• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.59-63
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• 1999

Yield and growth characteristics were compared for five rice cultivars; a new Tongil-type, so called "super-rice", Dasanbyeo, an old Tongil-type Milyang 23, two japonicas Dongjinbyeo and Ilpumbyeo, and a new plant type (NPT)line IR65600-27-1-2. The objective of this stusy was to clarify the high yielding capacity of Dasanbyeo in terms of growth characteristics. The average grain yield (9 t/ha) of Dasanbyeo was higher than that of Milyang 23 by ca. 9% that of japonicas by 20 to 30%, and that of NPT line by ca. 100%. The higher grain yield of Dasanbyeo was attributable not only to the greater dry matter production but also to the higher harvest index (HI). Dasanbyeo showed the greatest dry matter at harvest owing not only to the rapid leaf expan-sion at early growth stage and the resulting high LAI through the entire growth stage but also to the high NAR despite the high LAI. The rapid leaf expansion of Dasanbyeo at early growth stage seemed to be related in part to the profuse tillering capacity. HI was 0.53 in Dasanbyeo, 0,51 in Milyang 23, 0.41 in japonicas, and 0.35 in NPT line. Dasanbyeo was indebted for its higher HI to the relatively high grain filling ratio in spite of a much greater sink size than the other cultivars. Dasan had a greater source to sink ratio during grain ripening as measured by LAD/spikelet and dry matter production/spikelet which showed positove correlations with the grain ripening ratio. New plant type (NPT) line showed the lowest grain yield owing to the small sink size and the low grain filling ratio which seemed to have resulted from the abundant occurrence of weak-strength spikelets. The weak sink strength, in turn, seemed to have suppressed photosynthesis during the grain ripening stage.

• Journal of Korean Society on Water Environment
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• v.38 no.6
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• pp.282-291
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• 2022

Since the efficiency of wastewater treatment using microalgae differs depending on the metabolic characteristics of the species, it is important to understand the characteristics of target algae prior to the application in wastewater treatment. In this study, for the application of Arthrospira platensis to wastewater treatment, which is a filamentous alkaliphilic cyanobacteria, basic species specificity was identified and the possibility of application to wastewater treatment was investigated. As a result of the species specificity investigation, the specific growth rate between pH 7.0 and 11.0 showed the highest value near pH 9 at 0.25/day. The reason for the relatively low growth(0.08/day) at pH 11 was thought to be the CA(carbonic anhydrase) enzyme that is involved in carbon fixation during photosynthesis has the highest activity at pH 8.0 to 9.0, and at pH 11, CA activity was relatively low. In addition, A. platensis showed optimal growth at 400 PPFD(photosynthetic photon flux density) and 30℃, and this means that cyanobacteria such as A. platensis have a larger number of PS-I(photosystem I) than that of PS-II(photosystem II). It was speculated that it was because higher light intensity and temperature were required to sufficiently generate electrons to transfer to PS-I. Regarding the applicability of A. platensis, it was suggested that if a system using the synergistic effect of co-culture of A. platensis and bacteria was developed, a more efficient system would be possible. And different from single cocci, filamentous A. platensis expected to have a positive impact on harvesting, which is very important in the latter part of the wastewater treatment process.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.35-40
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• 1999

$N(^{15}N)$ and $P(^{32}P)$ absorption by 2 year-old Cymbidium Jungfrau in solution culture were investigated. Growth, photosynthesis rate, chlorophyll content and mineral composition of Cymbidium in the solution culture with bark or granular rockwool were compared with these parameters in the conventional pot culture. Nitrogen absorption by Cymbidium was higher in full sunlight than in 60% of sunlight while P absorption was higher in 60% of sunlight. Sixty seven % of N absorbed in plant was redistributed to the bulb(39%) and leaves(28%) while 46% of P absorbed was fund in the bulb (36.2%) and leaves (10.2%). Accumulation of P in leaves was 3-fold lower than that of N. N and P absorption in 0.5 or 1 year- old daughter plant Bowing vigorously were greater than in immature daughter or mother plant. The absorption rate of phosphorus in Cymbidium was 350-fold lower than that of barley. Greater shoot length and bulb diameter, and higher fresh weight, photosynthesis rate and chloroployll content were observed in the solution culture than in the conventional pot culture. Solution culture had-also more content of N, P, K and Mg in leaves, bulb and root than conventional pot culture but did not that of Ca. A large part of the nutrient absorption was occurred during vegetative growth. Also, There was no difference between bark and rockwool in the solution culture due to the improvement of poor dispersion of nutrient solution in bark.

