Photoregulation of cytoplasmic streaming: Cell biological dissection of signal transduction pathway

In mesophyll cells ofVallisneria gigantea Graebner, an aquatic angiosperm, induction and cessation of rotational streaming of the cytoplasm are under the control of light. In this article, I would like to outline our study on the functional elements implicated in this light-dependent phenomenon, namely, photoreceptor systems, motile apparatus, and ion transport systems across the plasma membrane, and on the modes of interactions among them, with emphasis on the regulatory role of the calcium ion.