Polyploidy-mediated divergent light-harvesting and photoprotection strategies under temperature stress in a Mediterranean carnation complex

•D. broteri showed inter-cytotype photochemical differences under heat and cold.•An approach based on chlorophyll fluorescence in detached leaves was found suitable.•2× and 4× cytotypes showed overall higher energy fluxes than 6× and 12× ones.•Light-harvesting and photoprotective responses to temperature stress were found.•Each cytotype exhibited a divergent strategy related to its environmental niche.