• Korean Journal of Environmental Agriculture
• /
• v.20 no.2
• /
• pp.93-98
• /
• 2001

A chilling-tolerant japonica-type and a chilling-susceptible indica-type of rice (Oryza sativa L.) plants were compared with respect to various physiological parameters during chilling and subsequent recovery. The japonica-type and the indica-type of rice cultivars used were Ilpumbyeo and Taebaekbyeo, respectively. The two rice cultivars exhibited little or no differences in the changes of leaf fresh weight and chlorophyll content during chilling at $5^{\circ}C$ for 3 days. During subsequent recovery at $25^{\circ}C$, however, Ilpumbyeo restored its growth more rapidly than Taebaekbyeo. Since the changes of relative water content, malondialdehyde production, an estimate of lipid peroxidation, and chlorophyll fluorescence were significantly different in the two rice cultivars during the chilling and subsequent recovery, they were found to be more sensitive physiological parameters than fresh weight and chlorophyll content. However, the differences in relation to water content, malondialdehyde production, and chlorophyll fluorescence between the two rice cultivars were smaller during chilling than those during subsequent recovery. These results suggest that relative water content, malondialdehyde production, and chlorophyll fluorescence could widely be used as important physiological parameters for screening chilling-tolerant plants.

• Journal of Aquaculture
• /
• v.9 no.1
• /
• pp.65-71
• /
• 1996

To estimate the variation of food organisms on the corrugated PVC sheets, we analysed the chlorophyll a and. pheopigments of the benthic microalgae on the sheets from the oyster culture ponds. We estimated the standing crops as the amounts of chlorophyll a, and the physiological state of cells as the pheopigments level in the benthic microalgae. The amount of chlorophyll a was increased by immersion time in winter but the peak was observed every two weeks in summer, while the ratio of pheopigments was highest in summer but the low level was observed in spring and autumn. These seasonal variation were well coincided with the natural spawning season and the good microalgae nutritional valance.

• Journal of Korean Society of Forest Science
• /
• v.76 no.1
• /
• pp.11-16
• /
• 1987

With the purpose of pursuing the increase and decrease of chlorophyll a and chlorophyll b caused by application of the simulated acid rain treatment on Pinus koraiensis seedlings and Ligustrum obtusifolium cuttings, the experimental design of randomized block arrangement with three replications was implemented in the experimental field of Yesan National Agricultural Junior College, during the growing season of 1985. Pinus koraiensis seeds stratified in cool and moist condition were sown on pots, and in case of Ligustrum obtusifolium, C1/1 cuttings were potted for experimental use in the early spring. The regime of artificial acid rain, based upon precipitation frequency and density, was simulated from the learning of climatological data averaged from 30 years records. The spray of acid water containing pH values of 4.0 and 2.0 was initiated from the 1st of May and ended on the 31st of August. As control, ground water was also treated at the same time. To analyse the chlorophyll content, those leaves looking representative and unaffected by other harmful agents were sampled on the 18th of September, and UV-visible spectrophotometer was used. With decrease in pH values of acid rain, the content of chlorophyll a and chlorophyll b decreased in both species. The decrease in chlorophyll a could be confirmed through statistical significance, but not in chlorophyll b. And when we discussed the chlorophyll decrease index which was explained in detail in the paper, an attention might be given to similarly decreasing values in both chlorophyll a and chlorophyll b, according as pH levels of acid rain decreased. The ratios of chlorophyll a to chlorophyll b in both species were not affected by different pH leaves of acid rain.

• Korean Journal of Environment and Ecology
• /
• v.28 no.5
• /
• pp.500-509
• /
• 2014

