scholarly journals The influence of soil water potential and soil temperature on the seedling emergence of wheat and barley

1986 ◽  
Vol 58 (4) ◽  
pp. 185-190 ◽  
Author(s):  
Markku Tenhovuori
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Uptake ◽  
Seedling Emergence ◽  
Soil Water Potential ◽  
Matric Potential ◽  
Initial Water ◽  
Emergence Period ◽  
Increasing Temperature ◽  
Clear Increase

The time for 50 % emergence of wheat and barley increases linearly with decreasing matric potential. This increase actually begins at matric pressures above pF 2.7. The rise in temperature makes emergence faster with in the range of minimum temperature (3.1°C for wheat and 1.9°C for barley) and the temperature where growth begins to slow down(about 31°C for wheat and 27°C for barley).The optimum range for 50 % emergence was obtained at a matric pressure range of pF 1.3—2.7 or —5.0— —0.20 m (water column) at a temperature of 10°C, which quite well corresponds to the situation in Finland during the emergence period in spring. A clear increase can be observed in the required heat sum for wheat and barley when the soil water potential reaches a critical point which was pF 2.8 or—6.3m for wheat and pF 2.7 or —5.0 m for barley. The total emergence as a function of matric potential for wheat and barley was determined over a period of 30 days at 10°C. In the wet side, pF 1,0 can be considered a limit, the total emergence decreasing with lower values. In the dry side, a corresponding decrease can be noticed in total emergence at pF above 3.0. The water uptake by seeds speeded up with increasing temperature from 10 to 25°C. Radicles of wheat and barley began to appear when the water uptake by the seed was approximately 50—60 % of the initial weight of the seed. The initial water uptake caused by the moistening of the pericarp due to capillarity was about 3 % for wheat and 5 % for barley at a soil water potential of pF 1.2.

scholarly journals Influence of Drought on Foliar Water Uptake Capacity of Temperate Tree Species

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 562 ◽  
Author(s):  
Jeroen D.M. Schreel ◽  
Jonas S. von der Crone ◽  
Ott Kangur ◽  
Kathy Steppe
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Uptake ◽  
Tree Species ◽  
Soil Water Potential ◽  
Future Research ◽  
General Increase ◽  
Foliar Water Uptake ◽  
The Impact ◽  
Key Tree

Foliar water uptake (FWU) has been investigated in an increasing number of species from a variety of areas but has remained largely understudied in deciduous, temperate tree species from non-foggy regions. As leaf wetting events frequently occur in temperate regions, FWU might be more important than previously thought and should be investigated. As climate change progresses, the number of drought events is expected to increase, basically resulting in a decreasing number of leaf wetting events, which might make FWU a seemingly less important mechanism. However, the impact of drought on FWU might not be that unidirectional because drought will also cause a more negative tree water potential, which is expected to result in more FWU. It yet remains unclear whether drought results in a general increase or decrease in the amount of water absorbed by leaves. The main objectives of this study are, therefore: (i) to assess FWU-capacity in nine widely distributed key tree species from temperate regions, and (ii) to investigate the effect of drought on FWU in these species. Based on measurements of leaf and soil water potential and FWU-capacity, the effect of drought on FWU in temperate tree species was assessed. Eight out of nine temperate tree species were able to absorb water via their leaves. The amount of water absorbed by leaves and the response of this plant trait to drought were species-dependent, with a general increase in the amount of water absorbed as leaf water potential decreased. This relationship was less pronounced when using soil water potential as an independent variable. We were able to classify species according to their response in FWU to drought at the leaf level, but this classification changed when using drought at the soil level, and was driven by iso- and anisohydric behavior. FWU hence occurred in several key tree species from temperate regions, be it with some variability, which potentially allows these species to partly reduce the effects of drought stress. We recommend including this mechanism in future research regarding plant–water relations and to investigate the impact of different pathways used for FWU.

Soil water matric potential rather than water content determines drought responses in field-grown lupin (Lupinus angustifolius)

1998 ◽  
Vol 25 (3) ◽  
pp. 353 ◽  
Author(s):  
C.R. Jensen ◽  
V.O. Mogensen ◽  
H.-H. Poulsen ◽  
I.E. Henson ◽  
S. Aagot ◽  
...  
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Root Surface ◽  
Lupinus Angustifolius ◽  
Soil Drying ◽  
Matric Potential ◽  
Aba Content

