25
q
T
= ((Fmt-Fme)/ (Fm-Fm’)) is the relaxation saturation value at
twenty minutes in the dark. (Values can be changed in Excel).
q
I
= ((Fm-Fmt) / Fm-Fm’)) Relaxation of q
I
starts at about forty minutes and can take up to
sixty hours. q
I
can be determined from the dark adapted Fm measurement and the saturation
pulse after 20 minutes used for q
T
or Fmt. (Values can be changed in Excel).
Puddle model parameters notes.
Puddle model event times for q
E
, q
T
and q
I
were taken from Lichtenthaler (1999). Descriptions
of q
E
, and q
I
are taken from Muller P., Xiao-Ping L., Niyogi K. (2001), q
T
is taken
from(Rubin, Johnson 2009) (Allen, Mullineau 2004), and Lichtenthaler (1999)
According to Baker (2008), the event times such as the time it takes for q
E
, used in the
quenching relaxation test, can change under field conditions.
Definitions - lake model parameters
Y(NPQ)
is a lake model quenching parameter that represents heat dissipation related to all
photo-protective mechanisms also called regulated heat dissipation. (David M. Kramer, Giles
Johnson, Olavi Kiirats & Gerald E. Edwards 2004) (Klughammer and Schreiber 2008).A low
Y(NPQ) at high light levels is an indication of sub-optimal photoprotective mechanisms.
(Klughammer and Schreiber 2008).
Y(NO)
is a lake model quenching parameter that represents all other components of non-
photochemical quenching that are not photo-protective. They include non-radiative decay,
and fluorescence. Part of Y(NO) includes photoinhibition (David M. Kramer, Giles Johnson,
Olavi Kiirats & Gerald E. Edwards 2004). Klughammer and Schreiber define Y(NO) as the
“fraction of energy that is passively dissipated in the form of heat and fluorescence mainly
due to closed PSII reaction centers”. Hendrickson calls Y(NO) constitutive heat dissipation. A
high Y(NO) value after dark adaptation is an indication of photodamage. (Klughammer and
Schreiber 2008).
q
L
is the lake model quenching parameter that represents photochemical quenching. It is a
measure of the fraction of still open PSII reaction centers. (David M. Kramer, Giles Johnson,
Olavi Kiirats & Gerald E. Edwards 2004).
Y(II)
= quantum yield of photosynthetic energy in PSII. The equation is
)
F/Fm’ or
(Fm’ – Fs) / Fm’.
