Some plants fold and unfold their leaves following their inner circadian rhythm, which can be used as an indication parameter. But many plants do not have this characteristic. I read in some references that we can use the opening and closing of stomata as a circadian rhythm indicator. Is this true? Is there any other physiological parameters we can use to follow plant circadian rhythm (except gene expression)?
I want to perform an experiment in which we transfer the plants to continuous light and see how long the plants keep their circadian rhythm.