Download lec 1 Phytomeres

Growth in Animals
Determinate: Finite Size, Finite Shape, Number and Positions of Organs
May have Larval Stages, Metamorphosis, but each is determinate
Non-local regions of Cell Replication
Growth in Plants
Indeterminate: Final size, number of organs influenced by environment
Type of Organs influenced by environment
Local regions of Cell Replication
Repetitive Growth in Shoot Apex and in Radial/Lateral Meristems
Continuous Growth in Root Apex
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Growth in Plants
Local Increase in Cell Number (Cell Replication)
Local Increase in Cell Size (Elongation)
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Introduction to Plant Growth
Repetitive Production of Phytomeres: a Structural Module
created by a Shoot Apical Meristem (SAM)
Growth of shoots or roots in the Long or Axial Dimension is due to
Shoot Apical Meristems (SAMs) and Root Apical Meristems (RAMs)
These are regions at the apex that contain Stem Cells that replicate
to form Daughter Cells while maintaining the Stem Cells
As they are born and elongate, daughter cells of SAMs displace the
SAMs upward and RAMs downward
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Region where
Shoot
axillary SAM will form
SAM
Root
RAM
Repetitive Growth
From Shoot Apical Meristems
(SAMs)
Nonrepetitive Growth
From Root Apical Meristems
(RAMs)
Growth from Apical Meristems and LDO Primordia
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Apical End/
Apex
/Medial Position
Radial/Lateral
Long Axis = Axial
/
Lateral Position
/Adaxial/
Top
Axillary Position/
Axil
Lateral
Determinate
Organ (LDO)
Basal End/
Base
Internode
Phytomere
Node
Axillary SAM
Axes in Plants
/Abaxial/
Bottom
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SAM Daughter Cells form the Four Parts of the Phytomere
Node: On a stem, the point of insertion of a Lateral Determinate
Organ
Lateral Determinate Organ (LDO): Leaf, Petal, etc. inserted into the
Node. Some consider the LDO to be part of the Node.
Axillary Shoot Apical Meristem (Axillary SAM): in the axil defined by
the distal-most position between the Internode and LDO
Internode: Portion of stem between Nodes
The phytomere derives from the same group of founder cells
In eudicots, the phytomere consists of a node, its axillary SAM, and
the internode above the node
In maize (a monocot), it includes the internode below the node
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Shoot
Florescence
Phytomere
Vegetative
Phytomere
Axillary Vegetative
Shoot Apical
Meristem (V-SAM)
Lateral
Determinate
Organ (LDO)
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5
4
3
Phytomers
2
1
Vegetative Phytomers in Pea
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1o
3o
Active SAM
o
2
4o
o
2
o
3
Inactive Axillary SAM
4o
Branching
Shoots produced by Axillary Shoot Apical Meristems will usually be
identical to the shoot on which they are borne, that is
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SAMs usually produce axillary SAMs of the same Phase
A Case Study in Branching of Vegetative Shoots
Monocot: Poaceae, Grass Family Genus: Phyllostachys, Bamboo
Phyllostachys aurea Carrière ex A. & C. Rivière, Golden Bamboo, Fishpole Bamboo
Introduced; Invasive; Spreads by underground stems = rhizomes; Does not Flower
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A ‘woody’ monocot, although not true wood (not made by vascular cambium)
In this plant, SAMs know what order branch they are on
Outgrowth of Both Axillary SAMs
into Secondary Shoots
Flat surface
Flat surface
Internode
Node
Two Axillary SAMs
Both dormant
Phytomere
Outgrowth of One of Two
Axillary SAMs
into a Tertiary Shoot
Outgrowth of One of Two Axillary
SAMs
into a Secondary Shoot
Phyllostachys aurea Carrière ex A. & C. Rivière, Golden Bamboo, Fishpole Bamboo
Phyllotaxy of Leaves of Primary Shoot = Distichous (2-Ranked; Alternate)
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[Do not have a term for ‘Two Adjacent Axillary SAMs per Node’]
I N
I
N
I
N
I
N
Internode
Node
Two Axillary SAMs
Both dormant
Phytomere
Outgrowth of One of Two Axillary SAMs
into a Secondary Shoot
Phyllostachys aurea Carrière ex A. & C. Rivière, Golden Bamboo, Fishpole Bamboo
Phyllotaxy of Leaves of Primary Shoot = Distichous (2-Ranked; Alternate)
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[Higher Magnification]
A third axillary SAM
at this node in the
Primary Shoot!
