The Angiosperm Plant Body Structure and development –Formation of embryo –Mature embryo and seed...

The Angiosperm Plant Body

• Structure and development – Formation of embryo– Mature embryo and seed– Embryo to adult

The structure of the Flower

Fertilization detailed

In most angiosperms, the ovule consists of three layers of tissue:

1.Integuments - two outer layers of diploid (2N) tissue that will develop into the seed coat. 2.Nucellus - the wall of megasporangium, also diploid (2N). 3.Embryo sac - also call the megagametophyte of angiosperms, consists of only 7 cells. Contains 8 haploid nuclei in all.                                                                                    

“Polarity”-Apical- basal pattern- Radial pattern

Embryo development

• Orderly cell division • Differentiation leads into

two distinct parts – Embryo proper– The suspensor

Before this stage is reached the developing embryo is referred to as the proembryo

Becomes food nourishing component

Development of the embryo of a monocot (arrowhead)

Stage of embryo development preceding cotyledon development

• Globular stage- embryo proper is spherical

• Heart stage (dicots only)- seed leaf (cotyledon) development

• Torpedo stage- apical basal pattern just prior to germination

Pre Globular stage- proembryo

Embryo proper will become - meristemic tissue

Future Epidermis

Future Ground meristem (ground)and Procambium (vascular)

Forms the seed coat

Twin embryo development- embryo proper limits the dev of suspensors

(Precursor to vascular)

(nucellar tissue)

(Embryonic root)

Lets look at Seed of some common dicots and monocots

• Garden bean

• Castor bean

• Onion

• Maize

Mature grainor kernel of Wheat

Monocot or dicot?

Grass embryo

Grass embryo

Protective layer of radicle and plumule

-First bud of radicle