Back to: Botany 300 Level
Hello, my brilliant friend! I hope you’re having a fantastic day! Have you ever wondered how some plants survive in poor soils without fertilisers? Or why farmers plant legumes like beans and groundnuts to improve soil fertility? The secret lies in tiny underground partnerships between plant roots and microorganisms—mycorrhizae and root nodules! Today, we’ll learn how these structures help plants grow stronger and healthier.
Role of mycorrhizae and root nodules
What Are Mycorrhizae?
Imagine you have a best friend who helps you with schoolwork, and in return, you share your lunch with them. That’s exactly how mycorrhizae work!
Mycorrhizae (plural for mycorrhiza) are mutualistic (win-win) relationships between plant roots and fungi. The fungi grow around or inside the plant roots and help them absorb more water and nutrients, especially phosphorus. In return, the plant provides the fungi with sugars from photosynthesis.
Types of Mycorrhizae
Ectomycorrhizae – The fungi form a sheath around the root but do not enter the root cells. Common in trees like oak and pine.
Endomycorrhizae (Arbuscular Mycorrhizae) – The fungi penetrate root cells, forming tree-like structures inside. Common in crops like maize, wheat, and yam.
Functions of Mycorrhizae
Increases water and nutrient absorption, especially phosphorus.
Protects roots from diseases by blocking harmful microbes.
Helps plants survive in poor soils by improving nutrient uptake.
Without mycorrhizae, many plants would struggle to grow in nutrient-poor soils!
What Are Root Nodules?
Now, let’s talk about another amazing underground partnership—root nodules!
Root nodules are small, round structures found on the roots of leguminous plants (e.g., beans, groundnuts, and soya beans). They contain nitrogen-fixing bacteria called Rhizobia, which convert atmospheric nitrogen (N₂) into a usable form for plants.
Since plants cannot absorb nitrogen directly from the air, they rely on Rhizobia to fix nitrogen into ammonia, which the plant uses to make proteins and grow healthy. In return, the bacteria get shelter and food from the plant.
Functions of Root Nodules
Fix nitrogen from the atmosphere into a usable form.
Improve soil fertility, making it richer for other plants.
Help farmers reduce the use of chemical fertilisers.
This is why farmers rotate crops by planting legumes after cereals like maize—to naturally replenish soil nitrogen!
A Simple Story to Understand This Concept
Imagine you own a farm:
You hire a water supplier (mycorrhizae) to bring more water and nutrients.
You hire a fertiliser producer (root nodules) to make nitrogen-rich food for your crops.
Both help your plants grow healthy and strong!
Summary
Mycorrhizae are fungi that help plants absorb more nutrients and water.
Root nodules contain bacteria that fix nitrogen for leguminous plants.
Both relationships are mutualistic (win-win partnerships).
Legumes improve soil fertility, reducing the need for fertilisers.
Evaluation
- What is the main function of mycorrhizae?
- Which type of plants have root nodules?
- How do Rhizobia bacteria help plants?
- Why do farmers plant legumes in crop rotation?
- What is the difference between ectomycorrhizae and endomycorrhizae?
You are doing an amazing job! Now, the next time you see a bean plant, remember the hardworking bacteria in its root nodules! Keep learning with Afrilearn, and I’ll see you in the next exciting lesson. Stay curious and keep growing!
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