A seed [siːd] (help·info) (in some plants, referred to as a kernel) is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. The jalapeño ( Nahuatl: xalapeño ( or /ˌhæləˈpeɪnjoʊ/ Castilian, Mexican) is a medium to large size Chili pepper Plant embryogenesis is the process that produces a plant embryo from a fertilised ovule by asymmetric cell division and the differentiation of undifferentiated cells into tissues and Plants are living Organisms belonging to the kingdom Plantae. Food storage is both a traditional domestic skill and is important industrially It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant. Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells Gymnosperm (Gymnospermae are a group of Spermatophyte seed-bearing Plants with Ovules on the edge or blade of an open Sporophyll, which are The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group For soil improvement see Fertilization (soil. The formation of the seed completes the process of reproduction in seed plants (started with the development of flowers and pollination), with the embryo developed from the zygote and the seed coat from the integuments of the ovule. Reproduction is the Biological process by which new individual Organisms are produced A flower, also known as a bloom or Blossom, is the reproductive structure found in Flowering plants (plants of the division Magnoliophyta, also Pollination in angiosperms and Gymnosperms is the process that transfers pollen grains, which contain the male Gametes (sperm to where the female An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular A seed (in some plants referred to as a kernel) is a small embryonic Plant enclosed in a covering called the seed coat usually with some stored

Seeds have been an important development in the reproduction and spread of flowering plants, relative to more primitive plants like mosses, ferns and liverworts, which do not have seeds and use other means to propagate themselves. The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group Mosses are small soft Plants that are typically 1–10  cm (0 A fern is any one of a group of about 20000 Species of Plants classified in the phylum or division Pteridophyta, also known as Filicophyta The Marchantiophyta are a division of Bryophyte Plants commonly referred to as hepatics or liverworts. This can be seen by the success of seed plants (both gymnosperms and angiosperms) in dominating biological niches on land, from forests to grasslands both in hot and cold climates. In Ecology, a niche (pronounced nich nēsh or nish A shorthand definition of niche is how an organism makes a living A forest is an area with a high density of Trees There are many definitions of a forest based on various criteria Grasslands (also called greenswards) are areas where the Vegetation is dominated by Grasses ( Poaceae) and other Herbaceous (non-woody Climate encompasses the temperatures humidity rainfall atmospheric particle count and numerous other meteorogical factors in a given region over long periods of

The term seed also has a general meaning that predates the above — anything that can be sown i. Sowing is the process of planting Seeds. Sowing in practice Pretreatment of seed and soil before sowing Before sowing certain seeds first require e. "seed" potatoes, "seeds" of corn or sunflower "seeds". The potato is a Starchy Tuberous crop Vegetable from the perennial Solanum tuberosum of the Solanaceae Maize (ˈmeɪz ( Zea mays L. ssp mays) known as corn in some countries is a cereal grain domesticated in Mesoamerica The sunflower seed is the Fruit of the Sunflower ( Helianthus annuus) In the case of sunflower and corn "seeds", what is sown is the seed enclosed in a shell or hull, and the potato is a tuber. The sunflower ( Helianthus annuus) is an Annual plant in the family Asteraceae and native to the Americas, with a large flowering

Contents 1 Seed structure 2 Seed production 2.1 Kinds of seeds 2.2 Seed development 2.3 Seed size and seed set 3 Seed functions 3.1 Embryo nourishment 3.2 Seed dispersal 3.2.1 By wind (anemochory) 3.2.2 By water (hydrochory) 3.2.3 By animals (zoochory) 3.3 Seed dormancy and protection 4 Seed germination 4.1 Inducing germination 5 Origin and evolution 6 Economic importance 6.1 Edible seeds 6.2 Poison and food safety 6.3 Other uses 7 Trivia 8 See also 9 References 10 External links

Seed structure

A typical seed includes three basic parts: (1) an embryo, (2) a supply of nutrients for the embryo, and (3) a seed coat. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular

The embryo is an immature plant from which a new plant will grow under proper conditions. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular Plants are living Organisms belonging to the kingdom Plantae. The embryo has one cotyledon or seed leaf in monocotyledons, two cotyledons in almost all dicotyledons and two or more in gymnosperms. A cotyledon ("seed leaf" from Greek: κοτυληδών kotylēdōn, from κοτύλη ''kotýlē'', "cup bowl" Monocotyledons or monocots are one of two major groups of Flowering plants (angiosperms that are traditionally recognised the other being Dicotyledons Dicotyledons, or "dicots", is a name for a group of Flowering plants whose Seed typically has two embryonic leaves or Cotyledons There The radicle is the embryonic root. In Botany, the radicle is the first part of a Seedling (a growing plant Embryo) to emerge from the Seed during the process of The plumule is the embryonic shoot. The embryonic stem above the point of attachment of the cotyledon(s) is the epicotyl. In Plant physiology, the epicotyl is the embryonic shoot above the Cotyledons In most plants the epicotyl will eventually develop into the stem and the leaves The embryonic stem below the point of attachment is the hypocotyl. Hypocotyl is a botanical term for a part of a germinating seedling of a Seed Plant.

