Question

When transpiration is rapid

• A. $\psi w$ of epidermal cells decreases
• B. a negative pressure develops in xylem vessel
• C. water is absorbed through the root passively
• D. all of these

Answer 1

The correct option is D all of these

Plants use water potential to transport water to the leaves so that photosynthesis can take place. Water potential ($\psi w$) is a measure of the potential energy in water where the difference between the potential in a given water sample and pure water measures. During transpiration, the evaporation of water from the surfaces of mesophyll cells to the atmosphere decreases $\psi w$ of the epidermal cells and also creates a negative pressure at the top of a plant. The resulting surface tension causes a negative pressure or tension in the xylem that pulls the water from the roots and soil. Then, the roots absorb water passively. As transpiration proceeds, water absorption occurs simultaneously to compensate the water loss from the leaf end.