Abstract: In order to explore the optimal nitrogen application amount and its physiological functions on promoting high yield and high quality of composite sand cultured tomatoes, tomato variety of ‘Maofen 812’ was used as the experimental material, five nitrogen application treatments with 0 (N0), 143 (N1), 285 (N2), 428 (N3) and 571(N4) kg·hm-2  were set up. The effects of different nitrogen application treatments on the activities of nitrate reductase (NR) and glutamine synthase (GS) in tomato leaves, as well the fruit quality and yield of tomato were analyzed. The results showed that appropriate amount of nitrogen fertilizer was helpful to increase the activities of nitrogen metabolism enzymes in tomato leaves, thus improve fruit quality and yield. Compared with N0 treatment, the NR and GS activities of N3 treatment were increased by 42.79% and 182.93%, respectively. The vitamin C content, soluble protein content, soluble sugar content, soluble solids content and yield of N3 were increased by 70.90%, 6667%, 25.00%, 27.25% and 58.38% than those of N0 treatment, respectively. Principal component analysis, membership function method and comprehensive evaluation showed that the comprehensive ranking of different treatments was N3 > N4 > N2 > N1 > N0. Therefore, 428 kg·hm-2 was recommended as the fertilization standard for the cultivation of compound sand-cultured tomatoes, which provided theoretical basis for nitrogen fertilizer management of compound sand culture tomato.

Key words: nitrogen application rate, compound sand culture tomato, nitrogen metabolism enzyme activity, fruit quality, yield, comprehensive evaluation

摘要： 为探究复合沙培番茄最佳施氮量及其促高产和高品质的生理机能，以‘毛粉812’番茄为试验材料，设置0（N0）、143（N1）、285（N2）、428（N3）、571（N4） kg·hm^-2共5个施氮水平，分析施氮量对番茄叶片硝酸还原酶（nitrate reductase，NR）和谷氨酰胺合成酶（glutamine synthetase，GS）活性及果实品质和产量的影响。结果显示，适量施用氮肥有助于提高番茄叶片氮代谢酶活性，进而改善果实品质，提高产量。N3处理的 NR和GS活性较N0处理分别提高了42.79%和182.93%；N3处理果实中维生素C、可溶性蛋白、可溶性糖、可溶性固形物含量和产量较N0分别提高了70.90%、66.67%、25.00%、27.25%和58.38%。主成分分析、隶属函数法和综合评价得出不同处理的综合排名为N3＞N4＞N2＞N1＞N0。因此，推荐428 kg·hm-2为复合沙培番茄种植的施肥标准，为复合沙培番茄的氮肥管理提供理论依据。

关键词: 施氮量, 复合沙培番茄, 氮代谢酶活性, 果实品质, 产量, 综合评价