The activity of abscisic acid analogues as inhibitors of stomatal opening.

Ten analogues of abscisic acid (ABA) have been tested for their activity in assays based on the induction of stomatal closing on isolated epidermis of Commelina communis L., and the inhibition of opening on intact leaves of Xanthium strumarium L. Three of the analogues showed activity comparable to that of ABA on the stomata of Commelina. The same analogues also showed similar activity and persistence as ABA when applied to the leaf surfaces of Xanthium. Molecular requirements for activity on stomata agree closely with those for activity in the Avena coleoptile assay. The possible value of the analogues as antitranspirants is considered.