here’s part of the results of an experimental stress physiology class that i took last summer…
in what must have been one of the most open-minded classes i ever took (meaning that we could really influence the topics and experiments), my friend barbara and i studied three aspects of the common wood sorrel (oxalis acetosella): protective leaf movements, photo inhibition and heat resistance.
the following time lapse video shows protective leaf movements, which are a “deliberate” reaction of this little plant to a sudden input of intense, direct sunlight:
on the base of each of three leaflets, turgor controlled pulvinar cells function as a hinge to increase or decrease the leaf angle of the leaflets. such nastic leaf movements can be triggered by a number of exogenous factors such as light (photonasty), temperature (thermonasty) but also by internal
the concluding course discussion was held as an inofficial “conference of alpine stress physiology”, with poster presentations of all participants.
you can find more information about our oxalis experiments in barbara’s and my scientific poster: Leaf movements, photo inhibition and heat resistance in Oxalis acetosella L. (PDF)