1. Angiosperm Reproduction

2. Angiosperms Sporophyte = dominant generation Gametophytes
the large plant that we see
Gametophytes
reduced in size
Develop within flowers
depend on the sporophyte for nutrients
Male gametophytes (pollen grains)
female gametophytes (embryo sacs)
Video: Flower Blooming (time lapse)
Video: Time Lapse of Flowering Plant Life Cycle

3. Stigma Anther Carpel Stamen Style Filament Ovary Sepal Petal
LE 38-2a
Stigma
Anther
Carpel
Stamen
Style
Filament
Ovary
Sepal
Petal
Key
Haploid (n)
Receptacle
Diploid (2n)
An idealized flower

4. Germinated pollen grain (n) (male gametophyte) Anther
LE 38-2b
Germinated pollen grain
(n) (male gametophyte)
Anther
Ovary
Pollen
tube
Ovule
Embryo sac (n) (female
gametophyte)
FERTILIZATION
Egg (n)
Mature
sporophyte
plant (2n)
Sperm (n)
Zygote
(2n)
Seed
Key
Seed
Haploid (n)
Diploid (2n)
Embryo (2n)
(sporophyte)
Germinating
seed
Simple fruit
Simplified angiosperm life cycle

5. Flower Structure Flowers reproductive shoots
angiosperm sporophyte
They consist of four floral organs:
Sepals
Petals
Stamens
Carpels

6. LE 38-3a
SYMMETRY
OVARY LOCATION
FLORAL DISTRIBUTION
Bilateral symmetry
(orchid)
Lupine inflorescence
Superior
ovary
Radial symmetry
(daffodil)
Sunflower
inflorescence
Semi-inferior
ovary
Inferior
ovary
Sepal
Fused petals

7. REPRODUCTIVE VARIATIONS
LE 38-3b
REPRODUCTIVE VARIATIONS
Maize, a monoecious species
Dioecious Sagittaria latifolia (common
arrowhead)

8. Video: Bat Pollinating Agave Plant Video: Bee Pollinating
pollination
transfer of pollen from an anther to a stigma
If successful:
pollen grain produces a pollen tube
grows down into the ovary
discharges sperm near the embryo sac
Pollen
develops from microspores within sporangia of anthers
Video: Bat Pollinating Agave Plant
Video: Bee Pollinating

9. LE 38-4 Development of a male gametophyte (pollen grain)
Development of a female gametophyte
(embryo sac)
Pollen sac
(microsporangium)
Mega-
sporangium
Micro-
sporocyte
Ovule
Mega-
sporocyte
MEIOSIS
Integuments
Micropyle
Micro-
spores (4)
Surviving
megaspore
Each of 4
microspores
Female gametophyte
(embryo sac)
MITOSIS
Ovule
Antipodal
cells (3)
Generative
cell (will
form 2
sperm)
Male
gametophyte
(pollen grain)
Polar
nuclei (2)
Egg (1)
Nucleus of
tube cell
Integuments
Synergids (2)
20 µm
Ragweed
pollen
grain
(colorized
SEM)
Key
to labels
Embryo
sac
75 µm
Haploid (n)
100 µm
(LM)
Diploid (2n)
(LM)

10. Embryo sacs
develop from megaspores within ovules

11. Prevention of Self-Fertilization
self-incompatibility
ability to reject its own pollen
Pollen with S-gene matching stigma cell gene are rejected
triggers a signal transduction pathway
block in growth of a pollen tube

12. Pin flower Thrum flower
LE 38-5
Stigma
Stigma
Anther
with
pollen
Pin flower
Thrum flower

13. Animation: Plant Fertilization
Double Fertilization
Pollen lands on a receptive stigma
Produces pollen tube
extends between the cells of the style toward the ovary
pollen tube discharges two sperm into the embryo sac
One sperm fertilizes the egg
other combines with the polar nuclei
creates endosperm (3N)
Animation: Plant Fertilization

