The Effect of Mild Water Deficit on Basil Yield and Quality

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 517e-517
Author(s):  
Jennifer Warner ◽  
Albert H. Markhart
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Soil Water Potential ◽  
Leaf Tissue ◽  
Dry Weight ◽  
Secondary Compounds ◽  
Matric Potential ◽  
Taste Test ◽  
Sweet Basil ◽  
Flavor Components

Secondary compounds, essential oils, and flavor components of leaf tissue often increase in response to environmental stress. The objective of this study is to determine if a simple measure of soil matric potential could be used to generate mild plant water stress in sweet basil, which would improve the flavor components of the foliage. Sweet basil was grown in Universal Soil Mix with adequate water and fertilization in greenhouses supplied with 18 h of high-pressure sodium supplemental lighting until the third pair of leaves was fully expanded. Aquaprobe matric potential sensors were installed in the center of the pot and soil matric potentials recorded daily. Water was withheld from stressed plants until the soil water potential reached –4 bars. Treatments consisted of one or two stress cycles. Plants were harvested 24 h after rewatering and fresh and dry weights determined. The youngest two fully expanded leaves were placed in zip log bags and used in a taste test. The two water stress treatments decreased leaf fresh weight by 10% and 16%, respectively, decreased total plant dry weight by 6% and 10%, respectively, and had moderate effect on flavor intensity as rated by our taste test panel. The substantial decrease in yield suggests that –4 bars was too severe a stress to be used commercially. The Aquaprobe sensor was an easy to use economical way to monitor soil water and could be useful in regulating watering in a greenhouse environment.

Adaptation to Water Stress of the Leaf Water Relations of Four Tropical Forage Species

1980 ◽  
Vol 7 (2) ◽  
pp. 207 ◽  
Author(s):  
JR Wilson ◽  
MM Ludlow ◽  
MJ Fisher ◽  
E Schulze
Keyword(s):  
Water Stress ◽  
Water Content ◽  
Water Relations ◽  
Bound Water ◽  
Leaf Tissue ◽  
Dry Weight ◽  
Panicum Maximum ◽  
Soil Drying ◽  
Buffel Grass ◽  
Heteropogon Contortus

Three tropical grasses, green panic (Panicum maximum var, trichoglume), spear grass (Heteropogon contortus) and buffel grass (Cenchrus ciliaris) and the tropical legume siratro (Macroptilium atropurpureum), were grown in plots in a semi-arid field environment. The water relations characteristics of leaves from plants subjected to a soil drying cycle were compared with those of unstressed leaves from plants in irrigated plots. Minimum water potentials attained in the stressed leaves were c. -44, - 38, - 33 and - 13 bar for the four species, respectively. The grass leaves adjusted osmotically to water stress, apparently through accumulation of solutes, so that there was a decrease in osmotic potential at full turgor (Ψπ100) of 5.5, 3.9 and 7.1 bar, and in water potential at zero turgor (Ψ0) of 8.6, 6.5 and 8.6 bar for green panic, spear grass and buffel respectively. Water stress appeared to increase slightly the proportion of bound water (B) and the bulk modulus of elasticity (ε) of the grass leaves, but it did not alter the relative water content at zero turgor (RWC0) or the ratio of turgid water content to dry weight of the tissue. The Ψπ100 and Ψ0 of stressed siratro leaves decreased by 2.5-4 bar and 3-5 bar respectively when subjected to soil drying cycles. These changes could be explained by the marked decrease in the ratio of turgid water content to dry weight of the leaf tissue rather than by accumulation of solutes. The values of RWC0 and ε for siratro leaves were not altered by stress but, in contrast to the grasses, B was apparently decreased although the data exhibited high variability. Adjustments in Ψπ100 and Ψ0 of stressed leaves of buffel grass and siratro were largely lost within 10 days of rewatering.

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.

