Root Hair and Water Absorption

Root hair is a tubular extension of epidermal cells in the roots of plants. It is responsible for absorbing water and minerals from the soil. The following are the ways by which water is absorbed by the root hair:

Osmosis and Water Potential

Water potential (Ψ) is the measure of the tendency of water to move from one place to another. Water moves from an area of high water potential to an area of low water potential. The water potential of the soil solution is lower than the water potential of the root hair cell. Hence, water moves from the soil solution to the root hair cell by osmosis.

Water Potential Gradient

The water potential gradient is the difference in water potential between two points. The water potential of the soil solution is lower than the water potential of the root hair cell. Hence, there is a water potential gradient from the soil solution to the root hair cell. This causes water to move into the root hair cell.

Osmotic Pressure

Osmotic pressure is the pressure that must be applied to a solution to prevent the inward flow of water. The root hair cell has a higher solute concentration than the soil solution. Hence, the osmotic pressure of the root hair cell is higher than the osmotic pressure of the soil solution. This causes water to move into the root hair cell.

Conclusion

In conclusion, water enters the root hair cell due to osmotic pressure. The root hair cell has a higher solute concentration than the soil solution. Hence, the osmotic pressure of the root hair cell is higher than the osmotic pressure of the soil solution. This causes water to move into the root hair cell.