Figure 4. Changes in lateral root (LR) numbers in response to varying external and internal nitrate concentrations in wild-type (WT) and osnar2.1 knockdown lines (r1 and r2).

Rice seedlings were grown for 1 wk in hydroponic medium containing 10 mM NO₃⁻ and then transferred for a further week to media containing 0-10 mM ¹⁵N-NO₃⁻. (a) LR number responding to varying external NO₃⁻ concentrations; (b) LR number responding to varying internal ¹⁵N accumulation levels in the roots. Values are means ± SE (n = 6). *P < 0.05 (ANOVA) comparing WT plants and two mutant lines in the same treatment.