菘蓝碳氮代谢与基质C/N对氮处理的动态响应

Carbon and Nitrogen Metabolism of Isatis indigotica and Dynamic Response of Matrix C/N to Nitrogen Treatment

为研究施氮后基质C/N和菘蓝(Isatis indigotica Fort.)碳氮代谢的动态变化,以河北居群的菘蓝为试验材料,播种后施用0、5、15、20 g·L^(-1)CO(NH_(2))_(2),分别记为CK、N1、N2、N3。利用重铬酸钾外加热法和碳氮分析仪测定基质及菘蓝碳、氮元素含量;实时荧光定量PCR(qRT-PCR)法测定菘蓝碳氮代谢酶基因的表达;超高效液相色谱(UPLC)法测定菘蓝指标成分含量。结果表明,菘蓝碳氮代谢对不同浓度氮营养的响应不同。随着处理时间延长,N1、N2、N3叶与根的可溶性糖含量先增加后减少,与磷酸烯醇式丙酮酸羧化酶(PEPC)基因表达量变化趋势相反,与蔗糖磷酸合成酶(SPS)活性变化趋势相似。菘蓝碳氮代谢产物与碳氮代谢关键酶的活性及基因表达量密切相关。N1靛蓝含量与硝酸还原酶(NR)基因表达量变化趋势相似,靛玉红含量与谷氨酰胺合成酶(GS)基因表达量、谷氨酸合成酶(GOGAT)活性变化趋势相似,与GOGAT基因表达量、GS活性变化趋势相反。N2靛蓝含量与NR活性变化趋势相反,与GOGAT基因表达量变化趋势相似,靛玉红含量与NR、GS基因表达量、GOGAT活性变化趋势相似。N3靛蓝、靛玉红含量与NR、GS基因表达量、GOGAT活性变化趋势相似。GS、GOGAT活性和其相应酶基因表达量的变化趋势相反。随着菘蓝的生长,基质中的碳元素含量逐渐增加,氮元素含量逐渐减少,C/N升高。菘蓝碳、氮元素含量的变化趋势与基质相反。施氮后,菘蓝叶、根中累积的氮素含量增多,基质中的氮素减少,碳元素含量的变化与氮相反。N2处理各种酶的活性及基因表达量较高,同时累积更高的活性成分。综上,15 g·L^(-1)CO(NH_(2))_(2)处理更有助于菘蓝指标成分的累积。本研究结果为菘蓝氮营养高效利用提供了理论参考。

To provide theoretical support for the effective utilization of nitrogen nutrition in I.indigotica,this research was aimed to explore the dynamic changes in substrate C/N,carbon,and nitrogen metabolism of I.indigotica after nitrogen application.I.indigotica was used as the experimental material from the province of Hebei(HB).The treatments of 0,5,15 and 20 g·L^(-1)CO(NH_(2))_(2)were named as CK,N1,N2 and N3.The content of carbon and nitrogen in the matrix and I.indigotica was determined by potassium dichromate external heating method and carbon and nitrogen analyzer,quantitative real-time PCR(qRT-PCR)was used to ascertain the expression of enzyme genes in carbon and nitrogen metabolism of I.indigotica,ultra-high-performance liquid chromatography(UPLC)was used to determine the index components of its composition.Carbon and nitrogen metabolism of I.indigotica responded differently to various nitrogen-feeding concentrations.The soluble sugar content of N1,N2,and N3 leaves and roots initially increased and then decreased after treatment,in contrast to the changing trend in phosphoenolpyruvate carboxylase(PEPC)gene expression and similarly to the changing trend in sucrose phosphate synthase(SPS)activity.The carbon and nitrogen metabolites of I.indigotica are closely related to the activity and gene expression of key enzymes involved in carbon and nitrogen metabolism.While the trend of N1 indirubin content is comparable to that of glutamine synthetase(GS)gene expression and glutamate synthetase(GOGAT)activity,opposite to that of GOGAT gene expression and GS activity,the trend of N1 indigo content is similar to that of nitrate reductase(NR)gene expression.While the trend of N2 indirubin content is comparable to that of NR,GS,andGOGATactivity,the trend of N2 indigo content is similar to that of GOGAT gene expression,but opposite to that of NR activity.The changing trend of N3 indigo and indirubin content is similar to that of NR,GS gene expression,and GOGAT activity.GS,GOGAT activity,and gene expression were all changing in opposite direction.With the growth of I.indigotica,the carbon element in the matrix gradually increased,the nitrogen element gradually decreased,and the C/N increased.The changing trend of carbon and nitrogen elements in I.indigotica was opposite to that of the substrate.After nitrogen application,the nitrogen accumulated in the leaves and roots of I.indigotica increased,while the nitrogen in the substrate decreased,the change of carbon element was opposite to that of nitrogen.The activity and gene expression of important enzymes in carbon and nitrogen metabolism were tightly correlated with the carbon and nitrogen metabolites of I.indigotica.After N2 therapy,the activity of various enzymes and gene expression increased,and more active components accumulated.The treatment with 15 g·L^(-1)CO(NH_(2))_(2)was more conducive to the accumulation of indicator components of I.indigotica.