A Ganong’s Potometer is an apparatus used to measure the amount of moisture absorption by a leafy shoot during transpiration. It’s also referred to as a transpirometer. Let’s delve into its design and purpose:

1. Design and Components:

   • The Ganong’s Potometer consists of the following parts:
     • Broad-Mouthed Glass Cylinder: Located at the front end of the setup, it has an opening attached to a single-holed cork (usually made of rubber). The newly cut twig for the experiment is placed through this hole.
     • Horizontal Glass Rod: This long glass tube contains a capillary tube placed within it. The capillary tube has graduated markings for measuring water movement.
     • Nozzle Mouth: The bent end of the horizontal rod, which is placed in a beaker containing colored liquid (usually water).
     • Reservoir: A vertically placed reservoir connected to the horizontal rod. Water accumulates in the reservoir.
     • Pinch Cock or Stop Cock: Located at the bottom of the reservoir, it controls the flow of water from the reservoir to the horizontal rod.
     • Plastic Stand: The entire apparatus is mounted on a flat surface, such as a table, using a stand.

2. Working Principle:

   • A bubble is forced into the capillary tube.
   • As the plant absorbs water through transpiration and photosynthesis, the bubble starts moving.
   • By observing regular markings on the capillary tube, we can calculate the amount of water absorbed.

3. Purpose:

   • The Ganong’s Potometer is primarily used to measure the transpiration rate in a cut twig under controlled laboratory conditions.
   • It helps us understand how much water a plant absorbs during transpiration.