Fig. 2

Amino acid contents in the growth medium and rice roots during the time course of glutamate treatment. 17-day-old nitrogen-starved rice seedlings were transferred to hydroponics containing 2.5 mM glutamate for 24 h. a The contents of glutamate left in the hydroponics were measured over the 24-h time course. b Contents of glutamate, glutamine, aspartate, alanine, serine, and asparagine in the roots were measured during the time course of glutamate treatment. Fold change indicates the relative amounts of amino acids in 2.5 mM glutamate-treated roots (0.25-24 h) compared to those of control (0 h). Data are means ± SD (n = 5). Different letters indicate significant differences between treatments, tested by one-way ANOVA followed by Tukey’s test (P < 0.05)