Action Spectrum for the Opening of Albizia Julibrissin Pinnules, and the Role of Phytochrome in the Closing Movements of Pinnules and of Stomata of Vicla Faba

Abstract

The opening movements of both V. faha stomata and A. julibris8in pinnules have been shown previously to depend on a redistribution of potassium ions under the influence of light. Action spectra for both systems show peak effectiveness in blue light, at 440 nm, but for pinnule opening in A. julibri88in there is a subsidiary peak in the far red (720 nm). However, opening in far red shows an initial lag period, whereas opening in blue light is rapid. The action spectrum for pinnule opening was not influenced by leaf age, the presence or absence of CO2, or by simultaneous red light.