Appendix 3. Photosynthesis Equations Used in CIRAS-2
CIRAS-2 Operator's Manual Version 2.04
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H is calculated from the photon flux incident on the cuvette (Q), taking into account the ratio of infrared to
PAR in the light source, transmission through the cuvette window (
Trans
), and reflection/absorption by the
leaf: (H = Q x
Trans
).
The following approximation is made in the program:
(3.2)
From this we derive:
Step 4.0
Derive i) saturated vapor pressure at leaf temperature (
e
leaf
) from
T
leaf
and ii) stomatal
resistance (
r
s
)
(4.1)
From
Reference 2
:
(4.2)
Stomatal resistance (to water vapor) is derived by:
(4.3)
An alternative expression of
Step 2.4
is:
(4.4)
Because,
