Efficient strategies for controlled release of nanoencapsulated phytohormones to improve plant stress tolerance

Abstract

Climate change due to diferent human activities is causing adverse environmental conditions and uncontrolled extreme weather events. These harsh conditions are directly afecting the crop areas, and consequently, their yield (both in quantity and quality) is often impaired. It is essential to seek new advanced technologies to allow plants to tolerate environmental stresses and maintain their normal growth and development. Treatments performed with exogenous phytohormones stand out because they mitigate the negative efects of stress and promote the growth rate of plants. However, the technical limitations in feld application, the putative side efects, and the difculty in determining the correct dose, limit their widespread use. Nanoencapsulated systems have attracted attention because they allow a controlled delivery of active compounds and for their protection with eco-friendly shell biomaterials. Encapsulation is in continuous evolution due to the development and improvement of new techniques economically afordable and environmentally friendly, as well as new biomaterials with high afnity to carry and coat bioactive compounds. Despite their potential as an efcient alternative to phytohormone treatments, encapsulation systems remain relatively unexplored to date. This review aims to emphasize the potential of phytohormone treatments as a means of enhancing plant stress tolerance, with a specifc focus on the benefts that can be gained through the improved exogenous application of these treatments using encapsulation techniques. Moreover, the main encapsulation techniques, shell materials and recent work on plants treated with encapsulated phytohormones have been compiled.