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The starch in a variegated Coleus leaf is stored in the pigmented parts of the leaf. Coleus is a flowering plant is usually considered an ornamental plant because of its color.
It is to kill the cytoplasm, denaturate the enzyme and makes the leaf become more permeable to the iodine solution, therefor, we have to boil a leaf for starch test
boil it in water then put it in ethanol then put iodine on it the leave will tiurn dark if photosynth is occurring
coleus amboinicus
Coleus blumei Benth.
To stop or slow down transpiration
so the waxy cuticles can rub off the surface of the leaf. a leaf has a cell wall and if you did not put the leaf in the boiling water it would not break down so therefore you would not be able to do a proper starch test on the leaf so the answer to this question is to break the cell wall down so you can test for starch properly i hope i helped you :) yeap
When the plant is kept in sunlight the starch is formed in leaf.
Ethanol dissolves chlorophyll hence further phtosynthetic activity is stopped in the abscence of light and the leaf becomes transparent (colorless). the colorless leaf takes better stain with iodene while testing for the presence of starch.
Simple it doesn't have leaflets coming off of a stem!
To determine the location of starch in a leaf, one can examine it under the microscope and apply one small drop of iodine to the leaf. The parts of the leaf that turn purple contain starch.
The leaf turns brittle during the testing the leaf for starch because the ethanol extracts the all water content from the leaf.