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 ?
Presence of BAP+Kn in MS medium along with CM induced multiple shoot buds in callus derived from cotyledonary leaf explants.
Natural regeneration of Ginkgo biloba from downward growing cotyledonary buds (basal chichi).
Formation of aescin glucosides by callus tissue from cotyledonary explants of Aesculus hippocastanum L.
a) Cotyledonary explants cultured on M2 (zeatin + IAA + Put) medium (b) Epicotyl explants cultured on M2 (zeatin + IAA+ Put) medium (c) Cotyledonary explants cultured on M4 (zeatinriboside + IAA+ Put) medium (d) Epicotyl explants cultured on M4 (zeatinriboside + IAA+ Put) medium (e) Cotyledonary explants cultured on M6 (zeatinriboside + NAA + BAP + Put) medium (f) Epicotyl explants cultured on M6 (zeatinriboside + NAA + BAP + Put) medium explants of Pusa Ruby 24.
2003) who reported that cotyledonary nodes yielded the best multiple shoot regeneration in chickpea.
In current study, an efficient and stable Agrobacterium-mediated genetic transformation approach using cotyledonary node explants in cucumber with CsEXP10 gene has been developed, which can be successfully used for the introduction and functional analysis of desired genes.
The cotyledonary petiole (Figure 3B) has uniseriate epidermis with unicellular non-glandular trichomes, collenchymatous and parenchymatous cortex and three collateral vascular bundles.
According to previous studies of cotton tissue culture, callus culture can be initiated from different explants such as hypocotyls, radicals, tissues of embryo, shoot apex, cotyledonary leaves etc.
Plants remained under stress until the cotyledonary leaves wilted and hung down, with abscission of 50%.
Collections started in March 2012, when megastrobili were immature and embryos were at the cotyledonary stage-control treatment (29th March) (Guerra et al.