1. 1. Plant cell walls (Ch. 15) 2. Dendrochronology

3. Glucan chains may have 1000s to 10,000s of glucose residues

6. Some of the many compounds found in heartwood (of giant sequoia). Many are not cell wall compounds. Lamlom & Savidge 2006.

7. Cellulose microfibrils are synthesized at plasmamembrane by “particle rosettes” that include cellulose synthase.

8. Cell wall matrix polysaccharides synthesized in Golgi app and secreted to wall via membrane vesicle. Matrix polysaccharides Hemicelluloses xyloglucan glucuronoarabinoxylans glucomannans

9. Pectins are gel-forming polysaccharide components of cell wall matrix

10. Secondary walls contain lignin that displaces water, binds cellulose, and prevents cell expansion.

11. Orientation of cellulose microfibrils determines direction of cell expansion.

12. Rate of cell expansion determined by cell wall extensibility and turgor pressure

13. Tree rings and dendrochronology

14. Diffuse porous Ring porous

15. Tree rings for reconstructing past climate CO 2 fertilization insect outbreaks fire history forest stand demography

23. Tree rings record insect outbreaks. Pandora moth on ponderosa pine.

27. Tree rings and forest demographics