铅镉复合胁迫下莲藕对铅镉的富集及其生理变化

 通过盆栽试验，研究了100 mg · kg^-1 Pb轻度污染 + 0.2 mg · kg^-1 Cd轻度污染、500 mg · kg^-1 Pb重度污染 + 0.2 mg · kg^-1 Cd轻度污染、100 mg · kg^-1 Pb轻度污染 + 1.0 mg · kg^-1Cd重度污染、500 mg · kg^-1 Pb重度污染 + 1.0 mg · kg^-1 Cd重度污染、0 + 0（对照）等5个浓度梯度Pb、Cd复合胁迫下莲藕各器官中Pb和Cd的富集特性，以及莲藕生理生化、品质以及产量的变化。结果表明，Pb + Cd复合胁迫下，莲藕各器官中Pb、Cd富集与外施Pb、Cd浓度呈正相关，且在100 mg · kg^-1 Pb + 0.2 mg · kg^-1 Cd轻度污染水平下各器官中Pb和Cd含量就已超过国家食品卫生标准。总体来说，荷叶和膨大茎富集最多，叶柄和匍匐茎次之。Pb、Cd在莲藕中富集产生了一定的毒性反应，表现为：总叶绿素含量呈下降趋势；荷叶和莲藕膨大茎中MDA含量均有所增加，且荷叶中变化幅度更大；荷叶中可溶性糖含量下降、可溶性蛋白先升后降。莲藕膨大茎中可溶性糖、可溶性蛋白等变化不大，但维生素C含量在Pb + Cd轻度污染显著升高，后又逐渐下降，且在Pb + Cd重度污染水平与对照差异极显著。外施Pb、Cd使莲藕产量逐渐下降，在Pb + Cd重度污染水平下，显著低于对照。

Effects of Heavy Metals Pb and Cd on the Physiological Response: and Accumulation in Lotus Root

Effects of five combinations of two heavy metals，Pb and Cd，as pollutersat at both lower （100 mg · kg^-1 Pb + 0.2 mg · kg^-1 Cd），both higher（500 mg · kg^-1 Pb + 1.0 mg · kg^-1 Cd），Pb lower（100 mg · kg^-1）and Cd higher（1.0 mg · kg^-1），Pb higher（500 mg · kg^-1）and Cd lower（0.2 mg · kg^-1），and non-treated（the control）in big pots on their accumulation characteristics，physiological and biochemical indicators，produce qualities and yields in lotus root（Nelumbo nucifera Gaertn.）were analyzed. The result showed that there were a positive correlation between Pb and Cd accumulations in the various organs of louts root and the levels of Pb and Cd supplemented to the soil. And it occurred even in the lower concentrations，Pb and/or Cd still exceeded the national food hygienic standards. As a whole，the accumulation patterns showed the heavy metals are more in lotus leaf，swollen stem，petiole and creeping stem. The toxicity of Pb or Cd accumulated in lotus root displayed that total chlorophyll content decreased and the MDA content increased in lotus leaf than swollen stem，the soluble sugar declined and the soluble protein first increased and then decreased in the lotus leaf，however，there was no obvious change in swollen stem；The vitamin C increased at lower levels of both Pb and Cd，then declined，and a significant difference in higher level soil of Pb and Cd than the control. Also，we can see that the yield of swollen stem of lotus dropped down along with the concentration increases and had a significant difference in Pb + Cd higher soil than the control.