Biostimulant Seed Priming Enhances Lettuce Seed Vigor, Storage Tolerance and Subsequent Plant Growth

Abstract

Seed priming with biostimulants has emerged as a promising strategy for enhancing seed vigor, storage tolerance, and plant establishment by modulating physiological and antioxidant mechanisms. Given the complexity of seed quality datasets, multivariate and machine learning approaches can improve data interpretation. Accordingly, this study evaluated the effects of biostimulant-mediated seed priming on lettuce seed vigour, storage tolerance, and subsequent plant growth using multivariate and machine-learning approaches. A completely randomized design with twelve replicates of 50 seeds was adopted. Biostimulants based on seaweed extracts and synthetic plant hormones were applied at concentrations of 0, 4, 8, 12, and 16 mL L⁻¹ using seed imbibition periods of 8 and 16 h. Untreated seeds were stored for 12 months under laboratory and refrigerated conditions and evaluated every three months; at each evaluation, seed samples were treated before physiological and biochemical analyses. Plant growth was evaluated under greenhouse conditions over four independent cultivation cycles. Seed imbibition for 8 h at 4 mL L⁻¹ consistently improved germination, seed vigour, and subsequent plant growth. The most effective treatments reduced malondialdehyde accumulation and increased catalase activity. Multivariate and machine learning analyses identified seedling length and germination speed index as the variables most strongly associated with seed vigour. Storage duration was the primary factor affecting seed quality, whereas refrigerated storage better preserved physiological performance. Overall, seed priming with biostimulants at 4 mL L⁻¹ for 8 h improved lettuce seeds physiological quality, maintained vigour during storage, and promoted superior plant growth under greenhouse conditions.