CIRAS-3 Operation Manual V. 1.09
91
Initial Fluorescence
phiPSII-SP (
ϕPSII-Single-Pulse)
. If selected, there is no need to dark adapt
the leaf and measurements can begin right away and a single, saturating pulse
applied to the light-adapted leaf sample. The single pulse duration and
intensity can be set in the lower part of the screen under “Saturating Light”.
phiPSII-MP (
ϕPSII-Multi-Pulse)
. If selected, there is no need to dark adapt
the leaf and a “Multi-Pulse sequence can begin right away with multiple,
saturating pulses applied to the light-adapted leaf sample. The Multi-Pulse
duration and intensity settings (up to 5 steps) can be set in the lower part of the
screen under “Saturating Light”.
Fv/Fm.
If selected, you will need to allow the plant to dark acclimate prior to
measurement. Set the
Initial Dark Adapt Period
of your choosing. Longer
dark adapt period are required for plants that have been under high light and
shorter periods for plants that have been in the dark or low light.
To determine the effective dark adaptation period you will need to identify the
point at which F
v
/F
m
does not increase with an associated increase of the dark
adaptation period. In the example below, the leaf sample is sufficiently dark-
adapted after 20 minutes, since longer dark adaptation periods did not result in
higher F
v
/F
m
values. Note that prior light exposure (intensity, duration)
significantly affects the minimum effective dark adaptation period required to
fully re-oxidize (open) PSII photochemistry in the leaf sample.
DA period
(minutes)
5
10
15
20
25
30
F
v
/F
m
0.63
0.71
0.78
0.81
0.80
0.81
Repeated
Fluorescence
Measurement
Only one valid selection can be made and the measurement recorded at
recording intervals of your choosing. This will be influenced by your choice of
Recording mode (Manual, Timed, or Response Curve).
None
. If selected, there will be no chlorophyll fluorescence measurements
performed after a photosynthesis measurement has been recorded.
