锰肥和锌肥种子包衣对花生的降镉效果

Effects of manganese fertilizer and zinc fertilizer seed coating on cadmium reduction in peanut

花生对土壤中的镉(Cd)具有较强的富集能力,我国花生Cd超标现象局部地区较为严重,Mn、Zn离子可通过拮抗作用降低作物对Cd的吸收,本研究探究Mn肥、Zn肥种子包衣处理对花生Cd吸收转运的影响,以期为花生产地土壤Cd污染风险管控与修复提供技术支撑。首先通过种子萌发试验筛选出3个锰(Mn)和锌(Zn)较适宜的包衣剂浓度,再进一步通过盆栽试验筛选出降镉效果最优的Mn和Zn包衣剂浓度,并探究了Mn肥和Zn肥种子包衣对Cd污染土壤上花生富集转运Cd的影响。种子萌发试验结果表明,中低浓度的Mn肥、Zn肥种子包衣处理不会影响种子发芽率且可以促进根生长,浓度过高则会明显抑制种子萌发。盆栽试验结果表明,Mn肥和Zn肥种子包衣剂中,3%锰肥包衣剂(Mn3)和2%锌肥包衣剂(Zn2)包衣处理籽粒降镉效果最显著,降镉率分别达到19.0%和24.1%,其中Zn2降镉效果更优。与对照相比,Mn3和Zn2处理根系Cd富集系数均显著降低,根向茎叶Cd转运能力明显增加,茎叶向籽粒Cd转运系数呈下降趋势,根系向籽粒Cd转运系数则无明显变化。Mn3和Zn2处理花生植株总Cd吸收量相比对照分别下降了9.18%和13.6%,花生籽粒及根系Cd含量均与根系中Mn、Zn元素含量呈显著负相关关系。综上,利用Mn、Zn种子包衣处理可通过抑制根系对Cd的吸收以及影响Cd在花生体内的转运来降低花生籽粒Cd含量。本研究提出了利用种子包衣来降低花生Cd含量的技术,为花生产地镉污染风险管控提供了新方法。

Peanut has a fairly strong ability of accumulating cadmium(Cd)from the soil,and the problem of Cd content in peanut exceeding the food safety standard is serious in some regions of China.Seed coating is a common technology to control diseases and insect pests and enhance stress resistance in peanut production,but the research of using seed coating technology to control Cd pollution risk in peanut producing areas has not been reported.This study first screened out three suitable concentrations of manganese(Mn)and zinc(Zn)coating agents by seed germination test,and then further screened out the concentration of coating agent with the best Cd reduction effect by pot experiment.The effect of Mn fertilizer and Zn fertilizer seed coating on Cd transfer within peanut plant in Cd-contaminated soil was further explored through pot experiment.The results of seed germination test showed that the seed coating treatment with low to moderate concentrations of Mn and Zn fertilizer did not affect the seed germination rate and could promote the root length,while the excessive concentration could obviously inhibit the seed germination.The results of pot experiment showed that among the seed coating agents of Mn and Zn,3%Mn fertilizer coating agent(Mn3)and 2%Zn fertilizer coating agent(Zn2)had the most significant effect on reducing Cd in peanut seeds,with the Cd reduction rates reaching 19.0%and 24.1%respectively,and Zn2 had the better Cd reduction effect.Compared with the control,the Cd bioaccumulation factor of roots in the two treatments decreased significantly,the Cd translocation factor(TF)from roots to shoots increased significantly,the TF from shoots to seeds decreased,while the TF from roots to seeds had no obvious change.Compared with the control,the absorption of Cd in peanut plants under Mn3 and Zn2 treatments decreased by 9.18%and 13.6%.There was a significant negative correlation between the contents of Cd in peanut seeds and roots and the contents of Mn and Zn in roots.Seed coating with Mn and Zn can reduce the Cd content in peanut seeds by inhibiting the absorption of Cd by roots and the transport of Cd within peanut plant.This study put forward the technology of reducing Cd content in peanut by seed coating,which provided a new method for risk control of Cd pollution in peanut producing areas.