Changes in ultrastructure, protease and caspase-like activities during flower senescence in Lilium longiflorum

► This is the first characterisation of petal senescence in L. longiflorum. ► The earliest senescence-related events preceded first visible signs of senescence. ► We report evidence for of a vacuole-driven programmed cell death. ► We show a rise in caspase-like activities late during senescence. ► This is the first report of caspase-like activities related to floral senescence.