The effect of pH on stomatal sensitivity to abscisic acid

Abstract

Abstract. The sensitivity of stomata of Commelina communis L. to abscisic acid (ABA) was evaluated by analysing the initial rates of response to the compound at different hormone concentrations. This was carried out at pH 6.8 and pH 5.5. The data were modelled and statistically analyzed by means of a computer program employing non‐linear regression techniques and step‐down analysis of variance. The response kinetics as quantified in terms of three sensitivity parameters were found to differ significantly between the two pH values. This finding is discussed in relation to previous research on purified ABA‐binding proteins.