• Journal of Environmental Science International
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• v.23 no.12
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• pp.2015-2028
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• 2014

We analyzed with HPLC (High Performance Liquid Chromatography) analysis photosynthetic pigments and environmental factors, microscopic observations of the phytoplankton and zooplankton in the seawater every month from February 2009 to November 2010 in Haengam Bay. The level of dissolved inorganic nutrients was the highest between July and September, when freshwater influx was at its peak, whereas chlorophyll a levels were the highest in April and August. Also, phytoplankton pigment concentration increased when dissolved inorganic nutrients are carried into nearshore waters by rainfall runoff. Based on identification of phytoplankton and photosynthetic pigments results, diatoms were mainly dominant while dinoflagellate populations increased at July and August 2009, May 2010. The zooplankton communities are dominated in terms of Noctiluca scintillans. The contribution of Noctiluca scintillans in 2010 accounts for approximately 77.3% of the total zooplankton. Distribution patterns over time of zooplankton in the seasonal distribution of phytoplankton showed a different pattern.

• Ocean and Polar Research
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• v.34 no.2
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• pp.111-123
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• 2012

To understand the phytoplankton community in the eastern part of the Yellow Sea (EYS), in the summer, field survey was conducted at 25 stations in June 2009, and water samples were analyzed using a epifluorescence microscopy, flow cytometry and HPLC method. The EYS could be divided into four areas by a cluster analysis, using phytoplankton group abundances: coastal mixing area, Anma-do area, transition water, and the central Yellow Sea. In the coastal mixing area, water column was well mixed vertically, and phytoplankton was dominated by diatoms, chrysophytes, dinoflagellates and nanoflagellates, showing high abundance ($>10^5\;cells\;l^{-1}$). In Anma-do coastal waters characterized by high dominance of dinoflagellates, high phytoplankton abundance and biomass separated from other coastal mixing area. The southeastern upwelling area was expanded from Jin-do to Heuksan-do, by a tidal mixing and coastal upwelling in the southern area of Manjae-do, and phytoplankton was dominated by benthic diatoms, nanoflagellates and Synechococcus group in this area. Phytoplankton abundance and biomass dominated by pico- and nanophytoplankton were low values in the transition waters and the central Yellow Sea. In the surface of the central Yellow Sea, high dominance of photosynthetic pigments, 19'-hexanoyloxyfucoxanthin and zeaxanthin implies that haptophytes and cyanobacteria could be the dominant group during the summer. These results indicate that the phytoplankton communities in the EYS were significantly affected by the formation of tidal front, thermal stratification, and coastal upwelling showing the differences of physical and chemical characteristics during the summer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.403-407
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• 1986

The rice leaf color, which was one of main factors to determine application time of fertilizers, was analyzed in visible region, while the distinction of photosynthetic pigments controlling the rice leaf color was separated by T.L.C. The light absorption peaks of ethyl ether extracts of rice leaf blades were occurred in 413, 432, 453 and 662nm. Especially, the maximal light absorption was 432nm in blue and 662nm in red region. The both light absorption ratios (blue to red region) was not greatly different among rice ecotypes, whereas decreasing tendency in increased fertilization was observed. There was a significant negative correlation between the both light absorption ratios and the values of color chart, and the content of chlorophyll in rice leaf blades. The composition ratio of chorophyll was larger than that of carotenoid at heading stage, and the carotenoid was larger than the chlorophyll at 30 days after heading. The composition ratio of chlorophyll among photosynthetic pigments according to rice ecotypes, Japonica x Indica cultivars were larger than Japonica cultivars at heading stage, and Japonica cultivars were larger than Japonica x Indica cultivars at 30 days after heading, while carotene was vice versa.

• Journal of Environmental Science International
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• v.5 no.2
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• pp.153-170
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• 1996

Photosynthetic pigments and their degradation products in suspended and sinking particles collected from the Gulf of Mexico waters 1987~88, were measured using High Performance liquid Chromatography (HPIC). The short term variations in flux rates of chlorophylls and carotenoids as well as-their degradation products were compared at the mesoscale cyclonic and anticyclonic circulation features (cold joie rink and warm core ring). Chlorophyll a was the predominant porphyrin of suspended particulate matter at both CCR -and WCR. Among carotenoid pigments, 19'-hexanoyloxyfucoxanthin, which is a biomarker of prymnesiophytes, was dominant pigment at both rinds. Phaeophorbide a, which is produced through the Brazing processes of grazers, was the predominant degraded pigment in sinking particles ai the study aiea. Total pigment flux in CCR was an order of magnitude higher than that in WCR. Less than l% of the standing stock of the pigments measured sank out of the upper 200m of the WCR on any given day. Thus, suspended particulate matter in Gulf of Medico was not recycled rapidly.

