scholarly journals The Components of Leaf Water Potential II. Pressure Potential and Water Potential

1967 ◽  
Vol 20 (2) ◽  
pp. 349 ◽  
Author(s):  
J Warren Wilson
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Leaf Water ◽  
Pressure Potential ◽  
First Approximation ◽  
Relative Water

The relation between the relative water content (R) and the pressure potential can be expressed through the coefficient of enlargement (e). The assumption that e does not vary with R is for many leaves a useful first approximation even when R is so low that pressure potential is negative. e is estimated at between 7 and 84 bars for various leaf types.

scholarly journals Relationships Among Water Potential Components, Relative Water Content, and Stomatal Resistance of Field-Grown Peanut Leaves1

1984 ◽  
Vol 11 (1) ◽  
pp. 31-35 ◽  
Author(s):  
J. M. Bennett ◽  
K. J. Boote ◽  
L. C. Hammond
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Leaf Water ◽  
Peanut Crop ◽  
Relative Water ◽  
Volumetric Soil Water

Abstract Limited data exist describing the physiological responses of peanut (Arachis hypogaea L.) plants to tissue water deficits. Detailed field experiments which accurately define the water status of both the plant and soil are required to better understand the effects of water stress on a peanut crop. The objectives of the present study were 1) to describe the changes in leaf water potential components during a drying cycle, and 2) to define the relationships among soil water content, leaf water potential, leaf turgor potential, relative water content, leaf-air temperature differential, and leaf diffusive resistance as water stress was imposed on a peanut crop. During a 28-day drying period where both rainfall and irrigation were withheld from peanut plants, midday measurements of the physiological parameters and volumetric soil water contents were taken concurrently. As soil drying progressed, water extraction from the upper soil depths was limited as soil moisture approached 0.04 m3m-3. Leaf water potentials and leaf turgor potentials of nonirrigated plants decreased to approximately −2.0 and 0 MPa, respectively, by the end of the experimental period. Leaf water potentials declined only gradually as the average volumetric soil water content in the upper 90 cm of soil decreased from 0.12 to 0.04 m3m-3. Further reductions in soil water content caused large reductions in leaf water potential. As volumetric soil moisture content decreased slightly below 0.04 m3m-3 in the upper 90 cm, leaf relative water content dropped to 86%, leaf water potential approached −1.6 MPa and leaf turgor potential decreased to 0 MPa. Concurrently, stomatal closure resulted and leaf temperature increased above air temperature. Osmotic potentials measured at 100% relative water content were similar for irrigated and nonirrigated plants, suggesting little or no osmotic regulation.

scholarly journals Comparison of Strawberry F. chilocnsis and F. ×ananassa in Response to Water Stress: I. Leaf Water Potential, Relative Water Content, and Gas Exchange Characteristics

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 601c-601
Author(s):  
Chuhe Chen ◽  
J. Scott Cameron ◽  
Stephen F. Klauer
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Leaf Water ◽  
Severe Water Stress ◽  
Relative Water ◽  
Gas Exchange Characteristics

Leaf water potential (LWP), relative water content (RWC), gas exchange characteristics, and specific leaf weight (SLW) were measured six hours before, during, and after water stress treatment in F. chiloensis and F. ×ananassa grown in growth chambers. The leaves of both species showed significantly lower LWP and RWC as water stress developed. F. ×ananassa had consistency lower LWP under stressed and nonstressed conditions than F. chiloensis. F. ×ananassa had higher RWC under nonstressed conditions, and its RWC decreased more rapidly under water stress than F. chiloensis. In comparison to F. ×ananassa, F. chiloensis had significantly higher CO2 assimilation rate (A), leaf conductance (LC), and SLW, but not transpiration rate (Tr), under stressed and nonstressed conditions. LC was the most sensitive gas exchange characteristic to water stress and decreased first. Later, A and stomatal conductance were reduced under more severe water stress. A very high level of Tr was detected in F. ×ananassa under the most severe water stress and did not regain after stress recovery, suggesting a permanent damage to leaf. The Tr of F. chiloensis was affected less by water stress. Severe water stress resulted in higher SLW of both species.

scholarly journals Effect of drought stress on water relation traits of four soybean genotypes

2018 ◽  
Vol 15 (2) ◽  
pp. 163-175 ◽  
Author(s):  
JA Chowdhury ◽  
MA Karim ◽  
QA Khaliq ◽  
AU Ahmed ◽  
ATM MI Mondol
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Leaf Temperature ◽  
Leaf Water ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Relative Water ◽  
Exudation Rate

