It is essential to have Ca2+ in the extra cellular solution to ensure the maintenance of selective permeability, which is responsible for membrane integrity.
It is also well known that calcium is an integral part of the cell wall where it provides stability to the cell wall. Calcium helps bind together neighbouring cell walls and maintains the integrity and the semi permeable properties of membranes (Poovaiah et al., 1988). It appears to serve as an intermolecular binding agent that stabilizes pectin-protein complexes of the middle lamella of the cell wall. Thus it is suggested that the higher calcium content observed in CaCl2 sprayed pineapple could be the reason for less severity of black heart disorder. In