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
Most recent evolutionary branch of plants: 120 mya
Unique features:
1. produce specialized reproductive structures called flowers. (many patterns)
2. Seeds form within these flowers as part of modified leaf known as carpel
3. Pollen transfer by insects/ animals: less random than wind in gymnosperms
--Animals visit flowers for food (pollen, nectar) and in so efficiently distribute pollen from 1 flower to another. Flower shape, size & color have all influenced by the evolutionary selective pressures exerted by plant’s need to attract pollinators; co-evolution; species-specific
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
Perfect: both male & female reproductive parts + non-reproductive structures. Imperfect: lack either carpels or stamens
monoecious: both male & female flowers on same sporophyte individuals
dioecious (two house): separate gametes produced on different sporophyte individuals
-makes cross fertilization obligatory and ensures genetic variability in the population but this is done at the cost of lower seed-setting efficiency and also prevents isolated individuals reproducing.
Contrast with spore morphology
heterospory: different spore types give rise to male or female gametophytes, each which produce their respective gametes
homospory: same spore type give rise to bisexual gametophyte that produces both eggs & sperm
Fig Structure of a flower
Flowers may occur singly or in clusters (inflorescence)
Interactive Study Partner Activity 30.2 Angiosperm Life Cycle
seed 
The structure of a flower

7. lily

8. Fig. 42.9

9. Fig

10. Fig

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

12. Fig

13. Pollination place pollen onto stigma of a carpel pollination agents
grasses, many trees: wind
many angiosperms: animals, including insects
self-pollination
brings male & female gametophytes together
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

20. Fig

21. Fig. 42.5

23. Fig. 42.6

24. Fig

25. Fig

26. Fig

27. Fig

28. Fig

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 FLOWER & FRUIT parts (Fig )
Fruit: mature ovary
After fertilization, as seed develops, the ovary wall thickens
e.g., pea pod (fruit) with seeds (mature ovlues, the peas)
apple: The core is the ovary. We eat the ovary wall. Rest of fruit is made from bases of stamens, patels & sepals and the top of the flower stalk.
Animation Fruit Development (dry vs. fleshy fruit)
Relationship between a pea flower and a fruit (pea pod)

31. Fruit or vegetable? botanical: Legal Ripened ovary
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
Animation Fruit Development (dry vs. fleshy fruit)
Fig Development from fruit from Flower (overhead)
pineapple: fruit made of thickened flower parts of all flowers on stalk
strawberry: each seed represents a tiny fruit; fleshy part from flower stalk
Melon: multiple carpels fused; ovary wall
Tomato: ovary wall
citrus: segments are ovaries
corn: each kernel of corn is a fruit.

34. Fig a

35. Fig b

36. Fig c

37. Fig d

38. Fig

39. Fig

40. Fig

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)
Animation Seed Germination
Fig Mobilization of nutrients during germination of cereal, I.e., alpha-amylase (starch to sugar)
--malted barley: germination of seed, and then halted

48. Seed Germination emergence of radicle
detects gravity & grows downward
epicotyl emerges through soil surface
light cues upward & straighter growth
Fig , Seed germination
If no light, bean can still germinate. hypocotyl with hook at tip remains, and internode is long, “reaching” for surface (light). Light color, because not much pigment.
Animation Seedling growth

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

50. Fig

51. Fig a

52. Fig b

55. Fig

56. Fig. 41.7

57. Fig. 41.8

58. Fig. 41.9

59. Fig

60. Fig

61. Fig

62. Fig

64. Fig

65. Fig

66. Fig

67. Fig