Circular movement patterns of chloroplasts in leaf cells of pondweed (Elodea sp.)
This movie shows the circular movement pattern (cyclosis) of chloroplasts in leaf cells of pondweed, Elodea sp. This object is a very suitable material for practical courses on the dynamics of living cells, because the plants can be easily grown in an aquarium and because the leaves can be easily studied with a light microscope as they consist of only two layers of cells. Cyclosis in pondweed is not a unique feature, since most plant cells show some kind of cytoplasmic movement, where organelles and/or the surrounding cytosol move in a more or less similar velocity and direction. Besides cyclosis, saltatory, rotative, fountain-like and multistriate movements have been reported. The phenomenon of cytoplasmic streaming was already described in 1774 by Corti who remarked that particles were constantly in motion in internodal cells of Chara, a giant green alga. Nowadays, we know that such movements in plant cells essentially rely on the interaction between actin filaments, which belong to the cytoskeleton, and myosin molecules, in the presence of ATP as a source of chemical energy. It is assumed that cytoplasmic streaming promotes the exchange of metabolites in the cell.
Imaging/Web text: Department of General Instrumentation (KUN) (E.S. Pierson, B. van der Linden)
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