To prevent freezing of the road by fallen snow, Calcium chloride($CaCl_2$) as a deicer is used to very often and it can be harmful to roadside trees. This study was conducted to investigate the effects of Calcium chloride($CaCl_2$) as a deicer on growth and physiological traits of Acer triflorum according to different concentration of $CaCl_2$. We measured growth, chlorophyll contents, gas exchangement characteristics, chlorophyll fluorescence and mineral nutrition concentration in plant and soil. The experimental group was composed of four treatments including 0mM(control), 9mM(0.5 %), 18mM(1.0 %), 54mM(3.0 %). Before germinating new shoot, the dissolution of $CaCl_2$ was irrigated twice interval of a week. At 30 days after treatment, all treatments decreased total cholorophyll content, photosynthetic rate, transpiration rate, stomatal conductance and photochemical efficiency($F_v/F_m$) with increasing concentration of $CaCl_2$ and especially, they significantly reduced in 3.0 % treatment. In contrast, chlorophyll a/b ratio increased with an increase of $CaCl_2$ concentration and water use efficiency increased in 1.0 % and 3.0 % treatments. At 50 days after treatment, all treatments were decreased in chl a, chl b, total chlorophyll content, carotenoid content, photosynthetic capacity, photochemical efficiency($F_v/F_m$) and quantum yield of photosystem II(${\Phi}_{PSII}$) compared with control and 3.0 % treatments were withered. $Ca^{2+}$ and $Cl^-$ were accumulated in leaves and soil, which inhibited water absorption and electron transport and it caused the reduction of height growth rate more than 50 %. Although there was a little difference according to time and $CaCl_2$ concentration, all treatments decreased in growth rate and physiological activity slowed down. As time passed, these results got worse. Therefore we need to take a measure earlier in order to minimize damage of trees.

• Korean Journal of Ecology and Environment
• /
• v.35 no.1 s.97
• /
• pp.36-44
• /
• 2002

The spatial and temporal trends of water qualities in Lake Soyang was statistically analyzed in this study. The water qualities include nutrients, ionic contents and chlorophyll-a (Chl-a) measured during 1993${\sim}$2000. The rainfall intensity and runoff from the catchment appeared to play an important role in water quality trends in the lake. According to seasonal Mann-Kendall test, conductivity, TP, and Ctl-a did not show any trends of increase or decrease over the 8 year period, while TN declined slightly. It was found that the variation of TP was a function of interannual inflow and rainfall. In the analyses of spatial trend, conductivity, based on the mean by site, showed a downlake decline over the eight year period. Minimum conductivity was found in the headwaters during summer monsoon of July to August and near the dam during October. This result indicates a time-lag phenomenon that the headwater is diluted by rainwater immediately after summer monsoon rain and then the lake water near the dam is completely diluted in October. During summer period, TP and TN had an inverse relation with conductivity values. Concentrations of TP peaked during July to September in the headwaters and during September in the downlake. Also, TN increase during the summer and was more than 1.5 mg/L regardless of season and location, indicating a consistent eutrophic state. Values of Chl-a varied depending on location and season, but peaked in the midlake rather than in the headwaters during the monsoon. Regression analyses of log-transformed seasonal Chl-a against TP showed that value of $R^2$ was below 0.003 in the premonsoon and monsoon seasons but was 0.82 during the postmonsoon, indicating a greater algal response to the phosphorus during the postmonsoon. In contrast, TN had no any relations with Chl-a during all seasons.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.4 no.2
• /
• pp.101-106
• /
• 1999

The down-core distribution of chlorophyll a, organic carbon contents and ${\delta}^{13}C$ in the bottom sediments were measured to understand the evolution of eutrophication in Masan Bay. Bottom sediment were collected in January 1994. The chlorophyll a and organic carbon contents in the sediment core decreased with increasing sediment depth, respectively. Bottom sediments (0~20 cm) in Masan Bay was rich in chlorophyll a (avg. 9.6 ${\mu}g\;g^{-1}$ dryweight) and organic C (avg. 2.5%). The down-core distribution of chlorophyll a suggests that the inner part of Masan Bay has experienced the acceleration of chlorophyll a supply since 1960s. Flux of organic carbon to the sea floor is in the range of 10 $gCm^{-2}\;yr^{-1}$ assuming the C:Chl a ratio of 25. It suggests tht approximately 1.3% of the fixed carbon by phytoplankton appears to be deposited in the bottom sediments.

