Carbon monoxide enhances the chilling tolerance of recalcitrant Baccaurea ramiflora seeds via nitric oxide-mediated glutathione homeostasis

► Chilling induced rapid generation of CO in Baccaurea ramiflora seeds. ► Chilling induced the accumulation of NO and glutathione. ► Exogenous CO or NO enhanced the seeds' tolerance to chilling. ► Exogenous CO or NO reduced reactive oxygen and nitrogen species overaccumulation under chilling. ► Glutathione modulated the tolerance of B. ramiflora seeds against chilling stress.