Question

Describe how would you test the presence of starch in leaves.
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Answer 1

Answer:

First of all put the potted plant in dark room for 3 days. Let it utilise all it's starch which is stored.

Then, place it outside again allow the plant to perform photosynthesis. Then, plunk one leave from that plant.

Boil the leaf in water. Then, boil the leaf in alcohol.

Put some drops of iodine solution.

So, the leaf colour will change into blue where starch is stored.

Starch absorbs iodine

Answer 2

Answer: Iodine test

Explanation: What You Need:

Two plants

Beaker or glass jar

Saucepan on the stove

Ethyl alcohol

Iodine solution

Tweezers

Test for starch in plants:

Put one of the plants in the dark for 24 hours; leave the other one on a windowsill.

After 24 hours, put some ethyl alcohol in a beaker and place that in a saucepan full of water. Heat the pan until the ethyl alcohol begins to boil. Remove from the heat.

Use tweezers to dip each of the leaves in the hot water for 60 seconds. Then place them in the beaker of ethyl alcohol for two minutes or until they turn almost white. Set them each in a shallow dish.

Cover the leaves with some iodine solution and watch.

What Happened:

The hot water kills the leaf and the alcohol breaks down the chlorophyll, taking the green color out of the leaf. When you put iodine on the leaves, one of them will turn blue-black and the other will be a reddish-brown. Iodine is an indicator that turns blue-black in the presence of starch. The leaf that was in the light turns blue-black, which demonstrates that the leaf has been performing photosynthesis and producing starch.

Credits: HomeScienceTools