4B: Plant Structure

Plant Cell Types

Parenchyma Sclerenchyma Collenchyme

Coleus stem tip

Dicot & Monocot Stem X section

Ground meristem

Pith

Procambium

Xylem

Phloem

Protoderm

Apical meristem

Leaf primordial

Axillary bud

Monocot stem

Dicot stem

Vascular Bundle (Xylem & Phloem)

Phloem

Sclerenchyma

Ground meristem

Xylem

Sieve Tube Member Companion Cell

Phloem Sclerenchyma

Cap

Xylem

Vascular cambium btn xylem & phloem

Secondary Growth – herbaceous stems

Hardwood (angiosperm vessel elements) vs softwood (gymnosperms tracheids)

Modified stems:

Rhizome stolons

bulbs tubers

Heartwood (inner xylem)

Sapwood (outer xylem)

ROOTS

Dicot root Monocot Root

Cortex

Epidermis

Vascular Cylinder/Stele

Phloem

Xylem

Pericycle

Root cap

Quiescent center

Apical meristem

Zone of Cell Division

Root types

Taproot (dicot) Fibrous (monocot) Adventitious root

Lateral roots

LEAVES

Leaf epidermis

Guard cells

Stomata

Dicot leaf

Monocot leaf

Palisades Parenchyma

Spongy Parenchyma

Midrib

Upper epidermis (Thicker)

Lower epidermis (Thinner)

Xylem

Phloem

Vascular bundles

Phloem

Xylem

Guard cells

Stomata

Leaf Venation

Parallel venation (monocot) Pinnate venation (dicot) Palmate venation (dicot)

Leaf structure

Simple vs Compound leaves look for the axillary buds

Pinnately Compound leaf Palmately Compound leaf

Pinnately Palmately

Leaf Arrangement

Alternate Opposite Whorled

Modified leaves

Spines Tendrils

Monocots- one cotyledon (seed leaf), vascular bundles scattered in the pith, flower parts in threes, leaves with parallel venation Dicots- two cotyledons, vascular bundles in a ring, flower parts in4’s, 5’s, or multiples, leaves with net venation

Axillary bud