title: Spectral dependence of the light-induced geotropic response in Zea roots.
abstract: The induction by light of geotropic responsiveness in the primary roots of Zea mays L. (cv. Golden Cross Bantam 70) was found to be governed by the "all-or-none law". The response was induced by light energies above a threshold value, but the maximal curvature of geo-stimulated roots was constand irrespective of the light energy above that threshold. The action spectrum for this light effect showed a large peak at 650, a small peak at 410, and a shoulder at 663 nm. The effect of red light was not reversed by far-red light. Thus, the geotropic response in Zea roots may not be controlled by phytochrome.
authors.affiliation: Institute of Biological Sciences, University of Tsukuba, Sakura-mura, 300-31, Ibaraki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Fujii