Boran İKİZ ,
Sibel BALIK ,
Kadir YILMAZ ,
Yıldız DAŞGAN ,
Tuğçe TEMTEK ,
Hatice DEMİRCİOĞLU
Çukurova University, Faculty of Agriculture, Department of Horticulture, Adana
Abstract
This study evaluated the effectiveness of different biostimulants—amino acids, plant growth-promoting rhizobacteria (PGPR), fulvic acid, chitosan, and vermicompost—in improving the morphological, physiological, biochemical, and nutritional responses of hydroponically grown celery (Apium graveolens L.) under salt stress. Salinity markedly impaired plant performance, reducing shoot fresh weight, leaf number, leaf area, and yield by 27%, 29%, 39%, and 29%, respectively. Among the tested treatments, PGPR produced the most consistent overall response, increasing yield by 35% relative to salt-stressed plants and restoring it to a level statistically comparable with the non-saline control. PGPR also maintained leaf relative water content at 96.3% and reduced the membrane injury index from 34% under salinity to approximately 20%. Vermicompost similarly improved membrane stability and promoted the accumulation of essential macro- and micronutrients, particularly K, Mg, Fe, and Zn, although its 17% increase in yield was not statistically significant. Fulvic acid produced favorable numerical responses in total phenolic and flavonoid contents. Nitrate concentrations remained low across treatments, with a maximum value of 482 mg kg⁻¹ FW. As a result, PGPR was the most effective single biostimulant for sustaining yield, plant water status, and membrane integrity, whereas vermicompost provided complementary benefits by improving mineral nutrition and physiological resilience under salinity.
📄Alfosea-Simón, M., Zavala-Gonzalez, E.A., Camara-Zapata, J.M., Martínez-Nicolás, J.J., Simón, I., Simón-Grao, S., García-Sánchez, F., 2020. Effect of foliar application of amino acids on the salinity tolerance of tomato plants cultivated under hydroponic system. Scientia Horticulturae, 272: 109509.
📄Al-Huqail, A.A., Aref, N.M., Khan, F., Sobhy, S.E., Hafez, E.E., Khalifa, A.M., Saad-Allah, K.M., 2024. Azolla filiculoides extract improved salt tolerance in wheat (Triticum aestivum L.) is associated with prompting osmostasis, antioxidant potential and stress-interrelated genes. Scientific Reports, 14(1): 11100.
📄Alrasheed, R., Naamala, J., Subramanian, S., Smith, D.L., 2026. PGPR cell-free supernatants as metabolite-based biostimulants for alleviating salinity stress in plants. Frontiers in Plant Science, 17: 1824871.
📄Anonymous, 2015. Faostat Database Collection. Food and Agriculture Organization of the United Nations, (http://www.fao.org/faostat/) (Accessed: 10.01.2026)
📄Anonymous, 2023. Faostat: Database for crops and production statistics. Food and Agriculture Organization of the United Nations
📄Badavath, H., Saski, C.A., 2026. Plant adaptation to salinity: physiological pathways and prospects for crop improvement-A review. Genes, 17(3): 253.
📄Badr, M.A., El-Tohamy, W.A., Abou-Hussein, S.D., Gruda, N.S., 2020. Deficit irrigation and arbuscular mycorrhiza as a water-saving strategy for eggplant production. Horticulturae, 6(3): 45.
📄Bakhoum, G., Sadak, M., Tawfic, M., 2022. Chitosan and chitosan nanoparticle effect on growth, productivity and some biochemical aspects of Lupinus termis L. plant under drought conditions. Egyptian Journal of Chemistry, 65(5): 537–549.
📄Baum, C., El-Tohamy, W., Gruda, N., 2015. Increasing the productivity and product quality of vegetable crops using arbuscular mycorrhizal fungi: a review. Scientia Horticulturae, 187: 131–141.
📄Benazzouk, S., Dobrev, P.I., Djazouli, Z.E., Motyka, V., Lutts, S., 2020. Positive impact of vermicompost leachate on salt stress resistance in tomato (Solanum lycopersicum L.) at the seedling stage: a phytohormonal approach. Plant and Soil, 446(1): 145-162.
📄Beykkhormizi, A., Abrishamchi, P., Ganjeali, A., Parsa, M., 2016. Effect of vermicompost on some morphological, physiological and biochemical traits of bean (Phaseolus vulgaris L.) under salinity stress. Journal of Plant Nutrition, 39(6): 883–893.
📄Bhanja, S.N., Mukherjee, A., Rodell, M., 2018. Groundwater storage variations in India. In: Mukherjee, A. (Ed.), Groundwater of South Asia. Springer, Singapore, pp. 49–59.
