condition is responsible for saline stress.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.171-175
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• 1994

Physiological changes in Eleocharis kuroguwai Ohwi as affected by bensulfuron-methyl {Methyl 2-[[[[[(4, 6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino] sulfonyl]methyl]benzoate} was determined to relate the characteristics with regrowth behavior. There were no changes in relative growth rate(RGR) during the period of growth cessation after application of bensulfuron-methyl. RGR's of the growth ceseased plants caused at 39 and 51 g/ha began to increase in between 25 and 30 days after application (DAA) and between 30 and 35 DAA, respectively. In untreated plant tuber carbohydrate rapidly decreased right after emergence and almost consumed within 40 days. There was no carbohydrate consumption during the period of growth cessation in bensulfuron-methyl-applied plant, but the content started to rapidly decrease with regrowth. Tuber viability lasted for 30 days in untreated plant, while tubers were viable for 60 and 70 days after application of bensulfuron-methyl at 39 and 51 g/ha, respectively. During the period of growth cessation the plants kept minimum respiration and photosynthesis, but with regrowth respiration and photosynthesis were resumed and rapidly increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.256-260
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• 2008

This study was conducted to response the photosynthetic rate and anatomical characters in one year ginseng plant against the light transmission ratio (10%, 20% and 30% in natural light) under shading materials by polyethylene (PE) net. The chlorophyll content and the photosynthesis of ginseng according to the light transmissivity showed decreasing trend as the light transmission ratio increased. At the higher light transmission ratio condition, leaves showed the chlorosis due to the physiological disorder, stems formed hypodermis, and phloem development inside the vascular tissue shrunk remarkably. Also, roots showed the epidermis destruction and less cambium development at the higher light intensity. The root weight also decreased as the light transmission ratio increased.

• Journal of Bio-Environment Control
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• v.8 no.3
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• pp.192-201
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• 1999

This study was aimed to introduce the measurement of $CO_2$ concentration and leaf area index in the phytotron for predicting the effect of CO.E, light and leaf area index on the instantaneous photosynthetic rate of sweet pepper with the existing ASKAM model. Measurements were made in 2 semi-closed phytotron compartments in which three different $CO_2$ concentrations were applied at random. Plants were grown on containers with circulating nutrient solution at 21$^{\circ}C$ and 80-95% relative humidity. The model estimates crop net $CO_2$ uptake for short time intervals during the day based on short-term data of daily radiation, temperature and $CO_2$ concentration. During the photosynthesis measurements, $CO_2$ concentrations in both compartments and in the basement were measured every minute. This was also done for the flow of pure $CO_2$ into the compartment, global radiation, photosynthetic active radiation inside the compartment, temperature and relative humidity. Crop growth models summarize our knowledge on crop behavior and have as such a wide range of applications in analysis, crop management and thus as a farm management tool.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.508-514
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• 2017

Water-bloom and red tide due to eutrophication have been overgrown and have caused various environmental problems. Recently, however, research on bid-diesel that can utilize algae as an energy source has been actively carried out. In particular, many studies variously have been conducted to utilize algal photosynthesis oxygen as a supply method for reducing the energy by an air blower in MWTP. In this study, a lab scale algae-nitrification reactor was operated to replace the oxygen required for nitrogen removal and the operation period was largely divided into three sections. In the first section, ammonia nitrogen removal efficiency was 24 ~ 38% according to the MLSS (Mixed Liquer Suspended Solid) concentration. In the second section, ammonia nitrogen removal efficiency was 38 ~ 50% according to the micro-algae concentration and in the last section ammonia nitrogen removal efficiency was 61 ~ 80% according to HRT (Hydraulic Retention Time). As a result, as the MLSS decreased and algae biomass increased, the ammonia nitrogen removal efficiency tended to increase, but the effect of Algae biomass was greater than that of MLSS.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.26-29
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• 2003

Experiments were conducted to estimate optimal potassium strength in the nutrient solution for ‘Nokgwang’and‘Kwari’green pepper seedlings cultured in small plug-cell trays. Plant height, stem diameter, and leaf area increased with increasing K concentration, with greater effect on ‘Kwari’ than ‘Nokgwang’. Total dry weight increased by increasing potassium strength.‘Kwari’had heavier dry weight than ‘Nokgwang’Chlorophyll content differed by cultivars and potassium strength. The highest chlorophyll content was obtained at 2.0 strength potassium in‘Nokgwang’, but not in‘Kwari’Net photosynthesis was greater in plants fertilized with 1.5 strength potassium for‘Nokgwang’and 2.0 strength potassium for ‘Kwari’than the other treatments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.226-230
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• 1986

Two near-isogenic lines with dark and pale green leaves, derived from the F$\_$7/ generation of wxl26 cross were compared on photosynthetic capacity, growth parameters, grain yield and yield-related characters. Dark green-leaved lines contained much greater content of chlorophyll a and b than pale green-leaved ones, but chlorophyll a to b ratio showed no difference between them. The photosynthetic nte per unit leaf area was higher in dark green-leaved lines than in pale green-leaved ones in the flag leaves at heading stage, but that per unit chlorophyll content showed reversed result. The crop growth rate from transplanting to heading was consistantly higher in the dark green-leaved lines, resulting from their greater net assimilation rate. Dark green-leaved lines produced greater number of panicles and spikelets per hill, out yielding pale green-leaved lines, but ripened grain ratio and 1000-grain weight showed no differences between those lines.