Independent and Interactive Effects of Salinity and Proline on Physiological and Biochemical Responses of Agave Plants
DOI:
https://doi.org/10.56946/jspae.v5i1.844Keywords:
Agave angustifolia, Salinity stress, Proline, Osmotic adjustment, Biochemical traits, Stress physiologyAbstract
Salinity is one of the most critical abiotic stresses limiting plant growth and productivity in arid and semi-arid regions. A pot experiment was conducted under greenhouse conditions at the National Research Centre, Giza, Egypt, during two successive seasons (2020–2021) to evaluate the effects of salinity stress and exogenous proline application on growth performance and biochemical attributes of Agave angustifolia var. pacifica. The experiment included four salinity levels (0, 20,000, 25,000, and 30,000 ppm NaCl) combined with three foliar proline concentrations (0, 100, and 200 ppm). Results showed that increasing salinity levels significantly reduced growth parameters, including plant height, leaf number, leaf area index, and root length. Similarly, photosynthetic pigments (chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll) were markedly decreased under salt stress. In contrast, salinity stress enhanced osmotic pressure, leaf electrical conductivity, and endogenous proline accumulation, indicating a strong stress response. Exogenous application of proline mitigated the adverse effects of salinity by improving chlorophyll stability, enhancing carbohydrate and protein content, and supporting osmotic adjustment under moderate stress conditions. However, its protective efficiency declined under severe salinity (30,000 ppm NaCl). Interaction analysis revealed that proline supplementation partially alleviated salinity-induced damage, improving the overall physiological performance of agave plants. These findings highlight the potential role of proline as a protective osmolyte and antioxidant in improving salinity tolerance. The study suggests that exogenous proline application can be an effective strategy to enhance the resilience and physiological stability of agave plants under saline environments.
References
1. Shrivastava P, Kumar R. Soil salinity: A serious environmental issue. Saudi Journal of Biological Sciences. 2015;22(2):123–131. https://doi.org/10.1016/j.sjbs.2014.12.001
2. Munns R, Tester M. Mechanisms of salinity tolerance. Annual Review of Plant Biology. 2008;59:651–681. https://doi.org/10.1146/annurev.arplant.59.032607.092911
3. Parihar P, Singh S, Singh R, Singh VP, Prasad SM. Effect of salinity stress on plants and its tolerance strategies. Environmental Science and Pollution Research. 2015;22(6):4056–4075. https://doi.org/10.1007/s11356-014-3739-1
4. Foyer CH, Noctor G. Stress-triggered redox signaling: what's in pROSpect? Plant, Cell & Environment. 2016;39(5):951–964. https://doi.org/10.1111/pce.12621
5. Ashraf M, Foolad MR. Roles of glycine betaine and proline in improving plant abiotic stress resistance. Environmental and Experimental Botany. 2007;59(2):206–216. https://doi.org/10.1016/j.envexpbot.2005.12.006
6. Gupta B, Huang B. Mechanism of salinity tolerance in plants. International Journal of Genomics. 2014;2014:701596. https://doi.org/10.1155/2014/701596
7. Szabados L, Savouré A. Proline: a multifunctional amino acid. Trends in Plant Science. 2010;15(2):89–97. https://doi.org/10.1016/j.tplants.2009.11.009
8. Hayat S, Hayat Q, Alyemeni MN, Wani AS, Pichtel J, Ahmad A. Role of proline under changing environments: a review. Plant Signaling & Behavior. 2012;7(11):1456–1466. https://doi.org/10.4161/psb.21949
9. Liang X, Zhang L, Natarajan SK, Becker DF. Proline mechanisms of stress survival. Antioxid Redox Signal. 2013 Sep 20;19(9):998-1011. https://doi.org/10.1089/ars.2012.5074.
10. El-Hefny EM, Abdelkader MA, El-Nady MF. Using multivariate analyses to evaluate the impact of proline foliar application under salinity stress on sugar beet yield. Bulletin of the National Research Centre. 2025;49:338. https://doi.org/10.1186/s42269-025-01338-y
11. Khan R, Maqsood M, Shahid M, et al. Use of proline to induce salt stress tolerance in guava. Plants. 2024;13(14):1887. https://doi.org/10.3390/plants13141887
12. Wang X, Liu Y, Chen Z, et al. Meta-analysis of proline metabolism genes in transgenic plants under drought and salinity stress. Plants. 2024;13(14):1913. https://doi.org/10.3390/plants13141913
13. Nobel PS. Physiological ecology of desert plants. Academic Press; 2010.
14. García-Moya E, Romero-Manzanares A, Nobel PS. Highlights for Agave productivity. GCB Bioenergy. 2011;3(1):1–15. https://doi.org/10.1111/j.1757-1707.2010.01078.x
15. Acosta-Motos JR, Ortuño MF, Bernal-Vicente A, Diaz-Vivancos P, Sanchez-Blanco MJ, Hernandez JA. Plant responses to salt stress: adaptive mechanisms. Agronomy.2017;7(1):18. https://doi.org/10.3390/agronomy7010018
16. Weather Atlas. Giza, Egypt - weather and climate data (historical records 2020–2021). 2021. https://www.weather-atlas.com/en/egypt/giza-climate
17. M. Saric, R. Kostrori, T. Cupina and I. Geric, “Chlorophyll Determination,” Univ. Noven Sadu Prakitikum is kiziologize Bilijaka Beogard, Haucana, Anjiga, 1967. p. 215.
