Vegetative Parts of Plants

1. Vegetative Parts of Plants Spring 2012

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; adventitious roots - no nodes/internodes present in roots! • DESCRIPTIVE TERMS: - Taproot (carrot) vs. fibrous roots (grass) - Fibrous, adventitious, aerial, fleshy, prop

9. fibrous storage buttress pneumatophores Fig. 9.2 from Simpson

10. Fibrous roots Tap root

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

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

20. 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.

21. Fig. 9.1 from Simpson

22. Stems: Nodes and Internodes

23. Fig. 9.3 from Simpson

24. Herbaceous stems:

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

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

27. Vines and climbers:

28. Photosynthetic Stems cladodes succulent stems

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

30. Basal rosette:

31. No apparent stems! Subterranean horizontal stems: Rhizomes

32. Rhizomes vs. roots

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

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

35. Woody Stems – Arborescent or shrubby habit

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

37. 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

38. Basic leaf structure

39. Stipules

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

41. pulvinus (lower)

42. Modifications in the Petiolar Region Sheathing leaf bases

43. Venation: Parallel vs. “Netted”

44. Unusual venation: Melastomataceae

45. Leaf blade: Simple Compound Pinnate Palmate

46. Compound leaves Fig. 9.9, Simpson

47. Palmate Leaf – leaflets arise from one point

48. Leaf Arrangement

49. Variation in leaf shape morphology: Sassafras albidum (Lauraceae)

50. Leaf modifications: bracts