Question

Meaningful girdling (ringing) experiment cannot be done on sugarcane because

• A. Phloem is present inside the xylem.
• B. It can not tolerate the injury.
• C. Vascular bundles are scattered.
• D. Plants are very delicate.

Answer 1

The correct option is C Vascular bundles are scattered.

• Monocots have scattered vascular bundles, while dicots have a continuous ring arrangement of vascular bundles. In a dicot stem, after a few years of growth, phloem is present as a single continuous layer or sheet on the outer side as a constituent of bark.
• It can be easily removed because it is present as a continuous sheet. In a similar manner phloem cannot be removed in a monocot stem, because of the scattered arrangement, some of the vascular bundles might be present near the surface and some embedded deep inside.
• Removing phloem from each of the bundles individually is not possible. The girdling experiment is used to identify the tissue through which food is conducted. In this experiment, a ring of phloem is removed from the woody plant.
• Hence girdling experiments cannot be performed on a monocot stem-like sugarcane.