Soil salinity is a major abiotic stress that drastically hinders plant growth and development, resulting in lower crop yields and productivity. As one of the most consumed vegetables worldwide, tomato (Solanum lycropersicum L.) plays a key role in the human diet. The current study aimed to explore the differential tolerance level of two tomato varieties (Rio Grande and Agata) to salt stress. To this end, various growth, physiological and biochemical attributes were assessed after two weeks of 100 mM NaCl treatment. Obtained findings indicated that, although the effects of salt stress included noticeable reductions in shoots’ and roots’ dry weights and relative growth rate as well as total leaf area, for the both cultivars, Rio Grande performed better compared to Agata variety. Furthermore, despite the exposure to salt stress, Rio Grande was able to maintain an adequate tissue hydration and a high leaf mass per area (LMA) through the accumulation of proline. However, relative water content, LMA and proline content were noticeably decreased for Agata cultivar. Likewise, total leaf chlorophyll, soluble proteins and total carbohydrates were significantly decreased; whereas, malondialdehyde was significantly accumulated in response to salt stress for the both cultivars. Moreover, such negative effects were remarkably more pronounced for Agata relative to Rio Grande cultivar. Overall, the current study provided evidence that, at the early growth stage, Rio Grande is more tolerant to salt stress than Agata variety. Therefore, Rio Grande variety may constitute a good candidate for inclusion in tomato breeding programs for salt-tolerance and is highly recommended for tomato growers, particularly in salt-affected fields.

1. Li F, Xie Y, Chen X, et al. Distribution can be reflected by physiological responses to salinity of three submerged macrophytes from the Modern Yellow River Delta. Fundamental and Applied Limnology. 2011; 179(3): 159–167. doi: 10.1127/1863-9135/2011/0179-0159

2. Zhang L, Jiang Q, Zong J, et al. Effects of supplemental potassium on the growth, photosynthetic characteristics, and ion content of Zoysia matrella under salt stress. Horticulturae. 2024; 10: 31.

3. Zarai B, Walter C, Michot D, et al. Integrating multiple electromagnetic data to map spatiotemporal variability of soil salinity in Kairouan region, Central Tunisia. Journal of Arid Lands. 2022; 14: 186–202.

4. Munns R, Tester M. Mechanism of salinity tolerance. Annual Reviews in Plant Biology. 2008; 59: 651–681. doi: 10.1146/annurev.arplant.59.032607.092911

5. Parvin K, Hasanuzzaman M, Bhuyan MHMB, et al. Comparative physiological and biochemical changes in tomato (Solanum lycopersicumL.) under salt stress and recovery: role of antioxidant defense and glyoxalase systems. Antioxidants (Basel). 2019; 8(9): 350. doi: 10.3390/antiox8090350

6. Rahman A, Nahar K, Hasanuzzaman M, et al. Calcium supplementation improves Na+/K+ ratio, antioxidant defense and glyoxalase systems in salt-stressed rice seedlings. Frontiers in Plant Science. 2016; 7: 609.

7. Meng X, Zhou J, Sui N. Mechanisms of salt tolerance in halophytes: current understanding and recent advances. Open Life Science. 2018; 13: 149–154. doi: 10.1515/biol-2018-0020

8. Guo X, Xie Q, Li B, et al. Molecular characterization and transcription analysis of DNA methyltransferase genes in tomato (Solanum lycopersicumL.). Genetics and Molecular Biology. 2020; 43: e20180295. doi: 10.1590/1678-4685-GMB2018-0295

9. Guo M, Wang XS, Guo HD, et al. Tomato salt tolerance mechanisms and their potential applications for fighting salinity: A review. Frontiers in Plant Science. 2022; 13: 949541. doi: 10.3389/fpls.2022.949541

10. AdemGD, Roy SJ, Zhou M, et al. Evaluating contribution of ionic, osmotic and oxidative stress components towards salinity tolerance in barley. BMC Plant Biology. 2014; 14: 113. doi: 10.1186/1471-2229-14-113

11. Raziq A, Wang Y, Mohi Ud Din A, et al. A comprehensive evaluation of salt tolerance in tomato (Var. Ailsa Craig): responses of physiological and transcriptional changes in RBOH’s and ABA biosynthesis and signaling genes. International Journal of Molecular Sciences. 2022; 23: 1603.

