• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.1-6
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• 2001

Many researchers have been studied with guard cell protoplasts and detached epidermis as they think that properly stabilized protoplasts and detached epidermis retain many of the properties of intact guard cells. However, some studies have shown that stomata in detached epidermis behave differently, both quantitatively and qualitatively, from those in the intact leaf. Stomata in the intact leaf are very sensitive to environmental factors such as light, $CO_2$ and osmotic stress, but stomata in detached epidermis are less sensitive to these factors than those in the intact leaf. The clearest evidence to suggest the different response between detached epidermis and intact leaf obtained from the experiments with heavy metal, cadmium. 3-weeks old Commelina. communis was transferred to and grown in Hoagland solution in the presence or absence of 5 mM $Cd^{2+}$ for 4 days. The application of $Cd^{2+}$ showed about 70% inhibition of stomatal conductance when measured at various light intensity (100-1,000 $\mu$mole $m^{-2}s^{-1}). However, stomata in detached epidermis floated on an incubation medium containing 100 $\mu$M $Cd^{2+}$ opened to a degree of about 8.38 fm, but the stomata treated with no cadmium opened to 3.74 ${\mu}{\textrm}{m}$. These results were unexpected as the intact leaf grown in a Hoagland solution containing cadmium showed very negative physiological responses. These results showed that stomata in detached epidermis and in the intact leaf could respond reversely. Therefore, it is possible that we now misunderstand how stomata open in real natural condition.

• Journal of Climate Change Research
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• v.34 no.22
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• pp.8813-8828
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• 2021

Stomatal closure is a major physiological response to the increasing atmospheric carbon dioxide (CO₂), which can lead to surface warming by regulating surface energy fluxes-a phenomenon known as CO₂ physiological forcing. The magnitude of land surface warming caused by physiological forcing is substantial and varies across models. Here we assess the continental warming response to CO₂ physiological forcing and quantify the resultant climate feedback using carbon-climate simulations from phases 5 and 6 of the Coupled Model Intercomparison Project, with a focus on identifying the cause of intermodel spread. It is demonstrated that the continental (40°-70°N) warming response to the physiological forcing in summer (~0.55 K) is amplified primarily due to cloud feedback (~1.05 K), whereas the other climate feedbacks, ranging from -0.57 to 0.20 K, show relatively minor contributions. In addition, the strength of cloud feedback varies considerably across models, which plays a primary role in leading large diversity of the continental warming response to the physiological forcing.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.130-134
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• 2016

How does $CO_2$ affect on the stomatal mechanism? The mechanism of stomatal opening by $CO_2$ is not clear as it is difficult to see $CO_2$ effect on light-induced stomatal opening. Furthermore, stomata may react differently according to the concentration of $CO_2$. The significance of the possible endogenous rhythms must consider to understand on $CO_2$-related response. It is clear that $CO_2$ has an effect on the accumulation of osmotic materials which determines the degree of stomatal apertures because it is known that stomata open in the condition of the reduced $CO_2$ concentration. However, it is not fully understood how $CO_2$ leads to the stomatal opening. It has been thought that $CO_2$ can not affect on the ion fluxes which determines the increase of osmotic potential in guard cells. However, in this study, the changes of guard cell membrane permeability by $CO_2$ have been focused on. There are many reports that $CO_2$ related reactions are dominant when the leaf is exposed to certain a mount of $CO_2$. The hypothesis of the stomatal opening by light is based on the increase of osmotic materials in guard cells including $K^+$, $Cl^-$, sucrose and $malate^{2-}$. It was reported that $CO_2$ induced a big hyperpolarization indicating that $H^+$ was extruded to the cell outside. It was also found that $CO_2$ caused guard cell membrane hyperpolarization in the intact leaf up to 3 or 4 times higher than that of light induced membrane hyperpolarization. These results represent that $CO_2$ can affect on the change of physical characteristics which affects on the change of the membrane permeability.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.77-84
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• 2016

Seedling stage is particularly important for tree survival and is easily influenced by warming. Therefore, air temperature being increased due to climate change may affect physiological traits and growth of seedlings. This study was conducted to investigate the physiological and growth responses of Larix kaempferi seedlings to open-field experimental warming. 1-year-old and 2-year-old L. kaempferi seedlings were warmed with infrared lamps since April 2015 and April 2014, respectively. The seedlings in the warmed plots were warmed to maintain the air temperature to be $3^{\circ}C$ higher than that of the control plots. Physiological responses (stomatal conductance, transpiration rate, net photosynthetic rate and total chlorophyll content) and growth responses (root collar diameter (RCD), height and biomass) to experimental warming were measured. Physiological and growth responses varied with the seedling ages. For 2-year-old L. kaempferi seedlings, stomatal conductance, transpiration rate and net photosynthetic rate decreased following the warming treatment, whereas there were no changes for 1-year-old L. kaempferi seedlings. Meanwhile, total chlorophyll content was higher in warmed plots regardless of the seedling ages. Net photosynthetic rate linked with stomatal conductance also decreased due to the drought stress and decrease of photosynthetic efficiency. In response to warming, RCD, height and biomass did not show significant differences between the treatments. It seems that the growth responses were not affected as much as physiological responses were, since the physiological responses were not consistent, nor the warming treatment period was enough to have significant results. In addition, multifactorial experiments considering the impact of decreased soil moisture resulting from elevated temperatures is needed to explicate the impacts of a wide range of possible climate change scenarios.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.221-227
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• 2005

