Histological and Histochemical Studies in Gum formation in Pterocarpus marsupium Roxb.

Kino gum in the young stem of Pterocorpus marsupium is produced in the cells of cortex and pith. Its formation is indicated by the deposition of granular tanniferous, proteinaceous and carbohydrate material (all are constituents of kino gum) in the intercellular spaces surrounding the cell. Enlargement and subsequent fusion of the intercellular spaces, involving splitting and/or partial breakdown of the middle lamella, results in an intercalary space which is later filled with more gummy substance. At the site of cell wall degradation, tannin is located. Apparent staining changes in DNA, RNA and starch grains during the gum development have also been studied.