• The Korean Journal of Ecology
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• v.18 no.2
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• pp.265-273
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• 1995

Net photosynthetic rate (Pn) of Quercus mongolica leaves was determined under the controlled O₃concentrations of 0, 20, 30, 40, 50 or 60 ppb at every 10 min for 7 hr. Under the fumigation of the different O₃concentrations the relative net photosynthetic rate (RNPR) of the leaves decreased rapidly until 1 hr and thereafter decreased slowly. At below 20 ppb O₃the decrease of the RNPR was scarce but at above 20 ppb O₃the RNPR was inversely proportional to O₃concentration on a logarithmic curve. The RNPR at 60 ppb O₃, for example, was reduced 30％ less than that without O₃. Under the different O₃concentrations fumigated for the short period of time the Pn dependent upon PPFD was depicted as saturation equation and Pn dependent upon temperature as quadratic equation. Results of this study suggest that short-term low O₃of less than 60 ppb concentration may lead to reductions of Pn in Q. mongolica leaves.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.3
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• pp.220-226
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• 2005

We investigated the effect of $O_3$ on the photosynthetic characteristics of oriental plane (Platanus orientalis L.) that is used as a side tree or ornamental tree in Korea. Two-year-old oriental plane seedlings were transplanted to pots and transferred into a closed $O_3$ chamber, Photosynthetic pigment content and photosynthetic characteristics of leaves were measured every three weeks during 100 ppb $O_3$ fumigation. There was no visible foliar injury by $O_3$ exposure and the content of photosynthetic pigments did not show significant differences between control and $O_3$-treated seedlings. But photosynthetic rate, stomatal conductance, and water use efficiency in leaves of $O_3$-treated seedlings were reduced after six weeks of ozone fumigation. In addition, reduction of carboxylation efficiency and photochemical efficiency was observed in leaves of $O_3$-treated seedlings after three weeks and six weeks. In accordance with our results, carboxylation efficiency, the most sensitive parameter to $O_3$ stress, was considered to be a suitable indicator of $O_3$ sensitivity.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.214-217
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• 2011

Fumigant, methyl bromide which is used in most countries for plant quarantine, has been designated and under control as ozone depleting substance. For developing alternative chemicals for methyl bromide, many countries have been intensifying their capacity. This study was carried out to investigate the residue patterns of hydrogen cyanide which is commonly used for plant quarantine. Hydrogen cyanide was treated onto the orange, banana, and pineapple at recommended and double doses and then sampling was done at 1 and 3 day after fumigation treatment. Residue of hydrogen cyanide was found safe because average residue levels on orange, banana, and pineapple after 3 days of fumigation treatment were $0.57{\pm}0.05$, $0.21{\pm}0.17$, and $0.41{\pm}0.08$ ppm, which were lower than the MRLs of Korea (5 ppm), Japan (5 ppm), USA (50 ppm), and Canada (25 ppm). Hydrogen cyanide are expected to be used as alternative chemicals for methyl bromide fumigant for orange, banana, and pineapple.

• Korean Journal of Agricultural Science
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• v.19 no.2
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• pp.161-169
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• 1992

Studies were conducted to examine the effects of single or combined treatment of uniconazole [(E)-1-(4-chlorophenyl)-4, 4-dimethyl 2(1, 2,-4-triazol-1-yl)-1-penten-3-ol)] and silver thiosulfate (STS) on reducing ozone injury to snap beans (Phaseolus vulgaris L. 'Strike'). Two weeks after seeding, plants were given a soil drench of uniconazole(XE-1019) solution at concentrations of 0.001, 0.005 and 0.025 mg/pot, and then two days prior to ozone fumigation, 0.3 and 0.6 mM STS containing 0.01% Tween-20 were also sprayed. Uniconazole was effective in providing protection against ozone injury through increase activities of free radical scavengers such as superoxide dismutase (SOD) and peroxidase (POD) as well as the increase of chlorophyll content and stomatal resistance resulted from plant growth retardation. The phytoprotective effects of STS seemed to be related to its properly of blocking the ethylene action and increasing activities of SOD and POD. Even at low concentrations, a combined treatment with uniconazole drench, STS spray significantly reduced ozone injury compared to single application.

