Seed

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4. Questions - Got a question about Seed then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

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6. Returns - still worried that even after all of the above your Seed wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

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9. Contact - got a question about Seed, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Seed, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

cut open to show the seedsA seed is a small Plant embryogenesis plant enclosed in a covering called the seed coat, usually with some Food storage. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant. 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.

Seeds have been an important development in the reproduction and spread of flowering plants, relative to more primitive plants like mosses, ferns and marchantiophytas, which do not have seeds and use other means to propagate themselves. This can be seen by the success of seed plants (both gymnosperms and angiosperms) in dominating biological Ecological niches on land, from forests to grasslands both in hot and cold climates.

Seed also has a general meaning that predates the above - anything that can be Sowing i.e. "seed" potatoes, "seeds" of maize or sunflower seed. 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.

Seed structure seed. (a) seed coat, (b) endosperm, (c) cotyledon, (d) hypocotyl.A typical seed includes three basic parts: (1) an embryo, (2) a supply of nutrients for the embryo, and (3) a seed coat.

The embryo is an immature plant from which a new plant will grow under proper conditions. The embryo has one cotyledon or seed leaf in monocotyledons, two cotyledons in almost all dicotyledons and two or more in gymnosperms. The radicle is the embryonic root. The plumule is the embryonic shoot. The embryonic stem above the point of attachment of the cotyledon(s) is the epicotyl. The embryonic stem below the point of attachment is the hypocotyl.

Within the seed, there usually is a store of nutrients for the seedling that will grow from the embryo. 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. The usually triploid endosperm is rich in Vegetable oil or starch and protein. In gymnosperms, such as Pinophytas, 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. 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 (vegetable), sunflower, and radish. Seeds with an endosperm at maturity are termed albuminous seeds. Most monocots (e.g. Poaceae and Arecaceae) and many dicots (e.g. brazil nut and castor bean) have albuminous seeds. 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.g. thick and hard in honey locust and coconut). 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). 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 ovule.

Seed production seeds.Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms ("enclosed seeds") from the gymnosperms ("naked seeds"). 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. 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 Conifer cone scales as they develop in some species of conifer.

Kinds of seeds There are a number of modifications to seeds by different groups of plants. One example is that of the so-called Drupe fruits (such as the peach), where a hardened fruit layer ( the endocarp) surrounds the actual seed and is fused to it.

Many structures commonly referred to as "seeds" are actually dry fruits. Sunflower seeds are sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed.

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. The second part of this process is the fusion of the polar nuclei with a second sperm cell nucleus, thus forming a primary endosperm. 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. 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.

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.Kigel, Jaime, and Gad Galili. 1995. Seed development and germination. Books in soils, plants, and the environment. New York: M. Dekker.ISBN 0824792297. Chapter one.

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.Raven, Peter H., Ray Franklin Evert, and Helena Curtis. 1981. Biology of plants. New York, N.Y.: Worth Publishers. page 410.

The embryo is made up of different parts, the epicotyle will grow into the shoot, the radicle with grow 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. The monocotyledonous corn plant has 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) it 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 coat of both monocots and dicots is often marked with patterns and textured markings, or it can 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-heterotrophy, 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.Smith, Welby R. 1993. Orchids of Minnesota. Minneapolis: University of Minnesota Press. Page 8. At over 20 kg, the largest seed is the coco de mer. 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, biological dispersal to a new location, and dormancy during unfavorable conditions. 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.

Seed dispersal Unlike animals, plants are limited in their ability to seek out favorable conditions for life and growth. As a consequence, plants have evolved many ways to Biological dispersal their offspring by dispersing their seeds (see also vegetative reproduction). 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, including these types of fruits; Achenes, caryopsis, nuts, samaras, and utricles.Jones, Samuel B., and Arlene E. Luchsinger. 1979. Plant systematics. McGraw-Hill series in organismic biology. New York: McGraw-Hill. Page 195.

Often, seed dispersal is attributed mainly to fruits, however many seeds aid in their own dispersal. Some kinds of seeds are dispersed while still inside a fruit or conifer cone, which later opens or disintegrates to release the seeds. Other seeds are expelled or released from the fruit prior to dispersal. For example, milkweeds produce a fruit type, known as a Follicle (fruit),{{cite book| last= Cronquist| first= Arthur| year=1981| title=An Integrated System of Classification of Flowering Plants| pages=882| location= New York| publisher= Columbia University Press| id=ISBN 0-231-03880-1 --> that splits open along one side to release the seeds. Iris (plant) Capsule (fruit) split into three "valves" to release their seeds.{{cite book| last= Stern| first= Kingsley R.| year=1991| title=Introductory Plant Biology| edition = 5th| pages=131| location= Dubuque, IA| publisher= Wm. C. Brown Publishers| id=ISBN 0-697-09947-4 -->

By wind image:Photos-photos_1088103921_Floating.jpgs) can be carried long distances by the wind.

Many seeds (e.g. maple, pine) have a wing that aids in wind dispersal.
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.

By water

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 http://www.seabean.com/.

By animals

Seeds (burr (fruit)s) with barbs or hooks (e.g. acaena, burdock, Rumex which attach to animal fur or feathers, and then drop off later.
Seeds with a fleshy covering (e.g. apple, cherry, juniper) are eaten by animals (birds, mammals) which then disperse these seeds in their faeces.
Seeds (nut (fruit)) which are an attractive long-term storable food resource for animals (e.g. acorns, hazelnut, walnut); the seeds are stored some distance from the parent plant, and some escape being eaten if the animal stores hold them.

