Changes in PET capacity were measured directly in isolated thylakoids
supplied with electron donor DCPIP and later repeated with
the addition of electron acceptor DPC at high light intensity (Fig. 2a).
Measurement of PET capacity from thylakoids isolated at different
stages of barley development showed little changes with time indicating
that the activity of PET chain changes little with development
and senescence of barley. PET capacity of the same samples with
DPC was comparable, so we can conclude that the PSII activity was
limited by photochemical step rather than by water splitting complex.
PET capacity of the same samples suspended in the mixture of
DMSO and buffer D was approximately two times lower indicating
that DMSO has negative influence on quality of thylakoids (Fig. 2b).
However, PET capacity was still measurable indicating that thylakoids
suspended in DMSO can be used for measurement of ROS
production.