• Journal of Korean Society of Forest Science
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• v.88 no.2
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• pp.249-254
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• 1999

The effects of various levels of Al concentration on growth, nutrient status and net photosynthetic rate of 2-year-old Pinus densiflora Sieb. et Zucc. seedlings grown in a nutrient culture solution were investigated. Al concentrations were added as aluminum chloride($AlCl_3$) at 0(control), 10, 30 and 60ppm to the nutrient culture solution. The nutrient culture solution was maintained at pH 4.0 by adding HCl or NaOH solution. The seedlings were transplanted into the nutrient culture solution and grown in a greenhouse for 90 days from May 8 to August 6, 1996. The treatment above 10ppm of Al concentrations induced a significant reduction on the dry weight growth of the seedlings. The relative growth rate(RGR), net assimilation rate(NAR) and net photosynthetic rate of the seedlings were reduced with increasing of Al concentrations in the nutrient culture solutions. This result suggests that reductions in the RGR and NAR of the seedlings were mainly due to the inhibition of net photosynthesis. In addition, the increase of Al concentrations in a nutrient culture solution decreased the concentration of essential mineral elements such as Ca and Mg in the needle of the seedlings. However, the concentrations of Al of each plant organ increased in the treatment above 10ppm of Al concentrations in the nutrient culture solutions. This result suggests that the increased Al concentration in the belowground part resulted from the decreased concentration of essential mineral elements in the aboveground part of the seedlings.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.44-50
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• 2004

This experiment was conducted to investigate the effects of different levels of light intensity (100, 200, 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$, and natural light) on the growth and the fruit quality of cucumber(Cucumis sativus cv. Hyakunari-3). The results of this experiment indicated that plant height and length of lateral shoots were decreased under low light condition, but it was not significantly different among treatments. Leaf area and root weight were lowest under low light intensity(100 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$), but no significant differences were noted between 200 and 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$. Photosynthesis rate was decreased with reduced light intensity and total chlorophyll contents, root activity and xylem sap were also decreased under low light intensity, but there was no significant difference between 200 and 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$. From the SEM observation the erosion of the guard cells and closed stomata in low light treatment were shown and the size of stoma were small also the stomatal aperture were decreased with reducing the light intensity. Chlorosis in leaves and aborted-liked fruits were appeared under low light condition and Ca and Mg uptake in leaves were decreased by shading in proportion to the decrease of light intensity. Fruit yields were decreased by 65% under 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$, and by 80${\sim}$90% under 200 and 100 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$, compared to those under the natural light. This low intensity of light caused the sharp decrease in the early harvested yields within two weeks and the fruit yields of lateral shoots were greatly decreased.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.432-438
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• 2018

Microalgae hold promise as a renewable energy source for the production of biofuel, as they can convert light energy into chemical energy through photosynthesis. However, cost-efficient harvest of microalgae remains a major challenge to commercial-scale algal biofuel production. We first investigated the potential of electrolytic water as a flocculant for harvesting Tetraselmis sp. Alkaline electrolyzed water (AEW) is produced at the cathode through water electrolysis. It contains mineral ions such as $Na^+$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ that can act as flocculants. The flocculation activity with AEW was evaluated via culture density, AEW concentration, medium pH, settling time, and ionic strength analyses. The flocculation efficiency was 88.7% at 20% AEW (pH 8, 10 min) with a biomass concentration of 2 g/l. The initial biomass concentration and medium pH had significant influences on the flocculation activity of AEW. A viability test of flocculated microalgal cells was conducted using Evans blue stain, and the cells appeared intact. Furthermore, the growth rate of Tetraselmis sp. in recycled flocculation medium was similar to the growth rate in fresh F/2 medium. Our results suggested that AEW flocculation could be a very useful and affordable methodology for fresh biomass harvesting with environmentally friendly easy operation in part of the algal biofuel production process.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.6
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• pp.29-36
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• 2008

