Answer :

sowmyasreemajj
AIM : To test the presence of starch in leaves.
MATERIALS REQUIRED :potted plant ,methylated spirit,leaf ,boiling tube,tripod stand,Bunsen burner,asbestos gauze,iodine solution ,petri dish.
 PROCEDURE :
 1.Let us take a leaf of a potted plant
 2. Boil the leaf in methylated spirit over a water bath till it becomes pale-white due to the removal of chlorophyll.
 3.Observe the leaf.
 4. Spread the leaf in a petri dish and add a few drops of tincture iodine / betadine solution to it .Again  observe the leaf.

OBSERVATION :The leaf turns blue black in color.
INFERENCE: The presence of starch will be indicated by a blue - black color.

Answer:

Experiment to test the presence of starch in leaves:-

  • Take two healthy green potted plants of the same type.
  • Keep one potted plant in a dark room for one or two days in order to remove all the starch from the leaves.
  • Keep the other plant in sunlight.
  • Now, take one leaf from each potted plant and put a few drops of iodine solution on them.
  • Then note down the observation.  

No blue black colour will be observed on the leaves of the plant kept in the dark room. This indicates the absence of starch. Blue black colour will be observed on the leaves of the plant kept in sunlight. This indicates the presence of starch.

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