| The sweet cherry(Prunus avium L.)is a subgenus of the genus Prunus of the genus Rosaceae.The fruit is bright in color,rich in nutrition,mature early,and has High nutritional value and economic value.However,due to the fruit of sweet cherry juice thin skin,the quality of the cherry fruit decreases rapidly after harvest,seriously affects its commercial properties.Salicylic acid(SA)is a phenolic substance commonly found in plants and is involved in the regulation of many physiological processes in plants.Treatment with SA can delay the maturation and senescence of fruit,increase storage effect,and induce the improvement of plant resistance and disease resistance.SA was found to have side effects in regulating the growth and development of plants as yet.Because SAis highly efficient,low-cost,non-toxic,and has no residue,it has shown broad prospects in production and application.This article uses the sweet cherry variety 'red light' as the test material and performs the following treatments:1.Spray the salicylic acid solution on the leaves during the hard nucleus stage and the color change stage of sweet cherry,and the spraying concentration is 0,0.4,0.8,1.2 mM respectively.Determination of Changes of Main Fruit Quality and Antioxidant Activity in Sweet Cherry Fruits after Application of Salicylic Acid with Different Concentrations.2.After harvesting,the untreated fruits were soaked with 2 mM salicylic acid,and the fruits treated above were stored in a cold storage at 0?,the test included the following four treatments:control(pretreatment of clear water),treatment 1(pre-harvest 0.4 mM salicylic acid),treatment 2(pre-harvest 0.8 mM salicylic acid),treatment 3(preharvest 1.2 mM salicylic acid)Treatment 4(2 mM salicylic acid after harvest).During storage,the main quality indexes,rot,weightlessness and antioxidation of sweet cherry fruits under different treatments were measured.The main test results are as follows:1.Salicylic acid treatment can delay the increase of soluble solids,soluble sugar,titratable acid,Vc and anthocyanin content of sweet cherry fruits,thus delaying ripening and aging of fruits.The effect of 0.4mM salicylic acid treatment is most pronounced with respect to the other two treatments,On May 19,soluble solids content,soluble sugar content and titratable acid content were the lowest,which were 71.1%,84.5%and 80.3%of the control,respectively.However,the effect of retarding the increase of fruit Vitamin C content and anthocyanin content was not as good as that of 0.8 mM and 1.2 mM salicylic acid.Compared with the control,0.4mM,0.8mM and 1.2mM salicylic acid treatment reduced SOD and POD activity and increased CAT activity,Among them,0.4 mM salicylic acid had the best inhibition of SOD and POD activity,and 1.2 mM salicylic acid increased the activity of CAT best.2.During the storage of sweet cherry,pre-harvest 1.2 mM salicylic acid had the best effect on inhibiting fruit rot,delaying the decrease of titratable acid content and Vitamin C content of sweet cherry fruit and promoting the increase of anthocyanin content.Compared with the control,pre-harvest 0.4 mM and 0.8 mM salicylic acid treatment can improve the brightness of the fruit during storage,promote reddening and yellowing of the fruit,and the effect of 0.4 mM salicylic acid is better than that of 0.8 mM salicylic acid.Pre-harvest 0.4 mM salicylic acid can effectively delay fruit softening.Pre-harvest 0.8 mM concentration of salicylic acid inhibited sweet cherry's best soluble sugar content in the early storage stage.With the maturity and aging of sweet cherries,malondialdehyde and hydrogen peroxide content showed a rising trend.Pre-harvest salicylic acid treatment can delay the increase of H2O2 and malondialdehyde content during storage of sweet cherries.In the early stage of storage,Pre-harvest 0.4 mM concentration of salicylic acid inhibited H2O2 growth better.At the late stage of storage,the effect of pre-harvest 1.2 mM salicylic acid was superior to the other two groups.Pre-harvest 0.4 mM salicylic acid treatment has better effect of inhibiting the increase of malondialdehyde content.Pre-harvest 0.8 mM salicylic acid had the best effect on increasing SOD and POD activity in fruits,Treatment with pre-harvest 1.2 mM salicylic acid had the best effect on reducing CAT activity of sweet cherry fruit.In the early stage of storage,pre-harvest treatment with 1.2 mM salicylic acid before harvest can significantly increase fruit PAL activity.At the end of storage,pre-harvest 0.8 mM salicylic acid works better.Preharvest salicylic acid treatment can increase PPO activity during storage of sweet cherry,The pre-harvest 0.4 mM salicylic acid treatment had better results in the early stage,and the pre-harvest 0.8 mM salicylic acid treatment had better effects in the later stage.This shows that preharvest salicylic acid treatment can improve the resistance of sweet cherry fruit during storage and reduce fruit rot.The higher the concentration of salicylic acid,the better the effect.3.The post-harvest 2 mM salicylic acid treatment also effectively inhibited the fruit rot,and the effect was better than pre-harvest salicylic acid treatment.Post-harvest treatment with 2 mM salicylic acid can delay the decline of soluble sugar content during storage;it can effectively delay the decrease of Vitamin C content during storage of sweet cherry;delay the increase of anthocyanin content;Delay fruit softening;inhibit the increase of fruit brightness and promote reddening of fruits.However,there is no obvious effect on retarding the decrease of titratable acid contentpost-harvest 2 mM salicylic acid treatment could retard the increase of H2O2 and malondialdehyde content in sweet cherry during storage.,Increases SOD activity of sweet cherry fruits during storage.Compared with pre-harvest salicylic acid treatment,the effect of pre-storage is less obvious,and higher levels of SOD activity can be maintained during the later period of storage;Delayed the decline of CAT activity in the middle and late storage of sweet cherry;There was no obvious effect on POD activity during storage of sweet cherry,but it could significantly increase the POD activity during shelf life.Post-harvest 2 mM salicylic acid treatment could maintain high PAL activity in sweet cherry at the middle and late storage stage.It can also maintain high PAL activity of sweet cherry in the middle and late storage stage.This shows that the postharvest salicylic acid treatment can improve the storage stability of sweet cherry during storage,but some of the effects are not as good as pre-harvest group,which may be due to the unfavorable concentration. |
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