Scutellum in corn not coconuts
dstarret at BIOLOGY.SEMO.EDU
Fri Aug 13 19:33:07 EST 1999
> My understanding about the difference between monocots and dicots
>is that dicots absorb the endosperm during embryo formation/maturation to
>form large cotyledons and monocots absorb the endosperm via their single
>cotyledon during seed germination. The scutellum is the term for the
>specialized absorbtive cotyledon found in grasses and is not used for other
> Simpson and Ogorzaly (Economic Botany-Plants in our World, 2nd
>Edition, pages 136-138) state "The [coconut] fruit is formed from a flower
>with 3 carpels (each represented by an 'eye' of the coconut), only one of
>which develops. The mature fruit contains one seed, the largest known. The
>embryo itself is small and located near the stem end. Initially the
>endosperm is a liquid containing free nuclei. This liquid, called coconut
>water or coconut milk, is drunk from green coconuts in many tropical
>countries. As the endosperm matures, cell walls form around the nuclei,
>and the endosperm solidifies into an oil-rich layer of coconut "meat"
>inside the seed coat. It is the solidified endosperm that we eat...
> If mature coconuts are not used or harmed, the embryo can germinate
>within the coconut since there is no dormancy period. The germinating
>seedling eventually extends the tip of the cotyledon through one of the
>eyes. The base of the embryo swells into an absorbing organ that
>eventually fills the entire cavity of the coconut as it digests the
>endosperm. The swollen organ, called a coconut apple, can also be eaten. "
> I am not sure that Simpson and Ogorzaly have correctly identified
>the coconut apple as being part of the embryo proper. It may actually be
>the cotyledon which swells during germination and begins to absorb the
> Bowes (A color atlas of plant structure, page 148) states "In palms
>the cotyledon often enlarges greatly and becomes haustorial..."
> In either case the cotyledon of coconuts is very small until after
>seed germination. I hope that this is useful.
Tyhanks for these instights. So, how does the meat get so evenly distributed?
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