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    乔永, 周金星, 王小平. Pb、Cd复合胁迫对桑树种子萌发及幼苗生长的影响[J]. 北京林业大学学报, 2020, 42(4): 32-40. DOI: 10.12171/j.1000-1522.20190244
    引用本文: 乔永, 周金星, 王小平. Pb、Cd复合胁迫对桑树种子萌发及幼苗生长的影响[J]. 北京林业大学学报, 2020, 42(4): 32-40. DOI: 10.12171/j.1000-1522.20190244
    Qiao Yong, Zhou Jinxing, Wang Xiaoping. Effects of lead and cadmium combined stress on seed germination and seedling growth of mulberry[J]. Journal of Beijing Forestry University, 2020, 42(4): 32-40. DOI: 10.12171/j.1000-1522.20190244
    Citation: Qiao Yong, Zhou Jinxing, Wang Xiaoping. Effects of lead and cadmium combined stress on seed germination and seedling growth of mulberry[J]. Journal of Beijing Forestry University, 2020, 42(4): 32-40. DOI: 10.12171/j.1000-1522.20190244

    Pb、Cd复合胁迫对桑树种子萌发及幼苗生长的影响

    Effects of lead and cadmium combined stress on seed germination and seedling growth of mulberry

    • 摘要:
      目的研究不同含量Pb、Cd单一及复合胁迫对桑树种子萌发、幼苗生长的影响,以及桑树对重金属Pb、Cd的富集和迁移,探索桑树对修复Pb、Cd污染土壤的潜能。
      方法以桑树种子和幼苗为实验材料,通过发芽实验和盆栽实验研究不同含量Pb(0、250、500、750、1 000、1 250 mg/kg)和Cd(0、0.2、1、25、75、100 mg/kg)单一及复合胁迫对桑树种子发芽率、幼苗株高、生物量等影响,以及Pb、Cd在桑树根、茎、叶中的富集和迁移。
      结果(1)不同含量Pb、Cd单一及复合胁迫均对桑树种子萌发产生抑制作用;(2)低含量Pb、Cd(250、0.2 mg/kg)对桑树幼苗株高、生物量产生促进作用,当含量升高时转为抑制作用。(3)Pb、Cd主要积累于桑树根系中,低含量的Pb(250 mg/kg)会促进桑树对Cd的富集和迁移;桑树对Cd的富集及迁移系数高于Pb,但富集系数和迁移系数最高值均 < 1。Pb、Cd复合胁迫下,桑树对Pb、Cd富集和迁移系数小于单一胁迫;当Pb、Cd含量升高时,Pb、Cd富集系数和迁移系数均呈现下降趋势。
      结论不同含量Pb、Cd均会不用程度的抑制桑树种子萌发,抑制作用随Pb、Cd含量升高而增强。桑树不属于超富集植物,但对低含量Pb、Cd富集及转移系数较高,并且低含量Pb、Cd会促进桑树生长,可在低含量Pb、Cd污染土壤中开展种桑养蚕模式进行土壤重金属污染修复。

       

      Abstract:
      ObjectiveThis paper aims to study the effects of single and combined stress of lead and cadmium at different concentrations on seed germination and seedling growth of mulberry, as well as the bio-enrichment and transfer of Pb and Cd in mulberry to explore the repair capacity of mulberry on contaminated soil.
      MethodThe germination and pot-based experiment was designed with different concentrations Pb (0, 250, 500, 750, 1 000, 1 250 mg/kg) and Cd (0, 0.2, 1, 25, 75, 100 mg/kg) to study the germination rate of seed, plant height and biomass of mulberry, as well as the enrichment and transfer coefficients of Pb and Cd in mulberry roots, stems and leaves.
      Result(1) The germination of mulberry seeds was inhibited by single and combined stress at different concentrations of Pb and Cd. (2) Low concentrations of Pb and Cd (250, 0.2 mg/kg) promoted the high biomass of mulberry seedlings, which turned into inhibition when the concentration increased. (3) Pb and Cd were mainly accumulated in mulberry roots, and low concentration of Pb (250 mg/kg) would promote Cd enrichment and transfer in mulberry. The enrichment coefficient and transfer coefficient of Cd were higher than Pb, but the maximum values of both were less than 1. The bio-enrichment coefficient and transfer coefficient of combined stress were lower than those of single stress. The enrichment coefficient and transfer coefficient of Pb and Cd will be reduced when the concentration of Pb and Cd increased.
      ConclusionThe germination of mulberry seeds is inhibited by different concentrations of Pb and Cd, and the inhibitory effect increases with the increase of Pb and Cd concentration. Although mulberry is not a hyper-accumulator, the enrichment coefficient and transfer coefficient of low-concentration Pb and Cd are relatively high, and low-concentration Pb and Cd would promote the growth of mulberry, which can be used to plant mulberry and raise silkworm in soil contaminated with low-concentration Pb and Cd for soil heavy metal pollution remediation.

       

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