PSLE Science Notes: How Plants Have Babies (Plant Reproduction)
In today’s article, I am going to tell you more about Plant Reproduction [P5 Science] using this question from Raffles Girls’ Primary School Prelims 2022.
Before we get started on the question, it is important to understand the processes of plant reproduction first 😊
You’ve probably heard the saying, “An apple a day keeps the doctor away.” We all know apples are packed with fiber, vitamin C, and antioxidants. But did you ever wonder where apples come from? They actually grow from an ovary in a flower! Now, let’s learn about the fascinating processes that make all this apple goodness possible!
As a plant grows and develops into an adult, the plant starts to bloom with beautiful flowers. Within these flowers, two crucial processes unfold.
Plant Reproduction Process #1: Pollination
Pollination is the process where pollen grains from an anther of a flower is transferred to a stigma of another flower. Let’s recall the female and male parts of the flowers!
Pollination takes place with the help of wind or animals. Special characteristics of flowers play a key role in facilitating the transfer of pollen.
| Wind-pollinated flowers | Animals-pollinated flowers | |
|
 |
|
| Stigma | Feathery and hangs outside the flower to catch floating pollens | Sticky to collect pollen from pollinators |
| Anther | Hangs outside of the flower to release pollen grains easily | Located inside the flowers, brushes against the body of the pollinators |
| Pollen | Light and small | Sticky |
| Nectar | No nectar | Has nectar |
| Scent | No scent | Has scent |
Plant Reproduction Process #2: Fertilization
Following pollination, the pollen develops a tube within the style. The pollen travels down the tube, towards the ovary and ovules. Fertilization is the process where the male sex cell in the pollen fuses with the female sex cell in the ovary.
Upon fertilization, the ovary swells to become the fruit and ovules become seed. As the fruit grows, the petals wither and drop off.
What happens after that?
Seed Dispersal
Seeds germinate into baby plants when conditions are right. To avoid overcrowding and intense competition for essential resources like water, light, space, and nutrients, plants disperse their seeds far away from the parent plant.
Let’s apply the Plant Reproduction concept that we’ve learnt (Raffles Girls’ Primary School 2022 P6 Prelim)
The diagram below shows the cross-section of a flower from a plant. It has a sweet-smelling scent and brightly coloured petals.
Substances M were found on the stigma. Substances M were from another flower of the same type of plant.
(a) How did the substances M end up on the stigma of the flower? [1]
Step 1: Identify what is substance M.
Find clues from the question! Substance M was transferred from another flower and stick onto the stigma.
Substances M are the pollen grains!
Step 2: How is the flower pollinated?
Again, find clues from the question! The flower has a sweet-smelling scent and brightly coloured petals, which attracts insects such as bees. Hence, the flower is pollinated by animals.
Combine these together and you will get your answer!
Ans: Pollinators such as insects are attracted to the flower by its sweet smell and brightly coloured petals. As the insect is feeding on the nectar, substance M is transferred from the anther to the insect’s body. When the insect visits another flower, its body brushes against the stigma, transferring substance M.
Moving on to Part B…
(b) Identify the process that needs to take place before the ovule can develop into seeds inside the fruit. [1]
Remember to highlight the key words from the question!
Ans: Pollination (WRONG ANSWER)
This answer is incorrect as this is not the process right before ovules develop into seeds.
Ans: Fertilization
Part C is about Seed Dispersal!
The diagram shows how the seeds in the fruit of the plant were dispersed.
(c) State one advantage and one disadvantage of this dispersal method. [2]
Step 1: Identify the dispersal method.
From the diagram, we can see a pod structure that dries up. Hence, we can conclude that the seeds are dispersed by splitting.
Step 2: Compare splitting method with other methods
Unlike the other three methods, splitting is the only method which does not require external assistance. The success of seed dispersal by wind, water or animals depends on whether wind, water or animals are present respectively. This is the advantage of splitting!
The main objective of seed dispersal is to send the seed far away from the parent plant. Comparing to the other three methods, splitting is not the best way because it can lead to too many baby plants close together. This causes more competition for water, space, light and nutrients and increase chance of overcrowding.
Ans: The advantage of splitting is that the seeds do not need external agents for dispersal. However, the seeds are dispersed near to the parent plant. This will cause overcrowding with more competition for water, space, light and nutrients among the baby plants.
Do you know these fun facts about plant reproduction?
Other than wind and animals, flowers can also be pollinated by hands! This means the manual transfer of pollen from one flower to another with the help of human. Just by using a tiny brush, we can also help to pollinate flowers!
Apple Trees
Now, are you able to identify how are the flowers of an apple tree pollinated?
How are the seeds of an apple tree dispersed?
Found this Plant Reproduction Concept Guide Useful?
We hope this article has provided your child with valuable insights into crafting accurate and comprehensive answers for PSLE Science questions on Plant Reproduction. By mastering techniques for analyzing questions related to this topic, they can tackle exam questions with greater confidence and precision.
Ready to boost your child’s understanding of Plant Reproduction? Drop us a WhatsApp to enroll them in our Primary Science tuition class today! Gain targeted exposure to Plant Reproduction concepts and related exam questions, ensuring your child is well-prepared for PSLE success.
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