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.

scholarly journals Canopy temperature and heat stress are increased by compound high air temperature and water stress and reduced by irrigation – a modeling analysis

2021 ◽  
Vol 25 (3) ◽  
pp. 1411-1423 ◽  
Author(s):  
Xiangyu Luan ◽  
Giulia Vico
Keyword(s):  
Heat Stress ◽  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Air Temperature ◽  
Water Availability ◽  
Plant Traits ◽  
Soil Water Potential ◽  
Canopy Temperature ◽  
Threshold Temperature

Abstract. Crop yield is reduced by heat and water stress and even more when these conditions co-occur. Yet, compound effects of air temperature and water availability on crop heat stress are poorly quantified. Existing crop models, by relying at least partially on empirical functions, cannot account for the feedbacks of plant traits and response to heat and water stress on canopy temperature. We developed a fully mechanistic model, coupling crop energy and water balances, to determine canopy temperature as a function of plant traits, stochastic environmental conditions, and irrigation applications. While general, the model was parameterized for wheat. Canopy temperature largely followed air temperature under well-watered conditions. But, when soil water potential was more negative than −0.14 MPa, further reductions in soil water availability led to a rapid rise in canopy temperature – up to 10 ∘C warmer than air at soil water potential of −0.62 MPa. More intermittent precipitation led to higher canopy temperatures and longer periods of potentially damaging crop canopy temperatures. Irrigation applications aimed at keeping crops under well-watered conditions could reduce canopy temperature but in most cases were unable to maintain it below the threshold temperature for potential heat damage; the benefits of irrigation in terms of reduction of canopy temperature decreased as average air temperature increased. Hence, irrigation is only a partial solution to adapt to warmer and drier climates.

scholarly journals Onion Response to Water Stress

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 837D-837
Author(s):  
Clinton C. Shock ◽  
Erik B.G. Feibert ◽  
Lamont D. Saunders
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Marketable Yield ◽  
Water Deficits ◽  
Yield And Quality ◽  
Highly Sensitive ◽  
Granular Matrix ◽  
Response To Water

Six soil water potential irrigation criteria (–12.5 to –100 kPa) were examined to determine levels for maximum onion yield and quality. Soil water potential at 0.2-m depth was measured by tensiometers and granular matrix sensors (Watermark Model 20055, Irrometer Co., Riverside, Calif.). Onions are highly sensitive to small soil water deficits. The crop needs frequent irrigations to maintain small negative soil water potentials for maximum yields. In each of 3 years, yield and bulb size increased with wetter treatments. In 1994, a relatively warm year, onion yield and bulb size were maximized at –12.5 kPa. In 1993, a relatively cool year, onion marketable yield peaked at –37.5 kPa due to a significant increase in rot during storage following the wetter treatments.

Effects of Temperature, Soil Water Status and Depth of Planting on Germination and Emergence of Maize (Zea Mays) Adapted to Semi-Arid Eastern Kenya

1993 ◽  
Vol 29 (3) ◽  
pp. 351-364 ◽  
Author(s):  
J. K. Itabari ◽  
P. J. Gregory ◽  
R. K. Jones
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Status ◽  
Soil Water Potential ◽  
Thermal Time ◽  
Controlled Environment ◽  
Base Temperature ◽  
Matric Potential ◽  
Effects Of Temperature ◽  
Time Required

SUMMARYThe effects of temperature and soil water potential on maize germination were investigated in controlled environment conditions and the effects of depth of planting and a mulch on maize emergence were studied in a field experiment in eastern Kenya. The rate of germination increased to an optimum temperature of 33.6°C above a base temperature of 6.1°C and decreased above the optimum to zero germination at 42.9°C. The thermal time for median germination increased from 51.5°Cd to 56.4°Cd as soil matric potential decreased from -5 to -40 kPa. Soil water content, depth of planting, and their interaction had significant (P < 0.001) effects on final germination and emergence but mulch, or any interactions involving mulch, had no such effects. Increasing depth of planting by 1 cm increased the thermal time required for emergence by 2.8°Cd, and decreasing water content by 1% increased the thermal time required for emergence by 3.2°Cd.Germinación y emergencia del maíz

Location of hydraulic resistance in the soil–plant pathway in seedlings of Pinussylvestris L. grown in peat