📄Bharti, N., Barnawal, D., 2019. Amelioration of salinity stress by PGPR: ACC deaminase and ROS scavenging enzymes activity. In: Singh, A.K., Kumar, A., Singh, P.K. (Eds.), PGPR Amelioration in Sustainable Agriculture. Woodhead Publishing, pp. 85–106.
📄Bisbis, M.B., Gruda, N.S., Blanke, M.M., 2019. Securing horticulture in a changing climate-A mini review. Horticulturae, 5(3): 56.
📄Bonasia, A., Lazzizera, C., Elia, A., Conversa, G., 2017. Nutritional, biophysical and physiological characteristics of wild rocket genotypes as affected by soilless cultivation system, salinity level of nutrient solution and growing period. Frontiers in Plant Science, 8: 300.
📄Breś, W., Kleiber, T., Markiewicz, B., Mieloszyk, E., Mieloch, M., 2022. The effect of NaCl stress on the response of lettuce (Lactuca sativa L.). Agronomy, 12(2): 244.
📄Bulgari, R., Franzoni, G., Ferrante, A., 2019. Biostimulants application in horticultural crops under abiotic stress conditions. Agronomy, 9(6): 306.
📄Celebi, G.C., Balik, S., Dasgan, H.Y., 2026. Fulvic acid, chitosan, and amino acids improve productivity and bioactive composition of hydroponically grown parsley. Horticulturae, 12(1): 68.
📄Conversa, G., Bonasia, A., Lazzizera, C., La Rotonda, P., Elia, A., 2021. Reduction of nitrate content in baby-leaf lettuce and Cichorium endivia through the soilless cultivation system, electrical conductivity and management of nutrient solution. Frontiers in Plant Science, 12: 645671.
📄Dasgan, H.Y., Temtek, T., 2022. Impact of biofertilizers on plant growth, physiological and quality traits of lettuce (Lactuca sativa L. var. longifolia) grown under salinity stress. In: Hufnagel, L., El-Esawi, M.A. (Eds.), Vegetation Dynamics, Changing Ecosystems and Human Responsibility. IntechOpen
📄Fang, Y., Xiong, L., 2015. General mechanisms of drought response and their application in drought resistance improvement in plants. Cellular and Molecular Life Sciences, 72(4): 673–689.
📄Fardus, J., Hossain, M.S., Fujita, M., 2021. Modulation of the antioxidant defense system by exogenous L-glutamic acid application enhances salt tolerance in lentil (Lens culinaris Medik.). Biomolecules, 11(4): 587.
📄Giménez, A., Fernández, J.A., Pascual, J.A., Ros, M., Saez-Tovar, J., Martinez-Sabater, E., Egea-Gilabert, C., 2020. Promising composts as growing media for the production of baby leaf lettuce in a floating system. Agronomy, 10(10): 1540.
📄Gruda, N.S., 2019. Increasing sustainability of growing media constituents and stand-alone substrates in soilless culture systems. Agronomy, 9(6): 298.
📄Gruda, N.S., 2022. Advances in soilless culture and growing media in today’s horticulture-An editorial. Agronomy, 12(11): 2773.
📄Gruda, N., Savvas, D., Colla, G., Rouphael, Y., 2018. Impacts of genetic material and current technologies on product quality of selected greenhouse vegetable-A review. European Journal of Horticultural Science, 83(11): 319–328.
📄Hualpa-Ramirez, E., Carrasco-Lozano, E.C., Madrid-Espinoza, J., Tejos, R., Ruiz-Lara, S., Stange, C., Norambuena, L., 2024. Stress salinity in plants: New strategies to cope with in the foreseeable scenario. Plant Physiology and Biochemistry, 208: 108507.
📄Ikiz, B., Dasgan, H.Y., Balik, S., Aldiyab, A., Gruda, N.S., 2025. Improved salt stress resilience, growth, and quality of soilless basil through biostimulant application. Scientific Reports, 15(1): 35522.
📄Ikiz, B., Dasgan, H.Y., Balik, S., Kusvuran, S., Gruda, N.S., 2024. The use of biostimulants as a key to sustainable hydroponic lettuce farming under saline water stress. BMC Plant Biology, 24(1): 808.
📄Jaros-Tsoj, K., Jaroszuk-Ściseł, J., Oleńska, E., Sugier, P., Rineau, F., Vassilev, A., Vangronsveld, J., Wójcik, M., 2026. Biostimulants for sustainable agriculture: Enhancing plant growth and stress resilience. Applied Sciences, 16(10): 4685.
