Comprehensive evaluation of nitrogen use efficiency of different Lycium barbarum L. cultivars under nitrogen stress

Nitrogen (N) deficiency is a common problem for Lycium barbarum L. (goji) production in arid and semi-arid areas of northwestern of China. The development of new nitrogen-efficient goji cultivars under low nitrogen conditions is an important way to solve this problem. In the present study, morphological and nutrient-based parameters of Ningqi 1 (A), 1402 (B), Ningqi 7 (C), 1401 (D), and Ning1Y (E) were comprehensively evaluated under different nitrogen levels in the greenhouse. Finally, we concluded that Ningqi 1 (A) was high and Ning1Y (E) was low in nitrogen use efficiency under nitrogen stress. Difference of glutamate synthase activity in the root may be the reason for the difference in nitrogen use efficiency between Ningqi 1 (A) and Ning1Y (E). This work provides a reliable and comprehensive method to assess nitrogen utilization under low nitrogen conditions in goji and reveals possible physiological difference mechanisms.