Tyloses are observed in the lumen of

Options

A. Thylakoids
B. Sieve tubes
C. Sap wood
D. Heart wood

Answer

**Step-by-Step Solution:**

1. **Understanding Tyloses**: Tyloses are balloon-like outgrowths that occur from the parenchyma cells into the lumen of tracheids or vessels in the secondary xylem.

2. **Historical Context**: The term "tyloses" was first introduced by Malpighi in 1686, who observed these structures in the vessels of heartwood.

3. **Location of Tyloses**: Tyloses are specifically found in the lumen of vessels in heartwood. Heartwood is the central, non-living part of a tree that provides structural support.

4. **Conclusion**: Based on the definition and historical context, the correct answer to the question "Tyloses are observed in the lumen of" is heartwood.

5. **Final Answer**: Therefore, the answer is option D: heartwood.

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