Vegetative Parts of Plants

1. Vegetative Parts of Plants Spring 2013

2. Descriptive Terminology • LEARN DESCRIPTIVE TERMINOLOGY = PHYTOGRAPHY - Vegetative - Floral/inflorescence - Fruit • ASSOCIATE STRUCTURES WITH TERMS - Significant range of variation - Learn to identify major structures and modifications

3. R. W. Pohl Conservatory5th floor – Bessey Hall • AVAILABLE TO BIOLOGY 366 STUDENTS - Free to look at plants to get a better idea of morphological structures and taxonomic diversity. • OPEN HOURS ARE 9:00 a.m. to 5:00 p.m. Monday - Friday - Some Friday afternoons conservatory is closed for pesticide applications. Some research areas are not available for general viewing. - Access by the elevator. Pay attention to warning signs! • PLANTS AND PLANT PARTS ARE NOT TO BE REMOVED - Pesticides have been applied to all plant material. - Do not eat any plant products. - Do not disturb any research areas.

4. Sequoiadendron— most massive Sequoia—tallest

5. Among the smallest plants in the world: Duckweeds (Lemna, Araceae) Root and 1-2 leaves; floating aquatic

6. Vegetative Parts of Plants NON-REPRODUCTIVE ORGANS: ROOTS - STEMS - LEAVES

7. Fig. 9.1 from Simpson

8. Roots • FUNCTIONS - Anchoring and support - Absorption of water and mineral nutrients; mycorrhizae • STRUCTURE - xylem and phloem usually in a central vascular strand - no cuticle (except on aerial roots), root hairs. - branching pattern variable - no nodes/internodes present in roots! • DESCRIPTIVE TERMS: - Taproot (carrot) vs. fibrous roots (grass) - Fibrous, adventitious, aerial, fleshy, prop - Adventitious roots (from stems)

9. Fibrous roots Tap root

10. Adventitious roots – roots produced by structures other than another root(e.g.,stems)

11. Root modifications storage buttress pneumatophores Fig. 9.2 from Simpson

12. Root Modifications: Ficus (Moraceae) “Strangler Fig” Adaptation for anchoring and nutrient gathering – begins as an epiphyte, and sends down adventitious roots.

13. Prop roots (adventitious) Pandanus (Pandanaceae)

14. Haustorial roots Found in parasitic plants. Host stem Dodder (Cuscuta, Convolvulaceae)

15. Buttress roots

16. Modifications of Roots: Mangroves – Anchoring, support, and aeration (coastline habitats)

17. Mangrove: Pre-dehiscence germination Root is already emerged from seed before it is separated from the tree.

18. Root Modifications: Aerenchyma in aquatics

19. Roots and other organisms Mycorrhizal associations were critical to the invasion of land by plants and are nearly universal in plants. endomycorrhizae ectomycorrhizae

20. Some angiosperm families (primarily the legumes, Fabaceae) have root nodules housing nitrogren-fixing bacteria

21. Stems • FUNCTIONS - support and exposure of leaves to light, flowers to pollination agents, fruits to dispersal agents - vascular conduction of water/minerals and photosynthates - sometimes the primary photosynthetic organ • STRUCTURE - nodes and internodes; rearrangement of vascular tissues - ring of bundles or scattered bundles in primary stems - secondary growth produces secondary xylem (wood) - epidermis in primary stems; bark in woody plants - buds: terminal, axillary/lateral, bud scale scars • DESCRIPTIVE TERMS: - Branching patterns; bulbs, herbaceous, woody - Horizontal stems: above ground = stolons; below = rhizomes - Vines, shrubs, trees, succulent, tendril, cladode, etc.

22. Fig. 9.1 from Simpson

23. Stems: Nodes and Internodes

24. Fig. 9.3 from Simpson

25. Herbaceous stems:

26. Stems: Some can be hollow;loss of pith during maturation

27. Modifications in the Petiolar Region Swollen nodes: Characteristic of the Pink Family (Caryophyllaceae)

28. Vines and climbers:

29. Photosynthetic Stems cladodes succulent stems

30. Tussock: In plants with a graminoid (grass- like) habit, stems may not be evident. This example is a ‘tussock’ habit, forming clumps.

31. Basal rosette:

32. No apparent stems! Subterranean horizontal stems: Rhizomes

33. Rhizomes vs. roots

34. Tubers (underground storage stems): wsu.edu energyfarms.com

35. Bulbs: stems (internodes) are shortened and leaves are fleshy and protective.

36. Woody Stems – Arborescent or shrubby habit

37. Stem Modifications: Bark (phellem or cork + 2° phloem) Most woody plants produce bark, a growth of the cork cambial layer, for mechanical protection and to reduce water loss.

38. Bark variation lenticels

39. Leaves • FUNCTIONS - light capture, production of photosynthates, transpiration • STRUCTURE - petiole, stipules, pulvinus, blade (lamina), veins - vestiture (minimally a cuticle), hairs, scales, etc. - simple vs. compound (blade divided into discrete parts) - many modifications, including extreme reduction - virtually always with a bud or branch in the axil • DESCRIPTIVE TERMS: - Many, based on leaf shape, size, color, venation, margin, apex, base, arrangement, number, presentation

40. Basic leaf structure

41. Stipules

42. Modifications in the Petiolar Region Ocrea: stipular tube (characteristic of most of the Buckwheat Family, Polygonaceae)

43. pulvinus (lower) axillary bud

44. Modifications in the Petiolar Region Sheathing leaf bases

45. Venation: Parallel vs. “Netted”

46. Unusual venation: Melastomataceae

47. Leaf blade: Simple Compound Pinnate Palmate

48. Compound leaves Fig. 9.9, Simpson

49. Palmate Leaf – leaflets arise from one point

50. Twice-pinnately compound