Water Relations of the Banana. III. Effects of Controlled Water Stress on Water Potential, Transpiration, Photosynthesis and Leaf Growth.

1990 ◽  
Vol 17 (1) ◽  
pp. 79 ◽  
Author(s):  
J Kallarackal ◽  
JA Milburn ◽  
DA Baker
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Growth ◽  
Water Status ◽  
Stomatal Closure ◽  
Leaf Temperature ◽  
Gas Exchange Parameters ◽  
Applied Water ◽  
Potential Transpiration ◽  
Exchange Parameters

Banana suckers were grown in the glasshouse under controlled environmental conditions. Water potentials were measured on plants 6-12 months old using the solute potential of the latex as a guide. The diurnal fluctuations in water potential were monitored along with measurements of transpiration rate, leaf conductance, leaf temperature, assimilation rate and leaf growth rate. Concurrent measurements were made of water potential, transpiration and other gas exchange parameters under rapidly and slowly applied water stress. Stomatal closure was almost complete after 10 days of rapid stress whereas, under slow stress, closure was delayed for a total of 30 days. Stomatal closure was accompanied by a reduction in transpiration and photosynthesis. However, the water potential of the plant was never more negative than -0.35 MPa even when the water stress was severe. The growth of the plant, as evaluated from the emergence of new leaves, was stopped at the same time as photosynthesis. The implications of these observations on the ability of banana to utilise dwindling supplies of water are discussed. The use of latex solute potential as a tool to understand the water status of the plant is further explained.

Effect of Water Stress on Stomatal Conductance and Leaf Water Relations of Leaves Along Current-Year Branches of Peach

1989 ◽  
Vol 16 (6) ◽  
pp. 549 ◽  
Author(s):  
SL Steinberg ◽  
MJ Mcfarland ◽  
JC Miller
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Status ◽  
Stomatal Closure ◽  
Water Flux ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Mature Leaves ◽  
Water Potentials

A gradation, that reflects the maturity of the leaves, exists in the leaf water, osmotic and turgor potential and stomatal conductance of leaves along current and 1-year-old branches of peach. Predawn leaf water potentials of immature folded leaves were approximately 0.24 MPa lower than mature leaves under both well-watered and dry conditions. During the daytime the leaf water potential of immature leaves reflected the water potential produced by water flux for transpiration. In well- watered trees, mature and immature unfolded leaves had a solute potential at least 0.5 MPa lower than immature folded leaves, resulting in a turgor potential that was approximately 0.8 MPa higher. The turgor requirement for growth appeared to be much less than that maintained in mature leaves. As water stress developed and leaf water potentials decreased, the osmotic potential of immature folded leaves declined to the level found in mature leaves, thus maintaining turgor. In contrast, mature leaves showed little evidence of turgor maintenance. Stomatal conductance was lower in immature leaves than in fully mature leaves. With the onset of water stress, conductance of mature leaves declined to a level near that of immature leaves. Loss of turgor in mature leaves may be a major factor in early stomatal closure. It was concluded that osmotic adjustment played a role in maintenance of a leaf water status favorable for some growth in water-stressed immature peach leaves.

scholarly journals Leaf Water Storage and Robustness to Intermittent Drought: A Spatially Explicit Capacitive Model for Leaf Hydraulics

2021 ◽  
Vol 12 ◽  
Author(s):  
Yongtian Luo ◽  
Che-Ling Ho ◽  
Brent R. Helliker ◽  
Eleni Katifori
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Environmental Changes ◽  
Water Status ◽  
Stomatal Closure ◽  
Water Storage ◽  
Leaf Water ◽  
Spatially Explicit ◽  
Air Humidity ◽  
Leaf Water Status

Leaf hydraulic networks play an important role not only in fluid transport but also in maintaining whole-plant water status through transient environmental changes in soil-based water supply or air humidity. Both water potential and hydraulic resistance vary spatially throughout the leaf transport network, consisting of xylem, stomata and water-storage cells, and portions of the leaf areas far from the leaf base can be disproportionately disadvantaged under water stress. Besides the suppression of transpiration and reduction of water loss caused by stomatal closure, the leaf capacitance of water storage, which can also vary locally, is thought to be crucial for the maintenance of leaf water status. In order to study the fluid dynamics in these networks, we develop a spatially explicit, capacitive model which is able to capture the local spatiotemporal changes of water potential and flow rate in monocotyledonous and dicotyledonous leaves. In electrical-circuit analogs described by Ohm's law, we implement linear capacitors imitating water storage, and we present both analytical calculations of a uniform one-dimensional model and numerical simulation methods for general spatially explicit network models, and their relation to conventional lumped-element models. Calculation and simulation results are shown for the uniform model, which mimics key properties of a monocotyledonous grass leaf. We illustrate water status of a well-watered leaf, and the lowering of water potential and transpiration rate caused by excised water source or reduced air humidity. We show that the time scales of these changes under water stress are hugely affected by leaf capacitance and resistances to capacitors, in addition to stomatal resistance. Through this modeling of a grass leaf, we confirm the presence of uneven water distribution over leaf area, and also discuss the importance of considering the spatial variation of leaf hydraulic traits in plant biology.

