An assessment of potato sap flow as affected by soil water status, solar radiation and vapour pressure deficit

1999 ◽  
Vol 79 (2) ◽  
pp. 245-253 ◽  
Author(s):  
R. Gordon ◽  
D. M. Brown ◽  
A. Madani ◽  
M. A. Dixon
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Vapour Pressure ◽  
Sap Flow ◽  
Water Status ◽  
Vapour Pressure Deficit ◽  
Potato Cultivars ◽  
Rapid Decline ◽  
Plant Variation ◽  
Flow Monitoring

Water-use of three field-grown potato cultivars (Atlantic, Monona and Norchip) was examined using a commercially available sap flow monitoring system over three consecutive growing seasons. The objectives of the investigation were to utilize the sap flow system to assess the water use of three field-grown potato cultivars. This included an assessment of the relationship between environmental conditions, water status and measured sap flow including the plant-to-plant variation in sap flow and an evaluation of relative transpiration in relation to the soil water status.Each cultivar maintained daily sap flow close to the atmospheric potential transpiration until approximately 70% of the available water was depleted. Under conditions where the soil was drier (>70% depleted), Monona potato plants exhibited a more rapid decline in transpiration than Norchip and Atlantic.Hourly sap flow rates were closely related to solar irradiance, especially under well-watered conditions, with no apparent light saturation point. Vapour pressure deficit effects on sap flow were less pronounced, although maximum vapour pressure deficits encountered were only 2 kPa. Key words: Water use, sap flow, transpiration, potato

Partial rootzone drying and deficit irrigation increase stomatal sensitivity to vapour pressure deficit in anisohydric grapevines

2010 ◽  
Vol 37 (2) ◽  
pp. 128 ◽  
Author(s):  
Marisa J. Collins ◽  
Sigfredo Fuentes ◽  
Edward W. R. Barlow
Keyword(s):  
Water Use ◽  
Vapour Pressure ◽  
Sap Flow ◽  
Deficit Irrigation ◽  
Stomatal Closure ◽  
Vapour Pressure Deficit ◽  
Vitis Vinifera L ◽  
Long Distance ◽  
Stomatal Sensitivity ◽  
Partial Rootzone Drying

The aim of this study was to investigate how alternative irrigation strategies affected grapevine (Vitis vinifera L.) stomatal response to atmospheric vapour pressure deficit (VPD). In two sites, application of partial rootzone drying (PRD) at 90–100% of crop evapotranspiration (ETc) increased stomatal sensitivity of Shiraz (Syrah) grapevines to high VPD compared with control vines irrigated with the same amount of water but applied on both sides of the vine. PRD significantly reduced vine water use (ESF) measured as sap flow and in dry conditions increased the depth of water uptake from the soil profile. In both experiments, PRD reduced vine water use by up to 50% at moderate VPD (~3 kPa) compared with control vines irrigated at the same level. In the same vines, the response to PRD applied at 100% ETc and deficit irrigation applied at 65% ETc was the same, increasing stomatal sensitivity to VPD and decreasing sap flow. Hydraulic signalling apparently did not play a role in changing stomatal sensitivity as there was no difference in stem water potentials between any of the treatment (PRD and DI) and control vines. This suggests that a long distance root-based chemical signal such as ABA may be responsible for the changes in stomatal behaviour. Shiraz grapevines have previously been classified as anisohydric-like, but application of PRD and DI increased stomatal closure in response to conditions of high evaporative demand making the vines behave in a more isohydric-like manner.

scholarly journals The dependence of water potential in shoots of <i>Picea abies</i> on air and soil water status

1998 ◽  
Vol 16 (4) ◽  
pp. 470-476 ◽  
Author(s):  
A. Sellin
Keyword(s):  
Picea Abies ◽  
Water Potential ◽  
Soil Water ◽  
Vapour Pressure ◽  
Water Status ◽  
Vapour Pressure Deficit ◽  
Plant Ecology ◽  
Evaporative Demand ◽  
Leaf Water Status ◽  
Water Losses

Abstract. Where there is sufficient water storage in the soil the water potential (Ψx) in shoots of Norway spruce [Picea abies (L.) Karst.] is strongly governed by the vapour pressure deficit of the atmosphere, while the mean minimum values of Ψx usually do not drop below –1.5 MPa under meteorological conditions in Estonia. If the base water potential (Ψb) is above –0.62 MPa, the principal factor causing water deficiency in shoots of P. abies may be either limited soil water reserves or atmospheric evaporative demand depending on the current level of the vapour pressure deficit. As the soil dries the stomatal control becomes more efficient in preventing water losses from the foliage, and the leaf water status, in turn, less sensitive to atmospheric demand. Under drought conditions, if Ψb falls below –0.62 MPa, the trees' water stress is mainly caused by low soil water availability. Further declines in the shoot water potential (below –1.5 MPa) can be attributed primarily to further decreases in the soil water, i.e. to the static water stress.Key words. Hydrology (evapotranspiration · plant ecology · soil moisture).

