Abstract
We are investigating the regulatory mechanism of cytoplasmic motility in plant cells. Using a custom-made dynamic image analyzer, the cytoplasmic motility was efficiently quantified as the deviation of changes in the brightness of individual pixels on digitized images sequentially taken by infrared light microscopy. These procedures enabled us to detect a rapid, localized induction of cytoplasmic motility in epidermal cells of the aquatic angiosperm Vallisneria gigantea. The cytoplasmic motility were photoreversibly regulated by type II phytochrome. The induction of cytoplasmic motility took place in a patchy manner in whole irradiation and only in the exposed region in microbeam irradiation. The induction became detectable a few seconds after the start of light irradiation. This response can be categorized as one of the most rapid responses under the control of type II phytochrome reported to date. Analyses in other plants will be briefly mentioned.
