Combined effects of EMS and NaCl-Induced salt stress on in vitro morphological and biochemical responses in sunflower (Helianthus annuus L.) genotypes

This study aimed to evaluate the interactive effects of ethyl methanesulfonate (EMS) and sodium chloride (NaCl) on the in vitro morphological and biochemical responses of two Helianthus annuus L. genotypes, 11TRC and PALANCI-I. Explants were exposed to varying concentrations of EMS at 1.0%, 1.5%, and 2.0% and NaCl at 1.25, 2.5, and 5.0 g/L, both individually and in combination. Morphological parameters such as shoot height, root length, fresh weight, number of leaves and nodes, and leaf dimensions were recorded. Biochemical evaluation was conducted through total phenolic content analysis. The results revealed that low to moderate EMS levels (1–1.5%) combined with mild salt stress (1.25–2.5 g/L NaCl) significantly enhanced growth and phenolic accumulation in the 11TRC genotype (p < 0.05). Conversely, higher EMS (2%) and NaCl (5.0 g/L) concentrations suppressed both morphological and biochemical traits in both genotypes. The 11TRC genotype displayed superior tolerance to combined EMS and salt treatments, indicating its potential for salt stress adaptation. These findings support the use of EMS as a useful tool in early-stage selection for salt tolerance in mutation breeding programs targeting sunflower improvement. These findings provide valuable insights for sunflower breeding programs and improve understanding of the mechanisms underlying stress tolerance under combined EMS and salt stress conditions. Salinity is a major abiotic stress factor that limits plant growth and productivity worldwide. The development of salt-tolerant genotypes is forsustainable agriculture. Ethyl methanesulfonate (EMS), a chemical mutagen, can induce genetic variation and improve plant responses to abiotic stresses. This study aimed to explore the interactive effects of EMS and NaCl treatments on morphological and biochemical traits of two Helianthus annuus L. genotypes. Two sunflower genotypes, 11TRC and PALANCI-I, were subjected to varying concentrations of EMS (1.0%, 1.5%, and 2.0%) and/or NaCl (1.25, 2.5, and 5.0 g/L), individually or in combination. Morphological traits such as plant height, root length, fresh weight, number of nodes and leaves, and leaf length and width were measured. The total phenolic content was analysed to assess biochemical responses. Statistical analysis was performed to determine the significance of the effects of treatment. Low to moderate EMS concentrations (1–1.5%) combined with mild NaCl stress (1.25–2.5 g/L) significantly improved plant growth and phenolic content in the 11TRC genotype (p < 0.05). Conversely, higher doses of EMS (2%) and NaCl (5.0 g/L) resulted in reduced morphological development and biochemical responses in both genotypes. Among the tested lines, 11TRC displayed superior tolerance to combined salt and EMS stress compared with PALANCI-I. These findings suggest combining EMS-induced mutagenesis with salt stress treatments can reveal genotype-specific stress adaptation mechanisms. EMS can be effectively used as a prescreening tool in mutation breeding programs aimed at enhancing salt tolerance in sunflower. This approach offers a promising strategy for selecting salt-susceptible genotypes at early developmental stages under controlled in vitro conditions.