seed

seed fertilized and ripened ovule, consisting of the plant embryo, varying amounts of stored food material, and a protective outer seed coat. Seeds are frequently confused with the fruit enclosing them in flowering plants as in the grains and nuts. The seed-bearing plants are the highest in the evolutionary scale; in lower plants (e.g., mosses and ferns) the spore is the agent of propagation. True seeds vary in size from the dustlike seeds of some orchids to the large seed contained in the coconut. The period of dormancy undergone by many seeds before germination also varies; the mangrove seed may sprout inside a fruit still hanging on the tree, while a seed of a sacred lotus dated at about 1,200 years and one of a date palm about 2,000 years old have been germinated. Long dormancy in some seeds is ensured by their extremely hard coats, which have to be scratched or split to force sprouting. In plant breeding , the source of pollen for fertilization is carefully controlled to produce the desired qualities in seed; under natural conditions a plant grown from seed may be quite different genetically from its maternal plant (see fertilization ).

seed
1. In the sexual reproduction of seed plants (Spermatophyta), the discrete body from which a new plant develops. Formed from a fertilized ovule, the seed comprises an outer coat (testa) enclosing a food store and an embryo plant.

2. Any plant or animal structure concerned with propagation.

seed Part of a flowering plant that contains the embryo and food store. It is formed in the ovary by fertilization of the female gamete (see pollen). Food may be stored in a special tissue called the endosperm, or may be concentrated in swollen seed leaves (cotyledons). Seeds are the unit of dispersal of angiosperms and conifers. See also fruit; germination