Figure 3

¹⁵NO ₃ ^-uptake in Xenopus oocytes. Mixed mRNA of either synthetic genes (synthetic OsNAR2.1 and OsNRT2.3a) or the original genes (original OsNAR2.1 and OsNRT2.3a) were injected into oocytes. Single oocyte was incubated in MBS with 0.5 mM Na¹⁵NO₃ for 8 h and 16 h, and then washed four times with cold 0.5 mM NaNO₃ before ¹⁵N analysis. Data are averaged and SE of five oocytes. a, b and c indicate the significant difference at p ≤ 0.05 of same template DNA between different treatments at 5% of probability. The example shown is representative of the results from two frogs.