Download Plant Reproduction

Lesson 15
PLANT REPRODUCTION
PLANT REPRODUCTION
Plant reproduction is the process of producing
young plants. Plants reproduce in two different
ways:
 Asexual Reproduction involves one parent
producing genetically identical plants. Each plant
is a clone or exact copy of its parents.
 Sexual Reproduction involves two parents, a male
and a female, producing genetically different
plants. The new plants are different from each
other and from the parents.

ASEXUAL REPRODUCTION
There are several reasons why seed plants find
this form of reproduction advantageous. If the
environment has been stable for many
generations, variability may not be as essential to
the survival of the species.
 Asexual reproduction which is not as complex and
requires far less energy, would be preferable.
 When colonizing a new area, finding a mate for
sexual reproduction may be difficult or impossible.

ASEXUAL REPRODUCTION

If the environment is particularly harsh, the
more delicate or susceptible organs or stages
of sexual reproduction may not be able to
survive.

Many plants which inhabit such areas as
deserts or arctic tundra only reproduce
asexually.
ASEXUAL REPRODUCTION
Root
The new dahlia plant
grows from a root
Stem
The new strawberry
plant grows from the
stem or runner of a
parent plant.
Leaf
Roots and tiny new
plants form at the
bottom of a leaf
cutting from an
African violet
NEW PLANTS FROM GRAFTING

Nursery and greenhouses workers produce new
plants by Grafting. In grafting, the stem of the
one plant grows on the root system of another
plant. Experienced nursery workers are
knowledgeable about which plants can be
grafted and different methods of grafting.
A
B
Plant A grows excellent fruit
 Plant B grows strong roots
 Grafting combines desirable qualities of two
different plants. This allows us to combine
trees that produce good fruit with trees that
have strong roots.

QUESTIONS:
Name four ways that plants reproduce asexually
 1 Roots
 2 stems
 3 Leaves
 4 Grafting


What is the advantage of grafting plants?
 we can mix the good traits of plants


SEXUAL REPRODUCTION IN PLANTS

Plants flowers contain its reproductive cells.
Many plants have both the male and female
sex organs on the same plant. In some cases
they will have male and female flowers on the
same plant or they can have both the male and
female organs on the same flower.
SEXUAL REPRODUCTION IN PLANTS

These plants are called
Hermaphrodites
. Some plants such as poplars have separate
male plants and female plants. This type of
sexual reproduction is called?
Separate Sexes

Seeds
are the product of sexual
reproduction in most plants. A seed is a
complete reproductive package that contains
an
Embryo , a food supply, and a
seed coat which protects it from Drying
Out .
Two groups of seed-bearing plants are
Angiosperms
and
Gymnosperms
.
 Flowering plants are called
Angiosperms
. Seeds form inside the Flowers .
 The seeds are enclosed in a case called a
Pod or a
shell
.
 Some angiosperms include:
Apples ,
Tomatoes , and sunflowers
.

Plants that do not produce flowers are called
gymnosperms
.
 The seeds are produced inside
Cones
.
 The seeds are not enclosed in a case but have
Coat
that protects them from dehydration.
 Some gymnosperms include:
Pine trees
and
Fir trees


Other plants such as
ferns
and
mosses reproduce sexually without bearing
seeds.
The reproductive organs of an angiosperm are
found in the
Flowers
.
 The female reproductive organ is called the
Pistil
. The pistil contains 4 parts.

The
stigma
is the sticky part that
captures the pollen grains.
 The
Style
is the stalk that supports
the stigma.
 The
Ovary
contains the ovules.
 The
Ovules
are sacs containing the
female gametes.

The male reproductive organ is called the
Stamen . The stamen contains 3 parts.
 The
Anther
is where the pollen is
produced and stored.
 The
Pollen
Grains
are cases
containing the male gametes.
 The
Filament
is a stalk that supports the
anther.

Anther
Anther
Stigma
Style
Pollen
Grains
Ovary
Filament
Ovules
POLLINATION





Pollination is the process of Pollen
Grains
from the anther reaching the
stigma
of the
Pistil
so that
seeds
can develop inside a
flower.
If the male and female gametes ( Egg and Sperm
) come from the same plant the process is called
Self
pollination.
If the gametes come from two different plants the
process is called Cross Pollination
.
In order for fertilization to occur, the pollen grain grows
and extension called a pollen Tube .
SEED AND FRUIT FORMATION

A
Zygote
is formed when a sperm
reaches an
Egg . In some plants the
ovary surrounding the zygotes develops into the
Fruit
. The fruit helps to protect and
disperse the seeds.
DISPERSAL
The transport of seeds away from the parent
plant is called
Dispersal .
 Seeds can be eaten by
Animals and fall
far away as droppings.
 Seeds can also stick to
Fur of mammals
until rubbed off.
 Seeds can also be transported by the
Wind
and by running water
.


The process by which a plant starts to grow is
called Germination
.


Gymnosperms are also called Conifers
because their seeds are formed inside cones.