1. Plant Nutrition and transport
Chapter 32

2. Example essay question
Draw a GENERAL diagram that describes how a plant undergoes alternation of generations. In your diagram include all the different phases that the plants go through and the processes that lead from one phase to another. Indicate which phases have the full chromosome number, and which have half the chromosome number.

3. Objectives
Identify the needs of plants and the entry points of materials
Fig 32.1A

4. Uptake and transport of plant nutrients
Co2 enters plants through the leaves
Water, minerals and some O2 enter through from the soil through the roots
All other materials are produced through mixtures of these
Energy is obtained from the respiration of sugars. Leaves produce O2 for this , roots absorb it from the soil

5. Photosynthesis is the process by which autotrophic organisms use light energy to make sugar and oxygen gas from carbon dioxide and water
Carbon dioxide
Water
Glucose
Oxygen gas
PHOTOSYNTHESIS
Respiration: glucose gives up energy as it is oxidized
Loss of hydrogen atoms
Energy
Glucose
Gain of hydrogen atoms
Figure 6.4

6. Solute uptake in the roots
Fig 32.2

7. Solute uptake in the roots
Roots have large surface area
Mycorrhizal fungal interactions supply nutrients and water to the plant
Substances enter roots both intracellularlly and extracellularly, control over substances occurs at the cell membrane
Intracellular (root hair membrane-plasmodesmata-cortex cells, endodermal cells- xylem)
Extracellular (porous cell walls,around casparian strips, to xylem

8. 32.11 Fungi help most plants absorb nutrients from the soil
Relationships with other organisms help plants obtain nutrients
Many plants form mycorrhizae
A network of fungal threads increases a plant's absorption of nutrients and water
The fungus receives some nutrients from the plant
Figure 32.11

9. Properties of water Water molecules stick to one
Another (cohesion) and other stuff
(adhesion)
Water is a polar molecule
Fig 2.9
Fig 2.10

10. Transpiration
Fig 32.3

11. Transpiration Water – cohesion, diffusion, osmosis
How do plants lift water from the roots to the leaves
Root cell membranes pump solutes into the xylem, then water follows
Transpiration – adhesion-cohesion
Evaporation of water from leaves thru stomata
Cohesion of water molecules in the xylem
Adhesion of water to cellulose

12. Transpiration is controlled
by stomata
Fig 32.4

13. Figure 32.UN05
Figure 32.UN05 Testing your knowledge, question 7

14. Sugar transport
Fig 32.5

15. Sugar transport Phloem transports sugars
Sugars are made at “sugar sources”
Sugars travel to and are used at “sugar sinks”
Osmosis is responsible for generating pressure differences that move the sugar.
Proof ! –Aphids!

16. Sugar sink

17. Aphids

18. Nutrients and plant health
Fig 32.6B
Macronutrients
Carbon, Oxygen,Nitrogen,Hydrogen,Sulfur, Phosphorus, Calcium,Potassium,Magnesium Microinutrients
Iron, zinc, etc

19. Soil and plants
Fig 32.8

20. 32.12 Most plants depend on bacteria to supply nitrogen
The Earth’s atmosphere consists of about 80% nitrogen.
However, nitrogen deficiency is the most common nutritional problem in plants. Why is that?
Plants cannot absorb nitrogen directly from the air.
Instead, to be used by plants, nitrogen must be converted to ammonium (NH4+) or nitrate (NO3–).
Student Misconceptions and Concerns
 Students often confuse the terms symbiosis and mutualism, falsely thinking that they mean the same thing. You might wish to clarify these terms to emphasize the more general meaning of symbiosis and the win/win nature of mutualism, a type of symbiosis.
Active Lecture Tips
 With abundant antibacterial products now on the market, students may believe that all bacteria are harmful. Before addressing the mutualistic roles of soil bacteria and plants, challenge your students to work in small groups to explain why planting seeds in sterilized soil could be problematic.

21. 32.12 Most plants depend on bacteria to supply nitrogen
Soil bacteria can convert N2 gas from the air into forms usable by plants via several processes.
Nitrogen-fixing bacteria convert atmospheric N2 to ammonia (NH3) in a process called nitrogen fixation.
Ammonifying bacteria add to the supply of ammonium by decomposing organic matter.
Nitrifying bacteria convert ammonium to nitrates, the form most often taken up by plants.
Student Misconceptions and Concerns
 Students often confuse the terms symbiosis and mutualism, falsely thinking that they mean the same thing. You might wish to clarify these terms to emphasize the more general meaning of symbiosis and the win/win nature of mutualism, a type of symbiosis.
Active Lecture Tips
 With abundant antibacterial products now on the market, students may believe that all bacteria are harmful. Before addressing the mutualistic roles of soil bacteria and plants, challenge your students to work in small groups to explain why planting seeds in sterilized soil could be problematic.

22. N2 ATMOSPHERE ATMOSPHERE SOIL Amino acids, etc. Nitrogen-fixing
Figure
ATMOSPHERE N2
ATMOSPHERE
SOIL
Amino
acids, etc.
Nitrogen-fixing
bacteria
NH4+ H+ N2
NH3
SOIL
NH4+
(ammonium)
NO3−
(nitrate)
Nitrifying
bacteria
Ammonifying
bacteria
Figure The roles of bacteria in supplying nitrogen to plants
Organic
material
Root

23. 32.13 EVOLUTION CONNECTION: Plants have evolved mutually beneficial symbiotic relationships
Some plants form symbioses with nitrogen-fixing bacteria.
Legumes (peas, beans, alfalfa, and others) form root nodules to house nitrogen-fixing symbionts in the genus Rhizobium.
Other plants, such as alders, form symbioses with other kinds of nitrogen-fixing bacteria.
The plant provides the bacteria with carbohydrates and other organic compounds.
Student Misconceptions and Concerns
 Students often confuse the terms symbiosis and mutualism, falsely thinking that they mean the same thing. You might wish to clarify these terms to emphasize the more general meaning of symbiosis and the win/win nature of mutualism, a type of symbiosis.
Teaching Tips
 Mycorrhizae provide an excellent example of a mutualistic relationship. Unless the various types of symbiotic relationships have already been discussed, consider illustrating mutualism and parasitism with the relationships in Modules 32.13–32.14.
 For additional specific details on mycorrhizal relationships, see the literature exchange website for mycorrhiza at

24. Shoot Nucleus Bacteria within vesicle inside cell Nodules Roots
Figure 32.13b-0
Shoot
Nucleus
Bacteria within
vesicle inside cell
Nodules
Roots
Figure 32.13b-0 Root nodules on a pea plant