The Mechanisms of Plant Stress Mitigation by Kaolin-based Particle Films and Applications in Horticultural and Agricultural Crops

Abstract

Kaolin-based particle films have use in reducing insect, heat, photosynthetically active radiation (PAR), and ultraviolet radiation stress in plants resulting from the reflective nature of the particles. Particle films with a residue density of 1 to 4 g·m−2 have been evaluated in a range of crops and agricultural environments. The particle film is a general insect repellant resulting from the change in the plant’s leaf/fruit texture but also because it changes the reflected light signature of the plant causing insect avoidance for many pests. The alteration of reflected light is the result of the ability of the particle film to reflect infrared (IR), PAR, and ultraviolet radiation. Reflection of IR can reduce canopy temperature as much as 5 °C, which will reduce potential transpiration. The reduction of PAR by the film at the leaf level is compensated in varying degrees by diffusion of PAR into the interior of the canopy. Whole canopy photosynthesis can be increased by the combined particle film effects of reduced canopy temperature and increased diffusion of PAR into the interior of the canopy. In apple, reducing fruit surface temperature, PAR, and ultraviolet is an effective means of reducing sunburn damage. The use of a reflective particle film is effective in mitigating environmental stress and has significant economic benefits in agricultural crops.