This study examined the de-icing agents' stresses on Pinus strobus and Pinus thunbergii by chlorophyll fluorescence analysis. The assumption of this study was that photosynthetic efficiency was changed by de-icing agents applied onto highways in winter by altering the concentration of the de-icier, types of de-icer and leaf surface coating liquid application. The practical purpose of this study was to investigate the de-icing gents stresses on Pinus strobus by the highway area where de-icing agents were used frequently and to discover out minimizing stratages to prevent further damages. or this simulation study, a sample plot was established in Bogae-myeon, Anseong, Gyeonggi-do and Pinus strobus and Pinus thunbergii were planted for the examination in April, 2005. Five types of de-icing agents - NaCl, $CaCl_2$, T product(NS40:low cWoride de-icer type), NaCl+$CaCl_2$ and T product+$CaCl_2$ - were selected and the their concentration was altered to 0%, 5%, and 9%. Five types of de-icing agents were applied to both trees treated by a leaf surface coating liquid and trees not treated by leaf surface coating liquid. For the fluorescence analysis, the leaf surface coating liquid, which was diluted by 10 times, was sprkinkled onto the two tree species three days prior to gathering samples. Sample leaves from the two tree species were gathered at 10 o'clock in the morning of mid-August, 2006 and brought to the laboratory within three hours to be dipped in different concentrations (0%, 5%, or 9%) of the five de-icing agents for two minutes. Then the eaves were placed on the filter paper dipped in each solution on a petri dish, sealed with polyethylene film and kept in a growth chamber at $22^{\circ}C$ for 72 hours. Out of the growth chamber, the leaves were treated with a chorophyll fluorescence reaction analyzer for 30 minutes to measure the initial light acceptance rate(Fo), maximum light acceptance ate(Fv/Fm), light acceptance usage(F' q/F' m) and optical electron delivery coefficient(qP). As a result, Pinus strobus' initial light acceptance rate(Fo) decreased as T product and NaCl increased in concentration, and $Cal_2$ did not reduce much with the eaf surface coating liquid application. Maximum light acceptance rate(Fv/Fm) and light acceptance usage(F' q/F' m) decreased sharply as T product and NaCl increased in concentration and NaCl+$CaCl_2$ and T product+$CaCl_2$ did not reduce much with leaf surface coating liquid application. Optical electrons delivery coefficient (qP) decreased as T product increased in concentration on trees without the leaf surface coating liquid application and all other de-icing agents did not show much reduction. As for Pinus thunbergii, the initial light acceptance rate(Fo) decreased as T product increased in concentration, but the maximum light acceptance rate(Fv/Fm) was not reduced much by changes in concentration. light acceptance usage(F' q/F' m) decreased as NaCl increased in concentration and optical electron delivery coefficient(qP) decreased as NaCl increased in concentration in both with and without leaf surface coating liquid application. In conclusion, it was possible to plant Pinus strobus if spraying leaf surface coating liquid or cleaning deicing salt to prevent the damage caused by deicing agents was more economical than replacing the trees. If not, it was better to plant Pinus thunbergii. Another way to decrease the deicing gents stresses of landscape plants would be planting the trees further away from the roads even though it might take longer period to display its planting functions.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.171-180
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• 2020

