Room temperature chlorophyll fluorescence
The activities of PSI and PSII were measured in dark-adapted
exponentially growing cultures with a Dual-PAM-100 system (Heinz Walz
GmbH, Effeltrich, Germany) as described in Szyska et al. (2007). All
samples were supplemented with 10 mM sodium biocarbonate and
measurements were performed in a water-jacketed cuvette at the
corresponding growth temperatures. The fluorescence parameters
FV/FM(maximum photochemical efficiency), qL
(photochemical quenching or
proportion of open PSII reaction centers), Φ (PSII) (quantum yield of
photochemistry), and Φ (NPQ) (nonphotochemical energy dissipation from
antenna quenching), and Φ (NO) (energy dissipation from non-regulated
processes) were calculated during steady state photosynthesis at the
growth temperature/irradiance/salinity regimes. Energy partition
parameters of PSI were: quantum yield of PSI (ΦPSI), acceptor side
limitation (ΦNA), and donor side limitation (ΦND) (Schreiber &
Klughammer, 2008).