Seeds are unique, protective structures that contain embryos of the developing plant. They often undergo physiological dormancy, which may require a period of moist chilling or stratification.
The term “seed” can also refer to a random value used by Minecraft players that determines the world they will spawn in when starting a new game. It is similar to the randomized number that is used in predictive modeling for reproducible results.
Definition
A seed is a small, hard part of a plant that produces a new plant when sown. The term is also used to refer to a value that helps generate a random number or other value in computer programming or encryption.
Biologically, a seed is the mature ovule containing an embryo in a dormant state that will develop into a new plant when sown. A seed may have one embryo (Monocotyledons) or two embryos (Dicotyledons). It has a storage protein, the endosperm, which provides most of its nutrients; this tissue is usually thick and leathery. The epicotyl is a stem-like appendage from the point of attachment of the cotyledons to the embryonic axis; it will become the shoot when the seed sprouts.
A seed can be a hexapod or ovoid, ellipsoid, lenticular, oblong, or reniform. Some seeds are striated, with parallel longitudinal lines. The cotyledons can be feathery or papery, and are a source of food for the developing plant in non-endospermic monocots.
Origin
Seeds are the characteristic reproductive body of the flowering plants (angiosperms) and gymnosperms, including conifers and cycads. They are also found in some nonflowering plants such as ferns.
A seed is a miniature undeveloped plant with stored food for its own growth after germination and a protective coat. Its emergence, along with pollen and sporophytes, marked an evolutionary breakthrough that enabled plants to reproduce independently of water.
Unlike spores, a seed has an embryo with one or two cotyledons. The cotyledon is a shield-shaped region that connects the radicle and plumule. In monocot seeds the cotyledon forms part of the endosperm and is used as a source of food. In dicot seeds, the cotyledon and the embryo combine to form the seed leaf. Seeds also possess a thick coating that protects the embryo from desiccation and enables it to delay germination until conditions are optimal for development.
Functions
Seeds perform several functions for the plants that produce them. These functions include nourishment of the embryo, dispersal to a new location, and dormancy during unfavorable conditions.
A mature seed contains a diploid (2N) embryo, and some food storage tissue (endosperm). The embryo develops from a fertilized egg (zygote). In some seeds, the endosperm is absent because the embryo receives nourishment from the seed’s own cotyledons.
Non-endospermic seeds require stratification to break down physiological dormancy. This is accomplished by placing the seeds in a container and subjecting them to alternating periods of moist-chilling and cold temperatures. During this process, the seeds sprout faster than they would in normal conditions.
Uses
Seeds are the major food source for many animals and also provide long-term storable foods, such as nuts. They also serve as an excellent means of dispersal for plants that cannot reproduce by producing spores, such as gymnosperms and many conifers. In human culture, seeds are important sources of food and medicinal products, although modern synthetic chemicals have replaced many plant-based remedies. The study of this interaction between people and the plants they depend on is known as ethnobotany.
Seeds are used for the cultivation of grains, legumes, and oilseeds. They are also the basis for the production of cotton, linseed, and sunflower seed oil. Seeds of some shrubs and trees have hard, impervious seed coats, requiring special storage conditions to break their dormancy. Seeds are also used for birdseed and fish feed, as weights for balances, as toys by children, such as Conkers, and for making beads from Job’s tears, Chinaberry, rosary pea, and castor bean.
