The Effect Of High Oxygen On Fruit Quality And Ripening In Kiwifruit

Kiwifruit,as a typical climacteric fruit,needs a long time to finish the postharvest ripening and reach the eating stage.‘Hayward’（Actinidia chinensis var.deliciosa‘Hayward’）and‘Xuxiang’（Actinidia chinensis var.deliciosa‘Xuxiang’）kiwifruit were exposed to high oxygen（30%O₂ and 40%O₂）for 7 days at room temperature（23±1℃）.In current study,we evaluated the effects of high oxygen（30%O₂ and 40%O₂）on fruit quality and ripening of kiwifruit.Compared to the control:1.30% O₂ and 40% O₂ accelerated the decrease of firmness of‘Hayward’and‘Xuxiang’kiwifruit.Kiwifruit exposure to 30%O₂ or 40%O₂ both required 7 days to reach the eating firmness while the control fruit needed 42 days.The treated fruit exhibited a dramatically increase in SSC,a rapidly decrease in firmness,TA and starch,and accompanied by the obvious change of flesh colors.The amount of ester increased while aldehyde decreased in‘Hayward’and‘Xuxiang’kiwifruit as fruit softened.30%O₂ accelerated the change of composition and concentrations of volatile compounds.2.When‘Hayward’and‘Xuxiang’kiwifruit reached the eating firmness,there were no significant differences of SSC,TA and flesh color between 30%O₂ and 40%O₂ treated kiwifruit（P>0.05）,and no significant difference between the high oxygen treatment group and the control group（P>0.05）.When‘Hayward’and‘Xuxiang’kiwifruit reached the eating firmness,there were no significant differences in flavor quality between 30%O₂ treated and untreated fruit according to the sensory score（P>0.05）.4.30% O₂ increased ethylene production,respiration rate,energy production and level of ATP,ADP,AMP and EC in‘Hayward’kiwifruit.30%O₂ increased CAT and POD activities in‘Hayward’kiwifruit.30%O₂ up-regulated the expression of Ac ACS,Ac ACO,Ac ACO2,Ad AAC1,Ad AOX2,Ac EXP1,Ac PL1 and Ac PG in‘Hayward’kiwifruit.