Comprehensive evaluation of high-temperature tolerance induced by heat priming at early growth stages in winter wheat

Priming is a potential way to enhance stress tolerance in plants. Winter wheat adaptation to harsh environmental conditions is a prominent global predicament. To enhance the productivity and its tolerance to rapidly changing world's environment, wheat plants were subjected to different heat priming events at early growth stages, which effects were studied on subsequent heat stress at booting and flowering stages. The study aimed to observe the major changes in photosynthetic characteristics, antioxidant enzymes system, and sugar metabolism in leaves during wheat adaptation to heat stress applied at booting and flowering stages after heat priming at early growth stage. Heat stress mostly affected the plant's development with a significant reduction in yield, yield components, biomass, osmotic potential (OP), leaf relative water potential (LRWP), and plant photosystem. However, the concomitant increase of membrane injury index (MII), reactive oxygen species (ROS) production, enzymatic activities, and sugar metabolism in primed plants enabled winter wheat plants to tolerate heat stress more after low heat priming (LP) than moderate heat priming (MP). Furthermore, MP at early growth stages reduced the biomass, OP, LRWP, and photosynthetic system while the remarkable increase in sugar metabolism and enzymatic activities increased the ROS production, yield, and yield components under heat stress applied at booting stage. Similarly, LP successfully improved plant tolerance to heat stress applied at flowering stage. In conclusion, LP at early growth stage was beneficial to sustain to heat stress during flowering stage, while MP at early growth stage helped winter wheat to better adapt to heat stress at booting stage. These results encompass a novel research direction for the adaptation of winter wheat to harsh environmental conditions to reduce yield loss.

Automated summary

Priming with heat stress in the early growth stage enhances stress tolerance in winter wheat, particularly at the booting and flowering stages. The study investigated changes in photosynthetic characteristics, antioxidant enzyme system, and sugar metabolism in leaves. Low heat priming improved winter wheat's adaptation and tolerance to heat stress, while moderate heat priming increased yield and tolerance at the booting stage. These findings provide a new research direction for reducing yield loss in winter wheat under harsh environmental conditions.