2. Plant Anatomy Spikelet Inflorescence Internode Culm (stem) Node (joint) Rhizome Stolon Leaf

3. Plant TISSUES Dermal – epidermis (“skin” of plant) – single layer of tightly packed cells that covers & protects plant Ground – bulk of plant tissue – photosynthetic mesophyll, storage Vascular – transport system in shoots & roots – xylem & phloem

4. Plant CELL types in plant tissues Parenchyma – “typical” plant cells = least specialized – photosynthetic cells, storage cells – tissue of leaves, stem, fruit, storage roots Collenchyma – unevenly thickened primary walls – support Sclerenchyma – very thick, “woody” secondary walls – support – rigid cells that can’t elongate – dead at functional maturity If I ’ d only had triplets!

5. Parenchyma  Parenchyma cells are unspecialized, thin, flexible & carry out many metabolic functions  all other cell types in plants develop from parenchyma

6. Fig. 38.12a

7. Collenchyma  Collenchyma cells have thicker primary walls & provide support  help support without restraining growth  remain alive in maturity the strings in celery stalks are collenchyma

8. Fig. 38.12b

9. Collenchyma Celery

10. Sclerenchyma Thick, rigid cell wall – lignin (wood) – cannot elongate – mostly dead at maturity Cells for support – xylem vessels – xylem tracheids – fibers rope fibers – sclereids nutshells seed coats grittiness in pears

11. Fig. 38.12c

12. Schlerenchyma hau – used to make rope

13. tracheids vessel elements Vascular tissue Aaaah … Structure – Function again! vessel element dead cells  Xylem  move water & minerals up from roots  dead cells at functional maturity  only cell walls remain  need empty pipes to efficiently move H 2 O  transpirational pull

14. Fig. 4.9

15. Fig. 38.13b

16. Fig. 38.13a

17. Fig. 4.6

18. Phloem: food-conducting cells  carry sugars & nutrients throughout plant sieve tube companion cell living cells plasmodesmata sieve plate

19. Phloem: food-conducting cells  sieve tube elements & companion cells

20. Fig. 38.14a

21. Fig. 38.14b

22. Phloem Living cells at functional maturity – cell membrane, cytoplasm control of diffusion – lose their nucleus, ribosomes & vacuole more room for specialized transport of liquid food (sucrose) Cells – sieve tubes sieve plates — end walls — have pores to facilitate flow of fluid between cells – companion cells nucleated cells connected to the sieve-tube help sieve tubes Aaaah … Structure – Function again!

23. Fig. 38.15

24. Cross section of root Vascular bundle (Stele) = contains xylem and phloem Cortex Epidermis Root hairs – Absorb water and minerals

25. Vascular tissue in roots: dicot xylem phloem

26. Cross-section of a root

27. xylem phloem Vascular tissue in roots: monocot

28. Root Cross Section

29. Vascular tissue in stems dicot trees & shrubs monocot grasses & lilies collect annual rings

30. Cross-section: young dicot stem with ring of vascular bundles

31. Fig. 38.25a

32. Fig. 38.25b

33. Monocot stem section showing scattered vascular bundles and enlargement of single vascular bundle (“monkey face”).

34. Woody dicots Discrete vascular bundles replaced by continuous rings of xylem Each ring is xylem produced during one growing season Vascular cambium

35. Fig. 38.7a

36. Fig. 38.7b

37. Cross-section: woody stem showing 3 years of secondary growth. Note pith at center. Dark (reddish) ring is the bark containing a layer of living phloem and outer dead cork.

38. Stems: Secondary growth Vascular tissue, (xylem) makes up the bulk of the stem Form tree rings

39. Lilac leaf cross section

43. Fig. 38.34

48. Fig. 38.8

49. Fig. 38.33