Stomatal penetration cannot occur unless the surface tension of the spray is reduced by wetting agents.

Stomatal penetration cannot occur unless the surface tension of the spray is reduced by wetting agents.

• A. False.
• B. True.
• C. Only for fruit crops.
• D. Only when temperatures exceed 30°C.

Answer: (B)

The key idea here is how a spray actually gets into the leaf through stomata. Stomatal penetration relies on the spray properly wetting the leaf surface so droplets can reach and enter the stomatal openings. Wetting agents reduce surface tension, which helps the spray spread across the leaf and penetrate into those tiny pores rather than bead up on the surface. If surface tension isn’t reduced, droplets tend to stay as beads on the surface and penetration through stomata is greatly limited, making effective entry unlikely. That’s why the statement is true: reducing surface tension with a wetting agent is typically needed for stomatal penetration. This isn’t about a specific crop or a particular temperature—the mechanism applies broadly, so the other options don’t fit.

The key idea here is how a spray actually gets into the leaf through stomata. Stomatal penetration relies on the spray properly wetting the leaf surface so droplets can reach and enter the stomatal openings. Wetting agents reduce surface tension, which helps the spray spread across the leaf and penetrate into those tiny pores rather than bead up on the surface. If surface tension isn’t reduced, droplets tend to stay as beads on the surface and penetration through stomata is greatly limited, making effective entry unlikely. That’s why the statement is true: reducing surface tension with a wetting agent is typically needed for stomatal penetration. This isn’t about a specific crop or a particular temperature—the mechanism applies broadly, so the other options don’t fit.