Direct observations of the redox states of frozen cherry buds by a unique in vivo ESR

• Published in: Biochemical and biophysical research communications 2003-10, Vol.310 (1), p.72-77
• Main Authors: Tada, Mika, Shiraishi, Takuo, Takashina, Tadashi, Ohya, Hiroaki, Ogata, Tateaki
• Format: Article
• Language: English
• Subjects: Bud; Carbamoyl-PROXYL; Cherry; Electron Spin Resonance Spectroscopy; ESR; Freezing damage; In vivo; Oxidation-Reduction; Prunus - chemistry; Redox
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2003.08.123

Low temperatures cause cellular damage in flower buds of the sweet cherry ( Prunus avium L. cv. Satohnishiki). In this study, the redox states within the cherry buds suffering freezing damage were non-destructively observed by a unique in vivo electron spin resonance (ESR) technique with a spin probe such as carbamoyl-PROXYL. The ESR signals of carbamoyl-PROXYL-treated bud were continuously recorded under freezing and thawing condition, which was decreased to approximately −4 °C and maintained for 1.5 h, and then returned to room temperature. Most of the buds began to freeze at −2.5 to −3.9 °C. The peak areas of the ESR signals significantly increased during the period of temperature rise. These results show that the reduced carbamoyl-PROXYL within the frozen bud was re-oxidized and became ESR-detectable while the bud was thawing. Our in vivo ESR technique has confirmed the oxidative transition of the redox states within the buds during thawing.