Within the seed, there usually is a store of nutrients for the seedling that will grow from the embryo. A nutrient is food or chemicals that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment A seedling is a young plant Sporophyte developing out of a plant embryo from a Seed. The form of the stored nutrition varies depending on the kind of plant. In angiosperms, the stored food begins as a tissue called the endosperm, which is derived from the parent plant via double fertilization. Endosperm is the tissue produced in the Seeds of most Flowering plants around the time of fertilization For soil improvement see Fertilization (soil. The usually triploid endosperm is rich in oil or starch and protein. Starch, CAS # 9005-25-8 Chemical formula (C6H10O5n is a Polysaccharide Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl In gymnosperms, such as conifers, the food storage tissue is part of the female gametophyte, a haploid tissue. In some species, the embryo is embedded in the endosperm or female gametophyte, which the seedling will use upon germination. Germination is the process whereby growth emerges from a period of dormancy In others, the endosperm is absorbed by the embryo as the latter grows within the developing seed, and the cotyledons of the embryo become filled with this stored food. At maturity, seeds of these species have no endosperm and are termed exalbuminous seeds. Some exalbuminous seeds are bean, pea, oak, walnut, squash, sunflower, and radish. Bean is a common name for large plant Seeds of several genera of the family Fabaceae (formerly Leguminosae used for human food or animal A pea (inaccurately called a '''sweet pea''' by food distubutors is most commonly the small spherical Seed or the seed-pod of the Legume Pisum The term oak can be used as part of the common name of any of about 400 species of Trees and Shrubs in the Genus Quercus (from Latin Walnuts (genus Juglans) are Plants in the family Juglandaceae. Squashes generally refer to four species of the genus Cucurbita native to the Mexico and Central America, also called marrows depending The sunflower ( Helianthus annuus) is an Annual plant in the family Asteraceae and native to the Americas, with a large flowering The radish ( Raphanus sativus) is an edible Root vegetable of the Brassicaceae family that was domesticated in Europe in pre- Seeds with an endosperm at maturity are termed albuminous seeds. Most monocots (e. g. grasses and palms) and many dicots (e. Poaceae or Gramineae is a family in the Class Liliopsida of the flowering plants. Arecaceae or Palmae (also known by the name Palmaceae, which is taxonomically invalid or commonly palm tree) the palm family is a family of Flowering g. brazil nut and castor bean) have albuminous seeds. The Brazil nut ( Bertholletia excelsa) is a South American Tree in the family Lecythidaceae, and also the name of the tree's commercially The castor oil plant, Ricinus communis, is a Plant Species of the Euphorbiaceae (the evolution of this plant family is relatively unexplored All gymnosperm seeds are albuminous.

The seed coat (or testa) develops from the tissue, the integument, originally surrounding the ovule. The seed coat in the mature seed can be a paper-thin layer (e. g. peanut) or something more substantial (e. The peanut, or Groundnut ( Arachis hypogaea) is a species in the Legume family Fabaceae native to South America, Mexico g. thick and hard in honey locust and coconut). The Honey locust ( Gleditsia triacanthos) is a Deciduous Tree native to eastern North America and can also be found in central and southern The Coconut Palm ( Cocos nucifera) is a member of the Family Arecaceae (palm family The seed coat helps protect the embryo from mechanical injury and from drying out.

In addition to the three basic seed parts, some seeds have an appendage on the seed coat such an aril (as in yew and nutmeg) or an elaiosome (as in Corydalis) or hairs (as in cotton). Distinguish from Aryl, which is a type of organic chemical radical Taxus is a Genus of yews small coniferous Trees or Shrubs in the yew family Taxaceae. The nutmegs Myristica are a Genus of Evergreen Trees indigenous to tropical southeast Asia and Australasia Elaiosomes (elaios- oil some- body are fleshy structures that are attached to the Seeds of many Plant species Corydalis is a genus of about 300 species of annual and perennial Herbaceous Flowering plants in the family Fumariaceae, native to the Cotton is a soft staple Fibre that grows around the seeds of the cotton plant ( Gossypium sp There may also be a scar on the seed coat, called the hilum; it is where the seed was attached to the ovary wall by the funiculus. Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells

Seed production

Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms ("enclosed seeds") from the gymnosperms ("naked seeds"). The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group Gymnosperm (Gymnospermae are a group of Spermatophyte seed-bearing Plants with Ovules on the edge or blade of an open Sporophyll, which are Angiosperm seeds are produced in a hard or fleshy (or with layers of both) structure called a fruit that encloses the seeds, hence the name. The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones. However, the seeds do become covered by the cone scales as they develop in some species of conifer. A cone (in formal botanical usage Strobilus, plural strobili is an organ on Plants in the division Pinophyta ( Conifers

Kinds of seeds

There are a number of modifications to seeds by different groups of plants. One example is that of the so-called stone fruits (such as the peach), where a hardened fruit layer ( the endocarp) surrounds the actual seed and is fused to it. In Botany, a drupe is a Fruit in which an outer fleshy part ( Exocarp, or skin and Mesocarp, or flesh surrounds a shell (the pit The peach ( Prunus persica) is a species of Prunus native to China that bears an edible juicy fruit also called a peach

Many structures commonly referred to as "seeds" are actually dry fruits. The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. Sunflower seeds are sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. The sunflower ( Helianthus annuus) is an Annual plant in the family Asteraceae and native to the Americas, with a large flowering

Seed development

The seed, which is an embryo with two points of growth (one of which forms the stems the other the roots) is enclosed in a seed coat with some food reserves. Angiosperm seeds consist of three genetically distinct constituents: (1) the embryo formed from the zygote, (2) the endosperm, which is normally triploid, (3) the seed coat from tissue derived from the maternal tissue of the ovule. In angiosperms, the process of seed development begins with double fertilization and involves the fusion of the egg and sperm nuclei into a zygote. For soil improvement see Fertilization (soil. The second part of this process is the fusion of the polar nuclei with a second sperm cell nucleus, thus forming a primary endosperm. Endosperm is the tissue produced in the Seeds of most Flowering plants around the time of fertilization Right after fertilization the zygote is mostly inactive but the primary endosperm divides rapidly to form the endosperm tissue. This tissue becomes the food that the young plant will consume until the roots have developed after germination or it develops into a hard seed coat. The seed coat forms from the two integuments or outer layers of cells of the ovule, which derive from tissue from the mother plant, the inner integument forms the tegmen and the outer forms the testa. A tegmen (pl tegmina) designates the modified leathery front wing on an insect When the seed coat forms from only one layer it is also called the testa, though not all such testa are homologous from one species to the next.

