Transcript Unit 14 Plants PPT

PLANT UNIT
Chapters 23 - 26
“Plant”?
# Cells?
Multicellular
Cell Type?
Eukaryotic
Metabolism?
Structure?
Photosynthetic autrotrophs
made of cellulose and chlorophyll a and b in chloroplasts
Cells walls
Land plants evolved from?
green algae
Four main groups of land plants:
Bryophytes
Pteridophytes
(ferns)
(mosses)
Gymnosperms
(conifers)
Angiosperms
(Flowering plants)
Seed/Flowers
~130 mya
“Vascular” ~400 mya
“Nonvascular” “Seedless”
~550 mya
Seed/Cone
~360 mya
VASCULAR
SEED
PLANTS
Vascular = food and water transport tissue
Seed = embryo packaged along with a food supply within a protective coat
Non-Seed
= Spores
Angiosperms (flowers)
Gymnosperms (cones)
Seeds
Angiosperms
250,000 known species
by far the most diverse and widespread group of land plants
Division Anthophyta
Importance?
Primary Producers
2 main classes: Monocots and Dicots
Monocots
lilies, orchids, yuccas, grasses, and grains
(65,000 species)
Dicots
includes roses, peas, sunflowers, oaks, and maples
(165,000 species)
PLANT STRUCTURE
Basic Morphology
Stem
Leaves
3 Organs?
Roots
Roots?
Anchor
Absorb minerals and water
Store food
Fibrous root systems
Monocots (grasses)
Anchors / + Surface Area
Taproot system
Dicots
Anchor / Store Food
Root hairs
Most absorption of water and minerals
Increase the surface area enormously
Shoots
Stems and Leaves
Nodes = the points at which
leaves are attached
Internodes = the stem segments
between nodes
Terminal bud (apex) = Growth of a young shoot is concentrated
Axillary bud
At the angle formed by each leaf and the stem
potential to form a vegetative branch
Modified shoots
Stolons “runners” grow on the surface (asexual dominance)
Tubers/ Bulbs
for food storage
Rhizomes are horizontal stems that grow underground
Leaves?
main photosynthetic organs
Blade
Petiole = joins the leaf to a
stem node
monocots
?
dicot
Leaves have become adapted by evolution for other functions
tendrils to cling to supports
modified for water storage
spines for defense
brightly colored for
attracting pollinators
Leaf is used to identify and classify plants
simple leaves have a single, undivided blade
compound leaves have several leaflets attached to the petiole
Pinnate
Compound
Simple
Palmate
Compound
Whorled
Shape?
Elliptic
Cordate
Margin?
Serrate
“toothed”
Entire
6
3
4
5
1
7
8
9
10
2
Three tissue types:
Each organ of a plant
-Dermal
-Vascular
-Ground tissue
Each is continuous
throughout the plant body
1. Dermal tissue (epidermis)
covers and protects
“Cuticle”
waxy coating
Upper
Epidermis
Lower
Epidermis
2. Vascular tissue
transport of materials
Phloem
(alive)


Xylem
(dead)
Longitudinal Section
“Vascular Bundle”
Cross Section
3. Ground tissue
Tissue that is neither dermal tissue nor vascular tissue
Function = include photosynthesis, storage, and support
Divided into pith, internal to vascular tissue,
and cortex, external to the vascular tissue
Cortex
Pith
PLANT GROWTH AND
DEVELOPMENT
The Seed
-Embryo
-Seed Coat
-Storage Material (Endosperm or Cotyledons)
Starch (oils and protein)
(Dicot)
Shoot tip
Young leaves
Young shoot
Root
Nutrients
GERMINATION AND DEVELOPMENT
Dormant (upon reaching maturity) until specific environmental cues
are encountered:
-Water
-Temperature
-Light
-Seed coat damage (fire/ digestive tracts)
Water
PLANT GROWTH
Meristems = embryonic tissues in the growth region
2 types of Growth:
1. Primary
2. Secondary
Primary growth
= growth in length
Apical meristems = located at the
tips of roots and in the buds of shoots
“Young” growth
Down – roots
Up - stems
“Primary Root Growth”
Cap = protects the meristem as the root
pushes through the abrasive soil
secretes a
lubricating slime
Primary Shoot Growth