• ALGAE
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• v.36 no.3
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• pp.195-206
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• 2021

Increasing inputs of dissolved organic matter (DOM) to northern lakes is resulting in 'lake browning.' Lake browning profoundly affects phytoplankton community composition by modifying two important environmental drivers-light and nutrients. The impact of increased DOM on native isolates of red and green-pigmented cyanobacteria identified as Pseudanabaena, which emerged from a Dolichospermum bloom (Dickson Lake, Algonquin Provincial Park, Ontario, Canada) in 2015, were examined under controlled laboratory conditions. The genomes were sequenced to identify phylogenetic relatedness and physiological similarities, and the physical and chemical effects of increased DOM on cellular performance and competitiveness were assessed. Our study findings were that the isolated red and green phenotypes are two distinct species belonging to the genus Pseudanabaena; that both isolates remained physiologically unaffected when grown independently under defined DOM regimes; and that neither red nor green phenotype achieved a competitive advantage when grown together under defined DOM regimes. While photosynthetic pigment diversity among phytoplankton offers niche-differentiation opportunities, the results of this study illustrate the coexistence of two distinct photosynthetic pigment phenotypes under increasing DOM conditions.

• FLOWER RESEARCH JOURNAL
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• v.16 no.3
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• pp.153-160
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• 2008

This experiment was conducted to find out an adequate shading level (0, 55, 74, and 95%) on the shoot growth of rooted cuttings of native Hydrangea serrata for. acuminata. New shoot height (NSH), length and width of leaf, and stem diameter under 55% shading were the greatest. Net photosynthetic rate under 55% shading was the greatest, while intercellular $CO_2$ concentration was the least in this treatment. The greatest content of photosynthetic pigments (total chlorophyll, carotenoid) was observed in leaves grown under a 74%, followed by a 55% shading level. Leaf stomata were observed on the abaxial surface, but those on adaxial surface in all shading treatments were not observed. In 95% shading, decreased stomatal density and development were observed. Higher stomatal density and development, however, were observed in 55% shading. Therefore, it is concluded that a 55% shading level was the optimum for growth of new shoots of rooted cuttings of native H. serrata for. acuminata.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.368-376
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• 2003

The UV-B sensitivity was tested for the intertidal species Chondrus ocellatus from Korea, by measuring photosynthesis estimated as effective quantum yield ($\Phi_{PSII}$) of photosystem II (PS II), growth and content and composition of photosynthetic pigments and UV-absorbing pigments (UVAPs). The $$\Phi_{PSII}$ of the alga decreased with increasing time of exposure to UV-B radiation, followed by fast and nearly full recovery indicating dynamic photoinhibiton. Fresh weight-based growth and pigment contents of C. ocellatus were not seriously affected by UV-B radiation. A single broad peak at 327 nm was obtained from methanol extracts of C. ocellatus, and the absorbance peak increased with increasing UV. The single peak was resolved into three peaks (311, 330 and 336 nm) by the fourth -derivative, and quantitative change in response to UV-B radiation occurred only at 330 nm. High performance liquid chromatography (HPLC) analysis of purified extracts indicated that three MAAs (mycosporine-like amino acids) are present, asterina 330, palythine and shinorine. Field observations during three growing months showed that C. ocellatus exhibit the highest amount of UVAPs in May followed by July and little trace in September, coinciding with the species' phenology. In an ecological context, dynamic photoinhibition as well as accumulation of UVAPs may enable the shallow water red alga C. ocellatus to be well adapted to high UV-B environments.

