Reproduction in plants

Sexual & asexual reproduction

Sexual reproduction:Two parents Fusion of a female

& male cells (gametes)

Parent & offspring are not identical

SlowerVariation is present

in the same species

Asexual reproduction:

One parent onlyNo gametes are

produced Parent and

offspring are identical

FasterNo variation

Examples of asexual reproduction.Budding in yeast  

Nucleus replicates

Nucleus migrates to one end

Part of the cell grows into a bud

The bud separates creating a new cell

Examples of asexual reproduction. Vegetative reproduction in potato

plants

Examples of asexual reproduction.Runners in strawberry

Sexual reproduction in plants

To reproduce sexually plants have male and female reproductive organs in their flowers.

The male part is called the stamen

The female part is called the carpel

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 pollinatedHave large colored

petals with guide linesHave a scent Have a nectary on which

insects feedHave 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 scentHave 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

Ovary wall Fruit cover

Ovule Seed

Seed structure

D

Seed-fruit dispersalIf 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 dispersalOther 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 germinationOnce a seed falls onto a suitable

surface it starts to grow.Conditions required for seed

germination:1. Suitable temperature2. Oxygen3. Water