Heat Priming and Heat Stress Enhance Transgenerational Heat Tolerance in the Early Growth Stages of Oryza sativa L. Progeny

Rice (<i>Oryza sativa</i> L.) is a staple crop that provides essential nutrients and energy; however, it is sensitive to heat stress, posing a threat to sustainable productivity. Heat stress can cause delayed germination in progeny, increased oxidative stress, reduced biomass accumulation, and excessive water loss. Notably, heat stress memory induced through heat priming can be inherited, potentially strengthening heat tolerance in subsequent generations. This study examined the effects of heat priming and heat stress on delayed germination, shoot length, and shoot fresh and dry weight under elevated-temperature conditions. The results showed that while heat stress delayed germination in progeny, heat priming significantly accelerated germination rates. Furthermore, heat stress elevated oxidative stress levels, thereby hindering biomass synthesis. In contrast, heat priming helped maintain low levels of reactive oxygen species (ROS) and malondialdehyde (MDA), contributing to greater biomass accumulation. These findings suggest that heat priming enhances transgenerational heat tolerance in rice, leading to faster germination, higher biomass accumulation, and improved ROS homeostasis in progeny.