The Angiosperm Plant Body
• Structure and development
– Formation of embryo
– Mature embryo and seed
– Embryo to adult
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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
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Monocot or Dicot?
• Solanum caroliense
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Monocot or Dicot?
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Monocot or Dicot?
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Monocot or Dicot?
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Monocot or Dicot?
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Monocot or Dicot?
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Development of the embryo of a
monocot (arrowhead)
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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
Pre Globular stage- proembryo
Future Epidermis
Future Ground meristem (ground)
and Procambium (vascular)
Embryo proper
will become
- meristemic tissue
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
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Grass embryo
Mature grain
or kernel of
Wheat
Monocot or dicot?
Grass embryo
-First bud of radicle
Protective layer of
radicle
and plumule