Fig. 4

Effect of nitrogen (N) deficiency on the growth of aln and aah mutants. Aseptically grown 2 WAG seedlings were transplanted to pots containing vermiculite and perlite, and then further grown for 4 weeks with weekly irrigation of N-deficient (2 mM N) and sufficient (20 mM N) nutrient solution. a Dry weight (DW) of whole shoots (n = 16). A linear model with the genotype as a factor was fitted to the data. Asterisks denote significant differences between WT and mutant plants (*P < 0.05, **P < 0.01, two-tailed t-tests based on the model). b Allantoin and allantoate levels were determined on a dry weight (DW) basis for shoots (n = 3). Asterisks denote significant differences in allantoin or allantoate contents between N-deficient and -sufficient conditions for each genotype (*P < 0.05, two-tailed t-tests). n.d., not detected