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重金属对大麦(Hordeum vulgare)毒性的研究   总被引:128,自引:1,他引:127       下载免费PDF全文
研究了6种重金属(Hg2+、Cd2+、Pb2+、Ni2+、Cu2+、Zn2+)对大麦幼苗生长及根尖细胞遗传学毒害作用.结果表明,随着重金属浓度的增加和处理时间的延长,大麦种子的萌发率、根生长速率和有丝分裂指数下降.1×10-2mol/L的Hg2+、Cd2+、Pb2+处理24h后完全抑制了细胞分裂,Hg2+、Cd2+和Pb2+诱发的染色体畸变率显著高于Ni2+、Cu2+和Zn2+.用5×10-3—5×10-4mol/L的Hg2+、Cd2+、Pb2+处理24h和Ni2+处理48h后,核仁结构发生分解,形成许多核仁颗粒并进入细胞质中,而Cu2+、Zn2+对核仁结构没有影响.6种重金属对大麦的细胞遗传学毒性顺序为Hg2+>Cd2+>Pb2+>Ni2+>Cu2+>Zn2+.文中还讨论了重金属对植物细胞的毒害机理.  相似文献
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The current study evaluates the cytogenetic effects of chromium (III) oxide nanoparticles on the root cells of Allium cepa. The root tip cells of A. cepa were treated with the aqueous dispersions of Cr2O3 nanoparticles (NPs) at five different concentrations (0.01, 0.1, 1, 10, and 100 μg/mL) for 4 hr. The colloidal stability of the nanoparticle suspensions during the exposure period were ascertained by particle size analyses. After 4 hr exposure to Cr2O3 NPs, a significant decrease in mitotic index (MI) from 35.56% (Control) to 35.26% (0.01 μg/mL), 34.64% (0.1 μg/mL), 32.73% (1 μg/mL), 29.6% (10 μg/mL) and 20.92% (100 μg/mL) was noted. The optical, fluorescence and confocal laser scanning microscopic analyses demonstrated specific chromosomal aberrations such as—chromosome stickiness, chromosome breaks, laggard chromosome, clumped chromosome, multipolar phases, nuclear notch, and nuclear bud at different exposure concentrations. The concentration-dependent internalization/bio-uptake of Cr2O3 NPs may have contributed to the enhanced production of anti oxidant enzyme, superoxide dismutase to counteract the oxidative stress, which in turn resulted in observed chromosomal aberrations and cytogenetic effects. These results suggest that A. cepa root tip assay can be successfully applied for evaluating environmental risk of Cr2O3 NPs over a wide range of concentrations.  相似文献
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