Question

Central vascular cylinder or stele consists of the primary vascular system (xylem and phloem) and the associated fundamental tissue. Match the schematics of stele in Group I (xylem shown in green, and phloem shown as with their respective types in Group II. \includegraphics[width=0.75\linewidth]{image58.png}

• A. P-2; Q-4; R-1; S-3
• B. P-5; Q-1; R-4; S-2
• C. P-5; Q-3; R-1; S-2
• D. P-3; Q-4; R-2; S-5

Hint:

Remember: Protostele = solid core, Eustele = ring, Atactostele = scattered, Siphonostele = hollow with phloem. Ectophloic has phloem outside only, Amphiphloic has phloem on both sides.

Answer 1

The Correct Option is A

Step 1: Identify each stele type
- Protostele (1): The most primitive stele with a solid core of xylem surrounded by phloem. Common in roots of vascular plants and lower pteridophytes.
- Eustele (2): Vascular bundles are arranged in a ring, typical of dicot stems.
- Atactostele (3): Vascular bundles scattered throughout ground tissue, typical of monocot stems.
- Ectophloic siphonostele (4): A hollow cylinder of xylem surrounded externally by phloem.
- Amphiphloic siphonostele (5): Xylem ring is surrounded by phloem on both outer and inner sides.
Step 2: Match with Group I diagrams
- (P) Ring-like vascular bundles $⇒$ Eustele (2).
- (Q) Concentric siphonostele with phloem outside only $⇒$ Ectophloic siphonostele (4).
- (R) Solid central xylem surrounded by phloem $⇒$ Protostele (1).
- (S) Scattered vascular bundles $⇒$ Atactostele (3).
Therefore, the correct matching is: P-2; Q-4; R-1; S-3.