Lab 14 Review: Roots, Stems, and Leaves

Fibrous root system

Roots of similar size with high surface area.

Tap root system

Single large root growing deep for water access.

Root cross-section

Structure comparison between monocot and dicot roots.

Epidermis

Outer layer of root with water-absorbing root hairs.

Cortex

Wide layer storing starch beneath the epidermis.

Endodermis

Inner layer with Casparian strip for water regulation.

Casparian strip

Wax-covered cells directing water to xylem.

Vascular stele

Cylindrical region inside endodermis containing vascular tissue.

Xylem

Tissue transporting water from roots to leaves.

Phloem

Tissue transporting sugars from leaves to roots.

Monocot roots

Xylem and phloem form a ring inside endodermis.

Dicot roots

Xylem has a branched pattern with phloem patches.

Stem cross-section

Structure comparison between monocot and dicot stems.

Vascular bundles

Xylem inside, phloem outside in stem

Monocot stems

Scattered vascular bundles without cortex or pith.

Dicot stems

Vascular bundles arranged in a ring with pith.

Bark

Protective outer layer replacing epidermis in stems.

Vascular cambium

Layer producing new phloem and xylem annually.

Wood

Xylem tissue, functional only in outer ring.

Monocot leaves

Long, narrow leaves with parallel, unbranched veins.

Dicot leaves

Broad leaves with branching venation patterns.

Stomata

Leaf openings for gas exchange, controlled by guard cells.

Mesophyll

Middle leaf layer containing photosynthetic cells.

Palisade mesophyll

Upper layer of densely packed photosynthetic cells.

Spongy mesophyll

Lower layer with spaces for gas exchange.