LE - 6 - Plant Reproduction

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Transcript LE - 6 - Plant Reproduction

Introduction to Plant
Reproduction
Introduction To Plant Reproduction
Sexual Reproduction
 Asexual Reproduction


These processes occur in seed plants, and
seedless plants.

Seed Plants

Seedless Plants
Types of Reproduction

Asexual Reproduction


Does not involve or
require the production of
sex cells.
One organism produces
offspring that are
genetically identical to it.
Examples of Asexual Reproduction
Strawberry Plant - Runner
Liverwart - Gemmae
Plantlet on Leaf
Types of Reproduction

Sexual Reproduction

Requires the production of sex cells – sperm
and egg – in reproductive organs.

Offspring produced are genetically different
from either parent organism.


In some plants, water and wind help bring the sperm
to the egg.
For other plants, animals such as insects help bring
the sperm and egg together.
Sexual Reproduction (continued)

Reproductive Organs

Male reproductive organs produce
sperm.

Female reproductive organs
produce eggs.

If a plant has both organs it can
reproduce by itself.

If organs are present on separate
plants, sperm and egg must come
together with the help of the
elements.
Sexual Reproduction (continued)

For sexual
reproduction,
plants can either
reproduce with
seeds, or without
seeds.
What is a Seed?


A structure that contains an embryo, stored food
(in the cotyledon), and a protective coat.
Because the seed is so well protected and fed,
the plant grown from it will grow faster
compared to seedless plants. Seedless plants
use spores to reproduce.
Why would the seed want
stored food and a protective
coat?
Types of Seed Reproducers
Two Types of Seed Reproducers

Angiosperms
What’s the difference?

Gymnosperms
Angiosperm

Angiosperms produce flowers which are used for
sexual reproduction.
Angiosperm

The stamen is the male reproductive
organ.

The pistil, the female reproductive
organ, contains the ovary at its base.

The appearance of a plant’s flower
can give clues about how the plant is
pollinated.

After pollination and fertilization, a
zygote forms and grows into the
plant embryo.
Parts of a Flower
Petal
Stigma
Anther
Style
Pistil
Filament
Stamen
Sepals
Ovary
Where are the seeds found?

THE FRUIT. So…fruit is like the plant’s baby.
Fact: Fruits have
seeds. Vegetables
do not. A true
vegetable is
usually a root.
(potato, carrots, onion)
Angiosperm
-
Parts of the ovule develop into the seed coat and store
food for the embryo.


Some seeds store food in cotyledons.
Other seeds store food in endosperm tissue
Angiosperm Life Cycle
A. Pollination happens when
pollen grains from the anthers
land on the sticky stigma of a
pistil.
B. The pollen tube
grows from the
pollen grain down
through the style
and into the ovary
at the ovule.
C. The sperm
travels down and
fertilizes the egg.
The zygote
develops.
Gymnosperm

Gymnosperms develop seeds in cones.
Gymnosperm

A pine tree or shrub is a
sporophyte plant that
produces male and female
cones.

A female cone has two
ovules which produce eggs.

Male cones produce and
release pollen.
Gymnosperm

When pollen blows into a female cone, fertilization and
seed formation can occur.

Seed released by a female cone can take two or three
years.
Seed Dispersal

Seeds are dispersed by wind, gravity, animals, and
water. Some seeds have trapped air which helps
them float.


Germination occurs when the seed coat swells and
breaks open.
Environmental conditions affect germination.
Plant Earth