Question

The vascular bundle in a dicot stem is ____.

• A. Conjoint, collateral, closed
• B. Conjoint, collateral, open
• C. Radial, closed
• D. Radial, open

Hint:

Associate the word "Open" with an open door for growth. If cambium is present, the door is "open" for secondary growth (typical of dicot stems). If cambium is absent, it is "closed" (typical of monocot stems).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Vascular bundles are organized arrangements of xylem and phloem tissues. Their classification depends on their relative positions and the presence or absence of cambium tissue.

Step 2: Detailed Explanation:
In a dicot stem, the vascular bundles display specific structural features:
• Conjoint: Xylem and phloem are arranged along the same radius.
• Collateral: Phloem lies on the outer side and xylem lies on the inner side along that radius.
• Open: A strip of lateral meristem called intrafascicular cambium is present between the xylem and phloem. This cambium gives the bundle the capacity to form secondary xylem and phloem tissues (secondary growth).

Step 3: Final Answer:
The vascular bundle in a dicot stem is conjoint, collateral, open.