Goggin Danica E, Colmer Timothy D
School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Funct Plant Biol. 2005 Jul;32(6):495-506. doi: 10.1071/FP04194.
The effects of continuous and intermittent anoxia on components of the antioxidant defence system were evaluated in the expanded zones of wheat seedling roots. Intermittent anoxia caused oxidative stress (measured by the proportion of reduced glutathione) after three cycles of anoxia-aeration. The concentration of glutathione and activities of glutathione reductase (GR) and catalase (CAT) were decreased by 50% under both continuous and intermittent anoxia. Ascorbate peroxidase (APX) activity was unaffected by anoxia but stimulated almost 2-fold during the aerated periods of intermittent anoxia. Superoxide dismutase activity was decreased by 20% under continuous anoxia but ultimately returned to aerated activities under intermittent anoxia. Membrane damage appeared to be negligible or reversible, as K concentrations recovered to original levels under intermittent anoxia and there was no increase in terminal lipid peroxidation products. Addition of 5 mm exogenous ascorbate to intermittently anoxic roots prevented oxidative stress and avoided the decreases in glutathione, GR and CAT. Therefore, it is likely that the oxidative stress resulted from inadequate levels of, or damage to, these two enzymes.
在小麦幼苗根系的伸长区评估了持续缺氧和间歇性缺氧对抗氧化防御系统各组分的影响。在经历三个缺氧 - 通气循环后，间歇性缺氧引发了氧化应激（通过还原型谷胱甘肽的比例来衡量）。在持续缺氧和间歇性缺氧条件下，谷胱甘肽的浓度以及谷胱甘肽还原酶（GR）和过氧化氢酶（CAT）的活性均降低了50%。抗坏血酸过氧化物酶（APX）的活性不受缺氧影响，但在间歇性缺氧的通气期几乎被刺激增加了2倍。在持续缺氧条件下，超氧化物歧化酶活性降低了20%，但在间歇性缺氧条件下最终恢复到通气时的活性水平。膜损伤似乎可以忽略不计或可逆，因为在间歇性缺氧条件下钾离子浓度恢复到原始水平，且脂质过氧化终产物没有增加。向间歇性缺氧的根系添加5 mM外源抗坏血酸可防止氧化应激，并避免谷胱甘肽、GR和CAT的减少。因此，氧化应激很可能是由这两种酶的水平不足或损伤所致。
