• Rapid Communication in Photoscience
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• v.1 no.1
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• pp.21-24
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• 2012

Influence of gamma rays on the cyanobacterium Synechocystis sp. PCC 6803 cells was investigated in terms of a bidirectional hydrogenase, which is encoded by hoxEFUYH genes and responsible for biohydrogen production. Irradiated cells revealed a substantial change in stoichiometry of photosystems at one day after gamma irradiation at different doses. However, as evaluated by the maximal rate of photosynthetic oxygen evolution, maximal photochemical efficiency of photosystem II, and chlorophyll content, net photosynthesis or photosynthetic capacity was not significantly different between the control and irradiated cells. Instead, transcription of hoxE, hoxH, or lexA, which encodes a subunit of bidirectional hydrogenase or the only transcriptional activator, LexA, for hox genes, was commonly enhanced in the irradiated cells. This transcriptional enhancement was more conspicuously observed immediately after gamma irradiation. In contrast, hydrogenase activities were found to somewhat lower in the irradiated cells. Therefore, we propose that transcription of hox genes should be enhanced by gamma irradiation in a LexA-mediated and possibly photosynthesis-independent manner and that this enhancement might not induce a subsequent increase in hydrogenase activities, probably due to the presence of post-transcriptional and/or post-translational regulatory mechanisms.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.2
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• pp.169-174
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• 1982

Light intensities under and above shading material were measured at different layers (upper, middle and lower layers) and lines (lst, 3rd and 5th lines) on clear and cloudy days in S-year-old ginseng plant populations. Rates of photosynthesis and respiration were also measured in field. Light intensities of the 1st lines at upper and lower layers were relatively high as compared with the 3rd and the 5th lines, and there were no remarkable difference between the 3rd and the 5th line. But in middle layer, the light intensity of each line differed considerably. As compared with fair and clear day, the day of clear but much diffuse light showed high light intensity under shading. Relative light intensity was higher on cloudy day than on clear day. There were notable differences of photosynthetic rates among the lines and the rearest lines exhibited the lowest rates. But it was not considered that even the front plants demonstrated the maximum photosynthetic capacity.

• Korean Journal of Medicinal Crop Science
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• v.23 no.2
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• pp.161-167
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• 2015

This study was carried out to determine the effects of light controls and leaf mold on root growth and physiological responses of Atractylodes japonica growing in forest farming. The experiment was performed by light controls (100%, 62.5%, 40.3% and 19.7% of full sunlight) and application of leaf mold to soil. Height, stem diameter, number of flower buds and root collar diameter were the highest in leaf mold within 62.5% of full sunlight (relative light intensity 62.5%). And these were the higher in leaf mold within each light level. As the shading level increased, light saturation point and maximum photosynthesis rate decreased. As the light level decreased, SPAD value increased in control and leaf mold. As a result of surveying the whole experiment, A. japonica was judged worse root growth under the lower light level. It was concluded that the light level was one of the most important factors to produce A. japonica. Also, producing high-quality of A. japonica with the price competitiveness by using leaf mold like the experiment can be an effective way to increase incomes for farmers.

• Journal of Climate Change Research
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• v.5 no.4
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• pp.339-348
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• 2014

Agro-ecosystem plays an important role in the mitigation of atmospheric $CO_2$ concentration through photosynthesis and soil carbon fixation. The perennial crops have capacity of carbon accumulation because they have lived for years in the same position. Carbon dioxide fixation occurs in the fruit orchard by photosynthesis and soil carbon sequestration. The objectives of this review are to introduce the fruit orchard as a carbon dioxide sink and to summarize the methods that measure $CO_2$ flux in the orchard. There are three difference methods (chamber, biomass, and eddy covariance method) to measure $CO_2$ exchanges on sites. However, there is no standard method suitable for fruit cultivation condition in Korea. Thus the standard method have to be developed in order to exactly estimate the carbon accumulation. In foreign studies, the carbon assessments were conducted in apple, peach, olive, grape orchard and so on. On the other hand the estimation of $CO_2$ exchange was carried out for apple and mandarine orchard in Korea. According to these results, fruit orchard is a $CO_2$ sink even though amount of carbon accumulation is smaller than the forest. To introduce certainly fruit orchard as greenhouse gas sink, long-term monitoring and further study have to be conducted under each planting condition.

• Korean Journal of Microbiology
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• v.14 no.4
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• pp.167-175
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• 1976

Twenty one strains of Rhodopseudomonas palustris from 7 different regions in Korea have been isolated and identified on the basis of Bergey's Manual in order to study their regional variation. They can use fructose as carbon source (or hydrogen donor). Capacity to produce molecular hydrogen during photosynthesis was tested using liquid medium, modified by omission of $NH_4Cl$ and addition of L0glutamic acid. As nitrogen source nitrate can be used, and isopropanol can be used as hydrogen donor. their pH ranges are 5.9 - 9.1. Their growth are inhibited in the medium that contains 100 units of penicillin G/ml. as for the growing test in dark aerobic condition, the period needed for adptation is longer than that of Korea strain of Rhodopseudomonas gelatinosa.

