Genotype-Dependent Morphological and Antioxidant Responses of Wild Cherry (Prunus avium L.) to Salinity Stress In Vitro

Soil salinization is a major abiotic stressor limiting global agricultural and forestry productivity. This study aimed to assess the tolerance of four wild cherry (Prunus avium L.) genotypes (8-A, F-12, F-19, F-15) to salinity stress using the in vitro culture technique. Shoots were exposed to three NaCl concentrations (0—control treatment, 33, and 100 mM) in micropropagation medium under controlled laboratory conditions for 35 days. Morphological parameters, including shoot length, shoot number, survival and multiplication rate, shoot fresh and dry biomass, and shoot water content, were evaluated alongside biochemical markers such as total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities assessed through ferric reducing–antioxidant power (FRAP), ABTS radical scavenging, DPPH radical scavenging and nitric oxide (NO•) scavenging. Consistent with the experimental design, exposure to 100 mM NaCl significantly inhibited shoot growth and biomass accumulation, while survival was comparatively less affected. Genotypic variation was evident, with genotypes F-19 and F-12 demonstrating higher tolerance, maintaining greater growth and antioxidant capacity (FRAP and ABTS) under salt stress compared to more sensitive genotypes like 8-A and F-15. Phenolic and flavonoid contents were also reduced at 100 mM NaCl, suggesting that intense salinity stress limited the biosynthesis and accumulation of these antioxidant compounds. Nitric oxide scavenging activity remained largely unaffected by salinity in all genotypes, which may indicate that the applied stress levels were insufficient to markedly alter this component of the antioxidant response. The genotype F-19 emerged as the strongest salinity-tolerant genotype, retaining superior shoot number, multiplication rate, fresh/dry biomass and stable/increased total phenolic content (TPC) under 100 mM NaCl compared to other genotypes. This integrative in vitro approach effectively distinguished salt-tolerant wild cherry genotypes and offers a valuable screening tool for breeding and selection programmes targeting improved resilience to salinity stress. The findings have practical relevance for forestry, horticulture, landscape architecture and the restoration of salt-affected sites, particularly in the context of climate change. They also align with current European and global priorities focused on identifying genetically suitable reproductive material for resilient afforestation and ecosystem restoration under increased environmental stress.