scholarly journals Temperature and evaporative demand drive variation in stomatal and hydraulic traits across grape cultivars

2020 ◽  
Author(s):  
M K Bartlett ◽  
G Sinclair
Keyword(s):  
Stomatal Closure ◽  
Reproductive Traits ◽  
Growing Season ◽  
Crop Productivity ◽  
Evaporative Demand ◽  
Trait Variation ◽  
Plant Resource ◽  
Lower Maximum ◽  
Embolism Resistance ◽  
Maximum Stomatal Conductance

Abstract Selection for crop cultivars has largely focused on reproductive traits, while the impacts of global change on crop productivity are expected to depend strongly on the vegetative physiology traits that drive plant resource use and stress tolerance. We evaluated relationships between physiology traits and growing season climate across winegrape cultivars to characterize trait variation across European growing regions. We compiled values from the literature for seven water use and drought tolerance traits and growing season climate. Cultivars with a lower maximum stomatal conductance were associated with regions with a higher mean temperature and mean and maximum vapor pressure deficit (VPD) (r 2 = 0.39 – 0.65, P < 0.05, N = 14 – 29). Cultivars with greater stem embolism resistance and more anisohydric stomatal behavior (i.e., a more negative water potential threshold for 50% stomatal closure) were associated with cooler regions (r 2 = 0.48 – 0.72, P < 0.03, N = 10 – 29). Overall, cultivars grown in warmer, drier regions exhibited traits that would reduce transpiration and conserve soil water longer into the growing season, but potentially increase stomatal and temperature limitations on photosynthesis under future, hotter conditions.

scholarly journals Limiting transpiration rate in high evaporative demand conditions to improve Australian wheat productivity

2021 ◽  
Author(s):  
Brian Collins ◽  
Scott Chapman ◽  
Graeme Hammer ◽  
Karine Chenu
Keyword(s):  
Transpiration Rate ◽  
Production Systems ◽  
Water Productivity ◽  
Biomass Accumulation ◽  
Climate Scenario ◽  
Grain Filling ◽  
Crop Productivity ◽  
Evaporative Demand ◽  
Lysimeter Experiment ◽  
Grain Filling Period

Abstract Limited-transpiration rate at high evaporative demand (‘LTR’ trait) has potential to improve drought adaptation, crop water productivity and food security. The quantification of the implications of LTR for water consumption, biomass accumulation and yield formation requires the use of dynamic crop modelling to simulate physiological and environmental processes and interactions in target environments. Here, a new transpiration module was developed for the Agricultural Production Systems sIMulator (APSIM NextGen) and used to simulate atmospheric and edaphic water stress on wheat crops. This module was parameterised with (i) data from a lysimeter experiment assessing genotypic variability in the LTR trait for four genotypes contrasting in transpiration efficiency, and with (ii) a more pronounced response to high evaporative demand. The potential of the LTR trait for improving crop productivity was investigated across the Australian wheatbelt over 1989-2018. The LTR trait was simulated to allow an increase in national yield by up to 2.6%, mostly due to shift in water use pattern, alleviation of water deficit during grain filling period and a higher harvest index. Greatest productivity gains were found in the northeast (4.9%, on average) where heavy soils allow the conserved water with the LTR trait to be available later at more critical stages. The effect of the LTR trait on yield was enhanced under the future climate scenario, particularly in the northeast. Limiting transpiration at high evaporative demands appears to be a promising trait for selection by breeders, especially in drought-prone environments where crops heavily rely on stored soil moisture.

Anisohydric water use behavior links growing season evaporative demand to ring-width increment in conifers from summer-dry environments

Trees ◽  
2018 ◽  
Vol 32 (3) ◽  
pp. 735-749 ◽  
Author(s):  
Steve L. Voelker ◽  
R. Justin DeRose ◽  
Matthew F. Bekker ◽  
Chalita Sriladda ◽  
Nisa Leksungnoen ◽  
...  
Keyword(s):  
Water Use ◽  
Ring Width ◽  
Growing Season ◽  
Evaporative Demand ◽  
Use Behavior

scholarly journals Effects of fragmentation on plant adaptation to urban environments

2017 ◽  
Vol 372 (1712) ◽  
pp. 20160038 ◽  
Author(s):  
Jonathan Dubois ◽  
Pierre-Olivier Cheptou
Keyword(s):  
Reproductive Traits ◽  
Urban Ecosystems ◽  
Terrestrial Ecosystems ◽  
Plant Size ◽  
Urban Environments ◽  
Trait Variation ◽  
Fragmented Habitats ◽  
Dispersal Traits ◽  
Neutral Markers

