Ecophysiological Response Of Oenothera Villosa In Cadmium, Lead And Copper Stress

The effects of Cd,Pb,Cu stress on seed germination,physiological indicators,photosynthetic characteristics and chlorophyll fluorescence parameters of O.villosa were studied at different Cd,Pb,Cu concentrations using culture dish and pot experiment.The response mechanism,absorption and transport capacity of O.villosa for heavy metals stress were explored,in order to provide scientific basis for phytoremediation of heavy metal contaminated soil,and new ideas for ecological invasion plants resource utilization.The main results are as follows:1.An initial germination and the germination peak of O.villosa were delayed by heavy metal stress(Cd²⁺≥100mg/L,Pb²⁺≥1000mg/L,Cu²⁺≥200mg/L).When Cd²⁺concentration was 10-150mg/L,Pb²⁺concentration was 250mg/L,Cu²⁺concentration was 25mg/L,the length of primary root and radicel,as well as biomass of O.villosa were significant inhibited,while the seed germination rate,germination energy,germination index and vigor index of O.villosa were not show any obvious effects.2.when Cd²⁺concentration was 25,50mg/kg,Pb²⁺concentration was 500,1000mg/kg,the content of MDA,Pro and soluble protein,activity of SOD,POD and CAT of O.villosa were increased compared with the controls.When Cd²⁺concentration≥100mg/kg,Pb²⁺concentration was 1500mg/kg,the content of soluble protein,activity of SOD,POD and CAT were decreased compared with the controls.When Cu²⁺concentration was 1500mg/kg,the content of MDA was significantly increased,whereas the content of soluble protein,activity of SOD,POD and CAT were significantly decreased,and other groups differences were not significant.3.When Cd²⁺concentration was 100mg/kg,Pb²⁺concentration was 1500mg/kg,Cu²⁺concentration was 1500mg/kg,the Pn,Gs and Ci of O.villosa were decreased compared with the controls,the inhibition of photosynthesis was mainly caused by stomatal factor.When Cd²⁺concentration was 50mg/kg,Pb²⁺concentration was1000mg/kg,Cu²⁺concentration was 1000mg/kg,the Pn was decreased,but the Ci was increased,the inhibition of photosynthesis was mainly caused by non-stomatal factor.Tr of O.villosa was lower than that of the control group with the Cd and Cu stress.WUE basically showed the trend after first ascending,while Ls was the opposite.Tr and WUE were increased first and decreased afterwards with the Pb stress.4.The content of chlorophyll had significant correlation with some photosynthetic characteristics of O.villosa.When Cd²⁺concentration was 100mg/kg,the contents of Chla and Chlb,the value of Chla/b of O.villosa were significantly reduced.When Pb²⁺and Cu²⁺concentration were 1500mg/kg,the content of Chla and the value of Chla/b were significantly reduced.It showed that the chloroplast membrane structure damaged.The chlorophyll content of O.villosa in other groups were not show any significant effects.5.Fo of O.villosa was significantly increased compared with the controls by heavy metal stress(Cd²⁺≥100mg/kg,Pb²⁺≥1000mg/kg),while Fm and Fv/Fo were significantly decreased compared with the controls.It showed that the PSII reaction center damaged.Yield,ETR and qP of O.villosa were significantly decreased,whereas qN was significantly increased within Cd²⁺≥5mg/kg and Pb²⁺≥500mg/kg.When Cu²⁺concentration was 1500mg/kg,Fo and qN were significantly increased,however Fm,Fv/Fm,Fv/Fo,Yield,ETR,qP were significantly decreased.It showed that the photosynthetic capacity decreased.That of the other groups differences were not significant.6.The maximums of accumulations of Cd,Pb,Cu were 96.79 mg/kg,277.86mg/kg and 1256.69mg/kg respectively,and the maximums of enrichment coefficient were 1.35,0.19 and 1.00 respectively.and the amount of heavy metal in the underground organ and the enrichment coefficient were higher than that of the above ground organs.The transfer coefficient of O.villosa to Cd,Pb,Cu were in the range of0.11-0.29,0.07-0.46,0.1-0.23 respectively.The O.villosa belongs to Cd,Cu root accumulation type plant,Pb’s avoid type plant.The O.villosa has certain tolerance and adsorption capacity of heavy metal（Cd,Pb and Cu）.In the control and repair of heavy metal contaminated soil with potential application value.At the same time,it would provides new ideas for the utilization of invasive plant ecological resources.