A single archesporial cell differentiated under a single layer of epidermal cells in the young nucellus
Other models have been proposed that depend on the degree of active secretion that is occurring from the nucellus
(Tomlinson et al.
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As it was observed in the presented study, the nucellus
of the Fabaceae ovules is crassinucellate (Prakash, 1987), and which has been considered to be the primitive condition in angiosperms (Sporne, 1969).
Carpel with receptive stigma: in the few conifers with extended siphonogamy the site of pollen reception is imprecise and the target for the pollen tube is still the nucellus
or its extension, whereas in Angiosperms the stigmatic surface of the carpel is a more precise site for pollen reception.
At the post-pollination stage, also, shade and water deficit substantially decreased carbohydrate accumulation by the endosperm and nucellus
The ovules of Rapateaceae are also remarkably similar to those of Dasypogon and Calectasia, exhibiting a massive starchy nucellus
(Venturelli & Bouman 1988; see also Rudall 1994; Rudall & Chase 1996).
The term perisperm is a term used for the remains of the nucellus
in dicotyledonous seeds (Fahn 1982) and could be used for the remains of the nucellus
covering the micropylar end of the female gametophyte, but not for the pleurotesta.
In 75 % of the aberrant ovules, a portion of the nucellus
was exposed and no micropyle was present.
soft layer fused with the nucellus
which forms the pachychalaza.
Crane and Carman (1987) hypothesized that regulatory substances from the nucellus
diffuse through the callose-deficient MMC, interfer with meiosis, and induce a mitotic-like division.
As the embryo develops, it becomes torpedo shaped, grows two cotyledons, and absorbs the endosperm and eventually the nucellus
to occupy nearly all of the space within the ovary wall.