Histochemical studies in stomatal apparatus of Phaseolus mungo Linn. I. Localization of enzymes and structural material.

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.