Remains dormant
Phyllostachys aurea Carrière ex A. & C. Rivière, Golden Bamboo, Fishpole Bamboo
Phyllotaxy of Leaves of Primary Shoot = Distichous (2-Ranked; Alternate)
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[Do not have a term for ‘Two (or Three!) Adjacent Axillary SAMs per Node’]
Secondary Shoot
Two axillary SAMs per node in Secondary Shoots: One remains dormant.
It is not random; they are on the same side!
Tertiary Shoot
One axillary SAM per node in Tertiary Shoots: remains dormant.
If two axillary SAMs per node, then one grows out.
Phyllostachys aurea Carrière ex A. & C. Rivière, Golden Bamboo, Fishpole Bamboo
Phyllotaxy of Secondary and Tertiary Shoots = Distichous (2-Ranked; Alternate)
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Phase Transitions
Induction of Flowering Converts Apical and Axillary
AdultVeg-SAMs into one of several Reproductive SAMs
JuvV-SAM
AdultV-SAM
Subflor-SAM
Floresc-SAM
Flower-SAM
Large variation in position and complexity of the shoots that bear
flowers: from axillary, solitary flowers to axillary and terminal, highly
branched and complex shoots bearing many flowers
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Phase Transitions
The SAM undergoes Phase Transitions: transitions in the Identity of
the SAM as evidenced by the Identity of the Phytomeres (including the
axillary SAMs) that the SAM produces
Regardless of the Phase of the SAM, it still produces phytomeres
composed of a node, internode, axillary SAM and (usually) a LDO,
although their names may be phase specific
Juvenile Vegetative Shoots - can branch from axillary JuvV-SAMs
Adult Vegetative Shoots - can branch from axillary AdultV-SAMs
Subflorescence Shoots - can branch from axillary Subflor-SAMs
Florescence Shoots - cannot branch; axillary SAMs are Flower SAMs
Flower Shoots - cannot branch; no axillary SAMs
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Vegetative Shoot
Juvenile-Vegetative
Shoot
Lateral
Juv
Determinate Organ
(LDO)
Axillary Shoot
Apical Meristem
(axillary SAM)
1o Shoot Apical
Meristem (SAM)
Leaf
JuvV-SAM
JuvV-SAM
Inflorescence
Adult-Vegetative Subflorescence Florescence
Shoot
(Branched Shoot) (Floral Shoot)
Flower
Shoot
Adult Leaf
S P St C
AdultV-SAM
AdultV-SAM
Cauline Leaf
Subflor-SAM
Subflor-SAM
Bract
Flower-SAM
Floresc-SAM
Flower-SAM
1o
Full Series of Phase Tansitions
with development of all LDOs
and some axillary SAMs
3o
3o
2o
3o
2o
Terminal Inflorescences Only
2o
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Vegetative Shoot
Juvenile-Vegetative
Shoot
Lateral
Juv
Determinate Organ
(LDO)
Axillary Shoot
Apical Meristem
(axillary SAM)
1o Shoot Apical
Meristem (SAM)
Leaf
JuvV-SAM
JuvV-SAM
Inflorescence
Adult-Vegetative
Shoot
Florescence
(Floral Shoot)
Flower
Shoot
Adult Leaf
Bract
S P St C
AdultV-SAM
AdultV-SAM
S P St C
Flower-SAM
Floresc-SAM
Flower-SAM
1o
Terminal Florescences;
no Subflorescence Phase
3o
Plus Terminal Flower
3o
2o
2o
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Vegetative Shoot
Juvenile-Vegetative
Shoot
Lateral
Juv
Determinate Organ
(LDO)
Axillary Shoot
Apical Meristem
