Physiological and Biochemical Changes of Maize (Zea mays ‘MV500’) in Response to Heat Stress under Levels of Salicylic Acid
Esmail Nabizadeh, Narges Dolatmand, Masoud Haghshenas, Khadijeh AhmadiObjective: Heat stress is a significant factor leading to decreased crop yield. Exceeding the plant’s temperature tolerance threshold in ecosystems often results in significant cellular damage and potentially cellular death. Signaling elicitors may mitigate elevated temperatures’ detrimental impact and enhance plant defense mechanisms.
Materials and Methods: The present study investigates the influence of varying temperatures (25, 30, 35, 40, and 45°C) and pre-harvest salicylic acid (SA) application (0, 0.5, 1.5, 2.5, 5, and 10 mM) on the morpho-physiological and biochemical attributes of maize. A factorial-based experiment was set up following a completely randomized design and conducted in a growth room.
Results: The findings demonstrated that a 2.5 mM SA treatment at 35°C produced the largest plant leaf area and total chlorophyll content. The temperature and SA application interplay on carotenoid content were maximum at 5 mM. SA treatment under hightemperature conditions effectively elevated proline content, chl a, chl b, chl total, and malondialdehyde compared to untreated plants. The peak stomatal conductance was also observed with a 2.5 mM SA treatment at 30°C. The maximal catalase and peroxidase activities were recorded at 35°C. Furthermore, 2.5 mM SA at 25°C resulted in the highest levels of soluble proteins and RWC. SA (2.5 mM) applied at 30°C was more efficient at decreasing H2O2 production. The highest proline content was observed with 2.5 mM SA at 45°C.
Conclusion: SA(2.5 mM) treatment can have optimal effects on maize plant growth parameters under high-temperature conditions, potentially mitigating the damaging effects of heat stress.
