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The Wonderful World of Plants - Stem, Leaf, and Venation

Grade 6CBSE

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

🔑Concepts

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The stem acts as a two-way traffic street, conducting water and minerals from the roots to the leaves via xylemxylem and transporting food from leaves to other plant parts via phloemphloem.

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The leaf consists of a stalk called the petiole and a broad green flat part called the lamina.

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Venation refers to the pattern of veins on the leaf. It is of two types: Reticulate (net-like pattern) and Parallel (veins run parallel to each other).

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Transpiration is the process by which water (H2OH_2O) is released from the leaves in the form of water vapor through small pores called stomata.

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Photosynthesis is the process by which green leaves prepare food using carbon dioxide (CO2CO_2), water (H2OH_2O), and sunlight in the presence of chlorophyll.

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There is a direct correlation between root types and venation: plants with taproots usually have reticulate venation, while plants with fibrous roots usually have parallel venation.

📐Formulae

6CO2+6H2O→Sunlight, ChlorophyllC6H12O6+6O26CO_2 + 6H_2O \xrightarrow{\text{Sunlight, Chlorophyll}} C_6H_{12}O_6 + 6O_2

Rate of Transpiration=Amount of H2O lostTime taken\text{Rate of Transpiration} = \frac{\text{Amount of } H_2O \text{ lost}}{\text{Time taken}}

💡Examples

Problem 1:

If you observe a leaf with a net-like design on both sides of the midrib, what type of venation is it, and what type of root system is the plant likely to have?

Solution:

Reticulate Venation and Taproot system.

Explanation:

A net-like pattern on the lamina is called reticulate venation. In Grade 6 Science, we learn that plants with reticulate venation typically possess a taproot system (a main central root with smaller lateral branches).

Problem 2:

A student covers a leaf of a potted plant with a transparent polythene bag. After a few hours, tiny droplets of H2OH_2O are seen inside the bag. Name the process.

Solution:

Transpiration.

Explanation:

Leaves release excess water into the atmosphere in the form of vapor. When trapped in a bag, the vapor cools and condenses back into liquid H2OH_2O droplets.

Problem 3:

Identify the venation in Grass and Wheat plants.

Solution:

Parallel Venation.

Explanation:

In grass and cereals like wheat, the veins run straight and parallel to one another from the base to the tip of the leaf, which is characteristic of plants with fibrous roots.