A simulation of water relations of white oak based on soil moisture and atmospheric evaporative demand

1977 ◽  
Vol 7 (2) ◽  
pp. 400-409 ◽  
Author(s):  
D. R. Thompson ◽  
T. M. Hinckley
Keyword(s):  
Soil Moisture ◽  
Surface Resistance ◽  
Vapor Pressure Deficit ◽  
Leaf Surface ◽  
White Oak ◽  
Pressure Potential ◽  
Evaporative Demand ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Predicted Values

A model was described which simulated xylem pressure potential and leaf surface resistance for a white oak (Quercusalba L.) tree and several saplings in central Missouri. The simulation was accomplished using a deterministic approach and was applicable from after leaf maturation in the spring to leaf senescence in the fall. Soil moisture content, vapor pressure deficit, and solar radiation were the required driving variables. The Ohm's law analogy describing water potentials and fluxes in the soil–plant–atmospheric continuum served as the basis for the model. The model was tested with data not used in the original parameter estimation, and very close agreement between observed and predicted values was found. The patterns of xylem pressure potential and leaf surface resistance obtained from simulation runs imply that white oak has a significant amount of stress tolerance and an ability to avoid severe dehydration.

Effect of Mid-day Shading on Stem Diameter, Xylem Pressure Potential, Leaf Surface Resistance, and Net Assimilation Rate in a White Oak Sapling

1974 ◽  
Vol 4 (3) ◽  
pp. 296-300 ◽  
Author(s):  
T. M. Hinckley ◽  
J. L. Chambers ◽  
D. N. Bruckerhoff ◽  
J. E. Roberts ◽  
J. Turner
Keyword(s):  
Surface Resistance ◽  
Leaf Surface ◽  
Stem Diameter ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
White Oak ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Net Assimilation

The diurnal relationship between xylem pressure potential and stem diameter in white oak (Quercusalba L.) resulted in a hysteresis loop on clear days where, for a given level of xylem pressure potential, the stem was thinner upon rehydration than during dehydration. Cloudy days complicated this pattern by forming a loop within the main loop. This additional loop was caused by the same factor which caused the main loop, the delayed reaction or lag between changes in stem diameter and xylem pressure potential. Both net assimilation rate and leaf surface resistance were closely linked and responded rapidly to changes in radiation. Hydroactive increases in leaf surface resistance were observed as xylem pressure potential decreased below −23 bars. A discussion of the relationship between stem diameter, radiation, leaf surface resistance, and xylem pressure potential is presented.

The effects of drought on water relations and stem shrinkage of Quercus alba

1975 ◽  
Vol 53 (1) ◽  
pp. 62-72 ◽  
Author(s):  
Thomas M. Hinckley ◽  
David N. Bruckerhoff
Keyword(s):  
Soil Moisture ◽  
Surface Resistance ◽  
Leaf Surface ◽  
Stomatal Closure ◽  
Quercus Alba ◽  
Plant Water ◽  
White Oak ◽  
Water Deficits ◽  
Xylem Pressure Potential ◽  
Diurnal Fluctuations

Stem circumference, xylem pressure potential (P), and leaf surface resistance were measured in a dominant forest-grown white oak (Quercus alba L.) tree from the beginning of, through the development of, and to recovery from a major drought in mid-Missouri. Continuous recording of several environmental variables and periodic measurements of soil moisture were made in coordination with the above plant variables. As base P(P measured just before sunrise) and soil moisture decreased, net day-to-day and even week-to-week stem shrinkage was observed. Periodic thunderstorms alleviated soil and plant water deficits and stem circumference recovered. Excellent relationships were noted between soil moisture in the upper 30 cm of a 107-cm profile and either base P or stem circumference.Four clear and 2 cloudy days with rain are presented to illustrate diurnal patterns in the aforementioned variables. The generalized pattern of diurnal fluctuations in stem circumference consisted of early morning shrinkage, which continued to a 1500- to 1700-h. (true solar time) minimum, and subsequent recovery. Hysteresis loops resulted when stem circumference was plotted against P. Maximum diurnal fluctuations in stem circumference were greatest when soil moisture had been depleted slightly below field capacity. Further depletion led to lower values of P, stomatal closure, restricted plant water loss, and reduced stem shrinkage. The relationship between flux (vapor pressure deficit – leaf surface resistance) and P is also described and it provided a possible means of modeling P in plants. The possible role of the stem reservoir in augmenting foliar water deficits is presented and discussed.

