Histochemical studies in stomatal apparatus of Phaseolus mungo linn. IV. Mechanism of stomatal action.

The histochemical studies were carried out in the open and closed stomata of Phaseolus mungo leaves. Several enzymes like, Acid phospatase peroxidase, succinic dehydrogenase, phosphorylase, alkaline phosphatase, ATP-ase etc. were localized in the guard and subsidiary cells of epidermal peel. On the basis of cytochemical localization, enzyme activity was precisely interpreted. In the light of fluctuations in the localization, activities of different enzymes, an attempt is made to provide the functional interpretation of stomatal mechanism. We have attempted to correlat our observations in relation to diurnal metabolisms. Our studies suggest that starch-sugar inter-changes played a vital role in the stomatal regulation. We are also inclined to believe that besides guard cells, subsidiary cells also influenced the turgid conditions. A model based on available facts in collaboration with our own studies is presented which tends to explain the stomatal regulation.