• Journal of Photoscience
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• v.8 no.1
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• pp.1-7
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• 2001

The deteriorative effect of ultraviolet-B(UV-B) radiation on photosynthesis was assessed by the simultaneous measurement of O$_2$ evolution and chlorophyll(Chl) fluorescence in green pepper. UV-B was given at the intensity of 1 W$.$m$\^$-2/, a dosage often encountered in urban area of Seoul in Korea, to detached leaves. Both Pmax and quantum yield of O$_2$ evolution was rapidly decreased, in a parallel phase, with increasing time of UV-B treatment. Chl fluorescence parameters were also significantly affected. Fo was increased while both Fm and Fv were decreased. Photochemical efficiency of PSII(Fv/Fm) was also declined, although to a lesser extent than Pmax. Both qP and NPQ were decreased similarly with increasing time of UV-B treatment. However, PS I remained stable. The addition of lincomycin prior to UV-B treatment accelerated the decline in Fv/Fm to some extent, suggesting that D1 protein turnover may play a role in overcoming the harmful effect of UV-B. The amount of photosynthetic pigments was less affected than photosynthetic response in showing decline in Chl a and carotenoids after 24 h-treatment. Presumptive flavonoid contents, measured by changes in absorbance at 270 nm , 300 nm and 330nm, were all increased by roughly 50% after 8 h-treatment. Among antioxidant enzymes, activities of catalase and peroxidase were steadily increased until 12h of UV-B treatment whereas ascorbate perxidase, dehydroascorvate reductase and glutathione reductase did not show any significant change. The results indicate that deteriorative effect of UV-B on photosynthesis precedes the protection exerted by pigment synthesis and antioxidant enzymes.

• Journal of Ginseng Research
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• v.14 no.1
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• pp.57-62
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• 1990

In order to Investigate the mechanism of the leaf-burning disease of ginseng (Panax ginseng C.A. Meyer), studies on the generation of singlet oxygen (1O2) and the photooxidation of the pigments were carried out in comparison with the ones of soybean (G1ycine max L). The studies were mainly focalized on the effects of light intensity, light intensity, inhibitor and electron donor/acceptor of the Photosynthetic electron transport system. When we measured the amounts of 1O2 generated in the thylakoids of ginseng and soybean by the irradiation of light (300 w/m2) as a function its time. It was identified that a higher amount of 1O2 was formed in the ginseng thylakoid than the case of soybean. A generation ratio of lO2 between ginseng and soybean sltbstantially identical in the range of light intensities 50∼150w/m2 However much higher amount of 1O2 was generated in ginseng by irradiation of strong intensity of light (200 500w/m2). Wave length dependency on the generation of 1O2 and the pigment photooxidation was observed on ginseng thylakoids; red light (600-700 nm) gave a maximum effect in the contrast with blur green light (400-60 nm). When the ginseng thylalioid was treated with the electron donor (Mn2+) and acceptors (DCPIP, FeCy) of the photosynthetic electron transport system. a drastic inhibition of 1O2 generation was observed. However, treatment with its inhibitors (DCMU, KCW) activated 1O2 generation. An interesting fact that an electron donor or acceptor of the photosystem II(P680) Inhibited 1O2 generation, suggests an intimate relationship between 1O2 generation and photosystem II.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.1-14
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• 2024

High soil salinity is the most severe threat to global rice production as it causes a significant decline in rice yield. Here, we investigated the effects of various plant extracts on rice plant stress associated with high salinity. Additionally, we examined various physiological and biochemical parameters such as growth, photosynthetic activity, chlorophyll content, and lipid peroxidation - in rice plants after treatment with selected plant extracts under salt stress conditions. Of the 11 extracts tested, four - soybean leaf, soybean stem, moringa (Moringa oleifera), and Undaria pinnatifida extracts - were found to effectively reduce salt stress. A reduction of only 3-23% in shoot fresh weight was observed in rice plants under salt stress that were treated with these extracts, compared to the 43% reduction observed in plants that were exposed to stress but not given plant extract treatments (control plants). The effectiveness varied with the concentration of the plant extracts. Water content was higher in rice plants treated with the extracts than in the control plants after 6 d of salt stress, but not after 4 d of salt stress. Although photosynthetic efficiency (Fv/Fm), electron transport rate (ETR), and the content of pigments (chlorophyll and carotenoid) varied based on the types and levels of stress and the extracts that the rice plants were treated with, generally, photosynthetic efficiency and pigment content were higher in the treated rice compared to control plants. Reactive oxygen species (ROS), such as superoxide radicals, hydrogen peroxide (H₂O₂), and malondialdehyde (MDA), increased as the duration of stress increased. ROS and MDA levels were lower in the treated rice than in the control plants. Proline and soluble sugar accumulation also increased with the duration of the stress period. However, proline and soluble sugar accumulation were lower in the treated rice than in the control plants. Generally, the values of all the parameters investigated in this study were similar, regardless of the plant extract used to treat the rice plants. Thus, the extracts found to be effective can be used to alleviate the adverse effects of stress on rice crops associated with high-salinity soils.