Sexual reproduction in plants

The main parts include sepals (protect the bud), petals (attract pollinators), stamens (male parts with filament and anther), and carpels (female parts with stigma, style, and ovary containing ovules).

Wind-pollinated flowers have exposed anthers and feathery stigmas to catch pollen carried by the wind. Insect-pollinated flowers have anthers inside the flower and sticky stigmas to catch pollen from insects.

Insect-pollinated flower pollen is often large, heavy, and sticky or spiky, aiding adherence to pollinators. Wind-pollinated flower pollen is typically small, light, and smooth for easy dispersal by wind.

Fertilization occurs when a pollen nucleus (male gamete) fuses with a nucleus in an ovule (female gamete) inside the ovary. This fusion results in the formation of a zygote, which develops into an embryo.

Insect-pollinated flowers often have bright and colourful petals to attract insects visually. They also frequently produce nectar, a sugary substance that provides food for pollinators.

Seed germination requires water (to activate enzymes), oxygen (for respiration), and a suitable temperature (for optimal enzyme activity).

Self-pollination reduces genetic variation, making the population less able to adapt to new environmental challenges like diseases or climate change. With less variation, there's a lower chance that some individuals will possess traits that allow them to survive in altered conditions.

After landing on the stigma, a pollen grain germinates and grows a pollen tube down the style to the ovary. The pollen tube then enters the ovule, allowing the pollen nucleus to fertilize the egg cell.