Table 1.

Ions, hydrogen peroxide, malondialdehyde (MDA), carbohydrates, proteins, free amino acids, and polyphenols in shoots and roots of maize plants hydroponically grown in control (high N) and stress (low N) nitrogen conditions with and without 1µM omeprazole (OP). Values are mean ± s.d. (n = 3).

	Shoot																Root
	High N				High N +OP				Low N				Low N +OP				High N				High N +OP				Low N				Low N +OP
Carbohydrates (µmol g -1 FW)
Glucose	3.33	±	1.10	c	4.22	±	0.53	c	5.30	±	0.23	b	6.71	±	0.70	a	5.05	±	0.37	bc	4.83	±	0.22	c	6.40	±	1.25	b	8.99	±	0.91	a
Fructose	2.53	±	0.19	a	1.76	±	0.02	b	1.93	±	0.63	ab	2.76	±	0.94	a	2.35	±	0.63	a	0.66	±	0.48	b	2.20	±	0.66	ab	1.35	±	0.25	b
Starch	5.57	±	1.52	c	11.03	±	2.98	b	10.06	±	3.52	bc	38.87	±	8.05	a	5.67	±	1.13	c	10.49	±	3.52	b	13.17	±	7.47	bc	43.90	±	9.00	a
Sucrose	1.12	±	0.10	c	0.82	±	0.03	d	1.44	±	0.14	b	2.29	±	0.23	a	1.80	±	0.48	a	0.84	±	0.22	b	1.17	±	0.13	b	2.30	±	0.62	a
Soluble proteins (mg g-1 FW)
Soluble proteins	6.35	±	1.60	a	4.61	±	0.37	a	4.49	±	0.18	a	3.58	±	0.49	b	0.65	±	0.38	c	1.52	±	0.41	b	1.63	±	0.25	b	3.22	±	0.67	a
Amino acids (µmol g -1 FW)
Total amino acid	30.85	±	5.99	a	21.45	±	2.12	b	13.20	±	4.10	c	36.44	±	8.57	a	31.03	±	6.96	b	44.97	±	6.76	a	10.88	±	0.93	d	19.33	±	3.35	c
Alanine	1.31	±	0.26	b	0.92	±	0.08	c	2.07	±	0.70	b	7.54	±	1.84	a	0.92	±	0.24	d	2.94	±	0.42	b	1.76	±	0.30	c	7.48	±	1.61	a
Asparagine	21.88	±	4.35	a	14.57	±	1.58	b	2.84	±	0.92	d	7.97	±	1.77	c	17.19	±	4.08	a	24.07	±	3.52	a	1.29	±	0.17	b	1.54	±	0.32	b
Aspartate	0.58	±	0.11	b	0.43	±	0.03	c	0.57	±	0.17	bc	1.08	±	0.24	a	1.42	±	0.36	ab	1.66	±	0.38	a	1.00	±	0.10	b	1.20	±	0.15	ab
BCAAs	0.38	±	0.14	b	0.29	±	0.02	b	0.34	±	0.05	b	0.79	±	0.12	a	0.75	±	0.13	a	0.87	±	0.09	a	0.76	±	0.09	a	0.79	±	0.12	a
GABA	0.03	±	0.01	bc	0.03	±	0.00	c	0.04	±	0.01	b	0.18	±	0.05	a	0.08	±	0.02	b	0.12	±	0.03	ab	0.04	±	0.01	c	0.18	±	0.04	a
Glutamate	1.65	±	0.32	b	1.12	±	0.07	c	1.72	±	0.57	bc	3.57	±	0.75	a	2.65	±	0.42	ab	2.88	±	0.59	ab	2.10	±	0.24	b	3.22	±	0.41	a
Glutamine	0.96	±	0.20	b	0.30	±	0.02	c	0.69	±	0.23	b	2.24	±	0.73	a	3.92	±	0.98	b	7.81	±	1.08	a	1.24	±	0.10	c	1.38	±	0.24	c
