Comparison between the impacts of two different modes of salicylic acid application on tomato (Solanum lycopersicum) responses to salinity

Abstract

Exogenous application of salicylic acid may improve tolerance to salinity. To investigate whether exogenous salicylic acid application had similar protective effects when applied as a priming agent or concomitantly with NaCl, tomato seedlings primed or not with 10 µM salicylic acid were further treated with 125 mM NaCl, 10 µM salicylic acid or combined treatments. Both priming and concomitant application of salicylic acid increased plant growth of salt-stressed plants but their positive impact was not additive. The endogenous salicylic acid concentration increased in the leaves after concomitant application but not in response to priming, suggesting that salicylic acid accumulated during priming was metabolized subsequently. Priming increased Na and K accumulation in leaves of salt-treated plants while concomitant application had no impact on shoot Na and K accumulation. Both priming and concomitant salicylic acid decreased osmotic potential values in salt-treated plants. Carbon isotope discrimination showed that combination of both salicylic acid application methods were required to maintain a good water use efficiency in salt-treated plants. Our work demonstrated that both procedures of salicylic acid application have positive impact on salt resistance but that the underlying properties sustaining these adaptations differ according to application methods.

Effectiveness of different methods of salicylic acid application on growth characteristics of tomato seedlings under salinity

“…Foliar pretreatment with SA was the most effective method of SA application to recover plant growth under salinity. Similar results indicating the better effect of leaf pretreatment with SA have been also reported [13,27,32,36]. Despite roots are the first organ to face saline ions; however, leaves are the main and final target of toxic ions of salinity.…”

“…In another study, seed soaking or foliar pretreatment of SA provided similar tolerance effect in muskmelon under drought stress conditions [26]. In tomato plant, it has been shown that foliar application of SA generally induces tolerance to salinity stress [13,30]; however, seed soaking (priming) and root feeding of SA revealed contradictory results [8,30,37]. Application of 1 mM SA in nutrient solution of tomato plants reduced stomata conductance, CO 2 fixation and photosynthesis rates, resulting in the death of tomato plants [37].…”

Seed priming with salicylic acid potentiates water restriction-induced effects in tomato seed germination and early seedling growth

“…about the importance of the concentration of SA used for improve seed treatment according to the species studied. In tomatoes, Hayat et al (2008) found that plants subjected to water limitation were benefited by the application of SA of 10 µM, Senaratna et al (2000) showed that concentrations between 100-500 µM of SA induced a tolerance to multiple stresses, Gharbi et al (2018) improved tolerance to salt stress using 10 µM of SA. In none of these studies was applied seed priming with SA and water limitation simultaneously.…”

Transcriptional regulation-mediating ROS homeostasis and physio-biochemical changes in wild tomato (Solanum chilense) and cultivated tomato (Solanum lycopersicum) under high salinity

“…Similarly, positive correlation between salinity tolerance and K + retention have been evidenced in many salt sensitive plants like alfalfa ( Guo et al, 2016 ), mustard ( Chakraborty et al, 2016 ), wheat ( Wu et al, 2015 ), cucumber ( Redwan et al, 2016 ) and cotton ( Wang et al, 2017 ). It was suggested that Na + absorption pathway is highly dependent on K + channels and K + homeostasis under high NaCl concentration in wild species could be attributed due to tolerate high Na + endogenous concentration ( Gharbi et al, 2018 ). In a recent study, demonstrated the osmotic adjustment response of S. lycopersicum and S. chilense under 125 mM salt stress for 7 days, and reported contrasting behavior in the two with respect to modalities of osmotic adjustment and phyto-hormonal profiling.…”