• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.257-264
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• 2006

In order to evaluate the application of Algae Online Analyzer (AOA), an instrument of automatic measurement of chlorophyll a concentration, was tested and compared with the acetone extraction method on the basis of microscopic counting of phytoplankton in field water (Paltang Reservoir). We simultaneously conducted AOA operation and extraction method with the same water sample, to compare both results of chlorophyll a measurement. Phytoplankton were enumerated by inverted microscope with the Sedgwick-Rafter chamber, and classified into the genus or species. According to the AOA measurement, the diatom most (83.6%) strongly contributed to the total chlorophyll a concentration, followed by chlorophyceae> cyanophyceae>cryptophyceae. Overall, the results of both AOA and extraction method showed a similar trend and significant correlation (r=0.87, n=302, p<0.001), however, there were some differences according to the season and species. In particular, the relationship between AOA Chl-a density of the diatom (r=0.73, p=0.010) and cyrptophyceae (.=0.83, p=0.00154) were siginificant, while chlorophyceae (r= -0.13) and cyanophyceae (r= -0.16) showed no clear relationship during the study period. Although we can not fully understand why there was difference between both mothods, AOA application for alarming algal bloom and water quality management during the algal bloom appears to be very relevant. However, the further study or technical upgrade of AOA measurement is required, especially in the case of low density of phytoplankton or species-specific measurement.

• Journal of Life Science
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• v.18 no.12
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• pp.1705-1711
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• 2008

To investigate the relationship between cold stress and the activity of ascorbate peroxidase(APX), dehydroascorbate reductase (DHAR), mRNA expression level of two enzymes, hydrogen peroxide content was studied in lettuce leaves under stress condition imposed by cold stress at $4^{\circ}C$ for 24 hr in the dark and following recovery at $20^{\circ}C$ from cold stress. Hydrogen peroxide content increased gradually in lettuce leaves during cold stress, but decreased slightly following recovery from cold stress. Soluble protein content, however, decreased gradually during cold stress, and then rapidly returned to normal levels following recovery. Total chlorophyll content decreased gradually during cold stress, and then keep constant following recovery. The patterns of chlorophyll a and b content similar to that of total chlorophyll content, and carotenoid content didn't change. The ratio of chlorophyll a and total chlorophyll was increased during cold stress, but decreased with rapid during cold stress, and then the ratio returned to normal levels following recovery. During cold stress, the activity of APX and DHAR in the lettuce leaves increased dramatically, and also transcript levels of mRNA of APX and DHAR, as determined by probing 32P-labeled single stranded RNA of APX and DHAR, highly increased and returned to normal levels following recovery, respectively. Relationship between APX and DHAR activity and hydrogen peroxide highly related ($R^2$=0.8715 and 0.8643), whereas between hydrogen peroxide and total chlorophyll content and soluble content related reversely ($R^2$=0.5021 and 0.8915).

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.85-91
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• 2001

To find diagnosing method of nitrogen status in tomato plant for determining optimum application rate of side dress, chlorophyll reading values were measured by portable chlorophyll meter(SPAD 502, Minolta), and compared with nitrogen supplying capability of soils. Regression between dry weight, amount of nitrogen uptake, and chlorophyll reading at stalk positions of tomato grown on the condition of no fertilization were evaluated For 6 green house soils with different nitrate concentrations ranged from $55mg\;kg^{-1}$ to $306mg\;kg^{-1}$. The chlorophyll reading of tomato leave was significantly correlated with amount of nitrogen per unit area of leave suggesting that chlorophyll content is useful for nitrogen diagnosis of tomato plant. The chlorophyll reading showed peak at the 15th leaf of stalk position on the 45th days after transplanting and this suggested that below or near the 15th leaf and before or near the 45th days after transplanting is the critical stalk position and time for diagnosing nitrogen status of tomato by chlorophyll test. The chlorophyll reading at the 14th leaf on the 40th days after transplanting was significantly correlated with soil nitrate status, dry weight and amount of nitrogen uptake by tomato grown with no fertilization. From the above correlation, the chlorophyll reading value of 57.1 at the 14th leaf of tomato was estimated as the critical level for maximum dry weight and amount of nitrogen uptake by tomato grown with no fertilization. Consequently, chlorophyll reading of tomato leaves measured by portable chlorophyll meter was thought to be available as a rapid plant test for predicting the nitrogen supplying capability of green house soils.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.3
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• pp.181-197
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• 2024