Urban ecosystems are relatively recent and heavily human-altered terrestrial ecosystems with a surprisingly high diversity of animals, plants and other organisms. Urban habitats are also strongly fragmented and subject to higher temperatures, providing a compelling model for studying adaptation to global change. Crepis sancta (Asteraceae), an annual Mediterranean wasteland weed, occupies fragmented urban environments as well as certain unfragmented landscapes in southern France. We tested for shifts in dispersal, reproductive traits and size across a rural–urban gradient to learn whether and how selection may be driving changes in life history in urban and fragmented habitats. We specifically compared the structure of quantitative genetic variation and of neutral markers (microsatellites) between urban and rural and between fragmented and unfragmented habitats. We showed that fragmentation provides a better descriptor of trait variation than urbanization per se for dispersal traits. Fragmentation also affected reproductive traits and plant size though one rural population did conform to this scheme. Our study shows the role of fragmentation for dispersal traits shift in urban environments and a more complex pattern for other traits. We discuss the role of pollinator scarcity and an inhospitable matrix as drivers of adaptation. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’.

scholarly journals Evapotranspiration from a riparian fen wetland

2005 ◽  
Vol 36 (2) ◽  
pp. 121-135 ◽  
Author(s):  
H.E. Andersen ◽  
S. Hansen ◽  
H. E. Jensen
Keyword(s):  
Driving Forces ◽  
Radiant Energy ◽  
Vapour Pressure Deficit ◽  
Open Water ◽  
Absolute Magnitude ◽  
Growing Season ◽  
Agricultural Landscapes ◽  
Water Evaporation ◽  
Evaporative Demand ◽  
Fine Grained

Evapotranspiration rates were measured in a riparian fen wetland dominated by vascular vegetation and surrounded by open agricultural areas and forests. The wetland is situated on a floodplain in central Denmark. Measurements were taken throughout the growing season (April–September) of 1999. Evapotranspiration rates were higher than those published for most other wetland types, with an average of 3.6 mm d−1 during the growing season and a peak rate of 5.6 mm d−1. Daily average evapotranspiration was 110% of Penman's potential open water evaporation. Evapotranspiration was the dominant sink in the energy balance of the wetland studied. During the day, evapotranspiration accounted for 82% of the available radiant energy, Rn. Due to the presence of deposited fine-grained sediments, soil-water availability was kept high at all times which resulted in moderate canopy resistances, rc (overall mean =32 s m−1). Evapotranspiration was controlled by a combination of driving forces: Rn, saturation vapour pressure deficit, D, and rc. It is hypothesized that the results presented in this study are conditioned by the proximity of the wetland to drier upland areas. During periods with high evaporative demand and low precipitation, warm, dry air is formed over the upland areas and wetland evapotranspiration rates are enhanced by local advection. Indicative evidence for the hypothesis is presented. Although the absolute magnitude of the results reported is only directly relevant to similar sites in Denmark, the processes and controls described are considered to be representative of riparian wetlands subjected to frequent flooding and/or with a high groundwater table, with vascular vegetation, and which are narrow corridors in open agricultural landscapes.

Productivity and water relations of field-grown cashew: a comparison of sprinkler and drip irrigation

2001 ◽  
Vol 41 (5) ◽  
pp. 663 ◽  
Author(s):  
S. J. Blaikie ◽  
E. K. Chacko ◽  
P. Lu ◽  
W. J. Müller
Keyword(s):  
Linear Relationship ◽  
Surface Area ◽  
Drip Irrigation ◽  
Root Zone ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Dry Season ◽  
Water Application ◽  
Evaporative Demand ◽  
Tropical Regions