An experiment was conducted in a venyl house at the environmental stress site of Bangabandhu Sheikh Mujibur Rahman Agricultural University during September to December 2012 to know the internal water status under drought stress in soybean genotypes, viz. Shohag, BARI Soybean-6, BD2331 (relatively stress tolerant) and BGM2026 (susceptible). Drought (water) stress reduced the leaf water potential in all the genotypes though was more negative in tolerant genotypes than in susceptible ones. The lowest leaf water potential was obtained from BARI Soybean-6 (-1.58 MPa) and the highest in BGM2026 (-1.2 MPa). Relative water content (RWC) decreased remarkably in all the genotypes and reduction was more in susceptible than tolerant genotypes. At 8.00 am, RWC of stressed plants decreased by 9.58, 9.02, 8.90 and 13.90% in the genotype Shohag,, BARI Soybean-6, BD2331 and BGM2026 at vegetative stage, respectively. Drought stress decreased the exudation rate in all the genotypes of soybean and it was 24, 27, 22 and 12 mg h-1 in the genotype Shohag, BARI Soybean-6, BD2331 and BGM2026 at vegetative stage, respectively. Leaf temperatures in drought stressed plant were higher than in well-watered plants. Shohag, BARI Soybean-6, BD2331 and BGM2026 showed 4.7, 4.5 5.2 and 11.07% increase in leaf temperature due to water stress. At drought stressed treatment reduction in leaf water potential, relative water content, exudation rate and water retention capacity were noticed at the three growth stages in all the genotypes with a concurrent increase in leaf temperature. Genotypes BARI Soybean-6, Shohag and BD2331 showed considerably less reduction in relative water content, exudation rate and water retention capacity, high reduction in leaf water potential and less increase in leaf temperature during drought were considered as drought tolerant. However genotype BGM2026 showed considerably high reduction in relative water content, exudation rate and water retention capacity, low reduction in leaf water potential and high increase in leaf temperature was considered as drought susceptible.SAARC J. Agri., 15(2): 163-175 (2017)

scholarly journals Prediction of leaf water potential and relative water content using terahertz radiation spectroscopy

Plant Direct ◽  
2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Marvin Browne ◽  
Nezih Tolga Yardimci ◽  
Christine Scoffoni ◽  
Mona Jarrahi ◽  
Lawren Sack
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Terahertz Radiation ◽  
Relative Water Content ◽  
Leaf Water ◽  
Relative Water

scholarly journals Genetic Analysis of Yield and Physiological Traits in Sunflower (Helianthus annuus L.) under Irrigation and Drought Stress

2014 ◽  
Vol 6 (2) ◽  
pp. 207-213
Author(s):  
Azam POURMOHAMMAD ◽  
Mahmoud TOORCHI ◽  
Seyed S. ALAVIKIA ◽  
Mohammad R SHAKIBA
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Proline Content ◽  
Leaf Water ◽  
Additive Effects ◽  
Relative Water ◽  
Chlorophyll Index

Implementing appropriate breeding strategies for sunflower, alongside dependable information on heritability and gene effects upon yield and related traits under drought conditions, are all necessary. Thirty sunflower hybrids were produced by line × tester cross of six male-sterile and five restorer lines. Their hybrids were evaluated in three levels of irrigation, as follows: (1) non-stressed plots, irrigated at regular intervals (W1); (2) mild water stress (W2), irrigated from the beginning of the button stage (R4) to seed filling initiation (R6); (3) severe water stress (W3) started from the beginning of button stage (R4) to physiological maturity. Based on observations and specific methods for determination, canopy temperatures, chlorophyll index, relative water content and proline content, were studied by additive effects, under the different irrigation conditions. Canopy temperatures,chlorophyll index, relative water content, leaf water potential, proline content and yield were controlled by additive effects under mild stressed conditions. Under severe stress conditions however, canopy temperatures, leaf water potential and proline content were controlled by additive effects, while chlorophyll index and relative water content were controlled by both additive and dominant effects, as seed yield was mainly influenced by the dominant effects. The narrow sense heritability ranged from 47-97% for all traits, except for chlorophyll fluorescence. Yield correlated positively with chlorophyll index and relative water content, and negatively with canopy temperature and leaf water potential. Therefore, under drought stressed conditions in breeding programs, canopy temperatures, chlorophyll index and relative water content can be reliable criteria for the selection of tolerant genotypes with prospect to higher yields.

scholarly journals PARÂMETROS FISIOLÓGICOS DE CULTIVARES DE CEVADA SOB DÉFICITS HÍDRICOS

Irriga ◽  
2008 ◽  
Vol 13 (4) ◽  
pp. 438-448 ◽  
Author(s):  
Alexandre Barreto Almeida dos Santos ◽  
Antonio Evaldo Klar ◽  
Cleber Júnior Jadoski
Keyword(s):  
Water Vapor ◽  
Water Stress ◽  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Leaf Water ◽  
Barley Cultivars ◽  
Leaf Resistance ◽  
Relative Water

