ETYM Old Eng. seed, sed, as. saed, from sâwan to sow; akin to Dutch zaad seed, German saat, Icel. sâth, saethi, Goth. manasęths seed of men, world. Related to Sow to scatter seed, and cf. Colza.
The reproductive structure of higher plants (angiosperms and gymnosperms). It develops from a fertilized ovule and consists of an embryo and a food store, surrounded and protected by an outer seed coat, called the testa. The food store is contained either in a specialized nutritive tissue, the endosperm, or in the cotyledons of the embryo itself. In angiosperms the seed is enclosed within a fruit, whereas in gymnosperms it is usually naked and unprotected, once shed from the female cone.
Following germination the seed develops into a new plant.
Seeds may be dispersed from the parent plant in a number of different ways. Agents of dispersal include animals, as with burs and fleshy edible fruits, and wind, where the seed or fruit may be winged or plumed. Water can disperse seeds or fruits that float, and various mechanical devices may eject seeds from the fruit, as in the pods of some leguminous plants (see legume).
There may be a delay in the germination of some seeds to ensure that growth occurs under favorable conditions (see after-ripening, dormancy). Most seeds remain viable for at least 15 years if dried to about 5% water and kept at -20şC/-4şF, although 20% of them will not survive this process.
(Homonym: cede).
1. A mature fertilized plant ovule consisting of an embryo and its food source and having a protective coat or testa.
2. A small hard fruit. + prikaži više

ETYM Latin, from the root of serere, satum, to sow. Related to Sow to scatter seed.
The thick white fluid containing spermatozoa that is ejaculated by the male genital tract; SYN. seed, seminal fluid, ejaculate.
See sperm.

Or semen; The fluid containing the male gametes (sperm cells) of animals. Usually, each sperm cell has a head capsule containing a nucleus, a middle portion containing mitochondria (which provide energy), and a long tail (flagellum).
In most animals, sperm cells (sometimes called “sperm” for short) are motile, and are propelled by a long flagellum, but in some (such as crabs and lobsters) they are nonmotile. The term is sometimes used for the motile male gametes (antherozoids) of lower plants. The human sperm is 0.005 mm long and can survives inside the female for 2–9 days.
Sperm counts have fallen by 50% worldwide since 1940, according to a Danish study 1990. This reduction may be due to increases in pollution as a number of pollutants, including some petroleum by-products and polychlorinated biphenyls, mimic the effects of the female hormone estrogen on cells.
The male reproductive cell; the male gamete; SYN. sperm cell, spermatozoon. + prikaži više