In gymnosperms, the two sperm cells transferred from the pollen do not develop seed by double fertilization but instead only one sperm fertilizes the egg while the other is not used. The seed is composed of the embryo (the result of fertilization) and tissue from the mother plant, which also form a cone around the seed in coniferous plants like Pine and Spruce. This article is about the tree For other uses of the term "pine" see Pine (disambiguation. Spruce refers to Trees of the genus Picea, a genus of about 35 species of Coniferous Evergreen trees in the Family Pinaceae

The ovules after fertilization develop into the seeds; the main parts of the ovule are the funicle; which attaches the ovule to the placenta, the nucellus; the main region of the ovule were the embryo sac develops, the micropyle; A small pore or opening in the ovule where the pollen tube usually enters during the process of fertilization, and the chalaza; the base of the ovule opposite the micropyle, where integument and nucellus are joined together. Antennae (singular antenna) are paired Appendages connected to the front-most segments of Arthropods In Crustaceans they are Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells The chalaza (from Greek - khalaze - meaning "hailstone" is a structure inside animal eggs and plant Ovules It attaches or suspends the Yolk ^[1]

The shape of the ovules as they develop often affects the finale shape of the seeds. Plants generally produce ovules of four shapes: the most common shape is called anatropous, with a curved shape. Orthotropous ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. Campylotropous ovules have a curved embryo sac often giving the seed a tight “c” shape. The last ovule shape is called amphitropous, where the ovule is partly inverted and turned back 90 degrees on its stalk or funicle.

In the majority of flowering plants the zygotes first division is transversely orientated in regards to the long axis and this establishes the polarity of the embryo. The upper or chalazal pole becomes the main area of growth of the embryo, while the lower or micropylar pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufacturers nutrients from the endosperm that are utilized during the embryos growth. ^[2]

The embryo is composed of different parts; the epicotyle will grow into the shoot, the radicle grows into the primary root, the hypocotyl connects the epicotyle and the radicle, the cotyledons form the seed leaves, the testa or seed coat forms the outer covering of the seed. Monocotyledonous plants like corn, have other structures; instead of the hypocotyle-epicotyle, it has a coleoptile that forms the first leaf and connects to the coleorhiza that connects to the primary root and adventitious roots form from the sides. The seeds of corn are constructed with these structures; pericarp, scutellum (single large cotyledon) that absorbs nutrients from the endosperm, endosperm, plumule, radicle, coleoptile and coleorhiza - these last two structures are sheath-like and enclose the plumule and radicle, acting as a protective covering. The testa or seed coats of both monocots and dicots are often marked with patterns and textured markings, or have wings or tufts of hair.

Seed size and seed set

Seeds are very diverse in size. The dust-like orchid seeds are the smallest with about one million seeds per gram. Embryotic seeds have immature embryos and no significant energy reserves. They are myco-heterotrophs, depending on mycorrhizal fungi for nutrition during germination and the early growth of the seedling, in fact some terrestrial Orchid seedlings spend the first few years of their life deriving energy from the fungus and do not produce green leaves. Myco-heterotrophy is a Symbiotic relationship between certain kinds of Plants and Fungi, in which the plant gets all or part of its food from A mycorrhiza (Greek for fungus roots coined by Frank 1885 typically seen in the plural forms mycorrhizae or mycorrhizas) is a symbiotic (occasionally ^[3] At over 20 kg, the largest seed is the coco de mer. " Sea coconut " redirects here Sea coconut may also refer to the fruit of the Asian palmyra palm The coco de mer ( Lodoicea maldivica Plants that produce smaller seeds can generate many more seeds while plants with larger seeds invest more resources into those seeds and normally produce fewer seeds. Small seeds are quicker to ripen and can be dispersed sooner, so fall blooming plants often have small seeds. Many annual plants produce great quantities of smaller seeds; this helps to ensure that at least a few will end in a favorable place for growth. Herbaceous perennials and woody plants often have larger seeds, they can produce seeds over many years, and larger seeds have more energy reserves for germination and seedling growth and produce larger, more established seedlings.

Seed functions

Seeds serve several functions for the plants that produce them. Key among these functions are nourishment of the embryo, dispersal to a new location, and dormancy during unfavorable conditions. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular Biological dispersal refers to those processes by which a Species maintains ecosystem Dormancy is a period in an organism's life cycle when growth development and (in animals physical activity is temporarily suspended Seeds fundamentally are a means of reproduction and most seeds are the product of sexual reproduction which produces a remixing of genetic material and phenotype variability that natural selection acts on. The Evolution of sexual reproduction is a major puzzle The first Fossilized evidence of sexually reproducing Organisms is from Eukaryotes of the Stenian A phenotype is any observable characteristic of an Organism, such as its morphology, Development, biochemical or physiological properties Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of

Embryo nourishment

Seeds protect and nourish the embryo or baby plant. Seeds usually give a seedling a faster start than a sporling from a spore gets because of the larger food reserves in the seed.

Seed dispersal

Main article: Biological dispersal

Unlike animals, plants are limited in their ability to seek out favorable conditions for life and growth. Biological dispersal refers to those processes by which a Species maintains ecosystem As a consequence, plants have evolved many ways to disperse their offspring by dispersing their seeds (see also vegetative reproduction). Biological dispersal refers to those processes by which a Species maintains ecosystem Vegetative reproduction is a type of Asexual reproduction found in plants and is also called vegetative propagation or vegetative multiplication. A seed must somehow "arrive" at a location and be there at a time favorable for germination and growth. When the fruits open and release their seeds in a regular way, it is called dehiscent, which is often distinctive for related groups of plants, these fruits include; Capsules, follicles, legumes, silicles and siliques. When fruits do not open and release their seeds in a regular fashion they are called indehiscent, which include these fruits; Achenes, caryopsis, nuts, samaras, and utricles. ^[4]

