PLANTS Evolution of Plants The Plant Body Plant

PLANTS

Evolution of Plants

The Plant Body

Plant Tissue Systems • Dermal – Cuticle • Vascular – Xylem • Tracheids • Vessel elements – Phloem • Sieve-tube members • Companion cells

Xylem

Phloem

Plant Tissue Systems • Ground – Parenchyma – Collenchyma – Sclerenchyma

Plant Growth • Apical meristems – Primary growth • Lateral meristems – Secondary growth

Root Structure • Epidermis – Root hairs • Cortex • Endodermis – Casparian strip • Vascular cylinder – Pericycle – Xylem, phloem, pith

Primary Root Growth

Primary Stem Structure • Epidermis – Cutin • Cortex • Vascular cylinder – Xylem, phloem, pith – Vascular cambium

Secondary Stem Structure • Vascular cambium – Secondary xylem – Secondary phloem • Cork cambium – Periderm

Leaf Structure • Epidermis – Cuticle – Cutin • Palisade • Spongy • Guard cells – Stomata • Vascular bundles

Transport in Plants

Transport in Plants • Osmosis – Root pressure • Capillary action – Adhesion – Cohesion • Water potential

Lateral Transport

Xylem Sap Transport • Root pressure – Guttation • Transpirational pull • Adhesion / Cohesion

Control of Transpiration

Pressure Flow Model

Photoperiodism • Circadian rhythm • Flowering plants – Phytochrome, Florigen

Plant Tropisms • • Gravitropism Phototropism Thigmotropism Peter Boysen-Jensen – Coleoptile • F. W. Went – Auxin