title: Reversal of blue light-stimulated stomatal opening by green light.
abstract: Blue light-stimulated stomatal opening in detached epidermis of Vicia faba is reversed by green light. A 30 s green light pulse eliminated the transient opening stimulated by an immediately preceding blue light pulse. Opening was restored by a subsequent blue light pulse. An initial green light pulse did not alter the response to a subsequent blue light pulse. Reversal also occurred under continuous illumination, with or without a saturating red light background. The magnitude of the green light reversal depended on fluence rate, with full reversal observed at a green light fluence rate twice that of the blue light. Continuous green light given alone stimulated a slight stomatal opening, and had no effect on red light-stimulated opening. An action spectrum for the green light effect showed a maximum at 540 nm and minor peaks at 490 and 580 nm. This spectrum is similar to the action spectrum for blue light-stimulated stomatal opening, red-shifted by about 90 nm. The carotenoid zeaxanthin has been implicated as a photoreceptor for the stomatal blue light response. Blue/green reversibility might be explained by a pair of interconvertible zeaxanthin isomers, one absorbing in the blue and the other in the green, with the green absorbing form being the physiologically active one.
authors.affiliation: Department of Organismic Biology, Ecology and Evolution, University of California, Los Angeles 90024, USA.
authors.forename: S
authors.initials: S
authors.lastname: Frechilla
authors.forename: L D
authors.initials: LD
authors.lastname: Talbott
authors.forename: R A
authors.initials: RA
authors.lastname: Bogomolni
authors.forename: E
authors.initials: E
authors.lastname: Zeiger
mesh_terms: D007887:Fabaceae / Q000502:physiology*; D008027:Light; D010946:Plants, Medicinal