Metabolites in the shoot and root identified by LC-MS under sole nitrate, 75/25 nitrate and ammonium ratio supply, and sole ammonium supply in 12d for maize (Zhengdan 958) seedlings in hydroponic condition.

Metabolites in the shoot and root identified by LC-MS under sole nitrate, 75/25 nitrate and ammonium ratio supply, and sole ammonium supply in 12d for maize (Zhengdan 958) seedlings in hydroponic condition. Using the R (V3.3.2) XCMS package to identify peaks identification, peaks filtration, peaks alignment. In among, the main parameters are bw=5, ppm=15, peakwidth=c(10,120), mzwid=0.015, mzdiff=0.01, method=”centWave”. Obtain a data matrix including information such as“mass to charge ration, m/z”, retention time and intensity. In among, positive ion mode obtains 16068 precursor molecules and negative ion mode obtains 5259 precursor molecules for each N forms. The data was exported to excel for subsequent analysis. SCK, ST1 and ST2 indicate the metabolites in the shoot of sole nitrate supply, mixed N supply and sole ammonium supply in 12d, respectively. RCK, RT1 and RT2 indicate the metabolites in the root of sole nitrate supply, mixed N supply and sole ammonium supply in 12d, respectively.本数据集涵盖水培条件下生长12天的玉米（郑单958，Zhengdan 958）幼苗地上部与根系的代谢物，这些代谢物通过液相色谱-质谱联用（Liquid Chromatography-Mass Spectrometry, LC-MS）技术，在三种氮供应模式下完成鉴定：单一硝酸盐供应、75/25硝酸盐与铵盐比例供应、单一铵盐供应。本研究采用R（V3.3.2）软件的XCMS包完成峰识别、峰过滤与峰对齐操作，核心参数设置如下：bw=5、ppm=15、peakwidth=c(10,120)、mzwid=0.015、mzdiff=0.01、method="centWave"。最终得到包含质荷比（mass to charge ratio, m/z）、保留时间与峰强度等信息的数据矩阵，其中正离子模式下每种氮供应模式可获得16068个前体分子，负离子模式下可获得5259个前体分子。所有数据均导出至Excel表格用于后续分析。样本命名规则如下：SCK、ST1、ST2分别代表12天龄单一硝酸盐供应、混合氮供应、单一铵盐供应处理下玉米地上部的代谢物；RCK、RT1、RT2则分别对应上述三种氮处理下玉米根系的代谢物。