Stomatal Metabolism: Carbon Dioxide Fixation and Labelling Patterns during Stomatal Movement in Commelina cyanea

Abstract

Epidermal strips floated on solutions with NaH14CO3 fixed 14C about three times as quickly when the stomata were opening or closing as they did when either open or closed. The proportions of the major fixation products-malate, aspartate, sugars and sugar phosphates, glycine, serine and alanine-were very similar during the opening, open and closed phases but, when closing, an appreciably higher proportion was diverted to sugars and sugar phosphates. There was a relatively greater leakage into the medium of labelled malate during the open, closed and closing phases than during opening.