Abstract:

Boron fertilizer applications by foliar spraying (L) and nutrient solution application (W) at different levels of
boron (1.9, 3.8, and 5.7 mg/L H3BO3), respectively, were performed to investigate the effects of boron fertilizer on volatiles
of tomato (cv. “Jinpeng No.1”) fruit using boron-free nutrient solution treatment as control (CK). The composition and
content of aroma compounds were measured using solid phase microextraction coupled to gas chromatography-mass
spectrometry (SPME-GC-MS). The results showed that a total of 79 volatiles were detected in seven treatment groups of
tomato fruits, with aldehydes, esters, alcohols, hydrocarbons and ketiones being the predominant compounds. The decreasing
order of total volatile component contents was as follows: L1 > W2 > W1 > L3 > W3 > L2 > CK. Meanwhile, 14 of these
were characteristic aroma components and their total contents were in the descending order: W2 > L1 > L3 > W1 > W3 >
L2 > CK. Different application methods for the same concentration of boron and different boron levels applied in the same
way had different effects on the characteristic compounds of tomato. All 14 characteristic aroma components and 3 types
of aroma components (‘fruity aroma’, ‘green aroma’ and ‘floral aroma’) were detected in the treatment group of 3.8 mg/L
H3BO3 nutrient solution, with fruity aroma being the most predominant as well as 6-methyl-5-hepten-2-one being the biggest
contributor to the aroma, suggesting the presence of a wide range of aroma compounds in the tomato fruits. Therefore,
the application of 3.8 mg/L H3BO3 nutrient solution can result in the formation of a wide variety of aroma compounds
responsible for the strong fruity aroma in tomato.

Key words: tomato, boron fertilizer, volatiles, SPME, GC-MS