The degeneration of nucleus and ultracytochemical localization of hydrolytic enzymes during starchy endosperm development in rice were observed using transmission electron microscopy. With the developing of starchy endosperm cells, several distinct morphological features of PCD existed in nucleus, such as deformation of nucleus, condensation of chromatin, swelling of perinuclear space. Electron dense granules similar to the condensed chromatin were encroached by the vacuole and the dilated endoplasmic reticulum fragments. Localization of hydrol...