Plant Reproduction

Plant Reproduction
Angiosperms (flowering plants)
• Plants that protect their seeds within the body
of a fruit.
• Make up ¾’s of all plants, including:
– Trees, shrubs, herbs,
grasses, water plants…
Structure of a Flower
1. Pistil
2. Stigma
3. Style
4. Ovary
5. Stamen
6. Filament
7. Anther
8. Petal
9. Sepal
10. Receptacle
11. Stem
Male Reproductive Structure
The stamen consists of
two parts: Anther and
The anther is where
meiosis occurs to
produce haploid pollen
The filament is a stalk
that supports the
Female Reproductive Structure
The pistil consists of
the stigma, style and
The sticky stigma
receives the pollen
from the anther
The pollen grows a
tube down through the
Meiosis occurs in the
ovary to produce
haploid ovules
Reproductive Structures
• Petals: colourful
structures that attract
• Sepals: surround and
protect the flower bud.
Wind, insects or other
animals transfer pollen
from the anther of one
flower to the stigma of
Flowers vary
depending on
pollination mechanism
Pollination Animation
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 Pollination:Rank odor, flesh
colored petals
• Pollen Grain
• Anther Sac
Pollen grains contain two haploid cells produced through meiosis.
1- The Tube cell – will grow the pollen tube.
2- The Generative cell – will go through mitosis to create
two sperm cells.
Each ovule within an ovary has a micropyle (an opening for the
pollen tube).
The ovules’ megasporangium undergo meiosis to produce four
haploid cells (3 die leaving 1 megaspore)
The megaspore undergoes mitosis 3 times to produce 8 haploid
cells within the embryo sac.
After pollen lands on the stigma, a pollen
tube grows down through the style to ovary
Generative cell creates the two sperm nuclei
Double fertilization occurs:
one sperm fertilizes the egg
 one sperm the two polar nuclei together
Result of Double Fertilization
The sperm nucleus and egg nucleus join to
form a 2n (diploid) embryo
The other sperm nucleus and the two polar
nuclei join to form a 3n (triploid)
endosperm. The endosperm is the food
supply for the embryo.
First link
Seed and Fruit Development
After fertilization,
the petals and
sepals fall off
Ovary “ripens”
into a fruit
The ovule
develops into a
Seed Dispersal MechanismsAllow 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
Gravity Dispersal Heavy nuts fall to
ground and roll
ex. acorns
Water Dispersal - Plants
near water create floating
ex. coconuts