ZHAO Jianuo1，SHI Jianye1，WEI Haotai1，WANG Peng1，WANG Guoshuai1，LUO Shilei1，ZHANG Guobin2*
To clarify the infl uence rule of nitrogen level on the formation of appearance，nutritional and fl avor qualities of tomato at diff erent developmental stages（green ripening，color change and ripening）and in diff erent parts of the tomato（pulp and placenta）．Tomato variety 184 was used as the test material，and four nitrogen levels（CK，0 mmol·L-1 N；N1，6.3 mmol·L-1 N，70% N2；N2，9.0 mmol·L-1 N；N3，11.7 mmol·L-1 N，130% N2）were set up by substrate potting to determine the appearance，nutritional quality and fl avor quality of tomato fruits were determined at three stages of ripening（green ripening，color change and ripening）and two parts of the fruits（pulp and placenta）．The results showed that the color and light value parameters tended to increase as fruit ripening progressed，and the higher the nitrogen level at ripening，the smaller the fruit hardness and the larger the color and light value parameters．Normal nitrogen supply treatment（N2）had suitable fruit hardness，single fruit quality，and higher color and light value parameters；soluble sugar，organic acid and VC contents of tomato pulp and placenta were higher under normal nitrogen supply treatment（N2）during fruit ripening，while nitrogen reduction by 30%（N1）led to a decrease in the content of organic acid in tomato fruits，and nitrate was highest in the nitrogen addition by 30% treatment（N3）．Analysis of soluble sugar and organic acid fractions further showed that glucose，fructose，sucrose，malic acid，oxalic acid，citric acid，and tartaric acid contents were higher in tomato pulp and placenta under N2 treatment，and fruit soluble sugar and organic acid contents were the highest overall．The analysis of fl avor changes in tomato under different nitrogen levels revealed that the aromatic odor response values of tomato pulp and placenta were the highest under 30% nitrogen reduction treatment（N1），especially the increase of three aromatic substances，namely，nitrogen oxides-sensitive，aromatic components-sensitive，and aromatic components and organosulfides-sensitive，was obvious，whereas the aromatic odor response values were all lower under the normal nitrogen supply treatment（N2），and the fl avor quality was poor．Under normal nitrogen supply treatment（N2），tomato appearance and nutritional quality were better，fruit hardness was suitable，color and light value parameters，VC，soluble sugar and organic acid components were higher，but flavor quality was poorer，and under 30% nitrogen reduction treatment（N1），tomato appearance and nutritional quality were poorer，but flavor quality was improved．