📄Kizilgeci, F., Yildirim, M., Islam, M.S., Ratnasekera, D., Iqbal, M.A., Sabagh, A.E., 2021. Normalized difference vegetation index and chlorophyll content for precision nitrogen management in durum wheat cultivars under semi-arid conditions. Sustainability, 13(7): 3725.
📄Kurunc, A., 2021. Effects of water and salinity stresses on growth, yield, and water use of iceberg lettuce. Journal of the Science of Food and Agriculture, 101(13): 5688–5696.
📄Miller, G.A.D., Suzuki, N., Ciftci-Yilmaz, S., Mittler, R., 2010. Reactive oxygen species homeostasis and signalling during drought and salinity stresses. Plant, Cell & Environment, 33(4): 453–467.
📄Minhas, P.S., Ramos, T.B., Ben-Gal, A., Pereira, L.S., 2020. Coping with salinity in irrigated agriculture: Crop evapotranspiration and water management issues. Agricultural Water Management, 227: 105832.
📄Moncada, A., Vetrano, F., Miceli, A., 2020. Alleviation of salt stress by plant growth-promoting bacteria in hydroponic leaf lettuce. Agronomy, 10(10): 1523.
📄Ozturk, M., Turkyilmaz Unal, B., García-Caparrós, P., Khursheed, A., Gul, A., Hasanuzzaman, M., 2021. Osmoregulation and its actions during the drought stress in plants. Physiologia Plantarum, 172(2): 1321–1335.
📄Parveen, Anwar-Ul-Haq, M., Aziz, T., Aziz, O., Maqsood, L., 2021. Potassium induces carbohydrates accumulation by enhancing morpho-physiological and biochemical attributes in soybean under salinity. Archives of Agronomy and Soil Science, 67(7): 946–959.
📄Paul, D., Lade, H., 2014. Plant-growth-promoting rhizobacteria to improve crop growth in saline soils: a review. Agronomy for Sustainable Development, 34(4): 737–752.
📄Peña Calzada, K., Olivera Viciedo, D., Habermann, E., Calero Hurtado, A., Lupino Gratão, P., De Mello Prado, R., Rodríguez, J.C., 2022. Exogenous application of amino acids mitigates the deleterious effects of salt stress on soybean plants. Agronomy, 12(9): 2014.
📄Qadir, M., Wichelns, D., Raschid-Sally, L., McCornick, P.G., Drechsel, P., Bahri, A., Minhas, P.S., 2010. The challenges of wastewater irrigation in developing countries. Agricultural Water Management, 97(4): 561–568.
📄Rouphael, Y., Colla, G., 2020. Biostimulants in agriculture. Frontiers in Plant Science, 11: 40.
📄Sadak, M.S., Dawood, M.G., 2023. Biofertilizer role in alleviating the deleterious effects of salinity on wheat growth and productivity. Gesunde Pflanzen, 75(4): 1207–1219.
📄Sadak, M.S., Hanafy, R.S., Elkady, F.M., Mogazy, A.M., Abdelhamid, M.T., 2023. Exogenous calcium reinforces photosynthetic pigment content and osmolyte, enzymatic, and non-enzymatic antioxidants abundance and alleviates salt stress in bread wheat. Plants, 12(7): 1532.
📄Samarakoon, U.C., Weerakkody, W.A.P., 2010. Modification of nutrient supply in soilless media for improved growth and yield of celery (Apium graveolens L.). Tropical Agricultural Research, 21(3): 336–345.
📄Ullah, A., Bano, A., Khan, N., 2021. Climate change and salinity effects on crops and chemical communication between plants and plant growth-promoting microorganisms under stress. Frontiers in Sustainable Food Systems, 5: 618092.
📄Zafar-ul-Hye, M., Danish, S., Abbas, M., Ahmad, M., Munir, T.M., 2019. ACC deaminase producing PGPR Bacillus amyloliquefaciens and Agrobacterium fabrum along with biochar improve wheat productivity under drought stress. Agronomy, 9(7): 343.
📄Zhang, P., Zhang, H., Wu, G., Chen, X., Gruda, N., Li, X., Duan, Z., 2021. Dose-dependent application of straw-derived fulvic acid on yield and quality of tomato plants grown in a greenhouse. Frontiers in Plant Science, 12: 736613.
📄Zhou, Y., Zheng, J., Li, Y., Xu, D.P., Li, S., Chen, Y.M., Li, H.B., 2016. Natural polyphenols for prevention and treatment of cancer. Nutrients, 8(8): 515.
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Sibel BALIK