Question

What process you follow in your laboratory to study presence of starch in leaves?

Answer 1

First v boil the leaf in water n then in alcohol.
Then v add iodine solution to it. Areas which turned blue black would consist of starch and the areas which won't would not have starch

Answer 2

In the laboratory, ‘iodine test’ is used to determine the presence of ‘starch in leaves’.

The process is given below:

i)     The leaf is first boiled in water for ‘30 seconds’ to stop all chemical reactions.

ii)     It is then boiled in ethanol to remove the leaf colour.

iii)    The leaf is then washed in water and spread against a white background.

iv)    Iodine solution is added to the leaf with the help of a dropper.

The regions of the leaf that contains starch will turn blue-black in the presence of iodine. This is brought about by a reaction between the ‘iodine and beta’ amylose present in the starch.