<Table> <Tr> <Td> I Zygote II Proembryo III Globular </Td> <Td> IV Heart V Torpedo VI Mature Embryo </Td> </Tr> </Table> <Tr> <Td> I Zygote II Proembryo III Globular </Td> <Td> IV Heart V Torpedo VI Mature Embryo </Td> </Tr> <P> Angiosperm (flowering plants) seeds consist of three genetically distinct constituents: (1) the embryo formed from the zygote, (2) the endosperm, which is normally triploid, (3) the seed coat from tissue derived from the maternal tissue of the ovule . In angiosperms, the process of seed development begins with double fertilization, which involves the fusion of two male gametes with the egg cell and the central cell to form the primary endosperm and the zygote . Right after fertilization, the zygote is mostly inactive, but the primary endosperm divides rapidly to form the endosperm tissue . This tissue becomes the food the young plant will consume until the roots have developed after germination . </P> <P> After fertilization the ovules develop into the seeds . The ovule consists of a number of components: </P>

In a seed the seed coat is composed of tissues belonging to