| As one of the most widely grown fruits and vegetables in the world,tomato is popular with people for its delicious taste and nutrition value.Because tomato is a mature fruit,and the skin is fragile,easily damaged and infected by mold,it causes difficulties in transportation and storage.Therefore,post-harvest tomatoes storage and preservation,postharvest disease prevention and control are also a hot spot that people are committed to research.In this study,a series of experiments on novel fruits and vegetables preservatives 1-MCP and citral were conducted to study their preservation and antibacterial effect,and their antifungal mechanism to Botrytis cinerea,which is one of main diseases of postharvest tomato.By measuring the quality of tomato fruit and related enzyme activity to study the effect of preservation and antifungal effect,the growth of Botrytis cinerea under the treatment of antibacterial agents was studied in depth to investigate the antibacterial mechanism.The results are as follows:In vivo experiment,the combined treatment of 1 ?L/L 1-MCP and 4 kJ/m2 UV-C irradiation were used to preserve fresh tomatoes after harvest and maintained good tomato quality(water loss,hardness,color index,TSS,pH And Vc content),the softening-related enzyme activity(PG and Cx)in tomato fruit was induced to decrease,the antioxidant enzyme activity(CAT and POD)in tomato fruit was induced to increase,higher sugar content was maintained.When the two preservation methods are combined,the preservation effect is better than that of the respective treatments.In vitro experiment,citral and(E)-2-hexenal have certain inhibitory effects on the gray mold.In the preliminary antifungal experiment,the minimum inhibitory concentration(MIC)is ?L/L,and the concentration(MFC)was 300 ?L/L when citral is used to treat grey mold.In comparison experiments,the minimum inhibitory concentration(MIC)of(E)-2-hexenal was 500 ?L/L,and the minimum bactericidal concentration(MFC)was 1000 ?L/L.With the increase of antifungal agent concentration,its antifungal effect is stronger,and the antifungal effect of citral on Botrytis cinerea is better than that of(E)-2-hexenal.In this experiment,the extracellular conductivity,extracellular pH,leakage of intracellular lysate,and leakage of K+ were measured under the inhibitory effect of bacteriostatic agents.The citral was used to treat the spores of Botrytis cinerea,the antioxidative enzyme activity of the fungal spores increased first and then decreased.The spores showed a red fluorescence under a fluorescence microscope,indicating that the spores'antioxidant system was destroyed.Combined with scanning electron microscopy observation,it was found that the bacteriostatic agent may cause damage to the cell structure,and the cell membrane selection permeability is destroyed,which leads to a large amount of leakage of intracellular lysate and inhibits the growth of fungi.In the entity antifungal experiment:1xMFC citral was used as a bacteriostatic agent,and the other antifungal drug thiabendazole was used as a positive control.The experimental results showed that tomato fruits in control completely rotted after the 12th day of inoculation with Botrytis cinerea,and the rot ratios of the citral-treated group,the 1-MCP-treated group,the thiabendazole-treated group,and the citral?1-MCP-mixed group were respectively 82.6%,88.56%,56.68%and 45.7%.The decay rate of the mixed treatment group was greatly reduced.For the fruit quality,there was no major change in the treatment groups.The combined treatment maimtained high hardness,TSS and Vc content,and reduced the water loss rate.The citral+ 1-MCP treatment of tomato fruits increased the activities of antioxidant enzymes CAT and POD,their peaks were advanced by 3 days,and the maximum value was also increased.In addition,the mixed treatment group induced the increase of total phenols and flavonoids in tomato fruits.The content,in turn,increases the antioxidant capacity of tomato fruits and ultimately leads to an increase in tomato disease resistance. |
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