Sexual Reproduction in Plants.

1. What is sexual reproduction?

Sexual reproduction in plants is the process where the male sex cell joins with the female sex cell to produce a seed that can grow into a new plant.

It involves:

  • Pollination

  • Fertilization

  • Seed formation

2. Parts of a Flower and Their Functions

Male Part — Stamen

Made of:

  • Anther → produces pollen grains (male gametes/sex cells)

  • Filament → holds up the anther

Female Part — Carpel/Pistil

Made of:

  • Stigma → sticky top that catches pollen

  • Style → tube leading downward

  • Ovary → contains ovules

  • Ovule → contains the female sex cell (egg cell)

3. Pollination 🌼

Definition

Pollination is the transfer of pollen grains from the anther to the stigma.

Types of Pollination

A) Self-pollination

Pollen goes to the stigma of:

  • the same flower, OR

  • another flower on the same plant

B) Cross-pollination

Pollen moves from one plant to another plant of the same species.

Advantages:

  • More variation

  • Stronger offspring

Disadvantages:

  • Depends on pollinating agents

4. Agents of Pollination

Wind Pollination

Flowers are:

  • dull

  • light pollen

  • feathery stigma

  • no scent

Examples:

  • grass

  • corn

Insect Pollination

Flowers are:

  • brightly coloured

  • scented

  • produce nectar

  • sticky pollen

Examples:

  • hibiscus

  • rose

Other agents:

  • birds

  • bats

  • water

5. Fertilization 🌱

Definition

Fertilization is the fusion of the male nucleus and female nucleus.

What happens?

  1. Pollen lands on stigma

  2. Pollen tube grows down the style

  3. Male nucleus travels down tube

  4. Joins with egg cell in ovule

  5. Fertilization occurs

6. What Happens After Fertilization?

Part

Becomes

Ovule

Seed

Ovary

Fruit

Zygote

Embryo

The seed contains:

  • embryo (young plant)

  • food store

  • seed coat

7. Seed Dispersal 🌬

Seeds are spread away from parent plant to reduce competition.

Methods:

  • Wind

  • Water

  • Animals

  • Explosion/bursting fruits

Examples:

  • coconut → water

  • dandelion → wind

8. Germination 🌱

Definition

Germination is the process where a seed begins to grow.

Conditions needed:

  • Water

  • Oxygen

  • Suitable temperature (warmth)

Some seeds also need light.

9. Important Terms

Term

Meaning

Pollen

Male sex cell

Ovule

Contains female sex cell

Pollination

Transfer of pollen

Fertilization

Fusion of nuclei

Gamete

Sex cell

Zygote

Fertilized egg

Germination

Seed starts growing

10. Differences Between Pollination and Fertilization

Pollination

Fertilization

Transfer of pollen

Fusion of nuclei

Happens on stigma

Happens in ovule

Before fertilization

After pollination

11. Why Sexual Reproduction is Important

  • Produces seeds

  • Creates variation

  • Helps plants adapt and survive

  • Allows new plants to grow

SUPER SHORT SUMMARY 📝

  1. Anther makes pollen

  2. Pollen reaches stigma (pollination)

  3. Pollen tube grows down style

  4. Male nucleus joins egg cell (fertilization)

  5. Ovule becomes seed

  6. Ovary becomes fruit

  7. Seed disperses and germinates into new plant 🌱