• Journal of Ginseng Research
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• v.17 no.3
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• pp.240-245
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• 1993

This study was conducted with ginseng plants to investigate photosynthetic response to changes of light intensity and leaf temperature. $CO_2$ uptake in diurnal course was highest in the first phase (8 00~5 : 30 Am.) on May 30, 1992. In $CO_2$ uptake related to stomatal conductance, these relationship was synchronized in diurnal course, but relationship between TEX>$CO_2$ uptake and intercellular $CO_2$ concentration in diurnal course was synchronized oppositely. Leaf temperature and light intensity at the highest $CO_2$ uptake were in the range of 23~$24^{\circ}C$) and 95$\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ , respectively. In response to an increasing light intensity under a constant leaf temperature ($18^{\circ}C$), $CO_2$ uptake was increased throughout the light intensity sequence up to 250$\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ When $CO_2$ uptake was measured with a series of leaf temperature under a constant light intensity (250 $\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ uptake was highest at $18^{\circ}C$ as a 4.1$\mu$mol.$m^{-2}$.$s^{-1}$), $CO_2$ . Similar changes were also observed in stomatal conductance and intercellular $CO_2$ concentration. Evidences from several approaches indicate that synchronization of $CO_2$ uptake, stomatal conductance and intercellular $CO_2$ concentration were closely inter-related and changes of leaf temperature iuluenced the photo-response in photosynthetic processes.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.151-157
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• 2017

The objectives of this study were to determine the impact of soil water content on the growth, stomatal conductance, and photosynthesis of Kimchi cabbage and to evaluate proper parameters for development of growth models. There were five levels of irrigation amount treatments (0, 200, 300, 400, and 500 mL/d/plant) and those were commenced at one day after transplanting (DAT). We measured soil water content, stomatal conductance, photosynthesis characteristics, and the A-Ci curve. The growth of Kimchi cabbage as affected by irrigation amount was evaluated at 38 days after transplanting, however, the growth with 0 and 200 mL/d/plant irrigation amount treatments measured at 29 DAT. The relationship between soil water content and stomatal conductance was highly correlated ($r^2=0.999$) and the function represented by y = 6097.4x - 4.2984. The stomatal conductance of Kimchi cabbage leaves showed $300mmol{\cdot}m^{-2}{\cdot}s^{-1}$ when the soil water content was below $0.05m^3/m^3$. The stomatal conductance was rapidly decreased by scarcity of soil moisture. A-Ci curve indicated normal curve in fully irrigation treatment (500 mL/d/plant), however, $CO_2$ couldn't diffuse through the intercellular Kimchi cabbage leaves treated with 0 mL/d/plant. The dry weight of full irrigation treatment was greater approximately 6.8 times than that of deficit irrigation (0 mL/d/plant). In addition, leaf area index showed a logarithmic function (y = 16.573 + 3.398 ln x) with soil water content and that of R-squared represents 0.913. Results indicated that the soil water content was highly correlated with stomatal conductance and leaf area index. Indeed, the scarcity soil moisture reduced photosynthesis and retarded growth.

• Korean Journal of Environmental Biology
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• v.18 no.2
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• pp.263-268
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• 2000

The effect of $Cd^{2+}$ on stomatal apertures of epidermal strips and intact leaves in Commelina communis L. was investigated. Cadmium stimulated stomatal opening. The stomata, treated with 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 ${\mu}{\textrm}{m}$. In order to show that there was no mechanical or osmotic impediment preventing the stomata in the epidermal strips, salicylic acid (SA) and abscisic acid (ABA) were used. The treatment of 100 $\mu$M SA and 1 $\mu$M ABA inhibited 14% and 28% of stomatal opening, respectively. Other heavy metals such as $Al^{3+} and Ag^{2+}$ were also used to investigate the effect of the stomatal apertures. The treatment of $Al^{3+} and Ag^{2+}$ also stimulated 19% and 41% of stomatal opening. To understand how cadmium open stomata, the effect of cadmium on the K+ influx into the epidermal strips was investigated. $Cd^{2+}$, SA, ABA inhibited 98%, 28%, 34% of K+ uptake respectively. 3-weeks old Commelina was transferred to and grown in Hoagland solution (0,5 mM $Cd^{2+}$, 10 mM $Cd^{2+}$) for 4 days and stomatal conductance were measured. The treatment of 5 mM $Cd^{2+}$ and 10 mM $Cd^{2+}$ showed about 51% and 70% inhibition of stomatal conductance, respectively Therefore, it could be concluded that stomata in epidermal strips and intact leaves behaved differently and cadmium- stimulated stomatal opening was due to the result of cadmium uptake into the epidermal strips instead of K+. [cadmium, stomata, stomatal conductance]

