biologia - Studia

CHLOROPHYLL FLUORESCENCE IN STATE TRANSITIONS
1-q P x 10 -2
10
9
8
7
6
5
4
3
2
1
0
M V1 V2 V3 V4 V5 V6
Fig. 3. Evolution of excitation pressure in photosystems’ state 1 and 2.
In conditions which reduce the light energy consuption in photochemistry
and thermic dissipation, the chlorophyll fluorescence increases, while an increase in
the excitation energy usage leads to fluorescence quenching (Kornyeyev et al., 2002).
The non-radiative dissipation of excitation energy in the photosystems’ antenna
decreases F 0 and F m proportionally, and dissipation from reaction centers reduces the
F m only (Gilmore and Yamamoto, 1991). The fluorescence quenching associated to
photoinhibition is not correlated directly to degradation of PS II reaction centers
(Briantais et al., 1988).
Quenching coeficients
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
qP
qN
M V1 V2 V3 V4 V5 V6
Fig. 4. Evolution of the photochemical (q P ) and non-photochemical (q N )
coefficients in photosystems’ state 1 and 2.
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