14. LE 38-6 Pollen grain Stigma Pollen tube If a pollen grain 2 sperm
germinates, a pollen tube grows down the style toward the ovary.
2 sperm
Style
Ovary
Ovule (containing
female
gametophyte, or
embryo sac)
Polar
nuclei
Egg
Micropyle
Ovule
Polar nuclei
The pollen tube
discharges two sperm into the female gametophyte (embryo sac) within an ovule.
Egg
Two sperm
about to be
discharged
One sperm fertilizes
the egg, forming the zygote. The other sperm combines with the two polar nuclei of the embryo sac’s large central cell, forming a triploid cell that develops into the nutritive tissue called endosperm.
Endosperm
nucleus (3n)
(2 polar nuclei
plus sperm)
Zygote (2n)
(egg plus sperm)

15. Animation: Seed Development
From Ovule to Seed
each ovule develops into a seed
ovary develops into a fruit
Animation: Seed Development

16. LE 38-7 Ovule Endosperm nucleus Integuments Zygote Zygote
Terminal cell
Basal cell
Proembryo
Suspensor
Basal cell
Cotyledons
Shoot apex
Root apex
Seed coat
Endosperm
Suspensor

17. Common garden bean, a eudicot with thick cotyledons
LE 38-8a
Seed coat
Epicotyl
Hypocotyl
Radicle
Cotyledons
Common garden bean, a eudicot with thick cotyledons

18. Castor bean, a eudicot with thin cotyledons
LE 38-8b
Seed coat
Endosperm
Cotyledons
Epicotyl
Hypocotyl
Radicle
Castor bean, a eudicot with thin cotyledons

19. Pericarp fused Scutellum with seed coat (cotyledon) Endosperm
LE 38-8c
Pericarp fused
with seed coat
Scutellum
(cotyledon)
Endosperm
Coleoptile
Epicotyl
Hypocotyl
Coleorhiza
Radicle
Maize, a monocot

20. Animation: Fruit Development
From Ovary to Fruit
fruit = ripened ovary
protects the enclosed seeds
aids in seed dispersal by wind or animals
fruit are classification
Simple
Aggregate
Multiple
Animation: Fruit Development

21. Ovary Stamen Stigma Ovule Pea flower Seed Pea fruit Simple fruit
LE 38-9a
Ovary
Stamen
Stigma
Ovule
Pea flower
Seed
Pea fruit
Simple fruit

22. Carpels Stamen Raspberry flower Carpel (fruitlet) Stigma Ovary Stamen
LE 38-9b
Carpels
Stamen
Raspberry flower
Carpel
(fruitlet)
Stigma
Ovary
Stamen
Raspberry fruit
Aggregate fruit

23. Pineapple inflorescence
LE 38-9c
Flower
Pineapple inflorescence
Each
segment
develops
from the
carpel
of one
flower
Pineapple fruit
Multiple fruit

24. Seed Germination Dehydration of seed Dormancy
increases the chances that germination will occur at a time and place most advantageous to the seedling

25. Foliage leaves Cotyledon Epicotyl Hypocotyl Cotyledon Cotyledon
Radicle
Seed coat
Common garden bean

26. LE 38-10b
Foliage leaves
Coleoptile
Coleoptile
Radicle
Maize

27. Reproduction Sexual reproduction Asexual reproduction
generates genetic variation
makes evolutionary adaptation possible
Asexual reproduction
called vegetative reproduction
Mechanisms
Fragmentation
separation of a parent plant into parts that develop into whole plants
adventitious shoots
a parent plant’s root system gives rise to adventitious shoots that become separate shoot systems

28. Agriculture Vegetative Propagation Grafting
asexual reproduction from plant fragments (cuttings)
Grafting
A twig or bud can be grafted onto a plant of a closely related species or variety

29. Artificial Selection Humans intervention as a selective force
Ex. Maize
Hybridization

31. Reducing World Hunger and Malnutrition
Genetically modified plants may:
increase the quality of food
Increase quantity of food worldwide

33. Genetically modified rice
LE 38-16
Genetically modified rice
Ordinary rice