• Title/Summary/Keyword: leaf osmotic pressure

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Comparative Water Relations of Two Vitis vinifera Cultivars, Riesling and Chardonnay

  • Park, Yong-Mok
    • The Korean Journal of Ecology
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    • v.24 no.4
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    • pp.223-226
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    • 2001
  • The leaf water relations and photosynthetic rate during acute soil drying were compared in potgrown grapevine cultivars, Vitis vinifera cv. Chardonnay and V. vinifera cv. Riesling. Leaf water potential in Riesling decreased significantly from day 2 after water had been withheld, while in Chardonnay leaf water potential for the water-stressed plants was almost identical with that in well watered plants during the first 4 days. Higher stomatal conductance and photosynthetic rate in Chardonnay than Riesling were observed until day 3 after withholding water. Photosynthetic rate in water-stressed Chardonnay was not different from that in control plants until day 3 after withholding water, while that in water-stressed Riesling was reduced markedly from day 2. In Riesling, osmotic potential at turgor loss point was not changed irrespective of watering conditions. However, in Chardonnay osmotic potential at turgor loss point decreased more in the water stressed conditions than in well watered conditions. The osmotic adjustment in Chardonnay under water stress conditions must contribute to the maintenance of higher stomatal conductance and photosynthetic rate than those in Riesling for a significant period of the drying process. Though difference in stomatal conductance between the two cultivars was shown in the process of soil drying, stomatal conductance of both cultivars responded to vapor pressure difference between leaf and ambient air, rather than soil water status and leaf water potential.

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The Characteristics of Diurnal Changes in the Tissue-Water Relations of Pueraria thunbergiana (칡(Pueraria thunbergiana) 조직수분관계의 일변화 특성)

  • 박용목;최창렬
    • The Korean Journal of Ecology
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    • v.21 no.1
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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.

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Responses of Transgenic Tobacco Plants Overexpressing Superoxide Dismutase and Ascorbate Peroxidase in Chloroplasts to Water Stress (Superoxide Dismutase와 Ascorbate Peroxidase를 엽록체에 과발현하는 형질전환 담배의 수분스트레스에 대한 반응)

  • 최선미;권석윤;곽상수;박용목
    • Journal of Environmental Science International
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    • v.10 no.1
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    • pp.79-84
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    • 2001
  • To assess resistance of transgenic tobacco plants which overexpress superoxide dismutase (SOD) and ascorbate peroxidase (APX) in chloroplasts to water stress, changes in leaf water potential, turgor potential, stomatal conductance and transpiration rate were measured. Leaf water potential in all plants remained high up to day 4 after withholding water but thereafter decreased markedly. In spite of a remarkable decrease in leaf water potential, some of transgenic plants maintained higher turgor potential compared with control plant on day 12. In particular, the transgenic plant expressing MnSOD showed an outstanding maintenance in turgor pressure by osmotic adjustment throughout the experiment, resulting in high stomatal conductance and transpiration rate. However, among transgenic plants, osmotic potential was reduced more effectively in multiple transformants such as the double transformant expressing both MnSOD and APX, and the triple transformant expressing CuznSOD, MnSOD and APX than single transformants. Consequently, further research is needed to get general agreement on the tolerance of transgenic plants to water stress at different growth stages for each transgenic plant.

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Evaluation of Drought Tolerance of Oplopanax elatus Obtained from Pressure-Volume Curves (P-V 곡선법을 활용한 땃두릅나무의 내건성 평가)

  • Lee, K.C.;Kwon, Y.H.;Kwon, Y.K.;Han, S.K.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.21 no.1
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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.

Changes in Physiological Characteristics of Barley Genotypes under Drought Stress (한발저항성 정도가 다른 보리 품종들의 한발처리에 따른 생리적 특성변화)

  • 이변우;부금동;백남천;김정곤
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.48 no.6
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    • pp.506-515
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    • 2003
  • Six barley varieties that showed different degree of drought tolerance were grown with and without drought stress treatment (control), and investigated for the temporal changes in growth and several physiological traits after drought treatment. Soil water potential was -0.05 ㎫ at the initial stage of drought treatment and dropped to -0.29 ㎫ at 19 days after withholding irrigation. Soil water potential (SWP) maintained at -0.05 ㎫ in the control. The dry weight (DW) under the drought treatment were reduced compared to the control as follows: Dicktoo-S (short awn), 69% ; Dicktoo-L (long awn), 70%; Dicktoo-T (tetra), 86%; Dongbori-1, 69%; Suwonssalbori-365, 55% and Tapgolbori, ,37%. Dicktoo lines and Dongbori-1 were more tolerant than Suwonssalbori-365 and Tapgolbori. Leaf relative water contents (RWC) and leaf water potential (LWP) decreased obviously under the drought condition, the decrease being greater especially in the less drought-tolerant barley genotypes. Dongbori-1 and Dicktoo-L in drought treatment showed net photosynthesis of 38% and 17% compared to the control, respectively, and the other four genotypes much lower photosynthesis of 1.1% to 7.0%. Stomatal conductance, mesophyll conductance, and the photochemical efficiency (Fv/Fm) of PS II were reduced by drought treatment, the reduction being greater in drought-sensitive genotypes. The drought-tolerant genotypes had greater osmotic adjustment (OA) capacity under water stress. Thus, the decrease of RWC and LWP was lower and the turgor pressure conservation capacity was higher under water stress in drought-tolerant genotypes. Drought-tolerant genotypes showed less decrease of photosynthesis because stomatal conductance, mesophyll conductance and the ratio (Fv/Fm) of the variable to maximal fluorescence of drought-resistant genotype was decreased less in the drought stress condition. In conclusion, the drought-tolerant genotypes had better water conservation capacity through efficient OA, and this led to the lower decrease of photosynthesis and growth in water stress condition.

