Biemelt S, Keetman U, Albrecht G
Humboldt-Universität zu Berlin, Institut für Biologie, Botanik und Biologiedidaktik, Späthstrasse 80/81, D-12437 Berlin, Germany (S.B., G.A.)
Plant Physiol. 1998 Feb 1;116(2):651-8. doi: 10.1104/pp.116.2.651.
The response of the ascorbate-glutathione cycle was investigated in roots of young wheat (Triticum aestivum L.) seedlings that were deprived of oxygen either by subjecting them to root hypoxia or to entire plant anoxia and then re-aerated. Although higher total levels of ascorbate and glutathione were observed under hypoxia, only the total amount of ascorbate was increased under anoxia. Under both treatments a significant increase in the reduced form of ascorbate and glutathione was found, resulting in increased reduction states. Upon the onset of re-aeration the ratios started to decline rapidly, indicating oxidative stress. Hypoxia caused higher activity of ascorbate peroxidase, whereas activities of monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase were diminished or only slightly influenced. Under anoxia, activities of ascorbate peroxidase and glutathione reductase decreased significantly to 39 and 62%, respectively. However, after re-aeration of hypoxically or anoxically pretreated roots, activity of enzymes approached the control levels. This corresponds with the restoration of the high reduction state of ascorbate and glutathione within 16 to 96 h of re-aeration, depending on the previous duration of anoxia. Apparently, anoxia followed by re-aeration more severely impairs entire plant metabolism compared with hypoxia, thus leading to decreased viability.
研究了通过使小麦（Triticum aestivum L.）幼苗根部缺氧或整株缺氧然后再通气，来观察抗坏血酸-谷胱甘肽循环的响应。尽管在缺氧条件下观察到抗坏血酸和谷胱甘肽的总水平较高，但仅在无氧条件下抗坏血酸的总量增加。在两种处理下，抗坏血酸和谷胱甘肽的还原形式均显著增加，导致还原态增加。再通气开始后，这些比率开始迅速下降，表明存在氧化应激。缺氧导致抗坏血酸过氧化物酶活性升高，而单脱氢抗坏血酸还原酶、脱氢抗坏血酸还原酶和谷胱甘肽还原酶的活性降低或仅受到轻微影响。在无氧条件下，抗坏血酸过氧化物酶和谷胱甘肽还原酶的活性分别显著下降至39%和62%。然而，在对缺氧或无氧预处理过的根进行再通气后，酶的活性接近对照水平。这与再通气16至96小时内抗坏血酸和谷胱甘肽的高还原态的恢复相对应，这取决于之前缺氧的持续时间。显然，与缺氧相比，无氧后再通气对整株植物代谢的损害更严重，从而导致活力下降。
