CHAPTER 6
ACRONYMS AND EQUATIONS
the fitting procedure yields estimates for
β
, the “photoinhibition pa-
rameter“(Platt et al., 1980), and ETR
mPot
, the maximum potential light-
saturated electron transport rate.
Platt et al. (1980) suggested to quantify photoinhibition by the
“Photoinhibition Index” (I
b
= PAR required to photoinhibit ETR
mPot
by
the factor of 1/e) according to:
β
mPot
b
ETR
I
=
With the results from curve fitting, WinControl-3 computes the ETR
m
and E
K
according to:
α
β
β
α
β
β
α
α
)
(
)
(
+
⋅
+
⋅
=
mPot
m
ETR
ETR
and
α
m
K
ETR
E
=
.
<REG2>
The function <REG2> is monotonically nondecreasing and,
hence, does not allow for photoinhibition:
)
tanh(
m
m
ETR
PPFD
ETR
ETR
⋅
⋅
=
α
Here, the
α
and ETR
m
are estimated by the fitting procedure. With the
latter two parameters, the E
K
is calculated as described above.
6.5
Literature Cited in Chapter 6
Bilger W, Björkman O (1990) Role of the xanthophyll cycle in photo-
protection elucidated by measurements of light-induced absorbance
changes, fluorescence and photosynthesis in leaves of Hedera canarien-
sis. Photosynth Res 25:173-185
Genty B, Briantais J-M, Baker NR (1989) The relationship between the
quantum yield of photosynthetic electron transport and quenching of
chlorophyll fluorescence. Biochim Biophys Acta 990: 87–92
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