Question

Which of the following tissues originate from ray initials of cambium?

• A. Tracheids and vessels
• B. Sieve tubes and companion cells
• C. Xylem and phloem fibres
• D. Radial rows of parenchyma

Answer 1

Answer: (D)

Radial rows of parenchyma

Phloem is a complex tissue and is composed of four elements namely, sieve elements, companion cell, phloem fibres and phloem parenchyma.

Xylem is composed of tracheids, vessels, fibres and parenchyma. The primary xylem and phloem are derived from procambium, which is an embryonic tissue, while secondary xylem and secondary phloem are derived from vascular cambium, which is a lateral cambium. The ray initials of the vascular cambium divide tangentially and produce parenchymatous cells on both sides, which differentiate as parenchymatous vascular rays. These rays traverse from pith to cortex through secondary xylem and phloem. Thus, the correct answer is option D.