PLANT UNIT
Chapters 29-30, 35-39
-Evolution
-Structure and Growth
-Transport
-Nutrition
-Reproduction
-Responses
EVOLUTION
Land Plants
Spores  Seeds
Alternation of Generations
Water Management
Vascular Tissue
Xylem Cell Evolution
Secondary Compounds
Bryophytes
Pteridophytes
Gymnosperms
Angiosperms
Monocot
and
Dicot
PLANT STRUCTURE
Leaf
Stem
Root
3 Tissues:
-Ground
-Dermal
-Vascular
Ground Tissue (thickness of cell wall)
Thinnest  Thickest
1.Parenchyma Cells = storage, photo, secretion
2.Collenchyma Cells = mechanical support
3.Sclerenchyma Cells = mechanical support
Dermal Tissue
Epidermal cells, guard cells/stomata, specialized cells (hair cells, stinging cells, glandular cells)
Alkyl Groups (C-H)
C6H4(OH)2
Urushiol oil
R = (CH2)14CH3 or
R = (CH2)7CH=CH(CH2)5CH3 or
R = (CH2)7CH=CHCH2CH=CH(CH2)2CH3 or
R = (CH2)7CH=CHCH2CH=CHCH=CHCH3 or
R = (CH2)7CH=CHCH2CH=CHCH2CH=CH2
Vascular Tissue
Xylem = transport water and minerals, provide mechanical support
Phloem = transport sugar
Xylem
Vascular
Bundles
Tracheids
Vessel Elements
Secondary Cell Wall = Strength
Dead at maturity (no components)
Phloem
Sieve-Tube Members
Sieve-Tubes
Plasmodesmata
Perforations =
more efficient
Living at maturity
No Nuclei or Ribosomes
Companion Cell =parenchyma cell that provides
physiological support to sieve-tube member
PLANT GROWTH
The Seed
Seed Coat
Embryo
Endosperm or
Cotyledons (digested endosperm)
Epicotyl (shoot tip)
Radicle (root)
Hypocotyl (shoot)
Plumule (leaves)
Cotyledon
Seed to Seedling
SAM (Shoot Apical Meristem)
Negative Gravitropism
Dormancy = environmental cues
(water, temp, light, fire, ingestion)
Imbibition (absorption) of water
Initiates enzymes  biochemical pathways
Seed coat swells and cracks
Radicle  Hypocotyl elongation
RAM (Root Apical Meristem)
Water  Gibberellins (GA) hormones  Aleurone (outer endosperm)  Amylase  Growth
Positive Gravitropism (Auxin)
Xylem/ Pholem
Parenchyma
Epidermal
Differentiation
PRIMARY GROWTH vs. SECONDARY GROWTH
Primary Growth
- vertical growth
-apical meristems
Secondary Growth
-lateral growth (girth)
-lateral meristems
-“cambium”
Primary Structure
of Roots
Casparian Strip (Suberin/wax)
Lateral Root from Pericycle
Primary Structure
of Stems
Cutin (wax)
Secondary Structure
of Stems
Primary Structure
of Leaves
Cutin (waxy)
TRANSPORT IN PLANTS
Xylem Sap Transport (Evapotranspiration)
Only Symplast
Nitrates
Cohesion-Tension Theory (most water movement)
-transpiration (negative pressure/ tension in leaves)
-cohesion (hydrogen bonds between water)
-bulk flow (evaporation from leaf pulls the column)
Capillary Action
-rise of liquids in narrow tubes
-adhesion
Into Xylem = “Root Pressure”
- seen in “guttation”
Into root = Osmosis
-movement of water root  stem
-mineral concentration in stele
Leaf Draw (Pull)
Guard Cells
-cell walls not uniform thickness
-cellulose microfibrils arrranged radially
-water diffuses in
-thinner cell wall expands more
-create the stoma (opening)
Stomata open at dawn – dusk
Three cues:
1. Light stimulates guard cells to accumulate
K+ ions (blue light receptors  H+ pump)
Light drives photosynthesis making ATP
available
2. Depletion of CO2 in air spaces of the leaf
3. “Internal clock” in guard cells
Circadian rhythm
K+ Ions
-active uptake (H+ membrane potential)
-water potential change
TRANSLOCATION OF PHLOEM SAP
Source – Sink (Pressure Flow)
1. Soluble carbohydrates (sucrose)
Palisade mesophyll (source)  Sieve-tube
Active transport
2. Solute concentration gradient
Water diffuses into sieve-tube
3. Pressure potential increases
Bulk flow through sieve-tubes
4. Pressure begins to build at sink
Carbohydrates are being utilized at sink
Sugars removed from sieve-tube (active)
Decrease solute concentration
Water diffuses out relieving the pressure
apoplast
Loading of sucrose into phloem
symplast
Transpiration Adaptations
Xerophytic Leaf
(sunken stoma)
C4 and CAM Adaptations
Plant Nutrients
Flower Reproduction
Pollination
UV light
Fruits
Seed Development
Seed Dispersal
Seedling Growth
Ecological
Impact
Agriculture
And
Medicinal Use
Human Abuse
Deforestation
Plant Responses
(Hormones) Plant Hormone Overview