cotyledon


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cotyledon

(kŏt'əlēd`ən), in botany, a leaf of the embryo of a seedseed,
fertilized and ripened ovule, consisting of the plant embryo, varying amounts of stored food material, and a protective outer seed coat. Seeds are frequently confused with the fruit enclosing them in flowering plants, especially in grains and nuts.
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. The embryos of flowering plants, or angiospermsangiosperm
, term denoting seed plants in which the ovules, or young seeds, are enclosed within the ovary (that part of the pistil specialized for seed production), in contrast to the gymnosperms, in which the seeds are not enclosed within an ovary.
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, usually have either one cotyledon (the monocots) or two (the dicots). Seeds of gymnosperms, such as pines, may have numerous cotyledons. In some seeds the cotyledons are flat and leaflike; in others, such as the bean, the cotyledons store the seed's food reserve for germination and are fleshy. In most plants the cotyledons emerge above the soil with the seedling as it grows. They differ in form from the true leaves.

Cotyledon

 

one of the first leaves of a plant. The cotyledons form in the seed on the not yet differentiated body of the developing embryo. They often differ sharply in shape, internal structure, and, sometimes, function from subsequent leaves that arise on the growing point of the shoot. Gymnospermous plants have two to 15 cotyledons, dicotyledonous plants two cotyledons, and most monocotyledonous plants one cotyledon. When there is aboveground sprouting of dicotyledon seeds (for example, beans), green cotyledons emerge at the soil surface and for some time perform the functions of green leaves. In peas, oak, walnut, and a number of other plants the cotyledons upon sprouting remain in the seed and die after consumption of nutrient reserves. During the sprouting of many monocotyledons, the sheath portion of the cotyledon emerges from the seed, but the apex remains for some time in the endosperm, functioning as an organ of absorption. The same function is performed by the scutellum that remains in the seed of cereal grains; many botanists consider the scutellum to be a cotyledon.

cotyledon

[‚käd·əl′ēd·ən]
(botany)
The first leaf of the embryo of seed plants.

cotyledon

1. Botany a simple embryonic leaf in seed-bearing plants, which, in some species, forms the first green leaf after germination
2. Anatomy a tuft of villi on the mammalian placenta
References in periodicals archive ?
Cotyledon damage at the seedling stage affects growth and flowering potential in mature plants.
Another feature that appears to be characteristic of charred cowpea is wrinkles present on the inner surface of cotyledons, as illustrated in Figure 2C; however the diagnostic value of this criterion is unknown (Kahlheber 2004).
Light and scanning electron microscope studies on dry beans: intracellular gelatinization of starch in cotyledons of large Lima beans (Phaseolus lunatus).
1A), whereas the highest concentration of fetal CRH RNA was present in STBM obtained by perfusion of a placental cotyledon (Fig.
Cotyledon, the name of a separate genus with rosettes of succulent leaves, has been appended to lewisias.
After six days of culture, the cotyledonary nodes (included both cotyledons, an intact apical bud and 0.
For shoot dry matter (Figure 3A), we observed a mass reduction with an increase with the osmotic potential for all treatments, indicating that free water reduction reduced shoot development, with the allocation of lower cotyledon reserves to the shoot.
Genus Family Order 1 Paulownia Bignoniaceae, Paulowniaceae Lamiales 2 Hymenosporum Pittosporaceae Apiales 3 Cotyledon Crassulaceae Saxifragales 4 Hebe Scrophulariaceae, Plantaginaceae Lamiales 5 Prunus Rosaceae, Amygdalaceae Rosales 6 Hypericum Clusiaceae, Hypericaceae Malpighiales 7 Kunzea Myrtaceae Myrtales 8 Primula Primulaceae Ericales 9 Citrus Rutaceae Sapindales 10 Eremophila Myoporaceae, Scrophulariaceae Lamiales 11 Nicotiana Solanaceae Solanales 12 Gossypium Malvaceae Malvales Genus Floral Formula 1 Paulownia [up arrow] K(5) [?
These traditional therapies decreased bone loss 22 percent to 24 percent, but only soy isoflavones from the cotyledon and germ significantly decreased bone loss by 9 percent and 5 percent, respectively.