Cashew is an emerging crop in the seasonally ‘wet–dry’ tropical regions of northern Australia. In North Queensland flowering and fruiting of cashew coincides with the dry season (May–November). During this period growers sprinkler irrigate at 500 L/tree.week. A 3-year (1996–98) experiment compared this strategy with alternatives, including no irrigation or drip irrigation in which 115 or 230 L/tree.week was applied by drippers placed near the tree trunk and near the canopy drip line throughout the dry season. Measurements of soil water to 1.3 m, leaf gas exchange, chlorophyll fluorescence, tree sap flow and yield were made. Data collected in the first 2 years showed that the water requirement of the trees increased progressively as the crop load and evaporative demand increased during the dry season. During the final year of the study, additional sprinkler and drip treatments, in which water applications were progressively increased during the dry season, were introduced. The productivity of cashew in this experiment was strongly influenced by irrigation treatments, ranging (over all years) from 42 to 160 g nut/m 2 canopy surface area. Depletion of plant-available water in the root zone was associated with a reduction in photosynthesis mediated by partial stomatal closure. These effects of soil drying were evident in all irrigated treatments during the mid and late stages of the dry season but were more severe in treatments receiving the least water. When irrigation was withheld until the mid-stage of the dry season the trees had similar yields to those that were irrigated throughout, emphasising the importance of providing adequate irrigation between nut set and harvest. When rainfall from January to September in each year of the study was taken into account, there was a strong linear relationship between nut yield and water applied (rainfall + irrigation), with each extra kilolitre of water applied resulting in about 6 extra g nut/m 2 canopy surface area. This linear relationship was based on water application in the range 25–50 kL per season. It is possible that if the seasonal water application had exceeded 50 kL the marginal response to extra water may have diminished. Using drippers was slightly more efficient than sprinklers, with drip-irrigated trees requiring about 5% less water applied to achieve a given nut yield. In years when rainfall is average, and subject to other economic factors, growers in North Queensland should aim to irrigate about 500 L/tree.week. In years of low rainfall between January and September it is likely that yield will be improved by applying more irrigation water; high rainfall during these months of the year may reduce the irrigation requirement. In all cases growers should be careful to accurately monitor water applications, particularly when the total (from rainfall + irrigation) exceeds 40 kL/tree for the season.

Stomatal control and the development of water deficit in Engelmann spruce seedlings during drought

1979 ◽  
Vol 9 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Merrill R. Kaufmann
Keyword(s):  
Flux Density ◽  
Stomatal Closure ◽  
Absolute Humidity ◽  
Pressure Potential ◽  
Evaporative Demand ◽  
Xylem Pressure ◽  
Full Sunlight ◽  
Engelmann Spruce ◽  
Xylem Pressure Potential ◽  
The Relationship

The effects of soil drying on water relations of Engelmann spruce (Piceaengelmannii Engelm.) were studied by withholding water from 4-year-old potted seedlings in full sunlight and under a shade screen transmitting 55–60% light. During a period of 2 months, xylem pressure potential, water vapor conductance, and transpirational flux density gradually declined compared with well watered controls, with drying being more rapid in full sunlight. As drying progressed, xylem pressure potential at 0 transpiration (predawn potential) decreased and the slope of the relationship between xylem pressure potential and transpirational flux density became more negative. Hysteresis in the relationship occurred when predawn xylem pressure potential was −6 bars (1 bar = 105 Pa) or lower. Needle conductance during daylight hours decreased as the absolute humidity difference from leaf to air increased but conductances were lower in September than in August for given humidity differences. Xylem pressure potentials between −15 and −19 bars had no clear effect on conductance in August but apparently caused significant stomatal closure in September. Because of humidity-induced stomatal closure, evaporative demand had little effect on transpirational flux density over a broad range of humidity gradient. Thus increased leaf-to-air vapor gradients for transpiration are not always accompanied by increased transpiration.

scholarly journals Response of carbon fluxes to water relations in a savanna ecosystem in South Africa

2008 ◽  
Vol 5 (6) ◽  
pp. 1797-1808 ◽  
Author(s):  
W. L. Kutsch ◽  
N. Hanan ◽  
B. Scholes ◽  
I. McHugh ◽  
W. Kubheka ◽  
...  
Keyword(s):  
South Africa ◽  
Water Relations ◽  
Ecosystem Respiration ◽  
Stomatal Closure ◽  
Growing Season ◽  
Carbon Fluxes ◽  
Dry Season ◽  
Canopy Conductance ◽  
Wet Season ◽  
Eddy Covariance Method

Abstract. The principal mechanisms that connect carbon fluxes with water relations in savanna ecosystems were studied by using eddy covariance method in a savanna ecosystem at Kruger National Park, South Africa. Since the annual drought and rewetting cycle is a major factor influencing the function of savanna ecosystems, this work focused on the close inter-connection between water relations and carbon fluxes. Data from a nine-month measuring campaign lasting from the early wet season to the late dry season were used. Total ecosystem respiration showed highest values at the onset of the growing season, a slightly lower plateau during the main part of the growing season and a continuous decrease during the transition towards the dry season. The regulation of canopy conductance was changed in two ways: changes due to phenology during the course of the growing season and short-term acclimation to soil water conditions. The most constant parameter was water use efficiency that was influenced by VPD during the day but the VPD response curve of water usage did change only slightly during the course of the growing season and decreased by about 30% during the transition from wet to dry season. The regulation of canopy conductance and photosynthetic capacity were closely related. This observation meets recent leaf-level findings that stomatal closure triggers down-regulation of Rubisco during drought. Our results may show the effects of these processes on the ecosystem scale.