Glycine	1.45	±	0.23	bc	1.41	±	0.09	c	2.15	±	0.59	b	4.26	±	1.03	a	0.82	±	0.09	a	0.53	±	0.06	b	0.23	±	0.03	c	0.43	±	0.06	b
Minor amino acids	0.80	±	0.22	b	0.62	±	0.05	b	0.72	±	0.15	b	2.35	±	0.41	a	1.56	±	0.31	ab	2.05	±	0.29	a	1.45	±	0.16	b	1.48	±	0.25	b
Monoethanolamine	0.27	±	0.06	b	0.20	±	0.02	b	0.24	±	0.09	b	0.60	±	0.15	a	0.46	±	0.11	a	0.43	±	0.10	a	0.30	±	0.01	b	0.38	±	0.04	a
Ornithine	0.24	±	0.05	a	0.17	±	0.08	abc	0.11	±	0.01	c	0.15	±	0.01	b	0.90	±	0.15	a	0.90	±	0.08	a	0.40	±	0.07	b	0.32	±	0.03	b
Proline	0.30	±	0.06	ab	0.34	±	0.03	ab	0.30	±	0.01	b	0.38	±	0.04	a	0.27	±	0.01	a	0.33	±	0.06	a	0.22	±	0.01	b	0.35	±	0.08	a
Serine	1.29	±	0.25	b	1.27	±	0.11	b	1.69	±	0.63	b	6.21	±	1.65	a	0.71	±	0.17	b	1.11	±	0.20	a	0.71	±	0.06	b	1.19	±	0.22	a
Threonine	0.09	±	0.02	b	0.07	±	0.02	bc	0.05	±	0.02	c	0.49	±	0.15	a	0.15	±	0.04	ab	0.22	±	0.04	a	0.16	±	0.02	b	0.18	±	0.04	ab
Ions and hydrogen peroxide (µmol g -1 FW)
Acetate	3.48	±	0.30	a	3.10	±	0.37	a	3.27	±	0.72	a	1.95	±	0.18	b	6.05	±	0.33	a	5.76	±	0.68	a	4.41	±	0.62	b	4.32	±	0.20	b
Chloride	62.51	±	2.95	a	52.53	±	2.11	b	72.69	±	16.06	a	48.63	±	1.59	c	32.08	±	3.54	b	29.27	±	1.62	b	41.95	±	4.41	a	42.83	±	6.09	a
Malate	2.32	±	0.12	c	1.64	±	0.07	d	3.85	±	0.93	a	2.73	±	0.05	b	1.05	±	0.10	c	0.64	±	0.11	d	2.09	±	0.25	b	2.74	±	0.18	a
Nitrate	36.92	±	1.56	b	41.51	±	1.94	a	35.34	±	3.48	b	35.19	±	0.74	b	32.76	±	0.72	a	24.18	±	0.78	b	21.93	±	1.70	b	17.38	±	1.00	c
Oxalacetate	2.16	±	0.10	a	1.97	±	0.25	a	0.93	±	0.14	c	1.21	±	0.12	b	4.65	±	0.42	a	3.78	±	0.23	b	3.96	±	0.64	ab	3.57	±	0.13	b
Sulphate	1.82	±	0.08	b	2.02	±	0.03	a	2.07	±	0.32	ab	1.28	±	0.03	c	7.84	±	0.60	c	7.08	±	0.45	c	12.26	±	1.07	a	10.57	±	0.16	b
Hydrogen peroxide	3.10	±	0.66	c	3.23	±	0.31	c	7.38	±	0.64	a	4.70	±	0.34	b	2.74	±	0.34	a	2.70	±	0.57	a	2.63	±	0.23	a	1.81	±	0.23	b
Other compounds
MDA (nmol g-1 FW)	28.70	±	0.51	b	34.32	±	4.93	a	24.12	±	3.50	c	28.45	±	0.87	bc	81.00	±	10.67	a	83.91	±	8.57	a	51.23	±	5.75	b	48.78	±	2.32	b
Polyphenols (mgGAE g-1 FW)	2.34	±	0.19	a	1.99	±	0.08	b	2.35	±	0.23	a	1.74	±	0.13	c	1.15	±	0.13	a	1.35	±	0.18	a	1.34	±	0.21	a	1.32	±	0.06	a

Means in the same rows with different letters are significantly different (p < 0.05, Student's t-test).