Reproduction in plants

What do plants need to

survive? Water

Air (oxygen and carbon dioxide)

Sunlight

Mineral salts

Fertilizers can be added to the soil to

increase the minerals available to

plants, more minerals help plants to

grow faster and stonger.

Plant structureBud

Leaf

Stem

Root

Flower

Reproduction in plants

To reproduce plants have flowers

containing male and female reproductive

organs.

The male part is called the stamen

The female part is called the carpel or

pistil.

Pollen grains

receptacle

stalk

filament

sepal

Petal

POLLINATIONIt is the transfer of pollen grains from the anthers to the stigma

Pollinating agents

Insects Wind

Differences between insect &

wind pollinated flowers

Insect pollinated Wind pollinated

Have large colored petals with guide lines

Have a scent

Have a nectary on which insects feed

Have a sticky stigma for pollen grains to stick on it

The female and male organs are enclosed in the flower

Pollen grains are larger with spikes to hold on insect body

Have small green petals, no guide lines

Have no scent

Have no nectary

Have a feathery stigma to catch the pollen in the air

The female and male organs are hanging outside the flower

Pollen grains are smaller & light weight to be carried by wind

POLLEN GRAINS AS SEEN UNDER THE MICROSCOPE

Can you tell which belongs to insect pollinated flowers / wind pollinated flowers?

FERTILISATIONIt is the joining of male and female cells to produce a zygote.

Ovary Fruit

Ovule Seed

Seed structure

Radicle, grows

to be the root

Plumule, grows

to be the shootSeed

storage, food

that will be

used during

germination

Seed-fruit dispersal

If a seed lands next to the parent plant and

germinates it will compete with the parent

plant for nutrients in the soil.

Most plants developed methods to

scatter/disperse their seeds to ensure they

land further away from the original plant.

There are 2 main methods of seed

dispersal:

Wind dispersal

Animal dispersal

Wind dispersal

Parachute e.g. dandelion Winged fruits e.g. Acer

Animal dispersal

Hooked fruits e.g. Burdock and others

Animal dispersal Other fruits are large coloured and

fleshy/juicy to attract animals to eat them, swallowing the seeds at the same time.

The seeds have hard indigestible testa that pass out with faeces in a new area away from original plant.

Example of such fruits: apple, acorn, strawberries…etc.

Seed germination

Once a seed falls onto a suitable surface

it starts to grow.

Conditions needed for seed germination:

1. Suitable temperature

2. Oxygen

3. Water