Question

Answer the following question.

A student was observing a slide with no label under a microscope. The section had some vascular bundles scattered in the ground tissue. It is a section of a monocot stem! He exclaimed. No! it is a section of fern rachis, said the teacher. Teacher told to observe vascular bundle again. Student agreed, Why?

Answer 1

1. In fern rachis, the number of vascular bundles is less as compared to the number of vascular bundles in monocot stem. In monocot stem, vascular bundles are numerous.
2. In fern rachis, xylem consists of only tracheids whereas in monocot stem, xylem consists of vessels (protoxylem and metaxylem) as well as tracheids. Monocot stem shows the presence of lysigenous cavity just below protoxylem.
3. In fern rachis, phloem consists of only sieve cells whereas in monocot stem, phloem consists of sieve tubes and companion cells.
   Thus, a student must have observed these differences in the given section and agreed to teacher’s statement that the given section is of fern rachis and not of monocot stem.