Seed dispersal is seen most obviously in fruits; however many seeds aid in their own dispersal. Some kinds of seeds are dispersed while still inside a fruit or cone, which later opens or disintegrates to release the seeds. The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. A cone (in formal botanical usage Strobilus, plural strobili is an organ on Plants in the division Pinophyta ( Conifers Other seeds are expelled or released from the fruit prior to dispersal. For example, milkweeds produce a fruit type, known as a follicle,^[5] that splits open along one side to release the seeds. In botany a follicle is a dry unilocular many-seeded Fruit formed from one carpel and dehiscing by the ventral suture in order to release seeds such as in Larkspur Iris capsules split into three "valves" to release their seeds. In Botany a capsule is a type of simple dry Fruit produced by many species of Flowering plants A capsule is a dehiscent structure composed of two ^[6]

By wind (anemochory)

• Many seeds (e. g. maple, pine) have a wing that aids in wind dispersal. Acer ( maple) is a Genus of Trees or Shrubs They are variously classified in a family of their own the Aceraceae, or This article is about the tree For other uses of the term "pine" see Pine (disambiguation.
• The dustlike seeds of orchids are carried efficiently by the wind.
• Some seeds, (e. g. dandelion, milkweed, poplar) have hairs that aid in wind dispersal. Populus is a genus of between 25–35 species of Flowering plants in the family Salicaceae, native to most of the Northern Hemisphere.

By water (hydrochory)

• Some plants, such as Mucuna and Dioclea, produce buoyant seeds termed sea-beans or drift seeds because they float in rivers to the oceans and wash up on beaches. Biological dispersal refers to those processes by which a Species maintains ecosystem Mucuna is a Genus of around 100 accepted Species of climbing Vines and Shrubs of the family Fabaceae, found Dioclea is also the Latin name of the medieval Montenegrin state and of an Illyrian city see Duklja and Doclea (city. ^[7]

By animals (zoochory)

• Seeds (burrs) with barbs or hooks (e. Biological dispersal refers to those processes by which a Species maintains ecosystem A burr is a Seed or dry Fruit in which the seeds bear hooks or teeth which attach themselves to fur or clothing of passing animals or people g. acaena, burdock, dock which attach to animal fur or feathers, and then drop off later. Acaena is a genus of about 100 species of perennial Herbs and Subshrubs in the Rosaceae, native mainly to the Southern Hemisphere Burdock is any of a group of biennial Thistles in the Genus Arctium, family Asteraceae The docks and sorrels, Genus Rumex L, are a genus of about 200 species of annual, biennial and perennial
• Seeds with a fleshy covering (e. g. apple, cherry, juniper) are eaten by animals (birds, mammals) which then disperse these seeds in their droppings. The apple is the pomaceous Fruit of the apple tree Species Malus domestica in the Rose family Rosaceae. This article is about the Cherry berry also classified as fruit for the ornamental tree See Cherry Blossom. Junipers are Coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Feces, faeces, or fæces (see spelling differences) is a waste product from an animal's digestive tract expelled through the Anus
• Seeds (nuts) which are an attractive long-term storable food resource for animals (e. Nut is a general term for the large dry oily Seeds or Fruit of some Plants. g. acorns, hazelnut, walnut); the seeds are stored some distance from the parent plant, and some escape being eaten if the animal forgets them. The acorn is the nut of the Oak tree (genera Quercus, Lithocarpus and Cyclobalanopsis, in the The hazels ( Corylus) are a genus of Deciduous Trees and large Shrubs native to the temperate northern hemisphere Walnuts (genus Juglans) are Plants in the family Juglandaceae.

Myrmecochory is the dispersal of seeds by ants. Myrmecochory is a botanical term for "seed dispersal by Ants " Ants are social Insects of the family Formicidae and along with the related families of Wasps and Bees belong to the order Foraging ants disperse seeds which have appendages called elaiosomes^[8] (e. Elaiosomes (elaios- oil some- body are fleshy structures that are attached to the Seeds of many Plant species g. bloodroot, trilliums, Acacias, and many species of Proteaceae). Bloodroot ( Sanguinaria canadensis) is a perennial, Herbaceous Flowering plant native to eastern North America from Nova Trillium is a genus of about 40-50 species of perennial herbaceous Flowering plants native to temperate regions of North America and Asia Acacia is a Genus of Shrubs and Trees belonging to the Subfamily Mimosoideae of the family Fabaceae, first Proteaceae is a family of Flowering plants. Mainly restricted to the Southern Hemisphere, it is a fairly large family with around 80 genera Elaiosomes are soft, fleshy structures that contain nutrients for animals that eat them. The ants carry such seeds back to their nest, where the elaiosomes are eaten. The remainder of the seed, which is hard and inedible to the ants, then germinates either within the nest or at a removal site where the seed has been discarded by the ants. ^[9] This dispersal relationship is an example of mutualism, since the plants depend upon the ants to disperse seeds, while the ants depend upon the plants seeds for food. Mutualism is a Biological interaction between individuals of two different Species, where both individuals derive a fitness benefit for example increased As a result, a drop in numbers of one partner can reduce success of the other. In South Africa, the Argentine ant (Linepithema humile) has invaded and displaced native species of ants. The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa The Argentine ant ( Linepithema humile, formerly Iridomyrmex humilis) is a tiny dark Ant native to northern Argentina, Uruguay Introduced species|Weed Invasive species is a phrase with several definitions Unlike the native ant species, Argentine ants do not collect the seeds of Mimetes cucullatus or eat the elaiosomes. In areas where these ants have invaded, the numbers of Mimetes seedlings have dropped. A seedling is a young plant Sporophyte developing out of a plant embryo from a Seed. ^[10]

Seed dormancy and protection

Further information: Seed hibernation

One important function of most seeds is delaying germination, which allows time for dispersal and prevents germination of all the seeds at one time when conditions appear favorable. Seed hibernation is different from seed dormancy. While seed dormancy can be defined as "a seed not germinating when conditions e The staggering of germination safeguards some seeds or seedlings from suffering during short periods of bad weather, transient herbivores or competition from other plants for light and nutrients. Many species of plants have seeds that germinate over many months or years, and some seeds can remain in the soil seed bank for more than 50 years before germination. Seed dormancy is defined as a seed failing to germinate under environmental conditions optimal for germination, normally when the seed's environment is at the right temperature with proper soil moisture conditions. Seed hibernation is different from seed dormancy. While seed dormancy can be defined as "a seed not germinating when conditions e Induced dormancy or seed quiescence occurs when a seed fails to germinate because the external environmental conditions are inappropriate for germination, mostly in response to being too cold or hot, or too dry. True dormancy or innate dormancy is caused by conditions within the seed that prevent germination under normally ideal conditions. Often seed dormancy is divided into four major categories: exogenous; endogenous; combinational; and secondary.

