Botany - Transport in Plants Question with Solution | TestHub

According to${\mathrm{K}}^{+}-{\mathrm{H}}^{+}$pump theory during the closure of stomata, ABA stops the energy dependant proton pump in guard cell, thus${\mathrm{K}}^{+}$diffuses out of the cell and${\mathrm{H}}^{+}$enters inside, which combines with malate ion to form malic acid. OP of guard cells decreases thus stomata close.