Plant reproduction_New1

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Chapter 3:Lesson 2:
Reproduction in Plants:
Plant Kingdom
Non-flowering
Plants
Flowering
Plants
Non - flowering Plants
Mosses
Ferns
Gymnosperms
Do NOT produce flowers
Plant Classification
Plants
Non-flowering
Sporebearing
No
roots
Mosses
with
roots
Ferns
Naked
seeds
( cones)
Gymnosperms
Flowering: where
seeds are protected
in fruits.
Seed bearing plants:
Seeds in plants are either:
1- Gymnosperm: naked seeds, protected only
by seed coat.
2- Angiosperm: a flowering plant which has
seeds protected by a fruit.

Non- flowering, seed bearing
plants:






Conifers: plants where seeds are found in cones.
Example: pine tree (it grew from a seed).
Male pinecones : produces pollens that contain
sperms.
Female pinecones: have ovules that contain eggs .
Mature male cones release millions of pollen grains (
dust cloud) which are blown by wind & settles on
ovules when sperms from pollen fertilize the eggs
giving seeds.
Note: seeds have wings that travel by wind & when it
lands on a suitable habitat a new tree begins to grow.
Male cones
Female cones
Characteristics of Gymnosperms
.needle-shaped leaves.
.vascular tissues (transport).
.cones with reproductive
structures.
.naked seeds in female cones.
.dry places.
Seeds VS Spores:


Seeds enable plants to grow in many
environments.
Seeds ( unlike spores) don’t need water for
fertilization).
Flowering Plants:( 86%)
Have flowers instead of cones.
 They produce seeds inside fruits.
 Angiosperm: a flowering plant that has seeds
protected by fruits.
 In angiosperms :
- seed development is more complex.
-protected seed
live in all parts of the world.

Flowers:
Are the organs of reproduction in flowering
plants.
 Flowers start as buds
protected by sepals.

Parts of the flower include:

Sepals: enclose the flower bud and protect it until
it opens

Petals: are often like advertisement for flowers
they attract pollinators
Female
reproductive
organ
Male
reproductive
organ
Pistil
*Stigma
Sticky surface that collect
pollen.
*Ovary –contains ovules
after fertilization the
ovary develops into
fruit .
*ovules
(produce eggs that are
fertilized by sperms
from pollen & develop
Stamen
*Anther – makes pollen.
* Pollen tube- grows from
pollen grain. The tube
enables the sperm to
travel into ovules to
fertilize eggs.
Pollination:

Transfer of mature pollen grains from the
anther to the stigma.
-wind
-insects
-birds & other animals

When a pollen grain lands on the stigma, it
germinates and a pollen tube grows down
through the style to an ovule (egg)
flowers are adapted to attract pollinators
(insects) to them to enable transfer of pollen.
1-Sugary
nectar and
2- scent
present.
3-Brightly
coloured
petals that
lure animals.
Sticky stigma to
collect pollen
Flower Structure
Pollination
Fertilisation
Seed Dispersal
Germination
Test
Fertilization

The sperm travels through the pollen tube to the
ovule. The sperm & egg fuse forming the zygote
(fertilized egg) –this grows into the plant embryo.
The embryo is a tiny plant
that develops
in the ovules.

Ovule wall develops into a protective coat.
*The ovule forms the seed and the ovary forms the
fruit.
 A fruit is a ripened ovary
Seed dispersal:
Wind dispersal - Flight mechanisms,
like parachutes, wings.
Water dispersal - Plants
near water create floating
fruits
ex. coconuts
Animal dispersal - Fleshy fruits which
animals eat, drop undigested seeds in
feces or burrs which stick to
animals’ coats
Angiosperm life cycle:
1) Pollination.
2) Fertilization.
3) Embryo development.
4) Fruits develop.
5) Seeds disperse.
6) New plant grow.
Germination:
Seeds germinate or sprout only when
conditions are right for the embryo growth.( a
thick hard seed coat protect the embryo until
the seed germinate).
 To germinate seeds need:
1) enough hours of light.
2) Warm soil (usually Spring).
3) Water.

Germination:



1)
2)
3)
Timing for the seeds to germinate depends on the
needs of the plant.
Sometimes seeds stay in the ground for several
years before conditions are right for growth.
When the time is right:
Seed absorbs water & expand, breaking the
seed coat & embryo begins growing.
First the root emerges from the seed & begins to
anchor the embryo & take water up.
Then a shoot pushes up.
Germination:
Germination:


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The embryo growth needs energy, but from
where does the energy comes from??
Cotyledons: contain food that provides energy
until the plant can make its own food.
When leaves emerge from the ground, they turn
green, as chlorophyll for photosynthesis is
produced.
Finally, rapid growth begins.( embryo turns into
a plant seedling).
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