| In recent years,with the increasingly serious pollution of heavy metals,the safe production of bulk food crops has attracted more and more attention,and the variety screening of low accumulation crops has also become a research hotspot in recent years.The research shows that the screening of crop varieties with low accumulation of heavy metals has the advantages of simple operation,low risk and easy popularization.As one of the widely planted crops in China,corn has the characteristics of large biomass and short growth cycle,and the enrichment ability of grains to heavy metals is low,while the enrichment ability of roots and stems and leaves to heavy metals is strong,and the stems and leaves can also be used as biomass carbon for soil remediation after recovery,Therefore,it has great application potential in reducing the content of heavy metals in crops and Cd contaminated soil remediation.In order to screen out maize varieties with low Cd accumulation in grains and high Cd accumulation in stems and leaves,and to study the differences of Cd accumulation and transport among different maize varieties,50 maize varieties were used as materials to carry out field experiments in severely Cd polluted farmland for two consecutive years.The results are as follows:（1）Under the condition of heavy Cd pollution in farmland,the economic shape,biomass and yield of different maize varieties showed significant interspecific differences.The yield range of 50 Maize Varieties in 2020 is 34.82～179.76 g·plant-1,the yield range of Maize Varieties with low accumulation of grain Cd in 2001 is 121.92～216.40 g·plant-1,and the yield range of Maize Varieties with high accumulation of stem and leaf Cd in 2001 is 114.66～182.44 g·plant-1.（2）There were significant differences in Cd content in grains,stems and leaves of 50maize varieties.The content of Cd in grains met the national feed hygiene standard.29 maize varieties such as Xindan 58 and Meijia 303 were divided into dominant varieties with low accumulation of Cd in grains by cluster analysis;31 maize varieties such as Xindan 58 and Dika 653 were divided into dominant varieties with high Cd concentration in stems and leaves;19 varieties such as hongdaji gengyu 505 and qiule 618 were divided into dominant varieties with medium and low Cd enrichment in stems and leaves.（3）There were significant differences in the distribution of Cd in different parts of plants of different maize varieties.The maize varieties with medium and low accumulation of Cd in grains showed root>stem and leaf>core>grain;Maize varieties with high Cd concentration in stem,leaf and grain showed stem and leaf>root>core>grain.（4）The roots of Maize Varieties with medium and low accumulation of Cd in grains have a strong ability to enrich Cd in soil,while the stems and leaves of Maize Varieties with high accumulation of Cd in grains have a strong ability to enrich Cd in soil.Specifically,the enrichment coefficient of Maize Varieties with medium and low accumulation of Cd in grains:root>stem and leaf>core>grain;The enrichment coefficient of Maize Varieties with high Cd enrichment in stem,leaf and grain:stem and leaf>root>core>grain.The concentration of Cd in different parts of maize plant was as follows:stem and leaf>root and core>grain.（5）The Cd transport coefficients of different parts of different maize varieties were as follows:stem and leaf>core>grain;The high,medium and low accumulation of Cd in grains means that the Cd transport capacity of stems,leaves and grains of maize varieties decreases in turn,and the Cd transport capacity of grains is weak.（6）There was no significant correlation between yield and plant height and grain Cd content of different maize varieties;It was positively correlated with the maximum leaf length,leaf width,leaf area,Cd content in roots,stems,leaves and cores.（7）The absorption of nutrients and Cd in rhizosphere soil by different maize varieties was significantly different,and Cd in maize plant was positively correlated with Cd content in soil. |
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