title: Maturity-dependent chilling tolerance regulated by the antioxidative capacity in postharvest cucumber (Cucumis sativus L.) fruits.
abstract: BACKGROUND
  The aim of the present study was to reveal the effect of fruit maturity on the chilling tolerance of cucumber (Cucumis sativus L.) fruit and the oxidative and antioxidative mechanisms involved. Chinese mini-cucumber (cv. Hangcui-1) fruits were harvested at four developmental stages: Immature (3-8 days after anthesis (DAA)), Mature (9-16 DAA), Breaker (17-22 DAA) and Yellow (35-40 DAA). All fruits were stored at 2 °C for 9 days and rewarmed at 20 °C for 2 days.
  
  
  RESULTS
  The chilling injury index declined with advancing fruit maturity. High superoxide anion radical production rate and hydrogen peroxide content were observed in Immature fruits after cold storage and rewarming. Under chilling stress, superoxide dismutase showed an early response. Fruits at earlier maturity stages exhibited higher catalase, ascorbate peroxidase and monodehydroascorbate reductase activities and glutathione content as well as its redox state, and lower peroxidase, dehydroascorbate reductase and glutathione reductase activities and ascorbate content as well as its redox state.
  
  
  CONCLUSIONS
  Fruits at the earlier developmental stage are more susceptible to chilling injury, which is related to increased oxidative stress. High peroxidase activity and ascorbate content and maintenance of the latter's redox state appear critical to the chilling tolerance of cucumber fruits at later developmental stages.
authors.affiliation: College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: Chunlu
authors.initials: C
authors.lastname: Qian
authors.forename: Zhiping
authors.initials: Z
authors.lastname: He
authors.forename: Yuying
authors.initials: Y
authors.lastname: Zhao
authors.forename: Hongbo
authors.initials: H
authors.lastname: Mi
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Chen
authors.forename: Linchun
authors.initials: L
authors.lastname: Mao
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D060387:Ascorbate Peroxidases / Q000032:analysis; D001205:Ascorbic Acid / Q000032:analysis; D002374:Catalase / Q000032:analysis; D003080:Cold Temperature; D018553:Cucumis sativus; D005638:Fruit / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development*; D005978:Glutathione / Q000032:analysis; D006861:Hydrogen Peroxide / Q000032:analysis; D009247:NADH, NADPH Oxidoreductases / Q000032:analysis; D013481:Superoxides / Q000032:analysis
chemical_list: D000975:Antioxidants; D013481:Superoxides; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D009247:NADH, NADPH Oxidoreductases; C023927:monodehydroascorbate reductase (NADH); D005978:Glutathione; D001205:Ascorbic Acid