© PSI (Photon Systems Instruments), spol. s r. o.
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Setting of optimal intensities of pulses:
Flash pulse setting
The optimum value of Flash pulse you can identify with QY measurement. Before QY measurement is recommended to
set the intensity of Super pulse on 80 %.
Please note that QY measurement should be performed with dark adapted sample. New sample is needed for every
measurement (measured point of the leaf can be inhibited after measurement).
F0 is increasing linearly with growing intensity of Flash pulse. Increasing Flash pulse is not affecting background value.
The Flash pulse setting recommended by manufacturer is 30 %. You can increase the intensity of Flash pulse in case of
sample with very low chlorophyll density. Please note that high intensities of Flash pulse can cause undesirable “actinic
effect”. In this case the Flash pulse initiates the photochemistry. The Flash pulse affects F
0
and the QY value will be lower.
The Flash pulse intensity at which the highest value of QY is reached is optimal for your sample (Fig. 6).
Fig. 6 QY measurement performed with different intensities of Flash pulse. Optimal setting is highlighted in red rectangle.
Super pulse setting
Best way to recognized the optimal intensity of Super pulse is perform OJIP measurement.
Please note that OJIP measurement should be performed with dark adapted sample. New sample is needed for every
measurement (measured point of the leaf can be inhibited after measurement).
The Super pulse setting recommended by manufacturer is 80 %.
Perform the OJIP measurement with different intensities of Super pulse. When the F
v
/F
m
value stops growing during the
OJIP measurement with various Super pulse intensities, the Super pulse intensity is optimal for your samples (Fig. 7).
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