Effect of nitric oxide on energy metabolism in postharvest banana fruit in response to chilling stress

• Chilling injury was alleviated by NO treatment in postharvest banana fruit.
• NO treatment maintained the level of ATP and energy charge.
• Enzyme activities involved in energy metabolism were enhanced by NO treatment.
• Energy status promoted by NO was correlated positively with chilling tolerance.

Effects of postharvest nitric oxide (NO) treatment on energy metabolism and chilling injury in cold-stored banana fruit were investigated. Banana fruit were treated with 0.05 mM NO donor sodium nitroprusside, and then stored at 7 °C for up to twenty days. NO treatment apparently inhibited the development of chilling injury. The contents of adenosine triphosphate (ATP) and energy charge in the NO-treated fruit were significantly higher than control fruit. Meanwhile, the activities of enzymes involved in energy metabolism, including H+-ATPase, Ca2+-ATPase, succinic dehydrogenase and cytochrome C oxidase were markedly enhanced by NO treatment. In addition, notably elevated activities of fructokinase, glucokinase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were observed in NO-treated banana fruit. These results indicated that NO could enhance chilling tolerance of banana fruit through maintaining high levels of energy status and inducing enzyme activities involved in energy metabolism during cold storage.