This study evaluated the salt tolerance of Italian ryegrass varieties under various salt stress conditions. Seven varieties, including Kowineary, Greencall, Greenfarm, Greenfarm 3, IR 603, IR 605, and IR 901, were used in this experiment. Under various salt concentrations, there was no significant decrease compared to the control at salt concentrations of 0.1% to 0.3%. IR 901, Kowineary, and IR 605 had a lower relative reduction rate, but the absolute growth of IR 603 was the highest among the varieties. Among chlorophyll fluorescence parameters, ABS/RC, TRo/RC, ETo/RC, and DIo/RC values (activities expressed per reaction center) showed a significantly negative correlation with growth rates. In the experiment where the salt concentration was drastically increased, the growth decreases in Greenfarm 3 and IR 901 were relatively small compared to other varieties. Among the relative ratio of chlorophyll fluorescence parameters, ABS/RC, TRo/RC, ETo/RC (after 1 hour of salt concentration increase), and PIABS (3 hours, 7 days) showed a significant positive correlation, and DIo/RC (3 hours, 1 day) showed a negative correlation with plant growth. In the experiment where the salt concentration was drastically decreased, the growth increases in Greenfarm, IR 901, and Kowineary were relatively high compared to other varieties. Among the relative ratio of chlorophyll fluorescence parameters, ABS/RC, ETo/RC, DIo/RC (5 hours), and PIABS (1 hour) showed a significant positive correlation with plant growth. In summary, among the seven varieties, Kowineary and IR 901 had superior relative growth (compared to the control) under various salt stress conditions. IR 603 showed a greater decrease in relative growth but had the highest absolute growth amount under salt stress conditions. In addition, some parameters related to chlorophyll fluorescence showed a significant correlation with early growth, which could be used as indicators of the initial growth of IRG under salt stress.

• Journal of Ginseng Research
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• v.12 no.1
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• pp.30-39
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• 1988

This study was conducted to investigate the effects of light intensity and temperature on the physiological characteristics and growth of ginseng leaves. The higher the transmittance of the shade, the greater the area was decreased. In contrast, however, the amount of transpiration was increased. There was no significant difference in the number of stomata, but the size of stomata was distinctively decreased. The higher the transmittance of the shade, the more the contents of total chlorophyll, chlorophyll a and b, and cartooned were decreased. In contrast, however, the aye ratio of chlorophyll was increased. Regardless of temperature, the contents of chlorophyll providing maximum photosynthesis at the end of June and August were 2.1mg and 1 8mg/g F.W. respectively.

• Korean Journal of Remote Sensing
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• v.26 no.2
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• pp.189-207
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• 2010

Several ocean color algorithms have been developed for GOCI (Geostationary Ocean Color Imager) using in-situ bio-optical data sets. These data sets collected around the Korean Peninsula between 1998 and 2009 include chlorophyll-a concentration (Chl-a), suspended sediment concentration (SS), absorption coefficient of dissolved organic matter ($a_{dom}$), and remote sensing reflectance ($R_{rs}$) obtained from 1348 points. The GOCI Chl-a algorithm was developed using a 4-band remote sensing reflectance ratio that account for the influence of suspended sediment and dissolved organic matter. The GOCI Chl-a algorithm reproduced in-situ chlorophyll concentration better than the other algorithms. In the SeaWiFS images, this algorithm reduced an average error of 46 % in chlorophyll concentration retrieved by standard chlorophyll algorithms of SeaWiFS. For the GOCI SS algorithm, a single band was used (Ahn et al., 2001) instead of a band ratio that is commonly used in chlorophyll algorithms. The GOCI $a_{dom}$ algorithm was derived from the relationship between remote sensing reflectance band ratio ($R_{rs}(412)/R_{rs}(555)$) and $a_{dom}(\lambda)$). The GOCI Chl-a fluorescence and GOCI red tide algorithms were developed by Ahn and Shanmugam (2007) and Ahn and Shanmugam (2006), respectively. If the launch of GOCI in June 2010 is successful, then the developed algorithms will be analyzed in the GOCI CAL/VAL processes, and improved by incorporating more data sets of the ocean optical properties data that will be obtained from waters around the Korean Peninsula.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.213-226
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• 2004

The present study was conducted to analyze the pattern of eutrophication of Korean reservoir with Chl. a concentration and morpho-physical parameters, and to valuate water quality characteristics of the classified types. The collected data from 486 reservoirs were classified as four types, with the Chl- a concentration (25 ${\mu}g\;L^{-1}$) and the ratio of water storage/surface area (mean depth, 7.5 m). According to OECD criteria and trophic state index based on Chl-a concentration, 34.3 and 72.8% of selected reservoirs appeared to be eutrophic, respectively. Characteristics of TYPE ll reservoirs generally showed high Chl-a concentration, relatively old age, small DA/LA ratio, short Hydraulic retention time, large paddy field and field to watershed ratio, and high pollutant loading compared to other types of reservoirs. The difference of TP concentration was greater than that of TN concentration in reservoir water among classified four types. Based on TN/TP ratio (by weight), phosphorus was limiting nutrient in all types and more closely related with Chl- a concentration than nitrogen. Significant decrease of Chl- a concentration with increase of TN/TP ratio observed only in reservoirs with Chl-a concentration > 25${\mu}g\;L^{-1}$. Although drainage area is believed to be a factor that is related to the generation load of pollutants in the watershed, it did not show any significant relationship with water quality parameters. Morphometric characteristics such as depth and age of reservoir as well as type of land use patterns in the watershed was among important parameters for the assessment of water quality characteristics in Korean reservoirs.

