• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.45-50
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• 1981

Diurnal changes in leaf stomatal resistances were measured on leaf positions and both surfaces to investigate the stomatal response to irradiance in wheat, var. Chokwang and barley, var. Dongbori 1. Stomatal frequency and size were also determined to explain the control mechanism of gas exchanges in two species. The leaf diffusive resistances of two species decreased, as the sun rose, to minimum at 10 to 11 o'clock a.m. and increased gradually in the afternoon, even faster at sunset. As the adaxial irradiance increased, stomatal resistances decreased sensitively in the range of 30uEm$^{-2}$ㆍsec$^{-1}$ to 150uEm$^{-2}$ㆍsec$^{-1}$ quantum flux density. The stomatal opening of the abaxial surface began at lower irradiance and was completed earlier than the adaxial surface. The adaxial irradiances decreased in order of leaf position, flag, the 2nd, the 3rd leaf, and the stomatal resistances increased in the same order. Even under the same irradiance, the stomatal resistance of lower leaves were higher than those of upper leaves. The stomatal frequencies of lower leaves were less, but the stomatal size was greater than those of upper leaves. Consequently, the relative leaf area occupied by stomatal pores were constant among leaf positions in two species.

• Journal of Environmental Science International
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• v.6 no.2
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• pp.125-131
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• 1997

The mechanism of stomatal closing in response to $O_2$ was indirectly investigated by using $H_2O_2$ which is the intermediate product of $O_2$ metabolites. Stomata in epidermal strips close in response to $H_2O_2$. The effect of $H_2O_2$ on stomatal closing was dependent on the concentration of $H_2O_2$. 10 ppm $H_2O_2$ showed a clear effect on stomatal closing and 1000 ppm $H_2O_2$ induced complete stomatal closing after the treatment of 3 hours. Stomatal closing by $H_2O_2$ in intact leaf was also observed by measuring the diffusion resistance with porometer. It was found that the stomatal closing by $H_2O_2$ was not mediated by $Ca^{2+}$, and that was a different result observed in stomatal closing by water stress. Reversely, $Ca^{2+}$ showed a great inhibition on stomatal closing. The leakage of K+ in epidermal strips was doubled in response to $H_2O_2$ when it was campared to the control. 10 ppm $H_2O_2$ decreased photosynthetic activity. Fv/Fm representing the activity of Photosystem II was reduced about 4 % in 10 ppm $H_2O_2$ and 8 % in 100 ppm $H_2O_2$ In the treatment of 1.5 hour. However, stomatal closing by 10 ppm $H_2O_2$ was reduced about 56 %. According1y, it can be suggested that stomatal closing by $H_2O_2$ is related with the decrease of photosynthetic activity, but it was chiefly induced by the change of the membrane permeability. Key words Commelina communis, stomatal closing, $H_2O_2$, $Ca^{2+}$, photosynthesis.

• Animal cells and systems
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• v.4 no.4
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• pp.337-340
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• 2000

The photosynthetic and stomatal responses of several woody plants (Powlonia coreana, Firmiana simplex, Quercus acutissima Q. variabilis and Q. serrata) to SO$_2$ were investigated in order to understand their ecophysiological tolerance to $SO_2$ Of the plants, P, coreana showed the largest reduction in its photosynthesis in response to exposure of 0.4 ppm $SO_2$ for 20 h. Fumigation of 0.7 ppm $SO_2$ for 20 h caused complete leaf necrosis of P. coreana and f simplex, which made them unavailable for the measurement of photosynthesis. Q. variabilis exhibited the smallest reduction in photosynthesis following exposure of 0.7 ppm $SO_2$ for 20 h. Both stomatal- and non-stomatal inhibition of the plants by $SO_2$ were determined according to equations by lkeda et at. (1992). When exposed to 0.4 ppm $SO_2$ for 20 h, F. simplex and P. coreana showed the lowest stomatal and non-stomatal inhibition, respectively, while Q. variabilis and Q. serrata exhibited the lowest stomatal and non-stomatal inhibition, respectively, in response to 0.7 ppm $SO_2$ for 20 h. The data are discussed with regard to resistance mechanisms of other plants to $SO_2$ exposure and implications for restoration of declined Korean forests.

