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

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Taproot

Lateral roots

Sh

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Taproot

Lateral roots

Leaves

Stem

Sh

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Taproot

Lateral roots

BranchLeaves

Stem

Sh

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Taproot

Lateral roots

Apical bud

BranchLeaves

Stem

Sh

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mLateral bud

Taproot

Lateral roots

Apical bud

Branch

Node

Internode

Leaves

Lateral bud

Stem

NodeS

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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

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Root

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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

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Matu

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Zon

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Elo

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Zon

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Div

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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

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ivis

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Diff

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Div

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Diff

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Div

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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