Apical meristem
at the terminal bud
Secondary growth
= progressive thickening/girth
of roots and shoots
Lateral meristems =
cylinders of dividing cells extending
along the length of roots and shoots
“Woody” parts of plants
“Older” growth
Periods of
growth and
dormancy
Annual
Age
and
Rianfall
REPRODUCTION
Four Organs:
Nonreproductive:
Sepals
Petals
Reproductive:
Stamen (male)
Carpel/Pistil (female)
Complete Flower = contains all 4 organs
“Perfect”  Male and Female flower
Incomplete Flower = lacks one or more organs
“Imperfect”  Male or Female flowers
“Pollination”
Wind
Animals:
Bees
Butterflies
Moths
Beetles
Flies
Hummingbirds
Bats
“Radial”
Symmetry
“Bilateral”
Symmetry
Ultraviolet
Suck the nectar
Pollen sticks to its body
Avoid self-fertilization
“Genetic Variability”

Fertilization
Eggs Mature
Ovary Swells
Fruit Develops
Seed
Encased
In
Fruit
Ripens
“Ethylene”
Seeds
Dispersed
PRIMARY STRUCTURE OF ROOTS
Dermal Tissue
Epidermis
Root Hairs
Ground Tissue
Cortex
Endodermis
Vascular Tissue
Xylem/Phloem
Pith
PRIMARY STRUCTURE OF STEMS
Dermal Tissue
Epidermis
Cuticle
Ground Tissue
Cortex (chloroplast)
Pith
Vascular Tissue
Xylem/ Phloem

Cortex
Xylem

Phloem
Pith

Epidermis
STRUCTURE OF THE LEAF
Dermal Tissue
Epidermis
Cuticle
Ground Tissue
Palisade Mesophyll (chloroplast)
Spongy Mesophyll (gas exchange)
Vascular Tissue
Vein
Xylem/ Phloem
Stomata/ Guard Cells
Guard
Cells
Stoma
Root
Leaf
Cortex
Xylem 
Phloem
Pith
Stem
Epidermis
1
2
5
3
4
8
7
6
SECONDARY STRUCTURE OF STEMS
AND ROOTS
The stems and roots, but not the leaves, of
most dicots increase in
girth by secondary growth
The vascular cambium acts as a meristem for the
production of secondary xylem and secondary phloem
Inside = cells differentiate into secondary xylem
Outside = secondary phloem
Vascular
Cambium
Over the years, secondary xylem accumulates and increases the girth of stem/root
In addition, new secondary phloem is added yearly to the outside
As a result, tissues “grow” in
both directions (girth)
Bark refers to all tissues external to the
vascular cambium, including secondary
phloem, cork cambium, and cork
Primary tissues (epidermis/ cortex) are “sloughed off”
Periderm = replace the shed epidermis (protective covering)
Cork Cambium (meristematic)
Cork cells (suberin)
Periderm
Each year new layers of secondary xylem are produced (vascular cambium)
Xylem tissue (wood) is dead at maturity
Sapwood = active xylem
Heartwood = older xylem (support)
Heartwood
Sapwood
Vascular Cambium
Growth –
vascular
cambium active
(new cells)
Dormancy
Growth
Annual ringsSecondary
xylem
tissue
Age
and
Rianfall
TRANSPORT OF WATER
Moves toward the center
of the root by one of
2 pathways:
Water/ dissolved
minerals enter
roots through
root hairs
by osmosis
Apoplast =
Pathway of water moving through cell walls from cell to cell w/o entering the cells
“Nonliving” portion

Symplast =
Cytoplasm from one cell to another through plasmodesmata
“Living” portion

Endodermis  Stele (vascular bundle)  Xylem
Symplast pathway (casparian strip/suberin blocks)
Tracheids
Vessel Elements
Three mechanisms are involved in the movement of water/ dissolved minerals:
1. Osmosis
2. Capillary Action
3. Cohesion-Tension Theory
Life Cycles
• Annual = complete their life cycle in a single year
or less (wildflowers, cereals and legumes)
• Biennial = life spans two years.
– Often, there is an intervening cold period
between the vegetative growth season and the
flowering season.
• Perennials =live many years (trees, shrubs, and
some grasses)
Drupe