Figure 1.

Number of new lateral roots on new primary roots. WT (WS, black bars), mutant (atnar2.1-1, white bars), overexpresser (WSRolDNpNRT2.1, cross-hatched bars) and cross (RolDNpNRT2.1X atnar2.1-1, grey bars) plants were grown on vertical agar plates on 10 mM NO₃⁻ for 7 d and then transferred to either 0.5 or 10 mM NO₃⁻ for a further 6 d (13 d of total growth). Materials and Methods described previously.⁵ Mean values ± SD of 12 seedling are shown. On 0.5 mM nitrate both atnar2.1-1 and RolDNpNRT2.1X atnar2.1-1 show significantly less new lateral roots when compared with wild type and WSRolDNpNRT2.1. Statistical comparisons of means between treatments or genotypes were performed by the pooled Student's t test using the Sigmaplot software (Systat Software UK, London, UK).