Seed Structure and Development
Following the fertilizations in the embryo sac, the zygote divides repeatedly by mitosis and
differentiates into an
embryo
. The endosperm nucleus also divides by mitosis and forms the
endosperm
tissue, which provides food for the developing embryo.
The early embryo is linear with apical meristems on either end and one or two seed leaves or
cotyledons
. The axis below the cotyledons is called the
hypocotyl
, at the tip of which is the
radicle
that gives rise to the primary root of the seedling. The axis above the attachment of the cotyledons is
the
epicotyl
, which also ends in an apical meristem. In some seeds, the first foliage leaves are
formed in the seed. The area above the cotyledons is thus a miniature shoot and is called the
plumule
. In some taxa, food for the embryo remains within endosperm tissue and the cotyledons
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- Fall '08
- Farr
- Mitosis, Sperm, Zygote, Seed Coat, cotyledons, endosperm tissue
-
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