• Journal of Conservation Science
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• v.25 no.3
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• pp.283-291
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• 2009

Methyl Bromide that was used as fumigation gas turned out to be the substance of destroying the ozone layer. For that reason, at the Montreal Protocol in 1987 the use of methyl bromide was forbidden starting 2005 in the advanced country. Also according to the 2007 Bali Protocolly methyl bromide is expected to be forbidden and therefore the purpose of this study is to find out the effects of substitution fumigation gas (Ethylene Oxide+HFC 134a, Methyl Iodide, Cyanogen and Argon) on the metal(silver, copper and iron), wood(oregon pine), pigment(yellow, red, blue, white and black), textile(hemp, ramie, jute, silk1 and silk2 / indigo, safflower and cork) and paper. After the fumigation test, ethylene oxide+HFC 134a did not have changes in the weight and color of the material itself before and after the experiment. On exterior alteration, color change occurred partly on paper and metal. Also, in most materials color change extent was 0.5 to 1.5 on the average and showed scanty difference. The materials after the fumigation test with methyl iodide did not show weight changes after the test. However, color changes more than 1.0 was shown in most of the materials especially in dyed textile material. In blue pigment, the discoloration on the surface could be seen by naked eyes. Fumigation test with cyanogen gas did not show weight changes and discoloration is more than 1.5 before and after the test. The weight changes of test materials with the argon gas was decreased about 3 to 6%. It can be observed that discoloration on paper was generated. Color changes can be seen on jute dyed with safflower and cork for two weeks with argon gas and the extent was 6.3 and 6.0.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.2
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• pp.119-126
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• 1991

Air pollution is directly and indirectly associated with the toxicology through the increase of mortality, the decrease of oviposition rate, and the decline of insect population, as well as the disruption of equilibria with higher or lower trophic levels. To investigate intrinsic decrease rates, oviposition period, and emerging rates of pupae of house fly under air pollution stresses, healthy individuals of Musca domestica L. were collected in the field, cultured in the laboratory for 2 $\sim$ 3 generations, and artificially exposed to $O_3 (4 ppm) in automatically controlled air pollutant fumigation chambers. Results from this study are summarized as follows: 1. Survivorship curves of both control group and exposed groups of healthy house fly to 4 ppm $O_3$ have linearly or stair-like decreasing trends of revers S-shape. 2. For cohorts exposed to 4 ppm of $O_3$, intrinsic decrease rate of cohort exposed for 2 hours significantly increases compared to that of control group, slight increases were observed for those exposed for 4 hours and 8 hours, which shows no distinct relationships between exposure period and intrinsic decrease rate. 3. While the numbers of pupae of exposed cohorts increase with the increase of exposure period, emerging rate shows a distinct decrease. 4. The relationships between emerging rate (E) of pupae and the exposure period (T) for cohorts exposed to 4 ppm of $O_3$ are expressed with the equation, E (%)=21.027 - 7.942 ln (T).

• Journal of Environmental Science International
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• v.18 no.12
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• pp.1325-1330
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• 2009

The fumigant 1,3-dichloropropene (1,3-D) was recently proposed as a direct replacement for methyl bromide ($CH_3Br$) in soil fumigation. This study was conducted to better understand behavior phase partitioning, diffusion and volatilization of 1,3-D as affected by isomer. The Henry's law constant(KH) of cis-1,3-D and trans-1,3-D was 0.058 and 0.037 at $20^{\circ}C$, respectively. $K_H$ of cis form of 1,3-D was higher than that of trans form of 1,3-D. To compare with volatilization of 1,3-D isomer, soil column [70 cm (length)${\times}$12 cm (i.d.)] included a shank injection at 30 cm with 300 kg $ha^{-1}$. Maximum cis-1,3-D and trans-1,3-D concentration reached 57 mg $L^{-1}$ and 39 mg $L^{-1}$ at 30 cm depth at 1h after application. Cumulatively, after 10 days, 51.8% and 43.57% of applied cis-1,3-D and trans-1,3-D was emitted via volatilization, respectively. The total losses of cis-1,3-D were significantly greater than that of trans-1,3-D. Finally, cis-1,3-D and trans-1,3-D, such as isomer are dominant of 1,3-D fates in soil.

• The Korean Journal of Ecology
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• v.24 no.2
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• pp.93-100
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• 2001

