Expression profiles of some citrulline metabolic genes during drought stress.

D1RPM-D4RMP indicate gene expression reads per millions for each day. ↑ and ↓ indicate the significant up-regulation and down-regulation of each gene at each time point.D1RPM-D4RMP 代表各天数对应的基因表达每百万读段数（reads per million, RPM）；箭头↑与↓分别表示各基因在对应时间点的显著上调与显著下调。