| In this study,a new red-fleshed apple cultivar‘Meihong’was used as a test material to study the room temperature（20?25℃）,low temperature（0±0.5℃）and low temperature combined with 1-MCP(1μL·L-1),after which several fruit characteristics were evaluated（i.e.,firmness,ethylene release rate,aroma components,fruit softening-related enzyme activities,and related gene expression）.To clarify the storage-induced changes to fruit quality and the underlying regulatory mechanism,which provided the promotion,application,production and sales theoretical basis and technical support of‘Meihong’.The main results indicated that:1.During the storage period,the fruit firmness of‘Meihong’fruits showed a downward trend.After 20 days of room temperature storage,the fruit firmness of‘Meihong’fruits decreased by 24.6%,and the fruit firmness was better,while that of‘Golden delicious’fruits decreased by 50.2%.The fruit skin slightly shrunk and pulp softed,and the decline of‘Meihong’fruits were significantly smaller than that of‘Golden delicious’fruits.The storage of low temperature and low temperature combined with 1-MCP the fruit firmness of’Meihong’decreased by 20.9%and 12.3%during 80 days,respectively,and the fruit remained basically fresh.Low temperature combined with 1-MCP storage can better delay the decline of fruit firmness.2.The ACS1 genotypes of‘Meihong’and‘Golden delicious’fruits were heterozygous ACS1-1/-2,but the ethylene release rate of‘Meihong’fruits were significantly lower than that of‘Golden delicious’fruits at room temperature and low temperature.Low temperature combined with 1-MCP treatment could significantly inhibit the production of ethylene in the fruit,thereby delaying the decline of fruit firmness.Analysis of the gene expression levels of the key enzymes for ethylene synthesis revealed that the expression levels of the‘Meihong’fruits ACO and ACS1 genes were both lower than that of‘Golden delicious’fruits,which were consistent with the trend of ethylene release rate.3.The activities and gene expression levels ofα-L-Af,β-Gal,PG,PME,AM of‘Meihong’fruits were significantly lower than those of‘Golden delicious’fruits under different conditions.The activities and gene expression levels of the five enzymes were significantly inhibited and increased slowly,and the 1-MCP treatment had a better inhibitory effect.4.The total aroma content of‘Meihong’fruits were lower than that of‘Golden delicious’fruits,and aroma components of‘Meihong’fruits were mainly aldehyde and alcohol.The aldehyde content of‘Meihong’fruits decreased during storage at room temperature,and the contents of alcohol and ester increased,and the aroma release of fruits after low temperature combined with 1-MCP and low temperature treatments were significantly delayed,and the contents of ester and alcohol of fruit after 1-MCP treatment were suppressed.Analysis of the expression levels of key genes in the aroma synthesis pathway found that the expression levels of LOX and AAT in‘Meihong’fruits were lower than those in‘Golden delicious’fruits,which were in line with the trend of changes in aroma component contents.5.The contents of vitamin C（VC）,titratable acid（TA）,soluble solids（TSS）,phenolic compounds,and antioxidant capacity of‘Meihong’fruits during storage were higher than those of‘Golden delicious’fruits.Low temperature and low temperature combined with1-MCP treatment delayed the decrease of VC,TA,TSS and phenolic compounds contents.The results showed that the ethylene release rate,ester component content,fruit softening related enzymes activities and related gene expression levels of’Meihong’fruits were low,and the contents of VC and phenolic compounds were high.Low temperature and low temperature combined with 1-MCP kept its fresh quality to a certain extent after 80 days.so‘Meihong’fruits have significantly better storage resistance than‘Golden delicious’fruits,and can be used for long-term high-end market supply through low-temperature storage and others. |
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