Rhizogenesis and caulogenesis are initiated by

Options

A. Auxin and Cytokinin
B. Auxin and Gibberellin
C. Gibberellin and cytokinin
D. Cytokinins and Zeatin

Answer

**Step-by-Step Solution:**

1. **Understanding Rhizogenesis and Caulogenesis:**
- Rhizogenesis refers to the formation of roots from plant tissues, specifically from callus tissue.
- Caulogenesis refers to the formation of shoots from plant tissues, also from callus tissue.

2. **Identifying the Hormones Involved:**
- The question asks which hormones initiate rhizogenesis and caulogenesis.
- The primary hormones involved in these processes are auxins and cytokinins.

3. **Analyzing the Options:**
- **Option A: Auxin and Cytokinin**
- Auxin promotes root formation (rhizogenesis).
- Cytokinin promotes shoot formation (caulogenesis).
- This option aligns with the definitions of rhizogenesis and caulogenesis.
- **Option B: Auxin and Gibberellin**
- While auxin promotes root formation, gibberellin is not primarily involved in root or shoot formation.
- **Option C: Gibberellin and Cytokinin**
- Gibberellin does not play a significant role in root formation, making this option incorrect.
- **Option D: Cytokinin and Zeatin**
- Zeatin is a type of cytokinin and does not contribute to root formation, thus this option is also incorrect.

4. **Conclusion:**
- The correct answer is **Option A: Auxin and Cytokinin** because auxin is responsible for rhizogenesis (root formation) and cytokinin is responsible for caulogenesis (shoot formation).

**Final Answer: Option A: Auxin and Cytokinin**

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