18. Lichtenthaler HK. Chlorophylls and carotenoids: pigments of photosynthetic biomembranes. Methods in Enzymology. 1987;148:350–382. https://doi.org/10.1016/0076-6879(87)48036-1
19. Dubois M, Gilles KA, Hamilton JK, Rebers PA, Smith F. Colorimetric method for determination of sugars and related substances. Analytical Chemistry. 1956;28(3):350–356. https://doi.org/10.1021/ac60111a017
20. Gupta A, Singh S, Kundu SS, Jha N. Evaluation of tropical feedstuffs for carbohydrate and protein fractions by CNCP system. Indian Journal of Animal Sciences. 2011; 81(11):1154–1160.
21. Bates LS, Waldren RP, Teare ID. Rapid determination of free proline for water-stress studies. Plant and Soil. 1973;39(1):205–207. https://doi.org/10.1007/BF00018060
22. A.O.A.C., “Official Methods of Analysis, Association of Official Analytical Chemists,” 13th Edition, PO Box NO540, Benjamin Franklin Station, Washington DC, 1995..
23. Arvin, M. J. and Donnelly,D. J. (2008). Screening Potato Cultivars and Wild Species to Abiotic Stresses Using an Electrolyte Leakage Bioassay. Journal of Agricultural Science and Technology, 10(1), 33-42.
24. Snedecor GW, Cochran WG. Statistical Methods. 7th ed. Ames, Iowa: Iowa State University Press; 1982. p. 511.
25. Steel RGD, Torrie JH. Principles and Procedures of Statistics: A Biometrical Approach. 2nd ed. New York: McGraw-Hill; 1980.
26. Rizk MS, Assaha DVM, Mekawy AMM, et al. Comparative analysis of salinity tolerance mechanisms in two maize genotypes. BMC Plant Biology. 2024;24:818. https://doi.org/10.1186/s12870-024-05533-3
27.Kousik Atta K, Mondal SM, Gorai S, et al. Impacts of salinity stress on crop plants: improving salt tolerance through genetic and molecular dissection. Frontiers in PlantScience. 2023; 14:1241736. https://doi.org/10.3389/fpls.2023.1241736
28. Parida AK, Das AB. Salt tolerance and salinity effects on plants: a review. Ecotoxicology and Environmental Safety. 2005;60(3):324–349. https://doi.org/10.1016/j.ecoenv.2004.06.010
29. Santos, C.V. (2004) Regulation of Chlorophyll Biosynthesis and Degradation by Salt Stress in Sunflower Leaves. Scientia Horticulturae, 103, 93-99.http://dx.doi.org/10.1016/j.scienta.2004.04.009
30. Meena, M., Divyanshu, K., Kumar, S., Swapnil, P., Zehra, A., Shukla, V., Yadav, M., & Upadhyay, R. S. (2019). Regulation of L-proline biosynthesis, signal transduction, transport, accumulation and its vital role in plants during variable environmental conditions. Heliyon, 5(12), e02952. https://doi.org/10.1016/j.heliyon.2019.e02952
31. Kishor PBK, et al. Proline metabolism and its regulation in plants under stress. In: Hossain MA, et al., editors. Osmolytes and Plants Acclimation to Changing Environment. Springer; 2016. p. 45–65.
32.Sobahan MA. Effect of foliar application of proline on photosynthetic attributes, osmolyte and ion homeostasis in jute under salt stress. Asian Journal of Research in Crop Sciences. 2024;9(4):310–321. https://doi.org/10.9734/ajrcs/2024/v9i4320
33. Misra N, Gupta AK. Effect of salt stress on proline metabolism in green gram. Plant Science. 2005;169(2):331–339. https://doi.org/10.1016/j.plantsci.2005.02.013
34. Rady MM, Taha RS, Mahdi AHA. Proline enhances growth, productivity and anatomy of two varieties of Lupinus termis L. grown under salt stress.South African Journal of Botany SAJB-01375;1-7 2016 https://doi.org/10.1016/j.sajb.2015.07.007
35. El Moukhtari A, Cabassa-Hourton C, Farissi M, Savouré A. How does proline treatment promote salt stress tolerance during crop plant development? Frontiers in Plant Science. 2020;11:1127. https://doi.org/10.3389/fpls.2020.01127
36. Hare PD, Cress WA. Metabolic implications of stress-induced proline accumulation in plants. Plant Growth Regulation. 1997;21(2):79–102. https://doi.org/10.1023/A:1005703923347
37. Signorelli S. The fermentation analogy: proline accumulation in stressed plants. Frontiers in Plant Science. 2016;7:1339.https://doi.org/10.3389/fpls.2016.01339
38 . Rejeb IB, Pastor V, Mauch-Mani B. Plant responses to simultaneous biotic and abiotic stress: mechanisms and management. Plants. 2014;3(4):458–475. https://doi.org/10.3390/plants3040458
39. Acosta-Motos JR, Ortuño MF, Bernal-Vicente A, Diaz-Vivancos P, Sanchez-Blanco MJ, Hernandez JA. Plant responses to salt stress: adaptive mechanisms. Agronomy. 2017;7(1):18. https://doi.org/10.3390/agronomy7010018
Downloads
Published
How to Cite
Issue
Section
License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