Vapour pressure deficit aids the interpretation of cotton canopy temperature response to water deficit

2014 ◽  
Vol 41 (5) ◽  
pp. 535 ◽  
Author(s):  
Warren C. Conaty ◽  
James R. Mahan ◽  
James E. Neilsen ◽  
Greg A. Constable
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Vapour Pressure ◽  
Water Status ◽  
Canopy Temperature ◽  
Vapour Pressure Deficit ◽  
Irrigation Scheduling ◽  
Plant Water ◽  
Stress Detection ◽  
Water Fraction

Crop canopy temperature (Tc) is coupled with transpiration, which is a function of soil and atmospheric conditions and plant water status. Thus, Tc has been identified as a real-time, plant-based tool for crop water stress detection. Such plant-based methods theoretically integrate the water status of both the plant and its environment. However, previous studies have highlighted the limitations and difficulty of interpreting the Tc response to plant and soil water stress. This study investigates the links between cotton Tc, established measures of plant water relations and atmospheric vapour pressure deficit (VPDa). Concurrent measures of carbon assimilation (A), stomatal conductance (gs), leaf water potential (Ψl), soil water (fraction of transpirable soil water (FTSW)) and Tc were conducted in surface drip irrigated cotton over two growing seasons. Associations between A, gs, Ψl, FTSW and Tc are presented, which are significantly improved with the inclusion of VPDa. It was concluded that utilising the strong associations between Ψl, VPDa and Tc, an adjustment of 1.8°C for each unit of VPDa should be made to the critical Tc for irrigation. This will improve the precision of irrigation in Tc based irrigation scheduling protocols. Improved accuracy in water stress detection with Tc, and an understanding of the interaction the environment plays in this response, can potentially improve the efficiency of irrigation.

High vapour pressure deficit and low soil water availability enhance shoot growth responses of a C4 grass (Panicum coloratum cv. Bambatsi) to CO2 enrichment

1998 ◽  
Vol 25 (3) ◽  
pp. 287 ◽  
Author(s):  
Saman P. Seneweera ◽  
Oula Ghannoum ◽  
Jann Conroy
Keyword(s):  
Soil Water ◽  
Elevated Co2 ◽  
Vapour Pressure ◽  
Shoot Growth ◽  
Vapour Pressure Deficit ◽  
C4 Grasses ◽  
Growth Responses ◽  
High Co2 ◽  
C4 Grass ◽  
Shoot Mass

The hypothesis that shoot growth responses of C4 grasses to elevated CO2 are dependent on shoot water relations was tested using a C4 grass, Panicum coloratum (NAD-ME subtype). Plants were grown for 35 days at CO2 concentrations of 350 or 1000 µL CO2 L-1. Shoot water relations were altered by growing plants in soil which was brought daily to 65, 80 or 100% field capacity (FC) and by maintaining the vapour pressure deficit (VPD) at 0.9 or 2.1 kPa. At 350 µL CO2 L-1, high VPD and lower soil water content depressed shoot dry mass, which declined in parallel at each VPD with decreasing soil water content. The growth depression at high VPD was associated with increased shoot transpiration, whereas at low soil water, leaf water potential was reduced. Elevated CO2 ameliorated the impact of both stresses by decreasing transpiration rates and raising leaf water potential. Consequently, high CO2 approximately doubled shoot mass and leaf length at a VPD of 2.1 kPa and soil water contents of 65 and 80% FC but had no effect on unstressed plants. Water use efficiency was enhanced by elevated CO2 under conditions of stress but this was primarily due to increases in shoot mass. High CO2 had a greater effect on leaf growth parameters than on stem mass. Elevated CO2 increased specific leaf area and leaf area ratio, the latter at high VPD only. We conclude that high CO2 increases shoot growth of C4 grasses by ameliorating the effects of stress induced by either high VPD or low soil moisture. Since these factors limit growth of field-grown C4 grasses, it is likely that their biomass will be enhanced by rising atmospheric CO2 concentrations.

scholarly journals Double-Double Row Planting Mode at Deficit Irrigation Regime Increases Winter Wheat Yield and Water Use Efficiency in North China Plain

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1315
Author(s):  
Xun Bo Zhou ◽  
Guo Yun Wang ◽  
Li Yang ◽  
Hai Yan Wu
Keyword(s):  
Winter Wheat ◽  
Soil Water ◽  
Water Use ◽  
Deficit Irrigation ◽  
Water Status ◽  
Row Spacing ◽  
Soil Water Depletion ◽  
Double Row ◽  
Water Depletion ◽  
Use Efficiency

