Fig. 8

Differential physiologic and molecular responses to nitrogen (N) limitation in allotetraploid rapeseed genotypes. a Relative frequency of SPAD values in a rapeseed panel comprising 102 genotypes under limited N supply. The rapeseed plants that were grown under sufficient N (9.0 mM) condition were then transferred to limited N (0.30 mM) for 7 d, and the SPAD values of their mature leaves were assayed. b Differences in growth performance of the low-N-tolerant and low-N-sensitive genotypes that were identified from the 102 rapeseed accessions. Scale bar: 5 cm. c, d The qRT-PCR assay results of the BnamiR827-BnaC5.NLA1-BnaC6.NRT1.7b /BnaC6.NRT1.7b regulatory circuit in the shoots (c) and roots (d). The rapeseed plants that were grown under sufficient N (9.0 mM) condition were then transferred to limited N (0.30 mM) for 3 d. Five extremely low-N-tolerant genotypes and five extremely low-N-sensitive genotypes were selected, and the shoots and roots were individually sampled for the qRT-PCR assays. Significant difference was determined by two-tailed paired t-test. *: p < 0.05; **: p < 0.01; ***: p < 0.001