Question

According to 'histogen theory', during apical organization three histogens are formed. The part differentiated by plerome is

• A. Cortex
• B. Xylem and phloem
• C. Ground tissue system
• D. Stele

Answer 1

The correct option is B Xylem and phloem

Meristematic tissue is at a constant state of division and they are generally found at the growing tip of root and stem. According to histogen theory proposed by Hanstein, shoot apical meristem consists of three distinct zones.

i) Dermatogen (external layer), which form the outer covering of all organ of the plant. ii) Periblem (middle layer) gives rise to cortex and endodermis.

iii) Plerome (central layer) form pith and primary vascular bundle. Thus, plerome is present in between xylem and phloem.

So, the correct answer is option B.