Garlic (Allium sativum L.) was among the earliest cultivated crops, has been planted all over the world. Allicin and garlic polysaccharide are important active ingredients in garlic, which have been popular in medicine, health and functional food. The S fertilization has already been shown to have a strong influence on the formation of S containing secondary metabolites in crops. Along with nitrogen metabolism in the metabolic process of sulfur, so there is synergistic effect between sulfur and nitrogen. The aim of this study was to analyze the response relationship between the garlic quality and the nitrogen and sulfur interaction, and to evaluate the comprehensive quality of garlic bulbs by the method of membership function, a pot experiment was conducted by using three levels N and S applied in factorial combinations of 5, 10, 20 mmol/L and 2, 4, 8 mmol/L in vermiculite and pearlite culture. The results indicated that the main inclusion reacted differently in response to N and S levels. N or S single factor had no significant effect on content of soluble protein, VC, garlic polysaccharide, free amino acid, while S had significant effect on allicin. The influence of N, S single factor on garlic quality was far lower than that of the interaction of N and S. The quality of garlic bulbs was raised to different extents by nitrogen and sulfur fertilization, and the interaction of nitrogen and sulfur had a significant effect on the quality formation of garlic. When N concentration was 10-20 mmol/L, sulfur concentration had significant effect on allicin content of garlic bulbs. The content of allicin was increased significantly as the increase of S levels under 4.0 mmol/L, but decreased when the sulfur content reached at 8.0 mmol/L, which showed that high content of sulfur element could inhibit the synthesis of allicin. Content of garlic polysaccharide was promoted by increasing nitrogen or sulfur fertilization. However, it would be inhibited when the nitrogen content exceeded to 10.0 mmol/L or the sulfur content reached at 8.0 mmol/L. Content of polysaccharide was the highest of 40.50% with the N 4.0 mmlol/L and S 10 mmol/L. Garlic quality of treatment with N 20.0 mmol/L and S 4.0 mmol/L was optimal, and the membership function value was 0.81, while the control group was the lowest. The results of comprehensive analysis showed that nitrogen and sulfur fertilization significantly influenced quality of garlic bulbs, N 20.0 mmol/Land S 4.0 mmol/L was optimal to improve garlic quality, and there was a significant interaction between nitrogen and sulfur element. The study would be helpful in providing practical theory guidance for fertilization on garlic.%试验采用蛭石-珍珠岩盆栽方式,研究了不同浓度氮(5、10、20 mmol/L,记作N1、N2、N3)、硫(2、4、8 mmol/L,记作S1、S2、S3)配施条件对大蒜鳞茎品质的影响,并采用隶属函数法对大蒜品质进行综合评价,分析鳞茎品质与氮硫互作水平的响应关系.试验结果表明,氮素、硫素对大蒜主要营养成分含量影响不尽相同,氮硫配施能够不同程度提高大蒜鳞茎中可溶性蛋白、VC、大蒜多糖、游离氨基酸的含量,且氮、硫单一因素对大蒜鳞茎品质影响远低于元素间交互作用.但在氮素适宜水平下(10~20 mmol/L),硫素水平对大蒜鳞茎中大蒜辣素含量有显著影响,提高硫浓度能够显著增加大蒜辣素含量,而在硫素浓度过高时(8 mmol/L)则明显抑制该物质合成.隶属函数法综合评价以N3S2处理组大蒜鳞茎品质最优,隶属函数值为0.81,对照组(CK)最差.综合分析可见,无机基质栽培条件下氮硫配施显著影响大蒜鳞茎品质,氮素浓度20 mmol/L(N3)、硫素浓度4 mmol/L(S2)时最利于大蒜鳞茎品质的提升,为大蒜无机基质栽培最佳氮、硫配施水平,且两元素配施存在明显的互作效应.该结论为大蒜栽培氮、硫元素合理配施提供试验指导.
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