Vandenhove H, Cuypers A, Van Hees M, Koppen G, Wannijn J
Protection Research Unit, Section of Radioecology, Belgian Nuclear Research Center (SCK-CEN), Radiation Boeretang 200, 2400 Mol, Belgium.
Plant Physiol Biochem. 2006 Nov-Dec;44(11-12):795-805. doi: 10.1016/j.plaphy.2006.10.013. Epub 2006 Oct 27.
The present study aimed to analyze the biological effects induced by bioaccumulation of uranium in Phaseolus vulgaris. Ten-day-old seedlings were exposed to 0, 0.1, 1, 10, 100 and 1000 microM U in diluted Hoagland solution. Following 1, 2, 4 and 7 days' exposure, plants were monitored for uranium uptake, biometric parameters, capacities of enzymes involved in the anti-oxidative defense mechanisms (GPOD, SPOD, GLUR, SOD, ICDH, G-6P-DH), glutathione (GSH) pool and DNA integrity. Uranium contents were up to 900-fold higher in roots (31-14,916 mg kg(-1) FW following 7 days' exposure to 0.1 and 1000 microM U, respectively) as compared to primary leaves (1-16 mg kg(-1) FW following 7 days' exposure to 0.1 and 1000 microM U, respectively). Uranium exposure did not significantly affect plant growth compared to the control. For all enzymes studied, except SOD, enzyme capacities in roots were slightly stimulated with increasing contaminant concentrations (though not significantly). For roots exposed to 1000 microM U, enzyme capacities were significantly reduced. Enzyme capacities in leaves were not affected by uranium treatment. Total and reduced GSH levels were higher in primary leaves of uranium (</=100 microM U) exposed plants than in control plants. When exposed to 1000 microM U, level of total and reduced GSH dropped. These results indicate that uranium can cause oxidative stress and cellular redox imbalance. Root DNA integrity was hampered at the highest external uranium concentration. For P. vulgaris the uranium toxicity threshold is expected to be between 100 and 1000 microM U.
本研究旨在分析铀在菜豆中生物累积所诱导的生物学效应。将10日龄的幼苗置于稀释的霍格兰溶液中，分别暴露于0、0.1、1、10、100和1000微摩尔/升的铀环境中。在暴露1、2、4和7天后，监测植株的铀吸收量、生物特征参数、参与抗氧化防御机制的酶（谷胱甘肽过氧化物酶、愈创木酚过氧化物酶、愈创木酚酶、超氧化物歧化酶、异柠檬酸脱氢酶、6-磷酸葡萄糖脱氢酶）活性、谷胱甘肽（GSH）含量以及DNA完整性。与初生叶相比，根部的铀含量在暴露7天后分别为0.1和1000微摩尔/升时高达900倍（分别为31 - 14916毫克/千克鲜重）（初生叶在暴露7天后分别为0.1和1000微摩尔/升时为1 - 16毫克/千克鲜重）。与对照相比，铀暴露对植株生长没有显著影响。对于所研究的所有酶，除超氧化物歧化酶外，根部的酶活性随污染物浓度增加略有刺激（尽管不显著）。对于暴露于1000微摩尔/升铀的根部，酶活性显著降低。叶片中的酶活性不受铀处理的影响。暴露于铀（≤100微摩尔/升）的植株初生叶中总谷胱甘肽和还原型谷胱甘肽水平高于对照植株。当暴露于1000微摩尔/升铀时，总谷胱甘肽和还原型谷胱甘肽水平下降。这些结果表明，铀可导致氧化应激和细胞氧化还原失衡。在外部铀浓度最高时，根部DNA完整性受到损害。对于菜豆而言，铀毒性阈值预计在100至1000微摩尔/升之间。
