Abstract
Substantial errors can be introduced to estimates of leaf resistance (rl) obtained from diffusion porometers unless precautions are taken to reduce the leaf-cup temperature difference (Tleaf — Tcup) to acceptable levels prior to measurement. When Tleaf > Tcup, underestimation of leaf resistance occurs; the reverse applies when Tleaf < Tcup.
The effect is most pronounced under open-stomata conditions and declines as stomatal resistance increases. Under typical measurement conditions, Tleaf — Tcup 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 (rl = 1-2 sec cm−1). When Tleaf — Tcup = 5 C, the ratio drops below 0.5. Under high leaf resistance conditions (rl = 10-50 sec cm−1) the comparable ratios are approximately 0.9 and 0.7, respectively.
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Selected References
These references are in PubMed. This may not be the complete list of references from this article.
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