12. Hdider C, Guezel I, Arfaoui K. Agronomic and qualitative evaluation of processing tomato cultivars in Tunisia. Acta Horticulturae. 2007; 758: 281–286.

13. Ilahy R, Tlili I, Pék Z, et al. Effect of individual and selected combined treatments with saline solutions and spent engine oil on the processing attributes and functional quality of tomato (Solanum lycopersicumL.) Fruit. Frontiers in Nutrition.2022; 9: 844162. doi: 10.3389/fnut.2022.844162

14. Horchani F, Mabrouk L, Borgi MA, et al. Foliar spray or root application: which method of salicylic acid treatment is more efficient in alleviating the adverse effects of salt stress on the growth of alfalfa plants, Medicago sativa L.? GesundePflanzen. 2023; 75(6):1–16.

15. Horchani F, Hajri R, Khayati H, et al. Does the source of nitrogen affect the response of subterranean clover to prolonged root hypoxia? Journal of Plant Nutrition and Soil Science.2010; 173(2): 275-283.

16. Manaa A, Gharbi E, Mimouni H, et al. Simultaneous application of salicylic acid and calcium improves salt tolerance in two contrasting tomato (Solanum lycopersicum) cultivars. South African Journal of Botany. 2014; 95: 32–39.doi:10.1016/J.SAJB. 2014.07.015

17. Sarker U, Oba S. The response of salinity stress-induced A. tricolor to growth, anatomy, physiology, non-enzymatic and enzymatic antioxidants. Frontiers in Plant Science. 2020; 11: 559876. doi: 10.3389/fpls.2020.559876.

18. Horchani F, Aloui A., Brouquisse R., et al. Physiological responses of tomato plants (Solanum lycopersicum) as affected by root hypoxia. Journal of Agronomy and Crop Science. 2008; 194(4): 297–303.

19. Wolf BA. comprehensive system of leaf analyses and its use for diagnosing crop nutrient status. Communications in Soil Science and Plant Analysis. 1982; 13(12): 1035–1059.

20. Boulila-Zoghlami L, Djebali W, Chaïbi W, et al. Modifications physiologiques et structurales induites par l’interaction cadmium-calcium chez la tomate (Lycopersicon esculentum). Comptes Rendus Biologies. 2006; 329(9): 702–711.

21. Wintermans J, Mots A. Spectrophotometric characteristic of chlorophylls a and b and their pheophytins in ethanol. BiochimicaBiophysica Acta.1965; 109(2): 448–453.

22. Bradford MA. Rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Analytical Biochemistry.1976; 72: 248–254.

23. Mc Cready RM, Guggolz J, Silviera V, et al. Determination of starch and amylase in vegetables, application to peas. Analytical Chemistry. 1950; 22(9): 1156–1158.

24. Bates LS, Waldren RP, Teari D. Rapid determination of free proline for water stress studies. Plant Soil. 1973; 39: 205–207. doi: 10.1007/BF00018060

25. Fu J, Huang B. Involvement of antioxidant and lipid peroxidation in the adaptation of two cool-season grasses to localized drought stress. Environmental and Experimental Botany. 2001; 45(2): 105–114.

26. Jaleel CA, Manivannan P, Wahid A, et al. Drought stress plants: a review on morphological characteristics and pigments composition. International Journal of Agriculture and Biology. 2009; 11(1): 100–105.

27. Zhou H, Shi H, Yang Y, et al. Insights into plant salt stress signaling and tolerance. Journal of Genetics and Genomics. 2024; 1(1): 16–34.

28. Bernstein N. Plants and salt: Plant response and adaptations to salinity. Model Ecosystems in Extreme Environments. Academic Press; 2019. pp. 101–112.

29. Cheesman J. Plant growth modelling without integrating mechanisms. Plant Cell and Environement. 2006; 16(2): 137–147.

30. Horchani F, Bouallegue A, Mabrouk L, et al. Nitrate reductase regulation in wheat seedlings by exogenous nitrate: A possible role in tolerance to salt stress. Journal of Plant Nutrition and Soil Science. 2023; 186(6): 633–646.

31. Menezes SPE,Sanglard LMVP,Ávila RT, et al.Photosynthetic and metabolic acclimation to repeated drought events play key roles in drought tolerance in coffee. Journal of Experimental Botany. 2017; 68(15): 4309–4322.

