Page 14 - Biology_Form_3

Coordination in plants

Observation
(a) What changes do you observe?
(b) Write the observation of your experiment.

Cardboard box Shoot growing toward light
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Hole in the
box allowing
light to enter

Bench

Root growing away from light Wet cotton wool in dish
Figure 1.3: Experiment to investigate negative phototropism in roots
Conclusion
(a) Provide a conclusion for your experiment.
(b) Write a short report of the experiment.

The distribution of growth hormones region where there is a high concentration
(auxin) in plants depends on the presence of of auxin will be higher than that with low
light. Light causes more auxins to move to concentration of auxin. Therefore, the plant
the part of the plant that does not get enough will bend towards the direction of light as
light. By doing so the growth rate of the indicated in Figure 1.4 (a), (b) and (c).

Sunlight
Sunlight
The plant shoot with
Equal distribution hight auxin concentration
of auxin hormone grows faster than the side
in the shoot Auxin hormone with low concentration
before exposure moves away of auxin. This make the
to sunlight from sunlight plant grow towards light.

(a) (b) (c)
Figure 1.4: Phototropism

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BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 7 KAMISHNA 23/10/2025 11:52:28

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