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 Concept:
Plant anatomy differentiates between roots and stems of monocots and dicots based on the arrangement of vascular bundles (xylem and phloem).
Key Formula or Approach:
1. Roots: Always "Radial" (xylem and phloem on different radii).
2. Stems: Always "Conjoint" (xylem and phloem on the same radius).
3. Dicot: "Open" (contains cambium for secondary growth).
4. Monocot: "Closed" (no cambium).

Step 2: Detailed Explanation:
$\bullet$ P. Dicot root: Radial arrangement; typically diarch to tetrarch (2-4 xylem bundles). It is technically "open" in a developmental sense as secondary growth occurs later. $\rightarrow$ (i)
$\bullet$ Q. Dicot stem: Vascular bundles are arranged in a ring; they are conjoint, collateral, and open. $\rightarrow$ (ii)
$\bullet$ R. Monocot root: Radial arrangement; polyarch (more than 6 xylem bundles); no cambium (closed). $\rightarrow$ (iii)
$\bullet$ S. Monocot stem: Vascular bundles are scattered throughout the ground tissue; they are conjoint and closed. $\rightarrow$ (iv)

Step 3: Final Answer:
The matching is P-(i), Q-(ii), R-(iii), S-(iv).
This corresponds to option (A).