Q.3 How would you test the presence of starch in leaves?

The presence of starch in leaves can be tested by the Iodine test.

1.Take two potted plants of the same kind- for example, money plants or crotons.
2. Keep one in the dark for 72 hours and the other in sunlight.
3. Perform the iodine test with the leaves of both plants.
Iodine test-To put iodine solution on the leaf.
4.Now leave the pot which was earlier kept in the dark, undisturbed for 3 – 4 days,
and perform the iodine test again on its leaves.

Observation:

1.Blue-black color will be observed on the leaves of the plant kept in sunlight,
which indicates the presence of starch.
2.Blue-black color will not be observed on the leaves of plants kept in the darkroom.
This indicates the absence of starch.