1. Chapter 37
Plant Nutrition & Soil

2. Macronutrients & Micronutrients
Essential nutrients – Nutrients that must be consumed, plants cannot make these nutrients
Macronutrients – Needed in large amounts
Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorous, Sulfur, Potassium, Calcium, & Magnesium
Micronutrients – Needed only in small amounts
Iron, Manganese, Zinc, & Copper

5. Rhizo - Rhizosphere – soil layer bound to the plant’s roots
Rhizobacteria – soil bacteria
Some rhizobacteria are called plant-growth-promoting rhizobacteria (PGPR)
Wanna guess what they do?
They promote plant growth by:
Producing chemicals that stimulate growth
Produce antibiotics to protect roots from infection
Absorb toxic metals or make nutrients available for plants

6. Rhizobacteria (Page 2) Plant benefits were discussed on prior slide
Bacterial benefits since 20% of photosynthetic products go to the bacteria
Hence, bacteria benefit from a healthy plant (roots) in the rhizosphere

7. Rhizobium Bacteria
Bacteria that fix atmospheric nitrogen + supply it as ammonium
Legumes have a ready source of nitrogen
Symbioses with Rhizobium (Root living) bacteria
Peas, soybeans, peanuts, and alfalfa
Nodules – swellings in the roots infected by rhizobium bacteria
Bacteroids – bacteria in vesicles in root cells in the nodules

9. Mutualistic Relationship?
Rhizobium bacteria provide nitrogen in a usable form
Used to make amino acids for plant growth
Plant provides photosynthetic products to the nodules via the vascular system

11. Mycorrhizae Mutualistic relationship between plant roots and fungus
Two types
Ectomycorrhizae
Mycelium forms a dense sheath over the root surface
Hyphae extend from the root to the soil = increase surface area for absorption of water & minerals
Hyphae do NOT penetrate root cells

12. Mycorrhizae (Page 2) Endomycorrizae
Also called arbuscular mycorrhizae (That’s a mouthful!)
Most common type (85% of associations)
Look like regular roots
No dense mantle covering root surface
Hyphae penetrate the cortex (Which tissue type?)

14. Chapter 38
Angiosperm Reproduction

15. Angiosperm Reproduction
Angiosperms have 3 unique features:
Flowers, Fruits, & Double Fertilization
Microsporangia
Pollen sacs in the anther
Diploid cells = meiosis  male gametophyte (pollen)
Pollen has 2 haploid nuclei
Tube nucleus – 1 sperm develops into a pollen tube
Generative nucleus – divides into 2 sperm cells which remain inside the pollen tube

17. Ovary Ovules form with a diploid cell Soon 4 haploid megapsores form
Eventually get 8 haploid nuclei, but only 3 are most important
1 haploid nucleus = egg
Will combine with sperm nucleus to form the zygote
2 other nuclei are called polar nuclei
Polar nuclei will fuse with sperm nucleus to make 3n endosperm

20. Pollination Pollen lands on stigma Pollen tube made from pollen grain
Pollen tube grows down into the ovary
When pollen tube reaches ovule, double fertilization occurs

21. Double Fertilization
Double fertilization is the union of 2 sperm cells forming zygote & endosperm
Unique to angiosperms
1 sperm fertilizes the egg  zygote
Zygote develops into the embryo  sporophyte
Other sperm combines with both polar nuclei = 3n nucleus
This 3n tissue  endosperm
Endosperm – food storing tissue in the seed

22. After double fertilization
Ovule develops into a seed
Ovary develops into fruit which encloses the seed
Fruit protects the enclosed seed
Fruit aids in dispersal by wind or animales
Seed coat – protects embryo & its food supply
Radicle – embryonic root
Epicotyl – shoot tip with pair of miniature leaves

24. Seed As the seed matures, It goes dormant
Low metabolic rate, growth and development are suspended
Seed resumes growth given suitable environmental conditions for germination