• The Plant Pathology Journal
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• v.27 no.2
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• pp.164-169
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• 2011

Previous studies have addressed the management of phyllosphere pathogens by leaf and root-associated microbes. The present study evaluated the effect of the foliar application of three strains of Bacillus spp. on plant growth and fruit quality. The application of a bacilli spore preparation significantly improved leaf growth parameters such as leaf thickness and photosynthesis capacity, indicating that bacilli treatment directly promoted leaf growth. In addition, foliar treatment resulted in an improvement in the key indicators of fruit quality including water, glucose, and sucrose contents. The present results suggest that foliar spraying of beneficial bacilli is a potential treatment of wide application for the improvement of apple quality. Foliar application of bacilli preparation as effective plant growth-promoting rhizobacteria broadens the spectrum of their availability for orchard application.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.2
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• pp.126-130
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• 1985

Photoinhibition studies were conducted with ginseng (Panax ginseng) grown under shade and tobacco (N. tobaccum cv. Bulgaria) grown under full sunlight. The plants were exposed to light intensity of 580, 1280, 1770, 2580 ${\mu}$E/㎡/sec in normal air for 3.6 9 hours. Light saturation of ginseng was observed at 550 ${\mu}$E/㎡/sec and that of tobacco was at 1600 ${\mu}$E/㎡/sec. Tobacco exposed to high light intensity and long duration of light irradiation didn't show entire reduction in photosynthetic capacity. But in ginseng, 20.3% of photosynthesis was reduced in light intensity of 2,580 ${\mu}$E/㎡/sec during 9 hours. Light response in photosynthesis differed considerably between tobacco and ginseng, and ginseng exposed to high light intensity showed remarkable reduction in photosynthesis. The extent of photoinhibition of ginseng was dependent on the length of exposure to the high light intensity. Stomatal resistance of ginseng seemed not to be changed by photoinhibition but mesophyll resistance was increased.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.414-422
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• 2010

The objective of this study was to find optimal water condition of containerized seedling production of two tropical species for high seedling quality. This study was conducted to investigate photosynthesis, water use efficiency(WUE), Stomatal conductance(gs) and growth performances of containerized seedlings of Eucalyptus pellita and Acacia mangium growing under three different irrigation periods (1 time/1 day, 1 time/2 days and 1 time/3 days). E. pellita showed outstanding photosynthetic capacities at 1time/1day irrigation and A. mangium showed good photosynthetic capacity at all treatments. As irrigation period were shortened, gs of two species increased, while WUE of two species decreased. Root collar diameter and height of two species were the highest at 1 time/1 day irrigation, while the lowest at 1 time/3 days irrigation. As irrigation period were shortened, H/D ratio, biomass and seedling quality index (DQI) of two species increased but T/R ratio of two species showed the opposite tendency. These results showed that 1 time/1 day irrigation is optimal water condition of containerized seedling production of two tropical species and irrigation controlling is very important for growth and seedling quality of containerized seedling.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.28-38
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• 2012

This study was conducted to investigate growth performance, photosynthesis, water use efficiency (WUE), and stomatal conductance ($g_s$) of container seedlings of Liriodendron tulipifera and Zelkova serrata growing under three different irrigation periods (1 time/1 day, 1 time/2 days and 1 time/3 days) for high seedling quality. The root collar diameter and height of L. tulipifera and Z. serrata seedlings were highest with 1 time/1 day irrigation, whereas they were lowest with 1 time/3 days irrigation. The two species showed low drought tolerance. As irrigation period was shortened, biomass and seedling quality index (SQI) of the two species increased. The ratio of height to root collar diameter (H/D) and the ratio of below to aboveground biomass (T/R) of the two species were lower with 1 time/3 days than at other irrigation periods. L. tulipifera and Z. serrata seedlings showed significantly higher photosynthetic capacity with 1 time/1 day irrigation. As irrigation period was shortened, $g_s$ of two species increased, while their WUE decreased significantly (P<0.05) These results show that 1 time/1 day irrigation provides the most optimal water condition for container seedling production of two species and irrigation controlling is very important for growth and quality of container seedlings.

• Journal of Photoscience
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• v.12 no.1
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• pp.33-39
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• 2005

Plants possess the ability to dissipate the excitation energy for the protection of photosynthetic apparatus from absorbed excess light. Heat dissipation is regulated by xanthophyll cycle in thylakoid membranes of chloroplasts. We investigated the mechanistic aspects of xanthophyll cycle-dependent photoprotection against low-temperature photoinhibition in plants. Using barley and rice as chilling-resistant species and sensitive ones, respectively, chilling-induced chlorophyll fluorescence quenching, composition of xanthophyll cycle pigments and mRNA expression of the zeaxanthin epoxidase were examined. Chilled barley plants exhibited little changes in chlorophyll fluorescence quenching either of photochemical or non-photochemical nature and in the photosynthetic electron transport, indicating low reduction state of PS II primary electron acceptor. In contrast to the barley, chilled rice showed a marked decline in those parameters mentioned above, indicating the increased reduction state of PS II primary electron acceptor. In addition, barley plants were shown to have a higher capacity to elevate the pool size of xanthophyll cycle pigments in response to cold stress compared to rice plants. Such species-dependent regulation of xanthophyll cycle activity was correlated with the gene expression level of cold-induced zeaxanthin epoxidase. Chilled rice plants depressed the gene expression of zeaxanthin epoxidase, whereas barley increased its expression in response to cold stress. We suggest that chilling-induced alterations in the pool size of xanthophyll cycle pigments related to its capacity would play an important role in regulating plant's sensitivity to chilling stress.