The multiple effects of hydrogen sulfide on cadmium toxicity in tobacco may be interacted with CaM signal transduction

•H2S alleviates photosynthetic damage in tobacco caused by Cd2+ through improved ETR and RUBISCO.•H2S alleviates damage of cell membrane and maintains the intracellular homeostasis by regulating the antioxidant system.•H2S stimulates the secretion of phytochelatins and resistant proteins, which forms a chelate with Cd2+.•H2S regulates the absorption and distribution of Ca2+ and K+ in leaves and roots, so that to antagonistic to Cd2+.•Resistance to Cd2+ mediated by H2S may be related by Ca2+ signal transduction.