Plant Structure

And Growth

The Plant Body is Composed of

Cells and Tissues

Tissue systems

made up of tissues

made up of cells

Plant Tissue Systems (Functions)

Ground Tissue System

photosynthesis

storage

support

Vascular Tissue System

conduction

support

Dermal Tissue System

Covering

Ground Tissue System

Different types of Ground Tissue

Parenchyma Tissue

Collenchyma Tissue

Sclerenchyma Tissue

Helpful hint: remember which ones

are living or dead at maturity and

which have only a primary wall and

which have a secondary wall)

Parenchyma

Tissue

Made up of Parenchyma

Cells

Living Cells at maturity

Primary Walls

Functions

photosynthesis

storage

Collenchyma

Tissue

Made up of

Collenchyma Cells

Living Cells at

maturity

Primary Walls that are

thickened

Function

Support

Sclerenchyma

Tissue Made up of Sclerenchyma Cells

Usually Dead at maturity

Primary Walls and Secondary

Walls which are thickened with

lignin

There are two types

Fibers (seen in the top picture - red

cells on top and bottom)

Sclerids (seen in the bottom picture)

Function

Support

Vascular Tissue System

Xylem (two types of

cells)

Tracheids

Vessel Elements

Phloem (two types of

cells)

Sieve-tube Members

Companion Cells

Xylem Tracheids

Dead at maturity

They have pits -

water moves

through pits from

cell to cell

Vessel Elements

Dead at maturity

They have

perforations -

water moves

directly from cell

to cell

Phloem Sieve-tube

Members

alive at maturity

lack nucleus at maturity

Sieve plates - on end to transport food

Companion Cells

alive at maturity

helps control sieve-tube member cell

Dermal Tissue System

Epidermis

complex tissue

usually transparent

secretes cuticle

Periderm

replaces epidermis in woody plants

protection

Plant Systems

Root System

Tap Root

Lateral Roots

Shoot System

Stems

Nodes

Internodes

Leaves

blades

petioles

Buds

Terminal (apical)

Axillary

Plant Growth

Meristematic Tissue

generates cells for new growth

apical meristems

lateral meristems

Apical Meristems

increases length called primary growth

Protoderm - gives rise to dermal

tissue

Ground Meristem - gives rise to

ground tissue

Procambium - gives rise to vascular

tissue

Lateral Meristems

increases girth called secondary growth

Vascular Cambium - produces

secondary xylem and secondary

phloem

Cork Cambium - produces cork and

phelloderm

The Root System

Functions

anchor plant

absorb minerals, water and nutrients

store food

Systems

taproots - one large root with smaller

lateral roots (dicots)

fibrous roots - threadlike roots (monocots)

Root Structure

Four Regions

Root Cap - protection

Region of Cell

Division - new cells

Region of Elongation

- cells get longer

Region of Maturation

- cells begin to

specialize

Root Tissue

Protoderm - gives rise to the epidermis

Procambium - gives rise to the stele

xylem and phloem

may include pith

Ground Meristem

Cortex

Monocot vs. Dicot Root You will need to be able to recognize the difference

between a monocot root and a dicot root

Monocot Root (inside to outside)

Pith

Xylem

transport water

Phloem

transport food

Pericycle

dividing cells

Endodermis

Casparian Strip made

of suberin to regulate

water and minerals

Passage Cells to allow

water to pass through

Cortex

storage

Epidermis

protection

Monocot Root

You will need to be able to recognize parts

Epidermis

Cortex

Endodermis (red circle)

Pericycle (one layer inside

the red circle)

Pith

Xylem (red)

Phloem (green)

Dicot Root (inside to outside)

Xylem

transport

water

Phloem

transport

food

Pericycle

dividing

cells

Endodermis

Casparian Strip made

of suberin to regulate

water and minerals

Passage Cells to allow

water to pass through

Cortex

storage

Epidermis

protection

Dicot Root

You will need to be able to recognize parts

Epidermis

Cortex

Endodermis (red circle)

Pericycle (one layer inside

the red circle)

Xylem (red)

Phloem (green)

