Question

Which of the following is absent in monocot stem? ____.

• A. Phloem
• B. Cambium
• C. Xylem
• D. Pith

Hint:

Remember: - Dicot stem = Open bundles = Cambium Present $\rightarrow$ Can form wood. - Monocot stem = Closed bundles = Cambium Absent $\rightarrow$ Cannot form wood.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Stem anatomy varies widely across seed plants, with monocotyledonous structures lacking specific lateral meristematic tissue required for secondary widening.

Step 2: Detailed Explanation:
In a monocot stem, the vascular bundles are conjoint, collateral, and closed. They are described as closed because they entirely lack cambium tissue between the xylem and phloem. Because this lateral meristemic cambium strip is absent, monocot stems are incapable of undergoing normal secondary growth (thickening), which keeps their stems uniformly slender over their lifespan (e.g., in Grass, Maize, Bamboo). Monocot stems also lack a distinct central pith, as the vascular bundles are scattered throughout the ground tissue, making cambium the primary anatomical layer absent from the vascular system.

Step 3: Final Answer:
Cambium is absent in the vascular bundles of a monocot stem.