Pros and Cons of Clonal Growth

Transcription

1 Clonal Growth

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

3 Forms of Clonal Growth Phalanx Guerilla

4 Modes of Foraging Behavior Number of Branches (n) Ramet size (S) Shoot Root q Branch angle (q)

5 Optimal Foraging? Nutrient Rich Nutrient Poor Nutrient Rich

6 Optimal Foraging: Rich Habitat X

7 Optimal Foraging: Poor Habitat X

8 Optimal Foraging through a Plastic Response

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

10 An Experimental Test of Optimal Foraging

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

12 General Growth Pattern

13 Experimental Design Nutrient poor Legend Nutrient rich Mixed

14 Predictions and Results 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

15 Predictions and Results Mixed Treatment Nutrient Rich Areas Short internodes Profuse branching Many large ramets High shoot:root Nutrient Poor Areas Long internodes Few branches Few small ramets Low shoot:root

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

17 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?

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

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

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

21 Experimental Examination of Integration through Phloem Leaf labeled with 14 C

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

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

24 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

25 Forms of Asexual Reproduction in Plants

26 Clonal Growth (revisited) Rhizome Stolon Bulbils Suckers Plantlets

27 Fragmentation: jumping cholla

28 Production of seeds with no fertilization Agamospermy

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

30 Sexual Reproduction in Plants

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

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

33 Gender Expression in Plants Hermaphrodites

34 Gender Expression in Plants Hermaphrodites

35 Gender Expression in Plants Hermaphrodites

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

37 Distribution of Flower Types

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

39 Semelparity: A closer look Annuals Biennials