Chitooligosaccharide modified pesticide-loaded polyurethane microcapsules to mitigate drought stress in wheat

To cope with global climate change and ensure food security, the development of functional pesticide carriers suitable for application on plants under drought stress is an important research direction. Herein, polyurethane microcapsules loading prothioconazole (PUMC@PRO) were synthesized using interfacial polymerization. Subsequently, chitooligosaccharide (COS) and glutaraldehyde (GA) were incorporated to prepare microcapsules with cross-linked network containing Schiff bases (PUMC-COS@PRO). Results demonstrated that the fitting degree of the release curve of PUMC-COS@PRO to the zero-order release kinetic model can reach up to 0.99. Due to the synergistic effect of the microcapsule shell and cross-linked network structure containing Schiff base (C=N), the half-life of PUMC-COS@PRO is 6.6 h in UV, which is approximately 28 times that of commercial microemulsion. After the introduction of COS with biologically activity, the EC50 can decrease significantly to as low as 1.612 μg/mL. In the growth promotion test, the PUMC-COS@PRO suspension exhibited the most growth promotion rate of 16.74 % on wheat stem length. Under simulated drought stress conditions, the growth promotion rates of the PUMC-COS@PRO suspension for wheat coleoptiles and radicles can achieve 22.46 % and 59.77 %, respectively. Therefore, this study provided a promising functionalized pesticide carrier for crops under drought stress in agricultural production.