(axillary SAM)
1o Shoot Apical
Meristem (SAM)
Leaf
JuvV-SAM
JuvV-SAM
Inflorescence
Adult-Vegetative
Shoot
Florescence
(Floral Shoot)
Flower
Shoot
Adult Leaf
Bract
S P St C
Floresc-SAM
AdultV-SAM
S P St C
Flower-SAM
Floresc-SAM
Flower-SAM
1o
Terminal and Axillary Florescences;
no Subflorescence Phase
3o
Plus Terminal Flower
3o
2o
2o
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Vegetative Shoot
Juvenile-Vegetative
Shoot
Lateral
Juv
Determinate Organ
(LDO)
Axillary Shoot
Apical Meristem
(axillary SAM)
1o Shoot Apical
Meristem (SAM)
Leaf
JuvV-SAM
JuvV-SAM
Inflorescence
Adult-Vegetative
Shoot
Flower
Shoot
S P St C
Adult Leaf
S P St C
Flower-SAM
AdultV-SAM
1o
Solitary, Axillary Flowers
Plus Gradual Change in AdultV LDO
3o
3o
2o
2o
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Florescence
Phytomer
Tertiary
Inflorescence
Flower containing 4 phytomers
Primary Florescence/ Floral Shoot
(No Branching)
Axillary SAMs are Flower-SAMs
Subflorescence
(Branched, Branchable)
Subflorescence
Phytomere
Lateral Rosette
Inflorescence
Primary Inflorescence/
Reproductive Shoot
Axillary SAMs are Subflor-SAMs
Vegetative
Shoot
Arabidopsis
Fig. 9.8A L&D
Vegetative and Reproductive Structures and Phytomeres
The Florescence is the apical, unbranched, part of an Inflorescence
Warning: There are other nomenclatures for reproductive structures
In Taxonomy, ‘Inflorescence’ usually includes Inflorescence, Florescence, and Flowers;
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for example, ‘Inflorescences axillary, solitary flowers’
3
primary
Types of Phytomeres:
1 = Basal [Vegetative] Rosette (same use as GG)
2 = Basal part of Flowering [Inflorescence] Stalk
[the Subflorescence as used by GG]
3 = Florescence (same use as GG)
Types of Branches containing ….
Type 3 on Primary Shoot = Primary Florescence
(Florescence on 1o shoot as used by GG)
Type 3 Collectively = Coflorescence (no GG term)
Type 2 and Type 1 = Paraclade (Higher-order
Inflorescences as used by GG)
Types 1+2+3 Collectively = Inflorescence
3
primary
3
2
2
rosette
secondary
paraclade
1
An Alternative Nomenclature for Arabidopsis 22
Vegetative Shoot
Inflorescence
Juvenile-Vegetative Adult-Vegetative
Shoot
Shoot
Lateral
Juv
Determinate Organ
(LDO)
Axillary Shoot
Apical Meristem
(SAM)
1o Shoot Apical
Meristem (SAM)
Leaf
Subflor-SAM
Adult Leaf
Cauline Leaf
None
None
Subflor-SAM
Accessory
Subflor-SAM
JuvV-SAM
Subflorescence
Florescence
(Branched Shoot) (Floral Shoot)
Flower
Shoot
S P St C
Flower-SAM
Accessory
Subflor-SAM
AdultV-SAM
Subflor-SAM
Floresc-SAM
1o
2o
3o
3o
1o
2o
2o
Arabidopsis violates
several rules
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Vegetative Shoot
Juvenile-Vegetative
Shoot
Lateral
Juv
Determinate Organ
(LDO)
Axillary Shoot
Apical Meristem
(axillary SAM)
1o Shoot Apical
Meristem (SAM)
Leaf
Inflorescence
Adult-Vegetative
Shoot
Adult Leaf
JuvV-SAM
JuvV-SAM
Flower
Shoot
S P St C
Bract
S P St C
Floresc-SAM
AdultV-SAM
1o
3o
Axillary, not terminal, Florescences;
no Subflorescence Phase
3o
2o
2o
Plus Gradual Change in AdultV LDO
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