Myrmecochory is the dispersal of seeds by ants. Foraging ants disperse seeds which have appendages called elaiosomesMarinelli, J. (1999) "Ants - The astonishing intimacy between ants & plants." Plants & Gardens News 14 (1). (e.g. bloodroot, trilliums, Acacias, and many species of Proteaceae). 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.Ricklefs, Robert E. (1993) The Economy of Nature, 3rd ed., p.396. (New York: W. H. Freeman). ISBN 0-7167-2409-X. 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. 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 invasive species and displaced native species of ants. 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.

Seed dormancy and protection 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. 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 seeds environment is at the right temperature with proper soil moisture conditions. 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. Factors causing dormancy include:

Hard seed coats or physical dormancy results from seeds that are impermeable to water or the exchange of gases. In some the seed coats physically prevents the seedling from growing.
Immature embryos were 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 were seeds are have fully differentiated embryos that need to yet 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.
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. The seeds need to dry first then take in water before germination begins, if the seeds take in water right after being released they will not germinate.
Light sensitivity or 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. 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.
Physiological dormancy prevents seed germinations 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. 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.
Combinational dormancy Many seeds have more than one type of dormancy,http://www.seedbiology.de/dormancy.asp some Iris species have both hard impermeable seeds coats and Physiological dormancy, other seeds like Peony species have multiply types of physiological dormancy

A number of different strategies are used by gardeners and horticulturists to break seed dormancy including 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. Some times 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. 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.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 over winter outside under cool conditions is an effect 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. Running water is best but frequent changes of water are effective too. Normally 12 to 24 hours or 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.Hartmann, Hudson Thomas, and Dale E. Kester. 1983. Plant propagation principles and practices. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0136810071. Pages 175-77.

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 annual plant, seeds are a way for the species to survive dry or cold seasons. Ephemeral plants are usually annuals that can go from seed to seed in as few as six weeks.Patten, D.T. 1978. Productivity and production efficiency of an Upper Sonoran Desert ephemeral community. American Journal of Botany 65: 891-895.

Not all seeds undergo a period of dormancy. Seeds of some mangroves are viviparous, they begin to germinate while still attached to the parent. The large, heavy root allows the seed to penetrate into the ground when it falls.

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 germination 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.

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 description in 2004 of the proto-seed Runcaria heinzelinii in the Givetian of Belgium is an indication of that ancient origin of seed-plants. As with modern ferns, most land plants before this time reproduced by sending spoor 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 seeds.

Edible seeds Many seeds are List of edible seeds (such as grape, pumpkin, and sunflower seed) and are considered by some as healthy to eat. The majority of human calories comes from seeds, especially from cereals, legumes and Nut (fruit)s. Seeds also provide most cooking oils, many beverages and spices and some important food additives.

Seeds are used to propagate many crops such as cereals, legumes, forestry, turfgrasses and pasture grasses.

Seeds are also eaten by animals, and are fed to livestock. Many seeds are used as birdseed.

Poison and food safety While some seeds are considered by some as healthy to eat, other seeds may be harmful or poisonous,Chia Joo Suan, " Seeds of Doubt: Food Safety" Plants and seeds often contain chemical compounds to discourage herbivores and seed predation. 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. Children, being smaller than adults, are more susceptible to poisoning or death by plants and seeds.Clelland, Mike. " Poisonous Plants and Seeds", Healthy Child Care 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. Reported lethal doses are anywhere from two to eight seeds,though only a few deaths have been reported when castor beans have been ingested by animals.http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=10825094&ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVAbstractPlus

In addition, seeds containing amygdalin; apple, apricot, bitter almond, peach, plum, quince, and others, when consumed in significant amounts, may result in cyanide toxicity, though its not likely that enough could be eaten to cause serous harm to most healthy people.http://www.washingtonpost.com/wp-dyn/articles/A46703-2005Jan4.htmlOther seeds than contain poisons include annona, cherry, cotton, custard apple, datura, uncooked durian, golden chain, Horse-chestnut (tree), larkspur, locoweed, lychee, nectarine, rambutan, rosary pea, sour sop, sugar apple, wisteria, and yew. Another seed poison is strychnine.

Other uses (in bottles) and coconut oil (in jars in the middle).The world's most important clothing fiber grows attached to cotton seed. Other seed fibers are from kapok and milkweed.

Many important nonfood oils are extracted from seeds. Linseed oil is used in paints. Oil from jojoba and crambe are similar to whale oil.

Seeds are the source of some medicines including castor oil, tea tree oil and the discredited cancer drug, Amygdalin.

Many seeds have been used as beads in necklaces and rosaries including Job's tears, Chinaberry and Abrus precatorius. However, the latter two are also poisonous.

Other seed uses include:

Seeds once used as weights for Weighing scales.
Seeds used as toys by children, such as for the game conker.
Resin from Clusia rosea seeds used to caulk boats.
Nematicide from milkweed seeds.
Cottonseed meal used as animal feed and fertilizer.

Trivia of the coco de mer.

The Oldest viable seed 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. It was germinated in 2005. Roach, John. (2005) " 2,000-Year-Old Seed Sprouts, Sapling Is Thriving", National Geographic News, 22 November.

The largest seed is produced by the coco de mer, or "double coconut palm", Lodoicea maldivica. The entire fruit may weigh up to 23 kilograms (50 pounds) and usually contains a single seed.Corner, E. J. H. (1966) The Natural History of Palms, p313-314. (Berkeley, CA: University of California Press).

The earliest fossil seeds are around 365 million years old from the Famennian Devonian of West Virginia. The seeds are preserved immature ovules of the plant Elkinsia polymorpha.Taylor, Thomas N. & Edith L. Taylor. 1993 The Biology and Evolution of Fossil Plants, page 466. (Englewood Cliffs, NJ: Prentice Hall). ISBN 0-13-651589-4.