drm biology y10 1 plant reproduction the plant cycle asexual reproduction sexual reproduction: ...

DRM Biology Y10DRM Biology Y10 11

Plant reproductionPlant reproductionThe plant cycleThe plant cycleAsexual reproduction Asexual reproduction Sexual reproduction:Sexual reproduction:

The flower The flower PollinationPollinationFruit and seed formationFruit and seed formationSeed dispersalSeed dispersalSeed germinationSeed germination


The plant cycle in non The plant cycle in non flowering plantsflowering plants


The plant cycle in The plant cycle in flowering plantsflowering plants


Asexual reproduction in Asexual reproduction in plantsplants

By stolons and runners (as in grasses)By stolons and runners (as in grasses) By spores (as in ferns and mosses)By spores (as in ferns and mosses) By tubers (as in potatoes)By tubers (as in potatoes) By bulbs (as in onions)By bulbs (as in onions) By grafts (used mostly in gardening)By grafts (used mostly in gardening)

In this case, all individuals are In this case, all individuals are

genetically identical to the parent plant.genetically identical to the parent plant.


Examples of asexual Examples of asexual reproduction in plantsreproduction in plants

Fern spores

stolons

tubers bulbs


Sexual reproduction in Sexual reproduction in

flowering plantsflowering plants Plants produce reproductive organs called Plants produce reproductive organs called

flowersflowers. . These flowers have These flowers have specialised structuresspecialised structures

which are either which are either femalefemale or or malemale.. Sexual cells calledSexual cells called gametesgametes are made in the are made in the

reproductive organs. reproductive organs. The gametes fuse in a process called The gametes fuse in a process called

fertilisationfertilisation. . Following fertilisation, fruits and seeds develop Following fertilisation, fruits and seeds develop

from parts of the former flower.from parts of the former flower.


Parts of the flowerParts of the flower


Parts of the Parts of the flowerflower

petal

stigma

style

ovaryovule

anther

filament

sepal


PollinationPollinationIt is the It is the transfertransfer of of

the pollen grain the pollen grain from the anther to from the anther to the stigmathe stigma..

This can be done in This can be done in the the same flower same flower (self-pollination)(self-pollination) or or in different flowers in different flowers (cross-pollination).(cross-pollination).


Wind-pollinated flowersWind-pollinated flowers

Flowers are usually very Flowers are usually very small, with no petals and small, with no petals and no scent.no scent.

Anthers and stigmas are Anthers and stigmas are exposed to the wind.exposed to the wind.

Stigmas are hairy or Stigmas are hairy or feathery to trap the pollen feathery to trap the pollen grains blown by the wind.grains blown by the wind.

Pollen grains are smooth, Pollen grains are smooth, light and very small to be light and very small to be easily carried by the windeasily carried by the wind..

Example: grassesExample: grasses

stigma

anther


Insect-pollinated flowersInsect-pollinated flowers

Have big, Have big, colourful colourful petalspetals to attract to attract insects.insects.

Have Have nectarnectar and/or and/or scentscent to attract to attract insects or insects or hummingbirds.hummingbirds.

Stamen and stigmas Stamen and stigmas inside the corolla.inside the corolla.

Pollen grains are big, Pollen grains are big, and with hooks to and with hooks to attach to insect’s attach to insect’s legs.legs.


FertilisationFertilisation

The pollen grain grows The pollen grain grows a a pollen tubepollen tube which which will will carry the nucleus carry the nucleus of the male gameteof the male gamete to to the ovule, to meet the the ovule, to meet the female egg cell.female egg cell.

Fertilisation is the Fertilisation is the fusion of the fusion of the nucleus nucleus of the male gamete of the male gamete with the nucleus of with the nucleus of the female gamete.the female gamete.


Fruit and seed formationFruit and seed formation

Once fertilised,Once fertilised, The OVARY The OVARY

develops into the develops into the FRUIT.FRUIT.

The OVULES The OVULES become the SEEDbecome the SEED..

The petals, stamen The petals, stamen and stigma shrivel and stigma shrivel and fall.and fall.


Fruit and seed dispersalFruit and seed dispersal

Seeds need to be Seeds need to be dispersed away from dispersed away from the parent plant. the parent plant.

This can be achieved This can be achieved by wind, water, by wind, water, animals, or self-animals, or self-explosion.explosion.

Each seed has Each seed has special structures special structures adapted to the way it adapted to the way it is dispersed.is dispersed.


Seed structureSeed structure Seeds are

protected by the testa.

All seeds have a food reserve (cotyledon).

The embryo is formed by the plumule and the radicle.

Plumule (future shoot)

Radicle (future root)

cotyledon

Testa (seed cover)

cotyledon

EMBRYO

Radicle

Plumule Testa


Seed Seed germinationgermination

All seeds must have water, suitable temperature and oxygen to germinate. Some seeds may also need light to activate the germination process.

Germination in a monocot plant (wheat)

Germination in a dicot plant (bean)

drm biology y10 1 plant reproduction the plant cycle asexual reproduction sexual reproduction: ...

Documents