Low water availability coupled with poor planting method has posed a great challenge to winter wheat (Triticum aestivum L.) productivity. To improve productivity and water use efficiency (WUE) under deficit irrigation, an effective water-saving technology that is characterized by three planting modes has been developed (uniform with 30-cm row spacing (U), double-double row spacing of 5 cm (DD), and furrow-ridge row spacing of alternated 20 cm and 40 cm (F)) combined with three irrigation regimes (50 mm water each at growth stage 34 (GS34) and GS48 (W1), and 100 mm water at GS48 (W2), or 100 mm each water at GS34 and GS48 (W3)). Results showed that DD increased yield by 9.7% and WUE by 12.6% due to higher soil water status and less soil water depletion and evapotranspiration compared with U. Although the soil water status, soil water depletion, evapotranspiration, and yield increased with increasing irrigation amount, more soil water depletion and evapotranspiration resulted in low WUE. The deficit irrigation was beneficial for improving WUE as W1 had significantly increased yield by 5.4% and WUE by 7.1% compared with W2. Yield and evapotranspiration showed a quadratic dynamic equation indicating that yield increased with increasing evapotranspiration. Considering WUE and relatively higher yield under deficit water, W1 combined with DD is suggested to be a good management strategy to be applied in winter wheat of water-scarce regions.

Effect of Temperature, Vapour-Pressure Deficit and Irradiance on Transpiration Rates of Maize, Paspalum, Westerwolds and Perennial Ryegrasses, Peas, White Clover and Lucerne

1977 ◽  
Vol 4 (6) ◽  
pp. 889 ◽  
Author(s):  
BJ Forde ◽  
KJ Mitchell ◽  
EA Edge
Keyword(s):  
Water Use ◽  
Transpiration Rate ◽  
White Clover ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Effect Of Temperature ◽  
Climate Conditions ◽  
Growth Environment ◽  
Temperature Regimes ◽  
C3 Species

Rates of water use [g H2O (g dry wt leaf)-1 h-1] of young plants of maize, paspalum, perennial ryegrass, Westerwolds ryegrass, peas, white clover and lucerne were measured during the day under controlled climate conditions with ample water available to the plant. Plants were grown and observations made with day/night temperatures of 32.5/27.5°C, 27.5/22.5°, 22.5/17.5°, and 17.5/12.5°C with a day/night vapour pressure deficit (VPD) of the air of 10/2mbar. Water use measurements were also made at 27.5/22.5° and 17.5/12.5°C under day/night VPD regimes of 5/2 and 15/2 mbar. Irradiance during the 12-h day was 170 W m-2 (400-700 nm). Further water use determinations were made at the four temperature regimes under 10/2 mbar VPD and an irradiance of 60 W m-2 (400-700 nm). For a given species, transpiration rates increased with temperature at constant VPD under both irradiance environments, by factors ranging from 1.4 to 2.3. Transpiration rates of maize and paspalum (C4) were lower at a given temperature than were the rates of the C3 species, while lucerne and clover had the highest rates. Water use by lucerne was 2.5 to 3.5 times that of maize. Transpiration rates of maize and paspalum were lower under 60 W m-2 than under 170 W m-2 but irradiance had little effect on transpiration rate of the C3 species. Though transpiration rate generally increased with increasing VPD, the difference in rates between plants at 5 mbar and 10 mbar VPD was much greater than between 10 mbar and 15 mbar. The physiological adaption of different species to their growth environment is discussed, and the implications of the results with reference to water loss by young, single-spaced plants in the field is outlined.

Water Use by Legumes and its Effect on Soil Water Status

Crop Science ◽  
1989 ◽  
Vol 29 (5) ◽  
pp. 1212-1216 ◽  
Author(s):  
M. Badaruddin ◽  
D. W. Meyer
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Water Status ◽  
Soil Water Status

Seasonal changes in the water status of three woody legumes from the Atlantic forest, Caratinga, Brazil

2000 ◽  
Vol 16 (1) ◽  
pp. 21-32 ◽  
Author(s):  
J. P. Lemos Filho ◽  
C. V. Mendonça Filho
Keyword(s):  
Atlantic Forest ◽  
Vapour Pressure ◽  
Seasonal Changes ◽  
Water Status ◽  
Linear Equations ◽  
Canopy Cover ◽  
Correlation Coefficients ◽  
Vapour Pressure Deficit ◽  
Strong Relationship ◽  
Woody Legumes

The Atlantic forest of Brazil is considered to be a high priority for conservation in South America. Despite its importance, few phenological and ecophysiological data are available for plants of this area. In this study the seasonal changes in the water potentials (Ψ) and the phenological behaviour of three woody legumes are related to environmental conditions, particularly air vapour pressure deficit (VPD). The values of Ψ at predawn were greater than −0.75 MPa for all species even during the dry season (May–September). The minimal daily value of Ψ was −3.8 MPa. The maximum daily amplitude of Ψ (Δ parameter) was correlated with the air vapour pressure deficit, showing high correlation coefficients in linear equations. A high recovery rate of Ψ after rain (greater than 0.80) was registered for all species, suggesting a high hydraulic conductivity. The high values of Ψ at predawn during the year and the strong relationship between the daily amplitude of Ψ and VPD suggested that the changes in the canopy cover are related more to atmospheric drought than to soil water deficit.

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