Question

A variegated leaf is put in between two pieces of cork inserted in the mouth of a bottle containing small amount of KOH .The leaf is fixed in such a way that some part of it is inside the bottle; some in between the piece of cork & rest outside. The petiole of leaf is dipped in water. The whole examination is under proper temperature & light.

What is the name and purpose of this experiment?

• A. Kreb's experiment showing respiration
• B. Moll's experiment showing photosynthesis
• C. Sach's experiment showing ascent of sap
• D. A photometer showing transpiration

Answer 1

The correct option is B

Moll's experiment showing photosynthesis

The correct option is option (B):

Explanation for correct option:

1. The aim of Moll’s experiment is to demonstrate the importance of CO₂ in photosynthesis.
2. In this experiment a variegated leaf is fixed between two corks of a bottle in such a way that some part of the leaf is inside the bottle and some part is outside of the bottle.
3. The bottle contains some amount of KOH.
4. Keep this experimental set up in light for some time.
5. After some time, take the leaf from the bottle and boil it in alcohol and then add some iodine solution to it.
6. The part of the leaf which is kept inside the bottle did not turn blue.
7. It indicates that the part of the leaf which is inside the bottle lacks starch i.e., it did not perform photosynthesis.
8. It is because KOH which is present in the bottle will absorb CO₂ and hence it cannot perform photosynthesis.

Explanation for incorrect options:

Option (A):

1. Aim of Krebs experiment is to demonstrate that CO₂ is released during respiration.

Option (C):

1. In Sach’s experiment it is proved that water is imbibed through the cell wall and not through the lumen.

Option (D):

1. A Photometer is used to determine the rate of transpiration.

Final answer: Moll’s experiment shows the importance of CO₂ in photosynthesis.