Effect of different 1-substituted cyclopropenes as ethylene inhibitors on postharvest physiology of apple stored at ambient temperature

Effects of three 1-substituted cyclopropenes with different branch chain lengths on postharvest physiology of 'Hanfu' apple were investigated. The apple were packed with plastic bags (0.02 mm) after being fumigated for 20 h with 0.75 μL/L 1-MCP (1-Methylcyclopropene), 2 μL/L 1-PentCP (1-pentylcyclopropene) and 0.5 μL/L 1-OCP (1-octylcyclopropene) respectively and then stored at ambient temperature (20℃). The results showed that 1-MCP and 1-PentCP treatments reduced ethylene production and respiration rate with respiration peak delayed by 4 days and ethylene peak by 8 days compared with those of control. Both treatments also delayed firmness loss and retarded the increase in soluble solids and malondialdehyde content, meanwhile, they retarded the changes of the activity of peroxidase, superoxide dismutase and catalase. However, malondialdehyde content increased with 1-OCP treated fruits that resulted in some detrimental effect during the late period of storage. It is suggested that both 1-MCP and 1-PentCP can be applied to inhibit physiological metabolism, maintain fruit quality, decrease membrane injury,and delay senescence of 'Hanfu' apple fruits.