A carboxymethyl chitosan /trans-2-hexenal Schiff's base gel with controlled density using dynamic imine bonds:...

The volatile secondary metabolite trans-2-hexenal (T2H), an aldehyde, exhibits potent antibacterial properties. However, its high volatility presents challenges in sustaining prolonged efficacy in agricultural applications. In this study, carboxymethyl chitosan (CMCS) was utilized to immobilize T2H via Schiff's base reaction, resulting in the preparation of polysaccharide supramolecular hydrogels with self-triggered and tunable multifunctionality. These hydrogels exhibited rheological properties such as shear thinning, self-healing, and swelling behavior. By modulating the molar quantity of T2H, the density of the hydrogel could be adjusted accordingly. The dynamic imine bonds within the Schiff's base responded to acidic conditions induced by plant pathogenic microorganisms, facilitating pH-controlled release of T2H. Moreover, the CMCS-T2H hydrogels exhibited resistance against photolysis and rain erosion while demonstrating prolonged control effects against pathogens such as P. capsici and F. graminearum. Additionally, these hydrogels not only possessed bactericidal activity but also promoted the growth of wheat seed root buds and reduced vomiting toxin content in seeds without compromising biosafety for target plants. These findings will provide valuable insights into the effective utilization of volatile aldehyde secondary metabolites and a sustainable approach to managing plant diseases.