While not classified as essential, iodine can be a beneficial element, helping to modulate redox balance and enhance stress tolerance. We assessed whether seed treatment with iodine nanocitrate affects PSII photochemical parameters (F0, Fv/Fm), pigment composition, and wheat yield under pathogen inoculation in field conditions, while monitoring ambient air quality and short-term temperature variability. The experimental design included the following factors: (i) cultivars (Zelma, Zymoyarka); (ii) seed priming (control, iodine nanocitrates (I-0.5%)); and (iii) infection background (uninoculated, phytoplasma-like pathogen ( Acholeplasma laidlawii ), bacterial pathogen Pseudomonas syringae pv. atrofaciens (Psa). F 0 and Fv/Fm were measured at 7-day intervals. Treatment effects were tested within cultivar × date using a one-way ANOVA with Tukey's HSD; factorial effects of date, cultivar, and variant were assessed using ANOVA models. Seed priming with I-0.5% showed strong temporal and cultivar dependence in Fv/Fm, with significant date-related shifts and cultivar- and variant-dependent patterns. Variant separation was clearer in Zymoyarka, while Zelma showed generally lower intradate divergence. Pigment composition revealed contrasting cultivars' strategies: Zymoyarka exhibited pigment depletion, most strongly at I-0.5%+Psa, whereas Zelma typically increased chlorophyll and carotenoid content after inoculation and priming. Flag leaf area was consistently larger in Zelma and was mainly genotype-driven. Grain yield increased at I-0.5% in both cultivars, reaching statistical significance in Zymoyarka. Iodine nanocitrate priming can alter PSII functional status and pigment balance in a cultivar-specific manner under pathogen inoculation in the context of monitored ambient air pollution quality. Agronomic benefits (yield) were most pronounced in Zymoyarka, which also showed stronger within-date Fv/Fm divergence among variants and a depletion/remodeling-type pigment response (most evident under I-0.5% + Psa), consistent with greater physiological sensitivity/plasticity of this cultivar under the prevailing field load. • Iodine nanocitrate priming modulated PSII efficiency in a cultivar-specific manner. • Fv/Fm was more informative than F 0 under combined stress • Fv/Fm responses depended on sampling date and infection background. • Genetically distinct cultivars showed contrasting adaptation strategies: pigment depletion (stress-linked remodeling) or pigment stabilization/accumulation. • Grain yield increased at seed priming with nanoiodine, significantly in Zymoyarka under a field stress background. • Iodine nanopriming can be beneficial under field multi-stressor regimes
Huliaieva et al. (Fri,) studied this question.