Which statement about leaf cuticle and herbicide absorption is true?

Which statement about leaf cuticle and herbicide absorption is true?

• A. A thick cuticle speeds absorption
• B. A thick cuticle slows absorption
• C. A cuticle has no effect
• D. A thin cuticle slows absorption

Answer: (B)

The leaf cuticle acts as a waxy protective barrier that controls how quickly substances can enter the leaf. A thicker cuticle means a longer, more resistant diffusion path, so foliar-applied herbicides penetrate more slowly. A thinner cuticle offers less resistance, allowing faster uptake. Therefore, the statement that a thick cuticle slows absorption best captures how cuticle thickness influences herbicide entry. The idea that a thick cuticle speeds absorption or that the cuticle has no effect contradicts how diffusion through a barrier works, and a thin cuticle slowing absorption is the opposite of what actually happens.

The leaf cuticle acts as a waxy protective barrier that controls how quickly substances can enter the leaf. A thicker cuticle means a longer, more resistant diffusion path, so foliar-applied herbicides penetrate more slowly. A thinner cuticle offers less resistance, allowing faster uptake. Therefore, the statement that a thick cuticle slows absorption best captures how cuticle thickness influences herbicide entry. The idea that a thick cuticle speeds absorption or that the cuticle has no effect contradicts how diffusion through a barrier works, and a thin cuticle slowing absorption is the opposite of what actually happens.