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Study On Physiological And Biochemical Responses To Cu And Zn Stress Of V.natans And H.verticillata

Posted on:2021-11-21Degree:MasterType:Thesis
Country:ChinaCandidate:Y WangFull Text:PDF
GTID:2491306473454944Subject:Hydraulic engineering
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To explore typical submerged plant V.natans and H.Verticillata in the physiological and biochemical response mechanism under heavy metal stress,different concentration of Cu2+and Zn2+stress cultivation V.natans and H.Verticillata 21d,which is divided into three stages,The effects of different concentrations Cu2+and Zn2+ were studied from three aspects:physiological and biochemical indexes,chlorophyll fluorescence parameters and transmission electron microscope technique.The results showed that:(1)The activities of SOD,POD and MDA in T1 treatment group(V.natans:Cu2+<0.2mg/L、Zn2+<2.0mg/L、Cu2++Zn2+<0.1mg/L+1.0mg/L;H.Verticillata:Cu2+<0.2mg/L、Zn2+<1.6mg/L、Cu2++Zn2+<0.1mg/L+0.8mg/L)were slightly lower than those in blank control group.SOD,POD and MDA increased significantly with the increase of heavy metal stress concentration within 7 days of stress culture.From the 7th day to the21st day of culture,its value showed a trend of first increasing and then decreasing.In terms of the activity of SOD,POD and MDA,the inhibition of heavy metals on the V.natans and H.Verticillata was as follows:>Cu2+stress>Zn2+stress.Within 7 days,the activity of the three antioxidant enzymes was significantly positively correlated with the concentration of heavy metals,but the correlation was not obvious in the subsequent cultivation.(2)Photosynthetic pigments:Ct,Ca,Cb,Cc,Ca/Cb and Cc/Ct indexes of V.natans and H.Verticillata significantly decreased with the increase of heavy metal concentration,but some indexes in T1 treatment group were higher than those in control group.The range of variation of compound stress was larger than that of single stress.Ct,Ca,Cb,Cc and Cc/Ct showed significant negative correlation,while Ca/Cb showed no significant correlation.(3)The V.natans and H.Verticillata Fv/Fm and Fv/Fo,Y(Ⅱ),q P these four fluorescence parameters T1 to T5 stage was significantly decline,T1 treatment group slightly higher than the control group.The three fluorescence parameters Y(NO),Y(NPQ)and q N showed NO significant changes within the range of T2 treatment(V.natans:Cu2+<0.4mg/L、Zn2+<4.0mg/L、Cu2++Zn2+<0.2mg/L+2.0mg/L;H.Verticillata:Cu2+<0.4mg/L、Zn2+<3.2mg/L、Cu2++Zn2+<0.2mg/L+1.6mg/L),but showed a significant decline with the increase of stress concentration.The composite stress indexes of the stress21d,T4 and T5 groups showed an upward trend and then a downward trend.On the whole,the variation range of each index under compound stress was larger than that under singlestress.Within 7 d,Fv/Fm,Fv/Fo,Y(Ⅱ),q P the fluorescence parameters have no obvious correlation between four;Y(NO),Y(NPQ)and q N were significantly positively correlated with Cu and Zn.14 d-21 d,Fv/Fm,Fv/Fo,Y(Ⅱ),q P has significant negative correlation.(4)According to the light response curve,the light curve of P.laminaria and P.laminaria showed a sharp rise and then a gentle decline with the increase of PAR,and the maximum ETR was found at the PAR of 200 mol·m-2·s-1.On the 21thday of the stress culture,the indexes of compound stress and the light response curve in the T5 treatment group could not be measured,but black algae could.(5)The chloroplasts and cell walls of the two submerged plants changed more under the influence of heavy metals,and chloroplasts were more sensitive to heavy metals than cell walls.The tolerability of Cu2+and Zn2+to single stress and compound stress was higher than that of H.Verticillata.The toxic effect of Cu2+and Zn2+ on ultrastructure was synergistic.
Keywords/Search Tags:submerged plants, Cu and Zn, Physiological indexes, chlorophyll fluorescence, ultrastructure
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