5-Aminolevulinic acid affects fruit coloration, growth, and nutrition quality of Litchi chinensis Sonn. cv. Feizixiao in Hainan, tropical China

Litchi chinensis Sonn. cv. 'Feizixiao' is commonly cultivated in orchards in Hainan Island of tropical China; however, its commodity value was reduced due to the non-synchronized pericarp coloration and low aril nutritional quality. 5-Aminolevulinic acid (5-ALA), a key precursor in the biosynthesis of porphyrin compounds, is known to bean effective plant growth regulator for improving fruit coloration and nutritive quality. In this study, 5-ALA solution was exogenously sprayed at concentrations of 80, 100, 120, 140, and 160 Mg L-1 on the fruit peel of 'Feizixiao' litchi at 45 days after full bloom. Fruit growth, coloration and nutritive quality were determined. The treatment with 5-ALA at 80 mg L-1 maintained the vitamin C content of the aril at a higher level than that of the control. The application of 5-ALA significantly increased fruit length and diameter compared with that of the control, but there was no significant effect on the titratable acid content. At 20 days after 5-ALA treatment, anthocyanin contents of the pericarp were significantly higher and the hue angle (h degrees) was significantly lower than those of the control. 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. 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 developement and skin coloration. (C) 2015 Elsevier B.V. All rights reserved.