No pith

Modified Roots

Food Storage

carrots, sweet

potatoes, yams

Modified Roots

Water Storage

manroot, pumpkin

family

Modified Roots

Propagative Roots which

produce adventious buds

cherries, pears

Modified Roots

Pnematophores

Prop Roots

mangroves

Modified Roots

Aerial Roots

orchids, ivies

Modified Roots

Buttress Roots

tropical trees

Modified Roots

Haustoria

dodder

Shoot

System

The Shoot System

Made up of Stems, Leaves, Flowers, Fruits

Stems - support, conduction, growth

Leaves - photosynthesis

Flowers - pollination

Fruits - seed protection, dispersal

Stems (Primary Growth)

Protoderm - gives rise to the epidermis

Procambium - gives rise to the stele

xylem and phloem in vascular

bundles

dicots - found in ring

monocots - scattered throughout

includes pith in dicots

Ground Meristem

Cortex

Vascular Bundle

Parts

Fibers

Phloem

Xylem

Monocot vs. Dicot StemYou will need to be able to recognize the difference

between a monocot stem and a dicot stem

Monocot Stem (Inside to Outside)

Ground Tissue

Vascular Bundles

Xylem

Phloem

Fibers

Cortex

Epidermis

Monocot Stem

You will need to be able to recognize parts

Epidermis

Cortex (very small)

Ground Tissue

Vascular Bundle

Xylem (red)

Phloem (green)

Fiber (red)

Dicot Stem (Inside to Outside)

Pith

Vascular Bundles

Xylem

Phloem

Fibers

Cortex

Epidermis

Dicot Stem

You will need to be able to recognize parts

Epidermis

Cortex

Pith

Vascular Bundle

Xylem (red)

Phloem (green)

Fiber (red)

Roots vs StemsRoots have Endodermis / Stems Vascular Bundles

Monocot

Roots – has pith

Stems – No pith

Vascular bundles in a ring

Dicot

Roots – no pith

Stem – pith

Vascular bundles are

scattered

Stems (Secondary Growth)

Occurs to increase girth (thickness)

Vascular Cambium

produces secondary xylem and phloem

Cork Cambium

produces cork and phelloderm

together these structures are called periderm

Secondary Growth

Secondary Growth

C – Vascular Cambian

D – Differentiated cell

(will turn into another

type of cell)

X – Xylem

P - Phloem

The vascular cambian

goes through mitosis and

creates a cell (D) which on

the inside of the plant

becomes a xylem cell.

The next mitotic division

produces another cell (D)

which is on the outside

and becomes a phloem

cell

Secondary Growth of a Stem

You will

need to know

the parts

Secondary

Growth of

a Stem

Secondary Growth of a Stem

(Inside to Outside)

Pith

Primary

Xylem

Secondary

Xylem

(wood)

Vascular

Cambium

Secondary

Phloem

Primary Phloem

Cortex

Phelloderm

Cork Cambium

Cork

Secondary Growth Periderm is cork cambium

and cork

Bark is everything outside

the vascular cambium

Wood (to a botanist) is

secondary xylem

Sap wood – still moves

water

Heart wood – no

longer moves water,

hardened now used for

support

Modified Stems

Stolons - horizontal

stems above the

ground

Modified Stems

Rhizomes - horizontal

stems below the

ground

Modified Stems

Tubers - swollen areas

of rhizomes

Modified Stems

Bulbs & Corms -

vertical shoots under

the ground

Modified Stems

Cladophylls - cactus

pads

Leaf Structure

Simple leaf – one blade after axillary bud

Compound leaf – multiple blades called leaflets

Double Compound leaf – leaflets broken up into smaller

leaflets

Leaf Structure

Leaves

Epidermis

Stomata - openings on underside of

leaf

Guard Cells - surround stomata

Cuticle - waxy coating excreted by

epidermis

Mesophyll - middle of leaf

Palisade layer - photosynthesis

Spongy layer - gas exchange

Modified Leaves

Needles - reduce water

loss

Modified Leaves

Tendrils - long thin

leaves for clinging

Modified Leaves

Spines - protection

Modified Leaves

Succulents – water

storage