title: Proton excretion and cell expansion in bean leaves.
abstract: Light-induced expansion of Phaseolus vulgaris L. leaf cells is accompanied by increased cell-wall plasticity. The possibility that leaf-cell walls are loosened by excreted protons has been investigated. First, light causes acidification, detected at the leaf surface, within 5-15 min. Growth starts 10-20 min after exposure to light. Second, exogenous acid induces loosening of isolated leaf cell walls. Third, infiltration of the tissue with a neutral buffer inhibits light-induced growth. Fourth, fusicoccin stimulates growth of as well as H(+) excretion by bean leaf cells, without light. These findings show that the acid-growth theory is applicable to light-induced growth of leaf cells, and indicate that light-induced proton excretion initiates cell enlargement in leaves.
authors.affiliation: Department of Botany, University of Washington, 98195, Seattle, WA, USA.
authors.forename: E
authors.initials: E
authors.lastname: Van Volkenburgh
authors.forename: R E
authors.initials: RE
authors.lastname: Cleland