Photon Systems Instruments FluorPen FP 110 - Light Curve (LC) Protocols

© PSI (Photon Systems Instruments), spol. s r. o.
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7.3.3 LIGHT CURVE (LC) PROTOCOLS
The protocols called Light Curve (LC) were designed to acquire parameters for construction of Light Response Curve relating
the rate of photosynthesis to photon flux density. The method is based on successive measurements of the sample exposed
to a stepwise increase of light intensity. The effective quantum yields of photosynthesis are determined under various light
intensities of continuous illumination. Measurement is based on pulse modulated fluorometry (PAM).
Three predetermined LC protocols are available. These differ in number and duration of individual light phases and light
intensities as shown in Table3 below. The visual representation of the LC1 and LC2 protocols is shown in Fig. 10 and Fig.
11 below.
# of phases
Phase duration
Light intensities [µmol.m
-2
.s
-1
]
LC1
6
60s
10; 20; 50; 100; 300; 500
LC2
5
30s
100; 200; 300; 500; 1000
LC3
7
60s
10; 20; 50; 100; 300; 500; 1000
Tab. 3 LC Protocols.
The LC protocol includes the following measured and calculated parameters:
Abbreviation
Explanation
F
0
minimum fluorescence in dark-adapted state
F
m
maximum fluorescence in dark-adapted state
F
m
_Ln
‡
maximum fluorescence in light adaptation state
F
t
_Ln
‡
instantaneous fluorescence during light adaptation
QYmax*
maximum quantum yield of PSII in dark-adapted state - Fv/Fm
QY_Ln
‡
**
instantaneous PSII quantum yield induced in light
‡
n represents a sequential number of light phase
*Calculated as (F
m
– F
0
) / F
m
** Calculated as (F
m
_Lx – F
t
_Lx) / F
m
_Lx