• The Korean Journal of Ecology
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• 제19권5호
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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.

• 한국약용작물학회지
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• 제26권2호
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• pp.181-187
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• 2018

Background: This study aimed to investigate out the influence of drought stress on the physiological responses of Dendropanax morbifera seedlings. Methods and Results: Drought stress was induced by discontinuing water supply for 30 days. Under drought stress, photosynthetic activity was significantly reduced with decreasing soil water content (SWC), as revealed by the parameters such as Fv/Fm, maximum photosynthetic rate ($P_{N\;max}$), stomatal conductance ($g_s$), stomatal transpiration rate (E), and intercellular $CO_2$ concentration (Ci). However, water use efficiency (WUE) was increased by 2.5 times because of the decrease in $g_s$ to reduce transpiration. Particularly, E and $g_s$ were remarkably decreased when water was withheld for 21 days at 6.2% of SWC. Dendropanax morbifera leaves showed osmotic adjustment of -0.30 MPa at full turgor and -0.13 MPa at zero turgor. In contrast, the maximum bulk modulus of elasticity ($E_{max}$) did not change significantly. Thus, Dendropanax morbifera seedlings could tolerate drought stress via osmotic adjustment. Conclusions: Drought avoidance mechanisms of D. morbifera involve reduction in water loss from plants, through the control of stomatal transpiration, and reduction in cellular osmotic potential. Notably photosynthetic activity was remarkably reduced, to approximately 6% of the SWC.

• 한국작물학회지
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• 제44권1호
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• pp.55-58
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• 1999

Plant water status during growth is directly and indirectly associated with seed yield. The objective of the present study was to determine the genotypic differences in leaf water characteristics at an early growth stage of soybean [Glycine max (L.) Merrill] plants through the pressure-bomb technique. Measurements of water potential as well as relative water content (RWC) were made at the third leaf from the fully-expanded top leaf of eight different soybean genotypes grown for 31 to 35 days after field emergence. On the basis of the modified exponential model, pressure-volume (PV) curves were fitted well ($R^2$=0.92＊＊ to 0.99＊＊ for the curvi-linear region and R=0.67＊＊ to 0.96＊＊ for the linear region), indicating that a segmented model using PROC NLIN of SAS could be used effectively to estimate the leaf water characteristics. The regression analysis for the pressure-volume (PV) curve revealed genotypic variation in the solute potential at saturation (Ψ$_{s,sat}$ :-10.7 to -14.8 bar), solute potential at incipient plasmolysis (Ψ$_{s,ip}$ : -14.3 to -18.3 bar), RWC at incipient plasmolysis (RW $C_{ip}$ : 83.3 to 91.7%), high integrated turgor pressure from saturation to plasmolysis ( $_1$$^{b}$ : 0.39 to 0.81), and maximum volumetric modulus of elasticity ($\varepsilon$$_{max}$ : 150 to 445 bar).).

• 한국산림과학회지
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• 제72권1호
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• pp.37-44
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• 1986

물참나무엽(葉)과 상수리나무엽(葉)의 수분특성인자(水分特性因子)의 계절변화(季節變化)를 p-v곡선법(曲線法)에 의해 측정(測定)하였다. 양수종(兩樹種)의 최대포수시(最大飽水時)의 침투압(浸透壓) ${\pi}_o$와 초기원형질(初期原形質) 분이점(分離點)의 침투압(浸透壓) ${\pi}_p$는 생육초기(生育初期)에 높고 성숙엽(成熟葉)이 되어 가면서 감소(減少)하였다. 전생육기간(全生育期間)을 통해 양수종(兩樹種)은 전수분량(全水分量)의 약(約) 10~20%의 수분(水分)을 상실(喪失)할 때 팽압(膨壓)이 0에 달(達)했다. 양수종(兩樹種)의 최대포수시(最大飽水時)의 유포(釉胞)의 탄성계수(彈性係數), Emax는 엽(葉)이 신장(伸長)함에 따라 증가(增加)하였으며, 경엽화(硬葉化)된 이후(以後)는 감소(減少)하였다. 오스몰수, Ns/DW의 위절변화(委節變化)는 물참나무엽(葉)이 상수리나무엽(葉)보다 컸으며, 상대함수율(相對含水率)(Vp/Vo, $RWC^*$, Vo/Vt)은 비교적 위절변화(委節變化)가 작았다.

• Journal of Forest and Environmental Science
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• 제22권1호
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• pp.71-75
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• 2006

P-V곡선에 의한 음나무 묘목 상층엽의 수분특성을 측정하였다. 음나무 잎의 최대팽압시의 삼투포텐셜은 -1.44 MPa 이었고, 초기원형질분리점의 삼투포텐셜은 -1.84 MPa, 초기원형질분리점의 상대함수율은 78.2%였다.

