1. Experimental Evidence for Tradeoffs

2. Survival vs. Fecundity (Astrocaryum mexicanum) Photo copyright © 1998, Jody Haynes

3. Size vs. Fecundity (Poa pratensis)

4. Fecundity vs. Fecundity (Poa pratensis)

5. Tradeoffs “If two processes require the use of a limiting resource, then allocation of the resource to one process requires de-allocation to the second.”

6. The Bottom Line Ideal Plant

7. Key Stages in the Life-History of a Plant Growth Flowering Pollination Seed Maturation Dispersal Dormancy Germination seed phase

8. Growth in Plants

9. Growth Apical meristems Source of plant elongation; often acting to suppress lateral growth from other nodes

10. Growth Apical meristems Axillary meristems at nodes Gives rise to leaves and flowers; can also form lateral branches when not suppressed by apical meristem

11. Growth Apical meristems Axillary meristems at nodes Growth between adjacent nodes Internodes

12. Growth Apical meristems Axillary meristems at nodes Cambium in many perennial plants (not monocots) allows them to increase in girth over time Secondary growth Internodes

13. Ecology and Plant Architecture The Raunkier system of classification snowpack

14. Plant growth is generally a Modular Process

15. Clonal Growth

16. Pros and Cons of Clonal Growth AdvantagesDisadvantages Rapid growth More widespread foraging Lower mortality than seedlings Greater competitive ability Avoid cost of sexual repro. Resource sharing No recombination Limited dispersal range Disease accumulation

17. Forms of Clonal Growth PhalanxGuerilla

18. Phalanx Growth: Aspen Example

19. Guerilla Growth: Solidago Example

20. Modes of Foraging Behavior Ramet size (S) Shoot Root  Branch angle (  ) Number of Branches (n)

21. Optimal Foraging? Nutrient Rich Nutrient Poor Nutrient Rich

22. Optimal Foraging: Rich Habitat X

23. Optimal Foraging: Poor Habitat X

24. Optimal Foraging through a Plastic Response

25. Predictions Nutrient Rich HabitatNutrient Poor Habitat Short internodes Profuse branching Acute branch angles High shoot:root Long internodes Few branches Obtuse branch angles Low shoot:root

26. An Experimental Test of Optimal Foraging

27. The plant: Glechoma hederacea Slade, A. J., and M. J. Hutchings. 1987. The effects of nutrient availability on foraging in the clonal herb Glechoma hederacea. Journal of Ecology 75:95-112.

28. General Growth Pattern

29. Experimental Design Legend Nutrient poor Nutrient rich Mixed

30. Predictions Nutrient Rich Habitat Nutrient Poor Habitat Short internodes Profuse branching Many large ramets High shoot:root Long internodes Few branches Few small ramets Low shoot:root and Results

31. Predictions and Results Nutrient Rich AreasNutrient Poor Areas Short internodes Profuse branching Many large ramets High shoot:root Long internodes Few branches Few small ramets Low shoot:root Mixed Treatment Intermediate growth in all locations

32. General Interpretation Glecoma hederacea exhibits a plastic growth response to nutrient conditions This response is not localized, but represents an average to conditions encountered across the clone What role does physiological integration play?

33. Physiological Integration through Movement of Resources Xylem: Transport of raw materials, e.g., H20 and soil nutrients Phloem: Transport of products of photosynthesis

34. Experimental Examination of Integration through Xylem Price, E. A. C., C. Marshall, and M. Hutchings. 1992. Studies of growth in the clonal herb Glechoma hederacea. I. Patterns of physiological integration. Journal of Ecology 80:35-38. Experimental design Cut leaf off Inject fuchsin dye into xylem

35. Leaf with dye Leaf without dye Experimental Examination of Integration through Xylem Experimental results Complex pattern of nutrient flow, depends on xylem architecture Apparent unidirectional flow of nutrients

36. Experimental Examination of Integration through Phloem Leaf labeled with 14 C

37. Experimental Examination of Integration through Phloem Leaf labeled with 14 C Resulting radiograph

38. Experimental Examination of Integration through Phloem Interpretation Photosynthate stays in leaf or is transported to young developing tissues Source-sink relationship

39. General Interpretation of Experiments Patterns of physiological integration can be shown Resource sharing seems to be in the direction of younger ramets Optimal foraging is an ideal that is only partially met

40. Forms of Asexual Reproduction in Plants

41. Clonal Growth (revisited) Rhizome Stolon Suckers Plantlets Bulbils

42. Fragmentation: jumping cholla

43. Agamospermy Production of seeds with no fertilization

44. Key Stages in the Life-History of a Plant Growth Flowering Pollination Seed Maturation Dispersal Dormancy Germination seed phase

45. Sexual Reproduction in Plants

46. Typical Angiosperm Lifecycle Alternation of generations Sporophyte (2n) Gametophytes (1n)

47. Typical Angiosperm Lifecycle Alternation of generations Sporophyte (2n) Gametophytes (1n) Fertilization

48. ♂ ♀ Hermaphrodites Gender Expression in Plants

49. Sequential Hermaphrodism Jack-in-the-pulpet (Arisemea triphyllum) Some plants change sex over time!

50. Distribution of Flower Types

51. Variability in Flowering Patterns Semelparity Iteroparity Flower once and die Flower many times

52. Semelparity: A closer look Annuals Biennials

53. Biennial plant Year 1 Year 2 © R. Jackson

54. Semelparity: A closer look Big bang perennials

55. Bet Hedging Big bang Vegetative reproduction

56. Semelparity vs. Iteroparity

57. Tradeoffs in Phenology of Flowering AnnualsPerennialsBig Bang Advantages Quick reproduction Protected as seed Disadvantages High environmental risk Poor competitors Special Circumstances Poor conditions for extended time periods Strong signal for breaking seed dormancy Advantages Increased size Reproduce when resources are plentiful Disadvantages Slower initial population growth Require relatively stable habitats Special Circumstances Advantages Increased fecundity* Predator satiation Disadvantages Delayed reproduction “All eggs in one basket” Special Circumstances Can succeed in situations with high stress, low resources Better competitor* * (vs. annuals) Unpredictable resource for seed predators

58. A Majority of Plants are Iteroparous Perennials