Drought responses in leaves of lupin (Lupinus angustifolius L., cv. Polonez) were investigated in plants grown in lysimeters either in a sand or in a loam soil in the field. Abscisic acid (ABA) content, water potential (ψl) and conductance to water vapour (gH2O) were determined in leaves of both irrigated plants and in plants exposed to gradual soil drying. Amorning-peak of leaf ABA content was found in both fully watered and droughted plants. During soil drying which, on both soils types, only decreased soil water potential of the upper soil layers, mid-day leaf ABA content increased relative to that in fully irrigated plants before any appreciable decreases occurred in ψl. In the part of the soil profile from which water was taken up (0–60 cm depth), gH2O decreased when the relative available soil water content (RASW) on sand was below 12% and RASW on loam, below 30%. At this point the average soil water matric potential (ψsoil) on sand was less than –0.13 MPa and the fraction of roots in ‘wet’ soil was 0.12, while on loam, the fraction of roots in ‘wet’ soil was 0.44 while y soil was similar to that on sand. A critical leaf ABA content of 300–400 ng/g FW was associated with the onset of stomatal closure on both soil types. We suggest that the initial stomatal closure is controlled by ABA which originates from the roots where its production is closely related to ψsoiland the water potential of the root surface and that ψsoil is a more important parameter than RASW or the fraction of roots in ‘wet’ soil for affecting leaf gas exchange. Further drying on both soils led to further increases in leaf ABA and declines in ψl and gH2O. In order to gain further insight, experiments should be designed which combine signalling studies with simulation studies, which take account of soil water potential, root contact area and water flux when calculating the water status at the root surface in the soil-plant-atmosphere-continuum.

A Model for Predicting Large Crabgrass (Digitaria sanguinalis) Emergence as Influenced by Temperature and Water Potential

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Charles A. King ◽  
Lawrence R. Oliver
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Uptake ◽  
Field Experiments ◽  
Soil Water Potential ◽  
Lag Phase ◽  
Subsequent Increase ◽  
Soil Temperatures ◽  
Emergence Percentage ◽  
Large Crabgrass

Experiments were conducted to evaluate the influence of temperature and water potential on water uptake, germination, and emergence of large crabgrass in order to predict emergence in the field. Water uptake of seed soaked in polyethylene glycol solutions of 0 to −1400 kPa underwent an initial imbibition phase followed by a lag phase and subsequent increase in water content when radicles emerged from the seed. Maximum germination at 15 C was 12% at 0 kPa and 60% at 25 C at 0 to −200 kPa osmotic potential. In the growth chamber, large crabgrass emergence from soil began 2 to 3 d after planting at 30 or 35 C and within 9 to 10 d at 15 C. Maximum emergence of 77 % occurred at 25 C and at a soil water potential of −30 kPa. Emergence percentage decreased as water potential decreased or as temperature increased or decreased. A logistic equation described emergence of large crabgrass at each combination of temperature and soil water potential at which emergence occurred, and a predictive model was developed and validated by field data. In the field, there was little or no emergence at soil temperatures below 15 C or water potentials below −50 to −60 kPa. The model predicted the time of onset of large crabgrass emergence and the time to reach maximum emergence to within 2 to 4 d of that recorded in field experiments. The model also predicted the correct number of flushes of emergence occurring in the field in three of four experiments.

Leaf Gas Exchange and Water Relations of Lupins and Wheat. II. Root and Shoot Water Relations of Lupin During Drought-Induced Stomatal Closure

1989 ◽  
Vol 16 (5) ◽  
pp. 415 ◽  
Author(s):  
CR Jensen ◽  
IE Henson ◽  
NC Turner
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Transport ◽  
Water Uptake ◽  
Water Relations ◽  
Leaf Gas Exchange ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Root Water Uptake ◽  
Leaf Conductance

Plants of Lupinus cosentinii Guss. cv. Eregulla were grown in a sandy soil in large containers in a glasshouse and exposed to drought by withholding water. Under these conditions stomatal closure had previously been shown to be initiated before a significant reduction in leaf water potential was detected. In the experiments reported here, no significant changes were found in water potential or turgor pressure of roots or leaves when a small reduction in soil water potential was induced which led to a 60% reduction in leaf conductance. The decrease in leaf conductance and root water uptake closely paralleled the fraction of roots in wet soil. By applying observed data of soil water and root characteristics, and root water uptake for whole pots in a single-root model, the average water potential at the root surface was calculated. Potential differences for water transport in the soil-plant system, and the resistances to water flow were estimated using the 'Ohm's Law' analogy for water transport. Soil resistance was negligible or minor, whereas the root resistance accounted for 61-72% and the shoot resistance accounted for about 30% of the total resistance. The validity of the measurements and calculations is discussed and the possible role of root- to-shoot communication raised.

