The Effects Of 5-aminolevulinic Acid On Coloration And Postharvest Storage Of Litchi Chinensis Sonn.Cv Feizixiao

China was the origin country of litchi,also was the the largest litchi producer.'Feizixiao'litchi(Litchi chinensis Sonn.cv.Feizixiao)was popular globally for its delicious taste.Growers usually picked immature 'Feizixiao' litchi when the epicarp was still green instead of red,which severely affected its market value.In addition,red color deterioration and pericarp browning were the main postharvest problems of litchi fruit during storage,transportation and sale process,and significantly reduced the commercial value of litchi fruit.This study aimed to investigate the influence of 5-Aininolevulinic acid(5-ALA)and thidiazuron(TDZ)on fruit coloring and postharvest storage of 'Feizixiao' litchi.The main findings as follows:1?The vitamin C content of 5-ALA-treated fruits was higher 9%-13%than that of the control fruits;The application of 5-ALA significantly increased fruit length and diameter and improved the fruit weight by 9%-17%compared with that of the control,but there was no significant effect on the titratable acid content;After treatment with exogenous 5-ALA at 80 and 100 mg·L-1,the TSS content and edible rate peaked at 16 d,which were delayed by 5 d compared to those of the control.2.The application of 5-ALA significantly increased the anthocyanin content at harvest(after treatment 20d)and had no significant effect on the total chlorophyll content of litchi pericarp.Redundancy analysis showed that 5-ALA improved the skin color of 'Feizixiao'litchi by promoting anthocyanin accumulation,but not chlorophyll degradation,in the pericarp during the time of harvest.Membership function diagram of 'Feizixiao' litchi at harvest indicated that treatment with 100 mg·L-1 5-ALA was found to be the most efficient to yield.3.Preharvest application of 5-ALA and TDZ significantly reduced lipid peroxidation,relative leakage rate and inhibited activities of PPO on days 6 after harvest,had no significantly effect on browning index,disease index and physiological loss in weight(PLW)on days 0,3 and 6.Preharvest application of TDZ had on significantly effect on the activities of CAT?SOD?APX,however,5-ALA maintianed activities of antioxidant enzymes(CAT,SOD,APX)at a higher level,respectively higher 20.92%?52.13%?27.67%than that of control on 6d.Generally,this study showed that 5-ALA significantly improved the skin color at harvest time and fruit quality by promoting the growth of fruit,delaying the degradation of soluble solids,increasing the edible rate,and shortening the interval of aril development and skin coloration.In addition,both the preharvest application of 5-ALA and TDZ were able to inhibite pericarp browning and increase the shelf life of fruits during postharvest storage and had no negative effects on postharvest storage of litchi.