Plant Reproduction

Plant Reproduction

Asexual Reproduction in Plants

• Involves only one parent plant

• Does not involve gametes (sex cells) so no fertilisation takes place

• New plants are genetically identical to each other and the parent plant

Sexual Reproduction in plants:

• Involves two parent plants

• Each parent plant produces gametes which fuse during fertilisation

• New plant is not genetically identical to parent plants

Method of Asexual ReproductionExamples of Plants that reproduce asexually:

• Strawberry• Daffodil• Tulip

• The strawberry produces a new stem at the base of the parent plant that grows across the surface of the ground.• This new stem is called a runner.• At certain places where the runner touches the ground it produces new roots and a new shoot.

Main Parts of a Flower

carpel

Carpel

Ovary

The carpel consists of the:

• Stigma: where pollen lands• Style: connects stigma to ovary• Ovary: contains ovules which produce the female gamete, the egg

The stamen consists of the:

• Anther: produces pollen which contains the male gamete • Filament: supports anther

Ovary

Stages of Sexual Reproduction in Plants

(1) Pollination

(2) Fertilisation

(3) Seed (and fruit) formation

(4) Seed (and fruit) dispersal

(5) Germination

(1) PollinationPollination: is the transfer of pollen from the stamen to thecarpel.

Two methods:

(1) Wind pollination: AnthersHang outside plant and wind Blows pollen to carpel of another plant

(2) Insect pollination: insects such as bees pick up pollen on anther of one plant and carry it to carpel of another plant

(2) FertilisationFertilisation: is the fusion of a male gamete with a femalegamete to make a zygote.

(1) Pollen lands on carpel and a tube, called the pollen tube, grows down the style into the ovary.

(2) The male gamete passes from the pollen tube into an ovule and fuses with an egg to form a zygote.

(3) The zygote can develop into anew plant.

(3) Seed and Fruit Formation• Once fertilisation has occurred,

the fertilised ovule becomes a seed.

• The sepals, stamens and petals fall off the flower.

• The ovary swells up and becomes the fruit. The fruit protects the seeds.

Seed Structure

Testa: Protective coatsurrounding seed

Plumule: baby shoot

Radicle: baby root

Food supply: providesenergy for seed to grow

Food supply

(4) Seed Dispersal• The seed must be dispersed away from the parent plant to

prevent competition for light, water, minerals and space.

Method of Dispersal Examples of Plants Feature of Fruit/Seed

Wind DandelionGrasses

Seeds/fruits are light. May have wings/hairs

Animal RaspberryBlackberry

Fleshy and tasty fruit

Water Water lilyDuck Weed

Light and buoyant to float

Self PeasWallflowers

Have pods which explode to release seeds

(5) Germination

Germination: is the growth of a seed into anew plant.

Conditions necessary for germination:• Water• Oxygen• Correct Temperature

Mandatory Experiment: To Investigate the Conditions Necessary For Germination