Table - link
||Tobacco Nicotiana plumbaginifolia
||Brugiere N, Dubois F, Limami AM, Lelandais M, Roux Y, Sangwan RS, Hirel B. Glutamine synthetase in the phloem plays a major role in controlling proline production Plant Cell. 1999 Oct11(10):1995-2012. p. 2005 tables 2 & 3PubMed ID10521528
||Mutants with reduced Glutamine synthase (GS) levels were compared to controls: To determine the effect of decreased levels of GS activity in
the phloem on ammonia assimilation and amino acid biosynthesis
and transport, transgenic and control plants were
first grown for 8 weeks on a nitrate-containing solution (N12 solution) and then forced to assimilate large amounts of ammonium
after a transfer to a complete nutrient solution containing
8 mM NH4+ as the sole nitrogen source for an
additional 2 weeks.
||See note under table. Compared with untransformed controls, no significant differences
in the total amino acid concentration were observed
in leaves, stems, roots, xylem sap, or phloem sap of
transgenic plants (table link).