1. Plant Nutrition and Transport
Chapter 21
Plant Nutrition and Transport

2. 21.1 Nutrients from Soil and Air
Experiments
Aristotle - soil provides substance
Van Helmont - water provides
substance (mass)
Willow tree
Hales - air provides substance
Air = CO2 --> photosynthesis --> sugars
Water = H2O --> H - photosynthesis
Solvent for other molecules
80-85% of mass
Soil = inorganic minerals

3. Minerals 17 chemical elements needed Macronutrients; large quantities
3 are not minerals; C, O, H
Macronutrients; large quantities
Nitrogen - protein and NA synthesis
Sulfur - protein synthesis
Phosphorus - NA and ATP synthesis
Potassium -protein syn. & osmosis regulation
Calcium - cell wall formation & enzyme activity
Magnesium - chlorophyll synthesis & enzyme activity

4. Other Minerals Micronutrients (small quantities)
Boron; Essential for seed and fruit development
Copper: carbohydrate and nitrogen metabolism
Iron; Essential for formation of chlorophyll
Chloride: salt effects (stomatal opening
Manganese: formation of chlorophyll; catalyst
Molybdenum: nitrogen and sulfur metabolism, protein synthesis
Zinc: catalyst and regulator; energy production, protein synthesis, growth regulator

5. Nitrogen Produce proteins, nucleic acids, and hormones
Usually deficient
80% of atmosphere (N2)
Plants can only absorb NH4 or NO3
N2 to NH4
NH4 to NO3
break down organic material into ammonia (NH4)

6. Nitrogen-fixing Bacteria
Legumes: peas, beans, peanuts
root nodules: NF bacteria on roots
Mutualistic
Bacteria fix (convert) nitrogen
Plant provides carbohydrates
Crop rotation
Soybeans have NF bacteria
Convert tons of nitrogen
Corn depletes nitrogen

7. Fertilizers Synthetic Plant doesn’t store nutrients
Nitrogen
Phosphorus
Potassium
Plant doesn’t store nutrients
Leftovers are in soil and can contaminate runoff water
Polluted water goes into rivers and lakes

8. Do Now Questions
How does transpiration allow water to flow in a plant?
What is a sugar sink?
Why does a carnivorous plant need to eat insects?

9. 21.2 Vascular Tissue Roots absorb water and minerals
root hairs: tiny outgrowths of root’s epidermal cells
Increase surface area
root pressure: helps push water through xylem; usually at night
Minerals move through the cells to xylem; cytoplasmic channels
endodermis: waxy layer of cells surrounding the vascular tissue
Prevents water and mineral leakage
Water enters by osmosis

10. Water Movement
transpiration: loss of water through leaves due to evaporation, generates the pull of sap upward
Cohesion -
water sticking to
itself
Adhesion -
unlike molecules;
cellulose in xylem

11. Regulating Water Loss Transpiration Stomata regulate transpiration
Upward transport
Evaporative cooling
Water loss from plant
Maple Tree = 220L per hour in the summer
Stomata regulate transpiration
guard cells: cells around each stoma that open and close by changing shape

12. Stomata Day = open to allow CO2 in Night = closed
Low CO2 = K accumulation; water flows in and swell the guard cells
Night = closed

13. 2 Types of Xylem tracheids: long cells with tapered ends
vessel elements: wider and shorter
Form tubes; inner cells died and left lignified cell walls

14. Phloem Transports sucrose and other organic compounds with water
sieve-tube members: chain of cells in which phloem sap flows
Remain alive, but lose nuclei and other organelles
companion cells: cells alongside sieve tubes that provides proteins

15. Sugar Sink
Phloem moves sugar from where it is made (leaves) to where it is needed
Sugar sink: sugar stored or used
Fruits
Roots
Shoot tips
Summer - beat, potatoes

16. Pressure-flow Sugar is actively transported into a sieve-tube member
pressure-flow mechanism: water flows from high pressure to low

17. Monocots
Root
Stem
Leaf

18. Dicots
Stem
Root
Leaf

19. 21.3 Unique Adaptations Carnivorous Plants
Obtain nitrogen from insects
Modified leaves form traps
Live in areas with poor nutrients
Bogs
Venus flytraps, sundews, pitcher plants
Consumer and producer(photosynthesis)

20. Epiphytes Grows on the surface of another plant without harming it
Nutrition
Photosynthesis
Absorb minerals from rainwater
Reason for adaptation
Living on high branches brings the plant closer to sunlight
Orchids, Spanish “moss”, ferns

21. Parasitic Plants Obtain nutrients from other plants
Taps into vascular tissue
Damages plant
Take away sunlight
Can kill the host by robbing nutrients
Mistletoe, fig