Abstract
Summary: In plant cells, various kinds of cytoplasmic particles exhibit active intracellular movements. To elucidate the regulatory mechanism for these movements, several approaches have been developed to visualize and quantitatively analyze the movements. Recently, using infrared microscopy and dynamic image processing technique, we have investigated the light-dependent cytoplasmic motility in Vallisneria gigantea epidermal cells. The cytoplasmic motility is an actin-dependent process and regulated by type II phytochrome. Moreover, the induction of cytoplasmic motility occurs in a few seconds of light irradiation, and in a subcellularly localized manner.