Plant Embryo Development

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Plant Embryo

Development

Bolo, Diamos, Go, Marquez, Pilapil


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Embryogenesis

It describes the subsequent period ofdevelopment (after the formation of zygote),during which the zygote undergoes a complexseries of morphological and cellular changes

resulting in the formation of a developmentallyarrested mature embryo.

Embryonic development proceeds within the

confines of the protective maternal tissue of theovule, which becomes the seed coat surroundingthe developing embryo and endosperm


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Asymmetric Cell Division

The initial division of thezygote is transverse andasymmetric, generating asmall, chalazally oriented

apical cell and a large basalcell

Apical cell bulk of the

embryo proper Basal cell part of the

root apex and thesuspensor


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Proembryo

The stages in which there is still no definiteindication of differentiation into embryo properand suspensor

Applies to stages before the initiation of theprotoderm

Sequential longitudinal and transverse divisionsof the apical cell and transverse divisions of thebasal cell before forming the globular embryo.


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Proembryo Stage


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Proembryo

2-celled embryo

Quadrant (4-celled)

Octant (8-celled)

*** Dermatogen Stage (16-celled)


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Globular Stage

The delineation of theprotoderm establishes

the globular stage

embryo, whichincreases in size and

cell number by

anticlinal cell divisions

of the protoderm


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Globular Stage

The cells of the protoderm haveundergone anticlinal divisions.

The interior cells of the embryoproper have undergone additionallongitudinal divisions.

The topmost cell of the suspensorhas divided transversely to producethe hypophysis


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Globular Stage

The cells of the hypophysis havedivided longitudinally.

The cells in the interior of the

embryo proper have divided bothlongitudinally and transversely,while the protodermal cell divisionshave continued.

The developing procambium (pc)becomes visible as elongated cells atthe center of the embryo. gm,ground meristem


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Globular Stage


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Globular Stage


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Heart Stage

Cell divisions parallel to thesurface occur at specificregions of the lateralmargins of the globular

stage embryo, resulting inthe emergence of the twolobes of the cotyledons.

It represents the initialdelineation of the twomajor embryonic organsystems, the cotyledonsand axis.


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Heart Stage


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Heart Stage


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Torpedo Stage

Enlargement of cotyledonsand hypocotyl and furtherelaboration of the radialpattern.

Embryo becomes green andits plastids develop stackedthylakoids

Provascular tissues alsobecome recognizable withincotyledon primordia


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Torpedo Stage

Shoot meristem becomesdiscernible as three

distinct cell layers that will

subsequently attain atunica-corpus

organization (Barton and

Poethig, 1993).

Root-shoot axis forms


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Mature Embryo

The embryo bends due tospace restrictions and thecotyledons eventually reach

the chalazal end of theembryo sac.


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Mature Embryo


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References

Anatomy of Seed Plants by Esau

West, M. & Harada, J. 1993. Embryogenesis inHigher Plants: An Overview. The Plant Cell, Vol.

5, 1361-1369. Berleth and Chatfield. 2002. Embryogenesis:

Pattern Formation from a Single Cell. TheArabidopsis Book

Documents

Plant Embryo Development