ULTRASTRUCTURE OF THE MATURE UNGERMINATED RICE (ORYZA SATIVA) CARYOPSIS. THE STARCHY ENDOSPERM

Abstract

The structure of the starchy endosperm of rice ( Oryza sativa ) was studied by using light and transmission electron microscopy coupled with proteolytic enzyme digestions. The starchy endosperm was divided into two regions, the subaleurone and central, based on the number and types of protein bodies observed. The subaleurone region contained three different types of membrane bounded protein bodies—large spherical, small spherical, and crystalline protein bodies. The small spherical protein bodies were most numerous and the large spherical ones were least numerous. The crystalline protein bodies displayed crystal lattice fringes and were a composite of smaller angular components. The central region lacked both the small spherical and crystalline protein bodies. The large spherical protein bodies of this region were located in pockets of densely stained proteinaceous material. In contrast to the relatively well preserved cytoplasm of the subaleurone region, the central endosperm zone consistently was poorly preserved.