Which of the following is enucleate at maturity?

Options

A. Palisade cell
B. Companion cell
C. Cortical cell
D. Sieve tube element

Answer

To determine which of the following is enucleate at maturity, we need to analyze the options provided:

1. **Sieve Cell**
2. **Companion Cell**
3. **Cortical Cell**
4. **Sieve Tube Elements**

### Step-by-Step Solution:

1. **Understanding Enucleate Cells**:
- Enucleate cells are those that do not have a nucleus at maturity. This is an important characteristic for certain types of cells in plants.

2. **Analyzing Each Option**:
- **Sieve Cell**: These are involved in the transport of nutrients in plants, but they typically contain a nucleus.
- **Companion Cell**: These cells are closely associated with sieve tube elements and do contain a nucleus, playing a role in the functioning of sieve tubes.
- **Cortical Cell**: These cells are found in the cortex of roots and stems and typically have a nucleus.
- **Sieve Tube Elements**: These are specialized cells in the phloem that transport sugars and nutrients. At maturity, they lose their nucleus, ribosomes, and vacuoles, making them enucleate.

3. **Conclusion**:
- Among the options, **Sieve Tube Elements** are the only cells that are enucleate at maturity. Therefore, the correct answer is **Sieve Tube Elements**.

### Final Answer:
**Sieve Tube Elements** are enucleate at maturity.

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