In the present investigations, the localization of several enzymes (Acid Phosphatase, Peroxidase, succinic dehydrogenase, Phosphorylase, alkaline phosphatase, ATP-ase) and other substances in the guard and subsidiary cells as well as trichomes of the leaves of Phaseolus mungo, was carried out. Attempts were also made to follow the sequence of developmental stages starting with meristemoids and culminating in differentiated structures. The basic information thus obtained is used in interpreting the developmental physiology of stomatal differentiation as well as their cellular organisation. Histochemical observations made in the present studies are compared with the electron microscopical observations of Whatley (1972). It is proposed that mitochondria played a basic role in the functioning of the guard cells. The present studies also demonstrated activity of acid phosphatase in the guard cells and was localized in spherosomes. The latter varied in the activity for acid phosphatase and was dependent on the turgid level of the cell. Interestingly, enough localization of phosphatase could only be observed in spherosomes when the osmotic pressure in the cell was relatively low, once the osmotic pressure increased, the activity disappeared.

Acid Phosphatase↗

PubMed1975

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.

Acid Phosphatase↗

PubMed1975

Histochemical studies in stomatal apparatus of Phaseolus mungo Linn. II. Localization of phosphorylase.

Using histochemical techniques the presence of phosphorylase in the guard cells and subsidiary cells of Phaseolus mungo leaf has been demonstrated. The intensity of reaction is intense in the material collected at night while during the day collected leaves, both chloroplastic and cytoplasmic starch was absent. The functional significance of chloroplastic starch in the subsidiary cells in relation to the stomatal mechanism is discussed.

Chloroplasts↗

PubMed1974