Sucrose treatment suppresses programmed cell death in broccoli florets by improving mitochondrial physiological properties

The effect of sucrose treatment on mitochondrial membrane potential (Delta Psi m), contents of reactive oxygen species (ROS), cytochrome c oxidase (COX) activity, alternative oxidase (AOX) activity, mitochondrial Ca2+ content and cytochrome c release from mitochondria in broccoli florets during storage at 20 degrees C was investigated. The results showed that sucrose treatment effectively retarded the onset of programmed cell death (PCD) in broccoli florets by a mitochondria-dependent pathway. Sucrose treatment inhibited the increase of ROS and a decrease in Delta Psi m, which was associated with the open state of permeability transition pore (PTP) and the ratio of cytochrome c/a. The decrease of COX activity and Ca2+ content in broccoli florets was suppressed under sucrose treatment. Sucrose treatment maintained higher AOX activity, and retarded the cytochrome c release from mitochondria. These results indicated that sucrose treatment delayed the appearance of PCD in broccoli florets through improving mitochondrial physiological properties.