22 Plant Growth Reproduction and Response.ppt

Plant growth is well explained in the presentation slide

1. 22.1 Plant Life Cycles
KEY CONCEPT
All plants alternate between two phases in their life
cycles.

2. 22.1 Plant Life Cycles
Plant life cycles alternate between producing spores and
gametes.
•A two-phase life cycle is called alternation of generations.
–haploid phase
–diploid phase
–alternates between
the two
fertilization
meiosis
SPOROPHYTE
PHASE
GAMETOPHYTE
PHASE

3. 22.1 Plant Life Cycles
–sporophyte phase is diploid
–begins with fertilized egg
–spores produced through
meiosis
•The gamete-producing plant is the
mature gametophyte.
•The spore-producing plant is the mature sporophyte.
– gametophyte
phase is haploid
– begins with spore
– gametes
produced through
mitosis

4. 22.1 Plant Life Cycles
Life cycle phases look different among various plant
groups.
•Nonvascular plants have a dominant gametophyte phase.
–moss gametophytes look like green carpet
–moss sporophytes shoot up as stalklike structures
sporophyte (2n)
gametophyte (1n)
capsule
spores (1n)

5. 22.1 Plant Life Cycles
sporophyte (2n)
sori
•The sporophyte is the dominant phase for seedless
vascular plants.
–Fern spores form in sacs, sori, on underside of mature
sporophytes (fronds).

6. 22.1 Plant Life Cycles
–A fern gametophyte, or prothallus, produces sperm and
eggs.
gametophyte (1n))
rhizoid
–A zygote forms on the prothallus, growing into the
sporophyte.

7. 22.1 Plant Life Cycles
–pine trees are typical seed plant sporophytes
–female spores produced in female cones
–male spores produced in male cones
–male spores develop into pollen grains, the male
gametophytes
–female spores develop into female gametophytes that
produce eggs
–sperm from pollen travel down pollen tube toward egg
–fertilized egg develops into embryo
–ovule develops into protective pine seed
•The sporophyte is the dominant phase for seed plants.

8. 22.1 Plant Life Cycles
•The sporophyte is the dominant phase for seed plants.

9. 22.1 Plant Life Cycles
Moss life cycle

10. 22.1 Plant Life Cycles
Fern Life Cycle

11. 22.1 Plant Life Cycles
Conifer Life Cycle

12. 22.1 Plant Life Cycles
Flowering Plant Life Cycle

13. •22.2 Reproduction in Flowering Plants
KEY CONCEPT
Reproduction of flowering plants takes place within
flowers.

14. •22.2 Reproduction in Flowering Plants
sepal
Flowers contain reproductive organs protected by
specialized leaves.
•Sepals and petals are modified leaves.
–Sepals are outermost
layer that protects
developing flower

15. •22.2 Reproduction in Flowering Plants
–Petals can help to attract animal pollinators
petal

16. •22.2 Reproduction in Flowering Plants
•A stamen is the male structure of the flower.
–anther produces pollen grains
–filament supports the anther
stamen
filamentanther

17. •22.2 Reproduction in Flowering Plants
carpel style
stigma
ovary
•The innermost layer of a flower is the female carpel.
–stigma is sticky tip
–style is tube leading from stigma to ovary
–ovary produces female gametophyte

18. •22.2 Reproduction in Flowering Plants
Flower Parts

19. •22.2 Reproduction in Flowering Plants
Complete and Perfect Flower
Monocot Flower

20. •22.2 Reproduction in Flowering Plants
Incomplete and Imperfect Flower
Dicot Flower

21. •22.2 Reproduction in Flowering Plants
Incomplete and Imperfect Flower
Dicot Flower

22. •22.2 Reproduction in Flowering Plants
Complete and Perfect Flower
Monocot Flower

23. •22.2 Reproduction in Flowering Plants
Simple fruit

24. •22.2 Reproduction in Flowering Plants
Aggregate fruit

25. •22.2 Reproduction in Flowering Plants
Multiple fruit

26. •22.2 Reproduction in Flowering Plants
Flowering plants can be pollinated by wind or animals.
•Flowering plants pollinated when pollen grains land on
stigma.
•Wind pollinated flowers have small flowers and large
amounts of pollen.

27. •22.2 Reproduction in Flowering Plants
•Animal pollinated flowers have larger flowers and less
pollen.
pollen grains
–many flowering plants pollinated by animal pollinators
–pollination occurs as animal feeds from flower to flower
–animal pollination more efficient than wind pollination

28. •22.2 Reproduction in Flowering Plants
Fertilization takes place within the flower.
•Male gametophytes, or pollen grains, are produced in the
anthers.
–male spores produced in
anthers by meiosis
–each spore divides by
mitosis to form two
haploid cells
–two cells form a
single pollen grain
pollen grain

29. •22.2 Reproduction in Flowering Plants
–four female spores produced in ovule by meiosis
–one spore develops into female gametophyte
–female gametophyte contains seven cells
–one cell has two nuclei, or polar nuclei
–one cell will develop into an egg
•One female gametophyte can form in each ovule of a
flower’s ovary.

30. •22.2 Reproduction in Flowering Plants
•Pollination occurs when a pollen grain lands on a stigma.
pollen tube
sperm
stigma
–one cell from pollen grain forms pollen tube
–other cell forms two sperm that travel down tube

31. •22.2 Reproduction in Flowering Plants
•Flowering plants go through the process of double
fertilization.
female
gametophyte
ovule
egg
sperm
polar nuclei

32. •22.2 Reproduction in Flowering Plants
endosperm
seed coat
embryo
–one sperm fertilizes
the egg
–other sperm unites
with polar nuclei,
forming endosperm
–endosperm provides
food supply for
embryo
•Flowering plants go through the process of double
fertilization.