• The Korean Journal of Ecology
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• v.20 no.2
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• pp.83-94
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• 1997

Stomatal closing by ozone and water stress could reduce further ozone injury by inhibition of ozone influx to the tissue. Direct effect of ozone on stomata can be explained from two aspects which are a stimulation of stomatal closing and an inhibition of stomatal opening. An increase of $Ca^{2+}$ influx into cytoplasm by ozone could stimulate potassium efflux ion channel and inhibits inward potassium ion channels. By this mechanism ozone could induce stomatal closing. On the other hand, ozone could inhibit stomatal opening by affecting the activity of $H^{+}$ dependent ATPase of the membrane in guard cells. This would inhibit proton efflux which precede stomatal opening. It is also possible that ozone could reduce the activity of photosynthesis in guard cells which lead to affect the production of osmotically active sugars and energy. Indirect effect of ozone to stomata is through the effect of $CO_2$ elevation as a result of damage of the photozynthetic machinery. This indirect effect is slower than the direct effect.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.307-314
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• 1984

One hundred winter wheat cultivars obtained from the world collections in Korea were planted in 1982. Stomatal frequency of flag leaf of these cultivars were measured, and among these 21 cultivars which showed different stomatal frequency were selected to investigate the relationship of their stomatal frequencies and other characters such as culm length, heading date and characters related to leaf. Stomatal frequency of flag leaf of 100 cultivars different significantly, ranging from 51 to 90 stomata mm$^{-2}$ for the adaxial and 35 to 65 for the abaxial surfaces of leaf. Stomatal frequency was always greater on the adaxial than on the abaxial surface. Mean ratios (adaxial/abaxial) were 1.5 for the flag leaf and 1.3 for the from second to fouth leaves. Among 21 cultivars examined, stomatal size which measured guard cell length varied from 38.5 to 46.6$\mu$ for adaxial surface and from 39.4 to 49.4$\mu$ for abaxial. A negative correlation was obtained between stomatal frequency and its size. Stomatal frequency decreased from flag (L$_1$) to lower leaves, progresively. Stomatal frequency on L$_1$ sheath was compared to those on L$_3$ and L$_4$ abaxial surface of leaf. More stomatal frequency on top and center of adaxial surface showed than that on basal part of a leaf but the abaxial surface resulted in reverse of adaxial one. Cultivars with high stomatal frequency on flag leaf showed higher stomatal frequency on the other leaves and sheaths. Positive correlation between stomatal frequency and other characters such as, culm length, heading date and chlorophyll content showed statistical significance, whearas it revealed the negative correlation of stomatal frequency with leaf weight, leaf area and stomatal aperture. However, no relation appeared between stomatal frequency and leaf vein.

• Journal of Environmental Science International
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• v.15 no.12
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• pp.1109-1117
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• 2006

To investigate the influence of the mesophyll cells on stomatal opening in response to white light, the segments of isolated epidermis were transferred on partly exposed mesophyll cells of a leaf and stomatal apertures were measured. Transferring the isolated epidermis on partly exposed mesophyll cells of a leaf caused a marked increase on stomatal apertures while stomata in isolated epidermis incubated in MES buffer hardly opened. Mesophyll infiltration with photosynthetic inhibitors (DCMU, DCCD, $NaN_3$) was performed to elucidate the correlation between stomatal apertures and the degree of photosynthetic activity. It was found that transferring the isolated epidermis on partly exposed mesophyll cells of a leaf caused an increase of stomatal apertures depending on the degree of photosynthetic activities. In $NaN_3$ infiltrated leaf discs, transferring the fresh isolated epidermis on partly exposed mesophyll cells of a leaf showed no significant effect, but a slight increase on stomatal apertures. Isolated epidermis alone did not respond to the light properly, but if it was closely contacted with mesophyil cells, the stomata regained the ability of the light response. Therefore, it could be suggested that stomatai apertures were related with the degree of photosynthetic activity in the mesophyll cells.