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.453-463
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• 1996

Diurnal changes of microclimatic conditions and tissue water relations were measured at two sites where Carpinus laxiflora and C. cordata were allopatrically distributed. The microclimatic conditions at a site where C. laxiflora was distributed produced severe water stress condition during summer months. Daily maximum temperature reached $30.4^\circC$ and the highest vapor pressure deficit was 1.31 KPa when 13 rainless days were continued. During this period soil water content decreased to below the field capacity even at a depth of 20 cm and xylem pressure potential also decreased to ­2.04 MPa. However, turgor potential was maintained more than 0.4 MPa. Patterns of stomatal conductance were changed with evaporative demand and soil water availability. On the other hand, microclimatic conditions at a site where C. cordata was distributed were moderate water strees condition compared with those at a site C. laxiflora was distributed. Though soil water content was maintained above field capacity C. cordata showed a remarkable decrease in turgor potential and stomatal conductance throughout the experiment. These results indicate that there is a difference in habitat characteristics between the two species and C. laxiflora is more resistant than C. cordata to water stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.303-309
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• 2006

The study examined the effects of $CO_2$ enrichment on growth of soybean (Glycine max). Two soybean varieties were used, Taekwang and Cheongja. The plants were grown in growth chambers with a 12-h photoperiod and a day/night temperature of $28/21^{\circ}C$ at the seedling stage and $30/23^{\circ}C$ from the flowering stage. The plants were exposed to the two elevated $CO_2$ levels of 500 and 700 ppm and the ambient level of 350 ppm. Results of the experiment showed that at the second-node trifoliate stage of the two varieties, the elevated $CO_2$ increased plant height, leaf area and dry weight. The elevated $CO_2$ also raised the photosynthetic rate of soybean as compared to the ambient level. From the beginning bloom stage to the full maturity stage of the two varieties, the elevated $CO_2$ increased plant height, leaf area, seed weight and photosynthetic rate. The stomatal conductance and transpiration rate decreased on long days relative to short days of treatment. Through the entire stages, the elevated $CO_2$ increased the water use efficiency of soybean plants because stomatal conductance and transpiration rate decreased at the elevated $CO_2$ levels relative to the ambient level.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.3
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• pp.263-268
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• 1996

This study was conducted for the assessment of the effects of acid rain and soil fertilizers on photosynthetic rate, was content, and contact angle on 5-year seedlings of Japanese red pine (Pinus densiflora Sieb. et Zucc.) leaves. The seedlings were exposed to pH 3.0 (simulated acid rain), pH 6.5 (groung water) and rain (pH around 4.6). The seedlings were also treated with $Ca(OH)_2, Mg(OH)_2, and Ca(OH)_2 + Mg(OH)_2 + C.F.(compound fertilizer)$. Photosynthetic rate, stomatal conductance, was content, contact angle value, and mineral nutrient content of the leaves were measured and the results were as follows: 1. Photosynthetic rate and stomatal conductance of the leaves increased with the increase of pH. Photosynthetic rate and stomatal conductance increased with application of soil fertilizer in the pH 3.0 treatment, but showed no changes in the rain and the pH 6.5. 2. Contact angle value and was content of the leaves did not change with the pH treatment, but increased with the fertilizer treatments. 3. Mineral nutrient contents of the leaves were lowest in the rain treatment and highest in the pH 6.5 treatment. The increase of mineral nutrient contents was observed with the soil fertilizer treatments.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.416-420
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• 2008

