How do nutrient ions typically move to roots through transpiration?

How do nutrient ions typically move to roots through transpiration?

• A. Evaporation
• B. Mass flow
• C. Diffusion
• D. Concentration gradient

Answer: (B)

Nutrient ions move to roots through transpiration primarily via the process of mass flow. This mechanism is driven by the transpiration of water from plant leaves, which creates a negative pressure in the plant’s xylem, facilitating the upward movement of water (and dissolved nutrients) from the roots to the leaves. As water evaporates from the leaf surfaces, it helps pull more water from the soil through the roots, effectively carrying with it nutrient ions dissolved in that water. This movement is not based solely on the differences in concentration gradients or diffusion, which are more relevant for the movement of substances within a confined space or across membranes at a smaller scale, but mass flow combines the movement of water and nutrients together efficiently through the plant's vascular system.

Nutrient ions move to roots through transpiration primarily via the process of mass flow. This mechanism is driven by the transpiration of water from plant leaves, which creates a negative pressure in the plant’s xylem, facilitating the upward movement of water (and dissolved nutrients) from the roots to the leaves. As water evaporates from the leaf surfaces, it helps pull more water from the soil through the roots, effectively carrying with it nutrient ions dissolved in that water. This movement is not based solely on the differences in concentration gradients or diffusion, which are more relevant for the movement of substances within a confined space or across membranes at a smaller scale, but mass flow combines the movement of water and nutrients together efficiently through the plant's vascular system.