Photosynthesis in Coffea arabica. II. Effects of Water Stress

1980 ◽  
Vol 16 (1) ◽  
pp. 21-27 ◽  
Author(s):  
D. Kumar ◽  
Larry L. Tieszen
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Coffea Arabica ◽  
Water Status ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Plant Water

SUMMARYExperiments were carried out to relate soil moisture to leaf water potential (Ψ1), and to determine the effects of varying Ψ1, on leaf conductances and photosynthesis in coffee. Stomatal conductance was maximum at 0900 h, but plants growing in drier soil showed marked mid-day stomatal closure. After 1500 h, stomata began closing although plant water status improved. Photosynthesis in relation to changing Ψ1 appeared to exhibit roughly three different rates. At the fixed experimental temperature (25°C) low Ψ1 reduced photosynthesis throughits influence on stomata, but under field conditions low Ψ1 and an accompanying rise in temperature could lower the rate by lowering both mesophyll and stomatal conductances.

Stomatal Behaviour of Kenaf and Sorghum in a Semiarid Tropical Environment. II. During the Day

1980 ◽  
Vol 7 (5) ◽  
pp. 621 ◽  
Author(s):  
RC Muchow ◽  
MJ Fisher ◽  
MM Ludlow ◽  
RJK Myers
Keyword(s):  
Water Stress ◽  
Feedback Control ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Stomatal Closure ◽  
Controlled Environment ◽  
Saturation Deficit ◽  
Stomatal Behaviour

The influence of leaf water potential (Ψl), saturation deficit (δe), and temperature on stornatal conductance (gs) of kenaf and sorghum was determined at non-limiting quantum fluxes both at high and low soil water status in the field, and under controlled environment conditions. Sorghum stomata closed in response to Ψl in a manner consistent with the classical feedback control, while kenaf stomata responded directly to δe, independently of Ψl. The rate of decrease of gs of kenaf with increasing δe was greater at higher temperatures. Also the stomata of stressed kenaf were less sensitive to δe than those of the well-watered crop due to the limitation in degree of stomatal opening imposed by water stress. The degree of stomatal adjustment in kenaf was also assessed. In the stressed kenaf, the Ψl at half the maximum gs was c. 0.17 MPa lower and gs was more sensitive to decreases in Ψl, than in the well watered control. However, there was little difference in the Ψl at 95% stomatal closure.

scholarly journals The Effect of Grapevine Age (Vitis vinifera L. cv. Zinfandel) on Phenology and Gas Exchange Parameters over Consecutive Growing Seasons

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 311
Author(s):  
Vegas Riffle ◽  
Nathaniel Palmer ◽  
L. Federico Casassa ◽  
Jean Catherine Dodson Peterson
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Management Practices ◽  
Leaf Water ◽  
Sugar Accumulation ◽  
Gas Exchange Parameters ◽  
Growing Season Length ◽  
Growing Seasons ◽  
Exchange Parameters

Unlike most crop industries, there is a strongly held belief within the wine industry that increased vine age correlates with quality. Considering this perception could be explained by vine physiological differences, the purpose of this study was to evaluate the effect of vine age on phenology and gas exchange parameters. An interplanted, dry farmed, Zinfandel vineyard block under consistent management practices in the Central Coast of California was evaluated over two consecutive growing seasons. Treatments included Young vines (5 to 12 years old), Control (representative proportion of young to old vines in the block), and Old vines (40 to 60 years old). Phenology, leaf water potential, and gas exchange parameters were tracked. Results indicated a difference in phenological progression after berry set between Young and Old vines. Young vines progressed more slowly during berry formation and more rapidly during berry ripening, resulting in Young vines being harvested before Old vines due to variation in the timing of sugar accumulation. No differences in leaf water potential were found. Young vines had higher mid-day stomatal conductance and tended to have higher mid-day photosynthetic rates. The results of this study suggest vine age is a factor in phenological timing and growing season length.

scholarly journals Hormonal and Hydroxycinnamic Acids Profiles in Banana Leaves in Response to Various Periods of Water Stress

