Cargnelutti Denise, Tabaldi Luciane Almeri, Spanevello Rosélia Maria, de Oliveira Jucoski Gladis, Battisti Vanessa, Redin Marciel, Linares Carlos Eduardo Blanco, Dressler Valderi Luiz, de Moraes Flores Erico Marlom, Nicoloso Fernando Teixeira, Morsch Vera Maria, Schetinger Maria Rosa Chitolina
Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil.
Chemosphere. 2006 Nov;65(6):999-1006. doi: 10.1016/j.chemosphere.2006.03.037. Epub 2006 May 3.
In this study, the effects of exogenous mercury (HgCl(2)) on time-dependent changes in the activities of antioxidant enzymes (catalase and ascorbate peroxidase), lipid peroxidation, chlorophyll content and protein oxidation in cucumber seedlings (Cucumis sativus L.) were investigated. Cucumber seedlings were exposed to from 0 to 500microM of HgCl(2) during 10 and 15 days. Hg was readily absorbed by growing seedlings, and its content was greater in the roots than the in shoot. Time and concentration-dependent reduction in root and shoot length was observed at all concentrations tested, equally in the roots and shoot, at both 10 and 15 days. At 50microM HgCl(2), root fresh weight of 15-day-old seedlings increased, and at other concentrations, it reduced. For 10-day-old seedlings, reduction in root and shoot fresh biomass was observed. At 15 days, only at 50microM HgCl(2) was there no observed reduction in shoot fresh biomass. Dry weight of roots increased at 500microM both at 10 and 15 days, though at 250microM HgCl(2) there was only an increase at 15 days. There was a significant effect on shoot dry weight at all concentrations tested. Hg-treated seedlings showed elevated levels of lipid peroxides with a concomitant increase in protein oxidation levels, and decreased chlorophyll content when exposed to between 250 and 500microM of HgCl(2). At 10 days, catalase activity increased in seedlings at a moderately toxic level of Hg, whereas at the higher concentration (500microM), there was a marked inhibition. Taken together, our results suggest that Hg induces oxidative stress in cucumber, resulting in plant injury.
在本研究中，研究了外源汞（HgCl₂）对黄瓜幼苗（Cucumis sativus L.）抗氧化酶（过氧化氢酶和抗坏血酸过氧化物酶）活性的时间依赖性变化、脂质过氧化、叶绿素含量和蛋白质氧化的影响。黄瓜幼苗在10天和15天内暴露于0至500μM的HgCl₂中。生长中的幼苗很容易吸收汞，其在根部的含量高于地上部分。在所有测试浓度下，均观察到根和茎长度随时间和浓度的降低，在10天和15天时，根和茎中的情况相同。在50μM HgCl₂时，15日龄幼苗的根鲜重增加，在其他浓度下则降低。对于10日龄幼苗，观察到根和茎的鲜生物量减少。在15天时，仅在50μM HgCl₂时未观察到地上部分鲜生物量的减少。在10天和15天时，500μM时根的干重增加，尽管在250μM HgCl₂时仅在15天时增加。在所有测试浓度下，对地上部分干重均有显著影响。当暴露于250至500μM的HgCl₂时，汞处理的幼苗显示脂质过氧化物水平升高，同时蛋白质氧化水平增加，叶绿素含量降低。在10天时，在中等毒性水平的汞处理下，幼苗中的过氧化氢酶活性增加，而在较高浓度（500μM）时，有明显的抑制作用。综上所述，我们的结果表明汞在黄瓜中诱导氧化应激，导致植物损伤。
