Effects of salicylic acid application on two almond cultivars under salinity stress
Summary
The effects of salinity stress on the physiological processes and biochemical compounds of plants were reported. Salicylic acid (SA), as one of the main phytohormones, is a signal molecule that alleviates the negative influences of salinity. This study was conducted to investigate the protective role of SA in improving the salinity tolerance of two almond cultivars. Two almond cultivars ('Tuono' and 'Sahand') grafted on the GN (Garnem) rootstock were exposed to different levels of salinity stress (0, 2, 6 and 8 dS·m-1) and treated with SA (0, 1 and 2 mM). The results showed that salinity stress significantly reduced the plant height, Fv/Fm, protein and total phenolic content (TPC), whereas Na and Cl content in roots, proline content and antioxidant enzymes activities, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POD) and glutathione peroxidase (GPX), significantly increased in response to salinity stress. Rootstock and scion diameter, and also leaves number of selected shoots significantly increased at 2 and 6 dS·m-1 of salinity, and then significantly decreased at 8 dS·m-1 of salinity. Furthermore, it was found SA treatment significantly alleviated the negative effects of salinity by enhancing morphological characteristics, Fv/Fm, accumulation of Na and Cl in roots, proline content, protein and TPC and also by enhancing the SOD, CAT, APX, POD and GPX activities. Taken together, the results showed that 'Sahand' cultivar treated with SA had a better response to salinity stress compared with 'Tuono' cultivar. Therefore, the use of 'Sahand' cultivar and application of SA could be recommended as a practical tool under salinity conditions.
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