The effect of three different light qualities on growth, photosynthesis, quality and safe parameters of hydroponic cultivated spinach (Spinacia oleracea L.) were investigated indoor. Three different light qualities were created of red (660 nm), blue (450 nm) and green (550 nm) LEDs corresponding at ratio R660/B450 = 4/1 (RBL); R660/B450/G550= 5/2/3 (WWL); R660/B450/G550 = 1/1/1 (WL), which were tested at the same intensity (PPFD =190 μmol m^-2 s^-1). The results showed that the plant height and leaf number were the lowest in WL treatment. The SPAD, Net photosynthesis rate Pn, Fv/Fm, Leaf area index LAI values and all parameters of root characteristics were the highest in RBL treatment and were significantly different from two others. Fresh weight of stem, leaf and root, dry weight of root in the three light qualities were significantly different. In contrast, the highest K⁺ content in WL was different from WWL and RBL treatments, while Ca²⁺ and Fe²⁺ content were the highest in the RBL treatment. Vitamin C content was significantly different between the three treatments. nitrate and oxalic acid contents were the highest in WL treatment, whereas soluble-solids contents and vitamin C contents were the highest in RBL treatment. Oxalic acid, nitrate contents were observed tending reduced under WWL although oxalic acid content in RBL treatment was not different from WL and WWL treatments. In all three different light treatments were not detected Salmonella, E.coli. Our results suggest that RBL may be appropriate light for growth of spinach, but supplementary green light to a combination of red and blue LEDs at the reasonable rate can change the quality of spinach in a positive direction. Hydroponic cultivated spinach was safe for users.

• Korean Journal of Environmental Agriculture
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• v.22 no.3
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• pp.185-191
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• 2003

The mechanism imparting salt tolerance to crop plants remains still unsolved, although soybean has been classified as a susceptible plant to NaCl. To determine optimum parameters on physiological responses for improving sensitivity of salinity in breeding program, soybean (Glycine max Merr., cv. "Gwan-gan") plants were grown in a greenhouse, treated 20 days after emergence for 7 days with NaCl at 0, 30, 60, and 90mM, corresponding to electric conductivity of 1.2, 4.4, 7.3, and 10.4 dS/m, respectively, and assessed 30 days after treatment. Chlorophyll contents were significantly decreased by NaCl ($0.4{\sim}1.0\;mg/g$) compared to control (1.2 mg/g). Photosynthesis rate by NaCl treatment at $0{\sim}90\;mM$ at flowering stage was ranged from 5.0 (control) to $9.6\;{\mu}mol/m^2/s$. Oxygen for respiration was consumed from 5.4 to $9.7\;{\mu}mol/m^2/s$ so that the ratio of $O_2$ (evolution:consumption) was increased with the increase of NaCl, indicating that $O_2$ consumption seems to go beyond $O_2$ evolution. Water potential of leaf at vegetative stage II was ranged from -0.6 to -1.8 MPa and the highest level was observed at mid-day. Water potential by salt stress was decreased with range of $-2.1{\sim}-2.7MPa$ compared to control. Transpiration was decreased from 17% to 20% by NaCl stress. Water vapor diffusing resistance of intercellular air space was affected significantly, increasing up to $16{\sim}24%$ compared to control by NaCl treatment. Salt-treated soybean tended to accumulate $Na^+$, specially in root, with reduced absorption of N, P, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ contents. Free proline content of soybean leaf as affected by different NaCl concentrations was increased 4.2 times ($184{\sim}434\;{\mu}g/g$) more than control. NaCl also increased activities of nitrate reductase and peroxidase by $28{\sim}161%$ and $3{\sim}22%$, respectively. The results show that physiological characteristics of soybean plants during assay were useful as the best parameters of salt stress or salt tolerance test to improve sensitivity in screening and breeding program among cultivars or germplasms.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.164-169
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• 2008

This experiment was carried out to find the growth response and changes of nitrate and soluble sugar content in tomato leaves with salt stress. Tomato (Solanum lycopericum) seedlings were grown under different electrical conductivity (EC) levels adjusted with $CaCl_2$ as 1, 2, and $6dS\;m^{-1}$. The growth response and contents of nitrate and soluble sugar in tomato plants were examined at 7 and 14 days after salt treatment. Leaf area and dry weight ratio of shoot to root of tomato plants were decreased as EC level increased. Photosynthetic rate of leaves was reduced under high EC level due to the stomatal closure and the reduction of transpiration rate. The soluble sugar and starch content were lower in the tomato leaves grown under high EC level. Total nitrogen and nitrate contents were decreased in high EC level, whereas the ammonium content was increased. High-salt stress induced the accumulation of salt crystal in mesophyll cells of tomato leaf.