Institute of Plant Physiology, Polish Academy of Sciences, Podłuzna 3, 30-239 Kraków, Poland.
J Plant Physiol. 2010 Jan 1;167(1):28-33. doi: 10.1016/j.jplph.2009.07.003. Epub 2009 Aug 13.
Selenium appears to be an important protective agent that decreases cadmium-induced toxic effects in animals and plants. The aim of these studies was to investigate the changes of properties of chloroplast membranes obtained from Cd-treated rape seedlings caused by Se additions. Chloroplasts were isolated from leaves of 3-week-old rape plants cultured on Murashige-Skoog media supplied with 2 microM Na(2)SeO(4) and/or 400 microM CdCl(2) under in vitro conditions. The following physicochemical characteristics of chloroplasts were chosen as indicators of Se-effects: average size, zeta potential, ultrastructure, lipid and fatty acid composition and fluidity of envelope membrane. The results suggest that Se can partly counterbalance the destructive effects of Cd. This protective action led to an increase of chloroplast size reduced by Cd treatment and rebuilt, to some extent, the chloroplast ultrastructure. Lipid and fatty acid composition of chloroplast envelopes modified by Cd showed a decrease in digalactosyl-diacylglycerol content and an increase of content of monogalactosyl-diacylglycerol and phospholipid fractions, as well as an increase of fatty acid saturation of all lipids studied. The change in fatty acid saturation correlated well with a decrease of membrane fluidity and with a diminishing of absolute values of zeta potential. The presence of selenium in cultured media caused a partial reversal of the detected changes, which was especially visible in properties related to the hydrophobic part of an envelope, i.e. fatty acid saturation and fluidity.
硒似乎是一种重要的保护剂，可降低动物和植物中镉诱导的毒性作用。这些研究的目的是研究从 Cd 处理的油菜幼苗中分离的叶绿体膜的特性变化，这些变化是由 Se 添加引起的。叶绿体是从在含有 2 μM Na2SeO4 和/或 400 μM CdCl2 的 Murashige-Skoog 培养基中培养的 3 周龄油菜植物的叶片中分离出来的。选择以下叶绿体的物理化学特性作为 Se 效应的指标：平均大小、ζ 电位、超微结构、脂质和脂肪酸组成以及包膜的流动性。结果表明，Se 可以部分抵消 Cd 的破坏作用。这种保护作用导致 Cd 处理减小的叶绿体大小增加，并在一定程度上重建了叶绿体超微结构。由 Cd 修饰的叶绿体包膜的脂质和脂肪酸组成显示二半乳糖基二酰基甘油含量降低，单半乳糖基二酰基甘油和磷脂部分含量增加，以及所有研究的脂质的脂肪酸饱和度增加。脂肪酸饱和度的变化与膜流动性的降低以及 ζ 电位绝对值的减小密切相关。在培养介质中存在硒会导致检测到的变化部分逆转，这在与包膜疏水区有关的性质上尤其明显，即脂肪酸饱和度和流动性。
