UA49

UA49 (30 μM; during voltage clamp recording) potently inhibits multiple Arabidopsis guard cell voltage-dependent K⁺ channels, with the strongest effect on KAT1, when applied to Xenopus laevis oocytes expressing the channels^[1].
UA49 (10 μM; 10 min) inhibits inward K⁺ currents but does not alter Ca²⁺-permeable channel activity in Arabidopsis thaliana guard cell protoplasts^[1].
UA49 (10 μM; 2-3 h) induces stomatal closure and inhibits stomatal opening in Arabidopsis thaliana leaf epidermal strips, reducing stomatal aperture to levels comparable to abscisic acid treatment^[1].
UA49 (10 μM; 30 min) reduces cytosolic K⁺ concentration in Arabidopsis thaliana guard cells, consistent with induction of stomatal closure^[1].
UA49 (10 μM; 30 min) induces a sustained increase in cytosolic Ca²⁺ concentration in Arabidopsis thaliana guard cells, dependent on apoplastic Ca²⁺ influx and functional inward K⁺ channels^[1].
UA49 (10 μM; 10 min) increases endoplasmic reticulum Ca²⁺ concentration in Arabidopsis thaliana guard cells^[1].
UA49 (10 μM; 2 h) induces stomatal closure in Arabidopsis thaliana independently of the ABA receptor and OST1 kinase pathways, requires the SLAC1 anion channel (via phosphorylation sites distinct from ABA), and is partially dependent on cytosolic Ca²⁺ signals^[1].