Plant Reproduction Questions & MCQ — Practice with Answers

Why do plants reproduce?

Plants reproduce to ensure the continuity of their kind. Without reproduction, a species of plant would eventually die out. Flowering plants reproduce sexually by producing seeds, which can grow into new plants that share characteristics of the parent plant.

Some plants can also reproduce through spores (such as ferns and mosses), which do not require flowers or seeds.

Pollination

Pollination is the transfer of pollen grains from the anther (male part) of a flower to the stigma (female part) of a flower of the same type. This is an essential first step in sexual reproduction for flowering plants.

Pollination can happen with the help of insects (such as bees and butterflies), wind, water, or animals (such as birds). Insects are attracted to flowers by their bright colours, sweet nectar, and scent. As they feed on nectar, pollen grains stick to their bodies and are carried to the next flower they visit.

Fertilisation and seed production

After pollination, the pollen grain on the stigma leads to fertilisation — the joining of the male reproductive cell (from the pollen) with the female reproductive cell (in the ovule, found inside the ovary of the flower). After fertilisation, the ovule develops into a seed and the ovary develops into a fruit.

It is important to understand that pollination and fertilisation are two different processes. Pollination is the transfer of pollen; fertilisation is the joining of reproductive cells that happens after pollination.

Seed dispersal

Seed dispersal is the scattering of seeds away from the parent plant. This is important because it reduces competition between the young plants and the parent plant for sunlight, water, nutrients, and space.

There are four main methods of seed dispersal:

• Wind: Light seeds or seeds with wing-like or feathery structures are carried by the wind (e.g. dandelion, angsana, lalang).
• Water: Seeds with waterproof coverings or air spaces that help them float are carried by water (e.g. coconut, nipah palm).
• Animals: Seeds with hooks or sticky surfaces cling to animal fur. Some fruits are eaten by animals, and the seeds pass through their droppings (e.g. rambutan, papaya).
• Explosive action (splitting): Some dried fruits split open suddenly and fling their seeds away from the parent plant (e.g. rubber tree, balsam).

Germination

Germination is the process by which a seed begins to grow into a new plant. For germination to occur, a seed needs three conditions: water, air (oxygen), and warmth (suitable temperature).

Importantly, seeds do not need sunlight to germinate. Sunlight is only needed after the young plant (seedling) has emerged and begins to make its own food through photosynthesis. Many seeds germinate underground where there is no light at all.

“Pollination and fertilisation are the same thing.” Pollination and fertilisation are two different processes. Pollination is the transfer of pollen grains from the anther to the stigma. Fertilisation is the joining of the male and female reproductive cells, which happens after pollination. A flower can be pollinated but not fertilised. Pollination must happen first before fertilisation can take place.

“Seeds need sunlight to germinate.” Seeds need three things to germinate: water, air (oxygen), and warmth. Sunlight is not one of them. Most seeds germinate underground in darkness. Sunlight only becomes necessary after the seedling has emerged and needs to carry out photosynthesis to make its own food. This is one of the most commonly tested misconceptions in PSLE Science.

“All flowers are pollinated by bees.” While bees are important pollinators, they are not the only ones. Flowers can also be pollinated by wind, water, butterflies, birds, and other animals. Wind-pollinated flowers tend to have small, light pollen grains and may not have bright petals or scent, since they do not need to attract insects.

“The fruit is the seed.” The fruit and the seed are different structures. After fertilisation, the ovule develops into the seed, while the ovary develops into the fruit. The fruit surrounds and protects the seed. For example, in a mango, the fleshy part we eat is the fruit, and the hard stone inside contains the seed.