Angiosperm Plant Body - Botany - Lecture Slides, Slides of Botany and Agronomy

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The Angiosperm Plant Body

• Structure and development

– Formation of embryo

– Mature embryo and seed

– Embryo to adult

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

Stage of embryo development

preceding cotyledon development

• Globular stage- embryo proper

(proembryo) is spherical

• Heart stage (dicots only)- seed leaf

(cotyledon) development

• Torpedo stage- apical basal pattern just

prior to germination

Stages of embryo development

Stages of embryo development

Globar stage

Heart stage (dicot only)

Torpedo stage

Embryo proper

will become

- meristemic tissue

Future Epidermis

Future Ground meristem (ground)

and Procambium (vascular)

Forms the seed coat

(nucellar tissue)

(Embryonic root)