Table 1.

Amino Acid Levels in 4-Week-Old Plants Grown in Ambient Air or High CO₂ Conditions

AA	Wild Type	dKO Mutant	shm1-1 Mutant
Gly	0.37 ± 0.04	26.2 ± 6.1**	38.5 ± 2.8**
Gly↑	0.32 ± 0.07	0.46 ± 0.09*	0.44 ± 0.17*
Ser	2.06 ± 0.30	1.66 ± 0.38	5.60 ± 0.57**
Ser↑	1.97 ± 0.29	2.96 ± 0.68	1.47 ± 0.47
Asp	2.12 ± 0.14	0.61 ± 0.26**	0.43 ± 0.08**
Glu	2.83 ± 0.10	1.60 ± 0.42**	0.68 ± 0.59*
Asn	0.43 ± 0.05	0.28 ± 0.06*	3.98 ± 0.89*
Gln	5.94 ± 0.75	2.31 ± 0.41**	13.5 ± 1.1**
His	0.047 ± 0.005	0.17 ± 0.07*	1.21 ± 0.08**
Thr	0.95 ± 0.13	0.77 ± 0.07	1.61 ± 0.07**
Arg	0.064 ± 0.005	0.10 ± 0.02*	1.77 ± 0.40*
Ala	1.20 ± 0.04	0.39 ± 0.09**	0.36 ± 0.01**
Pro	0.40 ± 0.10	0.56 ± 0.18	0.98 ± 0.58
Tyr	0.014 ± 0.003	0.056 ± 0.012**	0.20 ± 0.04*
Val	0.10 ± 0.01	0.14 ± 0.01**	0.43 ± 0.06**
Met	0.026 ± 0.003	0.011 ± 0.001**	0.058 ± 0.008*
Ileu	0.028 ± 0.001	0.058 ± 0.005**	0.21 ± 0.07*
Leu	0.035 ± 0.002	0.083 ± 0.010**	0.21 ± 0.05*
Lys	0.025 ± 0.001	0.073 ± 0.008**	0.18 ± 0.04*
Phe	0.036 ± 0.005	0.12 ± 0.03**	0.64 ± 0.21*

Amino acid (AA) levels were analyzed in plant leaf extracts (four biological replicates) by HPLC and fluorescence detection. Gly and Ser levels in plants grown at high CO₂ levels (↑) were analyzed by quantitative GC-MS analysis using deuteriated Gly and Ser as internal standards, while the levels of amino acids in plants grown in ambient CO₂ conditions were analyzed by HPLC. The levels are expressed as an average ± sd in nmol mg⁻¹ dry weight. Levels of amino acids in dKO and/or shm1-1 mutants that increased more than threefold or that were below 40% of the wild type are in bold. Asterisks represent statistically significant Student's t test values when mutants were compared with the wild type (P < 0.05* or P < 0.01**).