1. Let's us observe the flower carefully...

2. Parts of a Flower...
Female Part
STAMEN
PISTIL
Male Part
PETAL

3. Petal
Petals are brightly colored structures used to attract insects by their bright color & scent.

4. Stamen
Pollen Grains
Filament
Anther

5. Definitions...
Stamen: Male part of the flower; consists of 2 parts – filament & anther.
Anther: Sac-like container within which pollen grains develop.
Filament: Slender stalk that supports the anther.
Pollen/Pollen grains: The male gametes (reproductive cells) for plants.

6. Carpel... Stigma Ovary Style
One or more carpels make up the pistil , which is the female part of the flower.

7. Cross-section 1 of Carpel
Pollen Grain
Sticky Stigma
Style

8. Cross-section 2 of Carpel
Ovary
Ovules
Within each ovule is a microscopic female gamete (female reproductive cell)!!!

9. Definitions...
Carpel: Female part of the flower; consists of 3 parts – stigma, style & ovary.
Stigma: Enlarged sticky knob on the end of a style; serves to receive pollen grains.
Style: Slender stalk that connects stigma to ovary.
Ovary: Enlarged base of the carpel that contains a number of ovules.
Ovules: The female gametes (reproductive cells) also called the egg or ovum for plants.

10. Examples of unisexual flowers are: Maize, papaya & cucumber
What we have just seen is a bisexual flower, where both the male & female parts are found on a single flower.
However, there are unisexual flowers present too, where the male & female parts are found on separate flowers.
Examples of unisexual flowers are:
Maize, papaya & cucumber

11. Stamen Carpel Stamen Fruit Carpel
Male Papaya Flower
Female Papaya Flower
Stamen
Fruit
Carpel
Stamen then shed its pollen and falls off the plant. Female flower produces the cucumber fruit.
Male Cucumber Flower
Female Cucumber Flower

12. Now that we know more about flowers and flower parts, what do you think happens when a bee lands on a flower to obtain nectar???

13. Let us observe what happens when the bee lands on the flower…
I want two volunteers to come up, one with a male flower, one with a female flower…
Let us observe what happens when the bee lands on the flower…
Can anyone tell me what you did you observe happen when the bee lands on the flower?

14. Pollination takes place. Let’s take a look at how it happens…

15. OH!!! You mean like this…
When the anther is mature, it splits open and the pollen grains are released from its sac!!!
Pollen

16. These pollen grains are small and light.
When the bee lands on the flower, it will push through the anthers to get its nectar. When that happens, its body will rub against the pollen and some of it will get stuck on its body. On its way out, the pollen that’s on its body will get stuck on the sticky stigma.

17. When this (pollen landing on stigma) happens, pollination takes place.
If pollen from the anther lands on the stigma of the same plant, self-pollination occurs.

18. If the pollen from the anther lands on the stigma of another plant, then cross-pollination occurs.

19. What differences do you observe in these 2 flowers?
Pollination
can occur in 2 main ways…
By Insects
By Wind
Insect pollinated flowers are usually brightly colored, scented & produce nectar. Wind-pollinated flowers are inconspicuous, unscented & do not make nectar.
What differences do you observe in these 2 flowers?

20. Let’s find out what really happens…
Homer, what happens after pollination, when the pollen has landed onto the stigma???
Bart, fertilisation will take place in plants, just like in humans. But it will go through a different process instead…
Let’s find out what really happens…

21. Grows as it is attracted by sugar in the stigma.
Pollen Tube
Ovule
Ovary
Tip of the pollen tube is a male nucleus equivalent to the nucleus in the head of the animal’s sperm.
Micropyle

22. When the pollen tube reaches the ovule, the tip of the pollen tube breaks open to release a nucleus which fuses with the nucleus of the egg cell. Fertilisation has taken place.
Zygote develops into an embryo in the ovule.
Fertilized egg forms a zygote.
Fusion
Endosperm is the stored food in the seed for germination later.
Releases nucleus
Diagram of Ovule

23. Papaya We can see that the flower has been replaced by a fruit!
Ovary develops into a fruit
Flower turning into a fruit
Fruit
Ovule/Ovules develop into a seed/seeds.
Papaya

24. Wow… so that’s how seeds & fruits are formed…
Ovary becomes fruit
Fruit carries & protects seeds until they are released when the fruit is ripe.
Wow… so that’s how seeds & fruits are formed…
Ovules become
seeds

25. Now, seeds can be replanted to become plants again before bearing flowers, then turning into fruits as the cycle repeats itself…

26. Similarities In the sexual reproduction in animals & plants…
Both plants & animals have a male reproductive cell, called sperm in animals & a pollen grain in plants.
Both plants & animals have a female reproductive cell, called a ovum in animals & a ovule in plants.
In both animals and flowering plants, a new organism is formed when the male reproductive cell and the female reproductive cell fuse.

27. Interesting uses of flowers...
Cloves, saffron, rose petals & marigold petals are used to add flavour to the food.
Dandelion & elder- berry flowers are used to make wine.
We eat broccoli, cauliflower & artichoke
BCA flower buds, Cloves-dried flower buds, saffron from female parts of the flower
Clover, orange &
sage flowers is best for honey- making.
Flower petals of jasmine, mimosa & rose are used to make expensive
perfumes.
Petals of some brightly colored flowers are used to make colored dyes for clothes.

28. Flower Bisexual/Unisexual
Male Part:
Pollen grains in anther
Female Part:
Ovules in carpel
Pollination (Self & Cross)
Insect- Pollination
Wind- Pollination
Fertilisation
(Fusion of pollen & egg cell in ovule)
Development of fruits & seeds

29. Summary...
Understand that plants reproduce to ensure continuity of their kind.
Label the different parts of the flower.
List the respective functions of the different parts of the flower.
Know what is a bisexual & unisexual flower (& some examples).
Know the process of pollination (can occur in 2 main ways) & the features of insect & wind-pollinated flowers.
Know the process of fertilisation (how seeds & fruits are formed).
Know the similarities in the sexual reproduction in plants & animals.