Page 16 - Biology_Form_3

Coordination in plants

Importance of geotropism
Geotropism is important to plants because
of the following reasons:
(a) It enables the plants to extend roots
into the ground; hence, anchoring
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the plant firmly into the soil. This
enables plant roots to absorb water
and mineral salts from the soil. See

Negative geotropism Figure 1.6.
Positive geotropism (b) Negative geotropism exhibited by
the shoot enables the shoot to grow
Figure 1.6: Geotropism upwards, exposing the plant leaves
to sufficient sunlight for effective
photosynthesis.
Experiment 1.3

Investigation of geotropism in shoots and roots
Aim: Investigating the effect of gravitational pull on plant seedlings

Materials

Two germinating bean seeds which are at the similar stage of growth, clinostat, two
benches,board and cardboard box

Procedure
1. Place one bean seedling in a cardboard labeled “A” in such a way that the shoot
and the root are in horizontal position.

2. Take the second bean seedling and place in a cardboard labeled “B” with a slowly
rotating clinostat in such a way that both root and shoot are in horizontal position.
The clinostat ensures that there is equal pull of gravity in all direction.

3. Supply light equally to both cardboards.
4. Leave the setting for three days then remove the cardboards and observe the
seedlings carefully.
Observation

(a) What changes do you observe?

(b) Write the observation of your experiment.

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