Plant cell expansion, division, morphogenesis & differentiation
Growth, morphogenesis and cell differentiation produce the plant body:
Cells form specialised tissues and organs through the process of
development.
Developmental plasticity describes the effect of environment on
development:
For example, the aquatic plant Cabomba caroliana forms different leaves
depending on whether or not the apical meristem is submerged.
Underwater leaves are feathery, which reduces their resistance to moving
water. Surface leaves are pads that aid in flotation. Cells in these leaves
are genetically identical – the environment of the apical meristem
influences expression of leaf shape genes.
Development consists of growth, morphogenesis and cell differentiation:
Growth is an irreversible increase in size
Morphogenesis is the development of body form and organisation
Cell differentiation is the process by which cells with the same genes
become different from each other
Growth: cell division and cell expansion:
Cell division in meristems increases cell number and the potential for
growth.
However, cell expansion accounts for the actual increase in plant size.
The Plane and Symmetry of Cell Division:
New cell walls form in a plane (direction) perpendicular to the main axis of
cell expansion.
The plane in which a cell divides is determined during late interphase.
Microtubules become concentrated into a ring called the preprophase
band that predicts the future plane of cell division.
Leaf growth results from a combination of transverse and longitudinal cell
divisions.
It has long been thought that the plane of cell division determines leaf
form.
However, a mutation in the tangled-1 gene in maize (sweet corn) that
affects longitudinal divisions does not affect leaf shape: mutant leaves
grow more slowly than wild-type but their overall shape is unaffected.
Therefore, leaf shape does not depend solely on precise spatial control of
cell division.
Although the plane of cell division does not solely determine the shape of
plant organs, the symmetry of cell division, the distribution of cytoplasm
between daughter cells, determines cell fate.
Asymmetrical cell division signals a key event in development: for
example, the formation of guard cells involves asymmetrical cell division
Growth, morphogenesis and cell differentiation produce the plant body:
Cells form specialised tissues and organs through the process of
development.
Developmental plasticity describes the effect of environment on
development:
For example, the aquatic plant Cabomba caroliana forms different leaves
depending on whether or not the apical meristem is submerged.
Underwater leaves are feathery, which reduces their resistance to moving
water. Surface leaves are pads that aid in flotation. Cells in these leaves
are genetically identical – the environment of the apical meristem
influences expression of leaf shape genes.
Development consists of growth, morphogenesis and cell differentiation:
Growth is an irreversible increase in size
Morphogenesis is the development of body form and organisation
Cell differentiation is the process by which cells with the same genes
become different from each other
Growth: cell division and cell expansion:
Cell division in meristems increases cell number and the potential for
growth.
However, cell expansion accounts for the actual increase in plant size.
The Plane and Symmetry of Cell Division:
New cell walls form in a plane (direction) perpendicular to the main axis of
cell expansion.
The plane in which a cell divides is determined during late interphase.
Microtubules become concentrated into a ring called the preprophase
band that predicts the future plane of cell division.
Leaf growth results from a combination of transverse and longitudinal cell
divisions.
It has long been thought that the plane of cell division determines leaf
form.
However, a mutation in the tangled-1 gene in maize (sweet corn) that
affects longitudinal divisions does not affect leaf shape: mutant leaves
grow more slowly than wild-type but their overall shape is unaffected.
Therefore, leaf shape does not depend solely on precise spatial control of
cell division.
Although the plane of cell division does not solely determine the shape of
plant organs, the symmetry of cell division, the distribution of cytoplasm
between daughter cells, determines cell fate.
Asymmetrical cell division signals a key event in development: for
example, the formation of guard cells involves asymmetrical cell division
