Table 1.

Metabolite levels in unstimulated, cold-shocked and wounded maize leaves (N = 5 ± SD).

Metabolite	Content in unstimulated leaves	Content in cold-shocked leaves [μmol g−1 fresh wt]	Content in wounded leaves
Malate	2.10 ± 0.25	2.89 ± 0.18*	1.70 ± 0.45
PEP	0.35 ± 0.05	0.38 ± 0.17	0.27 ± 0.13
Pyruvate	0.54 ± 0.29	0.45 ± 0.15	0.29 ± 0.11
PGA	1.52 ± 0.38	1.61 ± 0.50	0.94 ± 0.16
DHAP	0.68 ± 0.12	1.10 ± 0.17*	0.32 ± 0.13*
GAP	0.04 ± 0.01	0.24 ± 0.05*	0.13 ± 0.01*
Sucrose	0.99 ± 0.18	0.86 ± 0.10	1.35 ± 0.21
Glucose	0.20 ± 0.07	0.18 ± 0.05	0.17 ± 0.09
Fructose	0.08 ± 0.01	0.08 ± 0.01	0.08 ± 0.02
ATP	0.13 ± 0.02	0.17 ± 0.05	0.11 ± 0.04
Starch	1564 ± 398	3640 ± 1050*	1040 ± 86

(Asterisks indicate significant differences to control—P = 0.05—, calculated by student's t-test). The photometrically measured data show that cold-shocked leaves have higher malate, PEP, PGA, TrioseP, ATP and starch levels than untreated leaves, whereas wounded leaves have lower levels of almost all metabolites.