Effects Of Propylene And1-MCP On Post-harvest Physiological Changes And Expression Of EXP Genes Of Persimmon Fruits With Different Storability

Persimmon fruits naturally softened easily after harvest and they were not at all storableand transportable. Persimmon fruits had different storability among different varieties.Different storage properties of persimmon cultivars,‘Fuping Jianshi’ and ‘Ganmaokui’ wereused as the study material. The fruits were harvested when they were medium well-MW.Fruits were treated with propylene and1-methylcyclopropene(1-MCP). The firmness,respiration rate, ethylene release rate, the activity of ACS and ACO were measured andanalyzed every3days. This study aimed to investigate the effects of propylene and1-MCP onpostharvest physiological changes of persimmon fruits with different storability and toimprove the storge quality of different varieties of persimmon fruits.In order to furtherexplore the function of expansins (EXP) in the postharvest softening progress of persimmonfruits, real-time fluorescent quantitative PCR technology was used to detect the relativeexpression level of EXP genes in persimmon fruits. The main results were as follows:1.The firmness of the two varieties of persimmon fruits declined continuously during thestorage and the time of the firmness droped by2kg·cm-2of ‘Fuping Jianshi’ was earlier than‘Ganmaokui’. The peak of respiration and ethylene of ‘Fuping Jianshi’ was earlier and higherthan ‘Ganmaokui’. During storage the activities of ACS and ACO of the two varieties ofpersimmon fruits offered upgrade firstly than descending latter tendency. The activities ofthese two enzymes of ‘Fuping Jianshi’ were higher than ‘Ganmaokui’.1-MCP delayed thesoftening of persimmon fruits, but the degree of the effects on firmness of the two varietieswere similar;1-MCP reduced the respiration rate and ethylene release rate significantly anddecreased the activities of ACS and ACO of the two varieties of persimmon fruits. Propylenepromoted the softening of persimmon fruits, increased the respiration rate and the ethylenerelease, advanced respiratory and ethylene release climacteric and promoted the activities ofACS and ACO. The influences of propylene on ‘Fuping Jianshi’ were more significant.Results showed ‘Fuping Jianshi’ was more sensitive to propylene than ‘Ganmaokui’ and theconsequence of ‘Fuping Jianshi’ treated with1-MCP was more effective than ‘Ganmaokui’. 2. Accompanying with fruit ripening, the expression levels of DkEXP3(CDK-EXP3) andDkEXP4(CDK-EXP4) in control fruit increased sharply to maximum within the first9d ofstorage, followed by a steady decline until the end of storage. Treatment with propylenepromoted the expression of DkEXP3and DkEXP4, increased and advanced the peak of theirexpression; treatment with1-MCP showed a suppression of DkEXP3and DkEXP4expressionin persimmon fruit, delayed and reduced the peak intensity. The peak expression levels ofDkEXP3and DkEXP4in control fruit and1-MCP treatment fruit appeared earlier than thoseof the peak of ethylene production rate. The results indicated that EXP might play a role in theearly stage of postharvest persimmon fruit ripening and softening progress. The expression ofEXP genes is regulated by ethylene.3.The expression levels of EXP genes were different in sarcocarp, pericarp and core. Theexpression of EXP genes is tissue-specific...