Effect Of Salicylic Acid On Loquat Fruits Quality And Senescence

Loquat is a fruit whose output in China is premier of the world.Owing to abundant nutrition, delicious taste and high quality as well as appearance,the loquat industry has high potential for develop. Salicylic acid(SA),a simple hydroxybenzene,is widely distributed in the plants.The effects of SA on many physiological metabolisms in plant have been paid more and more attention.One after another,the ability of SA to improve the endurance of plants in abiotic stress,such as disease,salt,cold,hot and drought has been found.In recent years,SA is regarded as a endogenesis signal molecule or new phytohormone.It plays many kinds of physiological roles inside the plants.Effect of SA on quality and senescence in loquat fruits was not very clear.In this paper we tried to study the effects of exogenous SA pretreatment on the fruit quality,membrane lipid peroxidation and protected enzyme system,which primarily posted the effect and mechanism of exogenous SA to delay the senescence in cold-stored loquat fruits.Using Eriobotrya japonica Lindl.CV.wuxin as test material,the experiment was carried out to study the effects of different dose(0.1 g/L,0.3 g/L,0.5 g/L)of salicylic acid on fruit quality and senescence of cold-stored(4～8℃)loquat fruits.The results were as following:1.Treatment with different concentrations of salicylic acid(SA)solution for 20 minutes significantly delayed the trauma of some physiological or biochemical index.0.1 g/L SA treatment inhibited the rotten of fruits,decreased the weight loss ration of fruits,and maintained higher titratable acid and Vc content of fruits.It also inhibite the decline of the TSS content of fruits in the late of the cold storage period,and then kept good quality of fruits,prolonged the storage period of fruits,compared to control.2.Treatment with three concentrations(0.1 g/L,0.3 g/and 0.5 g/L)of salicylic acid(SA)solution for 20 minutes could reduce the accumulation of molondialdehyde(MDA)contents of Loquat fruits by 21.74%,14.78%,3.47%than the control group,respectively.0.3 g/L and 0.5 g/L SA treatments were helpful for maintaining the flesh firmness of fruits. 3.The study of antioxidant enzymes showed that the activities of superoxide dismutase(SOD)and catalase(CAT)in Loquat fruits were increased,inhibited the increase in peroxidase(POD)activity,when the loquat fruits were soaked in different concentrations of salicylic acid(SA)solution for 20 minutes and then were stored in 4～8℃.SA may maintain the balance betweenthe formation and detoxification of active oxygen species,inhibit their accumulation and may increase the activities of cell defense enzymes, thus delay the senescence process in cold-stored loquat fruits.All of the results concluded that the best concentration of salicylic acid was 0.1g/L.