OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What is the impact of a high water potential on plant health?

1. It generally leads to wilting and dehydration

2. It promotes a healthy and turgid state

3. It causes nutrient depletion in plants

4. It negatively affects photosynthesis

The correct answer is: It promotes a healthy and turgid state

A high water potential in plants indicates that there is a greater concentration of water outside the plant cells compared to the inside. This condition promotes the movement of water into the plant cells through osmosis, leading to an influx of water. As water enters the cells, it fills the vacuoles and applies pressure against the cell walls, resulting in turgidity. Turgid cells are essential for maintaining the structural integrity and rigidity of the plant, allowing it to stand upright and facilitating the optimal function of the leaves for photosynthesis. In this state, the cells are less likely to experience wilting, and the overall health of the plant is enhanced, contributing to effective nutrient transport and growth. Therefore, a high water potential supports the plant in adopting a healthy and robust form.