What is the source of explant in meristem culture? Mention one function of cytokinins used in meristem culture medium.

Explanation

### Step-by-Step Solution:

1. **Understanding Meristem Culture**:
- Meristem culture involves the use of meristematic tissue, which is a type of plant tissue that is actively dividing and responsible for growth.

2. **Identifying the Source of Explant**:
- The explant in meristem culture is derived from the **apical meristem** or **apical bud** of the plant. This is the region where the cells are rapidly dividing, making it an ideal source for tissue culture.

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