Ch. 5 & 6- Flowers & Fruits

1. Ch. 5 & 6- Flowers & Fruits

2. Angiosperms (flowering plants) • Unique among plants because they have sexual reproductive structures contained in a flower • derived from modified leaves • seeds form inside fleshy fruit • pollinated by insects or other animals Fruit as an adaptation for seed dispersal: Red berries and dandelion

6. Flower arrangements • Perfect: both stamens & carpels • Imperfect: missing either stamens or carpels • Monoecious: both male & female flowers on same plant • Dioecious: male & female flowers on separate plants female male Embryo sac  fruit seed  The structure of a flower

7. lily

8. Fig. 42.9

9. Fig. 42.10

10. Fig. 42.17

11. monoecious species, male (left) and female (right) begonia flowers

12. Fig. 42.16

13. Pollination • place pollen onto stigma of a carpel • pollination agents • grasses, many trees: wind • many angiosperms: animals, including insects • self-pollination A relationship between an angiosperm and its pollinator: Hummingbird and flower (left); bee and Scotch broom (right)

14. How do flowers attract the pollinator of choice? • Insect: bright, showy petals with fragrant aromas, rich in nectar • E.g.: moths=white, night; flies=“smelly” • Hummingbird: bright, often red, no aroma • Wind: small and inconspicuous with copious production of dry, lightweight pollen

18. Fig. 42.1

19. Fig. 42.11

20. Fig. 42.13

21. Fig. 42.5

23. Fig. 42.6

24. Fig. 42.12

25. Fig. 42.14

26. Fig. 42.15

27. Fig. 42.19

28. Fig. 42.20

29. Fruits • What is a fruit? • What are the purpose of fruit? • How is a fruit formed?

30. Fruit = “mature ovary”purpose: protects seeds, dispersal aid Relationship between a pea flower and a fruit (pea pod)

31. Fruit or vegetable? • botanical: • Ripened ovary • Legal • Something that tastes sweet and is eaten as dessert

32. Types of Fruits • Dry fruits: Tough or papery pericarp • Fleshy fruits: Soft and juicy pericarp • Drupe • Berry • Aggregate • Multiple • Accessory

33. Development of fruit from flower • drupe • berry • simple = 1 ovary of 1 flower • e.g., cherry, soybean pod • compound = multiple ovaries • aggregate = of one flower • e.g., raspberry, blackberry • multiple = of many flowers (inflorescence) • e.g., pineapple • accessory = parts other than ovary • e.g., strawberry, apple, melon, tomato

34. Fig. 40.11a

35. Fig. 40.11b

36. Fig. 40.11c

37. Fig. 40.11d

38. Fig. 40.12

39. Fig. 40.13

40. Fig. 40.14

42. Seeds • Contain embryonic plant plus nutritive tissue & tough outer coat • Starting point for next generation

43. Fig. 40.2a

44. Fig. 40.2b

45. Cotyledons (embryonic leaves) • Single cotyledon = monocot • Two large cotyledons = dicot • Cotyledons can be “fleshy” or “leafy” • Cotyledons can be kept belowground or elevated above ground

46. Fig. 40.7

47. Seed Germination • imbibition: absorption of water • mobilization of food reserves • enzyme activity digests endosperm (converts starch to sugar)

48. Seed Germination • emergence of radicle • detects gravity & grows downward • epicotyl emerges through soil surface • light cues upward & straighter growth

49. Fig. 40.1 With light: Green Shorter Open cotyledons Straight stem Without light: Yellow Elongated Closed cotyledons Hooked stem

50. Fig. 40.10