Certified Crop Advisor Practice Exam

When a plant nutrient is absorbed with water that is moving to and into the plant root, the nutrient uptake process is called ________.

1. Active transport

2. Mass flow

3. Diffusion

4. Root interception

The correct answer is: Mass flow

The process described in the question refers to nutrient absorption that occurs alongside water movement into the plant roots. Mass flow is a key mechanism for this process, as it describes the movement of nutrients dissolved in water as it flows through the soil solution toward plant roots. When water uptake occurs through the roots, it carries along soluble nutrients, making them available for absorption by the plant. In contrast, active transport involves the movement of nutrients against their concentration gradient and requires energy. Diffusion is the passive movement of nutrients from areas of high concentration to low concentration and does not require bulk water movement. Root interception is a process where roots physically come into contact with nutrients in the soil rather than relying on the transport of nutrients through the soil solution. Thus, mass flow is the most accurate term for the scenario where nutrients are absorbed along with water moving into the plant roots.