Priming effect with selenium and iodine on broccoli seedlings: Activation of biochemical mechanisms to mitigate cold...

This study aimed to improve broccoli seedlings' cold stress tolerance by priming them with selenium (Se) and iodine (I). Different doses of selenium (0, 25, 50, and 75 mg L^-1) and iodine (0, 50, 100, 250, and 500 mg L^-1) were applied individually and in combination, totaling 21 treatments. After foliar spraying of Se and I, the seedlings were exposed to 20/2 °C (day/night) for three days. Antioxidant enzyme activities and osmoprotectant contents were then analyzed. Se75, Se75+I50, and I100 treatments significantly reduced leaf damage (2.64 %, 3.11 %, and 9.05 %, respectively). In addition, the results showed that Se, I, and their combination (Se + I) activate different defense mechanisms in broccoli seedlings, enhancing the activity of antioxidant enzymes and the accumulation of osmoprotectants. Our results indicate that applying Se and I proved to be an effective strategy to alleviate low-temperature stress, significantly reducing leaf damage. These findings are promising since they allow for optimizing broccoli production in regions with cold climatic conditions, improving stress tolerance at critical stages of plant development, thus reducing agricultural losses associated with low temperatures.