F Fluorescence - Walz MINI-PAM-II Manual

Chapter 6
6.3 F Fluorescence
0
Usually, measuring light intensity is adjusted to reach F
cence levels around 500 mV (for a definition of F
5.1.1, page 32). Theoretically, the F
The latter upper value is derived from the assumption that the
maximum F /F
V
nal saturation occurs at 4000 mV (see equation below, Table 5).
If required, measuring light can be adjusted (Fig. 39, page 72).
Table 5: Maximum F
  ( F
F
   
M
=
V
F
 
M
Max
( )
with F F
V M
Max
( )
F
= 640
0
Max
At low signal levels, signal height can be increased by increasing
measuring light intensity. At too high intensities, the measuring
light might drive photosynthesis to some degree. Therefore, test
if switching on measuring light results in a stable signal or if any
signal increase occurs. In the latter case, the effective measuring
light intensity must be decreased either by reducing the ampli-
tude of measuring light (measuring light intensity) or by reducing
measuring light frequency or both (Section 7.3.1, page 70).
46
Hints
of any sample is 0.84 und from the fact that sig-
M
of a Dark-acclimated Leaf
0
( )
) − F
Max
0
Max
F
( )
M Max
= . 0 84
should stay below 640 mV.
0
(F ) , maximum possible F
M Max
4000.
(F ) , unknown maximum F
0 MAX
(the F associated with this F
M
smaller F , is not saturating).
0
(F /F ) , assumed maximum possible
V M Max
PS II photochemical yield.
fluores-
0
see Section
0
value =
M
value
0
, or with
0