The chemical process by which fertilizer burn occurs on the leaves and water and nutrients are absorbed by the roots is the same, albeit in a reverse direction.

The chemical process by which fertilizer burn occurs on the leaves and water and nutrients are absorbed by the roots is the same, albeit in a reverse direction.

• A. Not related
• B. Unclear
• C. True
• D. False

Answer: (C)

This item tests how water potential and osmosis drive movement of water and nutrients in plants. Fertilizer salts on leaf surfaces raise the local solute concentration, lowering the water potential there. Because water moves from higher to lower water potential, water leaves the leaf cells toward the salt-rich surface, causing desiccation and visible burn. In contrast, when roots take up water and nutrients, water moves from the soil into the root cells along favorable gradients, with ions entering through membrane transport proteins and sometimes using energy to push against gradients. The same chemical principle—movement driven by differences in solute concentration and water potential—controls both processes; the direction is simply reversed between leaves (water moves out of cells) and roots (water and nutrients move into cells).

This item tests how water potential and osmosis drive movement of water and nutrients in plants. Fertilizer salts on leaf surfaces raise the local solute concentration, lowering the water potential there. Because water moves from higher to lower water potential, water leaves the leaf cells toward the salt-rich surface, causing desiccation and visible burn. In contrast, when roots take up water and nutrients, water moves from the soil into the root cells along favorable gradients, with ions entering through membrane transport proteins and sometimes using energy to push against gradients. The same chemical principle—movement driven by differences in solute concentration and water potential—controls both processes; the direction is simply reversed between leaves (water moves out of cells) and roots (water and nutrients move into cells).