钨酸钠对成熟期烤烟碳氮代谢、硝酸盐含量及烟叶品质的影响

Effects of Na_2WO_4 on carbon and nitrogen metabolism at mature stage, nitrate content and tobacco quality of flue-cured tobacco leaves

本文采用田间试验,对打顶后生长过旺的烟株喷施不同浓度钨酸钠,研究其对烤烟碳氮代谢酶活性、硝酸盐、亚硝酸盐含量以及烟叶化学成分的影响。结果发现,钨酸钠处理烟株的蔗糖转化酶活性表现为先降低后略微升高的趋势,淀粉酶活性整体表现出先下降后上升又略有下降的趋势,其中对照烟叶的酶活性显著小于处理烟株。硝酸还原酶的活性表现为先升高后降低,钨酸钠处理烟株的硝酸还原酶活性显著下降。说明打顶后对生长过旺的烟株喷施钨酸钠在一定程度上减弱了烟株的氮代谢,减少了打顶后对氮素的持续利用,促进烟叶成熟落黄。喷施0.5和1.0 mmol·L^(-1)钨酸钠能显著降低烤后烟叶的硝酸盐含量,而喷施1.0和1.5 mmol·L^(-1)钨酸钠能显著降低亚硝酸盐的含量。整体来看,喷施钨酸钠对上部叶的影响大于中部叶,其中喷施1.0 mmol·L^(-1)钨酸钠的上部叶硝酸盐和亚硝酸盐含量的下降幅度最大,分别达到31.73%和20.23%。同时,施用钨酸钠增加了烤后烟叶钾含量,降低了氯和烟碱的含量,烟叶化学成分协调。综合看来,以喷施1.0mmol·L^(-1)的钨酸钠效果较好。

The field experiment was conducted to study the effects of Na_2WO_4 with different concentrations on the activities of carbon and nitrogen metabolism, the contents of nitrate and nitrite, and chemical composition of leaves in overgrown tobacco after topping. The results showed that the invertase activity showed a trend of decreasing at first and then slightly higher, and the activity of amylase showed the trend of decrease firstly, then rise, and then decrease slightly under Na_2WO_4 treatments. The enzyme activities of the control leaves were always significantly lower than those of the treated tobacco. The activity of nitrate reductase increased firstly and then decreased, and the activity of nitrate reductase in tobacco plants treated with Na_2WO_4 was significantly decreased. This suggested that spaying Na_2WO_4 on overgrown tobacco after topping, to a certain extent, weakened the nitrogen metabolism of tobacco plants, sustainable utilization of nitrogen decreased after topping, and promote ripening. The treatments of 0.5 and 1.0 mmol·L-1 Na_2WO_4 could significantly reduce the content of nitrate in flue-cured tobacco leaves, and spaying 1.0 and 1.5 mmol·L-1 Na_2WO_4 could significantly reduce the content of nitrite. On the whole, the effect of Na_2WO_4 on the upper leaves was greater than that on the middle leaves. The decrease rate of nitrite and nitrate in the upper leaves were 31.73% and 20.23% respectively, under the treatment of 1.0 mmol·L-1 Na_2WO_4. Application of Na_2WO_4 increased the potassium content, decreased chlorine and nicotine contents in flue-cured tobacco, and coordinated the chemical components of tobacco leaves. Generally speaking, the effect of spraying 1.0 mmol·L-1 Na_2WO_4 was better.