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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