酶抑制剂对烤烟成熟期氮代谢及烤后烟叶品质的影响

摘要

In order to effectively control the nitrogen metabolism in overgrown tobacco plants at mature stage and promote the quality of flue-cured leaves, field trials were conducted between 2013-2014 to investigate the effects of an enzyme inhibitor, 4-[hydroxyl(methyl)phosphinoyl]-DL-homoalanine (glufosinate). The activities of nitrate reductase (NR) and glutamine synthetase (GS), key enzymes for nitrogen metabolism, and the chemical components in tobacco leaves were determined. In addition, sensory quality of treated flue-cured tobacco leaves for cigarettes was panel tested. The results showed that spraying the enzyme inhibitor at different concentrations at mature stage effectively decreased NR and GS activities in tobacco leaves, and the concentration of the enzyme inhibitor significantly negatively correlated to the NR and GS activities. The NR and GS activities declined quickly in the treated leaves and good field performance was achieved at the enzyme inhibitor concentrations between 10 and 15 mg/L. After spraying at the appropriate concentrations at mature stage, the contents of protein, nicotine and total nitrogen decreased, while those of reducing sugar and total sugar increased in the flue-cured leaves. The leaf chemical composition was more harmonious, the pigment content was reduced and the contents of neutral aroma components increased by 25.04%-42.76%. These have resulted in an increased score of sensory by 7.22%-10.43% . Considering cost and safety, 10 mg/L was recommended as a more appropriate concentration.%为了有效控制生长过旺烤烟成熟期的氮代谢、改善烤后烟叶品质，于2013—2014年烤烟成熟期喷施适宜浓度的酶抑制剂4-[羟基（甲基）膦酰基]-D/L-高丙氨酸（草胺膦），测定了烟叶的硝酸还原酶（NR）、谷氨酰胺合成酶（GS）活性和化学成分含量（质量分数），并对烤后烟叶进行了评吸鉴定。结果表明，成熟期喷施不同浓度酶抑制剂能有效降低烟叶NR和GS活性，且酶抑制剂浓度与NR、GS活性均呈显著负相关，其中10、15 mg/L浓度下叶片NR和GS活性降低较快，且叶片田间表现较好；适宜浓度酶抑制剂喷施于成熟期烟叶，烤后烟叶蛋白质、烟碱、总氮含量降低，还原糖、总糖含量（质量分数）提高，化学成分更加协调，色素含量（质量分数）降低，中性致香成分含量（质量分数）提高25.04%～42.76%，感官品质得分提高7.22%～10.43%。从成本和安全性方面综合考虑，10 mg/L更为适宜。因此，10 mg/L浓度酶抑制剂能够有效降低烤烟氮代谢关键酶（GS和NR）活性，抑制成熟期氮代谢，改善烟叶品质。