Question

The vascular cambial ring of a dicot stem is

• A. Primary in origin
• B. Secondary in origin
• C. Embryonic in origin
• D. Tertiary in origin
• E. Partly primary and partly secondary in origin

Answer 1

The correct option is E Partly primary and partly secondary in origin

Inter-fascicular cambium develops very early during the first year even before the beginning of secondary growth. The activity of the cambium increases their diameter and the vascular bundles become elongated in cross-section. More xylem than phloem elements is produced. Annual rings become clearly visible when vessels with a wide lumen are assembled first (early wood) than vessels with a narrow lumen (late wood).
Thus, the correct answer is option E.