Transcript Unit 2c Lecture Notes - Mt. SAC Faculty Directory

Plant Structure
And Growth
The Plant Body is
Composed of Cells and
Tissues
•Tissue systems (Like Organs)
–made up of tissues
•Made up of cells
Plant Tissue Systems
Ground Tissue System
• ____________________
photosynthesis
storage
support
Vascular Tissue System
• ____________________
conduction
support
Dermal Tissue System
• ___________________
Covering
Ground Tissue System
Parenchyma Tissue
• ___________
• Collenchyma Tissue
• Sclerenchyma Tissue
Parenchyma
Tissue
• Made up of
Parenchyma Cells
Living
• __________
Cells
• Primary Walls
• Functions
– photosynthesis
– storage
Collenchyma
Tissue
• Made up of
Collenchyma Cells
• Living Cells
• Primary Walls are
thickened
• Function
– _Support_____
Sclerenchyma
Tissue
• Made up of
Sclerenchyma Cells
• Usually Dead
• Primary Walls and
secondary walls
that are thickened
(lignin)
Fibers
• _________
or
Sclerids
_________
• Function
– Support
Vascular Tissue System
• Xylem – H2O
Tracheids
– ___________
– Vessel Elements
• Phloem - Food
– Sieve-tube
Members
Companion
– __________
Cells
Xylem
• Tracheids
– dead at maturity
– pits - water
moves through
pits from cell to
cell
• Vessel Elements
– dead at maturity
– perforations water moves
directly from cell
to cell
Phloem
Sieve-tube member
Companion Cell (on
the side)
members
• Sieve-tube
_____________
– alive at
maturity
– lack nucleus
– Sieve plates on end to
transport food
Companion Cells
• _____________
– alive at
maturity
– helps control
sieve-tube
member cell
Dermal Tissue System
• Epidermis
– Single layer, tightly packed cells
– Complex Tissue – Does different
things in different areas (roots vs.
leaves)
– usually transparent
– secretes cuticle
Periderm
• ___________
–
– replaces epidermis in woody plants
– protection
Root System
• ____________
– Tap Root
– Lateral Roots
Shoot System
• ____________
– Stems
• Nodes (leaves
are attached)
• Internodes
– Leaves
• blades
• petioles
– Buds
Plant
Systems
• Terminal
(apical)
• Axillary
Plant Growth
Meristematic
• ______________
Tissue
–generates cells for new
growth (like stem cells in
animals)
•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 (outer most layer of bark)
Pine Tree w/ 8 Cotyledons!
The Root System
• Functions
– anchor plant
– absorb minerals, water and
nutrients
– store food
• Systems
Tap roots
– ____________
- one large root
with smaller lateral roots (dicots)
Fibrous roots threadlike roots
– ____________(monocots)
Root Structure
• Four Regions
Root Cap
–_________–
protection, also
secrete polysaccharide slime to
lubricate
Cell Division
–Region of ___________new
cells
Elongation
–Region of __________
- cells
get longer
Maturation - cells
–Region of _________
begin to specialize
Root Tissue
• Protoderm - gives rise to the
epidermis
• Ground Meristem
– Cortex (external to vascular
tissue)
• Procambium - gives rise to the
Stele (the vascular tissue of a
_______
root or stem)
– xylem and phloem
– may include pith (parenchyma
cells surrounded by vascular
tissue)
Dicot Root vs. Monocot
Xylem
(larger, in
red)
Endodermis
Phloem
(smaller,
greenish)
Pericycle – one layer IN
from endoderm, gives
rise to lateral roots
“Pith” – central core of
parenchyma cells
surrounded by xylem and
phloem
Modified Roots
• Food Storage
– carrots, sweet
potatoes, yams
• Water Storage
– pumpkin family
• Propagative
Roots
– cherries, pears
• Pnematophores
– mangroves
• Aerial Roots
– orchids
• Buttress Roots
– tropical trees
• 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
____________
– stele (vascular tissue)
divided into strands in
stems and leaves
Sclerenchyma
cells
Phloem
Xylem
Dicot Stem Vs. Monocot (35.16)
Vascular Bundle
Ground Tissue
(Pith)
(Cortex)
How can you tell root from stem?
Stems (Secondary Growth)
• Occurs to increase girth
(thickness)
– Vascular Cambium
• produces secondary xylem and
secondary phloem
– Cork Cambium
• produces cork and phelloderm
(thin layer of parenchyma cells)
• together these structures are called
periderm (Cork Cambium, cork,
phelloderm)
Secondary Growth
Derivative
Vascular cambium
Secondary
Growth of
a Stem
• Pith
• Primary
Xylem
• Secondary
Xylem
(wood)
• Vascular
Cambium
Periderm
Secondary Growth of a
Stem (Inside to Outside)
• Secondary
Phloem
• Primary
Phloem
• Cortex
• Phelloderm
• Cork Cambium
• Cork (outer
layer of bark)
Older, inner layers
of 2° Xylem – no
longer transport
water
Younger, outer
layers of 2°
Xylem still
function in
transport
All tissue
outside
vascular
cambium
Missing cortex and phelloderm!
Springwood
___________
(Early) growth
occurs more
quickly. Cells are large and thin
walled and have less strength.
Summerwood (Late) growth
occurs more slowly. Cells are
thicker, more dense, and stronger.
Secondary
Growth of
a Stem
Modified Stems
Stolons - horizontal
• __________
stems above the ground
(strawberries)
• Rhizomes - horizontal
stems below the ground
(Irises)
• Tubers - swollen areas of
rhizomes or stolons
(Potatoes)
• Bulbs & Corms - vertical
shoots under ground
(onions, garlic w/ mod
storage leaves)
Cladophylls
• _____________
cactus pads
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
Tendrils
• ___________attachment
• Bracts –modified
leaves that
surround a group
of flowers
• Spines protection
• Storage Leaves
- succulents