PLANT UNIT Chapters 29-30, 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  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) Urushiol oil C 6 H 4 (OH) 2 R = (CH 2 ) 14 CH 3 or R = (CH 2 ) 7 CH=CH(CH 2 ) 5 CH 3 or R = (CH 2 ) 7 CH=CHCH 2 CH=CH(CH 2 ) 2 CH 3 or R = (CH 2 ) 7 CH=CHCH 2 CH=CHCH=CHCH 3 or R = (CH 2 ) 7 CH=CHCH 2 CH=CHCH 2 CH=CH 2 Alkyl Groups (C-H)

Vascular Tissue Xylem = transport water and minerals, provide mechanical support Phloem = transport sugar Xylem Secondary Cell Wall = Strength Dead at maturity (no components) Perforations = more efficient Phloem Tracheids Vessel Elements Sieve-Tube Members Sieve-Tubes Living at maturity No Nuclei or Ribosomes Plasmodesmata Companion Cell =parenchyma cell that provides physiological support to sieve-tube member Vascular Bundles

PLANT GROWTH The Seed Embryo Seed Coat Endosperm or Cotyledons (digested endosperm) Epicotyl (shoot tip) Plumule (leaves) Hypocotyl (shoot)Radicle (root) Cotyledon

Dormancy = environmental cues (water, temp, light, fire, ingestion) Imbibition (absorption) of water Initiates enzymes  biochemical pathways Seed coat swells and cracks Radicle  Hypocotyl elongation Water  Gibberellins (GA) hormones  Aleurone (outer endosperm)  Amylase  Growth SAM (Shoot Apical Meristem) RAM (Root Apical Meristem) Differentiation Xylem/ Pholem Parenchyma Epidermal Seed to Seedling Negative 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 Structure of Stems Cutin (wax)

Secondary Structure of Stems

Primary Structure of 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 – 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 CO 2 in air spaces of the leaf 3. “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 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

C 4 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

Agriculture And Medicinal Use

Deforestation Human Abuse

Plant Hormone Overview Plant Responses (Hormones)