Plant%20Life%20Cycles%20CHAPTER%2030

1
Plant Life CyclesCHAPTER 30
2
Flowering Plant Reproduction
3
Angiosperms (flowering plants)

• Plants that protect their seeds within the body
  of a fruit.
• Make up ¾s of all plants, including
• Trees, shrubs, herbs,
• grasses, water plants

4
Male Reproductive Structure

• The stamen consists of two parts Anther and
  Filament
• The anther is where meiosis occurs to produce
  haploid pollen
• The filament is a stalk that supports the anther

5
Female Reproductive Structure

• The pistil consists of the stigma, style and
  ovary
• The sticky stigma receives the pollen from the
  anther
• The pollen grows a tube down through the style
• Meiosis occurs in the ovary to produce haploid
  ovules

6
Reproductive Structures

• Petals colourful
• structures that attract pollinators.

• Sepals surround and protect the flower bud.

7
Pollination

• Wind, insects or other animals transfer pollen
  from the anther of one flower to the stigma of
  another
• Flowers vary depending on pollination mechanism

8
Pollination Vectors
Wind Pollination Dull, scentless flowers with
reduced petals
Bees/Butterfly Pollination Bright color,
nectaries, scent. They sip nectar, get pollen
on coats, transfer pollen from flower to flower
Bird Pollination Nectaries, bright colors,
tube-like flowers
Moth Pollination White petals, open at night
Fly PollinationRank odor, flesh colored petals
9
How Do Flowers Make Seeds and Fruits?

• Ovary the bottom part of the pistil in which
  seeds form
• Ovule - the inner part of an ovary that contains
  an egg
• embryo tiny part of a seed that can grow into a
  new plant

10
How Fertilization Occurs

• When a pollen grain reaches a pistil, it grows a
  thin tube to the ovary. Sperm from the pollen
  grain combines with an egg, and a seed forms.

11
What is the Life Cycle of a Flowering Plant
dormant the resting stage of a seed

• Dormant Seed
• Takes in water and the seed coat gets soft. If
  the seed has enough oxygen and the right
  temperature, it will begin to germinate.

12

• Geminating Seed
• First a root pushes through the seed coat and
  grows downward.
• The top part of the root grows upward and becomes
  the stem. The stem carries the seed coat and the
  seed leaves with it. The seed coat falls off.
  The seed leaves provide food for the plant. Two
  small leaves begin to grow from between the seed
  leaves.

13

• Seedling
• When the stored food within the original seed
  leaves is used up, they dry up and drop off.
  More leaves grow from buds on the stem as the
  plant grows taller. The new leaves can trap
  energy from sunlight and make sugar. Plants use
  the energy in the
  sugar to grow.

14
Seed and Fruit Development

• After fertilization, the petals and sepals fall
  off flower
• Ovary ripens into a fruit
• The ovule develops into a seed

15
Seed Dispersal Mechanisms-Allow plants to
colonize new areas and avoid shade of parent plant
Wind Dispersal - Flight mechanisms, like
parachutes, wings, etc. Ex. Dandelion, maples,
birch
Animal Dispersal - Fleshy fruits which animals
eat, drop undigested seeds in feces or burrs
which stick to animals coats
16
Gravity Dispersal - Heavy nuts fall to ground and
roll ex. acorns
Water Dispersal - Plants near water create
floating fruits ex. coconuts
17
Plant ResponsesCHAPTER 31

• How plants move and communicate

18
Plant Hormones
19
Plant Hormones

• Plant hormones can be divided into two classes
• Growth promoters Auxins, Gibberellins,
  Cytokinins
• Growth inhibitors Ethylene gas, Abscisic acid

20
Growth promoters

• Hormones can promote plant growth in two ways
• Stimulating cell division in meristems to produce
  new cells.
• Stimulating elongation in cells.

21
Auxin activity
Auxins stimulate genes in cells associated with
plant growth.
22
Auxin roles

• Auxins carry out multiple roles having to do with
  plant growth including
• Tropisms
• Apical dominance
• Growth of adventitious roots
• Fruit growth

23
Tropisms

• Tropisms are the growth of a plant toward or away
  from a stimulus, including
• Phototropism in response to light
• Gravitropism in response to gravity
• Thigmotropism in response to touch

24
Nastic Movements
25
Nastic movement in the sensitive plant (Mimosa
pudica)
26
Hinge control in Venus Fly Trap - Nastic movement
27
Plant Communication

• Plants communicate chemically.
• Injured plants send out chemical signals that may
• signal other plants to prepare for an attack.
• attract other insects that eat the insects that
  are attacking the plant.

28
(No Transcript)