1. BIOLOGY

2. Meristems
Unlike animals, plants have permanent regions of cell division
Meristems

3. Meristems Apical Meristems Cell division at tips of roots and stems
Produce primary tissue

4. Meristems Lateral Meristems
Cell division that increases girth of roots and stems
Secondary growth

5. Lateral Meristems
Vascular cambium
Conduction
“Plumbing”

6. Complex Tissue Xylem Conducts water and minerals from the roots
Transports upward

7. Complex Tissue
Xylem
Openings along cell walls connect side by side cells
Lateral flow in trees
Rays

8. Complex Tissue Phloem Conduct water and food in both directions
Primarily down

9. Lateral Meristems Cork cambium
Layer of cells outside phloem layer of vascular cambium
Inside the outer bark

10. Dicots Dicotyledonous Two leaves emerge from seed Dicot Cotyledons
Not true leaves

11. Dicots Herbaceous dicots Soft tissue Primary xylem/phloem only
Annual dicots
Germinate and die in one season
Perennial dicots
Regrow new tissue from roots

12. Dicots Woody dicots Hard tissue Secondary xylem and phloem
Perennial woody dicots only
Live multiple seasons

13. Secondary xylem Secondary xylem cells produced inside cambium
Toward center of stem
Transports water and nutrients up the plant

14. Secondary xylem Secondary xylem eventually becomes wood
As cells become inactive, they become structural

15. SPRING WOOD Active growth produces large xylem cells
Lighter colored band

16. Summer wood
Smaller and fewer XYLEM cells
Darker band

17. GROWTH RINGS The alternation of spring and summer growth bands
Fire, drought, and other events
Increment borer to read rings

18. Heartwood versus sapwood
Inactive xylem cells
Accumulation of resins, gums, and tannins
Darker color of wood
Sapwood
active xylem (near cambium)
Lighter color wood

19. Heartwood versus sapwood
Heartwood can rot but tree can still function
Portion of heartwood and sapwood can be removed

20. Girdling phloem Phloem nearest cambium transport the most sugars
Cambium stripped from grapevines to trap sugars

21. Cork Cambium Outer bark of woody plants Developed from epidermis
Cork cells
Also called phellogen
Impregnated with suberin
Waxy substance

22. Monocots Vascular bundles throughout stem Xylem facing center
Phloem facing out

23. Monocots
No tree rings
Palm trees
Do not seal wounds

24. Xylem, Phloem, and Transpiration