Transcript Introduction to leaf development

Plant Organization:
Leaf development
Organization
Organization in plants is dependent upon
programmed, controlled cell division,
followed by growth, further cell division
and ultimately, differentiation.
Programmed and controlled cell division
occurs within the domain of the
vegetative apex.
Leaves also follow a programmed
development process
the apex
All the tissues within the apex differentiate
rapidly. By about 150 µm, cells within the
apical region are starting to differentiate. In
the pine apex (above), you can see developing
leaflets.
The Coleus apex to the right, shows
rapidly developing leaflets beneath the
apical dome.
internal organization
adaxial epidermis
palisade mesophyll
vascular bundles
spongy mesophyll
stomata
leaf development
these form the epidermis
and associated structures
marginal
two types of initials
submarginal
these form mesophyll as
well as the procambial
and cambial tissue
how organized?
epidermal, mesophyll and vascular
tissues are organized and
develop in specific ways.
What is the control mechanism?
structural & functional tissue
dermal
non- vascular
vascular
dermal
two meristems
marginal
sub marginal
deriving procambium
marginal
sub marginal
procambium
Esau’s developmental outline
upper epidermis
palisade
parenchyma
bundle sheath
Vascular bundles
procambium
MI
SI
bundle sheath
middle spongy parenchyma
lower spongy parenchyma
lower epidermis
see
notes below
no middle spongy layer?
upper epidermis
palisade
parenchyma
bundle sheath
MI
SI
procambium
vascular bundles
bundle sheath
lower spongy parenchyma
lower epidermis
add a mestome sheath
upper epidermis
palisade
parenchyma
bundle sheath
mestome sheath
MI
SI
procambium
vascular bundles
mestome sheath
bundle sheath
lower spongy parenchyma
Notes
lower epidermis