Ekmekçi Yasemin, Tanyolaç Deniz, Ayhan Beycan
Hacettepe University, Faculty of Science, Department of Biology, Beytepe Campus, Ankara, Turkey.
J Plant Physiol. 2008 Apr 18;165(6):600-11. doi: 10.1016/j.jplph.2007.01.017. Epub 2007 Aug 28.
Effects of cadmium (Cd(2+)) on photosynthetic and antioxidant activities of maize (Zea mays L.) cultivars (3223 and 32D99) were investigated. Fourteen-day-old cultivar seedlings were exposed to different Cd concentrations [0, 0.3, 0.6 and 0.9mM Cd(NO(3))(2) x 4H(2)O] for 8 days. The results of chlorophyll fluorescence indicated that different levels of Cd affected photochemical efficiency in 3223 much more than that in 32D99. In parallel, the level of Cd at 0.9mM caused oxidative damage but did not indicate cessation of PSII activity of the cultivars; plant death was not observed at highly toxic Cd levels. Additionally, the increase in Cd concentration caused loss of chlorophylls and carotenoid and membrane damage in both cultivars, but greater membrane damage was observed in 3223 than in 32D99. Depending on Cd accumulation, a significant reduction in dry biomass was observed in both cultivars at all Cd concentrations. The accumulation of Cd was higher in roots than in leaves for both cultivars. Nevertheless, cultivar 3223 transferred more Cd from roots to leaves than did 32D99. On the other hand, our results suggest that there were similar responses in SOD, APX and GR activities with increasing Cd concentrations for both cultivars. However, POD activity significantly increased at highly toxic Cd levels in 32D99. This result may be regarded as an indication of better tolerance of the Z. mays L. cultivar 32D99 to Cd contamination.
研究了镉（Cd(2+)）对玉米（Zea mays L.）品种（3223和32D99）光合及抗氧化活性的影响。将14日龄的品种幼苗暴露于不同镉浓度[0、0.3、0.6和0.9 mM Cd(NO(3))(2)·4H(2)O]下8天。叶绿素荧光结果表明，不同水平的镉对3223光化学效率的影响远大于32D99。同时，0.9 mM的镉水平造成了氧化损伤，但未表明品种的PSII活性停止；在高毒性镉水平下未观察到植株死亡。此外，镉浓度增加导致两个品种的叶绿素和类胡萝卜素损失以及膜损伤，但3223的膜损伤比32D99更严重。根据镉积累情况，在所有镉浓度下两个品种的干生物量均显著降低。两个品种根中的镉积累量均高于叶。然而，3223品种从根向叶转运的镉比32D99更多。另一方面，我们的结果表明，两个品种的超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性随镉浓度增加有相似的反应。然而，在32D99中，高毒性镉水平下过氧化物酶（POD）活性显著增加。这一结果可被视为玉米品种32D99对镉污染耐受性更好的一个指标。
