title: Abscisic Acid in Leaf Epidermis of Commelina communis L.: Distribution and Correlation with Stomatal Closure.
abstract: Changes in the abscisic acid (ABA) content of epidermis and mesophyll of isolated Commelina communis L. leaves were followed and compared to changes in diffusion resistance during a water stress treatment. Diffusion resistance increased within 15 min before a rise in the ABA content of the epidermis could be determined. By application of (14)C-labelled ABA to isolated leaves via the transpiration stream it was found that the minimal amount of ABA to induce stomatal closure was in the range of 0.4 fmol per stomatal complex. Isolated epidermis was treated with tritiated ABA and subjected to microautoradiography. The stomatal complexes showed an accumulation of radioactive material. This accumulation was observable in living as well as in non-living, heat- or cold-treated epidermis. The results are discussed in relation to the hypothesis that ABA regulates stomatal closure in water-stressed leaves.
authors.affiliation: Institut für Allgemeine Botanik und Botanischer Garten Hamburg, Ohnhorststraße 18, D-2000 Hamburg 52.
authors.forename: K
authors.initials: K
authors.lastname: Dörffling
authors.forename: D
authors.initials: D
authors.lastname: Tietz