1. Essential Nutrients Soils Nodules and Mycorrhizae Plant Nutrition - Ch 37

2. Notes This is a short chapter - read it thoroughly. Pay attention (in all the chapters) to the “Concept Check” questions.

3. Essential Nutrients - what do plants need?

4. One approach to “What are plants made of?” Mostly water (except woody parts) Otherwise, mostly carbohydrate, including cellulose But also phospolipids, nucleic acids, proteins, chlorophyll, other enzymes, coenzymes and cofactors

5. What is essential? Drying and burning plants only takes you so far. Plants incorporate minerals selectively, but the “filter” is imperfect. –This can be useful: “attack of the metal-eating plants” How then to determine what’s essential?

6. Hydroponics

7. Essential Nutrient = plant cannot go from seed to seed without it.

8. Macronutrients Carbon Oxygen Hydrogen Nitrogen Sulfur Phosphorus Potassium Calcium Magnesium

9. ..and Micronutrients Chlorine Iron Boron Manganese Zinc Copper Molybdenum Nickel Often act as or with catalysts Cofactors - metal ions that enable enzymes Needed in very small quantities –Example - Mo

10. Soil Origins Soil Horizons Soil Composition –Sediment texture- clays vs. sands. Loam. –humus SOILS

11. Cation Exchange

12. Nitrogen Fixation and Root Nodules Nitrogen is a limiting nutrient for much plant growth Atmospheric Nitrogen (N 2 ) is unavailable to plants Plants rely on bacteria to fix Nitrogen into ammonia (NH 4 ) and nitrate (NO 3 - ) Some of these bacteria form symbiotic relationships, living in nodules in plant roots (especially in legumes - peas, beans etc)

13. Nitrogen Cycle

14. N-fixing nodules on legume root

15. Mycorrhizae Symbiosis between plant roots and fungal myceliae Increases plant absorption of minerals greatly The fungus gets sugar, other nutrients Occurs in 90% of plant species Fungal species are specific to plant species

17. Weirdos