To better understand the role of melatonin in fruit ripening,
we also measured soluble sugar in melatonin-treated and
control fruits. Significantly higher levels of soluble sugar (by
10.9%) were detected in M50-fruit compared with control
sample at 17 DAT (Fig. 6C).
Both the sugars and volatiles are critical to good flavour
in tomato fruit (Klee and Giovannoni, 2011). Volatiles determine
the unique flavour of tomato, whereas the sugars are
essential for good taste. We inferred that the biosynthetic
pathway of volatiles may have been affected by melatonin
treatment. Moreover, the level of soluble sugar in M50-fruit
was higher than that of CK, indicating that melatonin may
have a critical role in tomato flavour.
Fig. 4. Melatonin has an effect on water loss in tomato fruit. CK: sample pre-treated with water; M50: sample pre-treated with 50 μmol l–1 melatonin.
(A) The rate of water loss of tomato during postharvest storage. (B) Real-time PCR analysis of aquaporin genes expression in tomato fruits at 17 d after
treatment. Vertical bars at each time point represent the LSD when significant at P=0.05.
Downloaded from http://jxb.oxfordjournals.org/ by guest on October 21, 2014