Name the vital theory proposed by Sir J.C. Bose for ascent of sap.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Ascent of Sap**: The ascent of sap refers to the upward movement of water and minerals from the roots to the upper parts of the plant. This process primarily occurs through the xylem tissue.

2. **Role of Xylem**: Xylem is a complex tissue composed of both living and non-living cells. The non-living cells, specifically the conducting cells, are crucial for the ascent of sap. These cells have lignified walls that prevent water from leaking out.

3. **Theories of Ascent of Sap**: Various theories have been proposed to explain the mechanism of sap ascent. Among these, Sir J.C. Bose proposed a significant theory.

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