The effect of external application of salicylic acid on some growth and biochemical indicators of rice (Oryza sativa) plants under salt stress
Subject Areas : Environmental physiology
1 - Department of Agronomy, Islamic Azad University of Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran
Keywords: Salicylic acid, Rice, Oxidative stress, Salt stress, Glutathione-ascorbic acid redox, Glyoxalase system,
Abstract :
Abiotic constraints, such as salinity stress, reduce cereal production. Exogenous application of salicylic acid (SA) can prevent the harm caused to rice by salinity, but the mechanisms by which it increases the tolerance of rice under salinity stress conditions are unclear. In this research, the effect of external application of SA on the growth and biochemical traits of rice plants under salinity stress was investigated as a factorial experiment based on a completely randomized design in hydroponic conditions. The results showed that salinity stress decreased photosynthetic pigments (chlorophyll and carotenoids), K/Na ratio, and glutathione-ascorbic acid redox state, and, as a result, rice plant growth. However, the application of SA improved the growth and height of rice plants by reducing the accumulation of hydrogen peroxide and malondialdehyde and increasing the activity of antioxidant enzymes. By maintaining K/Na homeostasis and glutathione-ascorbic acid redox states, SA improved plant tolerance and increased photosynthetic pigments in rice plants. SA also increased the accumulation of osmolytes, including free proline and soluble sugars, which can play an important role in modulating the osmotic potential of plant cells under salt stress. The obtained results show that the positive effects of the external application of SA on the accumulation of osmolytes, the K/Na ratio, and the antioxidant defense system lead to increased tolerance to salinity and improved growth of rice plants under salinity stress.
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