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jalel Mahouachi ◽  
María F. López-Climent ◽  
Aurelio Gómez-Cadenas
Keyword(s):  
Water Stress ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Photosynthetic Performance ◽  
Hydroxycinnamic Acids ◽  
Cinnamic Acids ◽  
Gas Exchange Parameters ◽  
Banana Leaves ◽  
Indole 3 Acetic Acid

The pattern of change in the endogenous levels of several plant hormones and hydroxycinnamic acids in addition to growth and photosynthetic performance was investigated in banana plants (Musa acuminatacv. “Grand Nain”) subjected to various cycles of drought. Water stress was imposed by withholding irrigation for six periods with subsequent rehydration. Data showed an increase in abscisic acid (ABA) and indole-3-acetic acid (IAA) levels, a transient increase in salicylic acid (SA) concentration, and no changes in jasmonic acid (JA) after each period of drought. Moreover, the levels of ferulic (FA) and cinnamic acids (CA) were increased, and plant growth and leaf gas exchange parameters were decreased by drought conditions. Overall, data suggest an involvement of hormones and hydroxycinnamic acids in plant avoidance of tissue dehydration. The increase in IAA concentration might alleviate the senescence of survival leaves and maintained cell elongation, and the accumulation of FA and CA could play a key role as a mechanism of photoprotection through leaf folding, contributing to the effect of ABA on inducing stomatal closure. Data also suggest that the role of SA similarly to JA might be limited to a transient and rapid increase at the onset of the first period of stress.

Estimation water status of the vineyard by calculating multispectral index from satellite images

2021 ◽  
Author(s):  
Marta Rodríguez-Fernández ◽  
María Fandiño ◽  
Xesús Pablo González ◽  
Javier J. Cancela
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Spectral Index ◽  
Satellite Images ◽  
Irrigation System ◽  
Water Status ◽  
Stress Index ◽  
Stem Water Potential ◽  
Stem Water ◽  
Water Potential Measurements

<p>The estimation of the water status in the vineyard, is a very important factor, in which every day the winegrowers show more interest since it directly affects the quality and production in the vineyards. The situation generated by COVID-19 in viticulture, adds importance to tools that provide information of the hydric status of vineyard plants in a telematic way.</p><p>In the present study, the stem water potential in the 2018 and 2019 seasons, is analysed in a vineyard belonging to the Rias Baixas wine-growing area (Vilagarcia de Arousa, Spain), with 32 sampling points distributed throughout the plot, which allows the contrast and validation with the remote sensing methodology to estimate the water status of the vineyard using satellite images.</p><p>The satellite images have been downloaded from the Sentinel-2 satellite, on the closets available dates regarding the stem water potential measurements, carried out in the months of June to September, because this dates are considered the months in which vine plants have higher water requirements.</p><p>With satellite images, two spectral index related to the detection of water stress have been calculated: NDWI (Normalized Difference Water Index) and MSI (Moisture Stress Index). Stem water potential measurements, have allowed a linear regression with both index, to validate the use of these multispectral index to determine water stress in the vineyard.</p><p>Determination coefficients of r<sup>2</sup>=0.62 and 0.67, have been obtained in July and August 2018 and 0.54 in June of 2019 for the NDWI index, as well as values of 0.53 and 0.63 in July 2018 and June 2019 respectively, when it has been analysed the MSI index.</p><p>Between both seasons, the difference observed, that implies slightly greater water stress in 2019, is reflected in the climate conditions during the summer months, with an average accumulated rainfall that doesn’t exceed 46 mm of water. Although, the NDWI index has allowed to establish better relationships in the 2018 season respect to the MSI index and the 2019 season, (r<sup>2</sup>=0.60 NDWI in 2018), as well as greater differences in terms of water stress presented in the vineyard.</p><p>With the spectral index calculated, it has been possible to validate the use of these index for the determination of the water stress of the vineyard plants, as an efficient, fast and less expensive method, which allows the application of an efficient irrigation system in the vineyard.</p>

scholarly journals Interactions between leaf water potential, stomatal conductance and abscisic acid content of orange trees submitted to drought stress

2004 ◽  
Vol 16 (3) ◽  
pp. 155-161 ◽  
Author(s):  
Mara de Menezes de Assis Gomes ◽  
Ana Maria Magalhães Andrade Lagôa ◽  
Camilo Lázaro Medina ◽  
Eduardo Caruso Machado ◽  
Marcos Antônio Machado
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Acid Content ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Orange Trees ◽  
Abscisic Acid Content

