Table I. Transgenic plants contain higher levels of free amino acids under control conditions.

The quantification of free amino acid contents was performed using shoot material of wild-type and transgenic plants grown under well-watered and drought stress conditions. Values are means ± se for each compound and were calculated from a minimum of four to five individual plants per genotype in each treatment. Significant differences were calculated using a two-tailed Student’s t test. Amino acid values are given in nmol g⁻¹ fresh weight. Boldface values indicate significant differences (P < 0.05) for the same genotype under drought stress as compared to control conditions. Asterisks indicate significant differences compared with the wild type for the same treatment (*, P < 0.05; **, P < 0.01; and ***, P < 0.001).

Amino Acid	Control			Drought Stress
	Wild Type	pEXP:CKX2		Wild Type	pEXP:CKX2
		#16	#72		#16	#72
His	25 ± 16	121 ± 11**	82 ± 5*	245 ± 18	219 ± 5	149 ± 10**
Asn	127 ± 32	1,688 ± 133***	1,546 ± 182*	3,846 ± 402	4,907 ± 185	3,564 ± 280
Ser	127 ± 49	1,268 ± 85***	1,009 ± 46***	1,815 ± 120	2,021 ± 33	1,585 ± 95
Gln	603 ± 363	1,303 ± 87	1,398 ± 168	2,041 ± 87	2,147 ± 150	1,643 ± 117
Gly	41 ± 27	174 ± 17**	134 ± 15*	246 ± 14	261 ± 3	245 ± 41
Asp	853 ± 616	2,140 ± 200	1,542 ± 107	2,169 ± 57	2,390 ± 82	2,125 ± 42
Glu	808 ± 607	2,970 ± 310*	2,359 ± 144	3,795 ± 182	3,628 ± 78	3,406 ± 193
Thr	298 ± 207	1,015 ± 89*	860 ± 43	2,042 ± 174	2,141 ± 40	1,620 ± 81
Ala	240 ± 178	1,071 ± 72**	1,008 ± 29*	1,331 ± 79	1,579 ± 45*	1,232 ± 50
Pro	8 ± 2	52 ± 7**	43 ± 5*	4,995 ± 715	2,885 ± 248	896 ± 234**
Cys	13 ± 2	35 ± 2***	43 ± 8	34 ± 4	26 ± 1	27 ± 1
Lys	3 ± 0.3	77 ± 22*	57 ± 11*	251 ± 21	175 ± 12*	124 ± 21**
Tyr	36 ± 9	53 ± 9	60 ± 18	88 ± 2	78 ± 6	61 ± 10
Met	302 ± 25	35 ± 26***	10 ± 5**	10 ± 4	12 ± 4	5 ± 1
Val	70 ± 50	278 ± 34*	211 ± 19*	688 ± 87	647 ± 30	41 ± 512*
Ile	32 ± 22	98 ± 13*	73 ± 9	315 ± 50	233 ± 23	145 ± 11*
Leu	32 ± 24	94 ± 18	67 ± 11	285 ± 40	195 ± 23	127 ± 7*
Phe	31 ± 16	91 ± 10*	69 ± 2	144 ± 12	104 ± 3*	93 ± 5*
GABA	29 ± 23	104 ± 13*	136 ± 24*	187 ± 23	169 ± 12	97 ± 5*
Total	3,678 ± 2,268	12,667 ± 1,158	10,704 ± 851	24,527 ± 2,091	23,817 ± 983	17,185 ± 1,716