Departamento de Biologia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brazil.
Biometals. 2010 Apr;23(2):295-305. doi: 10.1007/s10534-009-9287-3.
Oxidative stress caused by mercury (Hg) was investigated in Pfaffia glomerata plantlets grown in nutrient solution using sand as substrate. Thirty-day-old acclimated plants were treated for 9 days with four Hg levels (0, 1, 25 and 50 microM) in the substrate. Parameters such as growth, tissue Hg concentration, toxicity indicators (delta-aminolevulinic acid dehidratase, delta-ALA-D, activity), oxidative damage markers (TBARS, lipid peroxidation, and H(2)O(2) concentration) and enzymatic (superoxide dismutase, SOD, catalase, CAT, and ascorbate peroxidase, APX) and non-enzymatic (non-protein thiols, NPSH, ascorbic acid, AsA, and proline concentration) antioxidants were investigated. Tissue Hg concentration increased with Hg levels. Root and shoot fresh weight and delta-ALA-D activity were significantly decreased at 50 microM Hg, and chlorophyll and carotenoid concentration were not affected. Shoot H(2)O(2) concentration increased curvilinearly with Hg levels, whereas lipid peroxidation increased at 25 and 50 microM Hg, respectively, in roots and shoots. SOD activity showed a straight correlation with H(2)O(2) concentration, whereas CAT activity increased only in shoots at 1 and 50 microM Hg. Shoot APX activity was either decreased at 1 microM Hg or increased at 50 lM Hg. Conversely, root APX activity was only increased at 1 microM Hg. In general, AsA, NPSH and proline concentrations increased upon addition of Hg, with the exception of proline in roots, which decreased. These changes in enzymatic and non-enzymatic antioxidants had a significant protective effect on P. glomerata plantlets under mild Hg-stressed conditions.
在以沙为基质的营养溶液中培养 Pfaffia glomerata 幼苗时，研究了汞 (Hg) 引起的氧化应激。30 天龄的适应期植物在基质中用 4 种 Hg 水平（0、1、25 和 50 μM）处理 9 天。研究了生长、组织 Hg 浓度、毒性指标（δ-氨基酮戊酸脱水酶、δ-ALA-D 活性）、氧化损伤标志物（TBARS、脂质过氧化、H2O2 浓度）、酶（超氧化物歧化酶、SOD、过氧化氢酶、CAT、抗坏血酸过氧化物酶、APX）和非酶（非蛋白巯基、NPSH、抗坏血酸、AsA 和脯氨酸浓度）抗氧化剂等参数。组织 Hg 浓度随 Hg 水平的增加而增加。根和茎的鲜重和 δ-ALA-D 活性在 50 μM Hg 时显著降低，而叶绿素和类胡萝卜素浓度不受影响。H2O2 浓度在 shoots 中随 Hg 水平呈曲线增加，而在 roots 中分别在 25 和 50 μM Hg 时增加。SOD 活性与 H2O2 浓度呈直线相关，而 CAT 活性仅在 1 和 50 μM Hg 时增加。APX 活性在 shoots 中要么在 1 μM Hg 时降低，要么在 50 μM Hg 时增加。相反，root APX 活性仅在 1 μM Hg 时增加。一般来说，添加 Hg 会增加 AsA、NPSH 和脯氨酸的浓度，除了根中的脯氨酸浓度降低。在轻度 Hg 胁迫条件下，这些酶和非酶抗氧化剂的变化对 P. glomerata 幼苗具有显著的保护作用。
