Development of Starch Endosperm Cells and Amyloplasts in Wheat

To clarify the development and growth rule of endosperm cell and amyloplast,wheat caryopsis at different developmental days was used as the experimental material in the study.The shape,number and the development process of the starch endosperm cells and amyloplasts were analysed by observation of semi-thin sections and separation of starch endosperm cells.The results were as follows:(1) The starch endosperm cell was polyhedron shape,there were two kinds of amyloplasts,the large amyloplast was in pebble-shape,and the small amyloplast was in spherical-shape;(2)The growth of starch endosperm cell presented S-curve during the endosperm development.The starch endosperm cell grew fastest during 16-24 d after flowering;(3) The proliferation and growth of large amyloplast mainly occurred at 4-16 d after flowering.The small amyloplast appeared in large numbers at 16d later after flowering and then gradually increased in numbers.At late stage,the number of small amyloplasts accounted for more than 90% of the total amyloplast in starch endosperm cell.(4) The nuclei of starch endosperm cell was degenerated in middle and late stage of development,while amyloplast still proliferated and grew during the nuclei degenerated.