不同浓度钙·锌抑制剂对烟草镉积累及亚细胞分布的影响

目的]探讨钙锌互作对镉元素在烟草体内亚细胞分布的影响。方法]以烟草南江三号为研究材料,通过添加不同浓度钙、锌2种抑制剂,采用土培盆栽试验,研究烟草镉的亚细胞分布。结果]烟草叶部和根部的整个亚细胞中,镉含量分布大小顺序为胞液、细胞壁、叶绿体、线粒体。土壤中镉浓度为1 mg/kg时,加入钙抑制剂100 mg/kg,烟草根部叶绿体、细胞器和胞液的镉含量均下降,而细胞壁中的镉含量增加;加入锌抑制剂50 mg/kg,烟草所有亚细胞中的镉含量均有所下降,说明加入锌抑制剂50 mg/kg比加入钙抑制剂100mg/kg的效果好。土壤镉浓度为5 mg/kg时,烟草根部和叶部细胞器的镉含量都有所上升,其余3个亚细胞中的镉含量减少。结论]烟草中镉在胞液中的分布多于细胞壁,叶绿体和线粒体镉含量少,在不同浓度钙、锌处理下烟草对镉的耐性加强,镉在烟草体内结合在细胞壁上,通过主动运输进入胞液,胞液区室化作用明显,可能是烟草耐镉的主要机制,减少烟叶镉含量的重要途径。

Effects of Different Concentrations of Calcium and Zinc Inhibitors on Accumulation and Subcellular Distribution of Cadmium in Tobacco

Objective] The aim was to explore effects of different concentrations of calcium and zinc inhibitors on cadmium accumulation and subcellular distribution in tobacco.Method] Taking Nanjiang 3 as material,we studied the subcellular distribution of cadmium in tobacco by soil culture pot experiment with adding different concentrations of calcium and zinc inhibitors.Result] The cadmium content in whole subcellular of leaves and roots of tobacco was in order of cytosol,cell wall,chloroplast and mitochondria.When the concentration of cadmium in soil was 1 mg/kg,and the concentration of calcium inhibitor was 100 mg/kg,the cadmium decreased in cytosol,chloroplast and organelles of tobacco root,but increased in cell wall;when the concentration of cadmium in soil was 1 mg/kg,and the concentration of zinc inhibitor was 50 mg/kg,the cadmium decreased in all subcellular of tobacco,which indicated that adding 50 mg/kg zinc inhibitor had better effect than adding 100 mg/kg calcium inhibitor.When the concentration of cadmium in soil was 5 mg/kg,the concentration of cadmium in organelles of tobacco leaves and roots all increased,while the concentration of cadmium in the other 3 subcellular decreased.Conclusion] The cadmium in cytosol is more than that in cell wall,and the cadmium in chloroplast and mitochondria was little.The tolerance of tobacco under different concentrations of calcium and zinc is strengthened.The cadmium in tobacco is combined on cell wall,and then transported into cytosol,and the cytosol has strong chamber,which may be main mechanism and important way to reduce cadmium in tobacco.