Fig. 2: Effects of exogenous application and endogenous induction of melatonin on the ACC content and ethylene production.

a–c Changes in the content of melatonin a and ACC b and ethylene production rate c in ‘Crimson seedless’ vine roots and leaves at 3 days after 50 µM melatonin treatment. d PCR identification of ASMT-overexpressing tobacco plants using DNA templates and specific primers from 35S and ASMT. e ASMT expression in tobacco leaves of wild-type (WT) and transgenic lines. f–h Changes in melatonin f, ACC content g and ethylene production rate h in leaves and roots of WT and transgenic tobacco plants. The numbers represent 5 different transgenic lines of tobacco plants in d. ud, undetectable; WT, wild type; M, DNA marker; Con, control; ASMT, acetylserotonin methyltransferase. Values represent the means ± SD of three replicates. ** highly significant difference, P < 0.01. Values indicated by the same lowercase letters are not significant at P < 0.05. A one-way analysis of variance (ANOVA) followed by a nonparametric Kruskal–Wallis test was employed