| Kiwifruit soft and juicy,sweet and sour delicious,because of the rich vitamin C known as the "king of vitamin C",deeply loved by consumers.The fruits of kiwifruit are typical of respiratory jump type and often decomposed by anthracnose and mucor soft rot after harvest.However,there are few studies on the control of anthracnose and mucor soft rot of kiwifruit.This paper will mainly explore the effect of salicylic acid and calcium chloride on the control of anthrax and Mucor.The research results are as follows:(1)In this study,salicylic acid and calcium chloride were used to treat Colletotrichum fructicola and Mucor piriformis,respectively,to evaluate the bacteriostatic effect by counting the colony diameter,bacteriostatic rate and spore germination rate.The results showed that the concentration of salicylic acid and calcium chloride was negatively correlated with colony diameter and spore germination rate.The higher the concentration of salicylic acid and calcium chloride,the stronger its bacteriostatic ability.Anthrax was more sensitive to salicylic acid,mucor was more sensitive to calcium chloride.Salicylic acid(0.3 and 0.6 g/L)and calcium chloride(5% and 9%)can inhibit the growth of anthrax and mucor.(2)Kiwifruit was treated with 0.3 g/L and 0.6 g/L salicylic acid,and 5% and 9% calcium chloride,respectively.The fruit lesion diameter,the activities of catalase(CAT),superoxide dismutase(SOD),peroxidase(POD),polyphenol oxidase(PPO),phenylalanine ammoniase(PAL)and the contents of total phenol and malondialdehyde(MDA)were determined to verify the effect of salicylic acid and calcium chloride on the control of anthracnose and Mucor soft rot.The results showed that the anthrax spot of kiwifruit treated with 0.3 g/L salicylic acid and 9% calcium chloride was significantly smaller than that of control group,and the enzyme activities of CAT,POD,PPO,PAL and total phenol content of kiwifruit were increased,and the content of malondialdehyde was decreased.After 0.3 g/L salicylic acid and 9% calcium chloride treatment,the mucormycosis of kiwifruit was significantly smaller than that of control group,and the CAT,PPO,PAL enzyme activities and total phenol content of kiwifruit were increased,while the malondialdehyde content was decreased.(3)In order to investigate the effects of 0.3 g/L salicylic acid and 9% calcium chloride treatment on the expression of resistance genes PR-1 and PR-5 in kiwifruit,q PCR analysis was performed on fruits at different storage periods.The expression of PR-1 in kiwifruit inoculated with anthrax spores treated with 0.3 g/L salicylic acid was significantly higher than that of the control at day 1,5 and 7,while the expression of PR-5 was significantly higher than that of the control at day 1,3 and 7.The expression levels of PR-1 and PR-5 of anthrax spores inoculated on 9% calcium chloride treated kiwifruit were significantly higher than those of control on the 1st and 5th day of storage.The expression level of PR-1was significantly higher than that of the control at day 1,5 and 7,and the expression level of PR-5 was significantly higher than that of the control at day 1 when the Mucor spores were inoculated on kiwifruit treated with 0.3 g/L salicylic acid.The expression of PR-1 in kiwifruit inoculated with Mucor spores treated with 9% calcium chloride was significantly higher than that of control at the 1st,3rd and 5th days of storage,and the expression of PR-5 was significantly higher than that of control at the 1st day of storage.According to the above results,0.3 g/L salicylic acid and 9% calcium chloride can promote the expression of resistance genes PR-1 and PR-5 in kiwifruit,respectively.In this study,different concentrations of salicylic acid and calcium chloride were used to treat kiwifruit.By statistical analysis of the diameter of the spot,measuring various physiological indexes and analyzing the expression of resistance genes,the control effect of the two on anthrax and mucor soft rot was explored.The results showed that both salicylic acid and calcium chloride treatment could improve the disease resistance of kiwifruit and inhibit the growth of anthrax and mucor.It laid the foundation for the control of postharvest anthracnose and mucor soft rot of kiwifruit. |
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