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NCERT Solutions Curiosity Chapter 10 .3 Growth and Movement in Plants — In-text Questions

Book page 19110 Updated on2026-09-05

Q1.
How do plants respond to sunlight? Does sunlight affect the direction of growth of different parts of plants?
Answer

Plants respond to sunlight by growing towards it — and yes, sunlight does affect the direction of growth, but only of the shoot.

  • A shoot bends and grows towards the light. Keep a money plant beside a window for a fortnight and all its leaves face the window.
  • A root does not follow the light at all. It keeps growing downwards, into the soil where the water and minerals are.
  • Leaves turn so that their flat surface faces the light and catches as much of it as possible.
  • A sunflower head follows the Sun from east to west during the day while it is young.
Why the shoot chases light and the root ignores it: the shoot carries the leaves, and leaves must have sunlight to make food — so bending towards light is directly useful. The root has a different job: to anchor the plant and take in water and minerals. Both are found below, so the root answers to gravity instead of light. Activity 10.3 is designed to demonstrate exactly this split.
Check it yourself: put a potted tulsi on a window sill and turn the pot half-way round every fourth day. The shoot tips will keep re-bending towards the glass each time. Nobody is moving them — the plant is responding.
Q2.
In which direction would the root and shoot of a plant grow and move if the plant is placed inverted? How would you design an activity to find answers to these questions?
Answer

My prediction: even if the plant is turned upside down, the root will bend and grow downwards and the shoot will bend and grow upwards. The plant will “correct” itself.

How to design the activity — the plan the book follows in Activity 10.3:

  1. Grow the seedlings. Germinate bean or gram seeds on a moist cloth until each has a small root and a small shoot.
  2. Make three identical set-ups so that the comparison is fair — label three glass beakers A, B and C.
  3. Mount one seedling on each glass plate lined with thick blotting paper, tied with soft cotton thread so the plant is not damaged. The wet blotting paper supplies moisture.
  4. Change only one thing in each — that is the heart of the design:
    • A — seedling upright, sunlight from all directions. This is the control.
    • B — seedling inverted (shoot pointing down, root pointing up), sunlight from all directions. Tests the effect of the plant's own position.
    • C — seedling upright, but light entering through one small hole in a cardboard box. Tests the effect of the direction of light.
  5. Predict first, then observe for several days and record both in a table, so you can honestly compare the two.
Why three set-ups and not one: with only beaker B you could not tell whether the bending was caused by the inversion or was just how that seedling grew. A is the ordinary case to compare against, and C separates the effect of light direction from the effect of plant position. Change one factor at a time — that is what makes it an experiment rather than a demonstration.
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