Phytoextraction In Cd Or Cd-Pb Contaminated Soils By Suaeda Salsa

Many saline soils were affected by heavy metals.Cd and Pb had strong biotoxicity and usually as compound pollution existed in the soil.The remediation of such contaminated soil was widely concerned.In this study,several halophytes were used as experimental materials,the sand culture pot experiment was conducted in the greenhouse.Indicators,such as Enrichment coefficient,Transfer coefficient,Root net absorption capacity,Root net translocation capacity,Extraction rate,and Extraction duration,were investigated.The aim of this study was to screen out plants with the potential for remediation of Cd and Pb contaminated saline soils.Some studies have reported that Cd and Pb stress could lead to the inorganic ions metabolism disordered,thus affecting the plant remediation effect.Therefore,this study further selected the Suaeda salsa as experimental material,set different concentrations of Cd,Pb and salinity levels.The contents of Na,K,Ca,Mg,Mn,Zn and Fe contents has analyzed.The aim of this experiment was to investigate the effect of Cd and Pb on inorganic ions accumulation mechanism in Suaeda salsa.This study provide scientific basis for fertilizer management and inorganic ions regulation in remediation practice of Suaeda salsa.This study indicated that:?1?Cd and Pb uptake and translocation ability of Suaeda salsa were significantly higher than those of the other three halophytes.A certain concentration of salt could promote plant growth and absorption of Cd and Pb in four halophytes.For Suaeda salsa,the biomass was 13.17 g?pot^-1,and Cd content in shoot was 97.04 mg?kg^-1.Cd extraction rate was 31.80%,Cd extraction amount was 938.20?g·pot^-1,and the extraction duration was 3.14 years.Suaeda salsa has great potential in remediation of heavy metal contaminated saline soils.?2?Under the different concentrations of Cd and salinity levels,the biomass of Suaeda salsa was 11.25 g?pot^-1,Cd content in shoot was 132.12 mg?kg^-1,Cd extraction rate was 70.12%,the extraction duration was 1.91 years,Cd enrichment coefficient was 64.32,and Cd transfer coefficient was 1.10.Compared to Cd and Pb compound pollution,Suaeda salsa performed better abilities of Cd enrichment and transfer abilities,Suaeda salsa has great potential in remediation of Cd contaminated saline soils.?3?With the increase of NaCl concentration,the content of Na⁺increased significantly,while the K⁺content decreased significantly.In this study,with the increase of NaCl concentration,the Ca²⁺content of stem and leaf of Suaeda salsa was decreased,which indicated that NaCl had an inhibitory effect on the transport of Ca²⁺to the shoot.?4?With the increase of NaCl concentration,the content of Mg⁺was decreased,which indicated that the salt had an inhibitory effect on the absorption of Mg²⁺in Suaeda salsa.The concentration of Mg⁺in the stem and leaf of Suaeda salsa was significantly higher than that of the root,which indicated that the Suaeda salsa had good transport ability to Mg²⁺.?5?Under the condition of Cd treatment,the lower concentration of Cd promoted Zn²⁺and Fe³⁺enrichment,while the higher concentration of Cd inhibited Zn²⁺and accumulation of Fe³⁺.The low concentration of Cd treatment promoted the enrichment of Mn ions in the stem and leaf of Suaeda salsa.Under NaCl treatment,the content of Zn²⁺in stem and leaf of Suaeda salsa was significantly higher than that in roots,indicating that NaCl treatment promoted the transport of Zn²⁺in Suaeda salsa.The content of Fe³⁺in the roots of Suaeda salsa was much larger than that in the stem and leaf,which indicates that the transport capacity of Fe³⁺was limited.In summary,Suaeda salsa had great Cd remadiation potential in Cd and Pb compound pollution or Cd contaminated saline soils.It was suggested that the concentration of inorganic ions such as Na,K,Mg,and Zn should be controlled to alleviate the Cd stress,and then improve the remediation efficiency of Suaeda salsa.