Relation Between Seed Life Cycle and Cell Proliferation. Metabolic Changes in Seed Germination

A seed is considered as an embryonic plant covered with a defensive outer veil. Seed is the next generation of plant as embryo. The creation of seed is an essential criterion in the process of reproduction of seed plants. After fertilization between pollen grain and ovule, zygote is formed and the development of zygote provides the creation of embryo. Seed is referred to as the outcome of ripened ovule, and seed coat is derived from the exterior part of ovule. Seed in suitable environment germinates to a seedling, and finally the fully matured plant by fertilization produces seed, which is developed by three important processes like histo-differentiation, cell enlargement and expansion, slowing of dry matter accumulation, and pausing of physiological maturity. Therefore, the seed life cycle comprises germination of seed to a plant and fertilization of ovule and pollen to a seed. The life cycle of seed is connected with cell proliferation regulated by the mechanism of a network system of signaling pathways that helps in the regulation of various components of seed life cycle. The germination of seed occurs via a series of chemical changes to form seedling from a seed embryo. Germination is nothing but reactivation of the metabolic pathways, resulting in the growth and outcome of radicle and plumule from seed. During the process of germination, the synthesis of RNA, DNA, and protein content of embryo occurs through various metabolic changes inside embryo. This chapter highlights the anatomy of a seed, development of seedling from seed by germination, and formation of seed by fertilization, i.e., seed life cycle, cell proliferation, and signaling mechanism, relation between seed life cycle and cell proliferation and the metabolic changes regarding the production of nucleic acid such as DNA, RNA, and chemical changes of carbohydrate, lipid, and protein content in seed.