Hydrogen peroxide seed priming induces osmotic stress tolerance in soybean

Abstract Seed priming has emerged as a promising technique to improve seed germination and plant growth under water-limited conditions. However, a comprehensive understanding of the mechanisms involved in seed priming, particularly those related to post-dehydration processes and the subsequent acquisition of stress memory, remains limited. Thus, this study aimed to gain a better understanding of the effects of hydrogen peroxide (H 2 O 2 ) seed priming on germination and the transfer of stress memory from seeds to the vegetative stage (V4) of soybean plants, with impacts on plant growth, osmotic regulation, and oxidative stress under conditions of osmotic stress and rehydration. Therefore, an experiment was conducted using different concentrations of H 2 O 2 (0, 10, 50, 100, and 200 mM) for soybean seed priming under osmotic stress conditions. Subsequently, parameters related to seed germination, oxidative stress, osmotic adjustment, and seedling growth were assessed. Based on improved seed germination, seedling growth, and oxidative stress of seeds submitted to osmotic stress, the concentration of 10 mM of H 2 O 2 was chosen as the most promising for a subsequent experiment aiming to evaluate the effects of seed priming on soybean plants exposed to water restriction, followed by rehydration. The induction of stress memory in response to the seed priming was assessed by evaluating soil moisture, relative water content and leaf water potential, plant growth, proline accumulation, pigment, H 2 O 2 , and malondialdehyde content at the V4 stage. The evaluations were carried out at 0, 4, and 8 days after stress imposition and after a period of four days of rehydration. Seed priming with 10 mM H 2 O 2 slowed the water potential reduction, induced root growth, and reduced the content of proline and H 2 O 2 in stressed plants, although it did not avoid the reduction of pigments and increasing oxidative stress. We have successfully demonstrated the positive effects of H 2 O 2 seed priming inducing tolerance “stress memory” in soybean at the vegetative stage (V4).