From Seed to Tree II
Slide One – from primary to secondary plant body
•Shoot and root primary growth
Slide Two – internal architecture of herbs (primary growth)
Slide Three – primary growth
•Needed:
oPrimary meristems
Shoot apical meristem
Root apical meristem
oSecondary meristems
Vascular cambium
Ground meristem
•Which occurs very close to root and shoot apical meristems
Also less important (but not focused on)
•Axillary meristem
•Lateral root meristem
Slide Four / Six – primary growth in shoots
•Shoot apical meristem
oProtected by leaf primordium
eg leaves of cabbage protecting the shoot stub
•produces new cells through mitotic cell division
•undergoes elongation
•differentiation and maturation occurs in the zone under the region of
elongation
odifferentiate between
leaf primordium
shoot apical meristem
procambium (or protocambium)
•eg car prototype
•will turn into the vascular cambium in the zone of
maturation producing primary phloem towards the outside
and primary xylem towards the interior
protoderm
•predecessor of the epidermis
ground meristem
•becomes the cortex containing some omnipotent cells
which give rise to differentiated cells further down
•initiates the production of collenchyma which are
strengthening cell types around the vascular bundles
epidermis
cortex (parenchyma and some collenchymas)
vascular cambium
•thin layer divides the phloem to the outside and xylem to
the inside
primary phloem
primary xylem
collenchyma
•cap strengthening the vascular bundle towards the outside
pith
Slide Seven – shoot primary tissue diagram
Slide Eight / Twelve – primary growth in roots
•bottom up:
oroot cap