EFFECT OF SOIL WATER POTENTIAL AND BULK DENSITY ON WATER UPTAKE PATTERNS AND RESISTANCE TO FLOW OF WATER IN WHEAT PLANTS

1971 ◽  
Vol 51 (2) ◽  
pp. 211-220 ◽  
Author(s):  
S. J. YANG ◽  
E. DE JONG
Keyword(s):  
Water Potential ◽  
Bulk Density ◽  
Soil Water ◽  
Water Uptake ◽  
Water Movement ◽  
Soil Column ◽  
Soil Water Potential ◽  
Moisture Uptake ◽  
The Mathematical Model ◽  
Water Uptake Patterns

Water uptake patterns of wheat plants were studied in a growth chamber by using two soils packed to three different bulk densities. The resistances to water movement in the soil and in the plant were calculated from the mathematical model for water uptake published in the literature. When the capillary potential of the soils was near −⅓ bar, withdrawal of water by plants was relatively small and most of the water was taken from the top 25 cm of the soil column. As soil water potential decreased, water uptake increased progressively toward the lower part of the soil column. The resistance to water movement in the plant increased from the top to the bottom of the root system and increased with increasing bulk density of the soils. For wet soils, unrealistic values were obtained which could be due to the fact that the interaction between aeration and moisture uptake is not taken into account in the theoretical equations for moisture uptake.

scholarly journals Relationship between Soil and Plant Water Status in Wine Grapes under Various Water Deficit Regimes

2010 ◽  
Vol 20 (3) ◽  
pp. 585-593 ◽  
Author(s):  
Ana Centeno ◽  
Pilar Baeza ◽  
José Ramón Lissarrague
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Soil Water Potential ◽  
Threshold Value ◽  
Leaf Water ◽  
Wine Grape ◽  
Soil Matric Potential ◽  
Matric Potential

Limited water supply in arid and semiarid Mediterranean environments demands improving irrigation efficiency. The purpose of this study was to determine a functional relationship between soil water availability and wine grape (Vitis vinifera) water status to determine a threshold value of soil matric potential to trigger irrigation. Seasonal trends of soil water potential, leaf water potential, and stomatal conductance (gS) of ‘Tempranillo’ wine grape were determined in two deficit irrigation treatments replenishing 45% and 30% of the reference evapotranspiration, and in a third non-irrigated treatment during 2001 and 2002. Soil water potential was measured with granular matrix soil moisture sensors placed at 0.3 m (Ψ0.3), 0.6 m (Ψ0.6), and 1.2 m (Ψ1.2) depths. The sensors at 0.3 m depth quickly responded to irrigation by increasing Ψ0.3 levels. At the 0.6 m depth, Ψ0.6 progressively decreased, showing significant differences between T1 and the rest of the treatments, while no significant differences in Ψ1.2 were found. All relationships between profile soil matric potential and leaf water potential and gS were highly correlated. After integrating our data with previous studies, we suggest a whole profile soil water potential value of –0.12 MPa as threshold to trigger irrigation and avoid severe water stress during berry growth.

THE EFFECT OF SOIL WATER POTENTIAL, TEMPERATURE AND SEEDING DEPTH ON SEEDLING EMERGENCE OF WHEAT

1979 ◽  
Vol 59 (3) ◽  
pp. 259-264 ◽  
Author(s):  
R. DE JONG ◽  
K. F. BEST
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Minimum Temperature ◽  
Seedling Emergence ◽  
Potential Temperature ◽  
Soil Water Potential ◽  
Triticum Aestivum L ◽  
Planting Dates ◽  
Water Potentials ◽  
Soil Temperatures

Daily emergence counts were made on Canthatch wheat (Triticum aestivum L.) grown in five soil types, at four soil temperatures and three water potentials and planted at five different depths. Regardless of soil type, soil water potential or depth of planting, 50% emergence generally occurred within a week at 19.4 and 26.7 °C, and within 2 wk at 12.2 °C, but it took up to 6 wk at 5 °C. The heat sum required to attain 50% seedling emergence did not increase significantly with decreasing soil water potentials, but the minimum temperature for emergence dropped from 1.3 to 0.2 °C as the water potential decreased from −⅓ to −10 bar. It was suggested that the seedlings compensated for the increased water stress by lowering their minimum temperature requirements. Increasing the planting depth not only increased the heat requirement for emergence, but it also increased the variability of emergence, especially at low temperatures. Practical aspects concerning planting dates and depths were considered.

