Plant structure- cells, tissue, organisation & growth
Leaves and photosynthesis
C4 photosynthesis
CAM photosynthesis
Plant water relations
Plants and nutrients
Plant reproduction- asexual- sexual reproduction
- pollination- seed dispersal
Sh
oot
syste
mR
oot
syste
m
Taproot
Lateral roots
Sh
oot
syste
mR
oot
syste
m
Taproot
Lateral roots
Leaves
Stem
Sh
oot
syste
mR
oot
syste
m
Taproot
Lateral roots
BranchLeaves
Stem
Sh
oot
syste
mR
oot
syste
m
Taproot
Lateral roots
Apical bud
BranchLeaves
Stem
Sh
oot
syste
mR
oot
syste
mLateral bud
Taproot
Lateral roots
Apical bud
Branch
Node
Internode
Leaves
Lateral bud
Stem
NodeS
hoot
syste
mR
oot
syste
m
Basic functions of roots, stems and leaves:
Roots
Roots:• Find and absorb water• Find and absorb nutrients• Host symbionts• Anchorage and support• Attachment• Photosynthesis• Storage• Breathing or ventilation (mangroves)• Reproduction
Absorbing water and nutrients
Host symbionts
Roots of pea plant
Nodules
Anchorage and support
Attachment
Photosynthesis!
Storage
pneumatophores
Asexual reproduction
Stems
Transport and support.
Cactus stems store water, photosynthesize.
Stolons produce new individuals at nodes above ground.
Rhizomes produce new individuals at nodes below ground.
Tubers store carbohydrates.
Thorns provide protection.
Leaves Intercept light
Fix CO2
Storage• Food• Water
Support
Protection (spines)
Collect nutrients• Animals• Leaves and compost
Reproduction• Asexual• Sexual (pollination)
Transport of water, sugar, and nutrients through vascular tissue
CO2
Sunlight
Water
Nutrients(such as N, P, K)
Shoot
syst
em
Root
syste
m
Plant structure- cells, tissue, organisation & growth
Leaves and photosynthesis
C4 photosynthesis
CAM photosynthesis
Plant water relations
Plants and nutrients
Plant reproduction• asexual• sexual reproduction
- pollination- seed dispersal
Growth
Determinate growth
Growth
Determinate growth
Indeterminate growth
Growth
Determinate growth
Indeterminate growth
Growth
Determinate growth
Indeterminate growth
Vascular tissue
(b) Close-up of root tip
Ground tissue
Epidermal tissue
Apical mersitem
Sloughed-off root cap cells
Root cap
Root hair
Zon
e o
fC
ellu
lar
Matu
rati
on
Zon
e o
fC
ellu
lar
Elo
ng
ati
on
Zon
e o
fC
ellu
lar
Div
isio
nLateral root
(a) Longitudinal section of root segment
mucilage
Primary Growth
Leaf primordia
Apical meristem at tip of shoot
Apical meristem in lateral bud
Primary Growth
Primary growth
Cross section of a eudicot stem Cross section of a eudicot stem
EpidermisEpidermis
CortexCortex
Pith (ground tissue)Pith (ground tissue)
Vascular bundleVascular bundle
Secondary Growth
Detailed view of vascular bundle in a eudicot
EpidermisEpidermis
Collenchyma
PhloemPhloem
XylemXylem
CambiumCambium
Secondary meristem = cambium
Secondary meristem = cambium
Cylinders the length of root or stem
Secondary meristem = cambium
Cylinders the length of root or stem
Increase width of stems and roots
Vascular cambium adds cells on inside and outside
Woody stems contain two lateral meristems.
Cork cambium adds cells to the outside
Vascular cambium adds cells on inside and outside
Woody stems contain two lateral meristems.
Wood and bark contain a variety of cells and tissues.
Secondary phloemSecondary phloem
BarkBark
WoodWood
Parenchyma cells (in rays)Parenchyma cells (in rays)
Vascular cambiumVascular cambium
Cork cambiumCork cambium
CorkCork
Secondary xylem
Gro
wth D
ivis
ion
Diff
ere
nti
ati
on
Div
isio
n
Diff
ere
nti
ati
on
Div
isio
n Diff
ere
nti
ati
on
Time
Secondary phloem
Vascular cambium
Secondary xylem
Heartwood and sapwood have different functions.
Heartwoodprovides structural support but no longer transports water
Sapwoodtransports water
Bark
Growth rings result from variation in cell size.
One growth ring
Early wood
Late wood
Increment borer cuts core from trunk.
Core samples from three nearby trees
These samples are lined up by year; notice similar ring patterns in trees from the same area