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Seed- This writeup is about biological seeds; for the Buddhist metaphor, see bija.
A seed is the ripened ovule of gymnosperm or angiosperm plants. The importance of the seed relative to more primitive forms of reproduction and dispersal is attested to by the success of these two groups of plants in dominating the landscape.
Seed structure
A seed contains the embryo from which a new plant will grow under proper conditions. It also contains a supply of stored food and is wrapped in a seed coat. The stored food begins as a tissue called endosperm derived from the parent plant. Endosperm becomes rich in oil or starch, and protein. In some species, the embryo is imbedded in the endosperm, 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. Some common plant seeds that lack an endosperm are bean, pea, oak, walnut, squash, sunflower, and radish. Plant seeds with an endosperm include all coniferss and most monocotyledons (e.g. grasses and palms), and also e.g. brazil nut, castor bean.
The seed coat develops from tissues (called integument) originally surrounding the ovule. The seed coat in the mature seed can be a paper thin layer (for example, peanut) or something more substantial.
The seeds of angiosperms are contained in a hard or fleshy (or with layers of both) structure called a fruit. Gymnosperm seeds begin their development "naked" on the bracts of cones, although the seeds do become covered by the cone scales as they develop. An example of a hard fruit layer surrounding the actual seed is that of the so-called stone fruits (such as the peach).
Seed functions
Unlike animals, plants are limited in their ability to seek out favorable conditions for life and growth. Consequently, plants have evolved many ways to disperse and spread the population through 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. Those properties or attributes that promote the movement of the next generation away from the parent plant may involve the fruit more so than the seeds themselves. The function of a seed typically is one of serving as a delaying mechanism: a way for the new generation to suspend its growth and allow time for dispersal to occur or to survive harsh, unfavorable conditions of cold or dryness or both. In many if not most cases each plant species achieves success in finding ideal locations for placement of its seeds through the basic approach of producing numerous seeds. This is certainly the approach used by plants, such as ferns, that disperse by spores. However, seeds involve a considerably greater investment in energy and resources than do spores, and the payoff must come in achieving similar or greater success with fewer dispersal units.
See also
External links
A Seed in Final Fantasy VIII is a mercenary working for a Garden.
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Beak Appetit
Natural cooked diets for all tropical birds, available in six flavors.
http://www.beakappetit.com/
And Feathers Bird Studio
Mixes based on seeds, nuts, grains and dried fruit, and treats as well as vitamins and minerals.
http://www.andfeathers.com/
Brightwood Birds
Provides seed mixture, vitamins and supplements. Also offers advisory services and seminars.
http://brightwoodbirds.home.att.net/
Harrison's Bird Foods
Provides organic food for different species.
http://harrisonsbirdfoods.com/
DD Pet Products, Inc.
Manufacturer of foods and treats. List of products with photographs and tips on how to get your bird to eat healthier.
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The Birdcare Company
Includes eggfood, supplements, hand rearing foods, and complete diets as well as medicines and cleaners. Also featuring birdcare articles.
http://www.birdcareco.com/
Lexi Bread
Offering all natural biscuits, several flavors available.
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Garden Fresh
Offers several kind of seed and treat mixes for all type of birds from large hookbills to small finches.
http://www.gardenfreshbirdseed.com/
Love Nest Products
Retailing a dry mix with seeds and grain.
http://www.lovenestproducts.com/
Gonzo's Gourmet Birdcakes
Hookbill blends of fruits and vegetables available in 15 and 30-day supplies, also parrot puzzle toys.
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Nibble Nest
Food for lovebirds, finches, and cockatiels. Also toys, treats and bedding material.
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Rainbow Landing
Lorikeet nectar formulated for exhibition and breeding.
http://www.rainbowlanding.com
Amazon Paradise
Food for pet birds, fly and moth traps, and jewelry.
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Our Farm
Offers home grown spray millet and alfalfa cubes.
http://www.uteach2.com/ourfarm/our_farm.htm
Itty Bitty Birdie Bites
Food and treats made from human-grade ingredients with no additives.
http://www.ittybittybirdiebites.com
Carr's Natural Feeds
Offers natural feeds for pigeons, chickens, wild birds, poultry, and fishing.
http://www.naturalfeeds.co.uk/
Country Lane Bird Feeds
Offers a selection of wild bird feed, including suet. Monthly newsletter available.
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Maine Wild Bird Food Company
Custom feed mixes. Wholesale information available.
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NE Wild Bird Food Company
Variety of feed including blends, sunflower, safflower, nyger seed, and peanuts. Includes wholesale information.
http://www.newildbirdfood.com/
Bird Seed Central
Seed products for wild birds and other backyard wildlife. Offers a club plan.
http://www.birdseedcentral.com/
Prairie Premium Products
Sells a variety of wild bird feeds, including black oil sunflower and safflower seeds, cracked corn, and nyjer thistle.
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PRD Bird Seed
Wild bird mixes, including millet, niger, safflower, and sunflower seeds. Wholesale information available.
http://www.prdseed.com/
eBirdseed
Selection of seed products. Offers a subscription service with automatic delivery of seed at regular intervals.
http://www.eBirdseed.com/
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