Table I.

Antioxidant metabolites and enzymes in the periphery (cortex plus nodule parenchyma) and infected zone of bean and cowpea nodules

Antioxidant	Common Bean		Cowpea
	Periphery	Infected zone	Periphery	Infected zone
Ascorbate	124  ± 9 a	86  ± 11 b	50  ± 4 a	30  ± 4 b
(Homo)glutathionea	37.8  ± 1.0 a	26.3  ± 2.0 b	26.4  ± 2.0 a	12.0  ± 1.2 b
AP	1.08  ± 0.03 a	1.01  ± 0.05 a	1.40  ± 0.07 a	1.38  ± 0.02 a
Dehydroascorbate reductase	51.6  ± 4.9 a	29.1  ± 2.7 b	35.1  ± 2.9 a	40.2  ± 1.7 a
Monodehydroascorbate reductase	384  ± 16 a	244  ± 5 b	340  ± 22 a	217  ± 9 b
(Homo)glutathione reductaseb	41.0  ± 2.9 a	52.1  ± 1.2 b	44.3  ± 2.2 a	41.1  ± 1.4 a
Catalase	125  ± 3 a	163  ± 5 b	82  ± 8 a	150  ± 12 b

Metabolite contents are expressed as nmol mg⁻¹ protein. Activities are expressed as μmol substrate min⁻¹ mg⁻¹ protein (catalase and AP) or in nmol substrate or product min⁻¹ mg⁻¹ protein (others). Values are means ± se (n = 4–7). For each species, means denoted by the same letter do not differ significantly at P = 0.05 based on Duncan's multiple-range test.

^aReduced plus oxidized (homo)glutathione. 

^bAssayed using oxidized glutathione as a substrate.