Seedling survivorship of temperate grassland perennials is remarkably resistant to projected changes in rainfall

2012 ◽  
Vol 60 (4) ◽  
pp. 328 ◽  
Author(s):  
Michael P. Perring ◽  
Mark J. Hovenden
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Seedling Emergence ◽  
Soil Water Potential ◽  
Annual Rainfall ◽  
Grassland Species ◽  
Seedling Survivorship ◽  
Water Recharge ◽  
Rainfall Reduction ◽  
Projected Changes

Recruitment is central to the maintenance of any plant population, particularly in disturbed or drought-prone environments. Recruitment relies on both seedling emergence and subsequent survival to establishment, processes susceptible to changes in soil water potential. Here, we use an existing relationship between seedling survivorship and soil water potential from the TasFACE global change impacts experiment situated in Tasmanian grassland, elucidate relationships between rainfall and soil water potential, and then simulate seedling survivorship responses to potential changes in both the amount and seasonal distribution of precipitation. Annual rainfall was a poor predictor of survivorship, suggesting the importance of seasonal and daily distribution of rain in determining establishment patterns. Modelled seedling survivorship was remarkably resistant to declines in rainfall, with a rainfall reduction of 40% reducing survivorship only by ~10%. Reducing spring rainfall only markedly reduced seedling survivorship when the rain removed was not added to winter rainfall. Our results show that soil water recharge during winter is critical to seedling survivorship of perennial species at the study site. Providing rainfall regimes allow recharge to occur, seedling survivorship of perennial grassland species may be maintained despite large reductions in rainfall, indicating that these grassland species may have an inherent capacity that limits the impacts of reductions in rainfall.

Soil and plant resistance effects on transpirational and leaf water responses by groundnut to soil water potential

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 51 ◽  
Author(s):  
RP Samui ◽  
S Kar
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Uptake ◽  
Plant Resistance ◽  
Sandy Loam ◽  
Soil Water Potential ◽  
Leaf Water ◽  
Arachis Hypogea ◽  
Water Potentials ◽  
Soil Water Conditions

The phasic and diurnal leaf water potential (�L) and transpirational responses to soil water potential by groundnut (Arachis hypogea L.) were investigated under controlled soil water conditions in a glasshouse. Three different soil water potentials (�s) in the tensiometric ranges were maintained in a lateritic sandy loam soil (Oxisol) during the seedling (S1), branching (S2) and peg formation (S3) stages of groundnut. Measured values of �s, �L rooting density, soil capillary conductivity and transpiration rate were used to calculate the soil and plant resistances to water uptake by the plant. The soil and plant resistances to water uptake by the groundnut plant increased appreciably as the soil water potential decreased from -0.11 to -0.70 bar. Plant resistance (Rp) was two to three orders of magnitude higher than soil resistance (Rs). Rs decreased with growth of the plant, whereas Rp increased, especially at -0.7 bar �s, Decreases in transpiration at �s lower than -0.33 bar were closely associated with the increases in the plant and soil resistances, and with lower leaf water potentials.

A Model for Predicting Common Cocklebur (Xanthium strumarium) Emergence in Soybean

Weed Science ◽  
2007 ◽  
Vol 55 (4) ◽  
pp. 341-345 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Marcos J. Oliveira
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Depth ◽  
Seedling Emergence ◽  
Soil Water Potential ◽  
Thermal Fluctuation ◽  
Parameter Estimates ◽  
Weibull Function ◽  
Base Temperature ◽  
Presence And Absence

The objective of this research was to develop a model to predict common cocklebur seedling emergence in spring tillage and no-spring-tillage systems in the presence and absence of a soybean canopy. A Weibull function was used to accumulate heat units (i.e., growing degree days) at a 2.5 cm soil depth on days when mean soil temperature, soil water potential, and soil thermal fluctuation were above established thresholds. The base temperature, soil water potential, and soil thermal fluctuation thresholds used for model development were 17 C, −100 kPa, and 7.5 C, respectively. A single function adequately described common cocklebur seedling emergence in the presence and absence of drill-seeded soybean from data combined over an artificial (2004) and natural seedbank (2005) (R2= 0.986). Model parameterization differed between the artificial and natural seedbank in the absence of spring tillage, but emergence was adequately described, regardless of soybean presence. Separate parameter estimates for the artificial and natural seedbanks were needed to adequately describe emergence in the system without spring tillage (R2= 0.975 to 0.984). The ability of the model to account for reduced emergence when soil moisture is limited or when daily thermal fluctuation requirements are not met could assist practitioners with assessments associated with field scouting for weeds as well as other management decisions.

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