Question

Removal of a ring of bark from the trunk of a tree eventually kills it, because

• A. Water can not go up
• B. Fungi and insects attack exposed parts
• C. Food does not travel down and root becomes starved
• D. Air blocks the xylem

Answer 1

The correct option is C Food does not travel down and root becomes starved

In plants sugars are translocated by phloem tissue. This can be experimentally demonstrated by girdling experiments. In girdling experiments all tissues from phloem to epidermis, including secondary phloem are removed. This stops flow of sugars to plant parts below the level of girdle. Thus, the roots are starved and consequently the plant is killed.