Find out one w.r.t. differentiation
(a) Loss of nucleus in sieve
(b) Death of protoplasm in tracheary elements
(c) Callus formation
(d) Lignification in vessels

Options

A. Loss of nucleus in seive
B. Death of protoplasm in tracheary elements
C. Callus formation
D. Lignification in vessels

Answer

To solve the question regarding differentiation in plant cells, we need to analyze the options provided and identify which one is specifically related to the process of differentiation.

### Step-by-Step Solution:

1. **Understanding Differentiation**: Differentiation in plants refers to the process by which unspecialized cells develop into specialized cells with distinct structures and functions. This often involves changes in cell structure, loss of certain components, and the development of specific characteristics.

2. **Analyzing Each Option**:
- **(a) Loss of nucleus in sieve elements**: Sieve elements are part of the phloem and lose their nucleus during differentiation. This is a part of their maturation process but does not involve the death of the cell.
- **(b) Death of protoplasm in tracheary elements**: Tracheary elements (like tracheids and vessel elements) undergo differentiation where they lose their protoplasm and become dead cells at maturity. This is a key characteristic of their differentiation process.
- **(c) Callus formation**: Callus formation is a process of tissue regeneration and does not directly relate to differentiation of specific cell types.
- **(d) Lignification in vessels**: Lignification refers to the deposition of lignin in cell walls, which is a part of the maturation of certain cells but does not directly indicate differentiation.

3. **Identifying the Correct Answer**: Among the options, the death of protoplasm in tracheary elements (option B) is the most relevant to differentiation. This process signifies that the cells have completed their differentiation and are now specialized for their function in water conduction.

### Final Answer:
**(b) Death of protoplasm in tracheary elements**

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