High oxygen facilitates wound induction of suberin polyphenolics in kiwifruit.

Abstract: BACKGROUND: Rapid wound healing would be critical for successful long‐term storage of fruits and vegetables. However, there was no direct evidence for the requirement and efficiency of oxygen in the fruit wound‐healing process. This study was conducted to investigate the role of oxygen in wound‐induced suberization by analyzing melanin, suberin polyphenolics (SPPs) and related enzymes in half‐cut kiwifruits exposed to 100%, 50%, 21% and 0% oxygen. RESULTS: By 3 days after wounding, the wound surface of kiwifruit in high (50 and 100%) oxygen appeared as a continuous layer of melanin and SPPs underneath, which effectively prevent excessive water vapor loss from the fruit halves. In contrast, melanin and SPPs deposition in the wound surface in 0% oxygen was significantly reduced, with high water vapor loss. Rapid decrease of soluble phenolic acids (caffeic, p‐coumaric, ferulic acids) was coupled with the increase of bound ferulic acid (coniferyl diacetate) especially in high oxygen by 9 days after wounding. Meanwhile, high oxygen enhanced peroxidase, catalase, phenylalanine ammonia‐lyase, and polyphenol oxidase activities. CONCLUSION: Oxygen is required for wound‐induced melanin and SPPs formation, and high oxygen is effective in promoting wound suberization in postharvest kiwifruit. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]