Thirty-month-old 'Pêra' orange trees grafted on 'Rangpur' lemon trees grown in 100 L pots were submitted to water stress by the suspension of irrigation. CO2 assimilation (A), transpiration (E) and stomatal conductance (g s) values declined from the seventh day of stress, although the leaf water potential at 6:00 a.m. (psipd) and at 2:00 p.m. (psi2) began to decline from the fifth day of water deficiency. The CO2 intercellular concentration (Ci) of water-stressed plants increased from the seventh day, reaching a maximum concentration on the day of most severe stress. The carboxylation efficiency, as revealed by the ratio A/Ci was low on this day and did not show the same values of non-stressed plants even after ten days of rewatering. After five days of rewatering only psi pd and psi2 were similar to control plants while A, E and g s were still different. When psi2 decreases, there was a trend for increasing abscisic acid (ABA) concentration in the leaves. Similarly, stomatal conductance was found to decrease as a function of decreasing psi2. ABA accumulation and stomatal closure occurred when psi2 was lower than -1.0 MPa. Water stress in 'Pera´ orange trees increased abscisic acid content with consequent stomatal closure and decreased psi2 values.

scholarly journals Physiological parameters to select upland rice genotypes for tolerance to water deficit

2015 ◽  
Vol 50 (7) ◽  
pp. 534-540 ◽  
Author(s):  
Cleber Morais Guimarães ◽  
Luís Fernando Stone ◽  
Adriano Pereira de Castro ◽  
Odilon Peixoto de Morais Júnior
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Upland Rice ◽  
Water Status ◽  
Leaf Temperature ◽  
Physiological Parameters ◽  
Stress Conditions ◽  
Diffusive Resistance ◽  
Susceptible Control ◽  
Rice Genotypes

Abstract: The objective of this work was to evaluate the feasibility of using physiological parameters for water deficit tolerance, as an auxiliary method for selection of upland rice genotypes. Two experiments - with or without water deficit - were carried out in Porangatu, in the state of Goiás, Brazil; the water deficit experiment received about half of irrigation that was applied to the well-watered experiment. Four genotypes with different tolerance levels to water stress were evaluated. The UPLRI 7, B6144F-MR-6-0-0, and IR80312-6-B-3-2-B genotypes, under water stress conditions, during the day, showed lower stomatal diffusive resistance, higher leaf water potential, and lower leaf temperature than the control. These genotypes showed the highest grain yields under water stress conditions, which were 534, 601, and 636 kg ha-1, respectively, and did not differ significantly among them. They also showed lower drought susceptibility index than the other genotypes. 'BRS Soberana' (susceptible control) was totally unproductive under drought conditions. Leaf temperature is a easy-read parameter correlated to plant-water status, viable for selecting rice genotypes for water deficit tolerance.

Development of a Continuous Leaf Monitoring System to Predict Plant Water Status

2017 ◽  
Vol 60 (5) ◽  
pp. 1445-1455 ◽  
Author(s):  
Rajveer S. Dhillon ◽  
Shrini K. Upadhaya ◽  
Francisco Rojo ◽  
Jed Roach ◽  
Robert W. Coates ◽  
...  
Keyword(s):  
Water Stress ◽  
Data Collection ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Leaf Temperature ◽  
Plant Water Status ◽  
Mesh Network ◽  
Plant Water ◽  
Plant Water Stress ◽  
Precision Irrigation

Abstract. There is increased demand for irrigation scheduling tools that support effective use of the limited supply of irrigation water. An efficient precision irrigation system requires water to be delivered based on crop needs by measuring or estimating plant water stress. Leaf temperature is a good indicator of water stress. In this study, a system was developed to monitor leaf temperature and microclimatic environmental variables to predict plant water stress. This system, called the leaf monitor, monitored plant water status by continuously measuring leaf temperature, air temperature, relative humidity, ambient light, and wind conditions in the vicinity of a shaded leaf. The system also included a leaf holder, a solar radiation diffuser dome, and a wind barrier for improved performance of the unit. Controlled wind speed and consistent light conditions were created around the leaf to reduce the effect of nuisance variables on leaf temperature. The leaf monitor was incorporated into a mesh network of wireless nodes for sensor data collection and remote valve control. The system was evaluated for remote data collection in commercial orchards. Experiments were conducted during the 2013 and 2014 growing seasons in walnut () and almond () orchards. The system was found to be reliable and capable of providing real-time visualization of the data remotely, with minimal technical problems. Leaf monitor data were used to develop modified crop water stress index (MCWSI) values for quantifying plant water stress levels. Keywords: Almonds, CWSI, Infrared sensor, Irrigation scheduling, Leaf temperature, Nut crops, Plant water stress, Precision irrigation, Stem water potential, Walnuts, Wireless mesh network.

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