Laboratoire de Physiologie et Génétique végétales, UMR PIAF 547-UBP/INRA, Université Blaise Pascal-Clermont II, Campus universitaire des Cézeaux, Aubiere, France.
Ecotoxicology. 2011 Mar;20(2):329-36. doi: 10.1007/s10646-010-0582-0. Epub 2010 Dec 14.
Kinetics of stress responses to Cd exposure (50, 100 and 200 μM) expanding from 12 to 48 h were studied in roots of hydroponically cultivated-Vicia faba seedlings. The heavy metal induced toxicity symptoms and growth arrest of Vicia roots gradually to the Cd concentration and duration of the treatment. The intracellular oxidative stress was evaluated with the H(2)O(2) production. The H(2)O(2) content increased gradually with the sequestered Cd and root growth inhibition. Lipid peroxidation-evidenced by malondialdehyde (MDA) content and Evans blue uptake-and genotoxicity-evidenced by mitotic index (MI) and micronuclei (MCN) values-were concomitantly investigated in root tips. By 12 h, root meristematic cells lost 15% of their mitotic activity under 50 or 100 μM Cd treatment and 50% under 200 μM Cd treatment and led cells with MCN, while the MDA content and Evans blue absorption were not affected. The loss of membrane integrity occurred subsequently by 24 h. The increase in MDA content in root cells treated with 50, 100 and 200 μM Cd was significantly higher than the control. By 48 h, the MDA content increased 134, 178 or 208% in root cells treated with 50, 100 and 200 μM Cd, respectively. The Evans blue absorption was also affected by 24 h in roots when treated with 200 μM Cd and gradually increase by 48 h with the Cd concentration of the treatment. The decrease of mitotic activity triggered by 12 h was even higher by 24 h and the MI reduced to 44, 56 or 80% compared to the control in the three different Cd concentrations tested. The different kinetics of early in vivo physiological and cytogenetic responses to Cd might be relevant to the characterization of its toxicity mechanisms in disrupting primarily the mitosis process.
研究了水培培养的蚕豆幼苗根系中 Cd 暴露（50、100 和 200 μM）12 至 48 小时的应激反应动力学。重金属诱导的毒性症状和蚕豆根的生长抑制随着 Cd 浓度和处理时间的延长而逐渐增加。用 H2O2 生成来评估细胞内氧化应激。随着 Cd 的螯合和根生长抑制，H2O2 含量逐渐增加。通过丙二醛（MDA）含量和 Evans 蓝摄取评估脂质过氧化，通过有丝分裂指数（MI）和微核（MCN）值评估遗传毒性，同时在根尖中进行研究。在 50 或 100 μM Cd 处理下，根尖分生细胞的有丝分裂活性在 12 小时时损失了 15%，在 200 μM Cd 处理下损失了 50%，导致细胞出现 MCN，而 MDA 含量和 Evans 蓝吸收不受影响。随后在 24 小时时发生了膜完整性的丧失。用 50、100 和 200 μM Cd 处理的根细胞中 MDA 含量的增加明显高于对照。在 48 小时时，用 50、100 和 200 μM Cd 处理的根细胞中 MDA 含量分别增加了 134、178 或 208%。24 小时时，用 200 μM Cd 处理的根细胞中 Evans 蓝吸收也受到影响，并且随着处理 Cd 浓度的增加，48 小时时逐渐增加。在 24 小时时，12 小时触发的有丝分裂活性的降低甚至更高，MI 与对照相比分别降低到 44、56 或 80%。对 Cd 早期体内生理和细胞遗传学反应的不同动力学可能与描述其毒性机制有关，即主要破坏有丝分裂过程。