Exogenous dormancy is caused by conditions outside the embryo including:

• Hard seed coats or physical dormancy occurs when seeds are impermeable to water or the exchange of gases. Permeability in the Earth sciences (commonly symbolized as κ, or k) is a measure of the ability of a material (typically a rock or unconsolidated In some seeds the seed coat physically prevents the seedling from growing.
• Chemical dormancy includes growth regulators etc.

Endogenous dormancy is caused by conditions within the embryo itself, including:

• Immature embryos where some plants release their seeds before the tissues of the embryos have fully differentiated, and the seeds ripen after they take in water while on the ground, germination can be delayed from a few weeks to a few months.
• Morphological dormancy where seeds have fully differentiated embryos that need to grow more before seed germination, the embryos are not yet fully developed.
• Morphophysiological dormancy seeds with underdeveloped embryos, and in addition have physiological components to dormancy. These seeds therefore require a dormancy-breaking treatments as well as a period of time to develop fully grown embryos.
• Physiological dormancy prevents seed germination until the chemical inhibitors are broken down or are no longer produced by the seed, often physiological dormancy is broken by a period of cool moist conditions, normally below (+4C) 39F, or in the case of many species in Ranunculaceae and a few others,(-5C) 24F. Ranunculaceae is a family of Flowering plants also known as the "buttercup family" or "crowfoot family" Other chemicals that prevent germination are washed out of the seeds by rainwater or snow melt. Abscisic acid is usually the growth inhibitor in seeds and its production can be affected by light. Abscisic acid (ABA also known as abscisin II and dormin, is a Plant hormone. Some plants like Peony species have multiple types of physiological dormancy, one affects radical growth while the other affects shoot growth. For the ancient Balkan region and tribe see Paionia. The peony or paeony ( Paeonia) is the only genus in the
  • Drying; some plants including a number of grasses and those from seasonally arid regions need a period of drying before they will germinate, the seeds are released but need to have a lower moister content before germination can begin. If the seeds remain moist after dispersal, germination can be delayed for many months or even years. Many herbaceous plants from temperate climate zones have physiological dormancy that disappears with drying of the seeds. Other species will germinate after dispersal only under very narrow temperature ranges, but as the seeds dry they are able to germinate over a wider temperature range. ^[11]
  • Photodormancy or light sensitivity affects germination of some seeds. These photoblastic seeds need a period of darkness or light to germinate. In species with thin seed coats, light may be able to penetrate into the dormant embryo. Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 The presence of light or the absence of light may trigger the germination process, inhibiting germination in some seeds buried too deeply or in others not buried in the soil.
  • Thermodormancy is seed sensitivity to heat or cold. Some seeds including cocklebur and amaranth germinate only at high temperatures (30C or 86F) many plants that have seed that germinate in early to mid summer have thermodormancy and germinate only when the soil temperature is warm. Other seeds need cool soils to germinate, while others like celery are inhibited when soil temperatures are too warm. Often thermodormancy requirements disappear as the seed ages or dries.

Combinational dormancy also called double dormancy. Many seeds have more than one type of dormancy,^[12] some Iris species have both hard impermeable seeds coats and physiological dormancy.

Secondary dormancy is caused by conditions after the seed has been dispersed and occurs in some seeds when non-dormant seed is exposed to conditions that are not favorable to germination, very often high temperatures. The mechanisms of secondary dormancy are not yet fully understood but might involve the loss of sensitivity in receptors in the plasma membrane. ^[13]

Many garden plants have seeds that will germinate readily as soon as they have water and are warm enough, though their wild ancestors may have had dormancy, these cultivated plants lack seed dormancy. After many generations of selective pressure by plant breeders and gardeners dormancy has been selected out.

For annuals, seeds are a way for the species to survive dry or cold seasons. Botanically an annual plant is a Plant that usually germinates, Flowers and dies in one Year. Ephemeral plants are usually annuals that can go from seed to seed in as few as six weeks. ^[14]

Not all seeds undergo a period of dormancy. Seeds of some mangroves are viviparous, they begin to germinate while still attached to the parent. Mangroves (generally are Trees and Shrubs that grow in saline coastal habitats in the Tropics and Subtropics. The large, heavy root allows the seed to penetrate into the ground when it falls.

Seed germination

Main articles: Seedling and Germination

Seed germination is the process of growth of the embryo into a functional plant. A seedling is a young plant Sporophyte developing out of a plant embryo from a Seed. Germination is the process whereby growth emerges from a period of dormancy It involves the reactivation of the metabolic pathways that lead to growth and the emergence of the radicle or seed root and plumule or shoot.

Three fundamental conditions must exist before germination can occur. (1) The embryo must be alive, called seed viability. (2) Any dormancy requirements that prevent germination must be over come. (3) The proper environmental conditions must exist for germination.

Seed viability determines the percentage of possible seed germination and is affected by a number of different conditions. Some plants do not produce seeds that have functional complete embryos or the seed may have no embryo at all, often called empty seeds. Predators and pathogens can damage or kill the seed while it is still in the fruit or after it is dispersed. Environmental conditions like flooding or heat can kill the seed before or during germination. The age of the seed affects its health and germination ability, since the seed has a living embryo, over time cells die and cannot be replaced. Some seeds can live for a long time before germination, while others can only survive for a short period after dispersal before they die.

