Describe ringing experiment with diagram.

Explanation

The experiment involves the removal of all the tissue outside to vascular cambium ( bark, cortex, and phloem) in woody stems except xylem. Xylem is the only remaining tissue in the girdled area which connects upper and lower part of the plant. This setup is placed in a beaker of water. After some time, it is observed that a swelling on the upper part of the ring appears as a result of the accumulation of food material. If the experiment continues within days, the roots die first. It is because, the supply of food material to the root is cut down by roots gradually die the upper part ( stem), which depends on root for the ascent of sap, will ultimately die.