A Technique for Determining Resistance to Mass Transfer Through the Boundary Layers of Plants with Complex Structure

Landsberg, J. J.; Ludlow, M. M.

doi:10.2307/2401619

Cited by 47 publications

(24 citation statements)

References 7 publications

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“…The air of the cuvette was well stirred giving a boundary layer conductance to CO2 of 4.6 mol m 2 s -1 for a shoot of Norway spruce. The boundary-layer conductance was determined by the plaster cast method of Landsberg and Ludlow (1970). Air temperature in the cuvette was 18.3 _+ 0.5 ~ C and needle temperature was 18.9___0.7~ Air temperature was measured using a Pt-100 sensor and needle temperature by pressing a thermocouple (type K, Ni: Cr/Ni, Tradonor, Stockholm) against the lower side of the needles.…”

Section: Methodsmentioning

confidence: 99%

The influence of ozone on the stomatal and non-stomatal limitation of photosynthesis in Norway spruce, Picea abies (L.) Karst, exposed to soil moisture deficit

Wallin

Skärby

1992

Trees

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Summary. Norway spruce, Picea abies (L.) Karst., was exposed to charcoal-filtered air (CF) and non-filtered air + ozone (NF+) and periods of soil moisture deficit from 1985 to 1988 in open-top chambers. Net photosynthesis, stomatal conductance, needle water potential and various shoot properties were measured on 1-year-old shoots during a period of soil moisture deficit. The gas exchange was measured at saturating photosynthetic photon flux density and across a range of CO2 concentrations. The soil moisture deficit induced a mild drought stress in the plants, expressed by a pre-dawn needle water potential of approximately -0.9 MPa and a substantial reduction in net photosynthesis and gas phase conductance. In the CF treatment, intercellular CO2 concentration was reduced, but was unaffected in the NF+ treatment. Furthermore, net photosynthesis declined more in response to the soil moisture deficit in the NF+ treatment than in the CF treatment. This is suggested to be attributed to the carboxylation efficiency at the operating point, which was decreased by 47% and 64% in shoots from the CF and the NF+ treatments, respectively. Stomatal limitation of net photosynthesis was increased by drought by 24-45% in the CF treatment, while it was unaffected in the NF+ treatment. Thus, our results imply that the coupling between the stomatal conductance and the photosynthetic rate was changed and that the marginal cost of water per given amount of carbon gain will increase in trees exposed to ozone, during periods of drought.

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Section: Methodsmentioning

confidence: 99%

The influence of ozone on the stomatal and non-stomatal limitation of photosynthesis in Norway spruce, Picea abies (L.) Karst, exposed to soil moisture deficit

Wallin

Skärby

1992

Trees

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“…If this is the case, then equations applicable to a totally wet canopy become applicable when the fraction of the surface covered in water, the 'Wetness Factor', W, is large enough to allow the Intrinsic Surface Resistance to water-vapour flux, RI" (Shuttleworth, 1975), to 'short-cut' the stomata1 resistance and reduce the resulting 'internal' part of the surface resistance for each element to such an extent as to make it negligible compared to the 'boundary-layer' part. Assuming the theoretical estimate RI"-0.05 s m-r given by Shuttleworth (1975), this might occur when the element is only a few per cent wet, even for elements with very little 'boundary-layer' resistance (20 s m-') such as Sitka spruce (Landsberg and Ludlow, 1970).…”

Section: The Evaporation/condensation Exchange Process (A) a Simplifimentioning

confidence: 99%

“…Figure A2(a) illustrates the variation of the weighting factor [x3N] as a function of x, for the extreme values of n and a (Equation AlO) used in the calculations, while Figure A2(b) shows the value of impaction efficiency (at a wind speed of 1 m s-r) plotted as a function of drop-size for cylinder 1 mm in diameter. This value was chosen as typical of the needle diameter for Sitka spruce (Landsberg and Ludlow, 1970) and Scats pine (Roberts, 1976). The efficiency was deduced from the function illustrated in Figure Al integration of Equation A6) for cylindrical vegetative elements 1 mm in diameter.…”