• Journal of Plant Biology
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• v.5 no.4
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• pp.1-5
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• 1962

CHA, Jong Whan (Dept. of Biology, College of Education, Seoul National University). Effect of gibberallin on the growth and internal componsents of Astragalus sinicus L. Kor. Jour. Bot. V(4) : 1-5, 1962. The effect of GA on the growth as well as on the internal components of the leaves of Astragalus sinicus L. under the soil culture was investigated. The result has indicated that small variation in the relative concentration of GA treated on the leaves shows a marked influence on the internal components of the plants. The increase of growth was associated with increasing intensity of GA. Chlorophyll and carotene contents in the leaves were depressed with increasing concentration of GA. It was noticed that the growth was pomoted with the decrease of the contents of chlorophyll and carotene. In contrast the aacorbic acid in the leaves treated with GA decreased in proportion to the degree of the concentration of GA. Carotens content varied with chlorophyll, although the ratio of chlorophyll to carotene was not so high as the results obtained by Beck and Redman. Chlorophyll and ascorbic acid values with respect to growth differed greatly during the two experimental periods. The chlorophyll content was found highly significant in this experimental periods. The chlorophyll content was found highly significant in this experiment. As the concentration of GA was increased, it was noticed that there was a reduction of anthocyanin, sucrose, and reducing sugar contents. The anthocyanin content was not so high in this study as in the results obtained from the corn by Jacob Straus.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.273-282
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• 2008

The relationship between water deficit stress and monodehydroascorbate reductase (MDHAR) activity was determined in lettuce (Lactuca sativa L.) leaves under water stress condition imposed by with-holding water for 72 hrs. Relative water content determined in water deficit stressed lettuce leaves gradually reduced from 91.29% to 74.58%, and water content of medium drastically decreased 4.73% after quitting of irrigation. Hydrogen peroxide content in leaves subjected to water deficit stress rapidly increased, but soluble protein content rapidly decreased when those were compared to control plant. The relationship between relative water content and hydrogen peroxide content in stressed leaves positively correlated with $R^2$=0.8851, but soluble protein content reversely correlated with $R^2$=0.9826. Total chlorophyll content in stressed plant leaves was higher than that of control plant, and increased rapidly in early stage of treatment of both stressed and control plants. Carotenoid content was higher than that of control plant, and the ratio of carotenoid to total chlorophyll in stressed plant was higher as compared to control plant. As water deficit stress continued progressively, total ascorbate content in stressed plant leaves was a little higher than that of control plant. But dehydroascorbate (DHA) content within 6 hr of water deficit stress was higher than that of control plant, and then, content of control plant in 12 hr of stress treatment higher than that of stressed leaves. The activity of monodehydroascorbate reductase of cytosolic and chloroplastic tractions increased dramatically, and mRNA of MDHAR was highly detected by probing $^{32}P$-labeled single stranded MDHAR RNA of lettuce plant leaves subjected to water deficit stress. Relationship between MDHAR activity and relative water content and hydrogen peroxide highly correlated with $R^2$=0.9937 and 0.8645, respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.2
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• pp.97-102
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• 1999

This study was conducted to compare seasonal changes of height, diameter at root collar, biomass and chlorophyll contents of Abies holophylla seedlings grown in Sangju National University Nursery under different light intensities. Four light intensities were adopted using nylon net such as 100% sunlight(1800 $\mu$㏖ m$^{-2}$ s$^{-1}$ ), 75% of sunlight (1350 $\mu$㏖ m$^{-2}$ s$^{-1}$ ), 50% of sunlight (900 $\mu$㏖ m$^{-2}$ s$^{-1}$ ) and 25% of sunlight (450 $\mu$㏖ m$^{-2}$ s$^{-1}$ ). Planting density in four light intensities was 30 cm$\times$30 cm. In each treatment, 100 trees were planted and height, diameter at root collar, biomass and chlorophyll contents were measured. The highest height, diameter at root collar and biomass in Abies holophylla seedlings were observed at 100% full sunlight. Lowest chlorophyll contents (Chlorophyll a, b and total) were shown at 25% of sunlight, lowest light intensity treatment in this study. Growths and chlorophyll contents of Abies holophylla seedlings were strongly associated with light intensity. Photosynthesis has to be investigated in near future because photosynthesis and chlorophyll contents were strongly related to tree growth with long periods.