Question

Which one of the following choices matches the organs in column I with their vascular system arrangement described in column II?

• A. P - (i); Q - (ii); R - (iii); S - (iv)
• B. P - (ii); Q - (i); R - (iv); S - (iii)
• C. P - (iii); Q - (iv); R - (i); S - (ii)
• D. P - (iv); Q - (iii); R - (ii); S - (i)

Hint:

A quick shortcut for vascular bundles:
Root = Radial (R with R)
Stem = Conjoint
Dicot = Open (capable of secondary growth)
Monocot = Closed
Monocot root has Polyarch xylem (Poly = many).

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question requires matching different plant organs (roots and stems of monocots and dicots) with their characteristic anatomical arrangements of vascular tissues (xylem and phloem).

Step 2: Key Formula or Approach:
To solve matching questions in plant anatomy, recall key classification criteria:
1. Roots always have a "radial" vascular arrangement where xylem and phloem are on different radii.
2. Stems always have a "conjoint" arrangement where xylem and phloem are on the same radius.
3. "Open" vascular bundles contain cambium (allowing secondary growth, characteristic of dicots).
4. "Closed" vascular bundles lack cambium (characteristic of monocots).

Step 3: Detailed Explanation:
Let's analyze each organ systematically:

• P. Dicot root:
- Roots have radial vascular bundles.
- They are typically diarch to tetrarch (containing 2 to 4 xylem/phloem groups).
- While primary root vascular bundles are technically closed initially, they are termed "open" in a developmental sense because a secondary cambium ring forms later to initiate secondary growth.
- Thus, P matches with (i) (Radial, open, diarch to tetrarch).

• Q. Dicot stem:
- Dicot stems are characterized by vascular bundles arranged in a distinct ring.
- The bundles are conjoint (xylem and phloem together on the same radius), collateral, and open (possessing intrafascicular cambium).
- Thus, Q matches with (ii) (Ring, conjoint, open).

• R. Monocot root:
- Monocot roots have radial vascular bundles.
- They contain many vascular bundles, typically more than six, which is termed polyarch.
- They lack cambium completely, making them closed.
- Thus, R matches with (iii) (Radial, closed, polyarch).

• S. Monocot stem:
- Monocot stems have numerous vascular bundles scattered throughout the ground tissue.
- The bundles are conjoint and closed (no cambium present).
- Thus, S matches with (iv) (Scattered, conjoint, closed).

Step 4: Final Answer:
Matching these up: P - (i), Q - (ii), R - (iii), S - (iv). This corresponds perfectly to option (A).