HANSATECH FMS1, Manual

Page: 65 / 86

65 Section 2: Software Installation, System Operation, Data Handling
© 2017 Hansatech Instruments Ltd
photosynthetically
active radiation
Fs Steady state
fluorescence yield
Bits
Fm' light-adapted
fluorescence maximum
Bits
f
PSII
quantum efficiency of
PSII
No Units = (Fm’-Fs) / Fm’
(Genty et al. 1989)
qp photochemical
quenching co-efficient
No Units (Fm’-Fs) / (Fm’- Fo)
qNP Non-photochemical
quenching co-efficient
No Units = (Fm-Fm’) / (Fm-Fo)
NPQ Alternative definition of
non-photochemical
quenching
No Units = (Fm-Fm’) / Fm’
ETR Electron transport rate No Units
=PAR * 0.5 *
f
PSII *
0.84
Fs
The steady state fluorescence yield (Fs) is automatically measured when the PSII and PSIIR
functions are active. However, there may be occasions where it is desirable to log the Fs value
without initiating a saturating pulse. This should be done by clicking the “Fs” measurement
function. When activated the following 1.6 sec of data are averaged with the result written as Fs
in the “Parameters Window”.
Fo
Measurements of Fo’ can be made independently of the PSIIR function by operating the “Fo’”
button. When active the actinic light is switched off, far-red light initiated for 5 sec and the
fluorescence decline tracked. The minimum value is written to the “Parameters Window” as Fo’.
At the end of the far-red pulse the actinic light is switched back on to its original setting.
THE SAMPLE SHOULD BE SHADED FROM AMBIENT LIGHT DURING THE
FAR-RED ILLUMINATION TO ENSURE THAT PREFERENTIAL PSI EXCITATION
OCCURS. IF TOO MUCH AMBIENT LIGHT IS PRESENT THE EFFECT THE FAR-RED
ILLUMINATION WILL BE SWAMPED.
Logging PAR and Temperature
The “PAR” and “Temp” functions on the instrument toolbar allow logging of incident PPFD and
temperature at the sample. They write a latest measurement displayed on the instrument
monitoring bar to the “Parameters Window”. It is therefore important that the instrument