Enhancing Lentil (Lens culinaris L.) Resilience: Exploring Salicylic Acid's Ameliorative Effects under Varied Planting Dates

Purpose: The limitation of crop yield due to terminal heat stress is a crucial factor. This stress arises from a delayed cultivation date, and its significance is further heightened by the potential influence of climate change on the existing temperature patterns. This study explored the ameliorative effects of Salicylic acid (SA) on various lentil plant parameters under different planting dates. Methods: The experiment employed a factorial design with four planting dates (January 2, January 12, January 22, and February 11) and four SA concentrations (0 mM, 0.5 mM, 1 mM, and 1.5 mM). Results: Late cultivation adversely affected parameters, but SA foliar spraying (1mM) improved them. Enzyme activities such as Catalase, Superoxide Dismutase, Ascorbate Peroxidase, and Guaiacol peroxidases increased at 11-Feb cultivation by 20%, 27%, 11%, and 20%, respectively, compared with control. Furthermore, chlorophyll content and Fv/Fm peaked on January 12, while 11-Feb exhibited the lowest values. Despite a decrease in soluble sugar at later sowing dates, proline content increased, indicating plant adaptive mechanisms against late-season heat stress. The principal component analysis revealed a significant correlation between root development, agronomic traits, and fluorescence parameters during cultivations on January 2 and 12, under 1mM SA treatment. Conversely, January 22 and February 11 combined with a 1.5mM SA treatments showed a stronger connection with enzymatic activities. This implies that delayed sowing, along with higher SA concentrations, distinctly influences the enzymatic processes in plants. Conclusions: Overall, January 12 is suggested as the optimal cultivation date for lentils, while SA application at 1 Mm during late cultivation in February mitigates the adverse effects of late-season heat stress. The findings suggest precise timing for lentil cultivation and the potential use of SA to mitigate heat stress, and provide insights for improving the resilience of lentil production in regions prone to late-season heat stress events.