Think Beyond
(1) Observe the plant in the picture. It is the Coleus plant
Answer the following questions:
(a) Its leaves are not green. How does it get its food?
Answers
Answer:
Question 1. What happens to the colour of the leaf? What is the colour of the solution?
Now dip the leaf in a dilute solution of iodine for a few minutes.
Take out the leaf and rinse off the iodine solution.
Observe the colour of the leaf and compare this with the tracing of the leaf done in the beginning.
Question 2. What can you conclude about the presence of starch in various areas of the leaf?
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ANSWER
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.
Croton plants have chlorophyll but other red pigments are more in number than the chlorophyll so they are not in green in colour they can perform photosynthesis.