One-year-old cottonwood (Populus deltoides Bartr.) clones, which were classified as sensitive or tolerant, were exposed to 150 n1/1 ozone (O$_3$) over 8 days for 8 hours each day under glass chamber conditions with natural sunlight. The leaves of the sensitive clone had black stipple and bifacial necrosis after $O_3$ treatment. Photosynthesis and stomatal conductance were measured before, during, and after the $O_3$ treatment. The photosynthetic rates due to $O_3$ treatment were decreased 51 percent and 34 percent on the sensitive and tolerant clone, respectively. The stomatal conductance of the sensitive clone was more than 40 percent higher than that of the tolerant clone regardless of the $O_3$ treatment. As light intensity increased, the $O_3$ effect on photosynthesis was clear. Compared to the previous growth chamber studies, our natural light exposure system was able to maintain a stable photosynthetic responses of the control treatment throughout the fumigation period. In addition, changes in assimilation versus intercellular $CO_2$ concentration (A/C curves) showed that $O_3$ decreased the slope and asymptote of the curves for the sensitive clone. This indicates that $O_3$ decreases the biochemical capacity of photosynthesis on the sensitive clone. Chlorophyll contents and fluorescence of the two clones were analyzed to examine the $O_3$ effects on photosystem 11, but $O_3$ did not impact these variables on either clone. Although the tolerant clone did not show any foliar injury, we could not find any ecophysiological defensive responses to $O_3$ treated. Stomatal conductance of the tolerant clone was originally much lower than that of the sensitive one. Thus, the mechanisms of the tolerant clone in this system are to narrowly open stomata and efficiently maintain photosynthesis with a more durable biochemical apparatus of photosynthesis under $O_3$ stress. The sensitive clone has higher photosynthetic capacity and more efficient light reaction activity than the tolerant one under charcoal filtered condition, but is not as resilient under stress.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.167-174
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• 2000

A glass chamber experiment was conducted to evaluate the impact of ozone (O$_3$) on the physiology of two soybean, Glycine max L. cultivars, 'Hwanggum' and 'Jangyub'. Thirty-day old plants with 1-2 nodes were exposed to $O_3$ of <10 and 150 n1 1$^{-1}$ in the chambers for 8 h d$^{-1}$ for 3 days. Net photosynthesis, stomatal conductance, chlorophyll a, chlorophyll b and total chlorophyll contents, and foliar injury (% injured leaves) were measured. Although foliar damage was more severe on Jangyub than on Hwanggum, net photosynthesis was decreased by 60% on Hwanggum and 13% on Jangyub due to the $O_3$ treatment. Stomatal conductance on Jangyub was twice higher than that on Hwanggum and it was not changed by the $O_3$ treatment. Whereas, stomatal conductance on Hwanggum was 60-80% decreased by $O_3$, Chlorophyll contents did not change due to the $O_3$ treatment or variety. We can conclude that the reduction of net photosynthesis by $O_3$ was mainly due to the decreases of stomatal conductance and Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) activity on dark reaction. And foliar injury and chlorophyll content did not contribute to the net photosynthetic decrease. The gas-exchange variables measured 24 h after the termination of $O_3$ fumigation showed that there was no significant recovery within a day. Since the physiological responses on Jangyub were not much affected by the $O_3$ treatment, this variety could be $O_3$ resistant.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.45-45
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• 2017

The Indian meal moth, Plodia interpunctella, is one of the most important pests of stored food in the food processing industry worldwide. To control the Indian meal moth, methyl bromide, phosphine, high carbon dioxide, sulfuryl fluoride and plant essential oil fumigation have been considered. However, these treatments have disadvantages. For example, depleting the ozone layer, showing resistance in insect, low control efficacy or need high cost for treatment. Chlorine dioxide ($ClO_2$) is strong disinfectant and insecticide. The gas caused a malfunction in enzymes. The oxidative stress induced by $ClO_2$ gas treatment damaged to a physiological system and all life stages of P. interpunctella. The gaseous $ClO_2$ is a convincing alternative to methyl bromide for controlling P. interpunctella. The gaseous $ClO_2$ was generated by a chlorine dioxide generator (PurgoFarm Co., Ltd., Hwasung, Korea). It generated highly pure $ClO_2$ gas and the gas blown out through a vent into a test chamber. Gas entry to the chamber was automatically controlled and monitored by a PortaSene II gas leak detector (Analytical Technology, Collegeville, PA, USA). The properly prepared eggs, larvae, pupae, and adults of P. interpunctella were used in this experiment. Data were analyzed using SAS 9.4. Percentage data were statistically analyzed after arcsine-root transformation. Analysis of variance was performed using general linear model, and means were separated by the least significant difference test at P < 0.05. Fumigation is an effective management technique for controlling all stages of P. interpunctella. We found that $ClO_2$ gas treatment directly effects on egg, larvae, pupae and adults of P. interpunctella. The gas treatment with proper concentration for over a day achieved 100 % mortality in all stages of P. interpunctella and short time treatment or low concentration gas treatment results showed that the egg hatchability, pupation rate, and adult emergency rate were lowered compare with untreated control. Also, abnormal pupae or adult rate were increased. Gaseous $ClO_2$ treatment induced insecticidal reactive oxygen species (ROS), and it resulted in fatal oxidative stress in P. interpunctella. Taken together, these results showed that exposure proper concentration and time of the gas control all stages of P. interpunctella by inducing fatal oxidative stress. Further studies will be required to apply the gas treatment under real-world condition and to understanding physiological reaction in P. interpunctella caused by oxidative stress.