Question

How many histogen are present in a monocot root apex?

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is D 4

• According to histogen theory, as proposed by Hanstein, the root and shoot apices have three distinct meristematic regions called histogens, these are namely dermatogens, periblem, and plerome.
• The dermatogens make uniseriate epidermis by anticlinal divisions, periblem forms cortex and plerome serve as a progenitor of stele (pericycle, vascular bundles, pith rays or medullary rays and pith).
• Monocotyledons have four histogens; calyptrogen being the fourth one that makes root cap.

Thus, the correct answer is option D.