The influence of a severe drought on net photosynthesis of white oak (Quercus alba)

1981 ◽  
Vol 59 (3) ◽  
pp. 335-341 ◽  
Author(s):  
Phillip M. Dougherty ◽  
Thomas M. Hinckley
Keyword(s):  
Soil Moisture ◽  
Forest Type ◽  
Soil Water Potential ◽  
Net Photosynthesis ◽  
Daily Maximum ◽  
Severe Drought ◽  
White Oak ◽  
Pressure Potential ◽  
Evaporative Demand ◽  
Xylem Pressure Potential

A prolonged and intense drought during the summer of 1976 caused soil water potential in the upper 45 cm of the soil profile to decrease below −2.5 MPa. Predawn xylem pressure potential (P) frequently was less than −1.8 MPa. Under conditions of high soil moisture, net photosynthesis averaged more than 8.0 mg CO2∙dm−2∙h−1 between 0500 and 1800 hours, and maximum rates of net photosynthesis were above 14.0 mg CO2∙dm−2∙h−1. Average and daily maximum net photosynthesis decreased to less than 1.0 and 8.0 mg CO2∙dm−2∙h−1, respectively, during the peak of the drought. Maximum rates of net photosynthesis observed under controlled light and temperature conditions remained above or near 14.0 mg CO2∙dm−2∙h−1 even when predawn P equalled −1.83 MPa. Net photosynthesis seldom decreased below zero if quantum flux densities were greater than the compensation point during this period of record low soil moisture. Environmental conditions, such as fog and clouds, which reduced leaf temperatures and atmospheric evaporative demand, increased net photosynthesis although predawn P was less than −1.8 MPa. During cloudy days, rates of net photosynthesis were within 80% of those observed under ideal soil moisture conditions. The photosynthetic characteristics of white oak noted during this drought are coupled with other physiological traits of white oak to explain its relative success in the oak–hickory forest type.

Water deficits and root growth of ectomycorrhizal white oak seedlings

1980 ◽  
Vol 10 (4) ◽  
pp. 545-548 ◽  
Author(s):  
R. K. Dixon ◽  
G. M. Wright ◽  
G. T. Behrns ◽  
R. O. Teskey ◽  
T. M. Hinckley
Keyword(s):  
Leaf Surface ◽  
Soil Water Potential ◽  
Leaf Conductance ◽  
Silt Loam ◽  
White Oak ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Leaf Surface Area ◽  
Loam Soil

White oak (Quercusalba L.) seedlings grown in a silt loam soil inoculated with Pisolithustinctorius (Pers.) Coker and Couch exhibited 80% ectomycorrhizal development after a 6-month establishment period whereas the noninoculated controls exhibited less than 5%.When water was withheld and soil water potential decreased as the soil dried, xylem pressure potential and leaf conductance of both the inoculated and noninoculated seedlings declined gradually. At the peak of the drying cycle, the inoculated seedlings exhibited mean prelight and midlight xylem pressure potential values which were 0.2 MPa and 0.15 MPa, respectively, more negative than the noninoculated seedlings. Although the inoculated seedlings had a mean leaf surface area 1.5 times larger than that of the noninoculated seedlings, there were no significant differences in leaf conductance at the peak of the dehydration cycle. Mean rates of root elongation were greater among the inoculated seedlings during the drying cycle. Following reirrigation of the soil, the inoculated seedlings yielded significantly less negative values of prelight and midlight xylem pressure potential and greater leaf conductance when compared to the noninoculated seedlings.

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.

Water relations of white spruce (Piceaglauca (Moench) Voss) at tree line in north central Alaska

1985 ◽  
Vol 15 (6) ◽  
pp. 1080-1087 ◽  
Author(s):  
Guillermo H. Goldstein ◽  
Linda B. Brubaker ◽  
Thomas M. Hinckley
Keyword(s):  
Water Flow ◽  
Near Field ◽  
White Spruce ◽  
Boundary Line ◽  
Tree Line ◽  
Pressure Potential ◽  
Evaporative Demand ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Northern Alaska

Factors affecting xylem pressure potential and stomatal behavior during the growing season were studied on white spruce (Piceaglauca (Moench) Voss) at tree line in the central Brooks Range of northern Alaska. Leaf conductance and xylem pressure potentials were low during days of moderate and high evaporative demand, even though soil moisture was near field capacity. Boundary line diagrams, regression analysis, and laboratory experiments indicate that stomata are sensitive to changes in vapor pressure deficit and xylem pressure potential. A correlation between resistance to water flow through the tree and soil temperature suggests that soil temperatures less than 9 °C are associated with increased resistance to water flow and may partially explain the position of white spruce tree line in northern Alaska.

