Fig 1. Decreased NO3- concentration in the clca-2 mutant accelerated nitrogen (N) assimilation, resulting in higher N use efficiency (NUE).
Plants grown hydroponically were sampled for further analysis at the seedling stage. Conditions for hydroponics culture and characteristics of Arabidopsis thalina (A. thaliana) are defined in the “Methods”. The wild-type Wassilewskija (Ws) plants were used as the control for the CLC null mutant (clca-2). At the seedling stage, plants were sampled for NO3- assays (A), and the activities of nitrate reductase (NR) (B) and glutamine synthetase (GS) (C) were shown in Ws and clca-2. NUE values were calculated based on total biomass (shoot and root) per total N uptake, and the differences in NUE of Ws and clca-2 were shown in D. Bars indicate standard deviations (SD) of four biological replicates. The asterisks denote significant differences at P < 0.05.