| 1-Methylcyclopropene(1-MCP) could competitively combine with the ethylene receptor, block ethylene biosynthesis and its physiology effects,thus it could retard the ripening and senescence of fruit.In recent years,1-MCP has been becoming a hot topic in the field of postharvest physiology and storage in and abroad.'America No.8'apple was used as material in the experiment,to carry out the experinments on the following:(1)1-MCP treatment with various concentrations of 0.00(CK), 0.25,0.50,0.75,1.00μl·L-1;(2)1-MCP treatment with fumigating for 24 h at 20±0.5℃and 1/2 atmospheric pressure condition for 5 mins at 20±0.5℃.The destination of the experiment was to study the effect of 1-MCP on the quality attributes and postharvest physiology of fruit on stored(0±1℃)and on-shelf under room temperature(20±1℃).All these works will be an overview about the physiological and biochemical responses of fruit to 1-MCP,and illustrate its potential to understand the role of ethylene in fruit ripening and senescence processes and the effect of 1-MCP on fruit storage.We also expected that the results of this experiment would give a theoretical and practical support for the application of 1-MCP. The main results were as follows:(1)'America No.8'apple treated with 1-MCP had slower loss of firmness and acidity,and less of a change in peel color from green to yellow.'America No.8'apple responded very well to 1-MCP by both delay of ripening during storage life and maintenance of quality following cold storage.The optimum concentration of 1-MCP was 0.75μl·L-1 under the condition of fumigating for 24 h and 0.50μl·L-1 under the 1/2 atmospheric pressure condition for 5 mins at 20±0.5℃.(2)'America No.8'apple was typical climacteric fruit,and had the great peaks of respiration and ethylene production.1-MCP treatment with fumigating could significantly reduce the rates of respiration and ethylene production,being 79.26% and 56.88% of control during cold storage,and remarkably inhibited the height of respiration and ethylene peaks,being 21.81% and 53.74% lower than that of control,and postphoned the appearing time of respiration and ethylene peaks,being 10 days later than the control.1-MCP also inhibited respiration rate and ethylene production rate,being 49.01% and 73.36% of control during 7 days of shelf life at 20±1℃after cold storage.1-MCP treatment with 1/2 atmospheric pressure significantly reduced the rates of respiration and ethylene production,being 78.86% and 56.77% of control during cold storage,and remarkably degraded the height of respiration and ethylene peaks,being 28.85% and 56.55% lower than that of control,and postphoned the appearing time of respiration and ethylene peaks,being 10 days later than the control.(3)1-MCP was effective to maintain postharvest quality of fruit and provide longer storage life during cold storage and their respective 7 days of shelf life at 20±1℃.It significantly delayed the loss of firmness and titratable acidity,but had no significant effect on soluble solid content,and retarded the hydrolysis of starch,inhibited the acticity of amylase.(4)1-MCP could inhibit the increase of active oxygen contents and maintain higher the enzyme activities relating to active oxygen metabolism(SOD, CAT, POD and APX).1-MCP inhibited the increase of LOX activity,as well as decreased MDA content in certain degree.And all of them were contributed to delaying the ripening and senescence of fruit.
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