Physiological Response And Enrichment Characteristics Of Gardenia Jasminoides And Gardenia Stenophylla To Cadmium,Lead And Zinc Contaminated Pollution Soil

In this study,two kinds of ornamental plant,Gardenia jasminoides and Gardenia stenophylla as the materials,a pot experiment were conducted to investigate the growth,physiological response,and heavy metals accumulation characteristics in plants under different concentration of Cd-Pb-Zn contaminated pollution in soil,aiming to explore the enrichment ability and mechanism of Gardenia jasminoides and Gardenia stenophylla for Cd,Pb,and Zn.The results showed that:(1)The growth of Gardenia jasminoides and Gardenia stenophylla were promoted in low level of Cd,Pb and Zn compound pollution(T1-T4),but opposite effects were observed when the Cd,Pb and Zn concentrations in high level(T5-T7).The root activity and chlorophyll content of Gardenia jasminoides and Gardenia stenophylla showed a trend of increasing gradually at first and then decline with the increase of Cd-Pb-Zn concentration,and the reduction of the latter was significantly greater than that of the former.The results showed that Gardenia jasminoides and Gardenia stenophylla had a strong tolerance to cadmium,lead and zinc pollution,and the tolerance of Gardenia jasminoides was stronger than that of Gardenia stenophylla.(2)The activities of SOD,POD,CAT and APX in two kinds of gardenias were higher in low concentrations of Cd,Pb and Zn contaminated pollution,the ability of scavenge reactive oxygen species in plants was strong,and avoid membrane oxidative damage.However,the activities of antioxidant enzymes in two kinds of gardenias were inhibited in the high concentration of Cd-Pb-Zn contaminated pollution,and MDA excessive accumulation,and the accumulation in Gardenia stenophylla was more than Gardenia jasminoides.Therefore,the plant suffered severe oxidation damage,and the oxidative damage of Gardenia stenophylla was larger than that of Gardenia jasminoides.(3)In roots,stems and leaves,Cd,Pb and Zn were predominated with the forms of HAc,NaCl and HCl.Moreover,Cd,Pb and Zn were mainly bound to cell wall and soluble fraction in roots,stems and leaves of Gardenia jasminoides and Gardenia stenophylla,a small amount of Cd,Pb and Zn were stored in cell membrane and organelles.Therefore,it was beneficial to enhance the tolerance and enrichment ability of Gardenia jasminoides and Gardenia stenophylla to cadmium,lead and zinc.(4)Under the Cd,Pb,and Zn contaminated pollution soil,the maximum accumulation of Cd,Pb and Zn in shoots of Gardenia jasminoides were 137.84 μg/plant,4546.76 μg/plant and 3123.93 μg/plant,83.82%~91.48% of the whole plants.The accumulation of Cd,Pb and Zn in shoots of Gardenia stenophylla were 90.64 μg/plant,2636.89 μg/plant and 2878.69 μg/plant,88.53% ~93.43% of the whole plants.The phytoremediation efficiency of Gardenia jasminoides was better than Gardenia stenophylla.In summary,Gardenia jasminoides and Gardenia stenophylla had large biomass and great ornament value,and strong tolerance and accumulation ability towards Cd,Pb,and Zn.Therefore,they were preferable phytoremediation germplasm resources in ornamental plant for Cd,Pb,and Zn contaminated polluted soil,and they are suitable for restore Cd,Pb,and Zn contaminated polluted soil when the concentration was low.