• Korean Journal of Remote Sensing
• /
• v.37 no.5_1
• /
• pp.1111-1124
• /
• 2021

Mudflats are crucial for understanding the ecological structure and biological function of coastal ecosystem because of its high primary production by microalgae. There have been many studies on measuring primary productivity of tidal flats for the estimation of organic carbon abundance, but it is relatively recent that optical remote sensing technique, particularly hyperspectral sensing, was used for it. This study investigates hyperspectral sensing of chlorophyll concentration on a tidal flat surface, which is a key variable in deriving primary productivity. The study site is a mudflat in Geunso bay, South Korea and field campaigns were conducted at ebb tide in April and June 2021. Hyperspectral reflectance of the mudflat surfaces was measured with two types of hyperspectral sensors; TriOS RAMSES (directionalsensor) and the Specim-IQ (camera sensor), and Normal Differenced Vegetation Index (NDVI) and Contiuum Removal Depth (CRD) were used to estimate Chl-a from the optical measurements. The validation performed against independent field measurements of Chl-a showed that both CRD and NDVI can retrieve surface Chl-a with R² around 0.7 for the Chl-a range of 0~150 mg/m² tested in this study.

• Journal of Korean Society of Forest Science
• /
• v.100 no.4
• /
• pp.733-737
• /
• 2011

We investigated the effect of artificial warming on chlorophyll contents and net photosynthetic rates of 2-year-old Quercus variabilis seedlings in a nursery open-field experiment site. 64 seedlings were each planted in $1m{\times}1m$ plots (n = 4) and warmed with infrared lamps. The air temperature in warmed plots was $3^{\circ}C$ higher than that of control plots. Chlorophyll contents and net photosynthetic rates were measured in May, July, August, September and October, 2011. In May, September and October chlorophyll contents and net photosynthetic rates were significantly higher in warmed plots than in control plots. However, there were no significant differences in chlorophyll contents and net photosynthetic rates between warmed plots and control plots in July and August. It seemed that early developed leaves of warmed plots in May with higher chlorophyll contents could lead to higher net photosynthetic rates whereas there was no difference in net photosynthetic rates due to saturation of chlorophyll contents in July and August. Increased biosynthesis of chlorophyll due to warming might increase net photosynthetic rates in September and October.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.16 no.1
• /
• pp.59-66
• /
• 2013

When the typhoons are passing over the ocean, the ocean environment has both physical and biological impacts on the East, South sea and Yellow sea of Korea. As a result of typhoon path, vertical mixing and upwelling injured colder subsurface water, and leaded to phytoplankton blooming along the typhoons. The ocean environment before and after a typhoon played an important role in the biological effect of sea surface. Although the magnitude of sea surface temperature (SST) gets cooler because of typhoon path, other physical and biophysical responses are quite different such as chlorophyll, K490 and SST. The purpose of this study is to compare with the typhoon path that influenced the Korean Peninsula and ocean environment parameters which were observed by ocean color remotely-sensed data. The MODIS data were used to assess the parameters of ocean environments such as K490 and chlorophyll data from 2002 to 2005. Mean chlorophyll from MODIS data increased by about 1-4% in the East sea after the typhoon. Mean concentration of MODIS chlorophyll in the post-typhoon period increased along the typhoon passage. However, Jeju coastal area has different patterns from those of the East sea.

• Journal of Environmental Science International
• /
• v.4 no.4
• /
• pp.335-344
• /
• 1995

Developmental changes of chlorophyll-protein complexes (CPs) and plastid membrane proteins in greening mung bean cotyledons and the effect of spermine therein were examined by SDS-polyacrylamide gel electrophoresis. The changes in the amounts of CPs became larger with the progress of greening and light-harvesting chlorophyll a/b protein (LHCP) was the main CP in the early greening stage up to f h. As the greening proceeded, chlorophyll-protein of the photosystem I (CPI) accumulated. Application of spermine were effective in accumulating CPs of the thylakoid membrane in the early phase of greening. In the profiles of the plastid membrane proteins, quantitative and qualitative changes were observed with the onset of greening up to 72 h. 56 kD protein of major intensity was observed in all greened chloroplasts and 24 kD protein increased remarkablly in both control and spermine-treated cotyledons. The thylakoids from spermine-treated cotyledons showed hither amounts of thylakoid proteins as compared to the controls. The results suggest that spermine may play a role in the regulation of plastid development and stabilizes the membrane function during greening.