Synergistic Effects of Far-Infrared Radiation and Static Magnetic Fields as Physical Biostimulants on In Vitro Germination of Jalapeño Pepper

Among the options to improve the establishment of jalapeno pepper (Capsicum annuum L.), physical biostimulants such as far-infrared bioceramics (FIR) and static magnetic fields (MF) have emerged as non-chemical alternatives. This study evaluated, under in vitro conditions, the individual and combined effects of FIR and positive or negative MF on seed germination dynamics, early seedling morphology, water status, and photosynthetic pigments. A completely randomized design with eight treatments was implemented, including FIR applied continuously throughout the entire experimental period, positive or negative MF applied for 24 h (MF+24, MF−24), and FIR + MF combinations under continuous or 24 h exposure regimes (n = 7). Germination percentage, mean germination time (MGT), mean germination rate (MGR), germination index (GI), morphological variables, water content (WC), and photosynthetic pigments were measured; ANOVA/alternative tests (a = 0.05), Principal Components Analysis (PCA) and exploratory Spearman’s correlations were used to assess relationships among the evaluated variables. Germination percentage did not change (97.64%), but kinetics did: FIR + MF−24 reduced MGT to 4.32 d, FIR increased MGR to 5.83 seeds day−1 (+11.69%), and FIR24 + MF+24 showed the highest GI (4.57). For morphological, MF+24 increased hypocotyl length (+16.29%), FIR increased collar diameter (+27.27%), and FIR + MF−24 increased cotyledon area (25%), and FIR increased chlorophyll a (+139%), chlorophyll b (+141%), and carotenoids (+114%). PCA explained 66.9% of the variance, grouping FIR with growth variables and FIR + MF combinations with WC and pigments. Inferences are limited to one cultivar and controlled in vitro conditions. This study provides novel quantitative evidence that continuous and short-term applications of FIR and MF modulate germination dynamics and early physiological traits without altering final germination, related to structure and pigments, without changing final germination percentage.