2.8 Conductance of the electron transport chain (gETC)
To estimate the conductance of the electron transport chain(gETC) , we used a similar experiment setting to the previous section monitoring the redox state of PSI with slight modifications. The saturating pulse was given under darkess simultaneously with the termination of AL. Notably, a 100-ms width SP at a PPFD of 8000 μmol m-2s-1 was applied and the decay in absorbance followed upon transition from the 100 ms SP to darkness (Klughammer & Schreiber, 1994; Klughammer & Schreiber, 2008). This intensity was found to be saturating across all conditions used. Under these conditions, application of a flash induced a rapid rise in the absorbance signal, with no decrease during the duration of the flash (not shown). The absorbance decay curve under such conditions (ctrl or salt) approximated closely to a first-order reaction and was fitted well with a mono-exponential curve, yielding a rate constant. This was taken as a measure of the conductance of the electron transport chain (Golding & Johnson, 2003; Stepien & Johnson, 2009).