32. Falster DS, Westoby M. Plant height and evolutionary games. Trends in Ecology and Evolution. 2003; 18(7): 337–343.

33. Munns R. Physiological processes limiting plant growth in saline soils: some dogmas and hypotheses. Plant, Cell and Environment. 1993; 16(1): 15–24.

34. Pitann B, Schubert S, Mühling KH. Decline in leaf growth under salt stress is due to an inhibition of H+-pumping activity and increase in apoplastic pH of maize leaves. Journal of Plant Nutrition and Soil Science. 2009; 172(4): 535–543.

35. Hatzig S, Hanstein S, Schubert S. Apoplast acidification is not a necessary determinant for the resistance of maize in the first phase of salt stress. Journal of Plant Nutrition and Soil Science. 2010; 173(4): 559–562.

36. Horchani F, Bouallègue A, Abbes Z. Does jasmonic acid mitigate the adverse effects of salt stress on wheat through the enhancement of ascorbate biosynthesis and the induction of glutamate dehydrogenase activity? Journal of Plant Nutrition and Soil Science. 2024; 187(3): 356–366.

37. Yao XC, Meng LF, Zhao WL, et al. Changes in the morphology traits, anatomical structure of the leaves and transcriptome in Lyciumbarbarum L. under salt stress. Frontiers in Plant Science. 2023; 14: 1090366.

38. Gurmani AR, Wang X, Rafique M, et al. Exogenous application of gibberellic acid and silicon to promote salinity tolerance in pea (Pisum sativum L.) through Na+ exclusion. Saudi Journal of Biological Sciences. 2022; 29(6): 103305.

39. Ashraf M, Harris PJC. Photosynthesis under stressful environments: Anoverview.Photosynthetica.2013; 51: 163–190.

40. Sairam RK, Veerabhadra-Rao K, Srivastava GC. Differential response of wheat genotypes to long term salinity stress in relation to oxidative stress, antioxidant activity and osmolyte concentration. Plant Science. 2002; 163(5): 1037–1046.

41. Neelam S, Subramanyam R. Alteration of photochemistry and protein degradation of photosystem II from Chlamydomonas reinhardtii under high salt grown cells. Journal of Photochemistry and Photobiology. 2013; 124: 63–70.

42. AazamiMA, Rasouli F, Ebrahimzadeh A. Oxidative damage, antioxidant mechanism and gene expression in tomato responding to salinity stress underin vitroconditions and application of iron and zinc oxide nanoparticles on callus induction and plant regeneration.BMC Plant Biology. 2021; 21: 597.

43. Zhao S, Zhang Q, Liu M, et al. Regulation of plant responses to salt stress. International Journal of Molecular Sciecne. 2021; 22: 4609–4621.

44. Zhang M, Yanming F, Yonghua J, et al. Effects of salt stress on ion content, antioxidant enzymes and protein profile in different tissues of Broussonetia papyrifera. South African Journal of Botany. 2013; 85: 1–9.

45. Parida AK, Das AB. Salt tolerance and salinity effects on plants: A review. Ecotoxicology and Environmental Safety. 2005; 60(3): 324–349.

46. Hofius D, Bornke F. Photosynthesis, carbohydrate metabolism and source-sink relations. Potato Biology and Biotechnology. 2007; 13: 257–285.

47. Tarchoun N, Saadaoui W, Mezghani N, et al. The effects of salt stress on germination, seedling growth and biochemical responses of tunisian squash (Cucurbita maxima Duchesne) germplasm. Plants. 2022; 11: 800.

48. Alnusairi GS, Mazrou YS, Qari SH, et al. Exogenous nitric oxide reinforces photosynthetic efficiency, osmolyte, mineral uptake, antioxidant, expression of stress-responsive genes and ameliorates the effects of salinity stress in wheat. Plants (Basel). 2021; 10: 1693.

49. Abd-Elgawad H, Zinta G, Hegab MM, et al. High salinity induces different oxidative stress and antioxidant responses in maize seedlings organs. Frontiers in Plant Science. 2016; 7: 276. doi: 10.3389/fpls.2016.00276.

50. Souana K, Taïbi K, Ait-Abderrahim L, et al. Salt-tolerance in Vicia faba L. is mitigated by the capacity of salicylic acid to improve photosynthesis and antioxidant response. Scientia Horticulturae. 2020; 273: 109641.