Question

Variegated leaf is plucked from Coleus plant kept in sunlight. It is de-starched by keeping in dark room for 24 hours. The picture of this leaf is draw n and the patches of cholorphyll on the leaf are marked. After immersing the leaf in boiling water follow ed by alcohol it is tested for starch using iodine solution. Record your observation.

Answer 1

Experiment to show that Chlorophyll is essential for photosynthesis:

Aim: To show that chlorophyll is essential for photosynthesis We need Coleus (croton) plant with variegated leaves, boiling water, alcohol and iodine solution.

Take coleus (croton) plant with variegated leaves. Destarch the leaves of the plant, by keeping the plant in dark room for 24 hours. Then keep the plant in the sunlight for four to six hours for photosynthesis. Pluck a leaf and draw the picture of the leaf. Mark the patches of chlorophyll on the leaf. After immersing the leaf in boiling water and then in alcohol, it is tested for starch with iodine solution. The patches of the leaf with chlorophyll turn blue – black. The other portions remain colourless. This experiment shows that chlorophyll is essential for photosynthesis.