The first natural cytokinin of plants is

Options

A. zeatin
B. kinetin
C. dihydrooxyzeatin
D. riboxylzeatin

Answer

### Step-by-Step Text Solution:

1. **Understanding the Question**: The question asks for the first natural cytokinin discovered in plants. Cytokinins are a class of plant hormones that promote cell division and growth.

2. **Definition of Cytokinins**: Cytokinins are plant growth substances that play a crucial role in cell division, particularly in the shoot and root regions of plants. They are involved in various plant processes, including growth, development, and aging.

3. **Identifying the Options**: The options provided are:
- A) GAT
- B) Kinetin
- C) Dihydroxygeatin
- D) Riboxylgeatin

4. **Researching the First Natural Cytokinin**: Among the options, we need to identify which one is recognized as the first natural cytokinin. Historical studies and research indicate that the first natural cytokinin to be discovered and purified from plant sources was GAT, which was extracted from maize kernels.

5. **Conclusion**: Based on the information gathered, the first natural cytokinin of plants is **GAT** (option A).

### Final Answer:
The first natural cytokinin of plants is **GAT** (Option A).

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