Question

Consider the following statements regarding the fate of a ring girdled plant and choose the most appropriate answer.

• A. Both the shoot and root of a ring girdled plant die together.
• B. The shoot of the plant dies first followed by the root.
• C. The root of the plant dies first followed by the shoot.
• D. Neither the root nor the shoot will die.

Answer 1

The correct option is C The root of the plant dies first followed by the shoot.

This experiment was concucted by Malpighi, Harting and Hales to identify tissues through which food is transported.

In this experiment, a ring of bark was cut up to the depth of phloem and removed. After a few weeks it was observed that the portion of the bark above the extracted ring was swollen.
This swelling was due to accumulation of sugar due to lack of downward movement of sugar in the absence of phloem.

It was observed that the removal of phloem had no effect on transpiration. Although the bark above the ring looked healthy the tissues below the ring stopped growing and began to shrivel. The roots eventually died first due to lack of sugar followed by the shoot. Thus concluding that phloem conducts food.