Abstract:he deposition of galactomannan in the seed endosperm cells from Sophora japonica L. starts 55～60 d after anthesis and ends at the time of seed maturation. The formation and accumulation of galactomannan in the cellwall of endosperm examined using histochemical method. It was found that galactomannan was at first formed in the vesicle of rough endoplasmic reticulum of the endosperm dells near the embryo and then expelled outside the plasmalemma. Afterwards, galactomannan deposition in the endosperm cell expanded towards the seed coat. Consequently, all cells of the endosperm, except those of the aleurone layer, became almost completely filled with galactomannan. In addition to the description, the site of galactomannan formation and the fluctuation of galactomannan during seed maturation were also briefly discussed.