| The effects of1-MCP with different concentrations on storage of banana (Musa spp. AAA Group cv.’Baxi’), mango (Mangifera indica L. cv.’Hongguifei’) and papaya (Carica papaya L. cv.’Risheng’) fruits stored at15℃were investigated. The changes in fruit quality, pectin substance, enzyme activities related to softening and cell structure were monitored and studied comparatively. The results were shown as follows:(1) Compared with the control, concentrations of0.5μL.L-1,1.0μL.L-1and2.0μL.L-11-MCP could effectively slow down the decrease in fruit firmness, delay the changes in peel colour, and significantly inhibit the increase in disease index and cell membrane permeability, which extended the shelf life of banana, mango and papaya fruits. In a word, the fresh-keeping effects of each concentration of1-MCP on banana, papaya and mango fruits were different.0.5μL.L-1and1.0μL.L-11-MCP were both beneficial to the preservation of banana fruit, while on inhibiting fruit diseases and peel colour change,0.5μL.L-11-MCP was a better choose. On the whole, the optimum concentration of1-MCP to mango and papaya fruits was1.0μL.L-1(2)1-MCP treatment not only significantly inhibited the occurrence of fruit diseases and the increase in cell membrane permeability, but also obviously retarded the reduction of fruit firmness and peel colour change. Meanwhile, the changes in content of TSS, Vc and TA were also effectively slowed down by1-MCP treatment. It suggested that1-MCP could maintain fruit storage quality and prolong the storage life of banana, mango and papaya fruits. However, responses of banana, mango and papaya fruits to1-MCP were different. The storage quality of banana, mango and papaya fruits treated with1-MCP appeared significant changes on the35th,15th and30th day, respectively (P<0.01).1-MCP had the best inhibitory effect on papaya fruit firmness, while on delaying changes in peel colour, TSS and TA of banana fruit was the best, mango fruit was the worst. Besides, banana and mango fruits treated with1-MCP could ripen and soften normally, while papaya fruit had the opposite response to1-MCP, and could not show normal quality and texture.(3)1-MCP treatment could significantly inhibit the rate of ethylene production and delay the appearing time of ethylene peak in banana,mango and papaya fruits, being10,5and10days later than that of control (P<0.01).1-MCP effectively reduced the value of ethylene peak in banana and mango fruits, being10.20%and9.41%lower than that of control (P<0.05). Meanwhile,1-MCP obviously restrained the activities of PG and cellulase, delayed the breakdown of propectin and accumulation of water soluble pectin (WSP), maintained higher fruit firmness, and delayed fruit ripening and softening process. In a word, the inhibitory effect of1-MCP on papaya fruit was the best, it was the worst for mango fruit.(4) The tissue structure of untreated banana, mango and papaya fruits changed significantly during storage. It showed that cell size gradually increased, cell arrangement became loosely and irregularly, intercellular space enlarged, peel cell wall gradually merged, flesh cell wall expanded and dissolved as flocs, protoplasm disintegrated, cell contents decreased, and cell regionalization system was seriously damaged. At the end of storage time, cell structure gradually collapsed, cell integrity loosed and physiological metabolic disordered, which resulted in fruit softening. The tissue structure of mango fruit changed rapidly, which of banana fruit changed slowly during storage. The appearing time of recession phenomenon in banana fruit tissue structure was10days later than that of mango fruit.1-MCP treatment significantly inhibited the changes in fruit tissue structure and protected the integrity of cell structure. Meanwhile,1-MCP had the most obvious inhibitory effect on papaya fruit, followed by banana fruit. Until the end of storage life (on the40th day), the flesh cells of papaya fruit were still packed closely, cell wall structure was integrity, and the cell structure had no obvious changes. However, the deterioration time of mango fruit tissue structure was only5days later than the control. In a word, the preserving effect of1-MCP on papaya fruit cell structure was the best, it was the worst for mango fruit. |
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