不同生境两种生态型芦苇的抗氧化系统

以分布于甘肃临泽平川乡的两种芦苇生态型——水生芦苇(水芦)和重度盐化草甸芦苇(盐芦)叶片为材料，研究了其抗氧化系统的特征。结果表明，与水芦相比，盐芦中未出现活性氧和MDA(丙二醛)的积累，抗氧化酶SOD(超氧化物歧化酶)、CAT(过氧化氢酶)、POD(过氧化物酶)和APX(抗坏血酸过氧化物酶)的活性显著升高。总抗坏血酸和类胡萝卜素含量在两种生态型芦苇中没有差异，但还原型抗坏血酸和总谷胱甘肽含量在盐芦中显著升高。而且，盐芦的LOX(脂氧合酶)活性比水芦低。这些结果表明，盐芦中有效的抗氧化防御系统对抵抗盐渍胁迫起着重要的作用。此外，盐芦中高活性的Ca^2 -和Mg^2 -ATPase对细胞中过多离子的转运以及避免离子毒害起着重要的作用。

Antioxidant system in two ecotypes of reed (Phragmites communis) leaves from different habitats

Using plants possessing stable genetic tolerance/resistance under natural environmental conditions to study the mechanism of plants' adaptation to environmental stress are very significant. However, relevant work is very limited. In this work, two ecotypes of reed (Phragmites communis Trin.), referred to as "swamp reed (SR)" and "heavy salt meadow reed (HSMR)" according to their habitats, growing in Pingchuan Town, Linze County, Gansu Province (China) were investigated for the antioxidant system in their leaves. The results showed that compared with the SR, there were no accumulations of reactive oxygen species and MDA (malondialdehyde) in the HSMR. The activities of SOD (superoxide dismutase), CAT (catalase), POD (peroxidase) and APX (ascorbate peroxidase) were significantly higher in the HSMR than those in the SR. There were no differences in the contents of total ascorbic acid and carotenoids between the two ecotypes, while the contents of reduced ascorbic acid and total glutathione were higher in the HSMR than that in the SR. Moreover, the LOX (lipoxygenase) in the HSMR showed a decreased activity compared with the SR. These results suggested that more efficient antioxidant systems in the HSMR contribute to its tolerance / resistance to the saline stress. In addition, higher activities of membrane-bound Ca~(2+)- and Mg~(2+)-ATPase in the HSMR might contribute to transporting excessive ions out of cells, therefore avoiding ion toxicity when this reed ecotype grew in saline habitat.