Phytochrome-induced Increase of Fluorescein Translocation in Mung Bean Hypocotyls.

Moderate doses of red (660 nanometer) irradiation cause a rapid increase in the translocation of fluorescein in dark-grown mung bean hypocotyl (Vigna radiata L.) segments. The increase fails to appear following large doses of red (660 nanometers) irradiation. The red induced increase is prevented by a subsequent far red (730 nanometer) irradiation. Reversibility suggests the participation of phytochrome in the process. The increase in translocation is attributed to the generation of a positive electrostatic charge in the plasma membrane by some action of phytochrome on membrane molecules.