Setting of optimal intensities of pulses:
Flash pulse setting
The optimum value of Flash pulse can be determined with QY measurement as shown in Fig.6 below. Before performing QY measurement
it is recommended to set the intensity of Super pulse to 80 %.
Please note that QY measurement should be performed with dark adapted sample, therefore the same sample (position on the leaf)
should not be used more than once unless dark adaptation follows the first measurement. The recommendation is to use a new sample
(new area on the leaf) for each QY measurements.
F
0
increases linearly with growing intensity of the Flash pulse.
The Flash pulse setting recommended by manufacturer is 30 %.
One can increase the intensity of Flash pulse for samples with
very low chlorophyll density. However, it should be noted that
high intensities of Flash pulse can cause undesirable “actinic
effect” as higher intensity High Flash pulse will initiate the
photochemistry. Changes in the Flash pulse will affect F
0
and the
QY value will be lower.
The optimal Flash pulse intensity is that at which the highest
value of QY is reached. This can be easily determined on one leaf
by measuring QY in few different spots with different flash pulse
settings. See (Fig. 6) below. In this example the optimal flash
pulse setting is 30%.
Super pulse setting
To determine the optimal intensity of Super pulse is to perform OJIP measurement with different Super pulse settings.
Please note that OJIP measurement should be performed with dark adapted sample. New sample (new section of the same leaf) should
be used for every measurement as exposure to super pulse will change photochemistry of the leaf in that section.
The Super pulse setting recommended by manufacturer is 80 %.
When performing the OJIP measurement with different intensities of Super pulse the Fv/Fm value will stop increasing when the optimal
level has been reached for the samples used (Fig. 7 and Fig. 8).
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