The Study On Uptake And Accumulation Of Calendula Officinalis To Cd Contaminated Soil

The rapid development of industry and agriculture has brought serious harm to the environment of human existence.The soil was polluted by heavy metal seriously.In particular,Cd pollution has seriously threatened human health.Therefore,it is urgent to solve the problem of heavy metal pollution.Phytoremediation is a heavy metal contaminated soil remediation technology that integrates economy and environmental protection.Studies have shown that Calendula officinalis has the effect of remediation of heavy metals contaminated soil,but Cd will not affect the germination of calendula officinalis seed?How does Cd contamination affect Calendula officinalis patience and enrichment ability?How does the use of chemical fortifiers affect the recovery of Cd contaminated soil by Calendula officinalis?The answer to these questions is not clear.So in this article,we study the Cd tolerance of Calendula officinalis,as well as its ability of Cd transfer and enrichment by analyzing seed germination parameters and physiological index in pot experiment under Cd stress with different Cd concentration as well as chemical enhancer effect on Calendula officinalis.The main results are as follows:?1?There was little effect of different Cd concentrations on the germination rate and germination potential of Calendula officinalis seeds.However,the germination index firstly increased and decreased with the increase of Cd concentration,then reached the maximum,51.86,at Cd concentration of 30 mg?kg^-1.With the increase of Cd concentration,root area,root number and root length of Calendula officinalis has the same varying tendency as germination index,while root diameter continued to increase.?2?The plant height and biomass of Calendula officinalis firstly increased and decreased with the increase of Cd concentration,then reached the maximum at Cd concentration of 30mg?kg^-1.However,the content and accumulation of Cd in shoot and root of Calendula officinalis increased significantly with the increase of Cd concentration?P<0.05?.The transfer efficiencies of Calendula officinalis were less than 1,and the shoot enrichment efficiencies were greater than 1under all treatments.Also,the shoot enrichment efficiencies increased with the increased Cd concentration,and reached the maximum,459.02?g,under 100 mg?kg^-11 Cd treatment.?3?When the soil Cd pollution was not serious(30 mg?kg^-1),either SDS or EGTA treatments could enhance the tolerance,enrichment efficiencies and accumulation of Calendula officinalis to Cd,and both had synergistic effects.Under the treatment of chemical enhancer combination?0.5mmol?kg^-11 SDS-1.0 mmol?kg^-11 EGTA?,the Calendula officinalis biomass,tolerance,enrichment efficiencies and accumulation of Cd were the highest.When the concentration of Cd in contaminated soil was higher(100 mg?kg^-1),either SDS or EGTA treatments can enhanced Cd tolerance,enrichment efficiencies and accumulation of Calendula officinalis.These indexes reached their maximum under the treatment of chemical enhancers combination(1.0 mmol?kg^-1SDS-EGTA).In conclusion,Calendula officinalis has strong tolerance to heavy metal Cd.Cd with different concentrations had no significant effect on the seed germination,and the root growth was promoted when the Cd concentration was lower.At the same time,low concentrations of Cd can promote the growth of Calendula officinalis,as well as Cd tolerance and enrichment efficiencies.Both single and combination treatment of SDS and EGTA could enhance the ability of Calendula officinalis to repair Cd-contaminated soils.The soil with lower degree of pollution can be repaired under the treatment of 0.5 mmol?kg^-11 SDS with 1.0 mmol?kg^-11 EGTA and the combination of 1.0mmol?kg^-11 SDS with 1.0 mmol?kg^-11 EGTA can be used for the best reparative effect for high-degree-pollution soil.