1. Tutorial: Plants Kingdom: Plants Domain Eukarya Domain Bacteria
Archaea
Eukarya
Common ancestor

2. The first plants
For more than 3 billion years, Earth’s terrestrial surface was lifeless
life evolved in the seas
1st photosynthetic plant organisms were aquatic green algae (charophytes/chlorophytes)
special adaptations for life on dry land
protection from drying = desiccation
waxy cuticle
gas & water vapor exchange (through cuticle)
stomates
water & nutrient conducting systems
xylem & phloem
protection for embryo
seeds

3. Plant Diversity Bryophytes non-vascular land plants
Pteridophytes seedless vascular plants
Gymnosperm pollen & “naked” seeds
Angiosperm flowers & fruit
conifers
flowering plants
mosses
ferns
seedless plants
seed plants
non-vascular plants
vascular plants
colonization of land

4. Flowers - fruit w/ seeds
Plant Classification
Bryophytes
Pteridophytes
Tracheophytes
Gymnosperm
Conifer
Angiosperm
Non-vascular
Vascular
seedless
seeds
Spores &
Haploid Gameotophyte
Cones - naked seeds
Flowers - fruit w/ seeds
Swimming sperm
Pollen & Seeds
Mosses, liverworts
Ferns
Pine, Spruce, Redwood
Lily, Maple, Oak, Rose

5. Vascular tissue Transports materials in roots, stems & leaves Xylem
carry water & minerals up from roots
tube-shaped dead cells
only their walls provide a system of microscopic water pipes
Phloem
carry nutrients throughout plant
sugars (sucrose), amino acids…
tube-shaped living cells
Xylem = Dead cells at maturity = sclerenchyma
Phloem = Alive at maturity - collenchyma

6. Alternation of generations
Fern gametophyte (1n)
small haploid plant which produces gametes
homospory: male & female on same plant
archegonia
antheridia

7. Flower Modified shoot with 4 rings of modified leaves sepals petals
stamens
male
carpel
female
Anther
Filament
Stamen
Stigma
Style
Ovary
Carpel
Sepal
Petal
Ovule
sepals
petals
stamens
carpel

8. Fertilization in flowering plants
Double fertilization
2 sperm from pollen
1 sperm fertilizes egg = diploid zygote (n+n = 2n)
1 sperm fuses with 2 polar nuclei to form endosperm (n+2n = 3n)
endosperm = food tissue in seed
Polar
nuclei
Egg
cell
Pollen grains

9. Seed & Plant embryo seed coat endosperm cotyledons embryo
Seed offers…
protection for embryo
stored nutrients for growth of embryo
Embyonic leaves, shoot, and root
endosperm
cotyledons
embryo
endosperm = “food” storage for developing plant until it can begin making its own.
epicotyl
cotyledons = “seed” leaves,
first leaves of new plant
radicle

10. Preventing self-pollination
Various mechanisms
stamens & carpels may mature at different times
arranged so that animal pollinator won’t transfer pollen from anthers to stigma of same flower
biochemical self-incompatibility = block pollen tube growth

11. Co-evolution: flowers & pollinators
How a bee sees a flower…insects see UV light = a bulls-eye to the nectar

12. Leaf Anatomy (structure)1
Guard Cells 6 5 2
Stoma 3 3
Palisade Layer 4 7 4
Spongy Layer 9 8 5
Upper Epidermis 1 2 6
Cuticle 7
Lower Epidermis 8
Xylem 9
Phloem

13. Root Structure Epidermis: skin covering
Root Hairs: extend out from the root
Root Cap - at the tip of the root, produces a slimy substance
Xylem
Phloem
Vascularization:
1. Phloem - food to the floor
2. Xylem - water up

14. Rise of water in a tree by bulk flow
Transpiration pull
adhesion & cohesion
H bonding
brings water & minerals to shoot
Water potential
high in soil  low in leaves
Root pressure push
due to flow of H2O from soil to root cells
upward push of xylem sap
The transpiration–cohesion–tension mechanism that transports xylem sap against gravity is an excellent example of how physical principles apply to biological processes. In the long–distance transport of water from roots to leaves by bulk flow, the movement of fluid is driven by a water potential difference at opposite ends of a conduit. In a plant, the conduits are vessels or chains of tracheids. The water potential difference is generated at the leaf end by transpirational pull, which lowers the water potential (increases tension) at the “upstream” end of the xylem.
On a smaller scale, water potential gradients drive the osmotic movement of water from cell to cell within root and leaf tissue. Differences in both solute concentration and turgor pressure contribute to this short–distance transport. In contrast, bulk flow depends only on pressure. Another contrast with osmosis, which moves only water, is that bulk flow moves the whole solution, water plus minerals and any other solutes dissolved in the water.
The plant expends no energy to lift xylem sap by bulk flow. Instead, the absorption of sunlight drives transpiration by causing water to evaporate from the moist walls of mesophyll cells and by lowering the water potential in the air spaces within a leaf. Thus, the ascent of xylem sap is ultimately solar powered.

15. Plant Responses Tropism - growth in response to a stimulus
1. Phototropism -
• change in plant growth caused by light (plants bend toward light)
2. Photoperiodism-
• developmental responses of
plants to the relative lengths of
light and dark periods.
3. Gravitropism -
• change in plant growth in response to the direction
of gravity (plants bend up, away from gravity)
4. Thigmotropism -
• growth in response to touch or contact
(plants bend along or around objects)

16. Plant Responses - Seasonal changes in leaves
1. Evergreen - they gradually shed some of their leaves    
         throughout the year, and as a result, maintain leaves year-round.
2. Deciduous - lose all their leaves at once, usually for winter.
What classification of plants are they?
In what biome would you find them?
As chlorophyll productiveness declines with the cool temperatures of autumn, the dominant green color fades, displaying the yellows, oranges, and reds of the accessory pigments.
Colors of the rainbow: R O Y G B I V
accessory pigments: xanthraphyll (yellow) and carotenoids (reds and oranges)
cannot transfer light energy directly to the photosynthetic pathway, they must pass their absorbed energy to chlorophyll. If chlorophyll is rendered ineffective, the energy does not get passed on, therefore, food is not being made, and consequently the leaves will die.
Abscission - shedding of leaves, fruits, flowers
Senscence - dieing off of the plant or plant parts