33. •22.2 Reproduction in Flowering Plants
•Each ovule becomes a seed.
•The surrounding ovary grows into a fruit.

34. •22.3 Seed Dispersal and Germination
KEY CONCEPT
Seeds disperse and begin to grow when conditions
are favorable.

35. •22.3 Seed Dispersal and Germination
Animals, wind, and water can spread seeds.
•Seeds dispersed by animals can have nutritious fruits or
fruits that cling.

36. •22.3 Seed Dispersal and Germination
•Seeds dispersed by wind can have wing- or parachute-
like fruits.
Cypselae
Double samaras

37. •22.3 Seed Dispersal and Germination
•Seeds dispersed by water can have fruits that float.

38. •22.3 Seed Dispersal and Germination

39. •22.3 Seed Dispersal and Germination
Seeds begin to grow when environmental conditions are
favorable.
•Seed dormancy is a state in which the embryo has stopped
growing.
–Dormancy may end
when conditions are
favorable.
–While dormant,
embryo can withstand
extreme conditions.

40. •22.3 Seed Dispersal and Germination
•Germination begins the growth of an embryo into a seedling.
–water causes seed to swell and crack coat
–embryonic root, radicle, is first to emerge
–water activates enzymes that help send sugars to
embryo

41. •22.3 Seed Dispersal and Germination
•Germination begins the growth of an embryo into a seedling.
–water causes seed to swell and crack coat
–embryonic root, radicle, is first to emerge
–water activates enzymes that help send sugars to embryo
–embryonic shoot, plumule, emerges next

42. •22.3 Seed Dispersal and Germination
•Germination begins the growth of an embryo into a
seedling.
–water causes seed to swell and crack coat
–embryonic root, radicle, is first to emerge
–water activates enzymes that help send sugars to
embryo
–embryonic shoot, plumule, emerges next
–leaves emerge last

43. •22.3 Seed Dispersal and Germination
•Once photosynthesis begins, the plant is called a seedling.

44. •22.4 Asexual Reproduction
KEY CONCEPT
Plants can produce genetic clones of themselves
through asexual reproduction.

45. •22.4 Asexual Reproduction
Plants can reproduce asexually with stems, leaves, or
roots.
•Asexual reproduction allows a plant to make copies of itself.
•Regeneration is one type of asexual reproduction.
–plants grow a new individual from fragment of parent
–occurs when piece of a stem, leaf, or root falls off parent
plant

46. •22.4 Asexual Reproduction
–stems, leaves, or roots
attached to parent plant
produce new individuals
–specific adaptations
include stolons, rhizomes,
and tubers
•Vegetative reproduction is another type of asexual
reproduction.

47. •22.4 Asexual Reproduction
Humans can produce plants with desirable traits using
vegetative structures.
•Vegetative propagation takes advantage of plants’ ability to
reproduce asexually.
•Humans use one plant with desirable traits to produce
many individuals.
– grafting joins the parts of
two plants together to form
a hybrid plant
–cutting of leaves or stems may grow new roots

48. •22.5 Plant Hormones and Responses
KEY CONCEPT
Plant hormones guide plant growth and development.

49. •22.5 Plant Hormones and Responses
Plant hormones regulate plant functions.
•Hormones are chemical messengers.
–produced in one part of an organism
–stimulates or suppresses activity in another part

50. •22.5 Plant Hormones and Responses
–ending seed dormancy
–rapid growth of young
seedlings
–rapid growth of some
flower stalks
•Gibberellins are plant hormones that produce dramatic
increases in size.

51. •22.5 Plant Hormones and Responses
–some fruits picked before
they are ripe
–sprayed with ethylene to
ripen when reach
destination
•Ethylene causes the ripening of fruits.

52. •22.5 Plant Hormones and Responses
–final stage in cell division
–produced in growing roots, seeds, and fruits
–involved in growth of side branches
•Cytokinins stimulate cytokinesis.

53. •22.5 Plant Hormones and Responses
•Auxins lengthen plant cells in the growing tip.
–stimulates growth of
primary stem
–controls some forms of
tropism
• A tropism is the movement
of plant in response to an

environmental stimulus.

54. •22.5 Plant Hormones and Responses
Plants can respond to light, touch, gravity, and seasonal
changes.
•Phototropism is the
tendency of a plant to
grow toward light.
–auxins build up on
shaded side of stem
–cells on shaded
side lengthen
–causes stem to
bend toward light

55. •22.5 Plant Hormones and Responses
–climbing plants and vines
–plants that grow in direction of constant wind
•Thigmotropism is a plant’s response to touchlike stimuli.

56. •22.5 Plant Hormones and Responses
–positive gravitropism is downward growth (roots)
–negative gravitropism is upward growth (shoots)
•Gravitropism is a plant’s response to Earth’s gravitational
pull.

57. •22.5 Plant Hormones and Responses
–Some responses protect
plants from predators.
–Some responses allow
plants to capture food.
•Some plants have rapid responses not involving growth.

58. •22.5 Plant Hormones and Responses
–triggers some plants to flower
–triggers fall colors/winter dormancy of deciduous trees
•Photoperiodism is a response to the changing lengths of
day and night.