cotyledon


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cotyledon

 [kot″ĭ-le´don]
1. any subdivision of the uterine surface of the placenta.
2. irregular convex areas on the chorionic surface of the placenta, consisting of two or more stem villi and their many branch villi; by the end of the fourth month the decidua basalis is almost entirely replaced by the cotyledons.

cot·y·le·don

(kot'i-lē'don),
1.
2. In plants, a seed leaf, the first leaf to grow from a seed.
3. A placental unit.
[G. kotylēdon, any cup-shaped hollow]

cotyledon

(kŏt′l-ēd′n)
n.
1. Botany A leaf of the embryo of a seed plant, which upon germination either remains in the seed or emerges, enlarges, and becomes green. Also called seed leaf.
2. Anatomy One of the lobules constituting the uterine side of the mammalian placenta, consisting mainly of a rounded mass of villi.

cot′y·le′don·ar′y (-ēd′n-ĕr′ē), cot′y·le′don·al (-ēd′n-əl)(-ēd′n-əs), cot′y·le′do·nous (-ēd′n-əs) adj.

cot·y·le·don

(kot'i-lē'dŏn)
1. In plants, a seed leaf, the first leaf to grow from a seed.
2. Irregular convex area of the fetal part of the placenta composed of stem villi.
[G. kotylēdon, any cup-shaped hollow]

cotyledon

  1. a part of the plant embryo in the form of a specialized seed leaf that can be thin and papery, as in the castor oil plant, or can act as a storage organ, as in the broad bean, absorbing food from the endosperm. Sometimes it also functions as a leaf after EPIGEAL germination, as in the runner bean. Some ANGIOSPERMS have one cotyledon per seed (MONOCOTYLEDONS) while others have two (DICOTYLEDONS).
  2. a part of the mammalian placenta on which a tuft of villi occurs, particularly in ruminants.
References in periodicals archive ?
Somatic embryogenesis protocol: cotyledons were cultured in culture jars with 20 ml of the somatic induction medium (SIM; Collado et al., 2010) in darkness at 25.0[degrees]C [+ or -] 2.0.
The first germination count was carried out concomitantly with the emergence test, and was the number of germinated seeds at 21 DAS, considering as germinated the diaspores that showed protrusion of the cotyledon petiole.
However, cotyledon explants showed highest potential of callus formation (54%) on MS medium supplemented with 4.0 mg/L NAA and was exploited for subsequent extensive experiments with different other PGRs (Table 1).
Count averages on the cotyledons were low and there were no significant differences between treatments in the number of immatures (F = 0.98, df = 1, 57, P = 0.3233) or adults (F = 0.0, df = 1, 57, P = 0.9600) observed on d 7, or the eggs (F = 0.04, df = 1, 57, P = 0.8454), immatures (F = 1.55, df = 1, 57, P = 0.2182), or adults (F = 0.66, df = 1, 57, P = 0.4207) observed on d 14.
[4] Maternal surface is divided into cotyledons with irregular grooves in between.
Protocols that use cotyledon explants have higher rooting rates compared to micropropagation based on nodal segments of adult plants.
The cotyledons showed no significant differences between any of the treatments and the fungicide or the untreated (data not shown).
Studied factors included two Iranian cumin landraces, Golestan and North Khorasan, two explants, hypocotyl and cotyledon, and 7 different concentrations of PGRs (Table 2).
Table 2 revealed that the single zoosporangium isolate DU1943M4 showed a significant difference, producing more than 18 x [10.sup.5] zoosporangia per cotyledon as compared to a mean of 12 x [10.sup.5] zoosporangia per cotyledon for the other four isolates.