Abstract:To evaluate the potential for exogenous L-glutamic acid (L-Glu) to improve the coloration,growth and nutrient quality of litchi fruit,we sprayed L-Glu to the pericarp of the ‘Feizixiao’ cultivar at concentrations of 0,1.10,1.30,1.50,1.70,or 1.90 g/L,45 d after full bloom in 2014.The results showed that:(1)each concentration of L-glutamate had no significant effect on litchi pericarp chlorophyll content in harvest period (20 days post-treatment),however,the anthocyanin content of treatments with 1.30-1.90 g/L L-glutamic acid was significantly increased more than 92% than that of control harvest;In the harvest period,fruit surface color parameters a* value treated with 1.10-1.30 g/L L-glutamic were significantly higher than that of control.The hue angle (h° values),brightness (L*),color saturation (C values) were significantly lower than that of control.(2)Compared with the control,treatment with 1.10 g/L L-glutamate made litchi fruit weight significantly increased by 30%,a significant increase in length by 4% and diameter by 6% at harvest;while,the fruit weight,length and diameter of 1.90 g/L L-glutamate treatment were decreased by 1%-2%.(3)L-Glu treatment had no significant effect on titratable acid content in litchi fruit;however,total soluble solids content peaked at 16 d after the application of L-Glu at 1.10,1.30 or 1.70 g/L;this represents a 5 d delay compared to the soluble solids content peak of the control;the vitamin C content of 1.30 g/L L-Glu-treated fruits was 15% higher than that of control fruits,enhancing the nutritional quality of litchi.Thus,the appropriate concentration of exogenous L-glutamic acid treatment can significantly promote fruit growth and coloration of ‘Feizixiao’ litchi and effectively improve the nutritional quality in pulp,but high concentrations of L- glutamic acid (1.90 g/L) treatment showed inhibition on the growth of litchi.Therefore,the results indicate that 1.30 g/L L-Glu may be the optimum treatment concentration to improve fruit coloration,growth,and nutrient levels in ‘Feizixiao’ litchi.