重金属对大麦(Hordeum vulgare)毒性的研究

TOXICITY OF HEAVY METALS TO HORDEUM VULGARE

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．

The toxic effects of six heavy metals (Hg 2+ , Cd 2+ , Pb 2+ , Ni 2+ , Cu 2+ , Zn 2+ ) at different concentrations on H ordeum vulgare seedlings were studied. The results indicated that the percentage of seed germination rate of root growth and mitotic index decreased progressively with the increasing of concentrations of heavy metals and treatment durations. After 24 h treatment with 1×10 -2 mol/L Hg 2+ , Cd 2+ , and Pb 2+ , cell division was completely inhibited by Hg 2+ , Cd 2+ , Pb 2+ . The total frequency of chromosomal aberrations induced by Hg 2+ , Cd 2+ , Pb 2+ was higher than that of Ni 2+ , Cu 2+ and Zn 2+ . After the treatment with Hg 2+ , Cd +2 , Pb 2+ at concentrations of 5×10 -3 —5×10 -4 mol/L for 24 h and Ni 2+ at same concentration for 48 h, the nucleolus was disintegrated and forming a large amount of nucleolar particles which go into the cytoplasm from the cell nucleus. But after the treatment with Cu 2+ and Zn 2+ , the nucleous was not affected. The order of six heavy metals on cytogenetical toxical effects is Hg 2+ >Cd 2+ >Pb 2+ >Ni 2+ >Cu 2+ >Zn 2+ . The possible mechanism of poisoning of heavy metals on plant cells was also discussed.