• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.424-431
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• 1995

This study was conducted to evaluate resistance and physiological responses of Zelkova serrata Makino seedlings to ozone in open-top chamber. One-year-old seedlings of Zelkova serrata were planted in pots in April and grown in greenhouse until August. The plants were transferred into two out-door open-top chambers with a dimension of 2.0 m in diameter and 2.0 m in height. First chamber served as a control and was supplied with ambient air. Ozone was added to the second chamber for 5 hours per day(10.00 AM-15.00 PM) for 23 consecutive days at 0.1 ppm. Each chamber housed 70 pots. Every two, three or five days after initiation of exposure, ten pots were randomly removed from the chamber and determined for the contents of chlorophyll a, b, total chlorophyll and ${\beta}$-carotene in the leaves. Photosynthesis and dark respiration were estimated by measuring $CO_2$ absorption in a gas exchange chamber and oxygen absorption by oxygen monitoring system, respectively. Superoxide dismutase(SOD) activity in the leaves was assayed by a xanthine oxidase method. First visible injury of translucent(water-soaked looking) spots appeared on the leaves 14 days after the initial exposure, and ozone accelerated senescence of old leaves. Contents of chlorophyll a and b decreased by 17%, and 31%, respectively, in ozone treatment two days after exposure. The decrease in chlorophyll b was greater than that of chlorophyll a. Content of ${\beta}$-carotene in ozone treatment decreased by 25% two days after initiation of exposure, but the reduction was recovered with time. Photosynthesis decreased by 45%, and the respiration increased by 28% in the ozone treatment. SOD activity started to increase 4 days after beginning of exposure and increased by 285% 7 days after exposure, and decreased to the level below the control treatment with the advancement of the visible injury.

• Journal of Life Science
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• v.6 no.4
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• pp.299-303
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• 1996

The effects of ozone (O$_{3}$) exposures on chlorophyll content of trembling aspen(Populus tremuliodes) rooted cuttings were studied. Ozone was treated with 100 ppb fumigation for 6 hours per day, for three consecutive days per week in open-top chamber. The ozone exposures caused severe foliage damage expressed in necrotic patches and extensive chlorosis. Degradation of chlorophyll was observed mostly in mature leaves. The chlorophyll response to ozone exposure maintained a similar pattern during all experimental seasons and plant materials, Significant genetic variation in O$_{3}$ responses was revealed by differences in sensitivies among clones.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.720-724
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• 1998

Open-top field chamber study was carried out to investigate effect of ambient ozone level on the yield of rice cultivar 'Dongjin' in Kwangyang area located in the vicinity of the industrial complex of Yechon petrolium refinery and chemical works or Kwangyang Iron and Steel works during the summer of 1997. mean ozone concentration of ambient air during daytime (9:00∼17:00) was revealed to exceed over 40 ppb which is defined to be a critical level causing plant injury and yield reduction in Europe. Yield component analysis showed that there was no significant difference in rice yield between ambient air and charcoal-filtered air. The results suggest that the ambient ozone levels during the exposure period had no effect on yield reduction of rice cultivar 'Dongjin' and it is likely that the cultivar is tolerant to ambient ozone levels.

• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.306-313
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• 2001

