Root pressure develops due to

Options

A. active absorption
B. low osmotic potential in soil
C. passive absorption
D. increase in transpiration

Answer

**Step-by-Step Solution:**

1. **Understanding Root Structure**: The root consists of various cells, including root hair cells, which are crucial for water absorption. The root xylem transports water upwards from the roots to the rest of the plant.

2. **Soil Composition**: The soil surrounding the roots often contains a higher concentration of salts compared to the inside of the root hair cells. This difference in concentration is essential for the process of water absorption.

3. **Active Absorption of Salts**: The root hair cells actively absorb salts from the soil. This process is known as active transport, which requires energy (ATP) because it moves substances against their concentration gradient (from low concentration in the soil to high concentration inside the root hair cells).

4. **Hypertonic Condition**: As salts accumulate inside the root hair cells, the concentration of solutes increases, making the inside of the cell hypertonic compared to the surrounding soil. This results in a decrease in water potential within the root hair cells.

5. **Water Movement**: Due to the decrease in water potential inside the root hair cells, water from the soil moves into the root hair cells through osmosis. This movement continues as water flows from the root hair cells to neighboring cells, creating a continuous inflow of water.

6. **Formation of Root Pressure**: The continuous inflow of water into the root hair cells and subsequently into the xylem creates pressure within the root system. This pressure is known as root pressure, which helps in pushing water upwards through the plant.

7. **Conclusion**: Therefore, root pressure develops primarily due to the active absorption of salts from the soil, which leads to a decrease in water potential and results in the movement of water into the roots.

**Final Answer**: Root pressure develops due to the active absorption of salts from the soil.

---