PLANT UNITChapters 29-30, 35-39

-Evolution-Structure and Growth-Transport-Nutrition-Reproduction-Responses

EVOLUTION

Land Plants

Spores Seeds

Alternation of Generations

Water Management

Xylem Cell Evolution

Vascular Tissue

Secondary Compounds

Bryophytes

Pteridophytes

Gymnosperms

Angiosperms

Monocot and Dicot

PLANT STRUCTURE

3 Tissues: -Ground -Dermal -Vascular

Root

Stem

Leaf

Ground Tissue (thickness of cell wall)Thinnest Thickest1.Parenchyma Cells = storage, photo, secretion2.Collenchyma Cells = mechanical support3.Sclerenchyma Cells = mechanical support

Dermal TissueEpidermal cells, guard cells/stomata, specialized cells (hair cells, stinging cells, glandular cells)

Urushiol oil

C6H4(OH)2R = (CH2)14CH3 orR = (CH2)7CH=CH(CH2)5CH3 orR = (CH2)7CH=CHCH2CH=CH(CH2)2CH3 orR = (CH2)7CH=CHCH2CH=CHCH=CHCH3 orR = (CH2)7CH=CHCH2CH=CHCH2CH=CH2

Alkyl Groups (C-H)

Vascular TissueXylem = transport water and minerals, provide mechanical supportPhloem = transport sugar

Xylem

Secondary Cell Wall = StrengthDead at maturity (no components)

Perforations =more efficient

Phloem

TracheidsVessel Elements

Sieve-Tube MembersSieve-Tubes

Living at maturityNo Nuclei or Ribosomes

Plasmodesmata

Companion Cell =parenchyma cell that providesphysiological support to sieve-tube member

VascularBundles

PLANT GROWTH The Seed Embryo

Seed CoatEndosperm orCotyledons (digested endosperm)

Epicotyl (shoot tip)

Plumule (leaves)

Hypocotyl (shoot)Radicle (root)

Cotyledon

Dormancy = environmental cues (water, temp, light, fire, ingestion)

Imbibition (absorption) of waterInitiates enzymes biochemical pathwaysSeed coat swells and cracksRadicle Hypocotyl elongation

Water Gibberellins (GA) hormones Aleurone (outer endosperm) Amylase Growth

SAM (Shoot Apical Meristem)

RAM (Root Apical Meristem)

Differentiation

Xylem/ PholemParenchymaEpidermal

Seed to SeedlingNegative Gravitropism

Positive Gravitropism (Auxin)

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 Structureof Stems

Cutin (wax)

Secondary Structure of Stems

Primary Structureof Leaves

Cutin (waxy)

TRANSPORT IN PLANTS

Only Symplast

Nitrates

Xylem Sap Transport (Evapotranspiration)

Into root = Osmosis-movement of water root stem-mineral concentration in stele

Into Xylem = “Root Pressure”- seen in “guttation”

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

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)

K+ Ions-active uptake (H+ membrane potential)-water potential change

Stomata open at dawn – duskThree cues:1.Light stimulates guard cells to accumulate K+ ions (blue light receptors H+ pump) Light drives photosynthesis making ATP available2. Depletion of CO2 in air spaces of the leaf3. “Internal clock” in guard cells Circadian rhythm

Loading of sucrose into phloem

symplast

apoplast

TRANSLOCATION OF PHLOEM SAP

Source – Sink (Pressure Flow)1.Soluble carbohydrates (sucrose)

Palisade mesophyll (source) Sieve-tube Active transport2. Solute concentration gradient

Water diffuses into sieve-tube3.Pressure potential increases

Bulk flow through sieve-tubes4.Pressure begins to build at sink

Carbohydrates are being utilized at sink

Sugars removed from sieve-tube (active)

Decrease solute concentrationWater diffuses out relieving the

pressure

C4 and CAM Adaptations

Transpiration Adaptations

Xerophytic Leaf (sunken stoma)

Plant Nutrients

Flower Reproduction

UV light

Pollination

Fruits

Seed Development

Seed Dispersal

Seedling Growth

Ecological Impact

AgricultureAndMedicinal Use

Deforestation

Human Abuse

Plant Hormone Overview

Plant Responses (Hormones)