• Journal of Plant Biology
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• v.30 no.1
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• pp.21-30
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• 1987

The effects of abscisic acid(ABA) spraying for 12 weeks on the stomatal types and frequencies of O. malacophyllus leaves were summarized as follows. ABA inhibited the growth of O. malacophyllus. The prominent effect of ABA on the epidermal structure was the promotion of senescence such as thickness of cell walls, smooth sinuosity of cell walls, and large size of epidermal cells. The stomatal frequency was decreased to 23% by 10$\mu\textrm{g}$ ml-1 ABA and to 48% by 100$\mu\textrm{g}$ml-1, and also the stomatal size was more or less smaller than that of control. The developing secondary stomatal mother cell was not found in both 10 and 100$\mu\textrm{g}$ml-1ABA, but the arrested secondary stomatal mother cell was rarely found in 10$\mu\textrm{g}$ ml-1 ABA. The formation of normal stomatal types such as helico-eumesogenous and aniso-eumesogenous was found in both 10 and 100 $\mu\textrm{g}$ ml-1 ABA asin well as control. Also nine abnormal stomatal types were found, and the frequencies were promoted to 6% by 10 $\mu\textrm{g}$ ml-1 ABA and to 17% by 100 $\mu\textrm{g}$ ml-1 ABA. Among these abnomal stomata, four types such as aborted stomata, single-aborted guard cells, arrested stomata, and modified stomatal complexes were found in control as well as in 10 and 100 $\mu\textrm{g}$ ml-1 ABA, but five types such as wrenched stomata, unequal stomata, wavy guard cells, guard cells overlapped by guard cells, and dissolved cell wall stomata were found in both 10 and 100 $\mu\textrm{g}$ ml-1ABA. The modified stomata complexes were abnormal stomatal types which were newly found and also were varied in types.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.125-132
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• 1995

Studies were made on differences among types and varieties of rice in stomatal density and gas diffusion resistance, and on the relationship between these traits and photosynthetic rate. Significant differences among types and varieties were found stomatal density and gas diffusion resistance. Generally, stomatal density was higher in indica varieties than in Japonica varieties, gas diffusion resistance was lower in the former than in the later, in varieties developed through indica-japonica hybridization it was intermadiate. The stomatal density was closely positively correlated with the gas conductivity and the net photosynthetic rate, was not correlated with single leaf area, and had significant negative correlation with specific leaf weight. Higher photosynthetic rate of indica varieties mainly results from its high stomatal density and low gas diffusion resistance. The result also suggested that high photosynthetic rate might be obtained if the high stomatal density and low gas diffusion resistance in indica could be combined with the larger specific leaf weight in japonica through crossing between two.

• Korean Journal of Medicinal Crop Science
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• v.10 no.2
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• pp.82-87
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• 2002

This study was conducted to investigate the influence of shading treatment on the photosynthetic rate, transpiration rate, stomatal conductance and its any correlations in Liriope platyphylla $W_{ANG}\;et\;T_{ANG}$. Followings were achieved as a conclusion. The net photosynthetic rate was increased as the PAR was increased and reached maximum at the $700-1000{\mu}mol/m^2/s$ of PAR in all of leaves, also this treatment caused a higher net photosynthetic rate in comparison with control. It shows the tendency of increasing stomatal conductance caused by the increment of PAR. The diurnal changes of photosynthesis, transpiration rate and stomatal conductance were increased as the PAR was increased in the morning, but they indicated a decreased tendency in broad day. The relationship between net photosynthetic rate and stomatal conductance is well fit by the first regression linear equation. However, the values obtained from the linear equation have the different, respectively, and have highly significance. From the above results, net photosynthetic rate of shading treatment is higher than control in the same stomatal conductance. Different first regression linear equation were obtained between the transpiration rate and stomatal conductance, photosynthesis and stomatal conductance in during the control and shading treatment, too.

• Asian Journal of Turfgrass Science
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• v.11 no.1
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• pp.23-31
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• 1997

The K+ and Na+ contents in the guard cells of Agave which had a characteristic of CAM plant were measured by using "Rolling technique". That results were correspond with the change of the stomatal aperture width. That is to say, stomatal movement of Agave is due to the change of K+and Na+ concentration in the guard cells. As Agave which was used in this experiment showed two peaks of which one was at 3 hour and the other was at 24 hour in stomatal aperture width, it was seemed that Agave had both characteristics of CAM and $C_3$pattern.