Impact of incorporated hay mulch on selected physical, chemical and microbiological properties of a loam soil in Atlantic Canada after five years of continuous potato production

2005 ◽  
Vol 85 (1) ◽  
pp. 161-172 ◽  
Author(s):  
H. W. Rees ◽  
T. L. Chow
Keyword(s):  
Soil Moisture ◽  
Hydraulic Conductivity ◽  
Organic Carbon ◽  
Soil Quality ◽  
Solanum Tuberosum L ◽  
Total Yield ◽  
Growing Season ◽  
Crop Productivity ◽  
Saturated Hydraulic Conductivity ◽  
Soil Productivity

Maintenance of soil quality and crop productivity is a major concern under intensive potato (Solanum tuberosum L.) production. The effects of four consecutive annual applications of 0.00, 2.25, 4.50 and 9.00 t ha-1 wet hay on growing season soil moisture and thermal regimes, soil quality and yield were evaluated on a loamy Orthic Humo-Ferric Podzol between 1995 and 1999. Hay mulching increased soil moisture at the beginning of the growing season by 6.5 to 12.7%, with increases significant until June 24, September 07 and September 20 for the 2.25, 4.50 and 9.00 t ha-1 treatments, respectively. Growing season soil temperature of the 4.50 and 9.00 t ha-1 treatments were lower than control, but only by −0.2 and −0.8°C, respectively. Hay mulching increased soil organic carbon (SOC) of the plow layer (0–25 cm), which increased biological activity resulting in better soil aggregation with more macropores, faster saturated hydraulic conductivity and reduced bulk density. Soil air CO2 concentration was significantly correlated to SOC content, aggregation, porosity and saturated hydraulic conductivity. Hay mulching at 2.25 and 4.50 t ha-1 increased total potato yield over that of the unmulched control by 11–14%, but was insufficient to maintain soil productivity. Hay mulching at 9.00 t ha-1 may have been excessive in terms of crop yield as it showed no total yield benefits. Key words: Organic carbon, CO2 concentration, aggregates, porosity

scholarly journals How does soil water availability control phytotoxic O<sub>3</sub> dose to montane pines? Modelling and experimental study from two contrasting climatic regions in Europe

2017 ◽  
Author(s):  
Svetlana Bičárová ◽  
Zuzana Sitková ◽  
Hana Pavlendová ◽  
Peter Fleischer Jr. ◽  
Peter Fleischer Sr. ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Stomatal Closure ◽  
Growing Season ◽  
Climatic Conditions ◽  
Moisture Regime ◽  
Mediterranean Forests ◽  
Climatic Regions ◽  
Soil Moisture Regime ◽  
Swiss Stone Pine ◽  
The Mediterranean

Abstract. Montane forests are exposed to high ambient ozone (O3) concentrations that may adversely affect physiological processes in internal cells when O3 molecules enter the plants through the stomata. This study addresses the model results of Phytotoxic Ozone Dose metric (POD) based on estimation of stomatal O3 flux to dwarf mountain pine (Pinus mugo) and Swiss stone pine (Pinus cembra). We focused on two different bioclimatic regions: (1) the temperate mountain forests in the High Tatra Mts (SK–HT) of the Western Carpathians, and (2) the Mediterranean forests of the Alpes–Mercantour (FR–Alp) in the Alpes–Maritimes. Field measurement of O3 concentration and meteorological data incorporated into deposition model DO3SE showed lower O3 flux in FR–Alp than in SK–HT plots for the 2016 growing season. Model outputs showed that soil humidity play a key role in stomatal O3 uptake by montane pines at the alpine timberline. We found that temperate climatic conditions in SK–HT with sufficient precipitation did not limit stomatal conductivity and O3 uptake of P. mugo and P. cembra. On the other hand, the Mediterranean mountain climate characterised by warm and dry summer reduced stomatal conductance of pines in FR–Alp. POD without threshold limitation i.e. POD0 as a recently developed biologically sounded O3 metric varied near around and below critical level (CLef) depending upon different conditions of sunshine exposure in SK–HT plots. Field observation at these plots showed relatively weak visible O3 injury on P. cembra (2 % and 7 %) when compared with P. mugo (8 % and 18 %) for one year (C+1) and two year (C+2) old needles, respectively. Despite of low POD0 values, clearly below CLef, the highest level of visible O3 damage on average from 10 % (C+1) to 25 % (C+2) was observed on P. cembra needles in Mediterranean (FR–Alp) area. Further research is needed to clarify the effect of real soil moisture regime on stomatal closure in dry areas (FR–Alp) and resistance of pine species against visible O3 injury in wet subalpine zones (SK–HT). More attention should be paid to O3 fluxes covering a year-round growing season as well as intra-daily dynamics, especially the night hours, since these time spans appear to play significant role in O3 uptake by mountain conifers.

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