• 한국자원식물학회지
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• 제24권4호
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• pp.413-418
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• 2011

P-V 곡선을 적용하여 참취와 수리취의 수분특성인자를 측정한 결과 최대포수시의 삼투포텐셜 ${\Psi}^{sat}_o$과 초기원형질 분리점의 삼투포텐셜 ${\Psi}^{tlp}_o$은 참취가 수리취보다 낮은 값을 나타냈으나 큰 차이를 보이지는 않았다. 최대팽압 ${\Psi}_{P,max}$는 참취가 수리취에 비해 높게 나타났으며, 최대탄성계수 $E_{max}$는 참취가 수리취에 비해 약 2.4배 정도 높은 값을 나타냈다. 초기원형질분리점에서의 상대함수율 $RWC^{tlp}$은 참취와 수리취 모두 90% 이상의 함수율을 보여 비교적 삼투 조절기능이 좋은 것을 알 수 있었고, apoplastic water의 비율은 참취가 더 크며, Vo/DW, Vt/DW, Ns/DW은 수리취가 참취에 비해 약 1.5~2.0배 정도 큰 경향을 보였다. 위 결과를 통해 참취와 수리취 모두 초기원형질분리점과 최대포수시의 삼투포텐셜이 높은 편으로 내건성은 비교적 약한 것으로 나타났으며, 습윤한 지역이 생육에 적합함을 알 수 있었다. 또한, 참취와 수리취를 비교할 때 참취가 수리취에 비해 건성잎의 특성을 가지고 있으며, 최대탄성계수와 삼투포텐셜이 높아 내건성이 약간 더 강한 것을 알 수 있었다.

• The Korean Journal of Ecology
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• 제21권1호
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• pp.89-96
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• 1998

The diurnal changes of the stomatal conductance, transpiration and leaf water potential were measured in order to assess the water relations characteristics of Pueraria thunbergiana in August of 1995 and 1996. The results showed two different responses depending on the duration of rainless days. The microclimatic conditions were highly stressful on 2 August. Daily maximum temperature reached to $39.0{\circ}C$ and vapor pressure deficit was 3.55 KPa. During this time the leaf water potential decreased to -1.02 MPa and a marked reduction of stomatal conductance was shown. However, on 15 August the stomatal conductance increased with increment of photon flux density, and transpiration was highly maintained during the day time. Minimum leaf water potential was only -0.47 MPa in spite of high transpiration rate. Furthermore, on 15 August reduced leaf water potential during the day time was recovered rapidly with decrease of photon flux density, whereas recovery of leaf water potential on 2 August was delayed. However, reduced leaf water potential on 2 August was recovered untile the next dawn. Osmotic potential at turgor loss point of Pueraria thunbergiana on 2, 3 and 15 August was -1.79, -1.70 and -1.60 MPa, respectively. The vapor pressure deficit is more contributive to the regulation of stomatal conductance than leaf water potential.

• 한국약용작물학회지
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• 제20권1호
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• pp.36-41
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• 2012

This study was carried out to establish a proper cultivation site and diagnose the drought tolerance of Pleurospermum camtschaticum, Cirsium setidens and Parasenecio firmus leaves by using pressure-volume curves. The result of ${\Psi}_o^{sat}$ and ${\Psi}_o^{tlp}$ were lower in Pleurospermum camtschaticum leaves. On the other hand, it appeared that $E_{max}$ of Pleurospermum camtschaticum was approximately six times higher than that of Parasenecio firmus. The values of $RWC^{tlp}$ is all above 88% showing that the function of osmoregulation is somewhat better, and Vo/DW, Vt/DW, Ns/DW of Pleurospermum camtschaticum leaves were approximately 2~4 times Lower than other ones. Thus, responses to water relations of Pleurospermum camtschaticum, Cirsium setidens and Parasenecio firmus such as ${\Psi}_o^{sat}$, ${\Psi}_o^{tlp}$, $E_{max}$, ${\Psi}_{P,max}$, $RWC^{tlp}$ were shown that the Pleurospermum camtschaticum leave was higher drought tolerance than Cirsium setidens and Parasenecio firmus leaves.

• 현장농수산연구지
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• 제19권1호
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• pp.91-97
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• 2017

This study was carried out to establish a proper cultivation site and to diagnose the drought tolerance of Heracleum moellendorffii leaves by using pressure-volume curves. As a result of analysing data measured, the leaf of H. moellendorffii showed the osmotic pressure at full turgor (Ψ_o^sat) was -1.0MPa, and that at incipient plasmolysis (Ψ_o^tlp) -1.2MPa. Then, the value of maximum bulk modulus of elasticity Emax was 28MPa, showing the sightly strong drought tolerance of H. moellendorffii. Furthermore, the values of relative water contents RWC^tlp and RWC^* were above 88%, showing that the function of osmoregulation is somewhat better. Thus, responses to water relations such as Ψ_o^sat, Ψ_o^tlp, E_max, RWC^tlp and RWC^* of H. moellendorffii showed it's slightly high drought tolerance property.

• 현장농수산연구지
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• 제21권1호
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• pp.41-48
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• 2019

This study was carried out to establish a proper cultivation site and to diagnose the drought tolerance of Oplopanax elatus leaves by using pressure-volume curves. As a result of analysing data measured, the leaf of Oplopanax elatus showed the osmotic pressure at full turgor(Ψosat) was -0.77 MPa, and the osmotic pressure at incipient plasmolysis(Ψotlp) was -0.90 MPa. Then, the value of maximum bulk modulus of elasticity Emax was 3.7 MPa, showing that slightly lower drought tolerance of Oplopanax elatus. Furthermore, the values of relative water contents RWCtlp and RWC^* were above 80%, showing that the function of osmoregulation is somewhat better. Thus, responses to water relations such as Ψosat, Ψotlp, Emax, RWCtlp and RWC^* of Oplopanax elatus showed relatively lower drought-tolerance property indicating that those growth are appropriate in high moisture soil sites.