1986 ◽  
Vol 16 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Göran Örlander ◽  
Karin Due
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Dry Weight ◽  
Membrane System ◽  
Point Of View ◽  
Plant Water ◽  
Water Conductance ◽  
Dry Conditions ◽  
Total Dry Weight

Seedlings of Pinussylvestris L. were grown in three different soil media: 100% peat, 40% silt–60% peat, and 60% silt–40% peat. The percentages refer to total dry weight. Needle conductance, needle water potential, and plant water conductance were measured at different levels of soil water potentials controlled with a semipermeable membrane system. Seedlings grown in the 60:40 silt–peat mixture had a plant water conductance at a soil water potential of −0.1 MPa 3 times that of seedlings grown in pure peat. In an experiment where the roots were dipped in a silt slurry before planting, it was found that the plant water conductance at low soil water potential (−0.1 MPa) increased more than 2 times compared with undipped controls. We concluded that an important resistance to water flow in the soil–plant pathway was located in the soil outside the roots and probably was the most important resistance in the root–soil interface. The use of low humified peat as a growth medium is open to discussion from a silvicultural point of view because of its hydraulic properties under dry conditions.

Water-stress tolerance of black and eastern cottonwood clones and four hybrid progeny. I. Growth, water relations, and gas exchange

1994 ◽  
Vol 24 (2) ◽  
pp. 364-371 ◽  
Author(s):  
T.J. Tschaplinski ◽  
G.A. Tuskan ◽  
C.A. Gunderson
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Stress Tolerance ◽  
Soil Water ◽  
Osmotic Adjustment ◽  
Soil Water Potential ◽  
Hybrid Progeny ◽  
Black Cottonwood ◽  
Eastern Cottonwood ◽  
Water Stress Tolerance

Water-stress tolerance of six clones in a pedigree consisting of black cottonwood (Populustrichocarpa Torr. & Gray, female) and eastern cottonwood (Populusdeltoides Bartr., male) parental clones and four hybrid progeny was investigated. Trees were grown outdoors in pots; well-watered trees were kept moist (soil water potential greater than −0.03 MPa), and stressed trees (soil water potential less than −2.0 MPa) were subjected to repeated cyclical stress of 1 or 2 days duration over the 14-week study. Male P. deltoides and the male clone 242 displayed the greatest degree of stress tolerance, as evidenced by greater osmotic adjustment at saturation (0.25 MPa) and maintenance of relative growth rate of the main stem under water stress at 100 and 69% of that of well-watered trees, respectively, compared with reductions to 50–58% for the other hybrid clones. However, differences in total plant dry weight under water stress were less obvious, with female clones allocating more carbon to branch production under well-watered conditions, which was further increased under water stress. Three of the four hybrids displayed some degree of osmotic adjustment at saturation after bud set, which was likely conferred by male P. deltoides. Screening clones of Populus for drought tolerance should take into account the segregating tendency of hybrids to allocate carbon to lateral meristems under stress.

Water relations of winter wheat: 3. Components of leaf water potential and the soil-plant water potential gradient

1983 ◽  
Vol 100 (3) ◽  
pp. 581-589 ◽  
Author(s):  
J. S. Wallace ◽  
J. A. Clark ◽  
M. McGowan
Keyword(s):  
Water Stress ◽  
Winter Wheat ◽  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Potential Gradient ◽  
Potential Drop ◽  
Root Surface ◽  
Total Water ◽  
Leaf Osmotic Potential

SUMMARYDiurnal and seasonal changes in the total, osmotic and turgor potentials of winter wheat leaves are compared in two seasons of mild and severe soil water stress. Gradients of total water potential in the soil-plant system are also presented. In both seasons the total water potential of the leaves decreased in parallel with the soil water potential, concurrently leaf osmotic potential also decreased sufficiently to maintain positive leaf turgor potential. Eventually, under severe water stress, soil water potential approached –1·5 MPa and leaf turgor potential tended to zero during the middle of the day.The potential drop across the soil-root system was twice that along the stem. Estimates of the water potential at the root surface varied diurnally and were often lower than the bulk soil water potential. In dry soil plants were unable to equilibrate with the soil water potential overnight. These results are consistent with the existence of significant resistance to water flow across the rhizosphere.

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