Seed vigor is a measure of the quality of seed, and involves the viability of the seed, the germination percentage, germination rate and the strength of the seedlings produced. ^[15]

The germination percentage is simply the proportion of seeds that germinate from all seeds subject to the right conditions for growth. The germination rate is the length of time it takes for the seeds to germinate. Germination percentages and rates are affected by seed viability, dormancy and environmental effects that impact on the seed and seedling. In agriculture and horticulture quality seeds have high viability, measured by germination percentage plus the rate of germination. This is given as a percent of germination over a certain amount of time, 90% germination in 20 days, for example. 'Dormancy' is covered above; many plants produce seeds with varying degrees of dormancy, and different seeds from the same fruit can have different degrees of dormancy. ^[16] It's possible to have seeds with no dormancy if they are dispersed right away and do not dry (if the seeds dry they go into physiological dormancy). There is great variation amongst plants and a dormant seed is still a viable seed even though the germination rate might be very low.

Environmental conditions effecting seed germination include; water, oxygen, temperature and light.

Three distinct phases of seed germination occur: water imbibition; lag phase; and radicle emergence. In Botany, the radicle is the first part of a Seedling (a growing plant Embryo) to emerge from the Seed during the process of

In order for the seed coat to split, the embryo must imbibe (soak up water), which causes it to swell, splitting the seed coat. However, the nature of the seed coat determines how rapidly water can penetrate and subsequently initiate germination. Germination is the process whereby growth emerges from a period of dormancy The rate of imbibition is dependent on the permeability of the seed coat, amount of water in the environment and the area of contact the seed has to the source of water. For some seeds, imbibing to much water to quickly can kill the seed. For some seeds, once water is imbibed the germination process can not be stopped and if the seed dries out again it is fatal. While other species have seeds that can imbibe and lose water a few times with out causing ill effects to the seed or drying can cause secondary dormancy.

Inducing germination

A number of different strategies are used by gardeners and horticulturists to break seed dormancy.

Scarification of hard seed coats involving the breaking, scratching or softening by chemicals like acids. Other means of scarification include soaking in hot water or poking holes in the seed with a pin. Sometimes fruits are harvested while the seeds are still immature and the seed coat is not fully developed and sown right away. Under natural conditions the seed coats can be broken by rodents chewing on the seeds, rubbing against rocks or freezing and thawing of surface water, battering on rocks in a stream-bed, or passing through an animal's digestive tract. In the latter case, the seed coat protects the seed from digestion, while perhaps weakening the seed coat such that the embryo is ready to sprout when it gets deposited (along with a bit of fertilizer) far from the parent plant. Digestion is the breaking down of chemicals in the body into a form that can be absorbed Microorganisms are often effective in breaking down hard seed coats and are sometimes used by people as a treatment, the seeds are stored in a moist warm sandy medium for several months under non-sterile conditions. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually

Stratification also called moist-chilling is a method to break down physiological dormancy and involves the addition of moisture to the seeds so they imbibe water and then the seeds are subject to a period of moist chilling to after-ripen the embryo. Sowing outside in late summer and fall and allowing to overwinter outside under cool conditions is an effective way to stratify seeds, some seeds respond more favorably to periods of osculating temperatures which are part of the natural environment.

Leaching or the soaking in water removes chemical inhibitors in some seeds that prevent germination. Rain and melting snow naturally accomplish this task. Rain is Liquid precipitation. On Earth it is the condensation of atmospheric Water vapor into drops heavy enough to fall often making it to "Snowfall" redirects here For other uses see Snow (disambiguation or Snowfall (disambiguation. For seeds that are going to be planted for gardens, the use of running water is best but frequent changes of water are effective too. Normally 12 to 24 hours of soaking is sufficient, longer soaking especially in stagnant water that is not changed can result in oxygen starvation and seed death. Seeds with hard seed coats can be soaked in hot water to break open the impermeable cell layers that prevent water intake.

Other methods used to assist in the germination of seeds that have dormancy include prechilling, predrying, daily alternation of temperature, light exposure, potassium nitrate, the use of plant growth regulators like gibberellins, cytokinins, ethylene, thiourea, sodium hypochlorite plus others. ^[17]

Origin and evolution

The origin of seed plants is a problem that still remains unsolved. However, more and more data tends to place this origin in the middle Devonian. The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. The description in 2004 of the proto-seed Runcaria heinzelinii in the Givetian of Belgium is an indication of that ancient origin of seed-plants. The Kingdom of Belgium is a Country in northwest Europe. It is a founding member of the European Union and hosts its headquarters as well as those As with modern ferns, most land plants before this time reproduced by sending spores into the air, that would land and become whole new plants.

The first "true" seeds are described from the upper Devonian, which is probably the theater of their true first evolutionary radiation. The seed plants progressively became one of the major elements of nearly all ecosystems.

Economic importance

Edible seeds

Further information: List of edible seeds

Many seeds are edible and the majority of human calories comes from seeds, especially from cereals, legumes and nuts. A list of edible seeds here includes seeds that are directly foodstuffs rather than yielding derived products A list of edible seeds here includes seeds that are directly foodstuffs rather than yielding derived products A legume is a Plant in the family Fabaceae (or Leguminosae or a Fruit of these specific plants Nut is a general term for the large dry oily Seeds or Fruit of some Plants. Seeds also provide most cooking oils, many beverages and spices and some important food additives. Cooking oil is purified Fat of Plant or Animal origin which is liquid at room temperature A drink, or beverage, is a Liquid specifically prepared for Human consumption A spice is a dried Seed, Fruit, Root, Bark or vegetative substance used in Nutritionally insignificant quantities as a Food additive Food additives are substances added to food to preserve flavour or improve its taste and appearance In different seeds the seed embryo or the endosperm dominates and provides most of the nutrients. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular Endosperm is the tissue produced in the Seeds of most Flowering plants around the time of fertilization A nutrient is food or chemicals that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment The storage proteins of the embryo and endosperm differ in their amino acid content and physical properties. Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this For example the gluten of wheat, important in providing the elastic property to bread dough is strictly an endosperm protein. Gluten is a composite of the proteins Gliadin and Glutenin. These exist conjoined with Starch, in the Endosperms of some A material is said to be elastic if it deforms under stress (e Dough is a paste made out of any Cereals (grains or leguminous crops by mixing the Flour with a small amount of Water.

