Can anyone on this listserver help me ?
Recently I completed several experiments to investigate the temporal effect
of the diurnal irradiance cycle on the photosynthesis of a species of
seagrass. I am using chlorophyll a fluorescence to monitor the condition of
PSII. One experiment was carried out on field collected specimens, and
produced a Fv/Fm curve with a midday trough and dawn and dusk maxima. This
could be a photoprotective response to prevent excess irradiance during the
midday peak solar insolation.
However, when the experiment was run using cultured specimens from the same
location, the Fv/Fm curve was inverted, with a midday peak and dawn and
dusk minima. The light was constant and the same as the plants had been
cultured at for 6 months prior to the experiment.
Why is the Fv/Fm curve now showing a midday peak, if it was simply
responding to the level of irradiance it should go straight to maxima and
remain there until the lights are turned off ?
Any suggestion, or ideas would be greatly appreciated.
Regards Peter
