What are adjuvants that help a liquid enter a leaf called?

The term that describes adjuvants designed to enhance the absorption of a liquid into a leaf is "penetrants." These substances improve the ability of liquid applications, such as herbicides or pesticides, to be absorbed by the plant tissue.

When a liquid is sprayed onto plant surfaces, it can sit on the leaf's cuticle, which serves as a barrier to prevent excessive water loss but can also hinder the uptake of certain chemicals. Penetrants work by altering the surface properties of the leaf, facilitating the movement of the liquid through the cuticle and into the leaves. This can significantly increase the effectiveness of the treatment by ensuring that the active ingredients come into contact with the plant tissue where they can exert their effects.

While surfactants are often used to enhance spread and reduce surface tension, and emulsifiers help mix oil and water in a formulation, their primary functions differ from the specific role of penetrants. Thickeners modify the viscosity of the product but do not contribute to the absorption process through plant surfaces. This understanding highlights why penetrants are the right choice for improving liquid absorption into leaves.