Plant-Derived Biostimulants and Liposomal Formulations in Sustainable Crop Protection and Stress Tolerance

Plant-derived biostimulants represent an innovative approach to enhancing crop productivity, resilience, and quality within sustainable agricultural systems by improving nutrient uptake, stress tolerance, and plant defense mechanisms while reducing reliance on synthetic inputs. However, their effectiveness is often limited by poor stability and low bioavailability. Recent advances in nanotechnology, particularly liposomal formulations, address these limitations by enhancing the stability, solubility, and delivery efficiency of bioactive plant compounds. Liposomes facilitate the penetration and systemic transport of active ingredients within plant tissues and enable controlled release at the target site, thereby increasing biostimulant efficacy. This review summarizes current knowledge on plant-derived biostimulants, their classification, nano-formulation, molecular mechanisms, and roles in mitigating abiotic and biotic stress. Special emphasis is placed on liposome-based formulations, including supercritical CO2 extracts and nano-liposomal delivery systems, with examples such as garlic extract and the EliceVakcina® complex. Finally, the potential of liposomal technologies in integrated crop protection and sustainable agriculture is discussed.