The effects of light and $CO_2$ on the electrophysiological characteristics of guard cells in the intact leaf and isolated epidermis have been investigated. Fast hyperpolarization of guard cell apoplastic PD in the intact leaf was recorded reaching up to around 7 mV and 20 mV in response to light and $CO_2$. Whenever the experiments were attempted with isolated epidermis, there was no response to light and $CO_2$. In order to determine the influence of the mesophyll cells, the apoplastic PD of guard cells in isolated epidermis was measured in the presence of the mesophyll supernatant or the control medium. The apoplastic PD in isolated epidermis was hyperpolarized to -7mV, changing from -22mV to -29mV at 40 min. But, when isolated epidermis was incubated with the supernatant from mesophyll cells incubated in the light, the apoplastic PD in isolated epidermis was hyperpolarized to -19 mV, changing from -22 mV to -40.5 mV. $CO_2$ also caused a change of 0.1 to 0.3 pH unit in the intact leaf. However, this change was absent in isolated epidermis. A vibrating probe was used to detect the change in electrical currents at the surface of excised intact leaves and isolated epidermis. The reading of excised intact leaves in the dark was $0.5\muA\;cm^{-2},$ remaining steady until illuminated. Light increased the current on the surface of excised leaves to about $0.8\muA\;cm^{-2},$. However, light had no effect in the current on the surface of isolated epidermis. Apoplastic pH changes across the stomatal complex in response to light and dark were measured both in the intact leaves and isolated epidermis over the same time period using pH micro-electrodes. The guard cell wall of intact leaf was acidified to 2.5 pH unit, falling from pH 7.5 to pH 5.0 in the first 10 min. in the light. At the same time the guard cell wall pH of isolated epidermis fell from pH 7.5 to pH 7.0 at 10 min. The guard cell wall pH of isolated epidermis incubated in the mesophyll supernatant fell from pH 7.6 to pH 6.7 at 10 min. Likewise, It could be imagined that an electrical signal, chemicals and hormones propagated from the mesophyll in response to light and $CO_2$ could control a fast stomatal response.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.1
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• pp.35-42
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• 1998

We compared absorption and adsorption rates of air pollutants by plants to eveluate the difference of absorption capacity of plant species and kinds of air pollutants, when foilage plants were exposed to $O_3$ and $SO_2$ singly and combiningly. Absorption and adsorption rates of three foliage plants exposed to $O_3$ and $SO_2$ singly and in combination varied a little according to plant species and kinds of air pollutants. But total absorption rate of Spathiphyllum patinii and Ficus benjamina was higher, and it was lower in Pachira aquatica. When exposed to $O_3$ and $SO_2$ at the same concentration, Pachira aquatica absorbed more $O_3$ than $SO_2$, in contrast to Ficus benjamina absorbing more $SO_2$. On the other hand, Spathiphyllum patinii absorbed as much $O_3$ as $SO_2$. Physiological activities were measured since absorption rates were affected by physiological characteristics of plants. Spathiphyllum patinii and Ficus benjamina showed higher photosynthetic and transpiration rates, and Pachira aquatica showed lower values. And diffusive and stomatal resistences of Pachira aquatica were higher than those of two other species. These results showed that absorption capacity was affected by the differences of physiological characteristics. Absorption capacity of air pollutants increased in plants, such as Spathiphyllum patinii and Ficus benjamina, which had high $SO_2$ absorption rate. We found that plants showing high $CO_2$ absorption rates absorb a lot of air pollutnats.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.2
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• pp.79-89
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• 2018

Subsurface drip irrigation (SDI) system is considered one of the most effective methods for water application. A 2-year field study was conducted to investigate the effect of SDI systems with various dripline spacing (0.7 or 1.4 m) and position (under furrow or ridge) on soybean (Glycine max L.) production at a sandy-loam soil in Miryang, South Korea. For 2016-2017, average grain yield in SDI irrigated plots, $3.16Mg\;ha^{-1}$, was statistically greater than rainfed irrigated plot ($2.63Mg\;ha^{-1}$). Soybean grain yield averaged $3.25Mg\;ha^{-1}$ for the 0.7 m dripline spacing and $3.07Mg\;ha^{-1}$ for the 1.4 m spacing for the two-year period compared to a rainfed irrigated average of $2.63Mg\;ha^{-1}$ for the same period. Soybean treated with SDI system had significantly greater values of normalized difference vegetation index and stomatal conductance, indicating that soybean plants in SDI plots had greater photosynthetic and stomatal activity due to the higher water availability in soil. Irrigation water use efficiency (IWUE) was greatest in the plot of 0.7 m spacing installed under ridge position than any other plot across growing season. Average soil water content in plots with 0.7 m dripline spacing was $0.21m^3\;m^{-3}$ at 5 cm depth layer, which was 45% greater compared to the plots with 1.4 m spacing, even though the gross irrigation amounts were greater in 1.4 m spacing plots. It is concluded that wide dripline spacing (1.4 m) is probably the more economical installation design for SDI system compared to 0.7 m spacing in this study soil because the initial cost for dripline may be reduced with wide spacing design, even though the IWUE is greater in the plot of 0.7 m dripline spacing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.2
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• pp.146-152
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• 1997