The objectives of this study were to understand the physiological responses and resistance of red pine trees to ozone exposure in relation to nitrogen and phosphorus fertilization. Potted one-year-old seedlings of Pinus densiflora S. et Z. were exposed in an open-top chamber(OTC) to ozone at concentration of 0.12ppm for 3 hours daily for eight weeks with or without N and P fertilization alone or in combination. The OTC had dimensions of 2.0m in height and 2.5m in diameter, and the air in a control chamber was filtered with activated charcoal to maintain the ozone concentration below 0.02ppm. After eight weeks of ozone exposure, none of the seedlings showed any symptoms of visible injury on leaves. The seedlings fertilized with N and P in a control chamber showed 22 to 95% increase in total dry weight, and similar fertilizer effect was also noticed in an ozone chamber. Ozone treatment did not decrease the total dry weight, but increased shoot/root ratio by 14.5%. Ozone treatment increased sucrose content in the leaves by 23%, but decreased sucrose content in roots by 20% regardless of N or P application. Starch content in the leaves was not affected by either ozone or fertilizer. However, starch content in the roots was decreased by 41% by ozone treatment. Chlorophyll content in the leaves was increased by 70% by N application, but was not affected by ozone treatment. Nitrogen and P fertilization stimulated net photosynthesis by 80% in a control chamber, but stimulatory effect of N and P on net photosynthesis was 22.3% less in an ozone chamber. Net photosynthesis of the seedlings with no fertilization was not affected by ozone treatment. Based on the observed interactions between N, P, and ozone, it was concluded that the stimulatory effect of fertilization on growth of Pinus densiflora would be decreased by ozone treatment, but fertilization would increase resistance to ozone by re-allocation of increased carbohydrates.

• Journal of the Korean Wood Science and Technology
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• v.52 no.3
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• pp.289-299
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• 2024

The current study aimed to investigate the impact of CO₂ enrichment on the width of annual tree rings, earlywood and latewood, and the area of annual growth of Pinus densiflora Siebold & Zucc. grown in open-top chamber (OTC). To this end, two CO₂ enrichment cases were considered, namely 1.4 × increment (560 ppm in OTC-II) and 1.8 × (720 ppm in OTC-III) were compared with the current atmosphere (400 ppm in OTC-I). The CO₂ enrichment conditions for a period of 12 years (2010-2021) were considered, and all measurements were done through image analysis. The study showed that the increment in CO₂ concentrations positively affected the tree growth. The measurement data from the trees in OTC-III were considerably higher than those from OTC-I, whereas those from OTC-II were slightly higher than those from OTC-I. Decreasing patterns of the measured widths and area in 6-7 years after the beginning of CO₂ enrichment was found for all the OTCs. These patterns were possibly due to changes in the physiological features, such as aging. The findings of the present study can have potential uses as fundamental data for forest management considering CO₂ concentrations.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.3
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• pp.183-188
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• 2021

The increase in temperature due to climate warming is predicted to affect crop yields in the future. Until now, various types of OTC (open top chamber) that simulate the future climate condition have been developed and used to study the effect of temperature increase due to global warming on maize growth. However, in most OTCs, high equipment and maintenance costs were required to artificially increase the temperature. This study was carried to develop a cost-effective and simple OTC suitable for climate warming experiments for forage maize. Three octagonal OTCs with a height of 3.5 m × a diameter of 4.08 m and a partially covered top were constructed. The lower part of OTC covered film was opened at a height of 26 cm (OTC-26), 12 cm (OTC-12) from the ground surface, or not opened (0 cm, OTC-0). Mean air temperatures during the daytime on a sunny day in OTC-0, OTC-12 and OTC-26 increased to 3.23℃, 1.33℃, and 0.89℃, respectively, compared to the ambient control plot. For a pilot test, forage maize, 'Gwangpyeongok' was grown at OTCs and ambient control plots. As a result, in the late maize vegetative growth phase (July 30), the plant height was increased more than 45% higher than the ambient control plot in all OTC plots, and the stem diameter also increased in all OTC plots. These results indicate that it is possible to set the temperature inside the OTC by adjusting the opening height of the lower end of the OTC, and it can be applied to study the response of forage maize to elevated temperature. An OTC, with its advantages of energy free, low maintenance cost, and simple temperature setting, will be helpful in studying maize growth responsiveness to climate warming in the future.

