Question

steps of testing a leaf for starch​

Answer 1

Answer:

Put a few drops of iodine solution on the leaf if starch is present the brown hiding solution will turn blue black .

(Hopes this helps )

Answer 2

៚Starch Testing :

☆ Iodine solution is used to test leaves for the presence of starch. You need to:

• Heat a plant leaf in boiling water for 30 seconds (this stops its chemical reactions).

• Heat it in boiling ethanol for a few minutes (this removes most of its colour).

• Wash with water and spread onto a white tile.

• Add iodine solution from a dropping pipette.

➢ After a few minutes, the parts of the leaf that contain starch turn blue-black.

➢ Note that ethanol is heated using a hot water bath. Ethanol boils at 78°C, so a tube of it boils when placed in a beaker of hot water. This is safer than using a Bunsen burner because ethanol is flammable.

➢ Variegated leaves have green parts (where the cells contain chlorophyll) and white parts (where there is no chlorophyll). Only the parts that were green become blue-black with iodine solution, showing the importance of chlorophyll in photosynthesis.

➢ A plant can be ‘de-starched’ by leaving it in the dark for a few hours. Parts of its leaves are covered with dark paper, and the plant is left in the light for a few hours. Only the uncovered parts become blue-black with iodine solution, showing the importance of light in photosynthesis.

━━━━━━━━━━━━━━━━━━━━━━━━━━

@ɪтzкнυѕнɪ❤~