Plants IIPlants II

Chapter 30Chapter 30

What you need to know!What you need to know!

Key adaptations to life on land unique to seed Key adaptations to life on land unique to seed plants.plants.

The evolutionary significance of seeds and The evolutionary significance of seeds and pollen.pollen.

The role of flowers and fruits in angiosperm The role of flowers and fruits in angiosperm reproduction.reproduction.

The role of stamens and carpels in angiosperm The role of stamens and carpels in angiosperm reproductionreproduction

SeedsSeeds

Fertilized, embryo-containing female Fertilized, embryo-containing female megaspore, surrounded by nutrients and megaspore, surrounded by nutrients and covered by a seed coat (integument)covered by a seed coat (integument)

Seeds contain high energy nutrients like fats, Seeds contain high energy nutrients like fats, carbs, and proteins to help the new plant carbs, and proteins to help the new plant embryo grow until it has leaves and can do embryo grow until it has leaves and can do photosynthesisphotosynthesis

Remain dormant until favorable conditionsRemain dormant until favorable conditions

Seeds and ReproductionSeeds and Reproduction

Emerged 340 million years agoEmerged 340 million years ago Miniaturization of the gametophyteMiniaturization of the gametophyte HeterosporousHeterosporous Ovum (fruit): protection of delicate, large female Ovum (fruit): protection of delicate, large female

megaspore (drought, UV light)megaspore (drought, UV light) Pollen: male microspores covered by tough Pollen: male microspores covered by tough

membranemembrane Pollination: pollen grain germinates and grows a Pollination: pollen grain germinates and grows a

pollen tube to let sperm reach the ovumpollen tube to let sperm reach the ovum Pollination Pollination fertilization fertilization seed development seed development

Tracheophyta – Seed PlantsTracheophyta – Seed Plants

Class: Gymnosperms Class: Gymnosperms – naked seeds (no – naked seeds (no fruit), and flowerlessfruit), and flowerless Ginko and Conifers Ginko and Conifers

(pines and firs)(pines and firs) Pollen cones (sperm) Pollen cones (sperm)

and ovule cones and ovule cones (eggs)(eggs)

Wind is primary Wind is primary pollinatorpollinator

Seeds grow in conesSeeds grow in cones

Tracheophyta – Seed PlantsTracheophyta – Seed Plants

Class Angiosperm – flowering, fruit producing Class Angiosperm – flowering, fruit producing plantsplants Subclass: monocot (single seed leaf)Subclass: monocot (single seed leaf) Subclass: dicots (double seedleaf)Subclass: dicots (double seedleaf)

LeavesLeaves flattened bladeflattened blade Main photosynthetic organsMain photosynthetic organs

FlowersFlowers

FlowersFlowers

Specialized Cells in PlantsSpecialized Cells in Plants

1.1. ParenchymaParenchyma No cell wallsNo cell walls Carry out most of metabolismCarry out most of metabolism Few cellular divisions once matureFew cellular divisions once mature

2.2. CollenchymaCollenchyma No cell wallNo cell wall Strength and support in young cellsStrength and support in young cells

3.3. SclerenchymaSclerenchyma Thick cell wallsThick cell walls Carry lignin (wood forming substance)Carry lignin (wood forming substance) Lose protoplast (cellular innards) when matureLose protoplast (cellular innards) when mature

StemsStemsXylemXylem HH22O and mineralsO and minerals Thick cell wallsThick cell walls Lose protoplast when matureLose protoplast when mature Transport of water up to 15 m/h or moreTransport of water up to 15 m/h or more Only one way direction root Only one way direction root top top Driven by water potential (vacuum)Driven by water potential (vacuum)PhloemPhloem Transport of sugar, AA, ionsTransport of sugar, AA, ions Sieve tubes between cells with protoplastSieve tubes between cells with protoplast Transport in any directionTransport in any direction Positive pressure flow mechanism (diffusion/osmosis)Positive pressure flow mechanism (diffusion/osmosis) Sugars are transported from sugar source (leaves) to sugar Sugars are transported from sugar source (leaves) to sugar

sinks (starch stores)sinks (starch stores)

UptakeUptake

Minerals enter into root cells (active transport)Minerals enter into root cells (active transport) Water enters into root cells (osmosis)Water enters into root cells (osmosis) Transpirational pull upward to tip of plant Transpirational pull upward to tip of plant

(water potential vacuum)(water potential vacuum) Cohesion and adhesion of water to cell wallsCohesion and adhesion of water to cell walls

Photosynthesis & Transpiration Photosynthesis & Transpiration CompromiseCompromise

Stomata surrounded by guard cellsStomata surrounded by guard cells Regulate transpiration and gas exchangeRegulate transpiration and gas exchangeOpen: + transpiration / + gas exchangeOpen: + transpiration / + gas exchange Sufficient turgor =Sufficient turgor = Influx of potassium followed by waterInflux of potassium followed by water Swelling of guard cellsSwelling of guard cells Opening of stomataOpening of stomataClosed: - transpiration / - gas exchangeClosed: - transpiration / - gas exchange Insufficient turgor =Insufficient turgor = Outflux of potassium and waterOutflux of potassium and water Shrinking of guard cellsShrinking of guard cells Closing of stomataClosing of stomata

Plant AnatomyPlant Anatomy Primary growth Primary growth

= UP= UP Secondary Secondary

Growth = OUTGrowth = OUT

Monocots and Dicots (Eudicots)Monocots and Dicots (Eudicots)

MonocotsMonocots DicotsDicots

Cotyledons (seed leaves):Cotyledons (seed leaves): 11 22

Leave veins:Leave veins: parallelparallel netlikenetlike

Vascular tissue:Vascular tissue: scatteredscattered ringring

Roots:Roots: fibrousfibrous taproottaproot

Photosynthesis:Photosynthesis: C4C4 C3C3

Flower organs:Flower organs: X 3X 3 X 5X 5

Monocots and Dicots (Eudicot)Monocots and Dicots (Eudicot)