Exogenous application of salicylic acid enhances seed germination in Apocynum venetum under salinity conditions

Abstract

Abstract Salinity stress significantly impairs seed germination and seedling establishment in many economically valuable plant species. Salicylic acid (SA) is a key signaling molecule implicated in plant stress responses. However, a significant knowledge gap remains regarding its concentration-dependent effects on Chinese hemp ( Apocynum venetum Zhengjun.), a species recognized for its ecological and pharmaceutical importance. In this study, we assessed the effects of exogenous SA application on seed germination, osmolytes (soluble sugar and protein contents), antioxidant enzyme activities, and lipid peroxidation (malondialdehyde content). Seed treated with 0.3 mM SA alleviated the adverse effects of salt stress on seed germination and seedling growth. Seeds of A. venetum treated with 0.3 mM SA had improved germination count, radicle length, plumule length, germination potential, chlorophyll content, soluble sugar and protein contents, enhanced the activities of superoxide dismutase, peroxidase, and catalase, and decreased malonaldehyde content in the seeds. These results demonstrate that exogenous application of SA enhances the accumulation of key osmolytes and photosynthetic pigments, and boosts antioxidant enzyme activities, thereby alleviating the adverse effects of salt stress on seed germination and seedling growth in A. venetum .