January 7 ~Feb1 2013
Midterm date: Monday Febuary 4 2013. 5-7pm
Module 2: Begins on Tuesday Feb 5 . th
Total: 12 lectures
1-2: Tree of life-plants
3-4 Plant cells and plant tissues
5-6. From seed to tree
7-8. Freom tree to seed
9. Transport in plants
10. Plant nutrition and soils
11. Plant defense
12. Plant life on the edge.
Lecture 4 notes (Plant cells and plant tissues)
B) Differentiated cells
ii) Complex plant tissues.
a) epidermis-protection, gas exchange, uptake. In roots, shoots, leaves.
Comparative form and function=variation on a theme
One. Epidermal hairs (e.g Lateral root, root hair, root cap, root epidermis)
Two. Epidermal glands (e.g hemp. Cannibis sativa)
Three. Epidermal stinging hairs (e.g stinging nettle. Urtica dioica.)
Four. Sonical epidermis. (e.g violet, viola, velvety sheen)
Five. Epidermal platelets (e.g silverberry. Elaeagnus)
Six. Water-repellent epidermis (e.g Lotus. Nelumbo nucifera)
Seven. Epidermal sensing hair (e.g venus flytrap. Dionaea muscipula)
Eight. Epidermis of the pitcher plant. Nepenthes sp. – have 3 different types b) periderm-protection, gas exchange
Perennial (living for several years)plants-wear and tear of epidermis. Growth of
stem=ripping epidermis apart. So need sealing.
Cork cambium-source of new periderm. Secondary meristem.
Cork cells-protection. Dead at maturity, wall of lignin (anti-microbial), suberin(wax-
like to go against desiccation)
c) xylem-transport, support, storage
First. Tracheids-transport, support. Dead at maturity
Second. Vessels-transport, support. Dead at maturity
Third. Parenchyma-support. Alive
Fourth. Fibers-support. Alive
Continuous system transporting water and minerals form roots ot rest of plants.
Trachieds: water moves only between pits.
Tick lignified cell walls
Water flows through adjacent pits from cell to cell
Soft wood conifers
Vessels: water moves between perforations and pits.
Thick lignified cell walls
Water flows through openings-perforations, and pits from cell to cell.
Annular vessel, spiral vessel, scalariform vessel, pitted vessel.
Surrounded by parenchyma.
Trachields developed first then vessels.
All tracheids, vessels, parenchyma, fibers are lignified=hard,sturdy,wood.
d) phloem-transport. 2 types: sieve tube memebers and companion cell