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The Life of Plants - Roots and Their Functions

Grade 4CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Roots are the part of the plant that usually grow below the ground, moving away from light and towards gravity and moisture.

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There are two primary types of root systems: Taproot (a single thick main root with smaller lateral branches, e.g., Carrot, Mustard) and Fibrous root (a cluster of many thin, similar-sized roots, e.g., Grass, Wheat, Rice).

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The primary function of roots is the absorption of water (H2OH_2O) and dissolved minerals from the soil.

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Roots provide anchorage, holding the plant firmly in the soil so it doesn't get uprooted by wind or water.

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Roots prevent soil erosion by binding the soil particles together, reducing the impact of H2OH_2O and wind on the topsoil.

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Modified roots perform special functions: storage of food (Carrot, Turnip), providing extra support (Prop roots in Banyan trees), or helping in breathing (Mangroves in marshy areas).

📐Formulae

Total Root Uptake=H2O+Minerals (Nitrogen, Phosphorus, Potassium)\text{Total Root Uptake} = H_2O + \text{Minerals (Nitrogen, Phosphorus, Potassium)}

Soil Stability∝Root Density\text{Soil Stability} \propto \text{Root Density}

💡Examples

Problem 1:

Identify the type of root found in a grass plant and explain its structure.

Solution:

Fibrous Root System

Explanation:

Grass has a fibrous root system where many thin roots of roughly the same length grow out from the base of the stem. It does not have a single main root.

Problem 2:

How do roots help the plant obtain H2OH_2O even when the topsoil is dry?

Solution:

Deep growth and root hairs.

Explanation:

Taproots can grow deep into the soil to reach lower water tables. Additionally, tiny root hairs increase the surface area for maximum absorption of H2OH_2O molecules.

Problem 3:

Why can we eat roots like carrots and radishes?

Solution:

Storage of Food.

Explanation:

In some plants, the extra food prepared by the leaves through photosynthesis is stored in the roots. These are called storage roots, and they become thick and fleshy.