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Leaf Temperature Effects on Measurements of Diffusive Resistance to Water Vapor Transfer 1

Authors :
Morrow, P. A.
Slatyer, R. O.
Publication Year :
1971

Abstract

Substantial errors can be introduced to estimates of leaf resistance (r(l)) obtained from diffusion porometers unless precautions are taken to reduce the leaf-cup temperature difference (T(leaf) - T(cup)) to acceptable levels prior to measurement. When T(leaf)T(cup), underestimation of leaf resistance occurs; the reverse applies when T(leaf)T(cup).The effect is most pronounced under open-stomata conditions and declines as stomatal resistance increases. Under typical measurement conditions, T(leaf) - T(cup) values of the order of 1 C induce a reduction in the ratio of the apparent to true leaf resistance to about 0.8 when the leaf resistance is low (r(l) = 1-2 sec cm(-1)). When T(leaf) - T(cup) = 5 C, the ratio drops below 0.5. Under high leaf resistance conditions (r(l) = 10-50 sec cm(-1)) the comparable ratios are approximately 0.9 and 0.7, respectively.

Subjects

Subjects :
Articles

Details

Language :
English
Database :
OpenAIRE
Accession number :
edsair.pmid..........bfc68920099160e11ac37b98125d14fe