Seeds are used to propagate many crops such as cereals, legumes, forest trees, turfgrasses and pasture grasses. Forestry is the Art and Science of managing forests tree Plantations and related Natural resources. A lawn is an area of recreational or amenity land planted with grass, and sometimes Clover and other plants which are maintained at a low even height Pasture is land with Herbaceous vegetation cover used for grazing of Ungulate Livestock as part of a Farm or Ranch.

Seeds are also eaten by animals, and are fed to livestock. Livestock is the term used to refer (singularly or plurally to a Domesticated Animal intentionally reared in an agricultural setting to produce such as Food Many seeds are used as birdseed. Bird food is Food (often varieties of Seeds eaten by Birds Humans generally make or buy bird food to feed to Pet birds or use in Birdfeeders

Poison and food safety

While some seeds are considered by some as healthy to eat, other seeds may be harmful or poisonous,^[18] Plants and seeds often contain chemical compounds to discourage herbivores and seed predators. A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Seed predation includes any process inflicted on a Plant ’s seeds by an animal that results in the inviability of the Seed. In some cases, these compounds simply taste bad (such as in mustard), but other compounds are toxic, or breakdown into toxic compounds within the digestive system. Mustard is a thick yellowish-brown paste with a sharp taste made from the ground seeds of a Mustard plant (white or yellow mustard Sinapis hirta Digestion is the breaking down of chemicals in the body into a form that can be absorbed Children, being smaller than adults, are more susceptible to poisoning or death by plants and seeds. ^[19] One should be satisfied with reliable food safety information before choosing to eat any particular seeds.

An infamously deadly poison, ricin, comes from seeds of the castor bean. Ricin (ˈraɪ sɨn is a Protein Toxin that is extracted from the castor bean ( Ricinus communis) The castor oil plant, Ricinus communis, is a Plant Species of the Euphorbiaceae (the evolution of this plant family is relatively unexplored Reported lethal doses are anywhere from two to eight seeds,^[20][21] though only a few deaths have been reported when castor beans have been ingested by animals. ^[22]

In addition, seeds containing amygdalin; apple, apricot, bitter almond,^[23] peach, plum, cherry, quince, and others, when consumed in significant amounts, may result in cyanide toxicity^[23]. Amygdalin (from Greek: grc-Latn amygdálē “almond” C20H27NO11 is a Glycoside initially isolated from the seeds The apple is the pomaceous Fruit of the apple tree Species Malus domestica in the Rose family Rosaceae. The Apricot ( Prunus armeniaca, "Armenian plum" in Latin syn The Almond ( Prunus dulcis, syn Prunus amygdalus Batsch Amygdalus communis L The peach ( Prunus persica) is a species of Prunus native to China that bears an edible juicy fruit also called a peach A plum or gage is a stone fruit Tree in the genus Prunus, subgenus Prunus. This article is about the Cherry berry also classified as fruit for the ornamental tree See Cherry Blossom. The Quince (kwɪns or Cydonia oblonga, is the sole member of the genus Cydonia and native to warm-temperate southwest Asia in the Caucasus ^[24] Other seeds than contain poisons include annona, cotton, custard apple, datura, uncooked durian, golden chain, horse-chestnut, larkspur, locoweed, lychee, nectarine, rambutan, rosary pea, sour sop, sugar apple, wisteria, and yew. For other meanings see Annona (disambiguation. Annona is the second largest Genus, after Guatteria Cotton is a soft staple Fibre that grows around the seeds of the cotton plant ( Gossypium sp Datura is a Genus of 12-15 species of vespertine Flowering plants belonging to the family Solanaceae. The durian ( is the Fruit of trees from the Genus Durio belonging to the "Indian laburnum" is the Golden Shower Tree, a distant relative of the genus Laburnum For the South African Thoroughbred racehorse see Horse Chestnut (horse. Delphinium is a Genus of about 250 Species of annual biennial or perennial Flowering plants in the buttercup family Ranunculaceae, Locoweed is also a slang name for Cannabis, and Jimson weed. Locoweed is a term used to describe Plants from two different The Lychee ( Litchi chinensis) also spelled Litchi (the US FDA spelling or Laichi and Lichu, Chinese: 荔枝 The peach ( Prunus persica) is a species of Prunus native to China that bears an edible juicy fruit also called a peach The rambutan (ramˈbut̪ɑn Nephelium lappaceum) is a medium-sized tropical Tree in the family Sapindaceae, and the fruit of this tree The soursop ( Spanish guanábana, Portuguese graviola) Annona muricata; Syn Annona squamosa (also called Sugar-apple, or Sweetsop) is a species of Annona native to the tropical Americas Wisteria is a Genus of about ten species of woody climbing Vines native to the eastern United States and the East Asian states of China Taxus is a Genus of yews small coniferous Trees or Shrubs in the yew family Taxaceae. ^[25][26] Another seed poison is strychnine. Strychnine (ˈstrɪkniːn (British US /-naɪn/ or /-nɪn/ (US

