• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.442-449
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• 2004

Improving the light utilization efficiency of photosynthetic cells in photobioreactors (PBRs) is a major topic in algal biotechnology. Accordingly, in the current study we investigated the effect and suitability of photosynthetic pigment reduction for improving light utilization efficiency. The light-harvesting complex II (LH-II) genes of Rhodobacter sphaeroides were removed to construct a mutant strain with less pigment content. The mutant strain exhibited a slower growth rate than the wild-type under a low light intensity, while the mutant grew faster under a high light intensity. In addition, the specific absorption coefficient was lower in the mutant due to its reduced pigment content, thus it seemed that light penetrated deeper into its culture broth. However, the distance (light penetration depth) from the surface of the PBR to the compensation point did not increase, due to an increase in the compensation irradiance of the mutant strain. Experimental data showed that a reduced photosynthetic pigment content, which lessened the photoinhibition under high-intensity light, helped the volumetric productivity of photosynthetic microorganisms.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.267-271
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• 2003

To elucidate effects of air pollutants on ecophysiological properties of two Quercus mongolica stands at different levels of air pollution, photosynthetic capacity and chloroplast pigment were measured in leaves of Q. mongolica. Photosynthetic capacity, photosynthetic pigment content and SLA (specific leaf area) of Q. mongolica leaves in polluted area were lower than those in nonpolluted area. Also, the chlorosis and mottling in some of leaves were observed in polluted area after August. Except for total carotenoid (P<0.05) the correlations between photosynthetic capacity and pigment content were not significant. Photosynthetic capacity of Q. mongolica leaves in polluted area was decreased after July.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.189-192
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• 2000

The objective of this study was to investigate the effect of high content of light-absorbing pigments on overall photosynthetic efficiency in high density microalgal cultures. The light harvesting complex II (LHC II) regulating gene of Rhodobacter sphaeroides, photosynthetic purple bacterium, was removed to construct a mutant strain that had less pigment content. The mutant and wild type strains were cultured under various light intensity by adjusting the distance from the light source. The productivity of the mutant strain was higher at high light intensity (over 118 ${\mu}E/m^2/s$) compared with one of the wild type , and was lower at low light intensity (34 ${\mu}E/m^2/s$). Especially, the concentration of LHC II mutant strain was 56% higher at 118 ${\mu}E/m^2/s$. The reduction of per cell pigment contents in the mutant strain lessened the degree of the mutual shading and thus enhanced the overall photosynthetic efficiency.

• ALGAE
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• v.18 no.1
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• pp.83-88
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• 2003

• ALGAE
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• v.20 no.4
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• pp.369-377
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• 2005

Seashore joining with land and sea, which is typical habitat for marine macroalgae, is classified two types of shore as soft- and hard-bottom shore according to topographical (geological) and ecological features. We compared two of Ulva pertusa Kjellman from two contrasting habitats, sandy (soft-bottom, Haenam) and rocky shore (hard-bottom, Hadong) in terms of chlorophyll-a fluorescence and its parameters, and various photosynthetic pigment and nutrient content in the tissue of those. Both of habitats were different in the light environment such as light attenuation coefficient and even in nutrient concentration of ambient seawater. Electron transport rate (ETR) of Ulva from sandy shore was higher than from rocky shore. The range of photosynthetic pigment content in the tissue of U. pertusa was significantly much more in from sandy shore, and also nitrogen and phosphorus content were significantly higher except for carbon content. However, there were no significant differences in the ratio of among photosynthetic pigments, and N:P ratio was similar between each other, even though significantly different. Our result implied on the reason of why most of green tides in the worldwide concentrated and frequently occurred at sites with sandy, muddy and silty bottoms, being classified as soft-bottom shore.

• ALGAE
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• v.18 no.1
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• pp.95-100
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• 2003

• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.878-884
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• 2010

Ozone sensitivity of physiological indicators and the difference of ozone tolerance on 4 families of Quercus aliena seedlings were investigated on the basis of the standardized physiological indicators. Photosynthetic parameters, photosynthetic pigment and malondialdehyde (MDA) content, and antioxidative enzyme activities were measured or analyzed from the leaves of Q. aliena seedlings at the end of ozone fumigation, and ozone tolerance indices among 4 families were calculated with the standardized physiological parameters. After ozone treatment, the reduction of carboxylation efficiency was observed in the leaves of four families, and their reduction were ranged from -24.1% to -56.9% of control seedlings. Photosynthetic pigment content differed significantly among 4 families and treatments. The reduction of total chlorophyll content showed the highest in family SU4 (-40.6%) and the lowest family US2 (-18.8%). Ascorbate-peroxidase (APX) activity showed significant difference among families and treatments, and increased as compared with control in three families, except for family US2. On the basis of the physiological indices, ozone tolerance of four families was ranked in the order of US1 > SU4 > US2 > SU1. In conclusion, photosynthetic parameters, pigment content and APX activity were recommended as appropriate indicators to assess the tolerance against ozone stress of Q. aliena.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.1
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• pp.18-23
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• 2003

