ABSTRACT
The seed habit is a significant advancement in the evolutionary history in the plant kingdom and has bestowed several advantages to seed-bearing plants. Seed structure is intimately concerned with the infection caused by plant microorganisms. Seed morphology and anatomy reveal the probable pathways of infection as well as the barriers to infection. A viable seed consists of an embryo, a protective covering, and the reserve food material. Seeds also contain other minor reserves, some of which are nutritionally undesirable or even toxic, e.g., alkaloids, inhibitors, lectins, and phytins. The cuticula of different components of seed are distinct. Variations in exomorphic seed characters are considerable and many of them are important with respect to the functional attributes of seeds. Seeds may be monochrome or marked by points, mottles, and streaks. White, brown and brown derivatives, and black are by far the most common seed colors. The surface of the seed coat may be smooth or sculptured.
