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)

The main idea is that water and mineral movement across plant membranes follows the same physical principles—osmosis for water and diffusion/active transport for ions. When fertilizer is sprayed on leaves, the high external solute concentration creates an osmotic gradient that pulls water out of leaf cells into the surrounding solution, leading to tissue dehydration and burn. Roots, on the other hand, absorb water and nutrients from the soil because the soil solution usually presents water potential that drives water into the roots, with minerals entering through root cell membranes via transport proteins and diffusion. The same mechanisms operate in both cases, just with the direction of movement reversed depending on where the gradient lies. So the statement is true.