Quick answer: The reproductive parts of a flower are the stamens (male) and the carpel or pistil (female). A stamen has a filament and an anther, which makes pollen grains. A carpel has a stigma, a style and an ovary, which contains ovules with the egg cell. Flowers with only stamens or only carpels are unisexual (e.g. papaya, watermelon); flowers with both are bisexual (e.g. hibiscus, mustard). After fertilisation, the ovary becomes the fruit and the ovules become seeds.
In flowering plants, the flower is the reproductive part of the plant. Its colourful petals and scent attract insects and birds, which help carry pollen, and its inner parts make the male and female germ cells.
In CBSE Class 10 Science, Chapter 7 (How do Organisms Reproduce?), the parts of a flower, the structure of the stamen and carpel, unisexual and bisexual flowers and what happens after fertilisation are frequently asked board exam topics.
What You Will Learn
- The four main parts of a flower: sepals, petals, stamens and carpel
- The structure of the stamen (male part)
- The structure of the carpel or pistil (female part)
- The difference between unisexual and bisexual flowers, with examples
- What each part of the flower becomes after fertilisation
1. Parts of a Flower
| Part | Description | Function |
|---|---|---|
| Sepals | Usually green, leaf-like; outermost | Protect the flower in the bud stage |
| Petals | Usually brightly coloured, sometimes scented | Attract insects and birds for pollination |
| Stamens | Male reproductive parts | Make pollen grains |
| Carpel (pistil) | Female reproductive part, in the centre | Contains ovules with the egg cell |
Sepals and petals are not directly involved in making germ cells. Stamens and the carpel are the reproductive parts of the flower.
2. The Stamen (Male Reproductive Part)
Each stamen has two parts:
- Filament: a thin stalk that holds up the anther.
- Anther: the top part, which produces pollen grains. Pollen grains contain the male germ cells.
3. The Carpel or Pistil (Female Reproductive Part)
The carpel is in the centre of the flower and has three parts:
| Part | Description |
|---|---|
| Stigma | The sticky top part, which receives pollen grains |
| Style | The long middle part, through which the pollen tube grows |
| Ovary | The swollen bottom part, which contains one or more ovules |
Each ovule contains an egg cell (the female germ cell).
Key point: The stamen is the male reproductive part and the carpel (pistil) is the female reproductive part of a flower.
4. Unisexual and Bisexual Flowers
| Feature | Unisexual flowers | Bisexual flowers |
|---|---|---|
| Reproductive parts | Either stamens or carpel | Both stamens and carpel |
| Examples | Papaya, watermelon | Hibiscus, mustard |
| Pollination | Pollen must come from another flower | Pollen can come from the same flower or another flower |
5. What Happens After Fertilisation?
Step 1: Pollen grains land on the stigma (pollination).
Step 2: A pollen tube grows from the pollen grain, through the style, to the ovule in the ovary.
Step 3: The male germ cell fuses with the egg cell in the ovule. This is fertilisation, and it forms a zygote.
Step 4: The flower then changes:
| Part before fertilisation | What it becomes |
|---|---|
| Zygote | Embryo |
| Ovule | Seed |
| Ovary | Fruit |
| Petals, sepals, stamens, style and stigma | May shrivel and fall off |
Remember: The ovary becomes the fruit, and the ovules become the seeds.
6. Summary Table
| Structure | Role | Key fact |
|---|---|---|
| Anther | Makes pollen grains | Pollen contains male germ cells |
| Stigma | Receives pollen | Sticky surface |
| Style | Path for the pollen tube | Joins stigma to ovary |
| Ovary | Contains ovules | Becomes the fruit |
| Ovule | Contains the egg cell | Becomes the seed |
7. Exam Tips and Common Mistakes
Exam Tip: When drawing the longitudinal section of a flower, label the anther, filament, stigma, style, ovary and ovule, as well as the petals and sepals.
Exam Tip: Learn the NCERT examples: papaya and watermelon are unisexual; hibiscus and mustard are bisexual.
Common Mistake: Mixing up what the ovary and ovule become. The ovary becomes the fruit; the ovule becomes the seed.
Common Mistake: Calling the stamen the female part. The stamen is male; the carpel is female.
Frequently Asked Questions
What are the male and female parts of a flower?
The stamen is the male part (filament and anther). The carpel or pistil is the female part (stigma, style and ovary).
What is the difference between unisexual and bisexual flowers?
Unisexual flowers have either stamens or a carpel, such as papaya and watermelon. Bisexual flowers have both, such as hibiscus and mustard.
What does the ovary become after fertilisation?
The ovary develops into the fruit, and the ovules inside it develop into seeds.
Where are pollen grains made?
Pollen grains are made in the anther of the stamen.
What is the function of the stigma?
The stigma is the sticky top part of the carpel that receives pollen grains during pollination.