Cucumber is an economically important horticultural crop that is highly dependent on nitrogen fertilizer. Nitrate is the main nitrogen source for cucumber; however, the effects of nitrogen signaling on the early-stage growth of cucumber seedlings and the related regulatory mechanisms are still unclear. To compare seedling growth status at different nitrate levels, we performed a growth experiment using cucumber seedlings that had nearly exhausted their nitrogen reserves under nitrogen deficiency conditions (NO3−-N/NH4+-N = 0 in MS medium). Using qPCR and in situ RNA hybridization localization of candidate CsNPF genes, we found that short-term nitrogen deficiency promoted changes in root vascular bundle morphology and xylem growth in cucumber seedlings, thereby enhancing their growth potential. Among the candidate genes, CsNPF7.2, a gene located in the vascular cambium was found to be induced by short-term nitrogen deficiency. Considering the abundance of vasculature development marker genes, we speculated that the function of CsNPF7.2 might relate to the development of vascular bundles in plants suffering from nitrogen stress. The objective of our study was to investigate the growth changes in cucumber seedlings in response to different nitrogen levels, and to examine the mRNA accumulation and expression patterns of nitrate transporter CsNPF genes, so that critical genes can be identified to improve nitrogen use efficiency in cucumber cultivation. The results of this study provides a novel theoretical basis for optimizing cultivation, regulating rational fertilization levels, and improving nitrogen use efficiency in production. In addition, our study also provides new avenues for the further study of the function of CsNPF7.2 on regulating vasculature development in response to nitrogen stress.