Morphological and physiological characteristics for evaluation of salicylic acid effects on Celosia argentea L. under salinity stress

Salinity stress is one of the most important abiotic stresses in agriculture, affecting about 20% of the total land cover. Salicylic acid (SA) plays an important role in plant tolerance to salinity stress and reducing its damages. In view of the importance of Celosia argentea, a factorial experiment was conducted based on a completely randomized design with three replications to investigate the mitigating role of SA on C. argenea plants under salinity. The factors included salinity in four levels (0, 40, 80, and 120 mM NaCl) and SA at three levels (0, 1, and 2 mM). Results showed that the effects of salinity stress on morphological and physiological characteristics were significant, in terms of a negative effect on growth and flowering of C. argentea. Foliar application of SA, especially at 1mM concentration, improved the morphological and physiological characteristics of the plants. Correlation between the measured traits showed that proline, malondialdehyde (MDA), and electrolyte leakage had a significant negative correlation with the other measured traits. As stress increased, stomatal conductance decreased, indicating closure of stomata during stress and plant resistance. In general, SA application increased photosynthesis rate through the improvement of plant pigments and proline contents under salinity stress. Therefore, because of its low costs and compatibility with the environment, SA is recommended as a simple solution to reduce salinity stress in this plant.