REPRODUCTION IN

FLOWERING PLANTS

The Parts of a Flower

In a typical flower, there are four main parts:

Petals, sepals, stamen and carpel.

There are two main types of flower:

Insect- pollinated flowers

Wind- pollinated flowers

CHAPTER 2

REPRODUCTION IN FLOWERING PLANTS

THE FLOWER STRUCTURE

stigma

style

ovary

ovule

carpel

anther

filament

stamen

petal

sepal

receptaclepeduncle

Flower Structure Pollination Fruit Development Seed Dispersal Germination Test

• What is the name of the structure labelled X in the diagram?

sepal

stamen

peduncle

carpel

X

FLOWER STRUCTURE QUIZ• Where is pollen made?

stigma

sepal

anther

ovary

FLOWER STRUCTURE QUIZ• Where is the ovule found in a flower?

petals

style

nectary

ovary

Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

• Which parts of the flower are labelled below:

X = filament, Y = anther

X

YX = stigma, Y = style

X = anther, Y = filament

X = style, Y = stigma

Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

1. Petals (corolla): often with bright color, pattern

and scent to attract insects and birds.

2. Carpels(female gametes):

Stigma :sticky surface that collects pollen

Style : a neck that joins the stigma to the ovary

Ovary : part of the ovary that produces ovules

3. Stamen (male gametes):

anther :head of the stamen that contain pollens grain

Filament : long stalk to supports the anther

4. Sepals ( calyx): leaves that protect the young flower

buds

Pollen can be transported from the anther

to the stigma by insects, birds

or other animals, wind and water,

INSECT-POLLINATED FLOWERS ARE ADAPTED TO

ATTRACT INSECTS TO THEM TO ENABLE TRANSFER

OF POLLEN

Sticky stigma to

collect pollenBrightly coloured

petals

nectar and a scent

present

Pollen has

barbs for

hooking onto

insect fur

Anthers positioned to

rub pollen onto insects

WIND-POLLINATED FLOWERS ARE DIFFERENT IN

STRUCTURE BECAUSE THEY DO NOT HAVE TO

ATTRACT INSECTS TO THEM BUT DO NEED TO BE

EXPOSED TO THE WIND.

Petals are small and

green as there is no

need to attract insects

Stigma are feathery

to catch pollen

carried on wind

Anthers are exposed to the wind

so that pollen can easily be

blown away

Pollen grains are very small

and light. They occur in very

large numbers

No scent or nectary

Self-Pollination and Cross-pollination

Self –pollination: if the pollen goes from an anther to the

stigma of the same flower or other flowers on the same

plant.

Cross-Pollination: it the pollen goes from an anther to

stigma of a flower on other plant of the same species.

SELF-POLLINATION OCCURS WHEN POLLEN FALLS

FROM THE ANTHER ONTO THE STIGMA OF THE

SAME FLOWER

• Self-pollination is not desirable as it reduces variation

• Click to show animation of self-pollination

Flower Structure Pollination Fertilisation Seed Dispersal Germination Test

POLLINATION QUIZ

• Pollination is the transfer from….?

the stigma to anther

style to stamen

anther to stigma

ovule to filament

POLLINATION QUIZ

• The two mechanisms for pollination are?

Wind and water

Insect and water

Insect and wind

Wind and birds

POLLINATION QUIZ

• Cross-pollination…

Increases variation

Decreases variation

Is only performed by wind

Is only performed by insects

POLLINATION QUIZ

• Flowers are adapted for wind-pollination by…

Having feathery stigmas

Having a nectary

Having bright petals and a scent

Having sticky stigmas

Fertilisation

When a pollen grain reaches the stigma, a small tube forms

and grows down into the ovary. The pollen cells travel down

this tube until they reach the ovary.

When a male pollen cell reaches the ovary, it joins with a

female ovule to fertilise it.

ONCE POLLINATION OCCURS A TUBE GROWS

FROM THE POLLEN GRAIN DOWN THROUGH THE

STYLE TO THE OVULE

Flower Structure Pollination Fruit Development Seed Dispersal Germination Test

stigma

style

ovary

ovule

carpel

Note: Petals not shown in order to

simplify diagram

Click to view the

animation

FERTILISATION OCCURS WHEN THE MALE GAMETE

FUSES WITH THE OVULE (THE FEMALE GAMETE)

Complete the

fertilisation section

of the worksheet

(you will need to

refer to your text

book)

Flower Structure Pollination Fruit Development Seed Dispersal Germination Test

Click to view the

animation

Dispersing the fruits and seeds

A plant produce many fruits. If they were all fall to

the ground around their parent, they would

compete with each other for light, water and

minerals in the soil, and so many would die.

Over crowding is prevented by fruit and seed

dispersal.

SEEDS NEED TO BE DISPERSED AWAY FROM THE

PARENT PLANT IN ORDER TO REDUCE COMPETITION

FOR SPACE, LIGHT, NUTRIENTS AND WATER.

• Seeds can be dispersed by:

• Wind

• Water

• Mechanical

• Animals