Fig. 1

Tissue-specific differential relative expression levels of OsPHR3 during growth under different regimes of N variants. Seeds of the wild-type were grown hydroponically in IRRI solution for 2 weeks, starved for N for 3 d and then supplied for 24 h with nutrient solution containing high NH₄⁺ (H NH₄⁺, 5 mM), low NH₄⁺ (L NH₄⁺, 0.25 mM), high NO₃⁻ (H NO₃⁻, 5 mM), low NO₃⁻ (L NO₃⁻, 0.25 mM), 2.5 mM N (1.25 mM NH₄⁺ and 1.25 mM NO₃⁻,) and 0.25 mM (0.125 mM NH₄⁺ and 0.125 mM NO₃⁻). Root and shoot were harvested for the qRT-PCR analysis of the relative expression levels of OsPHR3 in (a) high and low NH₄⁺ or NO₃⁻ and (b) 2.5 mM N and 0.25 mM N conditions. Actin (OsRac1; LOC_Os03g50885) was used as an internal control and the values for H NH₄⁺, H NO₃⁻ and + N were normalized to 1. Values are means ±SE (n = 3) and different letters on the histograms indicate that the values differ significantly (P < 0.05, one-way ANOVA)