Question

Describe experiment to show that light is necessary for photosynthesis

Answer 1

Experiment to show that light is necessary for photosynthesis. 

Take a plant. Don't keep it in sunlight for almost 24 hours. Ensure that no light should reach the plant. Now, after 24 hours of keeping the plant away from sunlight, pluck a leaf from the particular plant and test for starch in the leaf by using iodine solution. If starch is present in the leaf, then the leaf will turn blue-black. If starch is not present in the leaf, then the leaf will not turn into blue-black color. Starch can only be made in the presence of photosynthesis. Starch cannot be made in the absence of photosynthesis. After testing for starch in the leaf, you will find that the leaf will not turn blue-black, because not turning of the color of the leaf into blue-black shows that starch is not present in the leaf. Absence of starch means no occurrence of photosynthesis. This activity concludes that light is necessary for the process of photosynthesis. 

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