SOME EFFECTS OF SODIUM AZIDE ON STOMATAL CLOSURE IN STACHYTARPHETA-INDICA

The progress of closing movements in the dark of stomata of excised, turgid leaves of Stachytarpheta indica exposed to azide for different time periods was studied. Depending on the concentration and duration of the treatment, azide may fail to affect, or it can retard or completely inhibit, closing of stomata induced by darkening of excised, turgid leaves. The effect of azide on stomatal movements in excised, turgid leaves wilting during illumination was also investigated. In general, although the progress of preliminary opening differed appreciably between leaves treated and not treated with azide, subsequent closure occurred almost to the same extent. The great disparity in stomatal behavior in treated and untreated leaves suggest that azide inhibits some metabolic process essential for guard cell operation. The cumulative concentration of azide in the leaf tissue determines the magnitude of the inhibitory effect.