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

Shoo

t sy

stem

Root

sys

tem

Taproot

Lateral roots

Shoo

t sy

stem

Root

sys

tem

Taproot

Lateral roots

Leaves

Stem

Shoo

t sy

stem

Root

sys

tem

Taproot

Lateral roots

BranchLeaves

Stem

Shoo

t sy

stem

Root

sys

tem

Taproot

Lateral roots

Apical bud

BranchLeaves

Stem

Shoo

t sy

stem

Root

sys

tem

Lateral bud

Taproot

Lateral roots

Apical bud

Branch

NodeInternode

Leaves

Lateral bud

Stem

NodeSh

oot

syst

emRo

ot s

yste

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 lightFix CO2

Storage• Food• Water

SupportProtection (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)

Shoo

t sys

tem

Root

sys

tem

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

Zone

of

Cellu

lar

Mat

urat

ion

Zone

of

Cellu

lar

Elon

gati

on

Zone

of

Cellu

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

Epidermis

Cortex

Pith (ground tissue)

Vascular bundle

Secondary Growth

Detailed view of vascular bundle in a eudicot

Epidermis

Collenchyma

Phloem

Xylem

Cambium

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 phloemBark

Wood

Parenchyma cells (in rays)

Vascular cambium

Cork cambiumCork

Secondary xylem

Gro

wth Di

visio

nDi

ffere

ntia

tion

Divi

sion

Diffe

rent

iatio

nDi

visio

n Diffe

rent

iatio

n

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