This study was conducted to investigate the influence of shading material on the chlorophyll fluorescence, photosynthesis, transpiration, stomatal conductance and its any correlations in Panax ginseng C.A.Meyer. Fo was higher in polyethylene shade net than in silver-coated shading plate, but this treatment caused a lower Fm in comparison with silver-coated shading plate. Also, Fv/Fm and PhiPS2 showed higher in silver-coated shading plate than in polyethylene shade net. The relationship between net photosynthetic rate and transpiration, stomatal conductance were increased as the PAR (Photosynthetic active radiation) was increased and reached maximum at the $200-400\;{\mu}mol/m^{2}/s$ of PAR in all of leaves, and the higher in silver-coated shading plate than in polyethylene shade net. A linear equation was obtained between net photosynthetic rate and transpiration, net photosynthetic rate and stomatal conductance. SPAD was higher in silver-coated shading plate than in polyethylene shade net.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.168-172
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• 1996

The soil moisture content and its relation to plants may be important in determining the crop growth and yield. The present study was undertaken to evaluate the leaf water potential and photosynthetic activity in soybean plants as affected by the timing of soil water stress. The soybean variety, 'Tachinagaha', was grown in a pot. The 15 day-old seedlings were subject to the three levels of soil moisture content(25, 40 and 55%) for 25 days. Then the treated soybean plants were placed again at the level of 25% soil moisture content for 25 days, and were compared with the control which was well-watered at 40% level for whole growth period. Soybean plants grown under continuous drought showed higher apparent photosynthetic rate(AP) than those under well-watering /drought in the first /second water treatment, suggesting that AP was adjusted after previous acclimation to drought. Over a wide range of photosynthetic photon flux densities(PPFD), drought or excessive water stress resulted in the decrease in AP when compared with the control. AP and stomatal conductance were decreased in soybean plants subject to water deficit stress, suggesting that AP and stomatal conductance were more sensitive to drought than excessive water stress.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.335-335
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• 2017

Recently NERICA (New Rice for Africa) was developed by a crossing of African rice (Oryza glaberrima Steud.) and Asian rice (Oryza sativa L.) in West Africa, and is considered to be drought resistant, but drought resistance of NERICA and differences between Asian rice are not clarified enough. In this research, NERICA (four cultivars and two lines), Asian rice (three cultivars and sativa parent of NERICA) and African rice (glaberrima parent of NERICA) were cultivated in the field in Shizuoka University under drought and traits of each cultivar and line relevant to drought resistance, stomatal conductance by porometer, soil water content of individual depths by TDR method, SPAD values by SPAD meter and leaf thickness by micrometer, were measured and compared with dry matter production and yield. Effects of compost were also compared among sativa parent, one NERICA cultivar and two NERICA lines. Glaberrima parent showed highest top dry weight. One NERICA line, one drought resistant Asian rice cultivar and sativa parent, showed higher top dry weight and yield (ear weight) than other Asian rice cultivars and NERICA cultivars and line tested. Compost tended to increase top dry weight and yield in one of NERICA line and sativa parent. But in one NERICA cultivar and line, top dry weight and yield were not increased. In one of Asian rice, one of NERICA line and sativa parent that showed high top dry weight and yield, stomatal conductance was high. On the contrary the glaberrima parent and in other NERICA cultivars and line it was low. In sativa parent compost increased stomatal conductance but in NERICA cultivar and lines it was not. Among cultivars and lines that showed high top dry weight and yield sativa parent and one of NERICA line SPAD value and leaf thickness were high but in one of Asian rice and glaberrima parent they were low. Cultivar and line differences in yield and top dry weight among Asian rice and NERICA were significantly correlated with those in stomatal conductance ($r=0.778^{**}$ and $r=0.654^*$, respectively) and those in leaf thickness ($r=0.600^*$ and $r=0.640^*$, respectively). In Asian rice cultivars average soil water content was significantly correlated with yield ($r=0.886^*$) but in NERICA cultivars and lines it was not significant correlated (r= -0.256). Cultivar and line differences in leaf thickness were significantly correlated with SPAD value ($r=0.773^{**}$). In Asian rice cultivars it was significantly correlated ($r=0.962^{**}$), but in NERICA cultivars and lines it was not significantly correlated (r=0.559). Asian rice cultivars tended to consume soil water to increase yield but in NERICA cultivars and lines the tendency was not clear. Correlation between SPAD value and leaf thickness was different between Asian rice and NERICA cultivars and lines, and in Asian rice cultivars it was significantly correlated but in NERICA cultivars and lines it was not significant. Importance of maintaining high stomatal conductance by high leaf thickness was clarified.

• 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.