Effect of Water States of Fruit Vesicle and Leaf on Fruit Quality in 'Trifoliate' Orange and 'Swingle citrumelo' Rootstock of 'Shiranuhi' [(Citrus unshiu ${\times}$ C. sinensis) ${\times}$ C. reticulata] Mandarin Hybrid, M16 A Line in Plastic Film House Cultivation (시설재배 '부지화' M16 A계통의 '탱자'와 '스윙글 시트루멜로' 대목과 과실 및 잎의 수분상태가 과실품질 차이에 미치는 영향)

  • Han, Sang-Heon;Kang, Jong-Hoon
    • Journal of Bio-Environment Control
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    • v.20 no.3
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    • pp.204-210
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    • 2011
  • This experiment was conducted to investigate the effect of water states (water, osmotic potential and turgor pressure) of fruit vesicle and leaf on soluble solids and organic acid contents of fruits of 'Shiranuhi' mandarin hybrid, M16 A line during the fruit maturing season in plastic house cultivation. The 'Shirauhi' grafted on 'Swingle citrumelo', strong strength of rootstock, produced fruit with lower soluble solids and organic acid content than 'Trifoliate' orange rootstock. The fruits vesicle water potential and turgor pressure measured before dawn in 'Swingle citrumelo' were higher tendency than the 'Trifoliate' orange, but osmotic potential values were lower than the 'Trifoliate' orange. The changes of leaf water potential were very similar to the fruit. The results suggest that in the 'Shirauhi' fruits grafted on two rootstocks changes of soluble solids and organic acid content of the fruit were influenced by the leaf water potential and the osmotic potential of the fruit vesicles, which might be caused by the difference of root distribution between two rootstocks.

Effects of Light, Temperature, Water Changes on Physiological Responses of Kalopanax pictus Leaves(IV) - Characteristics of Leaf Water Relations Obtained from P-V Curve - (광, 온도, 수분 변화에 따른 음나무 엽의 생리반응(IV) - P-V 곡선에 의한 잎의 수분특성 -)

  • Han, Sang-Sup;Jeon, Doo-Sik;Sim, Joo-Suk;Jeon, Seong-Ryeol
    • Journal of Forest and Environmental Science
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    • v.22 no.1
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    • pp.71-75
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    • 2006
  • Water relations of Kalopanax pictus leaves obtained from the P-V curve. In the upper leaves of Kalopanax pictus seedlings, the original osmotic pressure at maximum turgor was -1.44 MPa, and the osmotic pressure at incipient plasmolysis point was -1.84 MPa, and the relative water content at incipient plasmolysis point was 78.2%.

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Comparison of Adjustments to Drought Stress Among Seedlings of Several Oak Species

  • Kim, Joon-Ho
    • Journal of Plant Biology
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    • v.37 no.3
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    • pp.343-347
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    • 1994
  • In order to compare the adjustment of 6 oak species to water stress, the components of water status, tissue elastic modulus, free proline content of leaves and morphological characteristics were determined in pot culture. uercus dentata and . mongolica responded effectively to drought with high root : shoot (R/S) ratio or maintenance of high turgor pressure by large and fast osmotic adjustment and . variabilis with maintenance of high turgor pressure by low elastic modulus under drought. Meanwhile, . aliena and . serrata responded effectively with low omotic potential (Ψo) at full saturation and . acutissima with long root in spite of rigid cell wall and high osmotic potential (Ψo) at full saturation. Proline content in leaves of . dentata, . mongolica and . aliena increased early and rapidly at high leaf water potential (Ψleaf). The results indicate that 6 oak species have adjustment different from each other to water stress.

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Water Relations Parameters of Heracleum moellendorffii Hance Obtained from Pressure-Volume Curves (P-V 곡선법을 활용한 어수리의 수분특성 분석)

  • Lee, K.C.;Kwon, Y.H.;Lee, K.M.;Han, S.K.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.19 no.1
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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 (Ψosat) was -1.0MPa, and that at incipient plasmolysis (Ψotlp) -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 RWCtlp and RWC* were above 88%, showing that the function of osmoregulation is somewhat better. Thus, responses to water relations such as Ψosat, Ψotlp, Emax, RWCtlp and RWC* of H. moellendorffii showed it's slightly high drought tolerance property.

Ecophysiological Interpretations on the Water Relations Parameters of Trees(V) -Seasonal Changes in Tissue-Water Relations on the Quercus grosseserrata and Quercus acutissima Leaves- (수목(樹木)의 수분특성(水分特性)에 관한 생리(生理)·생태학적(生態學的) 해석(解析)(V) -물참나무와 상수리나무 엽(葉)의 수분특성(水分特性)의 계절변화(季節變化)-)

  • Han, Sang Sup;Choi, Heung Seon
    • Journal of Korean Society of Forest Science
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    • v.72 no.1
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    • pp.37-44
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    • 1986
  • Seasonal changes of water relations parameters were obtained from p-v curves in leaves of Quercus grosseserrata and Quercus acutissima. The osmotic pressure at full hydration, ${\pi}_o$, and osmotic pressure at incipient plasmolysis, ${\pi}_p$, were high in newly emerged leaves but decreased with leaf development in each of the species. Water deficit at turgor loss was 10 to 20% in each of the species during the growing season. Maximum bulk elastic modulus in cell walls at full turgor, Emax, rises rapidly with leaf development before senescence in each of the species. Seasonal change of number of osmoles solute in symplasm per dry weight, Ns/DW, was higher in Quercus grosseserrata leaves than Quercus acutissima leaves, while relative water content (Vp/Vo, $RWC^*$, Vo/Vt) was relatively constant in each of the species.

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