A Null-Balance Diffusion Porometer Suitable for Use with Leaves of Many Shapes

Beardsell, Michael F.; Jarvis, P. G.; Davidson, Brian

doi:10.2307/2401897

Cited by 116 publications

(40 citation statements)

References 15 publications

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“…Diurnal transpiration for the three species was determined from stomatal conductance measured approximately monthly using a Li-Cor 1600 null-balance porometer (Beardsell et al, 1972). A polycarbonate chamber attachment was used to enclose small branch segments 4-6 cm in length for sampling.…”

Section: Tlf I Determinationmentioning

confidence: 99%

Transpiration coefficients for three Great Basin shrubs

Steinwand

Harrington

Groeneveld³

2001

Journal of Arid Environments

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Section: Tlf I Determinationmentioning

confidence: 99%

Transpiration coefficients for three Great Basin shrubs

Steinwand

Harrington

Groeneveld³

2001

Journal of Arid Environments

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“…Equations such as *1= * -qR-pgh (1) where I' and I8 are leaf and soil water potential, q is total water flow through the plant, R is total plant resistance, and pgh is the hydrostatic gradient, are useful for dealing with small plants with very little capacitance. They are inadequate for larger trees, because it is not possible to measure q, and prediction of q requires k1 which in a process model requires '1.…”

mentioning

confidence: 99%

Soil Temperature Influences on Root Resistance of Pinus contorta Seedlings

Running¹,

Reid²

1980

Plant Physiol.

106

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The influence of low temperature in the root zone on water uptake in lodgepole pine (Pinus contorta Dougl ex Loud.) was studied under laboratory conditions. To remove soil hydraulic influences, two-year-old seedlngs were transferred to solution cultures and maintained in temperature controlled water baths. Short term measurements of leaf conductance, leaf water potential and tritiated water movement were taken at root temperatures from 22 C down to 0 C. Root resistance was calculated to be 67% of total plant resistance at 7 C and 93% at 0 C. In adtion an Arrhenius break was found in a plant resistance versus temperature plot, suggesting a significant change with temperature in the membrane pathway in the root water uptake system. water potential (4') and/or soil temperature, disregarding morphological development such as degree ofsuberization, and factors such as aeration and root disease. This paper will concentrate on the effect of temperature on root resistance to water transport in the context of whole plant water relations.The primary objective was to develop a functional relation between soil temperature and root resistance for Pinus contorta that was compatible with process modeling efforts of tree water movement (23). To isolate root resistance as the component of plant resistance responding to soil temperature, these water uptake experiments were performed on seedlings in aerated solution culture so there could be no complications caused by soil hydraulic conductivity. In addition, underwater root excision was used to determine the proportion of total water potential drop generated at the root surface. Finally, by comparing seedlings from a greenhouse and a 2 C cold room, influences of preconditioning on root resistance were examined.There has been wide documentation of the influence of V12 on stomatal or k,. Water-limited western conifers exhibit significant stomatal control triggered by *, (8). Consequently, recent efforts to model water movement and transpiration in trees have spent considerable effort in developing functions relating '1 to k, (14, 23).However, a useful process model oftree water movement cannot rely on collected *P data, but must be able to predict P1 over a wide range of conditions. Equations such as *1= * -qR-pgh (1) where I' and I8 are leaf and soil water potential, q is total water flow through the plant, R is total plant resistance, and pgh is the hydrostatic gradient, are useful for dealing with small plants with very little capacitance. They are inadequate for larger trees, because it is not possible to measure q, and prediction of q requires k1 which in a process model requires '1. Also, sapwood capacitance produces hysteresis in the '1 versus q relation (24). Predictions of I1 must be accomplished by defining the individual factors that produce it, and coupling these in the process model. In equation 1, R, total plant resistance, is one factor that must be separated. Much work has been done measuring stomatal resistance (8).Considerably less work has been reported o...

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“…Actuellement, (HEATH & RUSSEL, 1951 ;RASCHKE, 1965 ;WEATHERLEY, 1965 ; V AN B AVEL et al, 1965 ;K ANEMASU et al, 1969 ;S TILES , 1970 ; MO NTEITH ôt! B ULL , 1970 ;BEARDSELL et al, 1972 ;PARKINSON & LEGG, 1972 ;CAMPBELL, 1975 …”

Section: Introductionunclassified

Etude et amélioration de la fiabilité d'un poromètre à diffusion utilisé en milieu naturel

Katerji¹,

Oulid-Aïssa²

1983

Agronomie

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A Null-Balance Diffusion Porometer Suitable for Use with Leaves of Many Shapes

Cited by 116 publications

References 15 publications

Transpiration coefficients for three Great Basin shrubs

Transpiration coefficients for three Great Basin shrubs

Soil Temperature Influences on Root Resistance of Pinus contorta Seedlings

Etude et amélioration de la fiabilité d'un poromètre à diffusion utilisé en milieu naturel

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