Seeds

A seed is a small <a href="http://en.wikipedia.org/wiki/Plant_embryogenesis" title="Plant embryogenesis" >embryonic</a> <a href="http://en.wikipedia.org/wiki/Plant" title="Plant" >plant</a> enclosed in a covering called the seed coat, usually with some <a href="http://en.wikipedia.org/wiki/Food_storage" title="Food storage" >stored food</a>. It is the product of the ripened <a href="http://en.wikipedia.org/wiki/Ovule" title="Ovule" >ovule</a> of <a href="http://en.wikipedia.org/wiki/Gymnosperm" title="Gymnosperm" >gymnosperm</a> and <a href="http://en.wikipedia.org/wiki/Angiosperm" title="Angiosperm" class="mw-redirect" >angiosperm</a> plants which occurs after <a href="http://en.wikipedia.org/wiki/Fertilization" title="Fertilization" class="mw-redirect" >fertilization</a> and some growth within the mother plant.

The formation of the seed completes the process of <a href="http://en.wikipedia.org/wiki/Reproduction" title="Reproduction" >reproduction</a> in seed plants (started with the development of <a href="http://en.wikipedia.org/wiki/Flower" title="Flower" >flowers</a>and <a href="http://en.wikipedia.org/wiki/Pollination" title="Pollination" >pollination</a>), with the <a href="http://en.wikipedia.org/wiki/Embryo" title="Embryo" >embryo</a> developed from the <a href="http://en.wikipedia.org/wiki/Zygote" title="Zygote" >zygote</a> and the seed coat from the integuments of the ovule.

Seeds have been an important development in the reproduction and spread of <a href="http://en.wikipedia.org/wiki/Flowering_plants" title="Flowering plants" class="mw-redirect" >flowering plants</a>, relative to more primitive plants

such as <a href="http://en.wikipedia.org/wiki/Moss" title="Moss" >mosses</a>, <a href="http://en.wikipedia.org/wiki/Fern" title="Fern" >ferns</a> and <a href="http://en.wikipedia.org/wiki/Marchantiophyta" title="Marchantiophyta" >liverworts</a>, 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 <a href="http://en.wikipedia.org/wiki/Ecological_niche" title="Ecological niche" >niches</a> on land, from <a href="http://en.wikipedia.org/wiki/Forest" title="Forest" >forests</a> to <a href="http://en.wikipedia.org/wiki/Grassland" title="Grassland" >grasslands</a> both in hot and cold <a href="http://en.wikipedia.org/wiki/Climates" title="Climates" class="mw-redirect" >climates</a>.

The term "seed" also has a general meaning that antedates the above — anything that can be <a href="http://en.wikipedia.org/wiki/Sowing" title="Sowing" >sown</a>, e.g. "seed" <a href="http://en.wikipedia.org/wiki/Potato" title="Potato" >potatoes</a>, "seeds" of <a href="http://en.wikipedia.org/wiki/Maize" title="Maize" >corn</a> or

<a href="http://en.wikipedia.org/wiki/Sunflower_seed" title="Sunflower seed" >sunflower "seeds"</a>. In the case of <a href="http://en.wikipedia.org/wiki/Sunflower" title="Sunflower" >sunflower</a> and corn "seeds", what is sown is the seed enclosed in a shell or <a href="http://en.wikipedia.org/wiki/Husk" title="Husk" >husk</a>, whereas the potato is a <a href="http://en.wikipedia.org/wiki/Tuber" title="Tuber" >tuber</a>.

Many seeds are <a href="http://en.wikipedia.org/wiki/List_of_edible_seeds" title="List of edible seeds" >edible</a> and the majority of human calories comes from seeds,<a href="http://en.wikipedia.org/wiki/Seed#cite_note-33" >[34]</a> especially from <a href="http://en.wikipedia.org/wiki/Cereal" title="Cereal" >cereals</a>, <a href="http://en.wikipedia.org/wiki/Legume" title="Legume" >legumes</a> and <a href="http://en.wikipedia.org/wiki/Nut_(fruit)" title="Nut (fruit)" >nuts</a>.

Seeds also provide most <a href="http://en.wikipedia.org/wiki/Cooking_oil" title="Cooking oil" >cooking oils</a>, many <a href="http://en.wikipedia.org/wiki/Beverage" title="Beverage" class="mw-redirect" >beverages</a> and <a href="http://en.wikipedia.org/wiki/Spice" title="Spice" >spices</a> and some important <a href="http://en.wikipedia.org/wiki/Food_additive" title="Food additive" >food additives</a>.

In different seeds the <a href="http://en.wikipedia.org/wiki/Embryo#Embryos_of_plants_and_animals" title="Embryo" >seed embryo</a> or the <a href="http://en.wikipedia.org/wiki/Endosperm" title="Endosperm" >endosperm</a> dominates and provides most of the <a href="http://en.wikipedia.org/wiki/Nutrient" title="Nutrient" >nutrients</a>.

The storage <a href="http://en.wikipedia.org/wiki/Protein" title="Protein" >proteins</a> of the embryo and endosperm differ in their <a href="http://en.wikipedia.org/wiki/Amino_acid" title="Amino acid" >amino acid</a> content and physical properties. For example the <a href="http://en.wikipedia.org/wiki/Gluten" title="Gluten" >gluten</a> of wheat, important in providing the <a href="http://en.wikipedia.org/wiki/Elasticity_(physics)" title="Elasticity (physics)" >elastic</a> property to bread <a href="http://en.wikipedia.org/wiki/Dough" title="Dough" >dough</a> is strictly an endosperm protein.

Seeds are used to propagate many crops such as cereals, legumes, <a href="http://en.wikipedia.org/wiki/Forestry" title="Forestry" >forest trees</a>,<a href="http://en.wikipedia.org/wiki/Turfgrass" title="Turfgrass" class="mw-redirect" >turf grasses</a> and <a href="http://en.wikipedia.org/wiki/Pasture" title="Pasture" >pasture</a> grasses.

Particularly in developing countries, a major constraint faced is the inadequacy of the marketing channels to get the seed to poor farmers.<a href="http://en.wikipedia.org/wiki/Seed#cite_note-34" >[35]</a> Thus the use of farmer-retained seed remains quite common.

Seeds are also eaten by <a href="http://en.wikipedia.org/wiki/Animal" title="Animal" >animals</a>, and are fed to <a href="http://en.wikipedia.org/wiki/Livestock" title="Livestock" >livestock</a>. Many seeds are used as <a href="http://en.wikipedia.org/wiki/Birdseed" title="Birdseed" class="mw-redirect" >birdseed</a>.

Seeds

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