叶面喷施丙三醇对烟叶碳氮代谢及硝酸盐积累的影响

Effect of foliar application of glycerol on carbon and nitrogen metabolism and nitrate accumulation in tobacco leaves

【目的】探索丙三醇对白肋烟碳氮代谢及其硝酸盐积累的调控机理,建立新的白肋烟增效减害调控技术。【方法】以白肋烟品种TN90和TN86为材料,设置不同丙三醇浓度试验,并在确定丙三醇最佳适宜浓度的基础上,设置高氮和低氮两个处理,研究丙三醇对烟叶生物量积累、氮代谢关键酶活性、主要碳氮化合物含量及相关基因表达情况的影响。【结果】1)在高氮和低氮水平下,喷施丙三醇15 d后,烟叶生物量分别增加10.20%和13.36%,氮素积累量和氮素利用效率分别增加10.21%、3.15%、6.81%和3.11%,烟叶总糖和还原糖含量分别升高了25.15%、32.84%、47.76%和44.57%,但7 d后烟叶硝酸盐含量下降了53.22%和59.67%;2)低氮水平下喷施丙三醇烟叶色素、可溶性蛋白质和两糖含量与高氮条件下不喷施丙三醇结果相近;3)基因表达分析表明,喷施丙三醇显著促进了光反应途径、碳固定途径、蔗糖合成和氮代谢途径关键基因的表达,与对照相比,基因CP12-2、PPC16和NPF7.3的表达量增加0.5倍多。【结论】丙三醇能够提高烟叶碳氮代谢能力和氮素利用效率,提高烟叶碳水化合物含量和降低烟叶硝酸盐积累量,减氮配合喷施丙三醇是降低烟叶硝酸盐积累的有效途径。

In order to find out the regulation mechanism of glycerol on carbon and nitrogen metabolism and nitrate accumulation in burley tobacco and establish a new regulation technology of increasing the effect and reducing harm,TN90 and TN86 burley tobacco were used as research objects which were grown under different concentrations of glycerol.On the basis of determining the optimal concentration of glycerol,two treatments of high nitrogen and low nitrogen were set to study the effects of glycerol on biomass accumulation,activity of key enzymes in nitrogen metabolism,content of major carbon and nitrogen compounds and the expression of related genes in tobacco leaves.Results showed that under the condition of high nitrogen and low nitrogen,the biomass and nitrogen accumulation of tobacco leaves and nitrogen utilization efficiency increased by 10.20%,13.36%,10.21%,3.15%,6.81%and 3.11%,and content of total sugar and reducing sugar increased by 25.15%,32.84%,47.76%and 44.57%,respectively.Meanwhile,content of pigment,soluble protein,total sugar and reducing sugar in tobacco leaves with foliar application of glycerol at low nitrogen level was similar to those without foliar application of glycerol under the condition of high nitrogen application.Analysis of further gene expression showed that glycerol can significantly promote the expression of key genes in the light reaction pathway,carbon fixation pathway,sucrose synthesis and nitrogen metabolism pathway.Compared with control group,the expression levels of CP12-2,PPC16 and NPF7.3 increased by more than 0.5 times.Glycerol can improve carbon and nitrogen metabolism and nitrogen utilization efficiency in tobacco leaves,which lays a foundation for increasing content of carbohydrate and reducing the nitrate accumulation in tobacco leaves.Reducing nitrogen treatment combined with foliar application of glycerol may be an effective method to reduce nitrate accumulation in burley tobacco.