Optimizing the size of mesoporous silica nano-delivery system enhances the absorption, transport, and retention of pesticides in tea plants

Abstract

Enhancing the absorption, transportation, and persistence of pesticides in tea plants can achieve long-term effective management of piercing-sucking pests in tea gardens. Nano-delivery systems exhibit significant potential in achieving these objectives, yet our understanding of how nano-delivery system sizes influence these processes remains limited. Herein, we synthesized mesoporous silica nano-delivery systems with mean diameters of 27, 54, and 114 nm to encapsulate acetamiprid and investigated their uptake, translocation, and distribution following foliar application in tea plants. Among these, the 54 nm nano-delivery system exhibited superior absorption and transport capacity, allowing it to enter cells, whereas nano-delivery systems of other sizes demonstrated limited cellular uptake. As a result, only the 54 nm nano-delivery system effectively penetrated vascular tissue via the symplastic pathway, reaching the stem and predominantly accumulating in the xylem. Interestingly, nano-delivery systems within the vascular tissue retained the capacity to release acetamiprid, potentially facilitating continuous absorption and transport of acetamiprid within the tea plants. This feature is crucial for combating piercing-sucking pests that feed on plant sap by piercing the host plant's vascular tissue. These findings pave the way for designing nano-delivery systems with optimal particle sizes to enhance pesticide absorption, transportation, and persistence, thus achieving long-term control of piercing-sucking pests and increasing yields of tea plants.