The Enrichment And Response Of Energy Crop Sweet Sorghum And Maize To Heavy Metal Stress

The 13th Five-Year Plan emphasized food security.But heavy metals contamination is still serious in China,which is of great significance to repair heavy metal contaminated soil.Based on the concept of phytoremediation technology,the response and enrichment of sweet sorghum and maize to single heavy metal cadmium and chromium stress were studied by pot experiment.The aim of this study was to compare the enrichment and resistance of different energy crops to heavy metals stress,providing theoretical basis for energy crops as phytoremediation materials.In this study,different treatments were prepared including CK,Cdl,Cd2,Cd3,Cd4,Pb1,Pb2,Pb3,Pb4,Cr1,Cr2,and Cr3.The results are as follows:The Cd contents of heavy metals in different organs of sweet sorghum were higher than those of maize under Cd treatments.The highest Cd content of sweet sorghum root and stem was 2.88 mg/kg and 0.53mg/kg,respectively,which was significantly higher than that of maize.The Pb content of maize leaves was 8.52mg/kg and 13.46mg/kg under Pb3 and Pb4 treatments,respectively,which was significantly higher than that of sweet sorghum leaves.Cr content of sweet sorghum and maize was different under Cr treatments.In general,the Cr content of sweet sorghum and maize increased with the increase of heavy metal Cr concentration.The sweet sorghum aboveground part accumulation of Cd was 6.28-59.71μg,which was higher than that of maize under different Cd stress.Under Pb stress,the accumulation of Pb in sweet sorghum and maize was similar.But at high concentrations(Pb3 and Pb4 treatments),the Pb accumulation in maize crown was 476.07μg,652.44μg,respectively,higher than that in sweet Sorghun.Under Cr3 treatment,the Cr accumulation in maize was significantly lower than that in sorghum.The results of correlation analysis of different indexes and heavy metal accumulation on the aboveground parts,at sweet sorghum and maize growth seedling stage,are as follows.Under the Cd stress,the correlation coefficient between the different indexes of sweet sorghum and the Cd accumulation on the aboveground part was lower.But under the Pb stress,the relative conductivity and POD activity of the leaves were positively correlated with the Pb accumulation in the aboveground part,with the correlation coefficients 0.743 and 0.701.At jointing stage,the leaf chlorophyll content was negatively correlated with the Cd enrichment in the aboveground part under Cd stress,while the relative conductivity,MDA content and POD activity of the leaves were related to the aboveground part Pb content under Pb stress.