Table 4.

Labeling of the glutamate pool via absorption of ${}^{13}{\text{NH}}_4^{+}$ in entire leaves of transgenic plants treated with 1 mM MSX for 1.5 hours before feeding. Leaf petioles were recut under water. Tracer exposure was for 15 minutes. Incorporation is expressed as a percentage of the label input plus or minus the range detected among 3 individual plant replicates and three measurement replicates.

	GUS	GDH10	BAR
Glu	2.9 ± 1.3	7.0 ± 0.6	2.8 ± 0.7
Gln	1.7 ± 0.1	8.5 ± 1.9	1.5 ± 0.9
${\text{NH}}_4^{+}$	95.3 ± 2.3	84.0 ± 2.4	95.0 ± 4.1