Question

A plant is kept in the dark for two days. A leaf is used in an experiment to investigate the effect of two factors on photosynthesis as shown in the diagram. What are the colours of Q and R , when the leaf is tested for starch, using iodine solution?

Answer 1

Explanation:

Hope so it is clear to you !!

Answer 2

Answer:

For photosynthesis to occur, both sunlight and CO2 are required. The plant forms glucose (later on converted to starch) through photosynthesis. The part Q of leaf was covered and not exposed to light and part R was kept in absence of CO2. Thus, both parts of leaf did not form starch and gave a negative test for starch. (Note - iodine solution gives a positive test for starch and turns blue-black in colour)