The seeds of many legumes, including the common bean (Phaseolus vulgaris) contain proteins called lectins which can cause gastric distress if the beans are eaten without cooking. Lectins are sugar-binding Proteins which are highly specific for their sugar Moieties. Cooking is the process of preparing Food by applying Heat, selecting measuring and combining of ingredients in an ordered procedure for producing safe and edible The common bean and many others, including the soybean, also contain trypsin inhibitors which interfere with the action of the digestive enzyme trypsin. Trypsin inhibitors are chemicals that reduce the availability of Trypsin, an Enzyme essential to Nutrition of many Animals including Humans Trypsin ( is a Serine protease found in the Digestive system, where it breaks down Proteins Trypsin predominantly cleaves peptide chains at the carboxyl Normal cooking processes degrade lectins and trypsin inhibitors to harmless forms. ^[27]

Other uses

The world's most important clothing fiber grows attached to cotton seed. Fiber or fibre is a class of Materials that are continuous filaments or are in discrete elongated pieces similar to lengths of thread. Cotton is a soft staple Fibre that grows around the seeds of the cotton plant ( Gossypium sp Other seed fibers are from kapok and milkweed. For the children's book see The Great Kapok Tree. Kapok ( Ceiba pentandra) is a tropical Tree of the order

Many important nonfood oils are extracted from seeds. Linseed oil is used in paints. Linseed oil, also known as flax seed oil or simply flax oil, is a clear to yellowish Drying oil derived from the dried ripe seeds of the Flax Oil from jojoba and crambe are similar to whale oil. Jojoba ( Simmondsia chinensis) pronounced "hō- hō' -bə" is a Shrub native to the Sonoran and Mojave Deserts See also Crambe North Yorkshire Crambe is a Genus of Brassicaceae native to Europe, southwest Whale oil is the oil obtained from the Blubber of various species of Whales particularly the three species of Right Whale ( Eubalaena japonica

Seeds are the source of some medicines including castor oil, tea tree oil and the discredited cancer drug, Laetrile. Castor oil is a Vegetable oil obtained from the Castor bean (technically castor seed as the castor plant Ricinus communis, is not a member of Tea tree oil is an extraction from the Melaleuca tree Tea tree oil or melaleuca oil is a clear to very pale golden color Essential oil Amygdalin (from Greek: grc-Latn amygdálē “almond” C20H27NO11 is a Glycoside initially isolated from the seeds

Many seeds have been used as beads in necklaces and rosaries including Job's tears, Chinaberry and rosary pea. A bead is a small decorative object that is pierced for threading or stringing Job 's Tears ( Coix lacryma-jobi) Coixseed, adlay, or adlai, is a tall grain-bearing Tropical Plant of the Commonly called Persian Lilac, White Cedar, Chinaberry or Bead Tree, Melia azedarach ( syn However, the latter two are also poisonous.

Other seed uses include:

• Seeds once used as weights for balances. A weighing scale (usually just "scale" in common usage except in Australian English where "scales" is more common is a Measuring instrument for
• Seeds used as toys by children, such as for the game conker.
• Resin from Clusia rosea seeds used to caulk boats. Clusia is the Type genus of the family Clusiaceae. Comprising 140-150 species it is native to tropical and subtropical America
• Nematicide from milkweed seeds. A nematicide is a type of Chemical Pesticide used to kill Parasitic Nematodes (roundworms
• Cottonseed meal used as animal feed and fertilizer. Cottonseed meal is the Byproduct remaining after Cotton is ginned and the seeds crushed and the oil extracted Fertilizers ( also spelt fertiliser are chemical compounds given to Plants to promote growth they are usually applied either through the soil for uptake by plant

Trivia

• The oldest viable carbon-14-dated seed that has grown into a plant was a Judean date palm seed about 2,000 years old, recovered from excavations at Herod the Great's palace on Masada in Israel. There are several candidates for the oldest viable seed Carbon dated The oldest Carbon-14 -dated seed that has grown into a viable plant was a Judean date Carbon-14, 14C, or radiocarbon, is a Radioactive isotope of Carbon discovered on February 27, 1940, by The Judean date palm is a Cultivar of the Date palm ( Phoenix dactylifera) Herod (הוֹרְדוֹס Horodos, Greek: Herōdes) also known as Herod I or Herod the Great (73 BC – 4 BC in Jericho Masada ( Hebrew מצדה pronounced Metzada, from מצודה metzuda, "fortress" is the name for a site of ancient Palaces and For a topic outline on this subject see List of basic Israel topics. It was germinated in 2005. ^[28]

• The largest seed is produced by the coco de mer, or "double coconut palm", Lodoicea maldivica. " Sea coconut " redirects here Sea coconut may also refer to the fruit of the Asian palmyra palm The coco de mer ( Lodoicea maldivica The entire fruit may weigh up to 23 kilograms (50 pounds) and usually contains a single seed. The term fruit has different meanings dependent on context and the term is not synonymous in Food preparation and Biology. ^[29]

• The earliest fossil seeds are around 365 million years old from the Late Devonian of West Virginia. FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. The Devonian is a geologic period and system of the Paleozoic era spanning from to  million years ago. West Virginia ( is a state in the Appalachian Upland South, and Mid-Atlantic regions of the United States, bordered by The seeds are preserved immature ovules of the plant Elkinsia polymorpha. Ovule literally means "small egg." In Seed plants the ovule is the structure that gives rise to and contains the female reproductive cells Plants are living Organisms belonging to the kingdom Plantae. ^[30]

See also

• Biological dispersal
• Germination
• List of edible seeds
• Recalcitrant seed
• Seed company
• Seed orchard
• Seed predation
• Seedbed
• Seedling
• Stratification

References

External links

• List of Common Botanical Seed Names
• The Seed Site: collecting, storing, sowing, germinating, and exchanging seeds, with pictures of seeds, seedpods and seedlings.
• The Seed Biology Place seed structure, dormany, evolution, ecology, etc.
• Flavon's Secret Flower Garden - Pictures of Japanese plant seeds, fruits and etc.
• The Millennium Seed Bank Project Kew Garden's ambitious preservation project
• The Svalbard Global Seed Vault - a backup facility for the world's seed banks

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