Take a healthy potted plant with elongated leaves. Select a leaf and insert about one half of this l

Question

Take a healthy potted plant with elongated leaves. Select a leaf and insert about one half of this leaf in a test tube containing KOH and make it air tight. Place the set-up in sun for two hours. Take out the leaf from the test tube and dip it in boiling water for a few minutes. Put this leaf in a beaker with alcohol and boil it in a water bath. Wash the leaf with water and then dip the leaf in iodine solution for a few minutes. The portion of the leaf dipped in KOH solution will not show any change when dipped in iodine solution.\ On the basis of this activity, we may conclude that the factor for photosynthesis is\

Professor PC Thomas Classes · Answer

(a) : The given experiment demonstrates the requirement of carbon dioxide for photosynthesis. When KOH absorbs the available $\mathrm{CO}_{2}$ from the portion of leaf dipped in it, formation of sugar and starch is inhibited and the portion of leaf dipped in KOH did not show any change when dipped in iodine solution. Thus, it is proved that $\mathrm{CO}_{2}$ is necessary for photosynthesis.\