Critical Period of Weed Interference in Transplanted Tomatoes (Lycopersicon esculentum): Growth Analysis

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 476-481 ◽  
Author(s):  
Susan E. Weaver ◽  
Chin S. Tan
Keyword(s):  
Lycopersicon Esculentum ◽  
Critical Period ◽  
Growth Analysis ◽  
Canopy Temperature ◽  
Dry Weight ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Fruit Number ◽  
Weed Interference ◽  
Xylem Pressure Potential

The critical period of weed interference in transplanted tomatoes (Lycopersicon esculentumMill. 'Springset’) was from 28 to 35 days after transplanting. A single weeding during this period was sufficient to prevent yield reductions. A growth analysis revealed that significant differences in plant dry weight and fruit number between tomatoes from weed-free and weed-infested plots were not apparent until 56 to 70 days after transplanting. The shorter the initial weed-free period, or the longer weeds were allowed to remain in the plots before removal, the earlier reductions in tomato dry weight and fruit number appeared. Weed interference was due primarily to shading rather than water stress. Tomatoes from weed-infested plots had significantly lower stomatal conductances than those from weed-free plots, but did not differ in xylem-pressure potential or in canopy temperature. If tomatoes were kept weed-free for more than 28 days, or when weeds were present for less than 28 days after transplanting, stomatal conductances were not significantly reduced.

scholarly journals Environmental effects on efficacy of herbicides for postemergence goosegrass (Eleusine indica) control

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Avat Shekoofa ◽  
James T. Brosnan ◽  
Jose J. Vargas ◽  
Daniel P. Tuck ◽  
Matthew T. Elmore
Keyword(s):  
Soil Moisture ◽  
Environmental Effects ◽  
Vapor Pressure Deficit ◽  
Sandy Soils ◽  
Silica Sand ◽  
Soil Drying ◽  
Silt Loam ◽  
Evaporative Demand ◽  
Eleusine Indica ◽  
High Soil Moisture

AbstractExperiments were conducted to understand environmental effects on efficacy of herbicides used to control goosegrass (Eleusine indica L. Gaertn.). Herbicides were applied to goosegrass maintained at soil moisture contents (VMC) of < 12%, 12 to 20%, or > 20%. Herbicides included fenoxaprop-p-ethyl (140 g ha−1), topramezone (25 g ha−1), foramsulfuron (44 g ha−1), 2,4-D + dicamba + MCPP + carfentrazone (860 + 80 + 270 + 28 g ha−1), and thiencarbazone-methyl + foramsulfuron + halosulfuron-methyl (22 + 45 + 69 g ha−1). Goosegrass control increased as VMC increased. Vapor pressure deficit (VPD) and air temperature were manipulated to determine effects of evaporative demand on foramsulfuron. Effects of soil drying were also studied following foramsulfuron application. Reductions in transpiration rate (TR) and leaf area were greatest with foramsulfuron applications to goosegrass in silt-loam under high evaporative demand (3 kPa VPD, 38 °C). Foramsulfuron had no effect on goosegrass in silica-sand regardless of evaporative demand. TR dropped to 0.2 mmh−1 within eight days after application to goosegrass in silt-loam compared to 18 days in silica-sand. Overall, foramsulfuron efficacy on goosegrass was maximized under conditions of high soil moisture and evaporative demand, and may be reduced in sandy soils that hold less water.

Comparative Studies in Selected Species of Eucalyptus Used in Rehabilitation of the Northern Jarrah Forest, Western Australia. I. Patterns of Xylem Pressure Potential and Diffusive Resistance of Leaves

1984 ◽  
Vol 32 (4) ◽  
pp. 367 ◽  
Author(s):  
IJ Colquhoun ◽  
RW Ridge ◽  
DT Bell ◽  
WA Loneragan ◽  
J Kuo
Keyword(s):  
Western Australia ◽  
Water Loss ◽  
Seasonal Patterns ◽  
Pressure Potential ◽  
Jarrah Forest ◽  
Eucalyptus Marginata ◽  
Xylem Pressure ◽  
Diffusive Resistance ◽  
Xylem Pressure Potential ◽  
The Impact

Land use which reduces tree canopy density and the impact of Phytophthora cinnamomi are believed to be altering the hydrological balance of parts of the northern jarrah forest, Western Australia. In the drier eastern zones of the forest, replacement plant communities must maintain the soil-salt-water balance to prevent significant increases in salinization of streams in water supply catchments. Daily and seasonal patterns of the diffusive resistance of leaves and xylem pressure potential were determined for the major natural dominant of the region, Eucalyptus marginata, and five other species of Eucalyptus used in rehabilitation. Three types of daily and seasonal patterns were observed. E. marginata and E. calophylla exhibited little stomatal control of water loss, and leaf resistances remained low throughout the study period (type 1). E. maculata, E. resinifera and E. saligna exhibited marked stomatal regulation during summer days when xylem pressure potentials fell below -2.O MPa (type 2). E. wandoo (type 3) also controlled water loss but developed xylem pressure potentials far lower than all other species tested (<-3.0 MPa). Although none of the species tested replicated the summer stomatal resistance and xylem pressure potential patterns of E. marginata, it is suggested that total annual water use should be examined before selecting the most appropriate species to rehabilitate disturbed sites in the eastern zones of the northern jarrah forest region.

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