Question 193 marksShort AnswerSection B

Define geotropism. Draw a labelled diagram of a plant showing geotropic movements of its parts.

Control and Coordination
Plant Movements - Geotropism

Official answer

Definition of Geotropism

Geotropism is the directional growth movement of plant parts in response to the pull of earth or gravity.

  • The upward growth of shoots away from the earth is called negative geotropism.
  • The downward growth of roots towards the earth is called positive geotropism.

Labelled Diagram of Geotropism

Below is the diagrammatic representation of a plant showing geotropic movements:


``diagram {"xrange": [-36.8, 446.8], "yrange": [-227.4, -47.6], "polygons": [{"points": [[150.0, -100.0], [230.0, -100.0], [230.0, -150.0], [150.0, -150.0]]}], "lines": [{"from": [400.0, -100.0], "to": [400.0, -160.0], "label": ""}], "points": [{"x": 190.0, "y": -130.0, "label": ""}, {"x": 320.0, "y": -65.0, "label": ""}, {"x": 320.0, "y": -80.0, "label": ""}, {"x": 10.0, "y": -195.0, "label": ""}, {"x": 10.0, "y": -210.0, "label": ""}, {"x": 400.0, "y": -185.0, "label": ""}]} ``

Answer keywords:geotropismgravityroots downwardsshoots upwardspositive geotropismnegative geotropism

Marking scheme

  1. 1.Define geotropism as the growth of plant parts in response to gravity. (1 mark)
  2. 2.Clearly distinguish between positive geotropism (roots growing downwards) and negative geotropism (shoots growing upwards). (1 mark)
  3. 3.Draw a neat, correctly labelled diagram showing a horizontal plant with shoot bending up and root bending down. (1 mark)

Hint

Remember that 'geo' refers to earth/gravity. Roots go down with gravity, and shoots go up against it.

Quick oral answer

Geotropism is the growth of plant parts in response to gravity. Roots show positive geotropism by growing downwards, while shoots show negative geotropism by growing upwards.

Common mistakes

  1. 1.Confusing geotropism with phototropism.
  2. 2.Drawing a normal vertical plant instead of a horizontal setup, which makes it harder to demonstrate the bending response to gravity clearly.
  3. 3.Forgetting to label 'positive' and 'negative' geotropism on the diagram.

Analysis and explanation

Geotropism is a classic example of a tropic (directional) movement in plants where gravity acts as the environmental stimulus. The NCERT textbook states that roots always grow downwards (towards gravity, showing positive geotropism) to anchor the plant and absorb water/nutrients, while shoots grow upwards (away from gravity, showing negative geotropism) to reach sunlight for photosynthesis. When a potted plant is placed horizontally, the shoot bends upwards against gravity, and the root bends downwards towards gravity, demonstrating this phenomenon clearly.

Interesting facts

Even in outer space (microgravity), scientists study plant growth to see how roots and shoots orient themselves without a strong gravitational pull!

Question details

Q19 of 30 questions

Board
CBSE
Class
Class 10
Subject
Science
Year
2020
Section
Section B
Marks
3
Type
Short Answer
Chapter
Control and Coordination
Topic
Plant Movements - Geotropism
Bloom's level
Remembering
Syllabus topic
Coordination in plants: Tropic movements in plants

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Frequently asked questions

How many marks does this question carry in CBSE Class 10 Science 2020?

This question carries 3 marks in the CBSE Class 10 Science 2020 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Control and Coordination" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Plant Movements - Geotropism" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2020 paper?

This is a Short Answer question from Section B in the CBSE Class 10 Science 2020 paper.