Embryo Development
Mature Embryo
Shoot Apical Meristem
Embryo development
Sources:
1.
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Embryonic Axis
Hypocotyl
Radicle
2. http://www.jstor.org/view/00368075/di002288/00p0129i/0
Cotyledons
Goldberg, R.B., G. dePaiva & R., Yadegari. 1994. Plant Embryogenesis:
Zygote to Seed. Science 266:605-614
Root Apical Meristem
Embryogenesis in Angiosperms
Embryogenesis in Capsella
Postfertilization & formation of proembryo
Stages of embryo development
Terminal cell
1. Postfertilization & formation of proembryo
2. Transition from globular proembryo to heart-shaped embryo
3. Organ expansion & maturation
Basal cell
First division
of zygote
Two -celled
proembryo
Four-celled
proembryo
Suspensor
Eight-celled
proembryo
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Embryogenesis in Capsella
Embryogenesis in Capsella
Postfertilization & formation of proembryo
Postfertilization & formation of proembryo
Proembryo
Proembryo
Suspensor
cells
Upper tier
Proembryo
Ground
Meristem
Protoderm
Lower tier
Origin of
Protoderm
Procambium
Basal cell
Hypophysis from
suspensor
Transition from globular proembryo to heart-shaped embryo
Cotyledon initiation
Longitudinal axis
Shoot-Root
axis
Apical-Basal
Organization during
Embryogenesis
Hypocotyl
development
Radicle initiation
Radial axis
Tissue-type axis
Protoderm
Procambium
Ground Meristem
Apical cells (upper tier) Æ cotyledons & Shoot Apical Meristem
Central cells (lower tier) Æ stem, hypocotyl, root and root apical meristem
Hypophysis Æ Columella of root cap & Quiescent Center
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Radial Organization during Embryogenesis
Organ expansion & maturation
Heart Stage
Dermal Tissue System
Torpedo Stage
Fundamental Tissue System
VascularTissue System
Organ expansion & maturation
Walking Stick
Mature Embryo
Mature Embryo
Embryonic Shoot &
Shoot Apical Meristem
Embryonic Axis
Hypocotyl
Radicle
Cotyledons
Root Apical Meristem
3
Embryogenesis in Angiosperms
Stages of embryo development
1. Postfertilization & formation of proembryo
Terminal & basal cell differentiation
Formation of suspensor & globular proembryo
2. Transition from globular proembryo to heart-shaped embryo
Radial axis forms Æ
major tissues Æ dermal, fundamental & vascular
Apical-basal axis forms Æ
Æ shoot & root primordia form
Æ hypocotyl-radicle development
Æ cotyledon initiation
Seed formation
1. Embryo (young sporophyte) development from a zygote
2. Food reserves stored in cotyledons or endosperm
3. Formation of seed coat from Integuments
3. Organ expansion & maturation
Shoot apical meristem forms
Cotyledons enlarge Æ cell ÷ and expansion
Æ Accumulation of storage proteins
Dormancy Æ cessation of RNA & protein synthesis, dehydration &
inhibition of preocious germination
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