Back to: Botany 100 Level
Hello, my brilliant Afrilearn scholar! I hope you’re having a wonderful day! Have you ever wondered how beautiful flowers turn into fruits and seeds? Think about a mango tree—before the juicy mango appears, the tree first produces flowers. These flowers play a key role in reproduction by helping plants produce seeds that grow into new plants.
Today, we’ll learn about how flowering plants (angiosperms) reproduce, the structure of flowers, how pollination happens, and the process of fertilisation. By the end of this lesson, you’ll understand why bees love flowers and how a tiny seed can grow into a mighty tree!
Sexual Reproduction In Flowering Plants (Angiosperms): Flower Structure, Pollination Mechanisms, Fertilization
Flower Structure: The Reproductive Organ of Plants
A flower is the reproductive organ of flowering plants (angiosperms). It contains male and female parts that help in reproduction. Let’s look at the main parts of a flower:
1. Male Reproductive Part (Stamen)
Anther – Produces pollen grains, which contain male reproductive cells.
Filament – A stalk that holds the anther.
2. Female Reproductive Part (Carpel/Pistil)
Stigma – Sticky top part where pollen lands.
Style – Connects the stigma to the ovary.
Ovary – Contains ovules, which develop into seeds after fertilisation.
3. Other Parts of a Flower
Petals – Brightly coloured to attract pollinators like bees and butterflies.
Sepals – Green leaf-like structures that protect the flower before it blooms.
Fun Fact: Some flowers contain both male and female parts (bisexual flowers like hibiscus), while others have only one reproductive part (unisexual flowers like pawpaw).
Pollination: How Pollen Moves from One Flower to Another
Pollination is the transfer of pollen from the anther (male) to the stigma (female). This is the first step in sexual reproduction.
Types of Pollination
Self-Pollination – Pollen from the same flower or plant lands on its stigma.
Occurs in tomato, hibiscus, and groundnut.
Ensures reproduction but produces less variation.
Cross-Pollination – Pollen from one flower lands on a different flower of the same species.
Occurs in maize, pawpaw, and mango.
Creates genetic variation, leading to stronger plants.
Pollinators that Help in Pollination:
Insects (Bees, Butterflies, Beetles) – Attracted by bright colours and nectar.
Wind (Maize, Grass, Rice) – Carries lightweight pollen.
Water (Aquatic Plants like Water Lily) – Moves pollen through water.
Birds and Bats – Pollinate plants like bananas.
Simple Analogy: Think of pollination like delivering a message—the pollen is the “letter,” and the pollinator (bee, wind, or water) is the “postman” carrying it to the stigma!
Fertilisation: The Union of Male and Female Cells
Once pollen reaches the stigma, the next step is fertilisation—the process where male and female cells unite to form a seed.
Steps in Fertilisation:
Pollen lands on the stigma and forms a pollen tube that grows down the style to the ovary.
Pollen tube reaches the ovule inside the ovary.
Male cell (from pollen) fuses with the female cell (in ovule) to form a zygote.
Zygote develops into a seed, and the ovary transforms into a fruit.
Example: In mango trees, fertilised flowers turn into mango fruits, and inside each mango, there is a seed that can grow into a new mango tree!
Why is Sexual Reproduction Important in Plants?
Ensures species survival – New plants are continuously produced.
Creates genetic variation – Helps plants adapt to different environments.
Produces fruits and seeds – Essential for food supply.
Maintains biodiversity – Supports different plant species.
Without sexual reproduction, plants would not be able to produce seeds, and many of our favourite foods—like rice, beans, and apples—would not exist!
Summary
The flower is the reproductive organ of flowering plants.
It contains the stamen (male) and carpel (female) parts.
Pollination transfers pollen from the anther to the stigma and can happen through self-pollination or cross-pollination.
Pollinators include bees, wind, birds, and water.
Fertilisation occurs when male and female cells unite to form a seed, which later grows into a new plant.
Evaluation
- What are the male and female reproductive parts of a flower?
- What is the difference between self-pollination and cross-pollination?
- Name three pollinators that help in pollination.
- What happens to the ovary after fertilisation?
- Why is sexual reproduction important for plants?
You are doing an amazing job! Just like plants need pollination to grow, you need knowledge to bloom! Keep learning, keep exploring, and see you in the next exciting lesson!
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