Fig. 3From: Plant growth regulators improve nitrogen metabolism, yield, and quality of soybean–rhizobia symbiosisEffect of plant growth regulators and rhizobia on nitrogen metabolism-related indicators. A Content of nitrate nitrogen. B Content of free amino acids. C Activity of nitrate reductase. Each bar is the mean of three independent experiments. Student’s t test was used to evaluate the difference between the control and the treatmentsBack to article page