This study was conducted to compare physiological responses of Pinus densiflora, Populus ${\times}$ tomentiglandulosa, Quercus acutissima and Eleutherococcus sessiliflorus exposed to SO$_2$, by measuring photosynthetic pigment contents and SOD activity. Four woody plants were exposed to relatively high SO$_2$ concentration (500 ppb, 800 ppb) for 8h day$^{-1}$ for 7 days in a chamber. Photosynthetic pigment contents in the leaves of four species decreased with increase of SO$_2$ concentration; also chlorophyll a, chlorophyll b and total carotenoid content were significantly different among tree species and treatments. The ratio of chlorophyll b to chlorophyll a of E. sessiliflorus and Q. acutissima increased for 500 ppb treatment but decreased at 800 ppb. This result showed that chlorophyll a was destroyed by 500 ppb SO$_2$ and chlorophyll b by 800 ppb SO$_2$. Therefore, the sensitivity of chlorophyll a to SO$_2$ may be higher than that of chlorophyll b. SOD activity differed significantly between species and treatments. SOD activity of E. sessiliflorus and Q. acutissima increased at 500 ppb but decreased at 800 ppb, but P. densiflora and P ${\times}$tomentiglandulosa maintained high SOD activity at both 500 ppb and 800 ppb. Based on the photosynthetic pigment contents and SOD activity in the leaves of four tree species, the tolerance of P. ${\times}$ tomentiglandulosa to SO$_2$ was the highest of four tree species.

• Korean Journal of Environmental Biology
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• v.26 no.1
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• pp.15-21
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• 2008

Ionizing radiation causes many alterations in photosynthetic machineries. However, there is no information about effects of ionizing radiation on the development of photosynthetic machineries in plants. We investigated the greening of etiolated mung bean seedlings after gamma-irradiation of 50 to 300 Gy. The irradiation inhibited seedling growth with great dependence on the radiation dose. In particular, growth of stems was more affected than that of hypocotyls. Irradiated leaves showed inhibition in growth, aberration in morphology, and yellowing in color depending on the radiation dose. Contents of photosynthetic pigments such as chlorophylls and carotenoids were significantly decreased in the irradiated leaves. The apparent electron transport rate for photosynthesis, ETR, was similarly changed depending on the radiation dose. However, the maximal photochemical efficiency of Photosystem II (PSII), Fv/Fm, was little affected by the irradiation. Moreover, the 50-Gy seedlings maintained the control level of light saturating for photosynthesis and showed slightly higher Fv/Fm values in spite of significant decreases in the photosynthetic pigment content and ETR. These results suggest that the inhibition of the overall photosynthetic capacity couldn’t be causally relatqaed with the repression in the initial development of irradiated seedlings and that the overall photosynthetic machineries can develop and work to some extent as a concerted system for photosynthesis even after exposure to acute doses of ionizing radiation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.3
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• pp.173-182
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• 2010

This study was conducted to investigate ozone sensitivity of physiological indicators and the difference in ozone tolerance of 8 families of Sophora japonica seedlings on the basis of the standardized physiological indicators. After ozone treatment, photosynthetic parameters, photosynthetic pigments and malondialdehyde (MDA) content, and antioxidative enzyme activities were analyzed from the leaves of S. japonica seedlings. Ozone tolerance indices among 8 families were calculated with the standardized physiological parameters. In addition, the reduction of carboxylation efficiency and apparent quantum yield were observed in the leaves of seven families, except for family No. 6 and 7, respectively. The apparent quantum yield varied from -27% to -61% of the control seedlings. Photosynthetic pigment content differed significantly among 8 families, but was not affected significantly by ozone treatment. Superoxide dismutase (SOD) activity increased from 7% to 64% after ozone exposure, and significant difference existed among 8 families. Ascorbate-peroxidase (APX) activity of 8 families increased by ozone treatment, and the activity of family No. 7 showed the highest increase (218%) in comparison to their respective control plants. On the basis of the standardized indices, family No. 6 showed the lowest tolerance by indicating higher reduction of both photosynthetic parameters and pigment content and lower increase of antioxidative enzyme activities. On the contrary, family No. 7 showed the highest tolerance as indicated by lower reduction of photosynthetic parameters, higher amounts of photosynthetic pigments, and higher enzyme activity.