This study investigated biochemical and morphological changes associated to oxidative metabolism during late stages, i.e. 25 days after inoculation of Fusarium oxysporum. f. sp. phaseoli (Fop) in susceptible and resistant roots as well as Fop sensitivity to H₂O₂. Severe cell destruction only occurred in infected susceptible roots, while xylem vessels occlusion was stronger in the resistant genotype. H₂O₂ accumulation occurred in both infected genotypes being associated with cell destruction in susceptible roots and with apparent maintenance of xylem integrity in the resistant one. The activity of peroxidase, NADPH-oxidase, lipoxygenase, superoxide dismutase, ascorbate peroxidase and catalase increased in inoculated resistant roots, while in susceptible ones only lipoxygenase and ascorbate-peroxidase activities increased. Conidium germination and mycelial growth of Fop were reduced in concentrations above 4 and 8 μM of H₂O₂, respectively, where 32 μM completely inhibited mycelial growth. H₂O₂ accumulation seemed to be associated to tissue damage caused by Fop colonization in susceptible roots and to defense responses in some xylem cells in resistant genotype during late stages.

该研究调查了与后期氧化代谢相关的生化和形态学变化，即接种尖孢镰刀菌后 25 天。F。sp. 易感和抗性根中的菜豆( Fop ) 以及Fop对 H ₂ O _{2 的}敏感性。严重的细胞破坏仅发生在受感染的易感根中，而木质部血管闭塞在抗性基因型中更强。H ₂ O ₂在与易感根中的细胞破坏和抗性根中木质部完整性的明显维持相关的两种受感染基因型中都发生了积累。接种抗性根中过氧化物酶、NADPH-氧化酶、脂氧合酶、超氧化物歧化酶、抗坏血酸过氧化物酶和过氧化氢酶的活性增加，而感病根中仅脂氧合酶和抗坏血酸-过氧化物酶活性增加。Fop 的分生孢子萌发和菌丝体生长分别在 4 μM 和 8 μM 以上的 H ₂ O ₂浓度下降低，其中 32 μM 完全抑制菌丝体生长。H ₂ O ₂积累似乎与Fop引起的组织损伤有关 易感根的定植和晚期抗性基因型中某些木质部细胞的防御反应。