• Advances in environmental research
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• v.3 no.4
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• pp.355-365
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• 2014

The present study has been performed on one year old tree saplings of Azadirachta indica (L.), Cassia siamea (L.), Dalbergia sissoo (Roxb.), Eucalyptus rostrata (L.), Mangifera indica (L.) and Schyzygium cumini (L.) in order to assess the effect of exposure of $SO_2-NO_2$, alone and combination of two gases. Tree saplings have been exposed to an average of $495{\mu}g\;m^{-3}$ $SO_2$ and $105{\mu}g\;m^{-3}$ $NO_2$ for 40 d at the rate of $4hd^{-1}$ during 10:00 am to 01:00 pm in OTC. Total chlorophyll, specific leaf area (SLA), nitrate reductase (NR) activity, foliar protein, free proline content and free amino acids (AAs) of foliage have been the plant parameters, taken into consideration to evaluate the effect of gaseous exposure. Exposure of two gases has caused reduction in total chlorophyll content (P < 0.05, 0.01). Physiological and biochemical process has been seemed to be altered noticeable due to the combined effect of $SO_2+NO_2$ followed by $SO_2$ alone (P < 0.05, 0.01). $NO_2$ mediated stress has produced, stimulatory and inhibitory responses in tree saplings. Results reveal that tree saplings have been attempted to absorb the $NO_2$ through N assimilation pathway. E. rostrata, C. siamea have been emerged as moderate tolerant to $SO_2$ mediated stress followed by A. indica. Response pattern of S. cumini, M. indica and D. sissoo set them as good indicators of $SO_2-NO_2$ exposure. Effects of two gases on tree saplings have been found to be synergistic.

• Journal of Korean Society of Forest Science
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• v.89 no.1
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• pp.105-115
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• 2000

This study was conducted to test a hypothesis that sensitivity of trees to ozone exposure was related to their growth rates. Two cultivars of Populus alba ${\times}$ P. glandulosa with different genetic growth potential were used for the comparison. Two clones(72-30, 72-16) of cultivar No. 4 with fast growing potential and three clones(71-28, 72-27, 72-19) of cultivar No. 2 with slow growing potential were propagated in early spring by cutting in $2-{\ell}$ plastic pots. They were grown outdoor for 5 months and exposed in late August for 30 days to 70 and 130ppb ozone in a open-top chambers(2.5m in diameter and 2m in height). Ozone concentration in a control chamber was maintained below 30ppb by filtering with activated charcoal. Each treatment was replicated twenty times. In a control chamber, cultivar No. 4 grew 73%, 64%, and 38% faster than cultivar No. 2 in leaf weight, root weight, and total dry weight, respectively. Visible injury was observed only in cultivar No. 4 in 130ppb treatment. Ozone treatment at both 70 and 130ppb decreased height growth, dry weight of leaf, root, and entire plants in all five clones. Particularly root growth was reduced by 39.7% and 13.8% in cultivar No. 4 and No. 2, respectively, in 70ppb treatment. Consequently, shoot/root ratio of cultivar No.4 was increased by 63.4%, while that of cultivar No.2 was increased by 22.1%. Stomatal conductance decreased more in cultivar No.4 than in cultivar No.2. Net photosynthesis of cultivar No.4 at 130ppb ozone decreased by 69.5%, while that of cultivar No.2 decreased by 31.5%. Above mentioned physiological responses of two cultivars to ozone strongly suggested that fast growing cultivar No.4 was more sensitive to ozone than slow growing cultivar No.2. It was concluded that sensitivity of trees to ozone exposure was closely related to their growth rates.

• The Korean Journal of Ecology
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• v.22 no.2
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• pp.79-83
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• 1999

Phytotoxic effects of ozone and ethylenediurea (EDU) on soybean (Glycine max) and spinach (Spinacia oleracea) were observed by using open-top field chamber system (OTC). Gas exchange rates (photosynthesis. stomatal conductance and transpiration rates) of soybean plants were decreased by 20% to 30% by ambient ozone and resulted in 30% reduction of seed yields. In OTC. ambient ozone and 0.12 $\mu$l/l $O_3$ decreased gas exchange rates of spinach by 25% to 40% and by 50%. respectively. The protective effect of EDU against ozone induced injury was obtained at 100 mg/l on soybean. and at 250 mg/l on spinach, respectively. The excessive application of EDU. however. inhibited photosynthesis. transpiration. and stomatal conductance without any specific visible damage.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2018.06a
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• pp.77-78
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• 2018