成熟期氮素调亏程度对烤烟叶片生长和化学成分含量的影响

为实现烤烟氮素动态的精准供应,采用套盆设计,在基质培养条件下,通过改变烤烟打顶后的营养液供应来调控烤烟生长后期的氮素营养,探索成熟期不同氮素调亏程度对上部烟叶生长、化学成分含量及感官质量的影响。结果表明,随着氮素调亏程度的增加,上部叶叶面积、单叶质量呈降低趋势,烟叶含氮化合物含量降低,且在打顶后总氮含量下降幅度增大,烟碱含量上升幅度减小。烤后烟叶烟碱、总氮和蛋白质含量随调亏程度增加呈降低趋势,还原糖含量呈相反的变化。以氮素调亏75%和50%的处理烟叶长势正常,叶面积适宜,叶片成熟落黄良好,上部叶的糖碱比为7.93,中部叶的糖碱比为7.89,烤烟化学成分较协调,石油醚提取物含量达到10.22%,感官质量最好。氮素调亏程度过高时(100%调亏),烟叶生长受到抑制,烟叶早衰,糖碱比高,石油醚提取物含量低,不利于产、质量的形成。不进行氮素调亏或调亏程度过低时(0和25%调亏),烟叶贪青晚熟,含氮化合物累积量大,化学成分不协调,感官质量较差。综合分析,成熟期氮素供应减少至打顶前的1/4到1/2,有利于优质烟叶的形成和浓香型风格特色的彰显。

Effect of Nitrogen Deficiency Degree at Maturing Stage on Leaf Growth and Contents of Chemical Compounds in Cured Leaves of Flue-cured Tobacco

Pot experiments were conducted to investigate the effect of nitrogen applying amount after topping on leaf growth and contents of chemical components and sensory quality.Five nitrogen applying amounts were used representing different nitrogen deficiency levels.The results showed that as the increase of nitrogen deficiency from 0 to 100% after topping,the leaf area and fresh weight decreased,so was the nitrogen-containing compounds.And the decreasing range became greater for total nitrogen content during maturing stage,while the increasing range for nicotine content became smaller with the increase of nitrogen deficiency.The contents of nicotine,total nitrogen and protein in flue-cured leaves decreased with increased nitrogen deficiency;while the changing trend for content of reducing sugar was opposite.When nitrogen applying amount after topping decreased to 1/4 to 1/2 of the nitrogen amount before topping,the leaf grew normally with adequate leaf area and decent yellowing at the right time.The contents of chemical compounds in cured leaves were ideal with sugar nicotine ratio of 7.93 for upper leaves and 7.89 for middle leaves,and the petroleum ether extract content was at higher level of 10.22%,and it gave rise to best sensory quality.For the treatment with nitrogen totally removed from the solution,the upper position leaf growth was inhibited resulting in too early ripening and higher sugar/nicotine ratio and lower petroleum ether extract content.For the treatment with less degree of nitrogen deficiency and the no-nitrogen deficiency control,the leaf maturing were delayed,giving rise to flue-cured leaves with high contents of nitrogen-containing compounds after flue-curing and less coordinating ratio and with less desirable sensory quality.