Plant Form Function Plant Anatomy AP Biology Tissues

Plant Form & Function Plant Anatomy AP Biology

Tissues make up the plants organs • Roots • Stems • Leaves

Plant Tissues • Dermal Tissue • Epidermis – Cover surface of plant – Guard cells-

Plant Tissues • Ground tissues • Parenchyma – Thin walls – Storage – Photosynthesis – Secretion

Plant Tissues • Ground tissues • Collenchyma – Thick, flexible walls – Support

Plant Tissues • Ground tissues • Sclerenchyma – Thick walls – Support

Plant Tissues • Vascular Tissue • Phloem – Transports food – Sieve-tube members – Companion cells

Plant Tissues • Vascular Tissue • Xylem – Transports water & minerals – Tracheids – Vessel elements

Primary vs. Secondary Growth • • Primary Growth in length Apical meristems Tips of roots & shoots

Primary vs. Secondary Growth • • • Secondary Growth in width Lateral meristems Vascular cambium Cork cambium

Root Tip • Root cap • Protects apical meristem

Root Tip • Zone of cell division • Cells divide • Apical meristem

Root Tip • Zone of elongation • Cells absorb water & elongate

Root Tip • Zone of maturation • Cells mature • Perform specific functions • Cells differentiate • Root hairs

Herbaceous Dicot Stem • Epidermis • Outer layer of cells • Provides protection

Herbaceous Dicot Stem • Cortex • Ground tissue • May contain chloroplasts

Herbaceous Dicot Stem • Pith • Storage • Provides support through turgor pressure

Herbaceous Dicot Stem • Vascular Bundle • Xylem & phloem • Occur in rings

Herbaceous Dicot Stem • Vascular Bundle • Bundle cap • Cells – Dead – Fibrous – Thick walled • Sclerenchyma cells • Provide support

Herbaceous Dicot Stem • • Vascular Bundle Phloem Transports food Sieve-tube members – Long – Living cells • Companion cells – Small – Parenchyma cells

Herbaceous Dicot Stem • • Vascular Bundle Xylem Transports water Tracheids – Dead – Thick walled • Vessel elements – Large diameter – Dead

Herbaceous Dicot Stem • Vascular Bundle • Vascular cambium • Between xylem & phloem • Cells divide to form xylem & phloem

Woody Stem • Pith

Woody Stem • Xylem • Wood

Woody Stem • Xylem • Wood • Summer wood – Small cells – Less water • Spring wood – Large cells – More water

Woody Stem • • • Xylem Annual rings 1 st year’s growth 2 nd year’s growth 3 rd year’s growth

Woody Stem • Bark • Phloem • Cortex

Woody Stem • Vascular cambium • Between xylem & phloem • Produces new xylem & phloem cells • Secondary growth

Dicot Root Cross Section • Epidermis • Absorbs water • Root hairs increase surface area for water absorption • In older roots provides protection

Dicot Root Cross Section • Cortex • Bulk of root • Stores starch

Dicot Root Cross Section • • Vascular cylinder Stele Xylem & phloem Outlined by endodermis

Dicot Root Cross Section • • • Vascular cylinder Xylem Large cells Dead Transport water & minerals

Dicot Root Cross Section • • Vascular cylinder Phloem Small cells Transport food

Dicot Root Cross Section • Vascular cylinder • Endodermis • Casparian strip – Waxy – Forms barrier • All water must pass through endodermis before entering stele

Leaf • Upper epidermis • Provides protection • Cuticle – Waxy – Decreases water loss

Leaf • Lower epidermis • Contains stomata – Holes – Allow CO 2 in & O 2 & H 2 O out – Surrounded by guard cells

Leaf • Palisade mesophyll • Parenchyma cells • Tightly packed • Photosynthesis

Leaf • Spongy mesophyll • Parenchyma cells • Loosely arranged • Photosynthesis • Air spaces

Leaf • Vascular bundle • Veins • Xylem (red) & phloem (green) • Bundle sheath cells surround bundles