Abstract:

Different concentrations of melatonin were applied to the tomato cultivar ‘Jinpeng NO. 1’ under salt stress with
150 mmol/L NaCl to investigate the effect of melatonin on fruit yield, quality and volatile compounds. Results indicated
that the application of melatonin at 50 and 100 μmol/L significantly improved soluble sugar, soluble solids, VC, and betacarotene
contents of tomato fruits. The treatments also significantly reduced organic acid and nitrate contents in fruits and
improved fruit quality. Headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass
spectrometry (GC-MS) was used to analyze the composition and contents of volatile substances in tomatoes from different
treatment groups. The results showed that salt stress improved the content of total volatile substances in fruits, which was
further increased by the application of melatonin at various concentrations. Among five concentration treatments, melatonin
was the most effective at 50 μmol/L. Taken together, the application of melatonin at 50–100 μmol/L to tomato under salt
stress can improve fruit quality and enhance fruit aroma.

Key words: salt stress, melatonin, tomato, quality, volatile compounds