PARÂMETROS FISIOLÓGICOS DE CULTIVARES DE CEVADA SOB DÉFICITS HÍDRICOS  Alexandre Barreto Almeida dos Santos; Antonio Evaldo Klar; Cleber Junior JadoskiDepartamento de Engenharia Rural, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, SP, [email protected]   1 RESUMO O objetivo deste trabalho foi estudar parâmetros fisiológicos em seis cultivares de cevada (Borema, Lagoa, BRS – 180, BRS – 195, BRS – 225 e EMB – 128), por meio da imposição de ciclos de seca em diferentes estágios fenológicos da cultura. Os tratamentos utilizados foram: T1 - vasos irrigados constantemente até o final do ciclo da cultura; T2 - ciclo de seca iniciado aos 45 dias após a semeadura (DAS) e T3 - ciclo de seca iniciado aos 65 DAS. Avaliaram-se a resistência difusiva ao vapor de água (Rs), teor relativo de água (TRA) e potencial de água na folha (Ψf). Utilizou-se o delineamento em blocos casualizados: quatro blocos, seis cultivares de cevada e três tratamentos, totalizando setenta e duas unidades experimentais. O experimento foi conduzido durante os meses de agosto a novembro de 2005, em estufa plástica localizada na área experimental do Departamento de Engenharia Rural - Faculdade de Ciências Agronômicas de Botucatu – UNESP. Os dados analisados permitiram concluir que todas as cultivares de cevada apresentaram adaptação ao déficit hídrico, porém a cultivar EMB – 128 foi a que apresentou maior tendência à tolerância à seca e a BRS180 amenor.  Os resultados mostraram que apenas um ciclo de seca  pode aumentar a tolerância à seca. UNITERMOS: resistência difusiva ao vapor de água, teor relativo de água e potencial de água na folha.   SANTOS, A. B. A.; KLAR, A. E.; JADOSKI, C. J. PHYSIOLOGICAL PARAMETERS IN  BARLEY  CULTIVARS UNDER  WATER  STRESS  2 ABSTRACT                   The objective of this study was to evaluate some physiological parameters in six barley cultivars (Borema, Lagoa, BRS-180, BRS-195, EMB-128 e BRS-225), under water stress in different crop phenological phases. The treatments were as follows: T1 - pots constantly irrigated until harvest; T2: - water stress starting from 45 days after sowing (DAS) and T3 -  water stress  starting from 65 DAS. Leaf resistance to water vapor diffusion (Rs), relative water content (RWC), and leaf water potential (Ψl) were used to evaluate drought tolerance.  Pots were arranged in a randomized block design with four blocks, six barley cultivars, and three treatments, in a total of seventy two pots. The experiment was conducted from August to November2005 ina polyethylene greenhouse located at the experimental area of Rural Engineering Department – FCA,  UNESP – Botucatu - SP.  The results showed that all barley cultivars presented some adaptation to water stress, but EMB-128 was the most likely and BRS-180 the least likely to be drought tolerant. The results revealed that only one drought cycle may increase tolerance to drought. KEY WORDS: Leaf resistance to water vapor diffusion, relative water content, and leaf water potential.

scholarly journals Capillary Mats Modify Media Moisture Content during Mist Propagation of Chrysanthemum Cuttings

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 634a-634
Author(s):  
Jennifer Marohnic ◽  
Robert Geneve ◽  
Jack W. Buxton
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Dry Weight ◽  
Leaf Water ◽  
Root Numbers ◽  
Relative Water ◽  
Leaf Relative Water Content ◽  
Initial Root

Capillary mats were used to vary the water content in oasis blocks during mist propagation of chrysanthemum cuttings. Mats placed on the surface of the propagation bench extended over the edge of the bench and downward a distance of either 0 or 20 cm. Oasis blocks with chrysanthemum cuttings `Boaloi' and `Salmon Charm' were placed on mats under intermittent mist (10 seconds every 5 minutes) between 5 am and 8 pm. Relative water content, mL of water/gram oasis, and leaf water potential were measured at noon every 5 days. After 26 days number of roots per cutting was evaluated. Water content in the oasis block was reduced by 49% (450 to 219 mL/g dry weight of oasis) by hanging the capillary mat 20 cm over the edge of the bench compared to 0 cm treatment. Cuttings showed an increase in leaf relative water content from 49% and 51% at day 1 to 65% and 71% by day 11 for `Boaloi' and `Salmon Charm', respectively. Following initial root formation, leaf relative water content increased to 85%. Over the course of the experiment `Boaloi' and `Salmon Charm' showed an average reduction in leaf water potential of 0.14 and 0.08 MPA, respectively. `Boaloi' showed overall higher root numbers than `Salmon Charm'; however, no difference in rooting between mat treatments was observed.

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