Development of shoot and root, leaf water potential and photosynthetic rate affected by water stress in early growing stage of tobacco were surveyed to interpret stress response in terms of plant physiological and agricultural aspects. The growth of shoot and root was highly suppressed by water stress and the difference in dry weight by rewatering was smaller in root than in shoot. The total root length was highly decreased by water stress and the lengths of root for water stress and non-stress were 74m and 84m, respectively, after rewatering. The root growth treated by water stress was increased between 2nd and 3rd day after treatment indicating that temporary water stress at early growing stage might have increased of root zone activity for early growth stage. The leaf water potentials were decreased to -7.63MPa, -9.47MPa, -11.89MPa, -13MPa at the 2nd, 3rd, 4th and 5th day by water stress. The relative water contents were 75%, 62% and 57% at the 3rd, 4th and 5th day after treatment. Photosynthesis was reduced largely by water stress. The photosynthetic rate after treatment at 2nd day and 3rd day was dropped to 18.15$\mu$mol. $CO_2$/$m^2$ㆍsec$^{-1}$ and 9.35$\mu$mol. $CO_2$/$m^2$ㆍsec$^{-1}$. It was never recovered to the normal, even after rewatering. Stomatal conductance had been reduced since 2nd day after treatment and increased after rewatering.

• Asian Journal of Atmospheric Environment
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• v.6 no.4
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• pp.259-267
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• 2012

To clarify the effects of black carbon (BC) particles on growth and gas exchange rates of Asian forest tree species, the seedlings of Fagus crenata, Castanopsis sieboldii, Larix kaempferi and Cryptomeria japonica were exposed to BC particles with sub-micron size for two growing seasons from 1 June 2009 to 11 November 2010. The BC particles deposited after the exposure to BC were observed on the foliar surface of the 4 tree species. At the end of the experiment, the amount of BC accumulated on the foliar surface after the exposure to BC aerosols were 0.13, 0.69, 0.32 and 0.58 mg C $m^{-2}$ total leaf area in F. crenata, C. sieboldii, L. kaempferi and C. japonica seedlings, respectively. In August 2010, the exposure to BC particles did not significantly affect net photosynthetic rate under any light intensity, stomatal diffusive conductance to water vapour ($g_s$), stomatal limitation of photosynthesis, response of $g_s$ to increase in vapour pressure deficit and leaf temperature under light saturated condition in the leaves or needles of the seedlings. These results suggest that the BC particles deposited on the foliar surface did not reduce net photosynthesis by shading, did not increase leaf temperature by absorption of irradiation light, and did not induce plugging of stomata in the leaves or needles of the seedlings. There were no significant effects of BC particles on the increments of plant height and stem base diameter during the experimental period and the whole-plant dry mass at the end of the experiment. These results indicate that the exposure to BC particles with sub-micron size for two growing seasons did not significantly affect the growth and leaf or needle gas exchange rates of F. crenata, C. sieboldii, L. kaempferi and C. japonica seedlings.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.143-150
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• 2009

Deicing salt is used to melt snow and ice on the road for traffic safety during the winter season, which accumulates in the roadside vegetation and induces visible injuries. The damage may accelerate particularly when it coincides with early spring leaf out. In order to better understand the response mechanisms, C. kousa (3-year-old) was irrigated twice prior to leaf bud in a rhizosphere with solutions of 0.5, 1.0, and 3.0% calcium chloride ($CaCl_2$) concentration, that were made by using an industrial $CaCl_2$ reagent practical deicing material in Seoul. Physiological traits of the mature leaves were progressively reduced by $CaCl_2$ treatment, resulting in reductions of total chlorophyll contents, chlorophyll a:b, photosynthetic rate, quantum yield, stomatal conductance, $F_V/F_M$, and NPQ. On the contrary, light compensation point and dark respiration were increased at high $CaCl_2$ concentration. A decrease in intercellular $CO_2$ concentration by stomatal closure first resulted in a reduced photosynthetic rate and then was accompanied by low substance metabolic rates and photochemical damage. Based on the reduction of physiological activities at all treatments ($CaCl_2$ 0.5%, 1.0%, and 3.0%), C. kousa was determined as one of the sensitive species to $CaCl_2$.