A seed is the structure which contains the embryo of a plant (Johnson, 2004). Seeps have four adaptive values for plants; they include protection, nutrients, plant dispersal, and delayed growth. The seed coat provides protection for the embryo from disease and mechanical injury. Nutrients provide food for the embryo as it begins to grow. Plant dispersal is when the seeds are spread out to prevent competition for water and living space. Finally, delayed growth prevents the embryo from growing in unfavorable weather (Johnson, 2004). A seed consists of three main parts. These parts include the embryo, seed coat and cotyledon (endosperm).
An embryo is the part of the seed in which the new plant develops. The seed coat is the outer covering of a seed. It is the main form of protection. The cotyledon or endosperm is the hard outer case of a seed which holds the embryo and gives the embryo food supply (Ohanesian, 2001). Seed germination is the resumption of metabolic activity in a plant embryo after a period of dormancy. Water and oxygen are taken through the seed coat and the embryo begins to enlarge. The seed coat then breaks open and the radicle emerges followed by the shoot which contains leaves and the stem (Stack, 008). Yet, germination is not the same thing as plant growth. When a plant seed is exposed to proper conditions germination occurs. The proper conditions for seed germination include the right amount of water, oxygen and a proper temperature. There are other factors that affect seed germination. They include light, the depth at which you plant your seed, and pH levels (Stack, 2008). Based on the research I have conducted I have learned that you will be able to recognize a germinating seed when the radicle has emerged. This may take between 24-48 hours to occur.