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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
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