How would you test the presence of starch in leaves?
ScienceClass 7CBSEAnswered 27 Mar 2026
Answer
Solution:
Take two potted plants of the same kind. Keep one in the dark for 72 hours and the other in the sunlight. Perform the iodine test with the leaves of both plants as given below. 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.
Iodine test:
Put iodine solution on the leaf.
Observation:
Blue-black colour will be observed on the leaves of the plant kept in sunlight, which indicates the presence of starch.
Blue-black colour will not be observed on the leaves of plants kept in the darkroom. This indicates the absence of starch.
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