Seedling priming with UV-A radiation induces positive responses in tomato and bell pepper plants under water stress

Stimulating crops to cope with various stressful conditions is an increasingly interesting strategy, even more so when this process is done through seed or seedling priming, since it is simpler and cheaper. The use of UV -A radiation for this purpose can be a viable, economical and environmentally friendly alternative. That is why the aim of this study was to evaluate if seedling priming with UV -A radiation is capable to help tomato and bell pepper plants tolerate water stress. For this, an experiment was carried out in both crop plants, where UV -A radiation was applied directly on the seedlings prior to transplanting on a single occasion, and for two hours. The crops were developed both in optimal water conditions and under water stress conditions. The results obtained show that priming with UV -A decreased the negative effects of water stress in tomato, increased fruit yield by 24.5% and root dry biomass by 46% compared to the stressed control. UV -A priming increased the proline content 294% when there was no stress, and 164% under water stress. Moreover, phenolic compounds were increased by UV -A priming under water stress. In bell pepper, priming with UV -A increased root dry biomass 26% compared to stressed control, but there were no differences in fruit yield. UV -A priming increased 68% more MDA when there was no stress, while under water stress increased 34%. In addition, UV -A priming increased chlorophyll content under water stress. Seedling priming with UV -A radiation can be an efficient strategy to induce tolerance to water stress in agricultural crops, with the great advantage that it is an easy -to -apply and environmentally friendly technology.