Section: (D) Drop-size Distributionsmentioning

confidence: 99%

The exchange of wind-driven fog and mist between vegetation and the atmosphere

Shuttleworth¹

1977

Boundary-Layer Meteorol

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This paper presents a one-dimensional theoretical description of the exchange of water between wind-driven fog and natural vegetation for two processes, the first involving direct capture of the fog droplets and the second involving exchange by the evaporation/condensation process. It is shown that the 'direct capture' mechanism is formally similar to other atmosphere/vegetation exchange processes, being under the control of a 'surface' and an 'aerodynamic' resistance. A theoretical estimate is made of the magnitude and variation of this surface resistance for an idealized coniferous canopy, and consideration given to the relative importance of the two processes for both 'short' and 'tall' vegetation. The analysis is used to illuminate previous observations of the fog interception phenomenon, and as a basis for recommendations on future work in this field.

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“…Previous investigators have measured aerodynamic resistances to heat transfer for coniferous shoots (10,11) and Jarvis et al (7) converted their values to equivalent R' values. These R' values ranged from 2.8 to 15.8 s m-1 for various orientations to wind flows of from 35 to 520 cm s-', respectively.…”

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confidence: 99%

Importance of Aerodynamic Resistance to Water Use Efficiency in Three Conifers under Field Conditions

Smith

1980

Plant Physiol.

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The quantitative importance of aerodynamic resistance to H20 vapor and CO2 exchange was determined for shoots from saplings of three conifers (Abiks kiocarpa [Hooki Nutt., Pinus conforta Dougl., Junipers commwus L.) under natural conditions in the field. A combination of relatively low stomatal resistances (< 300 seconds per centimeter) and low wind speeds (< 30 centimeters per second) led to substantial contributions of the aerodynamic resistance (R",) Several investigations have examined the magnitude of the aerodynamic, or boundary air layer, resistance to heat and mass transfer for a variety of leaves, or leaf replicas (3, 8-12, 14, 15, 18, 19). Only a few of these studies have attempted to estimate the quantitative influence of this resistance on transpiration and photosynthesis under field conditions (13,14,16). No attempt has been made to estimate the quantitative importance of this resistance based on simultaneous measurements of the aerodynamic properties and gas exchange rates of leaves or shoots under natural field conditions. The purpose of the present study was 1978). Aerodynamic resistances to water vapor transfer were determined for detached shoots coated with a thin layer of gypsum as described in Landsberg and Ludlow (10) for complex plant structures. This process was modified slightly by the addition of a polyethylene potometer tube filled with distilled H20 to prolong the measurement interval to several hours. For all experimental shoots, the weight lost per unit time was divided by the total needle area to give transpirational flux. The stomatal resistance (R') and surface resistance to water vapor diffusion of the gypsum-coated shoots were measured with a diffusion resistance porometer (Lambda Instruments model LI-85) throughout the experiment. This surface resistance never exceeded a value of 64 s m-l (conductance > 0.016 m s-1) for all experimental periods.Total leaf area was determined gravimetrically from correlations of dry weight versus area for individual needles. Total needle areas for experimental shoots ranged from 164 to 418 cm2 for shoots with main axes that were from 24 to 38 cm in length, respectively. Detached experimental shoots were placed at locations immediately adjacent to the sampled plant, or in their simulated natural canopy positions. Wind flow was measured at the midpoint of the shoot length approximately 10 cm above the shoot stem. Turbulence intensity (TI) was calculated as described by Sutton (22

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A Technique for Determining Resistance to Mass Transfer Through the Boundary Layers of Plants with Complex Structure

Cited by 47 publications

References 7 publications

The influence of ozone on the stomatal and non-stomatal limitation of photosynthesis in Norway spruce, Picea abies (L.) Karst, exposed to soil moisture deficit

The influence of ozone on the stomatal and non-stomatal limitation of photosynthesis in Norway spruce, Picea abies (L.) Karst, exposed to soil moisture deficit

The exchange of wind-driven fog and mist between vegetation and the atmosphere

Importance of Aerodynamic Resistance to Water Use Efficiency in Three Conifers under Field Conditions

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