Peng Chang-Lian, Lin Zhi-Fang, Su Yue-Zeng, Lin Gui-Zhu, Dou Hong-Yan, Zhao Cheng-Xue
College of Life Science, South China Normal University, Guangzhou 510631, China.
South China Institute of Botany, Chinese Academy of Sciences, Guangdong Key Laboratory of Digital Botanical Garden, Guangzhou 510650, China.
Funct Plant Biol. 2006 Sep;33(9):839-846. doi: 10.1071/FP06013.
In the present study, both electron spin resonance (ESR) and chemical detection confirmed that lutein [extracted from alfalfa (Medicago sativa L.)], the most abundant xanthophyll in thylakoids of chloroplasts, could serve as an antioxidant to scavenge reactive oxygen species (ROS) in vitro. Lutein exhibited a greater capacity for scavenging hydroxyl (OH) and superoxide (O) radicals than β-carotene at the same concentration, whereas the opposite trend was observed in the capacity for scavenging singlet oxygen (O). The capacity of lutein for scavenging ROS from high to low is OH > O > O. We hypothesise that lutein plays an important photoprotective role in scavenging O and OH under severe stress. This hypothesis is consistent with our previous report that the lut2 (lutein-deficient) Arabidopsis mutant is more susceptible to damage than the npq1 (lutein-replete but violaxanthin de-epoxidase-deficient) Arabidopsis mutant under severe stress during exposure to high light intensity at low temperature (Peng and Gilmore 2003).
在本研究中，电子自旋共振（ESR）和化学检测均证实，叶黄素[从紫花苜蓿（Medicago sativa L.）中提取]作为叶绿体类囊体中含量最丰富的叶黄素，可以作为抗氧化剂在体外清除活性氧（ROS）。在相同浓度下，叶黄素清除羟基（OH）和超氧阴离子（O）自由基的能力比β-胡萝卜素更强，而在清除单线态氧（O）的能力方面则观察到相反的趋势。叶黄素清除ROS的能力从高到低依次为OH＞O＞O。我们推测，在严重胁迫下，叶黄素在清除O和OH方面发挥着重要的光保护作用。这一推测与我们之前的报道一致，即在低温高光强度胁迫下，叶黄素缺陷型拟南芥突变体lut2比叶黄素充足但紫黄质脱环氧化酶缺陷型拟南芥突变体npq1更易受到损伤（Peng和Gilmore，2003）。
