Question

Abhi covered a leaf of a potted plant with a black tape cover and kept the plant under sunlight for a few days and then tested it with iodine solution for the presence of starch. When tested, the colour of the covered leaf did not turn blue-black. What is the reason?

Answer 1

Answer:

Explanation:

The part of the destached leaf, when covered with black strip and exposed to sunlight it does not produce any starch because it cannot receive sunlight. The part of destarched lead covered with transparent strip produces starch because it can receive sunlight. when the test for starch is performed the leaf part which can produce starch turns to blue-black colour i.e transparent strip and uncovered part. When the starch test is performed, The part covered with the black tape remain colorless because it cannot produce starch and the rest of the leaf turned blue-black because that portion receives sunlight and produce starch.